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000
FXUS63 KUNR 011101
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
401 AM MST SUN FEB 1 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 324 AM MST SUN FEB 1 2015

UPPER LEVEL ANALYSIS HAS LARGE TROF ACROSS THE NORTH CENTRAL CONUS
WITH RIDGE ALONG THE WEST COAST. UPPER SHORTWAVE BRINGING SNOW TO
THE AREA AT THE MOMENT IS QUICKLY SHIFTING EAST WITH SKIES
CLEARING ACROSS EASTERN MONTANA. AT THE SURFACE...ARCTIC HIGH IS
SETTLING INTO THE NORTHERN PLAINS WITH WINDS MAINLY OUT OF THE
NORTH AT 5 TO 15 MPH. TEMPERATURES ARE MAINLY IN THE SINGLE
DIGITS.

TODAY...UPPER SHORTWAVE CONTINUES TO SHIFT QUICKLY EAST AS ARCTIC
HIGH PRESSURE SLIDES SOUTH THROUGH THE EASTERN DAKOTAS. LIGHT SNOW
WILL QUICKLY TAPER OFF EARLY THIS MORNING WITH SKIES BECOMING
PARTLY CLOUDY WEST TO EAST. TEMPERATURES WILL BE CHILLY...IN THE
TEENS ACROSS THE SD PLAINS...TO THE MID 20S IN NE WYOMING.
NORTHERLY WINDS WILL DIMINISH BY THE AFTERNOON.

TONIGHT...UPPER FLOW REMAINS NORTHWEST WITH BROAD RIDGE ACROSS THE
WESTERN CONUS. VARIABLY CLOUDY SKIES EXPECTED WITH TEMPERATURES
DROPPING OFF QUICKLY IN THE EVENING. LOWS WILL MAINLY BE IN THE
SINGLE DIGITS...WITH SOME BELOW ZERO TEMPS POSSIBLE ACROSS SOUTH
CENTRAL SOUTH DAKOTA.

MONDAY...NEXT UPPER SHORTWAVE IN NORTHWEST FLOW WILL GRAZE
NORTHERN PORTIONS OF THE FORECAST AREA...BRINGING SOME LIGHT RAIN
OR SNOW SHOWERS TO NORTHWEST SOUTH DAKOTA AND THE BLACK HILLS.
WARMER AIR WILL RETURN TO THE AREA THROUGH THE DAY AS WESTERLY
BOUNDARY LAYER FLOW STRENGTHENS ACROSS NORTHEAST WYOMING AND FAR
WESTERN SOUTH DAKOTA. HIGH TEMPERATURES WILL CLIMB INTO THE
40S...WITH SOME 30S LATE IN THE DAY ACROSS THE CENTRAL SOUTH
DAKOTA PLAINS. SOME WEAK ENERGY IN NORTHWEST FLOW LINGERS ACROSS
NORTHWEST SOUTH DAKOTA MONDAY NIGHT...WITH SOME LIGHT SNOW/SNOW
SHOWERS POSSIBLE. LOWS WILL BE IN THE TEENS TO LOWER 20S.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 324 AM MST SUN FEB 1 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA FROM TUESDAY
THROUGH SATURDAY. A RELATIVELY WEAK SHORTWAVE WILL BRING A CHANCE
OF SNOW OR RAIN TO NORTHEASTERN WYOMING AND NORTHWESTERN SOUTH
DAKOTA ON MONDAY. THERE WILL BE A BETTER CHANCE OF SNOW ACROSS
MUCH OF THE AREA ON TUESDAY AND TUESDAY NIGHT AS A BETTER DEFINED
UPPER TROUGH AND ASSOCIATED JET STREAK AFFECT THE AREA AS A COLD
FRONT MOVES THROUGH AT THE SURFACE. SNOW MAY LINGER INTO WEDNESDAY
ACROSS THE FAR SOUTHERN PARTS OF THE FORECAST AREA...BUT DRY
WEATHER IS THEN EXPECTED THROUGH THE REST OF THE WEEK AS THE UPPER
RIDGE OVER THE WESTERN CONUS BECOMES STRONGER. THERE IS A SLIGHT
CHANCE OF RAIN SHOWERS ON SATURDAY...AS THE UPPER RIDGE BEGINS TO
FLATTEN AND MID AND UPPER LEVEL TEMPERATURES COOL SLIGHTLY.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA. THERE WILL BE A WIDE
VARIATION IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS
TIME IT LOOKS LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER
THAN AVERAGE ON MONDAY AND TUESDAY...ESPECIALLY ACROSS THE
SOUTHWESTERN HALF OF THE CWA. BELOW NORMAL TEMPS ARE EXPECTED ON
WEDNESDAY AS THE BOUNDARY SHIFTS SOUTHWARD. WESTERLY WINDS WILL AID
IN SIGNIFICANT WARMING FOR THE END OF THE WEEK.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 324 AM MST SUN FEB 1 2015

MVFR CIGS WITH LCL IFR CIGS IN -SN WILL BE FOUND ACROSS MOST OF
THE AREA EARLY THIS MORNING. THE CIGS/VSBY WILL GRADUALLY IMPROVE
FROM NW-SE TODAY AS THE SNOW MOVES OFF TO THE EAST.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
     SDZ046-047-049.

WY...NONE.
&&

$$

SHORT TERM...15
LONG TERM...10
AVIATION...10






000
FXUS63 KUNR 011101
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
401 AM MST SUN FEB 1 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 324 AM MST SUN FEB 1 2015

UPPER LEVEL ANALYSIS HAS LARGE TROF ACROSS THE NORTH CENTRAL CONUS
WITH RIDGE ALONG THE WEST COAST. UPPER SHORTWAVE BRINGING SNOW TO
THE AREA AT THE MOMENT IS QUICKLY SHIFTING EAST WITH SKIES
CLEARING ACROSS EASTERN MONTANA. AT THE SURFACE...ARCTIC HIGH IS
SETTLING INTO THE NORTHERN PLAINS WITH WINDS MAINLY OUT OF THE
NORTH AT 5 TO 15 MPH. TEMPERATURES ARE MAINLY IN THE SINGLE
DIGITS.

TODAY...UPPER SHORTWAVE CONTINUES TO SHIFT QUICKLY EAST AS ARCTIC
HIGH PRESSURE SLIDES SOUTH THROUGH THE EASTERN DAKOTAS. LIGHT SNOW
WILL QUICKLY TAPER OFF EARLY THIS MORNING WITH SKIES BECOMING
PARTLY CLOUDY WEST TO EAST. TEMPERATURES WILL BE CHILLY...IN THE
TEENS ACROSS THE SD PLAINS...TO THE MID 20S IN NE WYOMING.
NORTHERLY WINDS WILL DIMINISH BY THE AFTERNOON.

TONIGHT...UPPER FLOW REMAINS NORTHWEST WITH BROAD RIDGE ACROSS THE
WESTERN CONUS. VARIABLY CLOUDY SKIES EXPECTED WITH TEMPERATURES
DROPPING OFF QUICKLY IN THE EVENING. LOWS WILL MAINLY BE IN THE
SINGLE DIGITS...WITH SOME BELOW ZERO TEMPS POSSIBLE ACROSS SOUTH
CENTRAL SOUTH DAKOTA.

MONDAY...NEXT UPPER SHORTWAVE IN NORTHWEST FLOW WILL GRAZE
NORTHERN PORTIONS OF THE FORECAST AREA...BRINGING SOME LIGHT RAIN
OR SNOW SHOWERS TO NORTHWEST SOUTH DAKOTA AND THE BLACK HILLS.
WARMER AIR WILL RETURN TO THE AREA THROUGH THE DAY AS WESTERLY
BOUNDARY LAYER FLOW STRENGTHENS ACROSS NORTHEAST WYOMING AND FAR
WESTERN SOUTH DAKOTA. HIGH TEMPERATURES WILL CLIMB INTO THE
40S...WITH SOME 30S LATE IN THE DAY ACROSS THE CENTRAL SOUTH
DAKOTA PLAINS. SOME WEAK ENERGY IN NORTHWEST FLOW LINGERS ACROSS
NORTHWEST SOUTH DAKOTA MONDAY NIGHT...WITH SOME LIGHT SNOW/SNOW
SHOWERS POSSIBLE. LOWS WILL BE IN THE TEENS TO LOWER 20S.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 324 AM MST SUN FEB 1 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA FROM TUESDAY
THROUGH SATURDAY. A RELATIVELY WEAK SHORTWAVE WILL BRING A CHANCE
OF SNOW OR RAIN TO NORTHEASTERN WYOMING AND NORTHWESTERN SOUTH
DAKOTA ON MONDAY. THERE WILL BE A BETTER CHANCE OF SNOW ACROSS
MUCH OF THE AREA ON TUESDAY AND TUESDAY NIGHT AS A BETTER DEFINED
UPPER TROUGH AND ASSOCIATED JET STREAK AFFECT THE AREA AS A COLD
FRONT MOVES THROUGH AT THE SURFACE. SNOW MAY LINGER INTO WEDNESDAY
ACROSS THE FAR SOUTHERN PARTS OF THE FORECAST AREA...BUT DRY
WEATHER IS THEN EXPECTED THROUGH THE REST OF THE WEEK AS THE UPPER
RIDGE OVER THE WESTERN CONUS BECOMES STRONGER. THERE IS A SLIGHT
CHANCE OF RAIN SHOWERS ON SATURDAY...AS THE UPPER RIDGE BEGINS TO
FLATTEN AND MID AND UPPER LEVEL TEMPERATURES COOL SLIGHTLY.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA. THERE WILL BE A WIDE
VARIATION IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS
TIME IT LOOKS LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER
THAN AVERAGE ON MONDAY AND TUESDAY...ESPECIALLY ACROSS THE
SOUTHWESTERN HALF OF THE CWA. BELOW NORMAL TEMPS ARE EXPECTED ON
WEDNESDAY AS THE BOUNDARY SHIFTS SOUTHWARD. WESTERLY WINDS WILL AID
IN SIGNIFICANT WARMING FOR THE END OF THE WEEK.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 324 AM MST SUN FEB 1 2015

MVFR CIGS WITH LCL IFR CIGS IN -SN WILL BE FOUND ACROSS MOST OF
THE AREA EARLY THIS MORNING. THE CIGS/VSBY WILL GRADUALLY IMPROVE
FROM NW-SE TODAY AS THE SNOW MOVES OFF TO THE EAST.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST EARLY THIS MORNING FOR
     SDZ046-047-049.

WY...NONE.
&&

$$

SHORT TERM...15
LONG TERM...10
AVIATION...10






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000
FXUS65 KRIW 011010
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
310 AM MST SUN FEB 1 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

THE NORTHERN STREAM SHORTWAVE IS NOW MAKING ITS WAY ACROSS
NORTHERN AND EASTERN WY AND HAS DRIVEN A COLD FRONT SOUTH TO THE
CONTINENTAL DIVIDE. THE INITIAL SHOT OF SNOWFALL FROM THE ASCT
COLD FRONT WAS A QUICK HITTER...AFFECTING AREAS MAINLY EAST AND
NORTH OF RIVERTON. BEHIND THE FRONT...NARROW NORTHWEST SOUTHEAST
ORIENTED SNOW BANDS HAVE SET UP WITH THE MOST PROMINENT ONE
SITUATED OVER CAMPBELL CORNER BETWEEN RIVERTON AND SHOSHONI AT THE
TIME OF THIS WRITING. NVA BEHIND THIS WEATHER FEATURE WILL PUSH
THE CLOUDS AND SNOWFALL OFF TO THE EAST LATER THIS MORNING. HIGH
TEMPERATURES TODAY BEHIND THE COLD FRONT WILL COOL DOWN THE MOST
FROM SATURDAYS HIGHS IN JOHNSON COUNTY WHICH IS IN THE MOST DIRECT
PATH OF THE COLD AIR ADVECTION. HIGH TEMPS WILL LIKELY REMAIN IN
THE UPPER 20S AT THE LOWER ELEVATIONS THERE TODAY. EXCEPT FOR MUCH
OF SWEETWATER COUNTY...ALMOST ALL AREAS EAST AND WEST OF THE
DIVIDE WILL REMAIN BELOW FREEZING TODAY. MOSTLY SUNNY SKIES ARE
EXPECTED BY LATE MORNING EAST OF THE DIVIDE TODAY. THE RIDGE THAT
IS AMPLIFIED ALONG THE PACIFIC COAST WILL FLATTEN CONSIDERABLY BY
THE TIME IT REACHES THE ROCKIES LATER TODAY. THE CIRCULATION OVER
45N/145W WILL EJECT A PACIFIC SHORTWAVE THAT WILL WEAKEN AS IT
RIDES UP AND OVER THE FLATTENED RIDGE AND APPROACHES WYOMING FROM
THE WEST NORTHWEST AS THE UPPER FLOW BACKS TO A MORE DIRECT FLOW
OFF THE PACIFIC. THIS WILL RESULT IN MAINLY LIGHT SNOWFALL
BREAKING OUT IN FAR WESTERN WY TONIGHT. THE SNOWFALL WILL TAPER
OFF IN THE FAR WEST LATER MONDAY BEFORE MORE SIGNIFICANT SNOWFALL
ARRIVES MONDAY NIGHT WITH THE POTENTIAL FOR SIGNIFICANT SNOWFALL
ACCUMULATION WITH SOME OF IT SPREADING INTO SWEETWATER COUNTY.
THEN AFTER A SHORT RESPITE FROM THE FAR WESTERN WY SNOWFALL
TUESDAY ALONG WITH A POSSIBLE BRIEF MIXTURE OF RAIN IN THE LOWER
ELEVATIONS...MORE SIGNIFICANT SNOWFALL IS EXPECTED TUESDAY NIGHT
WITH A MORE ROBUST SHORTWAVE ALONG WITH ADDITIONAL ISENTROPIC
LIFT. THIS ISENTROPIC LIFT WILL LIKELY SPREAD INTO SWEETWATER
COUNTY WITH LIGHT SNOW SPREADING INTO SWEETWATER COUNTY ONCE
AGAIN. A COLD FRONT WILL BE ASSOCIATED WITH THIS TUESDAY NIGHT
FEATURE AND WILL HELP SPREAD SOME SNOWFALL TO AREAS EAST OF THE
DIVIDE LATE TUESDAY NIGHT ALONG WITH SOME WEAK Q VECTOR FORCING.
OVERALL...MONDAY AND TUESDAY WILL FEATURE SEASONABLY MILD
CONDITIONS WITH THE WARMEST TEMPERATURES EXPECTED EAST OF THE
DIVIDE WITH DOWNSLOPE FLOW. AS FOR WIND...THE GRADIENT DOES NOT
DIRECTLY INDICATE HIGH WIND EARLY NEXT WEEK BUT H7 WINDS DO
INCREASE TO 50 KNOTS ON TUESDAY SO THE SOUTHERN WIND CORRIDOR AND
THE HIGHER ELEVATIONS WILL PROBABLY SEE THE HIGHEST WINDS TUESDAY
BUT BREEZY CONDITIONS WILL PERSIST IN THESE AREAS MONDAY THROUGH
TUESDAY NIGHT. THE FROUDE NUMBER IS SLATED TO BE AROUND ONE
TUESDAY NIGHT AROUND CLARK SO THAT AREA COULD SEE THE STRONGER
WINDS DURING THAT PERIOD.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

ACTIVE START TO THE MEDIUM RANGE PERIOD WITH EXPECTED MOIST WNW FLOW
AND SHORTWAVE INTERACTING WITH A STRONG COLD FRONT EAST OF THE
DIVIDE. COULD SEE A DECENT BAND OF SNOW ALONG AND BEHIND THE FRONT
WHERE THE FORCING ALOFT INTERSECT THIS FRONT. INCREASED POPS TO AT
LEAST CHANCE IN THE LOWER ELEVATIONS OF CENTRAL WYO THROUGH AT LEAST
THE MORNING BEFORE SOME IMPROVEMENT LATE. LOWERED HIGHS ALSO BEHIND
THIS FRONT. BRIEF RIDGING THURSDAY BEFORE FLOW STARTS TO FLATTEN
WITH STRONG...MOIST WLY FLOW DEVELOPING FOR FRIDAY THROUGH THE
WEEKEND...ESPECIALLY WITH THE GFS SOLUTION. THE ECMWF HAS MORE
RIDGING SUNDAY FOR A DRY AND MILD DAY WITH PCPN NOT RETURNING UNTIL
NEXT MONDAY MORNING. STUCK WITH THE MODEL BLEND WHICH SHOWS
INCREASING CHANCES OF MTN SNOW OUT WEST AGAIN NEXT SUNDAY NIGHT.
SO GOING WITH INCREASE POPS FRIDAY NIGHT CONTINUING THROUGH SATURDAY
WITH A POTENTIAL BREAK SATURDAY NIGHT INTO SUNDAY BEFORE ANOTHER
ROUND HITS SOMETIME SUNDAY OR SUNDAY NIGHT. THE MAIN WEATHER EAST OF
THE DIVIDE FOR MUCH OF THIS PERIOD WILL BE MILD EARLY FEBRUARY
TEMPERATURES WITH CONSIDERABLE WIND. POTENTIAL FOR SOME HIGH WINDS
IN THE WIND CORRIDOR FRIDAY THROUGH SUNDAY AND ALONG THE CODY
FOOTHILLS. H7 TEMPS LOOKS TO BE ABOVE 0C FRIDAY AND AGAIN SUNDAY
WITH A BRIEF COOLDOWN SATURDAY BEHIND OUR SAT SHORTWAVE THAT
PRODUCES ALL THE SNOW IN THE WRN MTNS BEFORE WARMING AGAIN SUNDAY.
ENOUGH GRADIENT AND WARM AIR ALOFT TO MIX MUCH OF THE AREA PRODUCING
HIGHS IN THE 40S AND 50S FOR MUCH OF THE LATTER HALF OF THE
EXTENDED. COLDEST DAY WILL BE WEDNESDAY WITH A CHILLY START TO
THURSDAY THEN CONSIDERABLY WARMER ON FRIDAY. MOST LIKELY A LITTLE
DROP SATURDAY THEN WARMER AGAIN NEXT SUNDAY.

&&

.AVIATION.../12Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

AREAS OF MVFR...LCL IFR CIGS AND MTN OBSCURATIONS WILL LINGER OVER
MUCH OF THE AREA THROUGH AROUND 14Z...ESPECIALLY ALONG THE EAST
SLOPES OF THE DIVIDE...AND NORTH FACING SLOPES.  THESE CIGS WILL
DISSIPATE LEAVING PREVAILING VFR CONDITIONS BY 18Z TODAY AND
THROUGH THE REST OF THE PERIOD. SOUTHWEST WINDS WILL PICK UP
THROUGH THE WIND CORRIDOR KRKS-KCPR AND ALONG THE EASTERN
FOOTHILLS OF THE DIVIDE LATE THIS AFTERNOON THROUGH SUNDAY NIGHT.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

PATCHY FOG WILL PARTIALLY OBSCURE TERRAIN OVER THE FAR WEST VALLEYS
THROUGH 15Z WITH FOG MORE WIDESPREAD ACROSS THE STAR VALLEY...VCNTY
KAFO.  SOME LOWER MVFR/IFR CIGS WILL ALSO BE ENCOUNTERED VCNTY AND
NE-E OF KRKS THROUGH AROUND 15Z.  VFR CONDITIONS WILL PREVAIL
ACROSS THE AREA BY 18Z TODAY. HOWEVER...CIGS ARE EXPECTED TO
LOWER ACROSS THE FAR WEST BY 00Z MONDAY WITH MVFR/IFR CIGS AND -SN
PREVAILING ACROSS MUCH OF THE WEST...VCNTY AND NORTH OF A KPNA-
KAFO LINE...BY 03Z MONDAY. LCL MVFR/IFR -SN WILL BE ENCOUNTERED
FURTHER SOUTH ALONG KBPI-KRKS ROUTES TONIGHT.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE THIS
MORNING. VALLEY FOG IS EXPECTED IN THE FAR WEST THIS MORNING. THEN
MOSTLY DRY THIS AFTERNOON THROUGH MONDAY EAST OF THE DIVIDE. WEST
OF THE DIVIDE WILL BE DRY THIS MORNING. LIGHT SNOW DEVELOPS OVER
THE NORTHWEST MOUNTAINS THIS AFTERNOON. PERIODS OF SNOW FOR THE
WESTERN MOUNTAINS AND FAR WEST VALLEYS TONIGHT THROUGH TUESDAY
NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON









000
FXUS65 KRIW 010655 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1149 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 242 PM MST)

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXCEPT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../06Z ISSUANCE/

SNOW...MAINLY CONVECTIVE SNOWBANDS IN THE VCNTY OF KRIW...WILL
MOSTLY END BY 09Z.  AREAS OF MVFR...LCL IFR CIGS AND MTN
OBSCURATIONS WILL LINGER OVER MUCH OF THE AREA THROUGH
14Z...ESPECIALLY ALONG THE EAST SLOPES OF THE DIVIDE...AND NORTH
FACING SLOPES.  THESE CIGS WILL DISSIPATE LEAVING PREVAILING VFR
CONDITIONS BY 18Z SUNDAY AND THROUGH THE REST OF THE PERIOD.
SOUTHWEST WINDS WILL PICK UP THROUGH THE WIND CORRIDOR KRKS-KCPR AND
ALONG THE EASTERN FOOTHILLS OF THE DIVIDE LATE SUNDAY AFTERNOON
THROUGH SUNDAY NIGHT.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

PATCHY FOG WILL FORM OVER THE FAR WEST VALLEYS OVERNIGHT WITH FOG
MORE WIDESPREAD ACROSS THE STAR VALLEY...VCNTY KAFO.  SOME LOWER
MVFR/IFR CIGS WILL ALSO BE ENCOUNTERED VCNTY AND NE-E OF KRKS
THROUGH AROUND 15Z SUNDAY.  VFR CONDITIONS WILL PREVAIL ACROSS THE
AREA BY 18Z SUNDAY.  HOWEVER...CIGS ARE EXPECTED TO LOWER ACROSS THE
FAR WEST BY 00Z MONDAY WITH MVFR/IFR CIGS AND -SN PREVAILING ACROSS
MUCH OF THE WEST...VCNTY AND NORTH OF A KPNA-KAFO LINE...BY 03Z
MONDAY.  LCL MVFR/IFR -SN WILL BE ENCOUNTERED FURTHER SOUTH ALONG
KBPI-KRKS ROUTES SUNDAY NIGHT.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AEM
FIRE WEATHER...AR











000
FXUS65 KRIW 010655 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1149 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 242 PM MST)

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXCEPT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../06Z ISSUANCE/

SNOW...MAINLY CONVECTIVE SNOWBANDS IN THE VCNTY OF KRIW...WILL
MOSTLY END BY 09Z.  AREAS OF MVFR...LCL IFR CIGS AND MTN
OBSCURATIONS WILL LINGER OVER MUCH OF THE AREA THROUGH
14Z...ESPECIALLY ALONG THE EAST SLOPES OF THE DIVIDE...AND NORTH
FACING SLOPES.  THESE CIGS WILL DISSIPATE LEAVING PREVAILING VFR
CONDITIONS BY 18Z SUNDAY AND THROUGH THE REST OF THE PERIOD.
SOUTHWEST WINDS WILL PICK UP THROUGH THE WIND CORRIDOR KRKS-KCPR AND
ALONG THE EASTERN FOOTHILLS OF THE DIVIDE LATE SUNDAY AFTERNOON
THROUGH SUNDAY NIGHT.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

PATCHY FOG WILL FORM OVER THE FAR WEST VALLEYS OVERNIGHT WITH FOG
MORE WIDESPREAD ACROSS THE STAR VALLEY...VCNTY KAFO.  SOME LOWER
MVFR/IFR CIGS WILL ALSO BE ENCOUNTERED VCNTY AND NE-E OF KRKS
THROUGH AROUND 15Z SUNDAY.  VFR CONDITIONS WILL PREVAIL ACROSS THE
AREA BY 18Z SUNDAY.  HOWEVER...CIGS ARE EXPECTED TO LOWER ACROSS THE
FAR WEST BY 00Z MONDAY WITH MVFR/IFR CIGS AND -SN PREVAILING ACROSS
MUCH OF THE WEST...VCNTY AND NORTH OF A KPNA-KAFO LINE...BY 03Z
MONDAY.  LCL MVFR/IFR -SN WILL BE ENCOUNTERED FURTHER SOUTH ALONG
KBPI-KRKS ROUTES SUNDAY NIGHT.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AEM
FIRE WEATHER...AR












000
FXUS65 KRIW 010655 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1149 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 242 PM MST)

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXCEPT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../06Z ISSUANCE/

SNOW...MAINLY CONVECTIVE SNOWBANDS IN THE VCNTY OF KRIW...WILL
MOSTLY END BY 09Z.  AREAS OF MVFR...LCL IFR CIGS AND MTN
OBSCURATIONS WILL LINGER OVER MUCH OF THE AREA THROUGH
14Z...ESPECIALLY ALONG THE EAST SLOPES OF THE DIVIDE...AND NORTH
FACING SLOPES.  THESE CIGS WILL DISSIPATE LEAVING PREVAILING VFR
CONDITIONS BY 18Z SUNDAY AND THROUGH THE REST OF THE PERIOD.
SOUTHWEST WINDS WILL PICK UP THROUGH THE WIND CORRIDOR KRKS-KCPR AND
ALONG THE EASTERN FOOTHILLS OF THE DIVIDE LATE SUNDAY AFTERNOON
THROUGH SUNDAY NIGHT.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

PATCHY FOG WILL FORM OVER THE FAR WEST VALLEYS OVERNIGHT WITH FOG
MORE WIDESPREAD ACROSS THE STAR VALLEY...VCNTY KAFO.  SOME LOWER
MVFR/IFR CIGS WILL ALSO BE ENCOUNTERED VCNTY AND NE-E OF KRKS
THROUGH AROUND 15Z SUNDAY.  VFR CONDITIONS WILL PREVAIL ACROSS THE
AREA BY 18Z SUNDAY.  HOWEVER...CIGS ARE EXPECTED TO LOWER ACROSS THE
FAR WEST BY 00Z MONDAY WITH MVFR/IFR CIGS AND -SN PREVAILING ACROSS
MUCH OF THE WEST...VCNTY AND NORTH OF A KPNA-KAFO LINE...BY 03Z
MONDAY.  LCL MVFR/IFR -SN WILL BE ENCOUNTERED FURTHER SOUTH ALONG
KBPI-KRKS ROUTES SUNDAY NIGHT.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AEM
FIRE WEATHER...AR










  [top]

000
FXUS65 KCYS 010556
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1056 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 756 PM MST SAT JAN 31 2015

SOUTHERN STREAM DISTURBANCE CONTINUES TO PUSH NORTHEAST AND
OUT OF THE AREA. SNOW HAS GENERALLY ENDED ACROSS THE NEBRASKA
PANHANDLE A SUBSIDENCE SETS IN BEHIND THIS DISTURBANCE...HOWEVER A
COLD FRONT AND NORTHERN STREAM DISTURBANCE IS QUICKLY FOLLOWING
AS IS MOVES INTO THE FORECAST AREA. SNOW SHOWERS ALREADY
DEVELOPING OVER SOUTHEAST WYOMING AND WILL QUICKLY SPREAD INTO THE
PANHANDLE THIS EVENING. MAINLY LOOKING FOR SCATTERED SNOW SHOWERS
TONIGHT WITH VERY LITTLE IN THE WAY OF SNOW ACCUMULATION. COULD
SEE AN INCH OR SO OF SNOW IN A FEW LOCATIONS BUT WILL BE ABOUT IT.
SNOW WILL MOSTLY END BY SUNRISE SUNDAY AS THE DISTURBANCE QUICKLY
MOVES SOUTHEAST INTO THE PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1049 PM MST SAT JAN 31 2015

FAST MOVING UPPER LEVEL DISTURBANCE WILL PRODUCE SNOW SHOWERS OVER
MUCH OF SOUTHEAST WYOMING AND THE NEBRASKA PANHANDLE TONIGHT BUT
THE MAIN AVIATION CONCERN IS THE LOW CLOUDS. ALONG AND EAST OF THE
LARAMIE RANGE INTO THE NEBRASKA PANHANDLE IFR TO MVFR CIGS WILL BE
IN PLACE TONIGHT. SKIES WILL CLEAR FROM WEST TO EAST MAINLY SUNDAY
MORNING.

&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH




000
FXUS65 KCYS 010556
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1056 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 756 PM MST SAT JAN 31 2015

SOUTHERN STREAM DISTURBANCE CONTINUES TO PUSH NORTHEAST AND
OUT OF THE AREA. SNOW HAS GENERALLY ENDED ACROSS THE NEBRASKA
PANHANDLE A SUBSIDENCE SETS IN BEHIND THIS DISTURBANCE...HOWEVER A
COLD FRONT AND NORTHERN STREAM DISTURBANCE IS QUICKLY FOLLOWING
AS IS MOVES INTO THE FORECAST AREA. SNOW SHOWERS ALREADY
DEVELOPING OVER SOUTHEAST WYOMING AND WILL QUICKLY SPREAD INTO THE
PANHANDLE THIS EVENING. MAINLY LOOKING FOR SCATTERED SNOW SHOWERS
TONIGHT WITH VERY LITTLE IN THE WAY OF SNOW ACCUMULATION. COULD
SEE AN INCH OR SO OF SNOW IN A FEW LOCATIONS BUT WILL BE ABOUT IT.
SNOW WILL MOSTLY END BY SUNRISE SUNDAY AS THE DISTURBANCE QUICKLY
MOVES SOUTHEAST INTO THE PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1049 PM MST SAT JAN 31 2015

FAST MOVING UPPER LEVEL DISTURBANCE WILL PRODUCE SNOW SHOWERS OVER
MUCH OF SOUTHEAST WYOMING AND THE NEBRASKA PANHANDLE TONIGHT BUT
THE MAIN AVIATION CONCERN IS THE LOW CLOUDS. ALONG AND EAST OF THE
LARAMIE RANGE INTO THE NEBRASKA PANHANDLE IFR TO MVFR CIGS WILL BE
IN PLACE TONIGHT. SKIES WILL CLEAR FROM WEST TO EAST MAINLY SUNDAY
MORNING.

&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH




000
FXUS65 KCYS 010556
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1056 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 756 PM MST SAT JAN 31 2015

SOUTHERN STREAM DISTURBANCE CONTINUES TO PUSH NORTHEAST AND
OUT OF THE AREA. SNOW HAS GENERALLY ENDED ACROSS THE NEBRASKA
PANHANDLE A SUBSIDENCE SETS IN BEHIND THIS DISTURBANCE...HOWEVER A
COLD FRONT AND NORTHERN STREAM DISTURBANCE IS QUICKLY FOLLOWING
AS IS MOVES INTO THE FORECAST AREA. SNOW SHOWERS ALREADY
DEVELOPING OVER SOUTHEAST WYOMING AND WILL QUICKLY SPREAD INTO THE
PANHANDLE THIS EVENING. MAINLY LOOKING FOR SCATTERED SNOW SHOWERS
TONIGHT WITH VERY LITTLE IN THE WAY OF SNOW ACCUMULATION. COULD
SEE AN INCH OR SO OF SNOW IN A FEW LOCATIONS BUT WILL BE ABOUT IT.
SNOW WILL MOSTLY END BY SUNRISE SUNDAY AS THE DISTURBANCE QUICKLY
MOVES SOUTHEAST INTO THE PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1049 PM MST SAT JAN 31 2015

FAST MOVING UPPER LEVEL DISTURBANCE WILL PRODUCE SNOW SHOWERS OVER
MUCH OF SOUTHEAST WYOMING AND THE NEBRASKA PANHANDLE TONIGHT BUT
THE MAIN AVIATION CONCERN IS THE LOW CLOUDS. ALONG AND EAST OF THE
LARAMIE RANGE INTO THE NEBRASKA PANHANDLE IFR TO MVFR CIGS WILL BE
IN PLACE TONIGHT. SKIES WILL CLEAR FROM WEST TO EAST MAINLY SUNDAY
MORNING.

&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH




000
FXUS65 KCYS 010556
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1056 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 756 PM MST SAT JAN 31 2015

SOUTHERN STREAM DISTURBANCE CONTINUES TO PUSH NORTHEAST AND
OUT OF THE AREA. SNOW HAS GENERALLY ENDED ACROSS THE NEBRASKA
PANHANDLE A SUBSIDENCE SETS IN BEHIND THIS DISTURBANCE...HOWEVER A
COLD FRONT AND NORTHERN STREAM DISTURBANCE IS QUICKLY FOLLOWING
AS IS MOVES INTO THE FORECAST AREA. SNOW SHOWERS ALREADY
DEVELOPING OVER SOUTHEAST WYOMING AND WILL QUICKLY SPREAD INTO THE
PANHANDLE THIS EVENING. MAINLY LOOKING FOR SCATTERED SNOW SHOWERS
TONIGHT WITH VERY LITTLE IN THE WAY OF SNOW ACCUMULATION. COULD
SEE AN INCH OR SO OF SNOW IN A FEW LOCATIONS BUT WILL BE ABOUT IT.
SNOW WILL MOSTLY END BY SUNRISE SUNDAY AS THE DISTURBANCE QUICKLY
MOVES SOUTHEAST INTO THE PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1049 PM MST SAT JAN 31 2015

FAST MOVING UPPER LEVEL DISTURBANCE WILL PRODUCE SNOW SHOWERS OVER
MUCH OF SOUTHEAST WYOMING AND THE NEBRASKA PANHANDLE TONIGHT BUT
THE MAIN AVIATION CONCERN IS THE LOW CLOUDS. ALONG AND EAST OF THE
LARAMIE RANGE INTO THE NEBRASKA PANHANDLE IFR TO MVFR CIGS WILL BE
IN PLACE TONIGHT. SKIES WILL CLEAR FROM WEST TO EAST MAINLY SUNDAY
MORNING.

&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH




000
FXUS65 KCYS 010556
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1056 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 756 PM MST SAT JAN 31 2015

SOUTHERN STREAM DISTURBANCE CONTINUES TO PUSH NORTHEAST AND
OUT OF THE AREA. SNOW HAS GENERALLY ENDED ACROSS THE NEBRASKA
PANHANDLE A SUBSIDENCE SETS IN BEHIND THIS DISTURBANCE...HOWEVER A
COLD FRONT AND NORTHERN STREAM DISTURBANCE IS QUICKLY FOLLOWING
AS IS MOVES INTO THE FORECAST AREA. SNOW SHOWERS ALREADY
DEVELOPING OVER SOUTHEAST WYOMING AND WILL QUICKLY SPREAD INTO THE
PANHANDLE THIS EVENING. MAINLY LOOKING FOR SCATTERED SNOW SHOWERS
TONIGHT WITH VERY LITTLE IN THE WAY OF SNOW ACCUMULATION. COULD
SEE AN INCH OR SO OF SNOW IN A FEW LOCATIONS BUT WILL BE ABOUT IT.
SNOW WILL MOSTLY END BY SUNRISE SUNDAY AS THE DISTURBANCE QUICKLY
MOVES SOUTHEAST INTO THE PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1049 PM MST SAT JAN 31 2015

FAST MOVING UPPER LEVEL DISTURBANCE WILL PRODUCE SNOW SHOWERS OVER
MUCH OF SOUTHEAST WYOMING AND THE NEBRASKA PANHANDLE TONIGHT BUT
THE MAIN AVIATION CONCERN IS THE LOW CLOUDS. ALONG AND EAST OF THE
LARAMIE RANGE INTO THE NEBRASKA PANHANDLE IFR TO MVFR CIGS WILL BE
IN PLACE TONIGHT. SKIES WILL CLEAR FROM WEST TO EAST MAINLY SUNDAY
MORNING.

&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH




000
FXUS63 KUNR 010400
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
900 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 900 PM MST SAT JAN 31 2015

LATEST WATER VAPOUR LOOP SHOWED SHORTWAVE OVER SOUTHEAST MT AND
ANOTHER OVER CO...AND THEY ARE ON THEIR WAY TO PHASE EAST OF THE
CWA AND CREATE HAVOC. CLOSER TO HOME...SURFACE TROUGH AHEAD OF
NORTHERN STREAM SHORTWAVE WORKING ACROSS WESTERN SD WITH BAND OF
-SN ALLOWING -FZDZ TO END. WILL DROP ADVISORY ON SCHEDULE.

DEFORMATION ZONE SNOWS FROM SOUTHERN STREAM SHORTWAVE ON TRACK TO
AFFECT SOUTH CENTRAL SD OVERNIGHT WITH 2-5 INCHES OF
SNOW...LOCALLY HIGHER AMOUNTS SOUTHEAST IF KICR.

UPDATE ISSUED AT 426 PM MST SAT JAN 31 2015

LOSS OF SOLAR INSOLATION ABOVE ST/FG DECK IS ALLOWING FZDZ TO
ACCUMULATE ON ROADS IN/NEAR THE BLACK HILLS...WHERE BEST UPSLOPE
ENHANCED FREEZING DRIZZLE/FOG ARE OCCURRING. HAVE HOISTED AN
ADVISORY TO ACCOUNT.

ACTIVITY SHOULD QUICKLY TURN TO SNOW AS TROUGH CURRENTLY ACROSS
SOUTHWEST ND INTO CENTRAL WY SWEEPS ACROSS THE CWA EARLY THIS
EVENING.

&&

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 148 PM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS. PHASING
NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL SUPPORT
CYCLOGENESIS ACROSS THE CENTRAL PLAINS...WITH A DEVELOPING
DEFORMATION ZONE NW OF THE LOW. THE FA WILL SEE INFLUENCE FROM
BOTH OF THESE SYSTEMS WITH THE NORTHERN COUNTERPART AFFECTING MOST
OF THE FA...WHILE SCENTRAL SD WILL SEE AN INFLUENCE FROM BOTH.
BACKDOOR COLD FRONT HAS SPREAD SW ACROSS THE FA...WITH FG AND
AREAS OF ZL IN ITS WAKE. EXPECTING FG AND ZL TO TAPPER OFF LATE
THIS AFTERNOON AND EARLY EVENING AS THERMAL PROFILES COOL AND ICE
NUCLEATION ENSUES. IN ADDITION...SEEDER FEEDER FROM DEVELOPING
SNOWS WILL ALSO SCOUR AVAILABLE NUCLEI. MAIN STORY WILL BE SNOWS
TONIGHT. STRONG UPPER JET STREAK ASSOCIATED WITH THE NORTHERN
STREAM SHORTWAVE WILL COMBINE WITH AN ASSOCIATED ARCTIC FRONT TO
SUPPORT SNOWS ACROSS MOST OF EH FA TONIGHT...SPREADING QUICKLY SE
FROM NW SD THIS EVENING. MUCH OF WESTERN SD AND PORTIONS OF NE WY
WILL SEE AROUND AN INCH TO 2 INCHES OF SNOW...POSSIBLY NEAR 3 IN
THE FAR NE NEAR LEMMON. THE NORTHERN BLACK HILLS AND FOOTHILLS
WILL ALSO SEE SOME UPSLOPE ENHANCEMENT...WITH CLOSER TO 3 INCHES
POSSIBLE THERE. MOST OF THE SNOW WILL FALL THIS EVENING...WITH
RESIDUAL LIGHT SNOW THE REMAINDER OF THE NIGHT.

A LITTLE DIFFERENT PROCESS EXPECTED OVER SCENTRAL SD. MASSIVE SW
CONUS UPPER LOW WILL EJECT INTO THE CENTRAL PLAINS AND CONTINUE TO
SUPPORT VIGOROUS CYCLOGENESIS IN THE EASTERN CENTRAL PLAINS AND
MIDWEST. MOIST CONVEYOR BELT ASSOCIATED WITH THIS PROCESS WILL
SUPPORT A STRENGTHENING DEFORMATION ZONE ACROSS CENTRAL NE INTO
SCENTRAL SD TONIGHT...WHERE LOCALLY ENHANCED SNOW RATES CAN BE
EXPECTED. IN ADDITION...PHASING NORTHERN STREAM IMPULSE WILL SUPPORT
A BRIEF STALL/PIVOT OF THE MOISTURE CONVEYOR BELT AND ASSOCIATED
DEFORMATION ZONE/FGEN...SUPPORTING A 2-4 HOUR EXTENSION OF DECENT
SNOWFALL. BOTTOM LINE EXPECTING 2-5 INCHES ACROSS MELLETTE...TODD
AND ESP TRIPP COUNTIES. LOCALLY HIGHER AMOUNTS COULD BE POSSIBLE IF
THE ENTIRE PROCESS SHIFTS A BIT FARTHER NW AND PAUSES LONGER. SNOW
WILL WIND DOWN QUICKLY SUNDAY MORNING WITH CLEARING SUNDAY AFTERNOON
MOST IF NOT ALL PLACES. A BRIEF SKIRT OF ARCTIC AIR WILL SUPPORT
MUCH COLDER TEMPERATURES ACROSS THE FA THROUGH SUNDAY. ACTIVE NW FLOW
WILL PERSIST WITH A LL BAROCLINIC ZONE REMAINING ACROSS THE FA. THE
NEXT IN A SERIES OF IMPULSES WILL ARRIVE LATE SUNDAY NIGHT...AND MAY
SUPPORT SNOW TOWARD DAWN MONDAY ACROSS THE FAR NW.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD. A RELATIVELY WEAK SHORTWAVE WILL BRING A
CHANCE OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY.
A BETTER DEFINED UPPER TROUGH/JET STREAK WILL AFFECT THE AREA ON
TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH AT THE
SURFACE...BRINGING A CHANCE OF SNOW TO THE AREA. AT THIS TIME IT
LOOKS LIKE THE BEST AREA FOR MEASURABLE SNOW ACCUMULATION WOULD BE
OVER PARTS OF NORTHEASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA.
SNOW MAY LINGER INTO WEDNESDAY ACROSS THE SOUTHWESTERN CWA...BUT
DRY WEATHER IS THEN EXPECTED THROUGH THE REST OF THE WEEK AS A
RIDGE BUILDS OVER THE WESTERN CONUS.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...ESPECIALLY ACROSS THE SOUTHWEST HALF OF THE
CWA. BELOW NORMAL TEMPS ARE EXPECTED ON WEDNESDAY AS THE BOUNDARY
SHIFTS SOUTH. WESTERLY WINDS WILL AID IN SIGNIFICANT WARMING FOR THE
END OF THE WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 900 PM MST SAT JAN 31 2015

WIDESPREAD IFR CONDITIONS DUE TO -SN/BR WILL IMPROVE FROM
NORTHWEST TO SOUTHEAST OVERNIGHT INTO SUNDAY. LOCAL LIFR
CONDITIONS WITH HEAVIEST BANDS OF SNOW...ESPECIALLY FROM ABOUT
MARTIN TO CHAMBERLAIN AND POINTS EAST.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR SDZ046-047-049.
WY...NONE.

&&

$$

UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...HELGESON




000
FXUS63 KUNR 010400
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
900 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 900 PM MST SAT JAN 31 2015

LATEST WATER VAPOUR LOOP SHOWED SHORTWAVE OVER SOUTHEAST MT AND
ANOTHER OVER CO...AND THEY ARE ON THEIR WAY TO PHASE EAST OF THE
CWA AND CREATE HAVOC. CLOSER TO HOME...SURFACE TROUGH AHEAD OF
NORTHERN STREAM SHORTWAVE WORKING ACROSS WESTERN SD WITH BAND OF
-SN ALLOWING -FZDZ TO END. WILL DROP ADVISORY ON SCHEDULE.

DEFORMATION ZONE SNOWS FROM SOUTHERN STREAM SHORTWAVE ON TRACK TO
AFFECT SOUTH CENTRAL SD OVERNIGHT WITH 2-5 INCHES OF
SNOW...LOCALLY HIGHER AMOUNTS SOUTHEAST IF KICR.

UPDATE ISSUED AT 426 PM MST SAT JAN 31 2015

LOSS OF SOLAR INSOLATION ABOVE ST/FG DECK IS ALLOWING FZDZ TO
ACCUMULATE ON ROADS IN/NEAR THE BLACK HILLS...WHERE BEST UPSLOPE
ENHANCED FREEZING DRIZZLE/FOG ARE OCCURRING. HAVE HOISTED AN
ADVISORY TO ACCOUNT.

ACTIVITY SHOULD QUICKLY TURN TO SNOW AS TROUGH CURRENTLY ACROSS
SOUTHWEST ND INTO CENTRAL WY SWEEPS ACROSS THE CWA EARLY THIS
EVENING.

&&

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 148 PM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS. PHASING
NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL SUPPORT
CYCLOGENESIS ACROSS THE CENTRAL PLAINS...WITH A DEVELOPING
DEFORMATION ZONE NW OF THE LOW. THE FA WILL SEE INFLUENCE FROM
BOTH OF THESE SYSTEMS WITH THE NORTHERN COUNTERPART AFFECTING MOST
OF THE FA...WHILE SCENTRAL SD WILL SEE AN INFLUENCE FROM BOTH.
BACKDOOR COLD FRONT HAS SPREAD SW ACROSS THE FA...WITH FG AND
AREAS OF ZL IN ITS WAKE. EXPECTING FG AND ZL TO TAPPER OFF LATE
THIS AFTERNOON AND EARLY EVENING AS THERMAL PROFILES COOL AND ICE
NUCLEATION ENSUES. IN ADDITION...SEEDER FEEDER FROM DEVELOPING
SNOWS WILL ALSO SCOUR AVAILABLE NUCLEI. MAIN STORY WILL BE SNOWS
TONIGHT. STRONG UPPER JET STREAK ASSOCIATED WITH THE NORTHERN
STREAM SHORTWAVE WILL COMBINE WITH AN ASSOCIATED ARCTIC FRONT TO
SUPPORT SNOWS ACROSS MOST OF EH FA TONIGHT...SPREADING QUICKLY SE
FROM NW SD THIS EVENING. MUCH OF WESTERN SD AND PORTIONS OF NE WY
WILL SEE AROUND AN INCH TO 2 INCHES OF SNOW...POSSIBLY NEAR 3 IN
THE FAR NE NEAR LEMMON. THE NORTHERN BLACK HILLS AND FOOTHILLS
WILL ALSO SEE SOME UPSLOPE ENHANCEMENT...WITH CLOSER TO 3 INCHES
POSSIBLE THERE. MOST OF THE SNOW WILL FALL THIS EVENING...WITH
RESIDUAL LIGHT SNOW THE REMAINDER OF THE NIGHT.

A LITTLE DIFFERENT PROCESS EXPECTED OVER SCENTRAL SD. MASSIVE SW
CONUS UPPER LOW WILL EJECT INTO THE CENTRAL PLAINS AND CONTINUE TO
SUPPORT VIGOROUS CYCLOGENESIS IN THE EASTERN CENTRAL PLAINS AND
MIDWEST. MOIST CONVEYOR BELT ASSOCIATED WITH THIS PROCESS WILL
SUPPORT A STRENGTHENING DEFORMATION ZONE ACROSS CENTRAL NE INTO
SCENTRAL SD TONIGHT...WHERE LOCALLY ENHANCED SNOW RATES CAN BE
EXPECTED. IN ADDITION...PHASING NORTHERN STREAM IMPULSE WILL SUPPORT
A BRIEF STALL/PIVOT OF THE MOISTURE CONVEYOR BELT AND ASSOCIATED
DEFORMATION ZONE/FGEN...SUPPORTING A 2-4 HOUR EXTENSION OF DECENT
SNOWFALL. BOTTOM LINE EXPECTING 2-5 INCHES ACROSS MELLETTE...TODD
AND ESP TRIPP COUNTIES. LOCALLY HIGHER AMOUNTS COULD BE POSSIBLE IF
THE ENTIRE PROCESS SHIFTS A BIT FARTHER NW AND PAUSES LONGER. SNOW
WILL WIND DOWN QUICKLY SUNDAY MORNING WITH CLEARING SUNDAY AFTERNOON
MOST IF NOT ALL PLACES. A BRIEF SKIRT OF ARCTIC AIR WILL SUPPORT
MUCH COLDER TEMPERATURES ACROSS THE FA THROUGH SUNDAY. ACTIVE NW FLOW
WILL PERSIST WITH A LL BAROCLINIC ZONE REMAINING ACROSS THE FA. THE
NEXT IN A SERIES OF IMPULSES WILL ARRIVE LATE SUNDAY NIGHT...AND MAY
SUPPORT SNOW TOWARD DAWN MONDAY ACROSS THE FAR NW.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD. A RELATIVELY WEAK SHORTWAVE WILL BRING A
CHANCE OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY.
A BETTER DEFINED UPPER TROUGH/JET STREAK WILL AFFECT THE AREA ON
TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH AT THE
SURFACE...BRINGING A CHANCE OF SNOW TO THE AREA. AT THIS TIME IT
LOOKS LIKE THE BEST AREA FOR MEASURABLE SNOW ACCUMULATION WOULD BE
OVER PARTS OF NORTHEASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA.
SNOW MAY LINGER INTO WEDNESDAY ACROSS THE SOUTHWESTERN CWA...BUT
DRY WEATHER IS THEN EXPECTED THROUGH THE REST OF THE WEEK AS A
RIDGE BUILDS OVER THE WESTERN CONUS.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...ESPECIALLY ACROSS THE SOUTHWEST HALF OF THE
CWA. BELOW NORMAL TEMPS ARE EXPECTED ON WEDNESDAY AS THE BOUNDARY
SHIFTS SOUTH. WESTERLY WINDS WILL AID IN SIGNIFICANT WARMING FOR THE
END OF THE WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 900 PM MST SAT JAN 31 2015

WIDESPREAD IFR CONDITIONS DUE TO -SN/BR WILL IMPROVE FROM
NORTHWEST TO SOUTHEAST OVERNIGHT INTO SUNDAY. LOCAL LIFR
CONDITIONS WITH HEAVIEST BANDS OF SNOW...ESPECIALLY FROM ABOUT
MARTIN TO CHAMBERLAIN AND POINTS EAST.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR SDZ046-047-049.
WY...NONE.

&&

$$

UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...HELGESON




000
FXUS63 KUNR 010400
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
900 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 900 PM MST SAT JAN 31 2015

LATEST WATER VAPOUR LOOP SHOWED SHORTWAVE OVER SOUTHEAST MT AND
ANOTHER OVER CO...AND THEY ARE ON THEIR WAY TO PHASE EAST OF THE
CWA AND CREATE HAVOC. CLOSER TO HOME...SURFACE TROUGH AHEAD OF
NORTHERN STREAM SHORTWAVE WORKING ACROSS WESTERN SD WITH BAND OF
-SN ALLOWING -FZDZ TO END. WILL DROP ADVISORY ON SCHEDULE.

DEFORMATION ZONE SNOWS FROM SOUTHERN STREAM SHORTWAVE ON TRACK TO
AFFECT SOUTH CENTRAL SD OVERNIGHT WITH 2-5 INCHES OF
SNOW...LOCALLY HIGHER AMOUNTS SOUTHEAST IF KICR.

UPDATE ISSUED AT 426 PM MST SAT JAN 31 2015

LOSS OF SOLAR INSOLATION ABOVE ST/FG DECK IS ALLOWING FZDZ TO
ACCUMULATE ON ROADS IN/NEAR THE BLACK HILLS...WHERE BEST UPSLOPE
ENHANCED FREEZING DRIZZLE/FOG ARE OCCURRING. HAVE HOISTED AN
ADVISORY TO ACCOUNT.

ACTIVITY SHOULD QUICKLY TURN TO SNOW AS TROUGH CURRENTLY ACROSS
SOUTHWEST ND INTO CENTRAL WY SWEEPS ACROSS THE CWA EARLY THIS
EVENING.

&&

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 148 PM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS. PHASING
NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL SUPPORT
CYCLOGENESIS ACROSS THE CENTRAL PLAINS...WITH A DEVELOPING
DEFORMATION ZONE NW OF THE LOW. THE FA WILL SEE INFLUENCE FROM
BOTH OF THESE SYSTEMS WITH THE NORTHERN COUNTERPART AFFECTING MOST
OF THE FA...WHILE SCENTRAL SD WILL SEE AN INFLUENCE FROM BOTH.
BACKDOOR COLD FRONT HAS SPREAD SW ACROSS THE FA...WITH FG AND
AREAS OF ZL IN ITS WAKE. EXPECTING FG AND ZL TO TAPPER OFF LATE
THIS AFTERNOON AND EARLY EVENING AS THERMAL PROFILES COOL AND ICE
NUCLEATION ENSUES. IN ADDITION...SEEDER FEEDER FROM DEVELOPING
SNOWS WILL ALSO SCOUR AVAILABLE NUCLEI. MAIN STORY WILL BE SNOWS
TONIGHT. STRONG UPPER JET STREAK ASSOCIATED WITH THE NORTHERN
STREAM SHORTWAVE WILL COMBINE WITH AN ASSOCIATED ARCTIC FRONT TO
SUPPORT SNOWS ACROSS MOST OF EH FA TONIGHT...SPREADING QUICKLY SE
FROM NW SD THIS EVENING. MUCH OF WESTERN SD AND PORTIONS OF NE WY
WILL SEE AROUND AN INCH TO 2 INCHES OF SNOW...POSSIBLY NEAR 3 IN
THE FAR NE NEAR LEMMON. THE NORTHERN BLACK HILLS AND FOOTHILLS
WILL ALSO SEE SOME UPSLOPE ENHANCEMENT...WITH CLOSER TO 3 INCHES
POSSIBLE THERE. MOST OF THE SNOW WILL FALL THIS EVENING...WITH
RESIDUAL LIGHT SNOW THE REMAINDER OF THE NIGHT.

A LITTLE DIFFERENT PROCESS EXPECTED OVER SCENTRAL SD. MASSIVE SW
CONUS UPPER LOW WILL EJECT INTO THE CENTRAL PLAINS AND CONTINUE TO
SUPPORT VIGOROUS CYCLOGENESIS IN THE EASTERN CENTRAL PLAINS AND
MIDWEST. MOIST CONVEYOR BELT ASSOCIATED WITH THIS PROCESS WILL
SUPPORT A STRENGTHENING DEFORMATION ZONE ACROSS CENTRAL NE INTO
SCENTRAL SD TONIGHT...WHERE LOCALLY ENHANCED SNOW RATES CAN BE
EXPECTED. IN ADDITION...PHASING NORTHERN STREAM IMPULSE WILL SUPPORT
A BRIEF STALL/PIVOT OF THE MOISTURE CONVEYOR BELT AND ASSOCIATED
DEFORMATION ZONE/FGEN...SUPPORTING A 2-4 HOUR EXTENSION OF DECENT
SNOWFALL. BOTTOM LINE EXPECTING 2-5 INCHES ACROSS MELLETTE...TODD
AND ESP TRIPP COUNTIES. LOCALLY HIGHER AMOUNTS COULD BE POSSIBLE IF
THE ENTIRE PROCESS SHIFTS A BIT FARTHER NW AND PAUSES LONGER. SNOW
WILL WIND DOWN QUICKLY SUNDAY MORNING WITH CLEARING SUNDAY AFTERNOON
MOST IF NOT ALL PLACES. A BRIEF SKIRT OF ARCTIC AIR WILL SUPPORT
MUCH COLDER TEMPERATURES ACROSS THE FA THROUGH SUNDAY. ACTIVE NW FLOW
WILL PERSIST WITH A LL BAROCLINIC ZONE REMAINING ACROSS THE FA. THE
NEXT IN A SERIES OF IMPULSES WILL ARRIVE LATE SUNDAY NIGHT...AND MAY
SUPPORT SNOW TOWARD DAWN MONDAY ACROSS THE FAR NW.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD. A RELATIVELY WEAK SHORTWAVE WILL BRING A
CHANCE OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY.
A BETTER DEFINED UPPER TROUGH/JET STREAK WILL AFFECT THE AREA ON
TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH AT THE
SURFACE...BRINGING A CHANCE OF SNOW TO THE AREA. AT THIS TIME IT
LOOKS LIKE THE BEST AREA FOR MEASURABLE SNOW ACCUMULATION WOULD BE
OVER PARTS OF NORTHEASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA.
SNOW MAY LINGER INTO WEDNESDAY ACROSS THE SOUTHWESTERN CWA...BUT
DRY WEATHER IS THEN EXPECTED THROUGH THE REST OF THE WEEK AS A
RIDGE BUILDS OVER THE WESTERN CONUS.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...ESPECIALLY ACROSS THE SOUTHWEST HALF OF THE
CWA. BELOW NORMAL TEMPS ARE EXPECTED ON WEDNESDAY AS THE BOUNDARY
SHIFTS SOUTH. WESTERLY WINDS WILL AID IN SIGNIFICANT WARMING FOR THE
END OF THE WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 900 PM MST SAT JAN 31 2015

WIDESPREAD IFR CONDITIONS DUE TO -SN/BR WILL IMPROVE FROM
NORTHWEST TO SOUTHEAST OVERNIGHT INTO SUNDAY. LOCAL LIFR
CONDITIONS WITH HEAVIEST BANDS OF SNOW...ESPECIALLY FROM ABOUT
MARTIN TO CHAMBERLAIN AND POINTS EAST.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR SDZ046-047-049.
WY...NONE.

&&

$$

UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...HELGESON





000
FXUS63 KUNR 010400
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
900 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 900 PM MST SAT JAN 31 2015

LATEST WATER VAPOUR LOOP SHOWED SHORTWAVE OVER SOUTHEAST MT AND
ANOTHER OVER CO...AND THEY ARE ON THEIR WAY TO PHASE EAST OF THE
CWA AND CREATE HAVOC. CLOSER TO HOME...SURFACE TROUGH AHEAD OF
NORTHERN STREAM SHORTWAVE WORKING ACROSS WESTERN SD WITH BAND OF
-SN ALLOWING -FZDZ TO END. WILL DROP ADVISORY ON SCHEDULE.

DEFORMATION ZONE SNOWS FROM SOUTHERN STREAM SHORTWAVE ON TRACK TO
AFFECT SOUTH CENTRAL SD OVERNIGHT WITH 2-5 INCHES OF
SNOW...LOCALLY HIGHER AMOUNTS SOUTHEAST IF KICR.

UPDATE ISSUED AT 426 PM MST SAT JAN 31 2015

LOSS OF SOLAR INSOLATION ABOVE ST/FG DECK IS ALLOWING FZDZ TO
ACCUMULATE ON ROADS IN/NEAR THE BLACK HILLS...WHERE BEST UPSLOPE
ENHANCED FREEZING DRIZZLE/FOG ARE OCCURRING. HAVE HOISTED AN
ADVISORY TO ACCOUNT.

ACTIVITY SHOULD QUICKLY TURN TO SNOW AS TROUGH CURRENTLY ACROSS
SOUTHWEST ND INTO CENTRAL WY SWEEPS ACROSS THE CWA EARLY THIS
EVENING.

&&

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 148 PM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS. PHASING
NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL SUPPORT
CYCLOGENESIS ACROSS THE CENTRAL PLAINS...WITH A DEVELOPING
DEFORMATION ZONE NW OF THE LOW. THE FA WILL SEE INFLUENCE FROM
BOTH OF THESE SYSTEMS WITH THE NORTHERN COUNTERPART AFFECTING MOST
OF THE FA...WHILE SCENTRAL SD WILL SEE AN INFLUENCE FROM BOTH.
BACKDOOR COLD FRONT HAS SPREAD SW ACROSS THE FA...WITH FG AND
AREAS OF ZL IN ITS WAKE. EXPECTING FG AND ZL TO TAPPER OFF LATE
THIS AFTERNOON AND EARLY EVENING AS THERMAL PROFILES COOL AND ICE
NUCLEATION ENSUES. IN ADDITION...SEEDER FEEDER FROM DEVELOPING
SNOWS WILL ALSO SCOUR AVAILABLE NUCLEI. MAIN STORY WILL BE SNOWS
TONIGHT. STRONG UPPER JET STREAK ASSOCIATED WITH THE NORTHERN
STREAM SHORTWAVE WILL COMBINE WITH AN ASSOCIATED ARCTIC FRONT TO
SUPPORT SNOWS ACROSS MOST OF EH FA TONIGHT...SPREADING QUICKLY SE
FROM NW SD THIS EVENING. MUCH OF WESTERN SD AND PORTIONS OF NE WY
WILL SEE AROUND AN INCH TO 2 INCHES OF SNOW...POSSIBLY NEAR 3 IN
THE FAR NE NEAR LEMMON. THE NORTHERN BLACK HILLS AND FOOTHILLS
WILL ALSO SEE SOME UPSLOPE ENHANCEMENT...WITH CLOSER TO 3 INCHES
POSSIBLE THERE. MOST OF THE SNOW WILL FALL THIS EVENING...WITH
RESIDUAL LIGHT SNOW THE REMAINDER OF THE NIGHT.

A LITTLE DIFFERENT PROCESS EXPECTED OVER SCENTRAL SD. MASSIVE SW
CONUS UPPER LOW WILL EJECT INTO THE CENTRAL PLAINS AND CONTINUE TO
SUPPORT VIGOROUS CYCLOGENESIS IN THE EASTERN CENTRAL PLAINS AND
MIDWEST. MOIST CONVEYOR BELT ASSOCIATED WITH THIS PROCESS WILL
SUPPORT A STRENGTHENING DEFORMATION ZONE ACROSS CENTRAL NE INTO
SCENTRAL SD TONIGHT...WHERE LOCALLY ENHANCED SNOW RATES CAN BE
EXPECTED. IN ADDITION...PHASING NORTHERN STREAM IMPULSE WILL SUPPORT
A BRIEF STALL/PIVOT OF THE MOISTURE CONVEYOR BELT AND ASSOCIATED
DEFORMATION ZONE/FGEN...SUPPORTING A 2-4 HOUR EXTENSION OF DECENT
SNOWFALL. BOTTOM LINE EXPECTING 2-5 INCHES ACROSS MELLETTE...TODD
AND ESP TRIPP COUNTIES. LOCALLY HIGHER AMOUNTS COULD BE POSSIBLE IF
THE ENTIRE PROCESS SHIFTS A BIT FARTHER NW AND PAUSES LONGER. SNOW
WILL WIND DOWN QUICKLY SUNDAY MORNING WITH CLEARING SUNDAY AFTERNOON
MOST IF NOT ALL PLACES. A BRIEF SKIRT OF ARCTIC AIR WILL SUPPORT
MUCH COLDER TEMPERATURES ACROSS THE FA THROUGH SUNDAY. ACTIVE NW FLOW
WILL PERSIST WITH A LL BAROCLINIC ZONE REMAINING ACROSS THE FA. THE
NEXT IN A SERIES OF IMPULSES WILL ARRIVE LATE SUNDAY NIGHT...AND MAY
SUPPORT SNOW TOWARD DAWN MONDAY ACROSS THE FAR NW.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD. A RELATIVELY WEAK SHORTWAVE WILL BRING A
CHANCE OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY.
A BETTER DEFINED UPPER TROUGH/JET STREAK WILL AFFECT THE AREA ON
TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH AT THE
SURFACE...BRINGING A CHANCE OF SNOW TO THE AREA. AT THIS TIME IT
LOOKS LIKE THE BEST AREA FOR MEASURABLE SNOW ACCUMULATION WOULD BE
OVER PARTS OF NORTHEASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA.
SNOW MAY LINGER INTO WEDNESDAY ACROSS THE SOUTHWESTERN CWA...BUT
DRY WEATHER IS THEN EXPECTED THROUGH THE REST OF THE WEEK AS A
RIDGE BUILDS OVER THE WESTERN CONUS.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...ESPECIALLY ACROSS THE SOUTHWEST HALF OF THE
CWA. BELOW NORMAL TEMPS ARE EXPECTED ON WEDNESDAY AS THE BOUNDARY
SHIFTS SOUTH. WESTERLY WINDS WILL AID IN SIGNIFICANT WARMING FOR THE
END OF THE WEEK.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 900 PM MST SAT JAN 31 2015

WIDESPREAD IFR CONDITIONS DUE TO -SN/BR WILL IMPROVE FROM
NORTHWEST TO SOUTHEAST OVERNIGHT INTO SUNDAY. LOCAL LIFR
CONDITIONS WITH HEAVIEST BANDS OF SNOW...ESPECIALLY FROM ABOUT
MARTIN TO CHAMBERLAIN AND POINTS EAST.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR SDZ046-047-049.
WY...NONE.

&&

$$

UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...HELGESON





000
FXUS65 KCYS 010257
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
757 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 756 PM MST SAT JAN 31 2015

SOUTHERN STREAM DISTURBANCE CONTINUES TO PUSH NORTHEAST AND
OUT OF THE AREA. SNOW HAS GENERALLY ENDED ACROSS THE NEBRASKA
PANHANDLE A SUBSIDENCE SETS IN BEHIND THIS DISTURBANCE...HOWEVER A
COLD FRONT AND NORTHERN STREAM DISTURBANCE IS QUICKLY FOLLOWING
AS IS MOVES INTO THE FORECAST AREA. SNOW SHOWERS ALREADY
DEVELOPING OVER SOUTHEAST WYOMING AND WILL QUICKLY SPREAD INTO THE
PANHANDLE THIS EVENING. MAINLY LOOKING FOR SCATTERED SNOW SHOWERS
TONIGHT WITH VERY LITTLE IN THE WAY OF SNOW ACCUMULATION. COULD
SEE AN INCH OR SO OF SNOW IN A FEW LOCATIONS BUT WILL BE ABOUT IT.
SNOW WILL MOSTLY END BY SUNRISE SUNDAY AS THE DISTURBANCE QUICKLY
MOVES SOUTHEAST INTO THE PLAINS.


&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 514 PM MST SAT JAN 31 2015

TWO UPPER LEVEL DISTURBANCES AFFECTING THE AREA THIS EVENING. THE
FIRST UPPER DISTURBANCE IS NO EXITING THE NEBRASKA PANHANDLE. SNOW
WILL QUICKLY END EARLY THIS EVENING AS THIS DISTURBANCE EXITS BUT
THE NEXT NORTHERN STREAM DISTURBANCE WILL QUICKLY MOVE FROM NORTH
CENTRAL WYOMING EARLY THIS EVENING INTO SOUTHEAST WYOMING BY LATE
THIS EVENING. SNOW SHOWERS WILL DEVELOP ACROSS SOUTHEAST WYOMING
AND NEBRASKA PANHANDLE THIS EVENING WITH SNOW SHOWERS ENDING LATE
TONIGHT AS THE DISTURBANCE RAPIDLY MOVES THROUGH THE AREA. IFR TO
MVFR IS EXPECTED TONIGHT DUE TO LOW CLOUDS AND SNOW SHOWERS.
MOUNTAIN TOPS WILL BE OBSCURED AND MOUNTAINS MAY BE OBSCURED AT
TIMES.


&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH




000
FXUS65 KCYS 010257
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
757 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 756 PM MST SAT JAN 31 2015

SOUTHERN STREAM DISTURBANCE CONTINUES TO PUSH NORTHEAST AND
OUT OF THE AREA. SNOW HAS GENERALLY ENDED ACROSS THE NEBRASKA
PANHANDLE A SUBSIDENCE SETS IN BEHIND THIS DISTURBANCE...HOWEVER A
COLD FRONT AND NORTHERN STREAM DISTURBANCE IS QUICKLY FOLLOWING
AS IS MOVES INTO THE FORECAST AREA. SNOW SHOWERS ALREADY
DEVELOPING OVER SOUTHEAST WYOMING AND WILL QUICKLY SPREAD INTO THE
PANHANDLE THIS EVENING. MAINLY LOOKING FOR SCATTERED SNOW SHOWERS
TONIGHT WITH VERY LITTLE IN THE WAY OF SNOW ACCUMULATION. COULD
SEE AN INCH OR SO OF SNOW IN A FEW LOCATIONS BUT WILL BE ABOUT IT.
SNOW WILL MOSTLY END BY SUNRISE SUNDAY AS THE DISTURBANCE QUICKLY
MOVES SOUTHEAST INTO THE PLAINS.


&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 514 PM MST SAT JAN 31 2015

TWO UPPER LEVEL DISTURBANCES AFFECTING THE AREA THIS EVENING. THE
FIRST UPPER DISTURBANCE IS NO EXITING THE NEBRASKA PANHANDLE. SNOW
WILL QUICKLY END EARLY THIS EVENING AS THIS DISTURBANCE EXITS BUT
THE NEXT NORTHERN STREAM DISTURBANCE WILL QUICKLY MOVE FROM NORTH
CENTRAL WYOMING EARLY THIS EVENING INTO SOUTHEAST WYOMING BY LATE
THIS EVENING. SNOW SHOWERS WILL DEVELOP ACROSS SOUTHEAST WYOMING
AND NEBRASKA PANHANDLE THIS EVENING WITH SNOW SHOWERS ENDING LATE
TONIGHT AS THE DISTURBANCE RAPIDLY MOVES THROUGH THE AREA. IFR TO
MVFR IS EXPECTED TONIGHT DUE TO LOW CLOUDS AND SNOW SHOWERS.
MOUNTAIN TOPS WILL BE OBSCURED AND MOUNTAINS MAY BE OBSCURED AT
TIMES.


&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH



000
FXUS65 KCYS 010257
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
757 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 756 PM MST SAT JAN 31 2015

SOUTHERN STREAM DISTURBANCE CONTINUES TO PUSH NORTHEAST AND
OUT OF THE AREA. SNOW HAS GENERALLY ENDED ACROSS THE NEBRASKA
PANHANDLE A SUBSIDENCE SETS IN BEHIND THIS DISTURBANCE...HOWEVER A
COLD FRONT AND NORTHERN STREAM DISTURBANCE IS QUICKLY FOLLOWING
AS IS MOVES INTO THE FORECAST AREA. SNOW SHOWERS ALREADY
DEVELOPING OVER SOUTHEAST WYOMING AND WILL QUICKLY SPREAD INTO THE
PANHANDLE THIS EVENING. MAINLY LOOKING FOR SCATTERED SNOW SHOWERS
TONIGHT WITH VERY LITTLE IN THE WAY OF SNOW ACCUMULATION. COULD
SEE AN INCH OR SO OF SNOW IN A FEW LOCATIONS BUT WILL BE ABOUT IT.
SNOW WILL MOSTLY END BY SUNRISE SUNDAY AS THE DISTURBANCE QUICKLY
MOVES SOUTHEAST INTO THE PLAINS.


&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 514 PM MST SAT JAN 31 2015

TWO UPPER LEVEL DISTURBANCES AFFECTING THE AREA THIS EVENING. THE
FIRST UPPER DISTURBANCE IS NO EXITING THE NEBRASKA PANHANDLE. SNOW
WILL QUICKLY END EARLY THIS EVENING AS THIS DISTURBANCE EXITS BUT
THE NEXT NORTHERN STREAM DISTURBANCE WILL QUICKLY MOVE FROM NORTH
CENTRAL WYOMING EARLY THIS EVENING INTO SOUTHEAST WYOMING BY LATE
THIS EVENING. SNOW SHOWERS WILL DEVELOP ACROSS SOUTHEAST WYOMING
AND NEBRASKA PANHANDLE THIS EVENING WITH SNOW SHOWERS ENDING LATE
TONIGHT AS THE DISTURBANCE RAPIDLY MOVES THROUGH THE AREA. IFR TO
MVFR IS EXPECTED TONIGHT DUE TO LOW CLOUDS AND SNOW SHOWERS.
MOUNTAIN TOPS WILL BE OBSCURED AND MOUNTAINS MAY BE OBSCURED AT
TIMES.


&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH



000
FXUS65 KCYS 010257
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
757 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 756 PM MST SAT JAN 31 2015

SOUTHERN STREAM DISTURBANCE CONTINUES TO PUSH NORTHEAST AND
OUT OF THE AREA. SNOW HAS GENERALLY ENDED ACROSS THE NEBRASKA
PANHANDLE A SUBSIDENCE SETS IN BEHIND THIS DISTURBANCE...HOWEVER A
COLD FRONT AND NORTHERN STREAM DISTURBANCE IS QUICKLY FOLLOWING
AS IS MOVES INTO THE FORECAST AREA. SNOW SHOWERS ALREADY
DEVELOPING OVER SOUTHEAST WYOMING AND WILL QUICKLY SPREAD INTO THE
PANHANDLE THIS EVENING. MAINLY LOOKING FOR SCATTERED SNOW SHOWERS
TONIGHT WITH VERY LITTLE IN THE WAY OF SNOW ACCUMULATION. COULD
SEE AN INCH OR SO OF SNOW IN A FEW LOCATIONS BUT WILL BE ABOUT IT.
SNOW WILL MOSTLY END BY SUNRISE SUNDAY AS THE DISTURBANCE QUICKLY
MOVES SOUTHEAST INTO THE PLAINS.


&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 514 PM MST SAT JAN 31 2015

TWO UPPER LEVEL DISTURBANCES AFFECTING THE AREA THIS EVENING. THE
FIRST UPPER DISTURBANCE IS NO EXITING THE NEBRASKA PANHANDLE. SNOW
WILL QUICKLY END EARLY THIS EVENING AS THIS DISTURBANCE EXITS BUT
THE NEXT NORTHERN STREAM DISTURBANCE WILL QUICKLY MOVE FROM NORTH
CENTRAL WYOMING EARLY THIS EVENING INTO SOUTHEAST WYOMING BY LATE
THIS EVENING. SNOW SHOWERS WILL DEVELOP ACROSS SOUTHEAST WYOMING
AND NEBRASKA PANHANDLE THIS EVENING WITH SNOW SHOWERS ENDING LATE
TONIGHT AS THE DISTURBANCE RAPIDLY MOVES THROUGH THE AREA. IFR TO
MVFR IS EXPECTED TONIGHT DUE TO LOW CLOUDS AND SNOW SHOWERS.
MOUNTAIN TOPS WILL BE OBSCURED AND MOUNTAINS MAY BE OBSCURED AT
TIMES.


&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH



000
FXUS65 KCYS 010257
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
757 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 756 PM MST SAT JAN 31 2015

SOUTHERN STREAM DISTURBANCE CONTINUES TO PUSH NORTHEAST AND
OUT OF THE AREA. SNOW HAS GENERALLY ENDED ACROSS THE NEBRASKA
PANHANDLE A SUBSIDENCE SETS IN BEHIND THIS DISTURBANCE...HOWEVER A
COLD FRONT AND NORTHERN STREAM DISTURBANCE IS QUICKLY FOLLOWING
AS IS MOVES INTO THE FORECAST AREA. SNOW SHOWERS ALREADY
DEVELOPING OVER SOUTHEAST WYOMING AND WILL QUICKLY SPREAD INTO THE
PANHANDLE THIS EVENING. MAINLY LOOKING FOR SCATTERED SNOW SHOWERS
TONIGHT WITH VERY LITTLE IN THE WAY OF SNOW ACCUMULATION. COULD
SEE AN INCH OR SO OF SNOW IN A FEW LOCATIONS BUT WILL BE ABOUT IT.
SNOW WILL MOSTLY END BY SUNRISE SUNDAY AS THE DISTURBANCE QUICKLY
MOVES SOUTHEAST INTO THE PLAINS.


&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 514 PM MST SAT JAN 31 2015

TWO UPPER LEVEL DISTURBANCES AFFECTING THE AREA THIS EVENING. THE
FIRST UPPER DISTURBANCE IS NO EXITING THE NEBRASKA PANHANDLE. SNOW
WILL QUICKLY END EARLY THIS EVENING AS THIS DISTURBANCE EXITS BUT
THE NEXT NORTHERN STREAM DISTURBANCE WILL QUICKLY MOVE FROM NORTH
CENTRAL WYOMING EARLY THIS EVENING INTO SOUTHEAST WYOMING BY LATE
THIS EVENING. SNOW SHOWERS WILL DEVELOP ACROSS SOUTHEAST WYOMING
AND NEBRASKA PANHANDLE THIS EVENING WITH SNOW SHOWERS ENDING LATE
TONIGHT AS THE DISTURBANCE RAPIDLY MOVES THROUGH THE AREA. IFR TO
MVFR IS EXPECTED TONIGHT DUE TO LOW CLOUDS AND SNOW SHOWERS.
MOUNTAIN TOPS WILL BE OBSCURED AND MOUNTAINS MAY BE OBSCURED AT
TIMES.


&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH



000
FXUS65 KCYS 010021
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
521 PM MST SAT JAN 31 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 514 PM MST SAT JAN 31 2015

TWO UPPER LEVEL DISTURBANCES AFFECTING THE AREA THIS EVENING. THE
FIRST UPPER DISTURBANCE IS NO EXITING THE NEBRASKA PANHANDLE. SNOW
WILL QUICKLY END EARLY THIS EVENING AS THIS DISTURBANCE EXITS BUT
THE NEXT NORTHERN STREAM DISTURBANCE WILL QUICKLY MOVE FROM NORTH
CENTRAL WYOMING EARLY THIS EVENING INTO SOUTHEAST WYOMING BY LATE
THIS EVENING. SNOW SHOWERS WILL DEVELOP ACROSS SOUTHEAST WYOMING
AND NEBRASKA PANHANDLE THIS EVENING WITH SNOW SHOWERS ENDING LATE
TONIGHT AS THE DISTURBANCE RAPIDLY MOVES THROUGH THE AREA. IFR TO
MVFR IS EXPECTED TONIGHT DUE TO LOW CLOUDS AND SNOW SHOWERS.
MOUNTAIN TOPS WILL BE OBSCURED AND MOUNTAINS MAY BE OBSCURED AT
TIMES.

&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH



000
FXUS65 KCYS 010021
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
521 PM MST SAT JAN 31 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 514 PM MST SAT JAN 31 2015

TWO UPPER LEVEL DISTURBANCES AFFECTING THE AREA THIS EVENING. THE
FIRST UPPER DISTURBANCE IS NO EXITING THE NEBRASKA PANHANDLE. SNOW
WILL QUICKLY END EARLY THIS EVENING AS THIS DISTURBANCE EXITS BUT
THE NEXT NORTHERN STREAM DISTURBANCE WILL QUICKLY MOVE FROM NORTH
CENTRAL WYOMING EARLY THIS EVENING INTO SOUTHEAST WYOMING BY LATE
THIS EVENING. SNOW SHOWERS WILL DEVELOP ACROSS SOUTHEAST WYOMING
AND NEBRASKA PANHANDLE THIS EVENING WITH SNOW SHOWERS ENDING LATE
TONIGHT AS THE DISTURBANCE RAPIDLY MOVES THROUGH THE AREA. IFR TO
MVFR IS EXPECTED TONIGHT DUE TO LOW CLOUDS AND SNOW SHOWERS.
MOUNTAIN TOPS WILL BE OBSCURED AND MOUNTAINS MAY BE OBSCURED AT
TIMES.

&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH




000
FXUS65 KCYS 010021
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
521 PM MST SAT JAN 31 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 514 PM MST SAT JAN 31 2015

TWO UPPER LEVEL DISTURBANCES AFFECTING THE AREA THIS EVENING. THE
FIRST UPPER DISTURBANCE IS NO EXITING THE NEBRASKA PANHANDLE. SNOW
WILL QUICKLY END EARLY THIS EVENING AS THIS DISTURBANCE EXITS BUT
THE NEXT NORTHERN STREAM DISTURBANCE WILL QUICKLY MOVE FROM NORTH
CENTRAL WYOMING EARLY THIS EVENING INTO SOUTHEAST WYOMING BY LATE
THIS EVENING. SNOW SHOWERS WILL DEVELOP ACROSS SOUTHEAST WYOMING
AND NEBRASKA PANHANDLE THIS EVENING WITH SNOW SHOWERS ENDING LATE
TONIGHT AS THE DISTURBANCE RAPIDLY MOVES THROUGH THE AREA. IFR TO
MVFR IS EXPECTED TONIGHT DUE TO LOW CLOUDS AND SNOW SHOWERS.
MOUNTAIN TOPS WILL BE OBSCURED AND MOUNTAINS MAY BE OBSCURED AT
TIMES.

&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH



000
FXUS65 KCYS 010021
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
521 PM MST SAT JAN 31 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADIENTS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADIAN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN
MOVING INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS
TUESDAY NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF
THE CWA BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN
AND WEAK IMPULSE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF
THE CWA LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS
BY LATE WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF
THE MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS
RIDGING TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE
SLOWLY DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 514 PM MST SAT JAN 31 2015

TWO UPPER LEVEL DISTURBANCES AFFECTING THE AREA THIS EVENING. THE
FIRST UPPER DISTURBANCE IS NO EXITING THE NEBRASKA PANHANDLE. SNOW
WILL QUICKLY END EARLY THIS EVENING AS THIS DISTURBANCE EXITS BUT
THE NEXT NORTHERN STREAM DISTURBANCE WILL QUICKLY MOVE FROM NORTH
CENTRAL WYOMING EARLY THIS EVENING INTO SOUTHEAST WYOMING BY LATE
THIS EVENING. SNOW SHOWERS WILL DEVELOP ACROSS SOUTHEAST WYOMING
AND NEBRASKA PANHANDLE THIS EVENING WITH SNOW SHOWERS ENDING LATE
TONIGHT AS THE DISTURBANCE RAPIDLY MOVES THROUGH THE AREA. IFR TO
MVFR IS EXPECTED TONIGHT DUE TO LOW CLOUDS AND SNOW SHOWERS.
MOUNTAIN TOPS WILL BE OBSCURED AND MOUNTAINS MAY BE OBSCURED AT
TIMES.

&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...CAH
LONG TERM...RE
AVIATION...SML
FIRE WEATHER...CAH




000
FXUS63 KUNR 312335
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
435 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 426 PM MST SAT JAN 31 2015

LOSS OF SOLAR INSOLATION ABOVE ST/FG DECK IS ALLOWING FZDZ TO
ACCUMULATE ON ROADS IN/NEAR THE BLACK HILLS...WHERE BEST UPSLOPE
ENHANCED FREEZING DRIZZLE/FOG ARE OCCURRING. HAVE HOISTED AN
ADVISORY TO ACCOUNT.

ACTIVITY SHOULD QUICKLY TURN TO SNOW AS TROUGH CURRENTLY ACROSS
SOUTHWEST ND INTO CENTRAL WY SWEEPS ACROSS THE CWA EARLY THIS
EVENING.

&&

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 148 PM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS. PHASING
NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL SUPPORT
CYCLOGENESIS ACROSS THE CENTRAL PLAINS...WITH A DEVELOPING
DEFORMATION ZONE NW OF THE LOW. THE FA WILL SEE INFLUENCE FROM
BOTH OF THESE SYSTEMS WITH THE NORTHERN COUNTERPART AFFECTING MOST
OF THE FA...WHILE SCENTRAL SD WILL SEE AN INFLUENCE FROM BOTH.
BACKDOOR COLD FRONT HAS SPREAD SW ACROSS THE FA...WITH FG AND
AREAS OF ZL IN ITS WAKE. EXPECTING FG AND ZL TO TAPPER OFF LATE
THIS AFTERNOON AND EARLY EVENING AS THERMAL PROFILES COOL AND ICE
NUCLEATION ENSUES. IN ADDITION...SEEDER FEEDER FROM DEVELOPING
SNOWS WILL ALSO SCOUR AVAILABLE NUCLEI. MAIN STORY WILL BE SNOWS
TONIGHT. STRONG UPPER JET STREAK ASSOCIATED WITH THE NORTHERN
STREAM SHORTWAVE WILL COMBINE WITH AN ASSOCIATED ARCTIC FRONT TO
SUPPORT SNOWS ACROSS MOST OF EH FA TONIGHT...SPREADING QUICKLY SE
FROM NW SD THIS EVENING. MUCH OF WESTERN SD AND PORTIONS OF NE WY
WILL SEE AROUND AN INCH TO 2 INCHES OF SNOW...POSSIBLY NEAR 3 IN
THE FAR NE NEAR LEMMON. THE NORTHERN BLACK HILLS AND FOOTHILLS
WILL ALSO SEE SOME UPSLOPE ENHANCEMENT...WITH CLOSER TO 3 INCHES
POSSIBLE THERE. MOST OF THE SNOW WILL FALL THIS EVENING...WITH
RESIDUAL LIGHT SNOW THE REMAINDER OF THE NIGHT.

A LITTLE DIFFERENT PROCESS EXPECTED OVER SCENTRAL SD. MASSIVE SW
CONUS UPPER LOW WILL EJECT INTO THE CENTRAL PLAINS AND CONTINUE TO
SUPPORT VIGOROUS CYCLOGENESIS IN THE EASTERN CENTRAL PLAINS AND
MIDWEST. MOIST CONVEYOR BELT ASSOCIATED WITH THIS PROCESS WILL
SUPPORT A STRENGTHENING DEFORMATION ZONE ACROSS CENTRAL NE INTO
SCENTRAL SD TONIGHT...WHERE LOCALLY ENHANCED SNOW RATES CAN BE
EXPECTED. IN ADDITION...PHASING NORTHERN STREAM IMPULSE WILL SUPPORT
A BRIEF STALL/PIVOT OF THE MOISTURE CONVEYOR BELT AND ASSOCIATED
DEFORMATION ZONE/FGEN...SUPPORTING A 2-4 HOUR EXTENSION OF DECENT
SNOWFALL. BOTTOM LINE EXPECTING 2-5 INCHES ACROSS MELLETTE...TODD
AND ESP TRIPP COUNTIES. LOCALLY HIGHER AMOUNTS COULD BE POSSIBLE IF
THE ENTIRE PROCESS SHIFTS A BIT FARTHER NW AND PAUSES LONGER. SNOW
WILL WIND DOWN QUICKLY SUNDAY MORNING WITH CLEARING SUNDAY AFTERNOON
MOST IF NOT ALL PLACES. A BRIEF SKIRT OF ARCTIC AIR WILL SUPPORT
MUCH COLDER TEMPERATURES ACROSS THE FA THROUGH SUNDAY. ACTIVE NW FLOW
WILL PERSIST WITH A LL BAROCLINIC ZONE REMAINING ACROSS THE FA. THE
NEXT IN A SERIES OF IMPULSES WILL ARRIVE LATE SUNDAY NIGHT...AND MAY
SUPPORT SNOW TOWARD DAWN MONDAY ACROSS THE FAR NW.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD. A RELATIVELY WEAK SHORTWAVE WILL BRING A
CHANCE OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY.
A BETTER DEFINED UPPER TROUGH/JET STREAK WILL AFFECT THE AREA ON
TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH AT THE
SURFACE...BRINGING A CHANCE OF SNOW TO THE AREA. AT THIS TIME IT
LOOKS LIKE THE BEST AREA FOR MEASURABLE SNOW ACCUMULATION WOULD BE
OVER PARTS OF NORTHEASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA.
SNOW MAY LINGER INTO WEDNESDAY ACROSS THE SOUTHWESTERN CWA...BUT
DRY WEATHER IS THEN EXPECTED THROUGH THE REST OF THE WEEK AS A
RIDGE BUILDS OVER THE WESTERN CONUS.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...ESPECIALLY ACROSS THE SOUTHWEST HALF OF THE
CWA. BELOW NORMAL TEMPS ARE EXPECTED ON WEDNESDAY AS THE BOUNDARY
SHIFTS SOUTH. WESTERLY WINDS WILL AID IN SIGNIFICANT WARMING FOR THE
END OF THE WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 426 PM MST SAT JAN 31 2015

WIDESPREAD IFR CONDITIONS DUE TO -SN/FG/FZDZ WILL CONTINUE THIS
EVENING ACROSS THE ENTIRE AREA. AREAS LIFR CONDITIONS EXPECTED
WITH THICKEST FOG/TERRAIN INTERACTION. CONDITIONS WILL QUICKLY
IMPROVE FROM NORTHWEST TO SOUTHEAST OVERNIGHT AND ESPECIALLY SUNDAY.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR SDZ046-047-049.

     FREEZING RAIN ADVISORY UNTIL 9 PM MST THIS EVENING FOR SDZ012-
     025-026-030-031-072>074.

WY...NONE.
&&

$$

UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...HELGESON




000
FXUS63 KUNR 312335
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
435 PM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 426 PM MST SAT JAN 31 2015

LOSS OF SOLAR INSOLATION ABOVE ST/FG DECK IS ALLOWING FZDZ TO
ACCUMULATE ON ROADS IN/NEAR THE BLACK HILLS...WHERE BEST UPSLOPE
ENHANCED FREEZING DRIZZLE/FOG ARE OCCURRING. HAVE HOISTED AN
ADVISORY TO ACCOUNT.

ACTIVITY SHOULD QUICKLY TURN TO SNOW AS TROUGH CURRENTLY ACROSS
SOUTHWEST ND INTO CENTRAL WY SWEEPS ACROSS THE CWA EARLY THIS
EVENING.

&&

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 148 PM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS. PHASING
NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL SUPPORT
CYCLOGENESIS ACROSS THE CENTRAL PLAINS...WITH A DEVELOPING
DEFORMATION ZONE NW OF THE LOW. THE FA WILL SEE INFLUENCE FROM
BOTH OF THESE SYSTEMS WITH THE NORTHERN COUNTERPART AFFECTING MOST
OF THE FA...WHILE SCENTRAL SD WILL SEE AN INFLUENCE FROM BOTH.
BACKDOOR COLD FRONT HAS SPREAD SW ACROSS THE FA...WITH FG AND
AREAS OF ZL IN ITS WAKE. EXPECTING FG AND ZL TO TAPPER OFF LATE
THIS AFTERNOON AND EARLY EVENING AS THERMAL PROFILES COOL AND ICE
NUCLEATION ENSUES. IN ADDITION...SEEDER FEEDER FROM DEVELOPING
SNOWS WILL ALSO SCOUR AVAILABLE NUCLEI. MAIN STORY WILL BE SNOWS
TONIGHT. STRONG UPPER JET STREAK ASSOCIATED WITH THE NORTHERN
STREAM SHORTWAVE WILL COMBINE WITH AN ASSOCIATED ARCTIC FRONT TO
SUPPORT SNOWS ACROSS MOST OF EH FA TONIGHT...SPREADING QUICKLY SE
FROM NW SD THIS EVENING. MUCH OF WESTERN SD AND PORTIONS OF NE WY
WILL SEE AROUND AN INCH TO 2 INCHES OF SNOW...POSSIBLY NEAR 3 IN
THE FAR NE NEAR LEMMON. THE NORTHERN BLACK HILLS AND FOOTHILLS
WILL ALSO SEE SOME UPSLOPE ENHANCEMENT...WITH CLOSER TO 3 INCHES
POSSIBLE THERE. MOST OF THE SNOW WILL FALL THIS EVENING...WITH
RESIDUAL LIGHT SNOW THE REMAINDER OF THE NIGHT.

A LITTLE DIFFERENT PROCESS EXPECTED OVER SCENTRAL SD. MASSIVE SW
CONUS UPPER LOW WILL EJECT INTO THE CENTRAL PLAINS AND CONTINUE TO
SUPPORT VIGOROUS CYCLOGENESIS IN THE EASTERN CENTRAL PLAINS AND
MIDWEST. MOIST CONVEYOR BELT ASSOCIATED WITH THIS PROCESS WILL
SUPPORT A STRENGTHENING DEFORMATION ZONE ACROSS CENTRAL NE INTO
SCENTRAL SD TONIGHT...WHERE LOCALLY ENHANCED SNOW RATES CAN BE
EXPECTED. IN ADDITION...PHASING NORTHERN STREAM IMPULSE WILL SUPPORT
A BRIEF STALL/PIVOT OF THE MOISTURE CONVEYOR BELT AND ASSOCIATED
DEFORMATION ZONE/FGEN...SUPPORTING A 2-4 HOUR EXTENSION OF DECENT
SNOWFALL. BOTTOM LINE EXPECTING 2-5 INCHES ACROSS MELLETTE...TODD
AND ESP TRIPP COUNTIES. LOCALLY HIGHER AMOUNTS COULD BE POSSIBLE IF
THE ENTIRE PROCESS SHIFTS A BIT FARTHER NW AND PAUSES LONGER. SNOW
WILL WIND DOWN QUICKLY SUNDAY MORNING WITH CLEARING SUNDAY AFTERNOON
MOST IF NOT ALL PLACES. A BRIEF SKIRT OF ARCTIC AIR WILL SUPPORT
MUCH COLDER TEMPERATURES ACROSS THE FA THROUGH SUNDAY. ACTIVE NW FLOW
WILL PERSIST WITH A LL BAROCLINIC ZONE REMAINING ACROSS THE FA. THE
NEXT IN A SERIES OF IMPULSES WILL ARRIVE LATE SUNDAY NIGHT...AND MAY
SUPPORT SNOW TOWARD DAWN MONDAY ACROSS THE FAR NW.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD. A RELATIVELY WEAK SHORTWAVE WILL BRING A
CHANCE OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY.
A BETTER DEFINED UPPER TROUGH/JET STREAK WILL AFFECT THE AREA ON
TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH AT THE
SURFACE...BRINGING A CHANCE OF SNOW TO THE AREA. AT THIS TIME IT
LOOKS LIKE THE BEST AREA FOR MEASURABLE SNOW ACCUMULATION WOULD BE
OVER PARTS OF NORTHEASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA.
SNOW MAY LINGER INTO WEDNESDAY ACROSS THE SOUTHWESTERN CWA...BUT
DRY WEATHER IS THEN EXPECTED THROUGH THE REST OF THE WEEK AS A
RIDGE BUILDS OVER THE WESTERN CONUS.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...ESPECIALLY ACROSS THE SOUTHWEST HALF OF THE
CWA. BELOW NORMAL TEMPS ARE EXPECTED ON WEDNESDAY AS THE BOUNDARY
SHIFTS SOUTH. WESTERLY WINDS WILL AID IN SIGNIFICANT WARMING FOR THE
END OF THE WEEK.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 426 PM MST SAT JAN 31 2015

WIDESPREAD IFR CONDITIONS DUE TO -SN/FG/FZDZ WILL CONTINUE THIS
EVENING ACROSS THE ENTIRE AREA. AREAS LIFR CONDITIONS EXPECTED
WITH THICKEST FOG/TERRAIN INTERACTION. CONDITIONS WILL QUICKLY
IMPROVE FROM NORTHWEST TO SOUTHEAST OVERNIGHT AND ESPECIALLY SUNDAY.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR SDZ046-047-049.

     FREEZING RAIN ADVISORY UNTIL 9 PM MST THIS EVENING FOR SDZ012-
     025-026-030-031-072>074.

WY...NONE.
&&

$$

UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...HELGESON





000
FXUS65 KRIW 312330 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
242 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXCEPT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

CLOUDS WILL LOWER OVER NORTHERN WY WITH AREAS OF LIGHT SNOW
DEVELOPING AROUND 00Z THROUGH 09Z BEFORE IT ENDS AND CONDITIONS
IMPROVE BY 12Z. EXPECT MVFR TO IFR CONDITIONS THROUGH 15Z WITH VFR
CONDITIONS AFTER 15Z SUNDAY. FOR THE CENTRAL AREA FROM KCPR TO
KLND THE LOWER CLOUDS AND AREAS OF LIGHT SNOW WILL OCCUR AROUND
03Z AND CONTINUE THROUGH 12Z. EXPECT MVFR TO IFR CONDITIONS
THROUGH 15Z...THEN CONDITIONS WILL IMPROVE AFTER 15Z WITH VFR
CONDITIONS PREVAILING BY 18Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

SOME FOG AND LOW CLOUDS WILL OCCUR IN THE STAR VALLEY TONIGHT INTO
SUNDAY MORNING WITH IFR CONDITIONS UNTIL 17Z. A COLD FRONT MAY PUSH
LOWER MVFR/IFR CIGS INTO VCNTY KRKS AFTER 07Z TONIGHT. ISOLATED
SNOW SHOWERS ARE EXPECTED OVER THE NORTHWEST MOUNTAINS AND OVER
THE WIND RIVER MOUNTAINS TONIGHT UNTIL 12Z SUNDAY. LOCAL MVFR
CONDITIONS WILL OCCUR IN THESE MOUNTAINS. VFR CONDITIONS WILL
PREVAIL SUNDAY AT THE TERMINAL SITES. SOME LIGHT SNOW FORMS OVER
THE NORTHWEST MOUNTAINS AFTER 20Z SUNDAY WITH SOME MVFR CONDITIONS
DEVELOPING BY 00Z MONDAY IN NW WY.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AR
FIRE WEATHER...AR








000
FXUS65 KRIW 312330 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
242 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXCEPT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

CLOUDS WILL LOWER OVER NORTHERN WY WITH AREAS OF LIGHT SNOW
DEVELOPING AROUND 00Z THROUGH 09Z BEFORE IT ENDS AND CONDITIONS
IMPROVE BY 12Z. EXPECT MVFR TO IFR CONDITIONS THROUGH 15Z WITH VFR
CONDITIONS AFTER 15Z SUNDAY. FOR THE CENTRAL AREA FROM KCPR TO
KLND THE LOWER CLOUDS AND AREAS OF LIGHT SNOW WILL OCCUR AROUND
03Z AND CONTINUE THROUGH 12Z. EXPECT MVFR TO IFR CONDITIONS
THROUGH 15Z...THEN CONDITIONS WILL IMPROVE AFTER 15Z WITH VFR
CONDITIONS PREVAILING BY 18Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

SOME FOG AND LOW CLOUDS WILL OCCUR IN THE STAR VALLEY TONIGHT INTO
SUNDAY MORNING WITH IFR CONDITIONS UNTIL 17Z. A COLD FRONT MAY PUSH
LOWER MVFR/IFR CIGS INTO VCNTY KRKS AFTER 07Z TONIGHT. ISOLATED
SNOW SHOWERS ARE EXPECTED OVER THE NORTHWEST MOUNTAINS AND OVER
THE WIND RIVER MOUNTAINS TONIGHT UNTIL 12Z SUNDAY. LOCAL MVFR
CONDITIONS WILL OCCUR IN THESE MOUNTAINS. VFR CONDITIONS WILL
PREVAIL SUNDAY AT THE TERMINAL SITES. SOME LIGHT SNOW FORMS OVER
THE NORTHWEST MOUNTAINS AFTER 20Z SUNDAY WITH SOME MVFR CONDITIONS
DEVELOPING BY 00Z MONDAY IN NW WY.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AR
FIRE WEATHER...AR








000
FXUS65 KRIW 312330 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
242 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXCEPT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

CLOUDS WILL LOWER OVER NORTHERN WY WITH AREAS OF LIGHT SNOW
DEVELOPING AROUND 00Z THROUGH 09Z BEFORE IT ENDS AND CONDITIONS
IMPROVE BY 12Z. EXPECT MVFR TO IFR CONDITIONS THROUGH 15Z WITH VFR
CONDITIONS AFTER 15Z SUNDAY. FOR THE CENTRAL AREA FROM KCPR TO
KLND THE LOWER CLOUDS AND AREAS OF LIGHT SNOW WILL OCCUR AROUND
03Z AND CONTINUE THROUGH 12Z. EXPECT MVFR TO IFR CONDITIONS
THROUGH 15Z...THEN CONDITIONS WILL IMPROVE AFTER 15Z WITH VFR
CONDITIONS PREVAILING BY 18Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

SOME FOG AND LOW CLOUDS WILL OCCUR IN THE STAR VALLEY TONIGHT INTO
SUNDAY MORNING WITH IFR CONDITIONS UNTIL 17Z. A COLD FRONT MAY PUSH
LOWER MVFR/IFR CIGS INTO VCNTY KRKS AFTER 07Z TONIGHT. ISOLATED
SNOW SHOWERS ARE EXPECTED OVER THE NORTHWEST MOUNTAINS AND OVER
THE WIND RIVER MOUNTAINS TONIGHT UNTIL 12Z SUNDAY. LOCAL MVFR
CONDITIONS WILL OCCUR IN THESE MOUNTAINS. VFR CONDITIONS WILL
PREVAIL SUNDAY AT THE TERMINAL SITES. SOME LIGHT SNOW FORMS OVER
THE NORTHWEST MOUNTAINS AFTER 20Z SUNDAY WITH SOME MVFR CONDITIONS
DEVELOPING BY 00Z MONDAY IN NW WY.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AR
FIRE WEATHER...AR








000
FXUS65 KRIW 312330 CCA
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
242 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXCEPT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

CLOUDS WILL LOWER OVER NORTHERN WY WITH AREAS OF LIGHT SNOW
DEVELOPING AROUND 00Z THROUGH 09Z BEFORE IT ENDS AND CONDITIONS
IMPROVE BY 12Z. EXPECT MVFR TO IFR CONDITIONS THROUGH 15Z WITH VFR
CONDITIONS AFTER 15Z SUNDAY. FOR THE CENTRAL AREA FROM KCPR TO
KLND THE LOWER CLOUDS AND AREAS OF LIGHT SNOW WILL OCCUR AROUND
03Z AND CONTINUE THROUGH 12Z. EXPECT MVFR TO IFR CONDITIONS
THROUGH 15Z...THEN CONDITIONS WILL IMPROVE AFTER 15Z WITH VFR
CONDITIONS PREVAILING BY 18Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

SOME FOG AND LOW CLOUDS WILL OCCUR IN THE STAR VALLEY TONIGHT INTO
SUNDAY MORNING WITH IFR CONDITIONS UNTIL 17Z. A COLD FRONT MAY PUSH
LOWER MVFR/IFR CIGS INTO VCNTY KRKS AFTER 07Z TONIGHT. ISOLATED
SNOW SHOWERS ARE EXPECTED OVER THE NORTHWEST MOUNTAINS AND OVER
THE WIND RIVER MOUNTAINS TONIGHT UNTIL 12Z SUNDAY. LOCAL MVFR
CONDITIONS WILL OCCUR IN THESE MOUNTAINS. VFR CONDITIONS WILL
PREVAIL SUNDAY AT THE TERMINAL SITES. SOME LIGHT SNOW FORMS OVER
THE NORTHWEST MOUNTAINS AFTER 20Z SUNDAY WITH SOME MVFR CONDITIONS
DEVELOPING BY 00Z MONDAY IN NW WY.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AR
FIRE WEATHER...AR








000
FXUS65 KCYS 312226
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
326 PM MST SAT JAN 31 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADEITNS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADAIN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN MOVING
INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS TUESDAY
NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF THE CWA
BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN AND WEAK
IMPULESE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF THE CWA
LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS BY LATE
WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF THE
MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS RIDGING
TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE SLOWLY
DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 324 PM MST SAT JAN 31 2015

FAIRLY WIDESPREAD MVFR/IFR CONDITIONS DUE TO LOW CIGS EXPECTED TO
RETURN TO THE AREA TONIGHT WITH AREAS OF LIGHT SNOW AS WELL.
CONDITIONS EXPECTED TO IMPROVE SUNDAY MORNING WITH MAINLY VFR BY
MONDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...CAH
LONG TERM...RE
AVIATION...RE
FIRE WEATHER...CAH



000
FXUS65 KCYS 312226
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
326 PM MST SAT JAN 31 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 324 PM MST SAT JAN 31 2015

DISORGANIZED SPLIT FLOW PATTERN UNDERWAY ACROSS THE INTERMOUNTAIN
WEST AS UPPER-LOW CUTS OFF NR THE BAJA OF CALIFORNIA. TWO SHORTWAVES
EMBEDDED WITHIN NRN STREAM NORTHWEST FLOW HAVE BEEN THE DOMINANT
FEATURES TODAY AND WILL BE AGAIN TONIGHT. FIRST SHORTWAVE TROF THAT
WAS AT LEAST IN PART THE REASON FOR -SN LAST NT AND EARLIER TODAY
WAS SLOWLY DEPARTING THIS AFTERNOON. WELL DEFINED TROF AXIS EVIDENT
ON SATELLITE IMAGERY BY SHARP BACK EDGE OF CLOUD COVER THAT AT 20Z
EXTENDED FROM AROUND LUSK TO LARAMIE/CHEYENNE. POCKETS OF -SN WERE
STILL FALLING AHEAD OF THIS FTR OVR THE CENTRAL AND SRN NEBRASKA
PANHANDLE. MOST AREAS HAD RECEIVED AROUND AN INCH OF NEW SNOW TODAY
WITH LOCALLY UP TO A COUPLE OF INCHES IN THE WILDCAT HILLS AND NR
ALLIANCE. WILL SEE A GRADUALLY DECREASE W-E IN BOTH COVERAGE AND
INTENSITY AS THE TROF AXIS MARCHES EAST THRU THE REST OF THE
AFTERNOON. PERHAPS UP TO ANOTHER INCH WILL FALL IN THESE AREAS
THIS AFTERNOON. THE 2ND SHORTWAVE TROF QUICK ON THE HEELS OF THE
DEPARTING 1ST ONE...WILL DIVE SOUTHEAST TONIGHT AND COMBINE WITH
DEEPENING OF THE COLDER AIR MASS TO BOOST SNOW CHANCES AGAIN
TONIGHT. MOST AREAS WILL SEE AN ADDITIONAL SHOT OF LIGHT SNOW
TONIGHT AS A RESULT...WITH PERHAPS LOCALLY ANOTHER INCH OR TWO
TONIGHT. SNOWFALL RATES WILL JUST NOT BE HIGH ENOUGH TO PRODUCE
MUCH OF AN IMPACT...THOUGH SOME SLICK ROADS WILL BE A POSSIBILITY
LATER TONIGHT. THIS 2ND SHORTWAVE WILL DEPART INTO THE PLAINS
QUICKLY SUNDAY BRINGING AN END TO SNOW CHANCES EARLY. CLOUDS WILL
DECREASE ON SUNDAY ALLOWING MORE SUNSHINE THAN RECENT DAYS. MORE
SUN WILL DO LITTLE TO HELP TEMPS RECOVER HOWEVER AS THE COLDER
AIR MASS HOLDS HIGH TEMPERATURES IN THE 20S TO MAYBE AROUND 30F.

FOCUS SHIFTS TO HIGH WIND POTENTIAL FOR SUNDAY NT AND AGAIN ON
MONDAY NT AS A SERIES OF SHORTWAVES TRAVERSE THE NORTHWEST FLOW. THE
SUNDAY NT EVENT LOOKS FAIRLY MARGINAL AT THIS POINT...AS LLVL KCAG-
KCPR HEIGHTS INCREASE TO AROUND 55 METERS. IN FACT...12Z MODEL DATA
HAS BACKED OFF SOMEWHAT ON LLVL GRADEITNS COMPARED TO THE 00Z
RUN. THE BIGGER EVENT LOOKS TO BE MONDAY NT WHERE LLVL KCAG-KCPR
GRADIENTS CLIMB TO AROUND 70 METERS AT THE SAME TIME THAT THE NOSE
OF AN ANTICYCLONIC 115 KNOT H3 JET STREAK MOVES IN. FOR NOW WILL
HOLD OFF ON A WIND HIGHLIGHT AND WILL LET NEXT SHIFT GIVE 00Z DATA
ANOTHER LOOK. CONFIDENCE IS GREATEST ON THE MONDAY NT EVENT.
OTHERWISE...THE SNOWY/SIERRA MADRE RANGE CAN EXPECT FAIRLY
PERSISTENT LIGHT SNOW AS FAVORABLE OROGRAPHIC FLOW COMBINES WITH
PERIODIC BOUTS OF MID-LEVEL MOISTURE ASSOCIATED WITH THE SERIES OF
SHORTWAVES. DRY...BREEZY AND WARMER CONDITIONS WILL RETURN FOR
LOWER ELEVATIONS MONDAY WITH HIGHS RISING INTO THE 40S TO NR 50
EAST.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 324 PM MST SAT JAN 31 2015

MODELS IN GENERAL AGREEMENT WITH THE OVERALL PATTERN FEATURING A
GENERALLY WNW FLOW ALOFT THIS PERIOD. A MINOR SHORTWAVE WILL PASS
ACROSS TUESDAY BRINGING A FEW SNOW SHOWERS TO MAINLY THE MTNS WITH
OTHERWISE MILD TEMPS THAT DAY. IN THE MEANTIME A PUSH OF COLDER
CANADAIN AIR WILL SINK SOUTH OUT OF CANADA AND SHOULD BEGIN MOVING
INTO THE CWA LATE TUESDAY...BACKING UP AGAINST THE MTNS TUESDAY
NIGHT AND WEDS. CORE OF THIS COLD AIR WILL PASS EAST OF THE CWA
BUT STILL A GLANCING SHOT. FAVORABLE OVERRUNNING PATTERN AND WEAK
IMPULESE SHOULD ALLOW FOR SOME LIGHT SNOW ACROSS MUCH OF THE CWA
LATER TUESDAY NIGHT INTO WEDS BEFORE THE UPSLOPE FLOW ENDS BY LATE
WEDS. UNDERCUT GUIDANCE TEMPS FOR WEDS ESPECIALLY EAST OF THE
MTNS. THURSDAY AND FRIDAY LOOKING WARMER AND MAINLY DRY AS RIDGING
TO THE WEST SHIFTS SLOWLY EAST TOWARDS THE AREA WHILE SLOWLY
DEAMPLIFYING. A MORE ZONAL FLOW SETTING UP FOR NEXT WEEKEND
KEEPING MILD TEMPS IN PLACE BUT SHOULD SEE AN UPTICK IN WIND.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 324 PM MST SAT JAN 31 2015

FAIRLY WIDESPREAD MVFR/IFR CONDITIONS DUE TO LOW CIGS EXPECTED TO
RETURN TO THE AREA TONIGHT WITH AREAS OF LIGHT SNOW AS WELL.
CONDITIONS EXPECTED TO IMPROVE SUNDAY MORNING WITH MAINLY VFR BY
MONDAY AFTERNOON.

&&

.FIRE WEATHER...
ISSUED AT 324 PM MST SAT JAN 31 2015

NO FIRE WEATHER CONCERNS INTO EARLY NEXT WEEK.
AFTER A COOLER DAY ON SUNDAY...HIGH TEMPERATURES WILL RETURN TO THE
40S AND 50S FOR MONDAY AND TUESDAY. MOUNTAIN SNOW ALONG WITH BREEZY
TO LOCALLY WINDY CONDITIONS WILL RETURN EARLY NEXT WEEK AS WELL.
MINIMUM RELATIVE HUMIDITIES WILL NOT DROP BELOW 30 PERCENT DURING
THIS PERIOD.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...CAH
LONG TERM...RE
AVIATION...RE
FIRE WEATHER...CAH




000
FXUS65 KRIW 312142
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
242 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXPECT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

CLOUDS WILL LOWER OVER NORTHERN WY WITH AREAS OF LIGHT SNOW
DEVELOPING AROUND 00Z THROUGH 09Z BEFORE IT ENDS AND CONDITIONS
IMPROVE BY 12Z. EXPECT MVFR TO IFR CONDITIONS THROUGH 15Z WITH VFR
CONDITIONS AFTER 15Z SUNDAY. FOR THE CENTRAL AREA FROM KCPR TO
KLND THE LOWER CLOUDS AND AREAS OF LIGHT SNOW WILL OCCUR AROUND
03Z AND CONTINUE THROUGH 12Z. EXPECT MVFR TO IFR CONDITIONS
THROUGH 15Z...THEN CONDITIONS WILL IMPROVE AFTER 15Z WITH VFR
CONDITIONS PREVAILING BY 18Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

SOME FOG AND LOW CLOUDS WILL OCCUR IN THE STAR VALLEY TONIGHT INTO
SUNDAY MORNING WITH IFR CONDITIONS UNTIL 17Z. A COLD FRONT MAY PUSH
LOWER MVFR/IFR CIGS INTO VCNTY KRKS AFTER 07Z TONIGHT. ISOLATED
SNOW SHOWERS ARE EXPECTED OVER THE NORTHWEST MOUNTAINS AND OVER
THE WIND RIVER MOUNTAINS TONIGHT UNTIL 12Z SUNDAY. LOCAL MVFR
CONDITIONS WILL OCCUR IN THESE MOUNTAINS. VFR CONDITIONS WILL
PREVAIL SUNDAY AT THE TERMINAL SITES. SOME LIGHT SNOW FORMS OVER
THE NORTHWEST MOUNTAINS AFTER 20Z SUNDAY WITH SOME MVFR CONDITIONS
DEVELOPING BY 00Z MONDAY IN NW WY.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AR
FIRE WEATHER...AR






000
FXUS65 KRIW 312142
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
242 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXPECT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

CLOUDS WILL LOWER OVER NORTHERN WY WITH AREAS OF LIGHT SNOW
DEVELOPING AROUND 00Z THROUGH 09Z BEFORE IT ENDS AND CONDITIONS
IMPROVE BY 12Z. EXPECT MVFR TO IFR CONDITIONS THROUGH 15Z WITH VFR
CONDITIONS AFTER 15Z SUNDAY. FOR THE CENTRAL AREA FROM KCPR TO
KLND THE LOWER CLOUDS AND AREAS OF LIGHT SNOW WILL OCCUR AROUND
03Z AND CONTINUE THROUGH 12Z. EXPECT MVFR TO IFR CONDITIONS
THROUGH 15Z...THEN CONDITIONS WILL IMPROVE AFTER 15Z WITH VFR
CONDITIONS PREVAILING BY 18Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

SOME FOG AND LOW CLOUDS WILL OCCUR IN THE STAR VALLEY TONIGHT INTO
SUNDAY MORNING WITH IFR CONDITIONS UNTIL 17Z. A COLD FRONT MAY PUSH
LOWER MVFR/IFR CIGS INTO VCNTY KRKS AFTER 07Z TONIGHT. ISOLATED
SNOW SHOWERS ARE EXPECTED OVER THE NORTHWEST MOUNTAINS AND OVER
THE WIND RIVER MOUNTAINS TONIGHT UNTIL 12Z SUNDAY. LOCAL MVFR
CONDITIONS WILL OCCUR IN THESE MOUNTAINS. VFR CONDITIONS WILL
PREVAIL SUNDAY AT THE TERMINAL SITES. SOME LIGHT SNOW FORMS OVER
THE NORTHWEST MOUNTAINS AFTER 20Z SUNDAY WITH SOME MVFR CONDITIONS
DEVELOPING BY 00Z MONDAY IN NW WY.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AR
FIRE WEATHER...AR





000
FXUS65 KRIW 312142
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
242 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXPECT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

CLOUDS WILL LOWER OVER NORTHERN WY WITH AREAS OF LIGHT SNOW
DEVELOPING AROUND 00Z THROUGH 09Z BEFORE IT ENDS AND CONDITIONS
IMPROVE BY 12Z. EXPECT MVFR TO IFR CONDITIONS THROUGH 15Z WITH VFR
CONDITIONS AFTER 15Z SUNDAY. FOR THE CENTRAL AREA FROM KCPR TO
KLND THE LOWER CLOUDS AND AREAS OF LIGHT SNOW WILL OCCUR AROUND
03Z AND CONTINUE THROUGH 12Z. EXPECT MVFR TO IFR CONDITIONS
THROUGH 15Z...THEN CONDITIONS WILL IMPROVE AFTER 15Z WITH VFR
CONDITIONS PREVAILING BY 18Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

SOME FOG AND LOW CLOUDS WILL OCCUR IN THE STAR VALLEY TONIGHT INTO
SUNDAY MORNING WITH IFR CONDITIONS UNTIL 17Z. A COLD FRONT MAY PUSH
LOWER MVFR/IFR CIGS INTO VCNTY KRKS AFTER 07Z TONIGHT. ISOLATED
SNOW SHOWERS ARE EXPECTED OVER THE NORTHWEST MOUNTAINS AND OVER
THE WIND RIVER MOUNTAINS TONIGHT UNTIL 12Z SUNDAY. LOCAL MVFR
CONDITIONS WILL OCCUR IN THESE MOUNTAINS. VFR CONDITIONS WILL
PREVAIL SUNDAY AT THE TERMINAL SITES. SOME LIGHT SNOW FORMS OVER
THE NORTHWEST MOUNTAINS AFTER 20Z SUNDAY WITH SOME MVFR CONDITIONS
DEVELOPING BY 00Z MONDAY IN NW WY.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AR
FIRE WEATHER...AR






000
FXUS65 KRIW 312142
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
242 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXPECT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

CLOUDS WILL LOWER OVER NORTHERN WY WITH AREAS OF LIGHT SNOW
DEVELOPING AROUND 00Z THROUGH 09Z BEFORE IT ENDS AND CONDITIONS
IMPROVE BY 12Z. EXPECT MVFR TO IFR CONDITIONS THROUGH 15Z WITH VFR
CONDITIONS AFTER 15Z SUNDAY. FOR THE CENTRAL AREA FROM KCPR TO
KLND THE LOWER CLOUDS AND AREAS OF LIGHT SNOW WILL OCCUR AROUND
03Z AND CONTINUE THROUGH 12Z. EXPECT MVFR TO IFR CONDITIONS
THROUGH 15Z...THEN CONDITIONS WILL IMPROVE AFTER 15Z WITH VFR
CONDITIONS PREVAILING BY 18Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

SOME FOG AND LOW CLOUDS WILL OCCUR IN THE STAR VALLEY TONIGHT INTO
SUNDAY MORNING WITH IFR CONDITIONS UNTIL 17Z. A COLD FRONT MAY PUSH
LOWER MVFR/IFR CIGS INTO VCNTY KRKS AFTER 07Z TONIGHT. ISOLATED
SNOW SHOWERS ARE EXPECTED OVER THE NORTHWEST MOUNTAINS AND OVER
THE WIND RIVER MOUNTAINS TONIGHT UNTIL 12Z SUNDAY. LOCAL MVFR
CONDITIONS WILL OCCUR IN THESE MOUNTAINS. VFR CONDITIONS WILL
PREVAIL SUNDAY AT THE TERMINAL SITES. SOME LIGHT SNOW FORMS OVER
THE NORTHWEST MOUNTAINS AFTER 20Z SUNDAY WITH SOME MVFR CONDITIONS
DEVELOPING BY 00Z MONDAY IN NW WY.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AR
FIRE WEATHER...AR






000
FXUS65 KRIW 312142
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
242 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXPECT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

CLOUDS WILL LOWER OVER NORTHERN WY WITH AREAS OF LIGHT SNOW
DEVELOPING AROUND 00Z THROUGH 09Z BEFORE IT ENDS AND CONDITIONS
IMPROVE BY 12Z. EXPECT MVFR TO IFR CONDITIONS THROUGH 15Z WITH VFR
CONDITIONS AFTER 15Z SUNDAY. FOR THE CENTRAL AREA FROM KCPR TO
KLND THE LOWER CLOUDS AND AREAS OF LIGHT SNOW WILL OCCUR AROUND
03Z AND CONTINUE THROUGH 12Z. EXPECT MVFR TO IFR CONDITIONS
THROUGH 15Z...THEN CONDITIONS WILL IMPROVE AFTER 15Z WITH VFR
CONDITIONS PREVAILING BY 18Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

SOME FOG AND LOW CLOUDS WILL OCCUR IN THE STAR VALLEY TONIGHT INTO
SUNDAY MORNING WITH IFR CONDITIONS UNTIL 17Z. A COLD FRONT MAY PUSH
LOWER MVFR/IFR CIGS INTO VCNTY KRKS AFTER 07Z TONIGHT. ISOLATED
SNOW SHOWERS ARE EXPECTED OVER THE NORTHWEST MOUNTAINS AND OVER
THE WIND RIVER MOUNTAINS TONIGHT UNTIL 12Z SUNDAY. LOCAL MVFR
CONDITIONS WILL OCCUR IN THESE MOUNTAINS. VFR CONDITIONS WILL
PREVAIL SUNDAY AT THE TERMINAL SITES. SOME LIGHT SNOW FORMS OVER
THE NORTHWEST MOUNTAINS AFTER 20Z SUNDAY WITH SOME MVFR CONDITIONS
DEVELOPING BY 00Z MONDAY IN NW WY.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AR
FIRE WEATHER...AR






000
FXUS65 KRIW 312142
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
242 PM MST SAT JAN 31 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

LOW CLOUDS AND FOG TOOK UNTIL EARLY AFTERNOON TO LIFT IN THE CENTRAL
VALLEYS AS WELL AS IN THE STAR VALLEY. OTHERWISE A MOSTLY SUNNY DAY
WITH MILD TEMPS FOR THE MOST PART. A COLD FRONT HAS ENTERED NORTHERN
WY AS OF 19Z. PRECIP IS BREAKING OUT IN SOUTHERN MONTANA AS A
WEATHER SYSTEM DIVES SOUTHEAST THROUGH MONTANA AND HEADS TOWARD WY
FOR THE TONIGHT PERIOD. THIS SYSTEM WILL MAINLY IMPACT THE AREAS
EAST OF THE CONTINENTAL DIVIDE TONIGHT INTO EARLY SUNDAY WITH SOME
SNOW AND WIND AND COLDER TEMPS. THE BEST CHANCE OF SNOW WILL BE FROM
THE BIGHORN MOUNTAINS SOUTH TO CASPER MOUNTAIN...INCLUDING BUFFALO
TO CASPER. HAVE WENT HIGHER WITH THE CHANCE OF SNOW WITH
ACCUMULATIONS AROUND AN INCH IN PLACES. THE BIG HORN BASIN SHOULD
SEE SOME LIGHT SNOW TONIGHT...ENDING BY SUNDAY MORNING. THE WIND
RIVER BASIN SHOULD SEE SOME LIGHT SNOW AT TIMES LATE THIS EVENING TO
AROUND SUNRISE SUNDAY. LESS THAN AN INCH IS EXPECTED FOR THE MOST
PARTS IN THE THOSE BASINS. OUT WEST NOT MUCH EXPECTED ASIDE FROM
SOME MOUNTAIN SNOW SHOWERS OVER THE NORTHWEST MOUNTAINS AND WIND
RIVER MOUNTAINS. WILL HAVE TO DEAL WITH THE FOG AND LOW CLOUDS IN
THE STAR VALLEY AGAIN TONIGHT INTO SUNDAY MORNING. COLDER LOWS EAST
OF THE DIVIDE AS THE BRUNT OF THE COLD AIR WILL REMAIN EAST OF THE
DIVIDE TONIGHT AND SUNDAY. CLOUDS WILL BE ON THE DECREASE SUNDAY
EAST OF THE DIVIDE AS THE SYSTEM DEPARTS. SOME HIGH CLOUDS WILL
FILTER IN SUNDAY PM IN THE NORTHWEST FLOW ALOFT. OUT WEST...SUNDAY
WILL BE DRY FOR MOST OF THE DAY. INCREASING CLOUDS SUNDAY AFTERNOON
WITH SCATTERED LIGHT SNOW FOR THE NORTHWEST WY MOUNTAINS AS MOISTURE
INCREASES IN THE NW FLOW ALOFT. IT SHOULD STAY DRY IN THE WESTERN
VALLEYS THROUGH 00Z MONDAY. HIGHS ON SUNDAY WILL BE 5 TO 10 DEGREES
COLDER THAN SATURDAY EAST OF THE DIVIDE AND SLIGHTLY COLDER WEST OF
THE DIVIDE.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

THROUGH THE FIRST PORTION OF THE LONG TERM FORECAST...MAINLY THROUGH
TUESDAY...REMAINS OF AN OLD SHOW ON PBS MANY YEARS AGO. THE SHOW IS
UPSTAIRS DOWNSTAIRS. EXPECT...THIS IS THE WEATHER VERSION CALLED
UPSLOPE DOWNSLOPE. IN AREAS WEST OF THE DIVIDE...THEY WILL BE IN THE
UPSLOPE PORTION OF THE FORECAST. THE FIRST SHORTWAVE APPROACHES FROM
THE WEST FOR SUNDAY NIGHT WITH THE FIRST SHOT OF POTENTIAL
ACCUMULATING SNOW. THE NEXT WAVE THEN ARRIVES SOMETIME ON MONDAY.
THE MODELS DO HAVE A FEW TIMING DIFFERENCES WITH THE NAM HAVING A
BIT OF A BREAK ON MONDAY AND THE GFS KEEPING THE PRECIPITATION GOING
THROUGH MUCH OF THE DAY. AT THIS POINT...CONTINUITY LOOKED
REASONABLE SO WE MADE FEW CHANGES. MEANWHILE...EAST OF THE DIVIDE IS
ON THE DOWNSLOPE SIDE. THIS MEANS MAINLY DRY CONDITIONS FOR MOST
LOCATIONS EXPECT FOR THE BIGHORN RANGE AND POSSIBLY THE NORTHERN BIG
HORN BASIN WHERE SOME JET ENERGY COULD BRING SOME LIGHT
PRECIPITATION. WITH THE DOWNSLOPING FLOW...EXPECT TEMPERATURES TO BE
NEAR TO ABOVE NORMAL FOR MOST LOCATIONS. THERE MAY BE THE POTENTIAL
FOR SOME HIGH WINDS...ESPECIALLY MONDAY NIGHT WITH A COUPLE OF
MODELS SHOWING 700 MILLIBAR WINDS AT OR OVER 50 KNOTS...ESPECIALLY
NEAR THE FAVORED AREAS LIKE NEAR CLARK AND PORTIONS OF NATRONA
COUNTY.

THE NEXT DECENT CHANCE FOR PRECIPITATION ACROSS THE AREA WOULD BE
TUESDAY NIGHT INTO WEDNESDAY. BOTH THE GFS AND EUROPEAN SHOW SOME
PRECIPITATION GETTING KICKED ACROSS THE DIVIDE AS A COLD FRONT AND
ASSOCIATED SHORT WAVE DROPS SOUTHWARD OUT OF CANADA AND INTO WYOMING
WITH MAYBE SOME LIGHT UPSLOPE EAST OF THE DIVIDE. AT THIS
POINT...THIS DOES NOT LOOK LIKE A BIG EVENT BUT THERE WILL BE THE
POTENTIAL FOR SOME PRECIPITATION EVERYWHERE. THERE ARE SOME
DIFFERENCES IN THE MODELS TIMING THE SYSTEMS WITH THE GFS MOVING
PRECIPITATION OUT FASTER THAN THE GFS AT THIS POINT.

BOTH THE GFS AND EUROPEAN NOW BUILD RIDGING ACROSS THE AREA FOR LATE
NEXT WEEK WITH MAINLY DRY CONDITIONS DOMINATING FOR THURSDAY AND
EVEN INTO FRIDAY. WE STILL HAVE SOME LIGHT POPS ACROSS THE WEST BUT
FUTURE SHIFTS MAY WANT TO REMOVE IT. WITH THE RIDGING...THE PATTERN
OF ABOVE NORMAL TEMPERATURES WILL CONTINUE WITH SOME 50S POSSIBLE BY
FRIDAY IN WARMER AREAS EAST OF THE DIVIDE. THEN BOTH MODELS SHOW THE
NEXT SYSTEM MOVING IN FOR NEXT WEEKEND.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

CLOUDS WILL LOWER OVER NORTHERN WY WITH AREAS OF LIGHT SNOW
DEVELOPING AROUND 00Z THROUGH 09Z BEFORE IT ENDS AND CONDITIONS
IMPROVE BY 12Z. EXPECT MVFR TO IFR CONDITIONS THROUGH 15Z WITH VFR
CONDITIONS AFTER 15Z SUNDAY. FOR THE CENTRAL AREA FROM KCPR TO
KLND THE LOWER CLOUDS AND AREAS OF LIGHT SNOW WILL OCCUR AROUND
03Z AND CONTINUE THROUGH 12Z. EXPECT MVFR TO IFR CONDITIONS
THROUGH 15Z...THEN CONDITIONS WILL IMPROVE AFTER 15Z WITH VFR
CONDITIONS PREVAILING BY 18Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

SOME FOG AND LOW CLOUDS WILL OCCUR IN THE STAR VALLEY TONIGHT INTO
SUNDAY MORNING WITH IFR CONDITIONS UNTIL 17Z. A COLD FRONT MAY PUSH
LOWER MVFR/IFR CIGS INTO VCNTY KRKS AFTER 07Z TONIGHT. ISOLATED
SNOW SHOWERS ARE EXPECTED OVER THE NORTHWEST MOUNTAINS AND OVER
THE WIND RIVER MOUNTAINS TONIGHT UNTIL 12Z SUNDAY. LOCAL MVFR
CONDITIONS WILL OCCUR IN THESE MOUNTAINS. VFR CONDITIONS WILL
PREVAIL SUNDAY AT THE TERMINAL SITES. SOME LIGHT SNOW FORMS OVER
THE NORTHWEST MOUNTAINS AFTER 20Z SUNDAY WITH SOME MVFR CONDITIONS
DEVELOPING BY 00Z MONDAY IN NW WY.

&&

.FIRE WEATHER...

A WEATHER SYSTEM WILL BRING SOME LIGHT SNOW EAST OF THE DIVIDE
TONIGHT AND SUNDAY MORNING. THEN MOSTLY DRY SUNDAY AFTERNOON
THROUGH MONDAY EAST OF THE DIVIDE. WEST OF THE DIVIDE WILL BE DRY
TONIGHT AND SUNDAY MORNING. LIGHT SNOW DEVELOPS OVER THE NORTHWEST
MOUNTAINS SUNDAY AFTERNOON. PERIODS OF SNOW FOR THE WESTERN
MOUNTAINS AND FAR WEST VALLEYS SUNDAY NIGHT THROUGH MONDAY NIGHT.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...AR
LONG TERM...HATTINGS
AVIATION...AR
FIRE WEATHER...AR






000
FXUS63 KUNR 312050
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
150 PM MST SAT JAN 31 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 148 PM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS.
PHASING NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL SUPPORT
CYCLOGENESIS ACROSS THE CENTRAL PLAINS...WITH A DEVELOPING
DEFORMATION ZONE NW OF THE LOW. THE FA WILL SEE INFLUENCE FROM BOTH
OF THESE SYSTEMS WITH THE NORTHERN COUNTERPART AFFECTING MOST OF
THE FA...WHILE SCENTRAL SD WILL SEE AN INFLUENCE FROM BOTH. BACKDOOR
COLD FRONT HAS SPREAD SW ACROSS THE FA...WITH FG AND AREAS OF ZL IN
ITS WAKE. EXPECTING FG AND ZL TO TAPPER OFF LATE THIS AFTERNOON AND
EARLY EVENING AS THERMAL PROFILES COOL AND ICE NUCLEATION ENSUES.
IN ADDITION...SEEDER FEEDER FROM DEVELOPING SNOWS WILL ALSO SCOUR
AVAILABLE NUCLEI. MAIN STORY WILL BE SNOWS TONIGHT. STRONG UPPER
JET STREAK ASSOCIATED WITH THE NORTHERN STREAM SHORTWAVE WILL COMBINE
WITH AN ASSOCIATED ARCTIC FRONT TO SUPPORT SNOWS ACROSS MOST OF EH
FA TONIGHT...SPREADING QUICKLY SE FROM NW SD THIS EVENING. MUCH OF
WESTERN SD AND PORTIONS OF NE WY WILL SEE AROUND AN INCH TO 2 INCHES
OF SNOW...POSSIBLY NEAR 3 IN THE FAR NE NEAR LEMMON. THE NORTHERN
BLACK HILLS AND FOOTHILLS WILL ALSO SEE SOME UPSLOPE
ENHANCEMENT...WITH CLOSER TO 3 INCHES POSSIBLE THERE. MOST OF THE
SNOW WILL FALL THIS EVENING...WITH RESIDUAL LIGHT SNOW THE REMAINDER
OF THE NIGHT.

A LITTLE DIFFERENT PROCESS EXPECTED OVER SCENTRAL SD. MASSIVE SW
CONUS UPPER LOW WILL EJECT INTO THE CENTRAL PLAINS AND CONTINUE TO
SUPPORT VIGOROUS CYCLOGENESIS IN THE EASTERN CENTRAL PLAINS AND
MIDWEST. MOIST CONVEYOR BELT ASSOCIATED WITH THIS PROCESS WILL
SUPPORT A STRENGTHENING DEFORMATION ZONE ACROSS CENTRAL NE INTO
SCENTRAL SD TONIGHT...WHERE LOCALLY ENHANCED SNOW RATES CAN BE
EXPECTED. IN ADDITION...PHASING NORTHERN STREAM IMPULSE WILL SUPPORT
A BRIEF STALL/PIVOT OF THE MOISTURE CONVEYOR BELT AND ASSOCIATED
DEFORMATION ZONE/FGEN...SUPPORTING A 2-4 HOUR EXTENSION OF DECENT
SNOWFALL. BOTTOM LINE EXPECTING 2-5 INCHES ACROSS MELLETTE...TODD
AND ESP TRIPP COUNTIES. LOCALLY HIGHER AMOUNTS COULD BE POSSIBLE IF
THE ENTIRE PROCESS SHIFTS A BIT FARTHER NW AND PAUSES LONGER. SNOW
WILL WIND DOWN QUICKLY SUNDAY MORNING WITH CLEARING SUNDAY AFTERNOON
MOST IF NOT ALL PLACES. A BRIEF SKIRT OF ARCTIC AIR WILL SUPPORT
MUCH COLDER TEMPERATURES ACROSS THE FA THROUGH SUNDAY. ACTIVE NW FLOW
WILL PERSIST WITH A LL BAROCLINIC ZONE REMAINING ACROSS THE FA. THE
NEXT IN A SERIES OF IMPULSES WILL ARRIVE LATE SUNDAY NIGHT...AND MAY
SUPPORT SNOW TOWARD DAWN MONDAY ACROSS THE FAR NW.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA
THROUGH THE EXTENDED FORECAST PERIOD. A RELATIVELY WEAK SHORTWAVE
WILL BRING A CHANCE OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY
AND TUESDAY. A BETTER DEFINED UPPER TROUGH/JET STREAK WILL AFFECT
THE AREA ON TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH AT THE
SURFACE...BRINGING A CHANCE OF SNOW TO THE AREA. AT THIS TIME IT
LOOKS LIKE THE BEST AREA FOR MEASURABLE SNOW ACCUMULATION WOULD BE
OVER PARTS OF NORTHEASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA.
SNOW MAY LINGER INTO WEDNESDAY ACROSS THE SOUTHWESTERN CWA...BUT DRY
WEATHER IS THEN EXPECTED THROUGH THE REST OF THE WEEK AS A RIDGE
BUILDS OVER THE WESTERN CONUS.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...ESPECIALLY ACROSS THE SOUTHWEST HALF OF THE
CWA. BELOW NORMAL TEMPS ARE EXPECTED ON WEDNESDAY AS THE BOUNDARY
SHIFTS SOUTH. WESTERLY WINDS WILL AID IN SIGNIFICANT WARMING FOR THE
END OF THE WEEK.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

FOG AND -FZDZ OVER MUCH OF WESTERN SD WILL CREATE
IFR/LIFR CIGS/VSBY THROUGH THE AFTERNOON. LIGHT SNOW WILL SPREAD
ACROSS THE AREA LATE THIS AFTERNOON THROUGH TONIGHT...RESULTING IN
WIDESPREAD IFR CONDITIONS. CIGS/VSBY WILL IMPROVE SUNDAY MORNING AS
SNOW TRANSITIONS EASTWARD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR SDZ046-047-049.

WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...POJORLIE







000
FXUS63 KUNR 312050
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
150 PM MST SAT JAN 31 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 148 PM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS.
PHASING NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL SUPPORT
CYCLOGENESIS ACROSS THE CENTRAL PLAINS...WITH A DEVELOPING
DEFORMATION ZONE NW OF THE LOW. THE FA WILL SEE INFLUENCE FROM BOTH
OF THESE SYSTEMS WITH THE NORTHERN COUNTERPART AFFECTING MOST OF
THE FA...WHILE SCENTRAL SD WILL SEE AN INFLUENCE FROM BOTH. BACKDOOR
COLD FRONT HAS SPREAD SW ACROSS THE FA...WITH FG AND AREAS OF ZL IN
ITS WAKE. EXPECTING FG AND ZL TO TAPPER OFF LATE THIS AFTERNOON AND
EARLY EVENING AS THERMAL PROFILES COOL AND ICE NUCLEATION ENSUES.
IN ADDITION...SEEDER FEEDER FROM DEVELOPING SNOWS WILL ALSO SCOUR
AVAILABLE NUCLEI. MAIN STORY WILL BE SNOWS TONIGHT. STRONG UPPER
JET STREAK ASSOCIATED WITH THE NORTHERN STREAM SHORTWAVE WILL COMBINE
WITH AN ASSOCIATED ARCTIC FRONT TO SUPPORT SNOWS ACROSS MOST OF EH
FA TONIGHT...SPREADING QUICKLY SE FROM NW SD THIS EVENING. MUCH OF
WESTERN SD AND PORTIONS OF NE WY WILL SEE AROUND AN INCH TO 2 INCHES
OF SNOW...POSSIBLY NEAR 3 IN THE FAR NE NEAR LEMMON. THE NORTHERN
BLACK HILLS AND FOOTHILLS WILL ALSO SEE SOME UPSLOPE
ENHANCEMENT...WITH CLOSER TO 3 INCHES POSSIBLE THERE. MOST OF THE
SNOW WILL FALL THIS EVENING...WITH RESIDUAL LIGHT SNOW THE REMAINDER
OF THE NIGHT.

A LITTLE DIFFERENT PROCESS EXPECTED OVER SCENTRAL SD. MASSIVE SW
CONUS UPPER LOW WILL EJECT INTO THE CENTRAL PLAINS AND CONTINUE TO
SUPPORT VIGOROUS CYCLOGENESIS IN THE EASTERN CENTRAL PLAINS AND
MIDWEST. MOIST CONVEYOR BELT ASSOCIATED WITH THIS PROCESS WILL
SUPPORT A STRENGTHENING DEFORMATION ZONE ACROSS CENTRAL NE INTO
SCENTRAL SD TONIGHT...WHERE LOCALLY ENHANCED SNOW RATES CAN BE
EXPECTED. IN ADDITION...PHASING NORTHERN STREAM IMPULSE WILL SUPPORT
A BRIEF STALL/PIVOT OF THE MOISTURE CONVEYOR BELT AND ASSOCIATED
DEFORMATION ZONE/FGEN...SUPPORTING A 2-4 HOUR EXTENSION OF DECENT
SNOWFALL. BOTTOM LINE EXPECTING 2-5 INCHES ACROSS MELLETTE...TODD
AND ESP TRIPP COUNTIES. LOCALLY HIGHER AMOUNTS COULD BE POSSIBLE IF
THE ENTIRE PROCESS SHIFTS A BIT FARTHER NW AND PAUSES LONGER. SNOW
WILL WIND DOWN QUICKLY SUNDAY MORNING WITH CLEARING SUNDAY AFTERNOON
MOST IF NOT ALL PLACES. A BRIEF SKIRT OF ARCTIC AIR WILL SUPPORT
MUCH COLDER TEMPERATURES ACROSS THE FA THROUGH SUNDAY. ACTIVE NW FLOW
WILL PERSIST WITH A LL BAROCLINIC ZONE REMAINING ACROSS THE FA. THE
NEXT IN A SERIES OF IMPULSES WILL ARRIVE LATE SUNDAY NIGHT...AND MAY
SUPPORT SNOW TOWARD DAWN MONDAY ACROSS THE FAR NW.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA
THROUGH THE EXTENDED FORECAST PERIOD. A RELATIVELY WEAK SHORTWAVE
WILL BRING A CHANCE OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY
AND TUESDAY. A BETTER DEFINED UPPER TROUGH/JET STREAK WILL AFFECT
THE AREA ON TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH AT THE
SURFACE...BRINGING A CHANCE OF SNOW TO THE AREA. AT THIS TIME IT
LOOKS LIKE THE BEST AREA FOR MEASURABLE SNOW ACCUMULATION WOULD BE
OVER PARTS OF NORTHEASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA.
SNOW MAY LINGER INTO WEDNESDAY ACROSS THE SOUTHWESTERN CWA...BUT DRY
WEATHER IS THEN EXPECTED THROUGH THE REST OF THE WEEK AS A RIDGE
BUILDS OVER THE WESTERN CONUS.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...ESPECIALLY ACROSS THE SOUTHWEST HALF OF THE
CWA. BELOW NORMAL TEMPS ARE EXPECTED ON WEDNESDAY AS THE BOUNDARY
SHIFTS SOUTH. WESTERLY WINDS WILL AID IN SIGNIFICANT WARMING FOR THE
END OF THE WEEK.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

FOG AND -FZDZ OVER MUCH OF WESTERN SD WILL CREATE
IFR/LIFR CIGS/VSBY THROUGH THE AFTERNOON. LIGHT SNOW WILL SPREAD
ACROSS THE AREA LATE THIS AFTERNOON THROUGH TONIGHT...RESULTING IN
WIDESPREAD IFR CONDITIONS. CIGS/VSBY WILL IMPROVE SUNDAY MORNING AS
SNOW TRANSITIONS EASTWARD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR SDZ046-047-049.

WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...POJORLIE







000
FXUS63 KUNR 312050
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
150 PM MST SAT JAN 31 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 148 PM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS.
PHASING NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL SUPPORT
CYCLOGENESIS ACROSS THE CENTRAL PLAINS...WITH A DEVELOPING
DEFORMATION ZONE NW OF THE LOW. THE FA WILL SEE INFLUENCE FROM BOTH
OF THESE SYSTEMS WITH THE NORTHERN COUNTERPART AFFECTING MOST OF
THE FA...WHILE SCENTRAL SD WILL SEE AN INFLUENCE FROM BOTH. BACKDOOR
COLD FRONT HAS SPREAD SW ACROSS THE FA...WITH FG AND AREAS OF ZL IN
ITS WAKE. EXPECTING FG AND ZL TO TAPPER OFF LATE THIS AFTERNOON AND
EARLY EVENING AS THERMAL PROFILES COOL AND ICE NUCLEATION ENSUES.
IN ADDITION...SEEDER FEEDER FROM DEVELOPING SNOWS WILL ALSO SCOUR
AVAILABLE NUCLEI. MAIN STORY WILL BE SNOWS TONIGHT. STRONG UPPER
JET STREAK ASSOCIATED WITH THE NORTHERN STREAM SHORTWAVE WILL COMBINE
WITH AN ASSOCIATED ARCTIC FRONT TO SUPPORT SNOWS ACROSS MOST OF EH
FA TONIGHT...SPREADING QUICKLY SE FROM NW SD THIS EVENING. MUCH OF
WESTERN SD AND PORTIONS OF NE WY WILL SEE AROUND AN INCH TO 2 INCHES
OF SNOW...POSSIBLY NEAR 3 IN THE FAR NE NEAR LEMMON. THE NORTHERN
BLACK HILLS AND FOOTHILLS WILL ALSO SEE SOME UPSLOPE
ENHANCEMENT...WITH CLOSER TO 3 INCHES POSSIBLE THERE. MOST OF THE
SNOW WILL FALL THIS EVENING...WITH RESIDUAL LIGHT SNOW THE REMAINDER
OF THE NIGHT.

A LITTLE DIFFERENT PROCESS EXPECTED OVER SCENTRAL SD. MASSIVE SW
CONUS UPPER LOW WILL EJECT INTO THE CENTRAL PLAINS AND CONTINUE TO
SUPPORT VIGOROUS CYCLOGENESIS IN THE EASTERN CENTRAL PLAINS AND
MIDWEST. MOIST CONVEYOR BELT ASSOCIATED WITH THIS PROCESS WILL
SUPPORT A STRENGTHENING DEFORMATION ZONE ACROSS CENTRAL NE INTO
SCENTRAL SD TONIGHT...WHERE LOCALLY ENHANCED SNOW RATES CAN BE
EXPECTED. IN ADDITION...PHASING NORTHERN STREAM IMPULSE WILL SUPPORT
A BRIEF STALL/PIVOT OF THE MOISTURE CONVEYOR BELT AND ASSOCIATED
DEFORMATION ZONE/FGEN...SUPPORTING A 2-4 HOUR EXTENSION OF DECENT
SNOWFALL. BOTTOM LINE EXPECTING 2-5 INCHES ACROSS MELLETTE...TODD
AND ESP TRIPP COUNTIES. LOCALLY HIGHER AMOUNTS COULD BE POSSIBLE IF
THE ENTIRE PROCESS SHIFTS A BIT FARTHER NW AND PAUSES LONGER. SNOW
WILL WIND DOWN QUICKLY SUNDAY MORNING WITH CLEARING SUNDAY AFTERNOON
MOST IF NOT ALL PLACES. A BRIEF SKIRT OF ARCTIC AIR WILL SUPPORT
MUCH COLDER TEMPERATURES ACROSS THE FA THROUGH SUNDAY. ACTIVE NW FLOW
WILL PERSIST WITH A LL BAROCLINIC ZONE REMAINING ACROSS THE FA. THE
NEXT IN A SERIES OF IMPULSES WILL ARRIVE LATE SUNDAY NIGHT...AND MAY
SUPPORT SNOW TOWARD DAWN MONDAY ACROSS THE FAR NW.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA
THROUGH THE EXTENDED FORECAST PERIOD. A RELATIVELY WEAK SHORTWAVE
WILL BRING A CHANCE OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY
AND TUESDAY. A BETTER DEFINED UPPER TROUGH/JET STREAK WILL AFFECT
THE AREA ON TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH AT THE
SURFACE...BRINGING A CHANCE OF SNOW TO THE AREA. AT THIS TIME IT
LOOKS LIKE THE BEST AREA FOR MEASURABLE SNOW ACCUMULATION WOULD BE
OVER PARTS OF NORTHEASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA.
SNOW MAY LINGER INTO WEDNESDAY ACROSS THE SOUTHWESTERN CWA...BUT DRY
WEATHER IS THEN EXPECTED THROUGH THE REST OF THE WEEK AS A RIDGE
BUILDS OVER THE WESTERN CONUS.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...ESPECIALLY ACROSS THE SOUTHWEST HALF OF THE
CWA. BELOW NORMAL TEMPS ARE EXPECTED ON WEDNESDAY AS THE BOUNDARY
SHIFTS SOUTH. WESTERLY WINDS WILL AID IN SIGNIFICANT WARMING FOR THE
END OF THE WEEK.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

FOG AND -FZDZ OVER MUCH OF WESTERN SD WILL CREATE
IFR/LIFR CIGS/VSBY THROUGH THE AFTERNOON. LIGHT SNOW WILL SPREAD
ACROSS THE AREA LATE THIS AFTERNOON THROUGH TONIGHT...RESULTING IN
WIDESPREAD IFR CONDITIONS. CIGS/VSBY WILL IMPROVE SUNDAY MORNING AS
SNOW TRANSITIONS EASTWARD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR SDZ046-047-049.

WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...POJORLIE







000
FXUS63 KUNR 312050
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
150 PM MST SAT JAN 31 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 148 PM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS.
PHASING NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL SUPPORT
CYCLOGENESIS ACROSS THE CENTRAL PLAINS...WITH A DEVELOPING
DEFORMATION ZONE NW OF THE LOW. THE FA WILL SEE INFLUENCE FROM BOTH
OF THESE SYSTEMS WITH THE NORTHERN COUNTERPART AFFECTING MOST OF
THE FA...WHILE SCENTRAL SD WILL SEE AN INFLUENCE FROM BOTH. BACKDOOR
COLD FRONT HAS SPREAD SW ACROSS THE FA...WITH FG AND AREAS OF ZL IN
ITS WAKE. EXPECTING FG AND ZL TO TAPPER OFF LATE THIS AFTERNOON AND
EARLY EVENING AS THERMAL PROFILES COOL AND ICE NUCLEATION ENSUES.
IN ADDITION...SEEDER FEEDER FROM DEVELOPING SNOWS WILL ALSO SCOUR
AVAILABLE NUCLEI. MAIN STORY WILL BE SNOWS TONIGHT. STRONG UPPER
JET STREAK ASSOCIATED WITH THE NORTHERN STREAM SHORTWAVE WILL COMBINE
WITH AN ASSOCIATED ARCTIC FRONT TO SUPPORT SNOWS ACROSS MOST OF EH
FA TONIGHT...SPREADING QUICKLY SE FROM NW SD THIS EVENING. MUCH OF
WESTERN SD AND PORTIONS OF NE WY WILL SEE AROUND AN INCH TO 2 INCHES
OF SNOW...POSSIBLY NEAR 3 IN THE FAR NE NEAR LEMMON. THE NORTHERN
BLACK HILLS AND FOOTHILLS WILL ALSO SEE SOME UPSLOPE
ENHANCEMENT...WITH CLOSER TO 3 INCHES POSSIBLE THERE. MOST OF THE
SNOW WILL FALL THIS EVENING...WITH RESIDUAL LIGHT SNOW THE REMAINDER
OF THE NIGHT.

A LITTLE DIFFERENT PROCESS EXPECTED OVER SCENTRAL SD. MASSIVE SW
CONUS UPPER LOW WILL EJECT INTO THE CENTRAL PLAINS AND CONTINUE TO
SUPPORT VIGOROUS CYCLOGENESIS IN THE EASTERN CENTRAL PLAINS AND
MIDWEST. MOIST CONVEYOR BELT ASSOCIATED WITH THIS PROCESS WILL
SUPPORT A STRENGTHENING DEFORMATION ZONE ACROSS CENTRAL NE INTO
SCENTRAL SD TONIGHT...WHERE LOCALLY ENHANCED SNOW RATES CAN BE
EXPECTED. IN ADDITION...PHASING NORTHERN STREAM IMPULSE WILL SUPPORT
A BRIEF STALL/PIVOT OF THE MOISTURE CONVEYOR BELT AND ASSOCIATED
DEFORMATION ZONE/FGEN...SUPPORTING A 2-4 HOUR EXTENSION OF DECENT
SNOWFALL. BOTTOM LINE EXPECTING 2-5 INCHES ACROSS MELLETTE...TODD
AND ESP TRIPP COUNTIES. LOCALLY HIGHER AMOUNTS COULD BE POSSIBLE IF
THE ENTIRE PROCESS SHIFTS A BIT FARTHER NW AND PAUSES LONGER. SNOW
WILL WIND DOWN QUICKLY SUNDAY MORNING WITH CLEARING SUNDAY AFTERNOON
MOST IF NOT ALL PLACES. A BRIEF SKIRT OF ARCTIC AIR WILL SUPPORT
MUCH COLDER TEMPERATURES ACROSS THE FA THROUGH SUNDAY. ACTIVE NW FLOW
WILL PERSIST WITH A LL BAROCLINIC ZONE REMAINING ACROSS THE FA. THE
NEXT IN A SERIES OF IMPULSES WILL ARRIVE LATE SUNDAY NIGHT...AND MAY
SUPPORT SNOW TOWARD DAWN MONDAY ACROSS THE FAR NW.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA
THROUGH THE EXTENDED FORECAST PERIOD. A RELATIVELY WEAK SHORTWAVE
WILL BRING A CHANCE OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY
AND TUESDAY. A BETTER DEFINED UPPER TROUGH/JET STREAK WILL AFFECT
THE AREA ON TUESDAY NIGHT AS A COLD FRONT MOVES THROUGH AT THE
SURFACE...BRINGING A CHANCE OF SNOW TO THE AREA. AT THIS TIME IT
LOOKS LIKE THE BEST AREA FOR MEASURABLE SNOW ACCUMULATION WOULD BE
OVER PARTS OF NORTHEASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA.
SNOW MAY LINGER INTO WEDNESDAY ACROSS THE SOUTHWESTERN CWA...BUT DRY
WEATHER IS THEN EXPECTED THROUGH THE REST OF THE WEEK AS A RIDGE
BUILDS OVER THE WESTERN CONUS.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...ESPECIALLY ACROSS THE SOUTHWEST HALF OF THE
CWA. BELOW NORMAL TEMPS ARE EXPECTED ON WEDNESDAY AS THE BOUNDARY
SHIFTS SOUTH. WESTERLY WINDS WILL AID IN SIGNIFICANT WARMING FOR THE
END OF THE WEEK.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 148 PM MST SAT JAN 31 2015

FOG AND -FZDZ OVER MUCH OF WESTERN SD WILL CREATE
IFR/LIFR CIGS/VSBY THROUGH THE AFTERNOON. LIGHT SNOW WILL SPREAD
ACROSS THE AREA LATE THIS AFTERNOON THROUGH TONIGHT...RESULTING IN
WIDESPREAD IFR CONDITIONS. CIGS/VSBY WILL IMPROVE SUNDAY MORNING AS
SNOW TRANSITIONS EASTWARD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY UNTIL 6 AM CST SUNDAY FOR SDZ046-047-049.

WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...POJORLIE







000
FXUS65 KRIW 312011
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
111 PM MST SAT JAN 31 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT (ISSUED AT 250 AM MST)

ANY LEFT OVER SNOWFALL IN SOUTHERN SWEETWATER COUNTY THIS MORNING
WILL SHUT OFF SHORTLY AFTER SUNRISE AS THE LOW OVER VEGAS PROPAGATES
SOUTH TO OLD MEXICO. THE ASCT HIGH AND MID CLOUDS THAT HAVE BEEN
OVER CENTRAL AND SOUTHERN WY FRIDAY WILL CLEAR OUT OF SWEETWATER AND
NATRONA COUNTIES TO THE SOUTHEAST WITH MOSTLY CLEAR SKIES BY 18Z
TODAY. OTHERWISE EXPECT A MOSTLY SUNNY DAY WITH LIGHT WINDS AND
RELATIVELY MILD TEMPERATURES TODAY. THE NORTHERN STREAM VORT OVER
SOUTHERN BC WILL TRACK ACROSS WY FROM THE NW BY 00Z SAT. THIS
WEATHER FEATURE WILL DELIVER PATCHY LIGHT SNOW TO AREAS NORTH AND
EAST OF THE DIVIDE TONIGHT AS IT DRIVES A COLD FRONT SOUTH AND H7
TEMPS DROP TO -16C IN JOHNSON COUNTY BY 12Z SUNDAY. POST FRONTAL NNW
WINDS WILL INCREASE IN JOHNSON COUNTY LATE TODAY. SUNDAY WILL BE
RELATIVELY CHILLY WITH WARM AIR ADVECTING IN ALOFT FROM THE
SOUTHWEST SO THE COOLER AIR WILL BE SHORT LIVED. NORTHERN AND
WESTERN WY MAY NOT BREAK FREEZING SUNDAY BEFORE WARMING BACK UP
MONDAY. STILL...SEASONABLE TEMPS SLATED FOR THIS TIME OF YEAR
SUNDAY. BY SUNDAY NIGHT THE STEERING FLOW WILL BACK FROM NW TO WEST
AND INCREASE IN SPEED...MORE DIRECTLY OFF THE PACIFIC  UNDER A
FLATTENING RIDGE. A BATCH OF PACIFIC MOISTURE COMBINED WITH A WEAK
VORT EMBEDDED IN THE BACKING FLOW...SNOW WILL INCREASE IN THE WEST
SUNDAY NIGHT. SNOW WILL LESSEN IN INTENSITY MONDAY IN THE FAR WEST.
THEN THE CIRCULATION NOW WELL OFF THE PACIFIC COAST AT 45N/152W WILL
ARRIVE AS A VIGOROUS SHORTWAVE BRINGING ANOTHER SLUG OF PACIFIC
MOISTURE ACROSS MT/WY MONDAY NIGHT WITH SNOWFALL INCREASING ONCE
AGAIN IN THE FAR WEST. WITH FAVORABLE UPSLOPE CONDITIONS FOR THE FAR
WEST SUNDAY NIGHT THROUGH MONDAY NIGHT WITH THESE TWO BACK TO BACK
PACIFIC SYSTEMS...THERE WILL BE A POTENTIAL OF ACCUMULATING SNOWFALL
FOR THE FAR WEST AND WILL HAVE TO BE MONITORED. THERE WILL BE SOME
ISENTROPIC LIFT IN THE FAR WEST MONDAY NIGHT AS WELL WITH THE SECOND
PACIFIC SYSTEM.

.LONG TERM...TUESDAY THROUGH SATURDAY

THE OVERALL BIG PICTURE IS REASONABLY SIMILAR IN THE MODELS TONIGHT
BUT THE TIMING/SPEED VARIES ENOUGH TO MAKE THE FORECAST A CHALLENGE.
OVERALL...IT STILL LOOKS LIKE A COLD SHORTWAVE AND ASSOCIATED COLD
FRONT WILL DROP SOUTH OUT OF CANADA ON TUESDAY INTO TUESDAY NIGHT
WITH POTENTIAL FOR UPSLOPE EAST OF THE DIVIDE...ESPECIALLY IN THE
NORTH. IN THE WEST...A MOIST W-NW FLOW WILL KEEP SNOW FLYING OUT
THERE WITH STRONG W-NW WIND AHEAD OF THE CANADIAN FRONT EAST OF THE
DIVIDE. GFS HAS MORE AMPLIFICATION OF THE UPSTREAM RIDGE WEDNESDAY
WITH A COLDER...CYCLONIC NW FLOW WHILE THE ECMWF PUSHES THE RIDGE
AXIS MORE QUICKLY OFF TO THE EAST WITH LESS AMPLIFICATION. THE GEM
IS MORE OF A COMPROMISE. WILL GRADUALLY PUSH THE POPS SWD INTO
WEDNESDAY TO MAINLY COVER THE WEST AND SOUTH HALF. AS THE RIDGE AXIS
STARTS TO MOVE IN WEDNESDAY NIGHT SOME ISENTROPIC UPGLIDE MAY BE
ENOUGH FOR SOME LIGHT MTN SNOWFALL OUT WEST. DRIEST DAY IS SHAPING
UP TO BE THURSDAY WITH RIDGE AXIS INTO THE WEST. ECMWF KEEPS THE DRY
RIDGE AXIS OVER US THROUGH FRIDAY WHILE THE GFS IS FLATTER AND MORE
MOIST WITH PERSISTENT AT LEAST LIGHT PCPN OUT WEST. DUE TO THE
UNCERTAINTY THIS FAR OUT WILL KEEP JUST SOME POPS OUT WEST.
POTENTIAL FOR VALLEY RAIN OR SNOW AND MOUNTAIN SNOW INCREASING ONCE
AGAIN BY SATURDAY WITH POTENTIAL SHORTWAVE OR TWO SPINNING OFF THE
ERN PACIFIC TROUGH AND MOVING EAST ACROSS THE AREA. OVERALL...THIS
PATTERN COULD KEEP AREAS EAST OF THE DIVIDE MIXED OFF AND ON WITH
MILD TEMPERATURES. WINDY AHEAD OF THE CANADIAN FRONT TUESDAY. BRIEF
COLDER AIR WEDNESDAY WITH DECENT SURFACE HIGH JUST TO THE NE...THEN
WARM AIR ALOFT MOVING IN AGAIN BY THURSDAY THROUGH SATURDAY WITH
POTENTIAL FOR ENOUGH FLOW ALOFT AND PRESSURE GRADIENT TO KEEP
QUITE A FEW AREAS EAST OF THE DIVIDE MIXED...ESPECIALLY FRIDAY AND
SATURDAY. GENERALLY GOING WITH 40S AND SOME 50S EAST OF THE DIVIDE
FOR FRIDAY AND SATURDAY. COOLER IN THE WEST WITH INVERSIONS
HOLDING IN BETWEEN SYSTEMS AND THEN OF COURSE COLD RAIN OR SNOW AT
TIMES WITH EACH SYSTEM. SO MAINLY 30S OUT WEST.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

A COLD FRONT WILL PUSH SOUTH ACROSS NORTHERN WYOMING THIS AFTERNOON.
AREAS OF LOWER MVFR/IFR CIGS AND -SN WILL FOLLOW THE FRONT INTO
NORTHERN WYOMING AFTER 22Z...AND SOUTHWARD TO NEAR A VCNTY KRIW-KCPR
LINE BY 03Z SUNDAY. AREAS OF LOWER MVFR/IFR CIGS...LCL LIFR CIGS/FG
WILL LIKELY REMAIN AGAINST THE EAST SLOPES OF THE DIVIDE THROUGH 12Z
SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

PATCHY FOG WILL LINGER IN THE STAR VALLEY THIS AFTERNOON AND REFORM
AGAIN AFTER 03Z THIS EVENING...EXPECT MVFR TO LIFR CONDITIONS AROUND
THE AFTON AIRPORT UNTIL 16Z SUNDAY. A COLD FRONT MAY PUSH LOWER
MVFR/IFR CIGS INTO VCNTY KRKS AFTER 06Z SUNDAY. ISOLATED SNOW
SHOWERS ARE POSSIBLE OVER THE NORTHWEST MOUNTAINS AND OVER THE WIND
RIVER MOUNTAINS AFTER 03Z SUNDAY UNTIL 13Z SUNDAY WITH LOCAL MVFR
CONDITIONS.

&&

.FIRE WEATHER...

FIRE DANGER IS LOW FOR ALL AREAS...AND WILL REMAIN SO THROUGH NEXT
WEEK. MEASURABLE PRECIPITATION WILL NOT FALL ACROSS THE FORECAST
AREA UNTIL LATE TODAY INTO SUNDAY MORNING EAST OF THE DIVIDE.
FROM SUNDAY NIGHT THROUGH THE NEXT WORK WEEK...A SERIES OF
DISTURBANCES WILL RIDE THROUGH THE REGION...AFFECTING MAINLY THE
WESTERN AND NORTHERN DISPATCH ZONES. TODAY WILL SEE IMPROVEMENT
IN BOTH MIXING ABILITY AND DISPERSION...ESPECIALLY EAST OF THE
DIVIDE AND ACROSS THE SOUTHERN ZONES.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AR
FIRE WEATHER...LIPSON











000
FXUS65 KRIW 312011
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
111 PM MST SAT JAN 31 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT (ISSUED AT 250 AM MST)

ANY LEFT OVER SNOWFALL IN SOUTHERN SWEETWATER COUNTY THIS MORNING
WILL SHUT OFF SHORTLY AFTER SUNRISE AS THE LOW OVER VEGAS PROPAGATES
SOUTH TO OLD MEXICO. THE ASCT HIGH AND MID CLOUDS THAT HAVE BEEN
OVER CENTRAL AND SOUTHERN WY FRIDAY WILL CLEAR OUT OF SWEETWATER AND
NATRONA COUNTIES TO THE SOUTHEAST WITH MOSTLY CLEAR SKIES BY 18Z
TODAY. OTHERWISE EXPECT A MOSTLY SUNNY DAY WITH LIGHT WINDS AND
RELATIVELY MILD TEMPERATURES TODAY. THE NORTHERN STREAM VORT OVER
SOUTHERN BC WILL TRACK ACROSS WY FROM THE NW BY 00Z SAT. THIS
WEATHER FEATURE WILL DELIVER PATCHY LIGHT SNOW TO AREAS NORTH AND
EAST OF THE DIVIDE TONIGHT AS IT DRIVES A COLD FRONT SOUTH AND H7
TEMPS DROP TO -16C IN JOHNSON COUNTY BY 12Z SUNDAY. POST FRONTAL NNW
WINDS WILL INCREASE IN JOHNSON COUNTY LATE TODAY. SUNDAY WILL BE
RELATIVELY CHILLY WITH WARM AIR ADVECTING IN ALOFT FROM THE
SOUTHWEST SO THE COOLER AIR WILL BE SHORT LIVED. NORTHERN AND
WESTERN WY MAY NOT BREAK FREEZING SUNDAY BEFORE WARMING BACK UP
MONDAY. STILL...SEASONABLE TEMPS SLATED FOR THIS TIME OF YEAR
SUNDAY. BY SUNDAY NIGHT THE STEERING FLOW WILL BACK FROM NW TO WEST
AND INCREASE IN SPEED...MORE DIRECTLY OFF THE PACIFIC  UNDER A
FLATTENING RIDGE. A BATCH OF PACIFIC MOISTURE COMBINED WITH A WEAK
VORT EMBEDDED IN THE BACKING FLOW...SNOW WILL INCREASE IN THE WEST
SUNDAY NIGHT. SNOW WILL LESSEN IN INTENSITY MONDAY IN THE FAR WEST.
THEN THE CIRCULATION NOW WELL OFF THE PACIFIC COAST AT 45N/152W WILL
ARRIVE AS A VIGOROUS SHORTWAVE BRINGING ANOTHER SLUG OF PACIFIC
MOISTURE ACROSS MT/WY MONDAY NIGHT WITH SNOWFALL INCREASING ONCE
AGAIN IN THE FAR WEST. WITH FAVORABLE UPSLOPE CONDITIONS FOR THE FAR
WEST SUNDAY NIGHT THROUGH MONDAY NIGHT WITH THESE TWO BACK TO BACK
PACIFIC SYSTEMS...THERE WILL BE A POTENTIAL OF ACCUMULATING SNOWFALL
FOR THE FAR WEST AND WILL HAVE TO BE MONITORED. THERE WILL BE SOME
ISENTROPIC LIFT IN THE FAR WEST MONDAY NIGHT AS WELL WITH THE SECOND
PACIFIC SYSTEM.

.LONG TERM...TUESDAY THROUGH SATURDAY

THE OVERALL BIG PICTURE IS REASONABLY SIMILAR IN THE MODELS TONIGHT
BUT THE TIMING/SPEED VARIES ENOUGH TO MAKE THE FORECAST A CHALLENGE.
OVERALL...IT STILL LOOKS LIKE A COLD SHORTWAVE AND ASSOCIATED COLD
FRONT WILL DROP SOUTH OUT OF CANADA ON TUESDAY INTO TUESDAY NIGHT
WITH POTENTIAL FOR UPSLOPE EAST OF THE DIVIDE...ESPECIALLY IN THE
NORTH. IN THE WEST...A MOIST W-NW FLOW WILL KEEP SNOW FLYING OUT
THERE WITH STRONG W-NW WIND AHEAD OF THE CANADIAN FRONT EAST OF THE
DIVIDE. GFS HAS MORE AMPLIFICATION OF THE UPSTREAM RIDGE WEDNESDAY
WITH A COLDER...CYCLONIC NW FLOW WHILE THE ECMWF PUSHES THE RIDGE
AXIS MORE QUICKLY OFF TO THE EAST WITH LESS AMPLIFICATION. THE GEM
IS MORE OF A COMPROMISE. WILL GRADUALLY PUSH THE POPS SWD INTO
WEDNESDAY TO MAINLY COVER THE WEST AND SOUTH HALF. AS THE RIDGE AXIS
STARTS TO MOVE IN WEDNESDAY NIGHT SOME ISENTROPIC UPGLIDE MAY BE
ENOUGH FOR SOME LIGHT MTN SNOWFALL OUT WEST. DRIEST DAY IS SHAPING
UP TO BE THURSDAY WITH RIDGE AXIS INTO THE WEST. ECMWF KEEPS THE DRY
RIDGE AXIS OVER US THROUGH FRIDAY WHILE THE GFS IS FLATTER AND MORE
MOIST WITH PERSISTENT AT LEAST LIGHT PCPN OUT WEST. DUE TO THE
UNCERTAINTY THIS FAR OUT WILL KEEP JUST SOME POPS OUT WEST.
POTENTIAL FOR VALLEY RAIN OR SNOW AND MOUNTAIN SNOW INCREASING ONCE
AGAIN BY SATURDAY WITH POTENTIAL SHORTWAVE OR TWO SPINNING OFF THE
ERN PACIFIC TROUGH AND MOVING EAST ACROSS THE AREA. OVERALL...THIS
PATTERN COULD KEEP AREAS EAST OF THE DIVIDE MIXED OFF AND ON WITH
MILD TEMPERATURES. WINDY AHEAD OF THE CANADIAN FRONT TUESDAY. BRIEF
COLDER AIR WEDNESDAY WITH DECENT SURFACE HIGH JUST TO THE NE...THEN
WARM AIR ALOFT MOVING IN AGAIN BY THURSDAY THROUGH SATURDAY WITH
POTENTIAL FOR ENOUGH FLOW ALOFT AND PRESSURE GRADIENT TO KEEP
QUITE A FEW AREAS EAST OF THE DIVIDE MIXED...ESPECIALLY FRIDAY AND
SATURDAY. GENERALLY GOING WITH 40S AND SOME 50S EAST OF THE DIVIDE
FOR FRIDAY AND SATURDAY. COOLER IN THE WEST WITH INVERSIONS
HOLDING IN BETWEEN SYSTEMS AND THEN OF COURSE COLD RAIN OR SNOW AT
TIMES WITH EACH SYSTEM. SO MAINLY 30S OUT WEST.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

A COLD FRONT WILL PUSH SOUTH ACROSS NORTHERN WYOMING THIS AFTERNOON.
AREAS OF LOWER MVFR/IFR CIGS AND -SN WILL FOLLOW THE FRONT INTO
NORTHERN WYOMING AFTER 22Z...AND SOUTHWARD TO NEAR A VCNTY KRIW-KCPR
LINE BY 03Z SUNDAY. AREAS OF LOWER MVFR/IFR CIGS...LCL LIFR CIGS/FG
WILL LIKELY REMAIN AGAINST THE EAST SLOPES OF THE DIVIDE THROUGH 12Z
SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

PATCHY FOG WILL LINGER IN THE STAR VALLEY THIS AFTERNOON AND REFORM
AGAIN AFTER 03Z THIS EVENING...EXPECT MVFR TO LIFR CONDITIONS AROUND
THE AFTON AIRPORT UNTIL 16Z SUNDAY. A COLD FRONT MAY PUSH LOWER
MVFR/IFR CIGS INTO VCNTY KRKS AFTER 06Z SUNDAY. ISOLATED SNOW
SHOWERS ARE POSSIBLE OVER THE NORTHWEST MOUNTAINS AND OVER THE WIND
RIVER MOUNTAINS AFTER 03Z SUNDAY UNTIL 13Z SUNDAY WITH LOCAL MVFR
CONDITIONS.

&&

.FIRE WEATHER...

FIRE DANGER IS LOW FOR ALL AREAS...AND WILL REMAIN SO THROUGH NEXT
WEEK. MEASURABLE PRECIPITATION WILL NOT FALL ACROSS THE FORECAST
AREA UNTIL LATE TODAY INTO SUNDAY MORNING EAST OF THE DIVIDE.
FROM SUNDAY NIGHT THROUGH THE NEXT WORK WEEK...A SERIES OF
DISTURBANCES WILL RIDE THROUGH THE REGION...AFFECTING MAINLY THE
WESTERN AND NORTHERN DISPATCH ZONES. TODAY WILL SEE IMPROVEMENT
IN BOTH MIXING ABILITY AND DISPERSION...ESPECIALLY EAST OF THE
DIVIDE AND ACROSS THE SOUTHERN ZONES.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AR
FIRE WEATHER...LIPSON











000
FXUS65 KRIW 312011
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
111 PM MST SAT JAN 31 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT (ISSUED AT 250 AM MST)

ANY LEFT OVER SNOWFALL IN SOUTHERN SWEETWATER COUNTY THIS MORNING
WILL SHUT OFF SHORTLY AFTER SUNRISE AS THE LOW OVER VEGAS PROPAGATES
SOUTH TO OLD MEXICO. THE ASCT HIGH AND MID CLOUDS THAT HAVE BEEN
OVER CENTRAL AND SOUTHERN WY FRIDAY WILL CLEAR OUT OF SWEETWATER AND
NATRONA COUNTIES TO THE SOUTHEAST WITH MOSTLY CLEAR SKIES BY 18Z
TODAY. OTHERWISE EXPECT A MOSTLY SUNNY DAY WITH LIGHT WINDS AND
RELATIVELY MILD TEMPERATURES TODAY. THE NORTHERN STREAM VORT OVER
SOUTHERN BC WILL TRACK ACROSS WY FROM THE NW BY 00Z SAT. THIS
WEATHER FEATURE WILL DELIVER PATCHY LIGHT SNOW TO AREAS NORTH AND
EAST OF THE DIVIDE TONIGHT AS IT DRIVES A COLD FRONT SOUTH AND H7
TEMPS DROP TO -16C IN JOHNSON COUNTY BY 12Z SUNDAY. POST FRONTAL NNW
WINDS WILL INCREASE IN JOHNSON COUNTY LATE TODAY. SUNDAY WILL BE
RELATIVELY CHILLY WITH WARM AIR ADVECTING IN ALOFT FROM THE
SOUTHWEST SO THE COOLER AIR WILL BE SHORT LIVED. NORTHERN AND
WESTERN WY MAY NOT BREAK FREEZING SUNDAY BEFORE WARMING BACK UP
MONDAY. STILL...SEASONABLE TEMPS SLATED FOR THIS TIME OF YEAR
SUNDAY. BY SUNDAY NIGHT THE STEERING FLOW WILL BACK FROM NW TO WEST
AND INCREASE IN SPEED...MORE DIRECTLY OFF THE PACIFIC  UNDER A
FLATTENING RIDGE. A BATCH OF PACIFIC MOISTURE COMBINED WITH A WEAK
VORT EMBEDDED IN THE BACKING FLOW...SNOW WILL INCREASE IN THE WEST
SUNDAY NIGHT. SNOW WILL LESSEN IN INTENSITY MONDAY IN THE FAR WEST.
THEN THE CIRCULATION NOW WELL OFF THE PACIFIC COAST AT 45N/152W WILL
ARRIVE AS A VIGOROUS SHORTWAVE BRINGING ANOTHER SLUG OF PACIFIC
MOISTURE ACROSS MT/WY MONDAY NIGHT WITH SNOWFALL INCREASING ONCE
AGAIN IN THE FAR WEST. WITH FAVORABLE UPSLOPE CONDITIONS FOR THE FAR
WEST SUNDAY NIGHT THROUGH MONDAY NIGHT WITH THESE TWO BACK TO BACK
PACIFIC SYSTEMS...THERE WILL BE A POTENTIAL OF ACCUMULATING SNOWFALL
FOR THE FAR WEST AND WILL HAVE TO BE MONITORED. THERE WILL BE SOME
ISENTROPIC LIFT IN THE FAR WEST MONDAY NIGHT AS WELL WITH THE SECOND
PACIFIC SYSTEM.

.LONG TERM...TUESDAY THROUGH SATURDAY

THE OVERALL BIG PICTURE IS REASONABLY SIMILAR IN THE MODELS TONIGHT
BUT THE TIMING/SPEED VARIES ENOUGH TO MAKE THE FORECAST A CHALLENGE.
OVERALL...IT STILL LOOKS LIKE A COLD SHORTWAVE AND ASSOCIATED COLD
FRONT WILL DROP SOUTH OUT OF CANADA ON TUESDAY INTO TUESDAY NIGHT
WITH POTENTIAL FOR UPSLOPE EAST OF THE DIVIDE...ESPECIALLY IN THE
NORTH. IN THE WEST...A MOIST W-NW FLOW WILL KEEP SNOW FLYING OUT
THERE WITH STRONG W-NW WIND AHEAD OF THE CANADIAN FRONT EAST OF THE
DIVIDE. GFS HAS MORE AMPLIFICATION OF THE UPSTREAM RIDGE WEDNESDAY
WITH A COLDER...CYCLONIC NW FLOW WHILE THE ECMWF PUSHES THE RIDGE
AXIS MORE QUICKLY OFF TO THE EAST WITH LESS AMPLIFICATION. THE GEM
IS MORE OF A COMPROMISE. WILL GRADUALLY PUSH THE POPS SWD INTO
WEDNESDAY TO MAINLY COVER THE WEST AND SOUTH HALF. AS THE RIDGE AXIS
STARTS TO MOVE IN WEDNESDAY NIGHT SOME ISENTROPIC UPGLIDE MAY BE
ENOUGH FOR SOME LIGHT MTN SNOWFALL OUT WEST. DRIEST DAY IS SHAPING
UP TO BE THURSDAY WITH RIDGE AXIS INTO THE WEST. ECMWF KEEPS THE DRY
RIDGE AXIS OVER US THROUGH FRIDAY WHILE THE GFS IS FLATTER AND MORE
MOIST WITH PERSISTENT AT LEAST LIGHT PCPN OUT WEST. DUE TO THE
UNCERTAINTY THIS FAR OUT WILL KEEP JUST SOME POPS OUT WEST.
POTENTIAL FOR VALLEY RAIN OR SNOW AND MOUNTAIN SNOW INCREASING ONCE
AGAIN BY SATURDAY WITH POTENTIAL SHORTWAVE OR TWO SPINNING OFF THE
ERN PACIFIC TROUGH AND MOVING EAST ACROSS THE AREA. OVERALL...THIS
PATTERN COULD KEEP AREAS EAST OF THE DIVIDE MIXED OFF AND ON WITH
MILD TEMPERATURES. WINDY AHEAD OF THE CANADIAN FRONT TUESDAY. BRIEF
COLDER AIR WEDNESDAY WITH DECENT SURFACE HIGH JUST TO THE NE...THEN
WARM AIR ALOFT MOVING IN AGAIN BY THURSDAY THROUGH SATURDAY WITH
POTENTIAL FOR ENOUGH FLOW ALOFT AND PRESSURE GRADIENT TO KEEP
QUITE A FEW AREAS EAST OF THE DIVIDE MIXED...ESPECIALLY FRIDAY AND
SATURDAY. GENERALLY GOING WITH 40S AND SOME 50S EAST OF THE DIVIDE
FOR FRIDAY AND SATURDAY. COOLER IN THE WEST WITH INVERSIONS
HOLDING IN BETWEEN SYSTEMS AND THEN OF COURSE COLD RAIN OR SNOW AT
TIMES WITH EACH SYSTEM. SO MAINLY 30S OUT WEST.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

A COLD FRONT WILL PUSH SOUTH ACROSS NORTHERN WYOMING THIS AFTERNOON.
AREAS OF LOWER MVFR/IFR CIGS AND -SN WILL FOLLOW THE FRONT INTO
NORTHERN WYOMING AFTER 22Z...AND SOUTHWARD TO NEAR A VCNTY KRIW-KCPR
LINE BY 03Z SUNDAY. AREAS OF LOWER MVFR/IFR CIGS...LCL LIFR CIGS/FG
WILL LIKELY REMAIN AGAINST THE EAST SLOPES OF THE DIVIDE THROUGH 12Z
SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

PATCHY FOG WILL LINGER IN THE STAR VALLEY THIS AFTERNOON AND REFORM
AGAIN AFTER 03Z THIS EVENING...EXPECT MVFR TO LIFR CONDITIONS AROUND
THE AFTON AIRPORT UNTIL 16Z SUNDAY. A COLD FRONT MAY PUSH LOWER
MVFR/IFR CIGS INTO VCNTY KRKS AFTER 06Z SUNDAY. ISOLATED SNOW
SHOWERS ARE POSSIBLE OVER THE NORTHWEST MOUNTAINS AND OVER THE WIND
RIVER MOUNTAINS AFTER 03Z SUNDAY UNTIL 13Z SUNDAY WITH LOCAL MVFR
CONDITIONS.

&&

.FIRE WEATHER...

FIRE DANGER IS LOW FOR ALL AREAS...AND WILL REMAIN SO THROUGH NEXT
WEEK. MEASURABLE PRECIPITATION WILL NOT FALL ACROSS THE FORECAST
AREA UNTIL LATE TODAY INTO SUNDAY MORNING EAST OF THE DIVIDE.
FROM SUNDAY NIGHT THROUGH THE NEXT WORK WEEK...A SERIES OF
DISTURBANCES WILL RIDE THROUGH THE REGION...AFFECTING MAINLY THE
WESTERN AND NORTHERN DISPATCH ZONES. TODAY WILL SEE IMPROVEMENT
IN BOTH MIXING ABILITY AND DISPERSION...ESPECIALLY EAST OF THE
DIVIDE AND ACROSS THE SOUTHERN ZONES.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AR
FIRE WEATHER...LIPSON











000
FXUS65 KRIW 312011
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
111 PM MST SAT JAN 31 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT (ISSUED AT 250 AM MST)

ANY LEFT OVER SNOWFALL IN SOUTHERN SWEETWATER COUNTY THIS MORNING
WILL SHUT OFF SHORTLY AFTER SUNRISE AS THE LOW OVER VEGAS PROPAGATES
SOUTH TO OLD MEXICO. THE ASCT HIGH AND MID CLOUDS THAT HAVE BEEN
OVER CENTRAL AND SOUTHERN WY FRIDAY WILL CLEAR OUT OF SWEETWATER AND
NATRONA COUNTIES TO THE SOUTHEAST WITH MOSTLY CLEAR SKIES BY 18Z
TODAY. OTHERWISE EXPECT A MOSTLY SUNNY DAY WITH LIGHT WINDS AND
RELATIVELY MILD TEMPERATURES TODAY. THE NORTHERN STREAM VORT OVER
SOUTHERN BC WILL TRACK ACROSS WY FROM THE NW BY 00Z SAT. THIS
WEATHER FEATURE WILL DELIVER PATCHY LIGHT SNOW TO AREAS NORTH AND
EAST OF THE DIVIDE TONIGHT AS IT DRIVES A COLD FRONT SOUTH AND H7
TEMPS DROP TO -16C IN JOHNSON COUNTY BY 12Z SUNDAY. POST FRONTAL NNW
WINDS WILL INCREASE IN JOHNSON COUNTY LATE TODAY. SUNDAY WILL BE
RELATIVELY CHILLY WITH WARM AIR ADVECTING IN ALOFT FROM THE
SOUTHWEST SO THE COOLER AIR WILL BE SHORT LIVED. NORTHERN AND
WESTERN WY MAY NOT BREAK FREEZING SUNDAY BEFORE WARMING BACK UP
MONDAY. STILL...SEASONABLE TEMPS SLATED FOR THIS TIME OF YEAR
SUNDAY. BY SUNDAY NIGHT THE STEERING FLOW WILL BACK FROM NW TO WEST
AND INCREASE IN SPEED...MORE DIRECTLY OFF THE PACIFIC  UNDER A
FLATTENING RIDGE. A BATCH OF PACIFIC MOISTURE COMBINED WITH A WEAK
VORT EMBEDDED IN THE BACKING FLOW...SNOW WILL INCREASE IN THE WEST
SUNDAY NIGHT. SNOW WILL LESSEN IN INTENSITY MONDAY IN THE FAR WEST.
THEN THE CIRCULATION NOW WELL OFF THE PACIFIC COAST AT 45N/152W WILL
ARRIVE AS A VIGOROUS SHORTWAVE BRINGING ANOTHER SLUG OF PACIFIC
MOISTURE ACROSS MT/WY MONDAY NIGHT WITH SNOWFALL INCREASING ONCE
AGAIN IN THE FAR WEST. WITH FAVORABLE UPSLOPE CONDITIONS FOR THE FAR
WEST SUNDAY NIGHT THROUGH MONDAY NIGHT WITH THESE TWO BACK TO BACK
PACIFIC SYSTEMS...THERE WILL BE A POTENTIAL OF ACCUMULATING SNOWFALL
FOR THE FAR WEST AND WILL HAVE TO BE MONITORED. THERE WILL BE SOME
ISENTROPIC LIFT IN THE FAR WEST MONDAY NIGHT AS WELL WITH THE SECOND
PACIFIC SYSTEM.

.LONG TERM...TUESDAY THROUGH SATURDAY

THE OVERALL BIG PICTURE IS REASONABLY SIMILAR IN THE MODELS TONIGHT
BUT THE TIMING/SPEED VARIES ENOUGH TO MAKE THE FORECAST A CHALLENGE.
OVERALL...IT STILL LOOKS LIKE A COLD SHORTWAVE AND ASSOCIATED COLD
FRONT WILL DROP SOUTH OUT OF CANADA ON TUESDAY INTO TUESDAY NIGHT
WITH POTENTIAL FOR UPSLOPE EAST OF THE DIVIDE...ESPECIALLY IN THE
NORTH. IN THE WEST...A MOIST W-NW FLOW WILL KEEP SNOW FLYING OUT
THERE WITH STRONG W-NW WIND AHEAD OF THE CANADIAN FRONT EAST OF THE
DIVIDE. GFS HAS MORE AMPLIFICATION OF THE UPSTREAM RIDGE WEDNESDAY
WITH A COLDER...CYCLONIC NW FLOW WHILE THE ECMWF PUSHES THE RIDGE
AXIS MORE QUICKLY OFF TO THE EAST WITH LESS AMPLIFICATION. THE GEM
IS MORE OF A COMPROMISE. WILL GRADUALLY PUSH THE POPS SWD INTO
WEDNESDAY TO MAINLY COVER THE WEST AND SOUTH HALF. AS THE RIDGE AXIS
STARTS TO MOVE IN WEDNESDAY NIGHT SOME ISENTROPIC UPGLIDE MAY BE
ENOUGH FOR SOME LIGHT MTN SNOWFALL OUT WEST. DRIEST DAY IS SHAPING
UP TO BE THURSDAY WITH RIDGE AXIS INTO THE WEST. ECMWF KEEPS THE DRY
RIDGE AXIS OVER US THROUGH FRIDAY WHILE THE GFS IS FLATTER AND MORE
MOIST WITH PERSISTENT AT LEAST LIGHT PCPN OUT WEST. DUE TO THE
UNCERTAINTY THIS FAR OUT WILL KEEP JUST SOME POPS OUT WEST.
POTENTIAL FOR VALLEY RAIN OR SNOW AND MOUNTAIN SNOW INCREASING ONCE
AGAIN BY SATURDAY WITH POTENTIAL SHORTWAVE OR TWO SPINNING OFF THE
ERN PACIFIC TROUGH AND MOVING EAST ACROSS THE AREA. OVERALL...THIS
PATTERN COULD KEEP AREAS EAST OF THE DIVIDE MIXED OFF AND ON WITH
MILD TEMPERATURES. WINDY AHEAD OF THE CANADIAN FRONT TUESDAY. BRIEF
COLDER AIR WEDNESDAY WITH DECENT SURFACE HIGH JUST TO THE NE...THEN
WARM AIR ALOFT MOVING IN AGAIN BY THURSDAY THROUGH SATURDAY WITH
POTENTIAL FOR ENOUGH FLOW ALOFT AND PRESSURE GRADIENT TO KEEP
QUITE A FEW AREAS EAST OF THE DIVIDE MIXED...ESPECIALLY FRIDAY AND
SATURDAY. GENERALLY GOING WITH 40S AND SOME 50S EAST OF THE DIVIDE
FOR FRIDAY AND SATURDAY. COOLER IN THE WEST WITH INVERSIONS
HOLDING IN BETWEEN SYSTEMS AND THEN OF COURSE COLD RAIN OR SNOW AT
TIMES WITH EACH SYSTEM. SO MAINLY 30S OUT WEST.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

A COLD FRONT WILL PUSH SOUTH ACROSS NORTHERN WYOMING THIS AFTERNOON.
AREAS OF LOWER MVFR/IFR CIGS AND -SN WILL FOLLOW THE FRONT INTO
NORTHERN WYOMING AFTER 22Z...AND SOUTHWARD TO NEAR A VCNTY KRIW-KCPR
LINE BY 03Z SUNDAY. AREAS OF LOWER MVFR/IFR CIGS...LCL LIFR CIGS/FG
WILL LIKELY REMAIN AGAINST THE EAST SLOPES OF THE DIVIDE THROUGH 12Z
SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

PATCHY FOG WILL LINGER IN THE STAR VALLEY THIS AFTERNOON AND REFORM
AGAIN AFTER 03Z THIS EVENING...EXPECT MVFR TO LIFR CONDITIONS AROUND
THE AFTON AIRPORT UNTIL 16Z SUNDAY. A COLD FRONT MAY PUSH LOWER
MVFR/IFR CIGS INTO VCNTY KRKS AFTER 06Z SUNDAY. ISOLATED SNOW
SHOWERS ARE POSSIBLE OVER THE NORTHWEST MOUNTAINS AND OVER THE WIND
RIVER MOUNTAINS AFTER 03Z SUNDAY UNTIL 13Z SUNDAY WITH LOCAL MVFR
CONDITIONS.

&&

.FIRE WEATHER...

FIRE DANGER IS LOW FOR ALL AREAS...AND WILL REMAIN SO THROUGH NEXT
WEEK. MEASURABLE PRECIPITATION WILL NOT FALL ACROSS THE FORECAST
AREA UNTIL LATE TODAY INTO SUNDAY MORNING EAST OF THE DIVIDE.
FROM SUNDAY NIGHT THROUGH THE NEXT WORK WEEK...A SERIES OF
DISTURBANCES WILL RIDE THROUGH THE REGION...AFFECTING MAINLY THE
WESTERN AND NORTHERN DISPATCH ZONES. TODAY WILL SEE IMPROVEMENT
IN BOTH MIXING ABILITY AND DISPERSION...ESPECIALLY EAST OF THE
DIVIDE AND ACROSS THE SOUTHERN ZONES.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AR
FIRE WEATHER...LIPSON











000
FXUS65 KCYS 311728
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1028 AM MST SAT JAN 31 2015

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 530 AM MST SAT JAN 31 2015

MADE A FEW CHANGES TO THE FORECAST FOR TODAY AS CURRENT WATER
VAPOR IMAGERY TRENDS SUGGEST ENERGY ASSOCIATED WITH THE SOUTHERN
STORM SYSTEM LOOKS TO LINGER OVER THE FORECAST AREA SLIGHTLY
LONGER THAN PREVIOUS THINKING. THE MIDLEVEL BAROCLINIC BAND ON
THE NORTHERN FRINGE OF THE UPPER LOW OVER THE DESERT SOUTHWEST IS
PROGGED TO REMAIN OVERHEAD THROUGH MIDDAY TODAY...WITH A SURFACE
TROUGH POSITIONED JUST SOUTHEAST OF THE FORECAST AREA EXTENDING
FROM CENTRAL COLORADO UP THRU CENTRAL NEBRASKA. SFC CYCLOGENESIS
OCCURRING OVER COLORADO TODAY WITHIN THIS TROUGH WILL PULL THE
MAIN COLD FRONT CURRENTLY OVER THE NORTHERN PLAINS SOUTH THRU THE
FORECAST AREA. SOUTHEASTERLY FLOW AT 700 MB OVER THE PLAINS AHEAD
OF THE MIDLEVEL FRONT WILL ADVECT IN SOME MOISTURE THIS MORNING
WITH WEAK ISENTROPIC LIFT DEVELOPING THROUGH THE DAY OVER THE
PANHANDLE AS THE SFC FRONT STEADILY SHIFTS SOUTH. THE MAIN PRECIP
BAND LOOKS TO DEVELOP OVER THE SOUTHERN PANHANDLE THIS MORNING
WITHIN THE AREA OF ISENTROPIC LIFT...AND THEN SHIFTS NORTH A BIT
INTO THE CENTRAL PANHANDLE THIS AFTERNOON BEFORE THE NORTHERN
STREAM SHORTWAVE FINALLY NUDGES THE MIDLEVEL FRONT AND ASSOCIATED
PRECIP BAND EAST EARLY THIS EVENING. SO BUMPED UP POPS AND SNOW
TOTALS ESPECIALLY ACROSS BOX BUTTE AND MORRILL COUNTIES WITHIN
MAIN AREA OF MIDLEVEL CONVERGENCE AND LIFT WHERE AROUND AN INCH OF
SNOW IS LIKELY THIS AFTERNOON. MODELS ALSO SHOW SOME WEAK
INSTABILITY IN THIS AREA AS WELL WHICH WILL AID IN OVERALL SHOWER
CHANCES. DO THINK PRECIP TYPE WILL BE MAJORITY SNOW BASED ON
TIMING OF THE SFC FRONT THIS MORNING...AND FORECAST SOUNDINGS
DEPICTING THE MAJORITY OF THE COLUMN WILL BE BELOW FREEZING.
CANNOT RULE OUT A MIX OF RAIN-SNOW AT THE ONSET OF PRECIP THO.
STILL EXPECTING SNOW SHOWERS TO CONTINUE IN THE SNOWY AND SIERRA
MADRES THIS MORNING AHEAD OF A SHORTWAVE MOVING UP FROM UTAH INTO
WESTERN CO.

THE NORTHERN STREAM SHORTWAVE TROUGH WILL SLIDE SOUTHEAST OVER THE
FORECAST AREA THIS EVENING WITH SHOWERS REDEVELOPING OVER MUCH OF
THE CWA THROUGH THE EVENING AND OVERNIGHT PERIOD. EXPECTING A
QUICK BURST OF SNOW WITH ANY SHOWER THAT OCCURS WITH ACCUMULATIONS
LOOKING TO GENERALLY BE ONE HALF INCH OR LESS IN THE LOWER
ELEVATIONS...AND AN INCH OR TWO IN THE MOUNTAINS. THE WAVE WILL
DEPART THE AREA QUICKLY SUNDAY MORNING WITH DRY AND COOLER
CONDITIONS ANTICIPATED FOR THE REST OF SUNDAY. HIGH PRESSURE WILL
BUILD OVER THE ROCKIES SUNDAY NIGHT WITH A WEAK DISTURBANCE MOVING
ATOP THE RIDGE AND OVER THE ROCKIES THROUGH THIS TIME. THE LEESIDE
PRESSURE TROUGH WILL DEEPEN QUITE RAPIDLY AHEAD OF THIS WAVE WITH
THE LLVL PRESSURE GRADIENT STRENGTHENING AS A RESULT. BY 06Z
MONDAY...THE CAG-CPR GRADIENT WILL BE ROUGHLY 55-60 DAM WITH WINDS
IN THE 750 TO 700 MB LAYER PROGGED TO BE IN EXCESS OF 50 KTS
THROUGH 12Z. A CROSS-SECTION PLOT THROUGH THE WIND PRONE AREAS
SHOW THE INVERSION SETTING UP JUST AROUND MOUNTAIN TOP LEVEL AND
WITHIN THE BAND OF STRONGER WINDS. SO...LOOKING AT PERHAPS A
MARGINAL HIGH WIND EVENT LATE SUNDAY NIGHT THROUGH MONDAY MORNING.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 530 AM MST SAT JAN 31 2015

THE EARLY PART OF NEXT WEEK WILL FEATURE WINDY CONDITIONS ACROSS
SOUTHEAST WYOMING AND INTERMITTENT SNOWS...MAINLY ACROSS THE MTNS.
THE LLVL CAG-CPR GRADIENT WILL BECOME HIGH ENOUGH (AROUND 60 METERS)
BY MON MORNING TO SUGGEST A MARGINAL HIGH WIND EVENT ACROSS THE WIND
PRONE AREAS.  HOWEVER...THE BETTER CHANCE OF HIGH WINDS WILL BE LATE
MON NIGHT INTO TUES AS THE LLVL GRADIENT INCREASES FURTHER TO 75-80
METERS AND FLOW ALOFT IS STRONGER.  THERE IS EVEN THE POTENTIAL FOR
HIGH WINDS TO SPREAD ONTO THE ADJACENT PLAINS OF SOUTHEAST WYOMING.
THE GRADIENT BEGINS TO DECREASE BY LATE TUES AS HIGHER PRESSURES AND
A COLD FRONT BACK INTO THE REGION.  TEMPS ON MON AND TUES WILL BE
ABOVE NORMAL WITH DOWNSLOPING WESTERLY WINDS PREVAILING.

THE OTHER STORY EARLY NEXT WEEK WILL BE THE OROGRAPHIC SNOWFALL
ACROSS THE SIERRA MADRE AND SNOWY RANGES.  MOIST NORTHWESTERLY FLOW
WILL TRANSPORT A GOOD AMOUNT OF PACIFIC MOISTURE INTO WYOMING.  BOTH
THE GFS AND ECMWF INDICATE A GOOD CHANCE OF SNOW THROUGH MIDDAY MON
AND THEN A BRIEF BREAK BEFORE MORE SNOW ARRIVES ON TUES AFTN.  SNOW
AMOUNTS (COMBINED WITH THE WINDY CONDITIONS) COULD WARRANT SOME SORT
OF WINTER WEATHER HEADLINE AT THAT TIME.  BY WED MORNING SNOW COULD
SPREAD ONTO THE PLAINS IN THE LLVL UPSLOPE BEHIND THE FRONT COMBINED
WITH SOME UPPER LEVEL SUPPORT. GENERALLY HAVE SLIGHT CHANCE POPS FOR
NOW ALONG WITH COOLER TEMPS.  IT IS A RATHER PROGRESSIVE PATTERN SO
INCREASING HEIGHTS AND TEMPS WILL OCCUR BY THURS AND FRI.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 1028 AM MST SAT JAN 31 2015

MAINLY VFR THIS AFTERNOON OVER KRWL AND KLAR TERMINALS BUT SHOULD
LOWER TO MVFR AND PATCHY IFR THIS EVENING.  OVER THE SE WY PLAINS
AND THE NEB PANHANDLE WIDESPREAD IFR AND SOME LIFR CIGS EXPECTED TO
PERSIST THROUGH TONIGHT WITH AREAS OF LIGHT SNOW IN WEAK UPSLOPE
FLOW.

&&

.FIRE WEATHER...
ISSUED AT 530 AM MST SAT JAN 31 2015

SNOW SHOWERS WILL PERSIST OVER THE SNOWY AND SIERRA MADRE
MOUNTAINS THROUGH MUCH OF TODAY...WHILE RAIN AND SNOW SHOWERS WILL
DEVELOP OVER THE PLAINS AND HIGH VALLEYS THIS AFTERNOON AND EVENING.
SNOW ACCUMULATIONS WILL REMAIN GENERALLY LIGHT. SUNDAY WILL
REMAIN COOL AND MOSTLY DRY WITH WINDY CONDITIONS RETURNING TO THE
WIND PRONE AREAS OF SOUTHEAST WYOMING LATE SUNDAY NIGHT. WARM AND
WINDY CONDITIONS WILL CONTINUE FOR THE DISTRICT THROUGH MIDWEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...ZF
AVIATION...RE
FIRE WEATHER...RJM



000
FXUS65 KCYS 311728
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1028 AM MST SAT JAN 31 2015

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 530 AM MST SAT JAN 31 2015

MADE A FEW CHANGES TO THE FORECAST FOR TODAY AS CURRENT WATER
VAPOR IMAGERY TRENDS SUGGEST ENERGY ASSOCIATED WITH THE SOUTHERN
STORM SYSTEM LOOKS TO LINGER OVER THE FORECAST AREA SLIGHTLY
LONGER THAN PREVIOUS THINKING. THE MIDLEVEL BAROCLINIC BAND ON
THE NORTHERN FRINGE OF THE UPPER LOW OVER THE DESERT SOUTHWEST IS
PROGGED TO REMAIN OVERHEAD THROUGH MIDDAY TODAY...WITH A SURFACE
TROUGH POSITIONED JUST SOUTHEAST OF THE FORECAST AREA EXTENDING
FROM CENTRAL COLORADO UP THRU CENTRAL NEBRASKA. SFC CYCLOGENESIS
OCCURRING OVER COLORADO TODAY WITHIN THIS TROUGH WILL PULL THE
MAIN COLD FRONT CURRENTLY OVER THE NORTHERN PLAINS SOUTH THRU THE
FORECAST AREA. SOUTHEASTERLY FLOW AT 700 MB OVER THE PLAINS AHEAD
OF THE MIDLEVEL FRONT WILL ADVECT IN SOME MOISTURE THIS MORNING
WITH WEAK ISENTROPIC LIFT DEVELOPING THROUGH THE DAY OVER THE
PANHANDLE AS THE SFC FRONT STEADILY SHIFTS SOUTH. THE MAIN PRECIP
BAND LOOKS TO DEVELOP OVER THE SOUTHERN PANHANDLE THIS MORNING
WITHIN THE AREA OF ISENTROPIC LIFT...AND THEN SHIFTS NORTH A BIT
INTO THE CENTRAL PANHANDLE THIS AFTERNOON BEFORE THE NORTHERN
STREAM SHORTWAVE FINALLY NUDGES THE MIDLEVEL FRONT AND ASSOCIATED
PRECIP BAND EAST EARLY THIS EVENING. SO BUMPED UP POPS AND SNOW
TOTALS ESPECIALLY ACROSS BOX BUTTE AND MORRILL COUNTIES WITHIN
MAIN AREA OF MIDLEVEL CONVERGENCE AND LIFT WHERE AROUND AN INCH OF
SNOW IS LIKELY THIS AFTERNOON. MODELS ALSO SHOW SOME WEAK
INSTABILITY IN THIS AREA AS WELL WHICH WILL AID IN OVERALL SHOWER
CHANCES. DO THINK PRECIP TYPE WILL BE MAJORITY SNOW BASED ON
TIMING OF THE SFC FRONT THIS MORNING...AND FORECAST SOUNDINGS
DEPICTING THE MAJORITY OF THE COLUMN WILL BE BELOW FREEZING.
CANNOT RULE OUT A MIX OF RAIN-SNOW AT THE ONSET OF PRECIP THO.
STILL EXPECTING SNOW SHOWERS TO CONTINUE IN THE SNOWY AND SIERRA
MADRES THIS MORNING AHEAD OF A SHORTWAVE MOVING UP FROM UTAH INTO
WESTERN CO.

THE NORTHERN STREAM SHORTWAVE TROUGH WILL SLIDE SOUTHEAST OVER THE
FORECAST AREA THIS EVENING WITH SHOWERS REDEVELOPING OVER MUCH OF
THE CWA THROUGH THE EVENING AND OVERNIGHT PERIOD. EXPECTING A
QUICK BURST OF SNOW WITH ANY SHOWER THAT OCCURS WITH ACCUMULATIONS
LOOKING TO GENERALLY BE ONE HALF INCH OR LESS IN THE LOWER
ELEVATIONS...AND AN INCH OR TWO IN THE MOUNTAINS. THE WAVE WILL
DEPART THE AREA QUICKLY SUNDAY MORNING WITH DRY AND COOLER
CONDITIONS ANTICIPATED FOR THE REST OF SUNDAY. HIGH PRESSURE WILL
BUILD OVER THE ROCKIES SUNDAY NIGHT WITH A WEAK DISTURBANCE MOVING
ATOP THE RIDGE AND OVER THE ROCKIES THROUGH THIS TIME. THE LEESIDE
PRESSURE TROUGH WILL DEEPEN QUITE RAPIDLY AHEAD OF THIS WAVE WITH
THE LLVL PRESSURE GRADIENT STRENGTHENING AS A RESULT. BY 06Z
MONDAY...THE CAG-CPR GRADIENT WILL BE ROUGHLY 55-60 DAM WITH WINDS
IN THE 750 TO 700 MB LAYER PROGGED TO BE IN EXCESS OF 50 KTS
THROUGH 12Z. A CROSS-SECTION PLOT THROUGH THE WIND PRONE AREAS
SHOW THE INVERSION SETTING UP JUST AROUND MOUNTAIN TOP LEVEL AND
WITHIN THE BAND OF STRONGER WINDS. SO...LOOKING AT PERHAPS A
MARGINAL HIGH WIND EVENT LATE SUNDAY NIGHT THROUGH MONDAY MORNING.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 530 AM MST SAT JAN 31 2015

THE EARLY PART OF NEXT WEEK WILL FEATURE WINDY CONDITIONS ACROSS
SOUTHEAST WYOMING AND INTERMITTENT SNOWS...MAINLY ACROSS THE MTNS.
THE LLVL CAG-CPR GRADIENT WILL BECOME HIGH ENOUGH (AROUND 60 METERS)
BY MON MORNING TO SUGGEST A MARGINAL HIGH WIND EVENT ACROSS THE WIND
PRONE AREAS.  HOWEVER...THE BETTER CHANCE OF HIGH WINDS WILL BE LATE
MON NIGHT INTO TUES AS THE LLVL GRADIENT INCREASES FURTHER TO 75-80
METERS AND FLOW ALOFT IS STRONGER.  THERE IS EVEN THE POTENTIAL FOR
HIGH WINDS TO SPREAD ONTO THE ADJACENT PLAINS OF SOUTHEAST WYOMING.
THE GRADIENT BEGINS TO DECREASE BY LATE TUES AS HIGHER PRESSURES AND
A COLD FRONT BACK INTO THE REGION.  TEMPS ON MON AND TUES WILL BE
ABOVE NORMAL WITH DOWNSLOPING WESTERLY WINDS PREVAILING.

THE OTHER STORY EARLY NEXT WEEK WILL BE THE OROGRAPHIC SNOWFALL
ACROSS THE SIERRA MADRE AND SNOWY RANGES.  MOIST NORTHWESTERLY FLOW
WILL TRANSPORT A GOOD AMOUNT OF PACIFIC MOISTURE INTO WYOMING.  BOTH
THE GFS AND ECMWF INDICATE A GOOD CHANCE OF SNOW THROUGH MIDDAY MON
AND THEN A BRIEF BREAK BEFORE MORE SNOW ARRIVES ON TUES AFTN.  SNOW
AMOUNTS (COMBINED WITH THE WINDY CONDITIONS) COULD WARRANT SOME SORT
OF WINTER WEATHER HEADLINE AT THAT TIME.  BY WED MORNING SNOW COULD
SPREAD ONTO THE PLAINS IN THE LLVL UPSLOPE BEHIND THE FRONT COMBINED
WITH SOME UPPER LEVEL SUPPORT. GENERALLY HAVE SLIGHT CHANCE POPS FOR
NOW ALONG WITH COOLER TEMPS.  IT IS A RATHER PROGRESSIVE PATTERN SO
INCREASING HEIGHTS AND TEMPS WILL OCCUR BY THURS AND FRI.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SUNDAY MORNING)
ISSUED AT 1028 AM MST SAT JAN 31 2015

MAINLY VFR THIS AFTERNOON OVER KRWL AND KLAR TERMINALS BUT SHOULD
LOWER TO MVFR AND PATCHY IFR THIS EVENING.  OVER THE SE WY PLAINS
AND THE NEB PANHANDLE WIDESPREAD IFR AND SOME LIFR CIGS EXPECTED TO
PERSIST THROUGH TONIGHT WITH AREAS OF LIGHT SNOW IN WEAK UPSLOPE
FLOW.

&&

.FIRE WEATHER...
ISSUED AT 530 AM MST SAT JAN 31 2015

SNOW SHOWERS WILL PERSIST OVER THE SNOWY AND SIERRA MADRE
MOUNTAINS THROUGH MUCH OF TODAY...WHILE RAIN AND SNOW SHOWERS WILL
DEVELOP OVER THE PLAINS AND HIGH VALLEYS THIS AFTERNOON AND EVENING.
SNOW ACCUMULATIONS WILL REMAIN GENERALLY LIGHT. SUNDAY WILL
REMAIN COOL AND MOSTLY DRY WITH WINDY CONDITIONS RETURNING TO THE
WIND PRONE AREAS OF SOUTHEAST WYOMING LATE SUNDAY NIGHT. WARM AND
WINDY CONDITIONS WILL CONTINUE FOR THE DISTRICT THROUGH MIDWEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...ZF
AVIATION...RE
FIRE WEATHER...RJM




000
FXUS63 KUNR 311658
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
958 AM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 823 AM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS THIS
MORNING. PHASING NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL
SUPPORT CYCLOGENESIS ACROSS THE CENTRAL PLAINS THIS
AFTERNOON...WITH A DEVELOPING DEFORMATION ZONE NW OF THE LOW. THIS
DEFORMATION ZONE IS PROGGED TO AFFECT SOUTH CENTRAL SD LATE THIS
AFTERNOON INTO TONIGHT. ABUNDANT MOISTURE WILL AVAILABLE WITH THIS
SYSTEM SUPPORTING A PERIOD OF DECENT SNOWS AS LIFT EXPANDS ACROSS
THE REGION TONIGHT. CURRENT EXPECTATION IS FOR 3-4 INCHES ACROSS
MUCH OF TRIPP COUNTY...WITH LOCALLY HIGHER AMOUNTS POSSIBLE ACROSS
THE SOUTHEAST PORTION OF THE COUNTY. HAVE ISSUED A WW ADV FOR
THIS.

&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 349 AM MST SAT JAN 31 2015

UPPER LEVEL ANALYSIS HAS UPPER LOW ACROSS THE SOUTHWEST CONUS WITH
NORTHWEST FLOW ACROSS THE NORTHERN CONUS. SKIES ARE CLOUDY ACROSS
THE NORTHERN PLAINS WITH LOW STRATUS DECK SLIDING SOUTH ACROSS THE
DAKOTAS. AT THE SURFACE...BACK-DOOR COLD FRONT IS CURRENTLY
DROPPING SOUTH ACROSS SOUTH DAKOTA...WITH WINDS TURNING NORTHEAST
BEHIND THE FRONT. TEMPERATURES ARE MAINLY IN THE 20S.

TODAY...UPPER RIDGE SHIFTS SOUTHEAST AS CUT-OFF LOW DEVELOPS
ACROSS THE SOUTHWEST CONUS. SURFACE COLD FRONT AND STRATUS DECK
WILL CONTINUE TO DROP SOUTHWEST ACROSS THE WESTERN SOUTH DAKOTA
PLAINS. COOLER AIR WILL FILTER INTO THE AREA BEHIND THE
FRONT...AND ALONG WITH THE CLOUD COVER...AREAS ACROSS THE SOUTH
DAKOTA PLAINS WILL REMAIN IN THE 20S FOR TODAY. FURTHER WEST IN
WYOMING...HIGH TEMPERATURES WILL BE MILDER...IN THE LOWER 40S.
STRONG NORTHERN STREAM IMPULSE WILL SLIDE THROUGH THE NORTHERN
PLAINS LATE TODAY INTO TONIGHT. THIS FEATURE WITH AN ASSOCIATED
STRONG JET STREAK WILL FORCE A PERIOD OF LIGHT SNOW OVER THE AREA
TONIGHT. IN ADDITION...A DEVELOPING SURFACE LOW WILL SKIRT SOUTH
CENTRAL SOUTH DAKOTA...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-3 INCH
RANGE...HIGHEST ACROSS THE NORTHERN BLACK HILLS AND ACROSS TRIPP
COUNTY.

SUNDAY...UPPER SHORTWAVE SHIFTS QUICKLY EAST...WITH SOME LIGHT
SNOW POSSIBLY LINGERING ACROSS THE NORTHERN BLACK HILLS AND FAR
SOUTH CENTRAL SOUTH DAKOTA DURING THE MORNING. WEAK UPPER RIDGE
BUILDS ACROSS THE ROCKIES WITH SKIES BECOMING MOSTLY SUNNY LATE
IN THE DAY. ARCTIC HIGH REMAINS ACROSS THE AREA WITH HIGH
TEMPERATURES ONLY IN THE TEENS ACROSS THE SOUTH DAKOTA
PLAINS...AND IN THE 20S ACROSS NORTHEAST WYOMING. LOWS SUNDAY
NIGHT WILL FALL INTO THE 5 TO 20 DEGREE RANGE.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 349 AM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD...BECOMING MORE ZONAL TOWARD THE END OF
THE WEEK. A RELATIVELY WEAK SHORTWAVE WILL BRING A SLIGHT CHANCE
OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY. A
BETTER DEFINED UPPER TROUGH WILL AFFECT THE AREA ON TUESDAY NIGHT
AS A COLD FRONT MOVES THROUGH AT THE SURFACE...BRINGING A CHANCE
OF SNOW TO THE AREA. AT THIS TIME IT LOOKS LIKE THE BEST AREA FOR
MEASURABLE SNOW ACCUMULATION WOULD BE OVER PARTS OF NORTHEASTERN
WYOMING AND SOUTHWESTERN SOUTH DAKOTA. DRY WEATHER IS THEN
EXPECTED THROUGH THE REST OF THE WEEK.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...THEN BECOMING COLDER THAN AVERAGE BEHIND THE
COLD FRONT ON WEDNESDAY. THE BOUNDARY WILL THEN SHIFT NORTHEASTWARD
AGAIN WITH MUCH WARMER THAN AVERAGE TEMPERATURES EXPECTED ON FRIDAY.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 956 AM MST SAT JAN 31 2015

LOW STRATUS/FOG OVER MUCH OF WESTERN SD WILL CREATE IFR/MVFR
CIGS/VSBY THROUGHOUT THE DAY. LIGHT SNOW WILL SPREAD ACROSS THE
AREA LATE THIS AFTERNOON THROUGH TONIGHT...RESULTING IN WIDESPREAD
IFR CONDITIONS. CIGS/VSBY WILL IMPROVE SUNDAY MORNING AS SNOW
TRANSITIONS EASTWARD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST
     SUNDAY FOR SDZ049.

WY...NONE.
&&

$$

UPDATE...JC
SHORT TERM...15
LONG TERM...10
AVIATION...POJORLIE






000
FXUS63 KUNR 311658
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
958 AM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 823 AM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS THIS
MORNING. PHASING NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL
SUPPORT CYCLOGENESIS ACROSS THE CENTRAL PLAINS THIS
AFTERNOON...WITH A DEVELOPING DEFORMATION ZONE NW OF THE LOW. THIS
DEFORMATION ZONE IS PROGGED TO AFFECT SOUTH CENTRAL SD LATE THIS
AFTERNOON INTO TONIGHT. ABUNDANT MOISTURE WILL AVAILABLE WITH THIS
SYSTEM SUPPORTING A PERIOD OF DECENT SNOWS AS LIFT EXPANDS ACROSS
THE REGION TONIGHT. CURRENT EXPECTATION IS FOR 3-4 INCHES ACROSS
MUCH OF TRIPP COUNTY...WITH LOCALLY HIGHER AMOUNTS POSSIBLE ACROSS
THE SOUTHEAST PORTION OF THE COUNTY. HAVE ISSUED A WW ADV FOR
THIS.

&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 349 AM MST SAT JAN 31 2015

UPPER LEVEL ANALYSIS HAS UPPER LOW ACROSS THE SOUTHWEST CONUS WITH
NORTHWEST FLOW ACROSS THE NORTHERN CONUS. SKIES ARE CLOUDY ACROSS
THE NORTHERN PLAINS WITH LOW STRATUS DECK SLIDING SOUTH ACROSS THE
DAKOTAS. AT THE SURFACE...BACK-DOOR COLD FRONT IS CURRENTLY
DROPPING SOUTH ACROSS SOUTH DAKOTA...WITH WINDS TURNING NORTHEAST
BEHIND THE FRONT. TEMPERATURES ARE MAINLY IN THE 20S.

TODAY...UPPER RIDGE SHIFTS SOUTHEAST AS CUT-OFF LOW DEVELOPS
ACROSS THE SOUTHWEST CONUS. SURFACE COLD FRONT AND STRATUS DECK
WILL CONTINUE TO DROP SOUTHWEST ACROSS THE WESTERN SOUTH DAKOTA
PLAINS. COOLER AIR WILL FILTER INTO THE AREA BEHIND THE
FRONT...AND ALONG WITH THE CLOUD COVER...AREAS ACROSS THE SOUTH
DAKOTA PLAINS WILL REMAIN IN THE 20S FOR TODAY. FURTHER WEST IN
WYOMING...HIGH TEMPERATURES WILL BE MILDER...IN THE LOWER 40S.
STRONG NORTHERN STREAM IMPULSE WILL SLIDE THROUGH THE NORTHERN
PLAINS LATE TODAY INTO TONIGHT. THIS FEATURE WITH AN ASSOCIATED
STRONG JET STREAK WILL FORCE A PERIOD OF LIGHT SNOW OVER THE AREA
TONIGHT. IN ADDITION...A DEVELOPING SURFACE LOW WILL SKIRT SOUTH
CENTRAL SOUTH DAKOTA...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-3 INCH
RANGE...HIGHEST ACROSS THE NORTHERN BLACK HILLS AND ACROSS TRIPP
COUNTY.

SUNDAY...UPPER SHORTWAVE SHIFTS QUICKLY EAST...WITH SOME LIGHT
SNOW POSSIBLY LINGERING ACROSS THE NORTHERN BLACK HILLS AND FAR
SOUTH CENTRAL SOUTH DAKOTA DURING THE MORNING. WEAK UPPER RIDGE
BUILDS ACROSS THE ROCKIES WITH SKIES BECOMING MOSTLY SUNNY LATE
IN THE DAY. ARCTIC HIGH REMAINS ACROSS THE AREA WITH HIGH
TEMPERATURES ONLY IN THE TEENS ACROSS THE SOUTH DAKOTA
PLAINS...AND IN THE 20S ACROSS NORTHEAST WYOMING. LOWS SUNDAY
NIGHT WILL FALL INTO THE 5 TO 20 DEGREE RANGE.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 349 AM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD...BECOMING MORE ZONAL TOWARD THE END OF
THE WEEK. A RELATIVELY WEAK SHORTWAVE WILL BRING A SLIGHT CHANCE
OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY. A
BETTER DEFINED UPPER TROUGH WILL AFFECT THE AREA ON TUESDAY NIGHT
AS A COLD FRONT MOVES THROUGH AT THE SURFACE...BRINGING A CHANCE
OF SNOW TO THE AREA. AT THIS TIME IT LOOKS LIKE THE BEST AREA FOR
MEASURABLE SNOW ACCUMULATION WOULD BE OVER PARTS OF NORTHEASTERN
WYOMING AND SOUTHWESTERN SOUTH DAKOTA. DRY WEATHER IS THEN
EXPECTED THROUGH THE REST OF THE WEEK.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...THEN BECOMING COLDER THAN AVERAGE BEHIND THE
COLD FRONT ON WEDNESDAY. THE BOUNDARY WILL THEN SHIFT NORTHEASTWARD
AGAIN WITH MUCH WARMER THAN AVERAGE TEMPERATURES EXPECTED ON FRIDAY.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 956 AM MST SAT JAN 31 2015

LOW STRATUS/FOG OVER MUCH OF WESTERN SD WILL CREATE IFR/MVFR
CIGS/VSBY THROUGHOUT THE DAY. LIGHT SNOW WILL SPREAD ACROSS THE
AREA LATE THIS AFTERNOON THROUGH TONIGHT...RESULTING IN WIDESPREAD
IFR CONDITIONS. CIGS/VSBY WILL IMPROVE SUNDAY MORNING AS SNOW
TRANSITIONS EASTWARD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST
     SUNDAY FOR SDZ049.

WY...NONE.
&&

$$

UPDATE...JC
SHORT TERM...15
LONG TERM...10
AVIATION...POJORLIE






000
FXUS63 KUNR 311658
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
958 AM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 823 AM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS THIS
MORNING. PHASING NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL
SUPPORT CYCLOGENESIS ACROSS THE CENTRAL PLAINS THIS
AFTERNOON...WITH A DEVELOPING DEFORMATION ZONE NW OF THE LOW. THIS
DEFORMATION ZONE IS PROGGED TO AFFECT SOUTH CENTRAL SD LATE THIS
AFTERNOON INTO TONIGHT. ABUNDANT MOISTURE WILL AVAILABLE WITH THIS
SYSTEM SUPPORTING A PERIOD OF DECENT SNOWS AS LIFT EXPANDS ACROSS
THE REGION TONIGHT. CURRENT EXPECTATION IS FOR 3-4 INCHES ACROSS
MUCH OF TRIPP COUNTY...WITH LOCALLY HIGHER AMOUNTS POSSIBLE ACROSS
THE SOUTHEAST PORTION OF THE COUNTY. HAVE ISSUED A WW ADV FOR
THIS.

&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 349 AM MST SAT JAN 31 2015

UPPER LEVEL ANALYSIS HAS UPPER LOW ACROSS THE SOUTHWEST CONUS WITH
NORTHWEST FLOW ACROSS THE NORTHERN CONUS. SKIES ARE CLOUDY ACROSS
THE NORTHERN PLAINS WITH LOW STRATUS DECK SLIDING SOUTH ACROSS THE
DAKOTAS. AT THE SURFACE...BACK-DOOR COLD FRONT IS CURRENTLY
DROPPING SOUTH ACROSS SOUTH DAKOTA...WITH WINDS TURNING NORTHEAST
BEHIND THE FRONT. TEMPERATURES ARE MAINLY IN THE 20S.

TODAY...UPPER RIDGE SHIFTS SOUTHEAST AS CUT-OFF LOW DEVELOPS
ACROSS THE SOUTHWEST CONUS. SURFACE COLD FRONT AND STRATUS DECK
WILL CONTINUE TO DROP SOUTHWEST ACROSS THE WESTERN SOUTH DAKOTA
PLAINS. COOLER AIR WILL FILTER INTO THE AREA BEHIND THE
FRONT...AND ALONG WITH THE CLOUD COVER...AREAS ACROSS THE SOUTH
DAKOTA PLAINS WILL REMAIN IN THE 20S FOR TODAY. FURTHER WEST IN
WYOMING...HIGH TEMPERATURES WILL BE MILDER...IN THE LOWER 40S.
STRONG NORTHERN STREAM IMPULSE WILL SLIDE THROUGH THE NORTHERN
PLAINS LATE TODAY INTO TONIGHT. THIS FEATURE WITH AN ASSOCIATED
STRONG JET STREAK WILL FORCE A PERIOD OF LIGHT SNOW OVER THE AREA
TONIGHT. IN ADDITION...A DEVELOPING SURFACE LOW WILL SKIRT SOUTH
CENTRAL SOUTH DAKOTA...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-3 INCH
RANGE...HIGHEST ACROSS THE NORTHERN BLACK HILLS AND ACROSS TRIPP
COUNTY.

SUNDAY...UPPER SHORTWAVE SHIFTS QUICKLY EAST...WITH SOME LIGHT
SNOW POSSIBLY LINGERING ACROSS THE NORTHERN BLACK HILLS AND FAR
SOUTH CENTRAL SOUTH DAKOTA DURING THE MORNING. WEAK UPPER RIDGE
BUILDS ACROSS THE ROCKIES WITH SKIES BECOMING MOSTLY SUNNY LATE
IN THE DAY. ARCTIC HIGH REMAINS ACROSS THE AREA WITH HIGH
TEMPERATURES ONLY IN THE TEENS ACROSS THE SOUTH DAKOTA
PLAINS...AND IN THE 20S ACROSS NORTHEAST WYOMING. LOWS SUNDAY
NIGHT WILL FALL INTO THE 5 TO 20 DEGREE RANGE.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 349 AM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD...BECOMING MORE ZONAL TOWARD THE END OF
THE WEEK. A RELATIVELY WEAK SHORTWAVE WILL BRING A SLIGHT CHANCE
OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY. A
BETTER DEFINED UPPER TROUGH WILL AFFECT THE AREA ON TUESDAY NIGHT
AS A COLD FRONT MOVES THROUGH AT THE SURFACE...BRINGING A CHANCE
OF SNOW TO THE AREA. AT THIS TIME IT LOOKS LIKE THE BEST AREA FOR
MEASURABLE SNOW ACCUMULATION WOULD BE OVER PARTS OF NORTHEASTERN
WYOMING AND SOUTHWESTERN SOUTH DAKOTA. DRY WEATHER IS THEN
EXPECTED THROUGH THE REST OF THE WEEK.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...THEN BECOMING COLDER THAN AVERAGE BEHIND THE
COLD FRONT ON WEDNESDAY. THE BOUNDARY WILL THEN SHIFT NORTHEASTWARD
AGAIN WITH MUCH WARMER THAN AVERAGE TEMPERATURES EXPECTED ON FRIDAY.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 956 AM MST SAT JAN 31 2015

LOW STRATUS/FOG OVER MUCH OF WESTERN SD WILL CREATE IFR/MVFR
CIGS/VSBY THROUGHOUT THE DAY. LIGHT SNOW WILL SPREAD ACROSS THE
AREA LATE THIS AFTERNOON THROUGH TONIGHT...RESULTING IN WIDESPREAD
IFR CONDITIONS. CIGS/VSBY WILL IMPROVE SUNDAY MORNING AS SNOW
TRANSITIONS EASTWARD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST
     SUNDAY FOR SDZ049.

WY...NONE.
&&

$$

UPDATE...JC
SHORT TERM...15
LONG TERM...10
AVIATION...POJORLIE






000
FXUS63 KUNR 311658
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
958 AM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 823 AM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID CONUS THIS
MORNING. PHASING NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL
SUPPORT CYCLOGENESIS ACROSS THE CENTRAL PLAINS THIS
AFTERNOON...WITH A DEVELOPING DEFORMATION ZONE NW OF THE LOW. THIS
DEFORMATION ZONE IS PROGGED TO AFFECT SOUTH CENTRAL SD LATE THIS
AFTERNOON INTO TONIGHT. ABUNDANT MOISTURE WILL AVAILABLE WITH THIS
SYSTEM SUPPORTING A PERIOD OF DECENT SNOWS AS LIFT EXPANDS ACROSS
THE REGION TONIGHT. CURRENT EXPECTATION IS FOR 3-4 INCHES ACROSS
MUCH OF TRIPP COUNTY...WITH LOCALLY HIGHER AMOUNTS POSSIBLE ACROSS
THE SOUTHEAST PORTION OF THE COUNTY. HAVE ISSUED A WW ADV FOR
THIS.

&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 349 AM MST SAT JAN 31 2015

UPPER LEVEL ANALYSIS HAS UPPER LOW ACROSS THE SOUTHWEST CONUS WITH
NORTHWEST FLOW ACROSS THE NORTHERN CONUS. SKIES ARE CLOUDY ACROSS
THE NORTHERN PLAINS WITH LOW STRATUS DECK SLIDING SOUTH ACROSS THE
DAKOTAS. AT THE SURFACE...BACK-DOOR COLD FRONT IS CURRENTLY
DROPPING SOUTH ACROSS SOUTH DAKOTA...WITH WINDS TURNING NORTHEAST
BEHIND THE FRONT. TEMPERATURES ARE MAINLY IN THE 20S.

TODAY...UPPER RIDGE SHIFTS SOUTHEAST AS CUT-OFF LOW DEVELOPS
ACROSS THE SOUTHWEST CONUS. SURFACE COLD FRONT AND STRATUS DECK
WILL CONTINUE TO DROP SOUTHWEST ACROSS THE WESTERN SOUTH DAKOTA
PLAINS. COOLER AIR WILL FILTER INTO THE AREA BEHIND THE
FRONT...AND ALONG WITH THE CLOUD COVER...AREAS ACROSS THE SOUTH
DAKOTA PLAINS WILL REMAIN IN THE 20S FOR TODAY. FURTHER WEST IN
WYOMING...HIGH TEMPERATURES WILL BE MILDER...IN THE LOWER 40S.
STRONG NORTHERN STREAM IMPULSE WILL SLIDE THROUGH THE NORTHERN
PLAINS LATE TODAY INTO TONIGHT. THIS FEATURE WITH AN ASSOCIATED
STRONG JET STREAK WILL FORCE A PERIOD OF LIGHT SNOW OVER THE AREA
TONIGHT. IN ADDITION...A DEVELOPING SURFACE LOW WILL SKIRT SOUTH
CENTRAL SOUTH DAKOTA...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-3 INCH
RANGE...HIGHEST ACROSS THE NORTHERN BLACK HILLS AND ACROSS TRIPP
COUNTY.

SUNDAY...UPPER SHORTWAVE SHIFTS QUICKLY EAST...WITH SOME LIGHT
SNOW POSSIBLY LINGERING ACROSS THE NORTHERN BLACK HILLS AND FAR
SOUTH CENTRAL SOUTH DAKOTA DURING THE MORNING. WEAK UPPER RIDGE
BUILDS ACROSS THE ROCKIES WITH SKIES BECOMING MOSTLY SUNNY LATE
IN THE DAY. ARCTIC HIGH REMAINS ACROSS THE AREA WITH HIGH
TEMPERATURES ONLY IN THE TEENS ACROSS THE SOUTH DAKOTA
PLAINS...AND IN THE 20S ACROSS NORTHEAST WYOMING. LOWS SUNDAY
NIGHT WILL FALL INTO THE 5 TO 20 DEGREE RANGE.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 349 AM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD...BECOMING MORE ZONAL TOWARD THE END OF
THE WEEK. A RELATIVELY WEAK SHORTWAVE WILL BRING A SLIGHT CHANCE
OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY. A
BETTER DEFINED UPPER TROUGH WILL AFFECT THE AREA ON TUESDAY NIGHT
AS A COLD FRONT MOVES THROUGH AT THE SURFACE...BRINGING A CHANCE
OF SNOW TO THE AREA. AT THIS TIME IT LOOKS LIKE THE BEST AREA FOR
MEASURABLE SNOW ACCUMULATION WOULD BE OVER PARTS OF NORTHEASTERN
WYOMING AND SOUTHWESTERN SOUTH DAKOTA. DRY WEATHER IS THEN
EXPECTED THROUGH THE REST OF THE WEEK.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...THEN BECOMING COLDER THAN AVERAGE BEHIND THE
COLD FRONT ON WEDNESDAY. THE BOUNDARY WILL THEN SHIFT NORTHEASTWARD
AGAIN WITH MUCH WARMER THAN AVERAGE TEMPERATURES EXPECTED ON FRIDAY.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SUNDAY
ISSUED AT 956 AM MST SAT JAN 31 2015

LOW STRATUS/FOG OVER MUCH OF WESTERN SD WILL CREATE IFR/MVFR
CIGS/VSBY THROUGHOUT THE DAY. LIGHT SNOW WILL SPREAD ACROSS THE
AREA LATE THIS AFTERNOON THROUGH TONIGHT...RESULTING IN WIDESPREAD
IFR CONDITIONS. CIGS/VSBY WILL IMPROVE SUNDAY MORNING AS SNOW
TRANSITIONS EASTWARD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST
     SUNDAY FOR SDZ049.

WY...NONE.
&&

$$

UPDATE...JC
SHORT TERM...15
LONG TERM...10
AVIATION...POJORLIE






000
FXUS63 KUNR 311556
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
856 AM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 823 AM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID COUNS THIS
MORNING. PHASING NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL
SUPPORT CYCLOGENESIS ACROSS THE CENTRAL PLAINS THIS
AFTERNOON...WITH A DEVELOPING DEFORMATION ZONE NW OF THE LOW. THIS
DEFORMATION ZONE IS PROGGED TO AFFECT SOUTH CENTRAL SD LATE THIS
AFTERNOON INTO TONIGHT. ABUNDANT MOISTURE WILL AVAILABLE WITH THIS
SYSTEM SUPPORTING A PERIOD OF DECENT SNOWS AS LIFT EXPANDS ACROSS
THE REGION TONIGHT. CURRENT EXPECTATION IS FOR 3-4 INCHES ACROSS
MUCH OF TRIPP COUNTY...WITH LOCALLY HIGHER AMOUNTS POSSIBLE ACROSS
THE SOUTHEAST PORTION OF THE COUNTY. HAVE ISSUED A WW ADV FOR
THIS.

&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 349 AM MST SAT JAN 31 2015

UPPER LEVEL ANALYSIS HAS UPPER LOW ACROSS THE SOUTHWEST CONUS WITH
NORTHWEST FLOW ACROSS THE NORTHERN CONUS. SKIES ARE CLOUDY ACROSS
THE NORTHERN PLAINS WITH LOW STRATUS DECK SLIDING SOUTH ACROSS THE
DAKOTAS. AT THE SURFACE...BACK-DOOR COLD FRONT IS CURRENTLY
DROPPING SOUTH ACROSS SOUTH DAKOTA...WITH WINDS TURNING NORTHEAST
BEHIND THE FRONT. TEMPERATURES ARE MAINLY IN THE 20S.

TODAY...UPPER RIDGE SHIFTS SOUTHEAST AS CUT-OFF LOW DEVELOPS
ACROSS THE SOUTHWEST CONUS. SURFACE COLD FRONT AND STRATUS DECK
WILL CONTINUE TO DROP SOUTHWEST ACROSS THE WESTERN SOUTH DAKOTA
PLAINS. COOLER AIR WILL FILTER INTO THE AREA BEHIND THE
FRONT...AND ALONG WITH THE CLOUD COVER...AREAS ACROSS THE SOUTH
DAKOTA PLAINS WILL REMAIN IN THE 20S FOR TODAY. FURTHER WEST IN
WYOMING...HIGH TEMPERATURES WILL BE MILDER...IN THE LOWER 40S.
STRONG NORTHERN STREAM IMPULSE WILL SLIDE THROUGH THE NORTHERN
PLAINS LATE TODAY INTO TONIGHT. THIS FEATURE WITH AN ASSOCIATED
STRONG JET STREAK WILL FORCE A PERIOD OF LIGHT SNOW OVER THE AREA
TONIGHT. IN ADDITION...A DEVELOPING SURFACE LOW WILL SKIRT SOUTH
CENTRAL SOUTH DAKOTA...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-3 INCH
RANGE...HIGHEST ACROSS THE NORTHERN BLACK HILLS AND ACROSS TRIPP
COUNTY.

SUNDAY...UPPER SHORTWAVE SHIFTS QUICKLY EAST...WITH SOME LIGHT
SNOW POSSIBLY LINGERING ACROSS THE NORTHERN BLACK HILLS AND FAR
SOUTH CENTRAL SOUTH DAKOTA DURING THE MORNING. WEAK UPPER RIDGE
BUILDS ACROSS THE ROCKIES WITH SKIES BECOMING MOSTLY SUNNY LATE
IN THE DAY. ARCTIC HIGH REMAINS ACROSS THE AREA WITH HIGH
TEMPERATURES ONLY IN THE TEENS ACROSS THE SOUTH DAKOTA
PLAINS...AND IN THE 20S ACROSS NORTHEAST WYOMING. LOWS SUNDAY
NIGHT WILL FALL INTO THE 5 TO 20 DEGREE RANGE.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 349 AM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD...BECOMING MORE ZONAL TOWARD THE END OF
THE WEEK. A RELATIVELY WEAK SHORTWAVE WILL BRING A SLIGHT CHANCE
OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY. A
BETTER DEFINED UPPER TROUGH WILL AFFECT THE AREA ON TUESDAY NIGHT
AS A COLD FRONT MOVES THROUGH AT THE SURFACE...BRINGING A CHANCE
OF SNOW TO THE AREA. AT THIS TIME IT LOOKS LIKE THE BEST AREA FOR
MEASURABLE SNOW ACCUMULATION WOULD BE OVER PARTS OF NORTHEASTERN
WYOMING AND SOUTHWESTERN SOUTH DAKOTA. DRY WEATHER IS THEN
EXPECTED THROUGH THE REST OF THE WEEK.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...THEN BECOMING COLDER THAN AVERAGE BEHIND THE
COLD FRONT ON WEDNESDAY. THE BOUNDARY WILL THEN SHIFT NORTHEASTWARD
AGAIN WITH MUCH WARMER THAN AVERAGE TEMPERATURES EXPECTED ON FRIDAY.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING
ISSUED AT 349 AM MST SAT JAN 31 2015

AREA OF IFR/MVFR STRATUS OVER NERN AND NCNTRL SD WILL SINK INTO
WESTERN SOUTH DAKOTA THIS MORNING...REACHING THE BLACK HILLS
AROUND 15Z THEN CONTINUING TO SINK SOUTHWEST THROUGH THIS EVENING.
LIGHT SNOW WILL SPREAD ACROSS MUCH OF THE AREA FROM LATE THIS
AFTERNOON THROUGH TONIGHT...RESULTING IN WIDESPREAD IFR
CONDITIONS.


&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST
     SUNDAY FOR SDZ049.

WY...NONE.
&&

$$

UPDATE...JC
SHORT TERM...15
LONG TERM...10
AVIATION...10






000
FXUS63 KUNR 311556
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
856 AM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 823 AM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID COUNS THIS
MORNING. PHASING NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL
SUPPORT CYCLOGENESIS ACROSS THE CENTRAL PLAINS THIS
AFTERNOON...WITH A DEVELOPING DEFORMATION ZONE NW OF THE LOW. THIS
DEFORMATION ZONE IS PROGGED TO AFFECT SOUTH CENTRAL SD LATE THIS
AFTERNOON INTO TONIGHT. ABUNDANT MOISTURE WILL AVAILABLE WITH THIS
SYSTEM SUPPORTING A PERIOD OF DECENT SNOWS AS LIFT EXPANDS ACROSS
THE REGION TONIGHT. CURRENT EXPECTATION IS FOR 3-4 INCHES ACROSS
MUCH OF TRIPP COUNTY...WITH LOCALLY HIGHER AMOUNTS POSSIBLE ACROSS
THE SOUTHEAST PORTION OF THE COUNTY. HAVE ISSUED A WW ADV FOR
THIS.

&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 349 AM MST SAT JAN 31 2015

UPPER LEVEL ANALYSIS HAS UPPER LOW ACROSS THE SOUTHWEST CONUS WITH
NORTHWEST FLOW ACROSS THE NORTHERN CONUS. SKIES ARE CLOUDY ACROSS
THE NORTHERN PLAINS WITH LOW STRATUS DECK SLIDING SOUTH ACROSS THE
DAKOTAS. AT THE SURFACE...BACK-DOOR COLD FRONT IS CURRENTLY
DROPPING SOUTH ACROSS SOUTH DAKOTA...WITH WINDS TURNING NORTHEAST
BEHIND THE FRONT. TEMPERATURES ARE MAINLY IN THE 20S.

TODAY...UPPER RIDGE SHIFTS SOUTHEAST AS CUT-OFF LOW DEVELOPS
ACROSS THE SOUTHWEST CONUS. SURFACE COLD FRONT AND STRATUS DECK
WILL CONTINUE TO DROP SOUTHWEST ACROSS THE WESTERN SOUTH DAKOTA
PLAINS. COOLER AIR WILL FILTER INTO THE AREA BEHIND THE
FRONT...AND ALONG WITH THE CLOUD COVER...AREAS ACROSS THE SOUTH
DAKOTA PLAINS WILL REMAIN IN THE 20S FOR TODAY. FURTHER WEST IN
WYOMING...HIGH TEMPERATURES WILL BE MILDER...IN THE LOWER 40S.
STRONG NORTHERN STREAM IMPULSE WILL SLIDE THROUGH THE NORTHERN
PLAINS LATE TODAY INTO TONIGHT. THIS FEATURE WITH AN ASSOCIATED
STRONG JET STREAK WILL FORCE A PERIOD OF LIGHT SNOW OVER THE AREA
TONIGHT. IN ADDITION...A DEVELOPING SURFACE LOW WILL SKIRT SOUTH
CENTRAL SOUTH DAKOTA...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-3 INCH
RANGE...HIGHEST ACROSS THE NORTHERN BLACK HILLS AND ACROSS TRIPP
COUNTY.

SUNDAY...UPPER SHORTWAVE SHIFTS QUICKLY EAST...WITH SOME LIGHT
SNOW POSSIBLY LINGERING ACROSS THE NORTHERN BLACK HILLS AND FAR
SOUTH CENTRAL SOUTH DAKOTA DURING THE MORNING. WEAK UPPER RIDGE
BUILDS ACROSS THE ROCKIES WITH SKIES BECOMING MOSTLY SUNNY LATE
IN THE DAY. ARCTIC HIGH REMAINS ACROSS THE AREA WITH HIGH
TEMPERATURES ONLY IN THE TEENS ACROSS THE SOUTH DAKOTA
PLAINS...AND IN THE 20S ACROSS NORTHEAST WYOMING. LOWS SUNDAY
NIGHT WILL FALL INTO THE 5 TO 20 DEGREE RANGE.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 349 AM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD...BECOMING MORE ZONAL TOWARD THE END OF
THE WEEK. A RELATIVELY WEAK SHORTWAVE WILL BRING A SLIGHT CHANCE
OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY. A
BETTER DEFINED UPPER TROUGH WILL AFFECT THE AREA ON TUESDAY NIGHT
AS A COLD FRONT MOVES THROUGH AT THE SURFACE...BRINGING A CHANCE
OF SNOW TO THE AREA. AT THIS TIME IT LOOKS LIKE THE BEST AREA FOR
MEASURABLE SNOW ACCUMULATION WOULD BE OVER PARTS OF NORTHEASTERN
WYOMING AND SOUTHWESTERN SOUTH DAKOTA. DRY WEATHER IS THEN
EXPECTED THROUGH THE REST OF THE WEEK.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...THEN BECOMING COLDER THAN AVERAGE BEHIND THE
COLD FRONT ON WEDNESDAY. THE BOUNDARY WILL THEN SHIFT NORTHEASTWARD
AGAIN WITH MUCH WARMER THAN AVERAGE TEMPERATURES EXPECTED ON FRIDAY.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING
ISSUED AT 349 AM MST SAT JAN 31 2015

AREA OF IFR/MVFR STRATUS OVER NERN AND NCNTRL SD WILL SINK INTO
WESTERN SOUTH DAKOTA THIS MORNING...REACHING THE BLACK HILLS
AROUND 15Z THEN CONTINUING TO SINK SOUTHWEST THROUGH THIS EVENING.
LIGHT SNOW WILL SPREAD ACROSS MUCH OF THE AREA FROM LATE THIS
AFTERNOON THROUGH TONIGHT...RESULTING IN WIDESPREAD IFR
CONDITIONS.


&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST
     SUNDAY FOR SDZ049.

WY...NONE.
&&

$$

UPDATE...JC
SHORT TERM...15
LONG TERM...10
AVIATION...10






000
FXUS63 KUNR 311556
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
856 AM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 823 AM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID COUNS THIS
MORNING. PHASING NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL
SUPPORT CYCLOGENESIS ACROSS THE CENTRAL PLAINS THIS
AFTERNOON...WITH A DEVELOPING DEFORMATION ZONE NW OF THE LOW. THIS
DEFORMATION ZONE IS PROGGED TO AFFECT SOUTH CENTRAL SD LATE THIS
AFTERNOON INTO TONIGHT. ABUNDANT MOISTURE WILL AVAILABLE WITH THIS
SYSTEM SUPPORTING A PERIOD OF DECENT SNOWS AS LIFT EXPANDS ACROSS
THE REGION TONIGHT. CURRENT EXPECTATION IS FOR 3-4 INCHES ACROSS
MUCH OF TRIPP COUNTY...WITH LOCALLY HIGHER AMOUNTS POSSIBLE ACROSS
THE SOUTHEAST PORTION OF THE COUNTY. HAVE ISSUED A WW ADV FOR
THIS.

&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 349 AM MST SAT JAN 31 2015

UPPER LEVEL ANALYSIS HAS UPPER LOW ACROSS THE SOUTHWEST CONUS WITH
NORTHWEST FLOW ACROSS THE NORTHERN CONUS. SKIES ARE CLOUDY ACROSS
THE NORTHERN PLAINS WITH LOW STRATUS DECK SLIDING SOUTH ACROSS THE
DAKOTAS. AT THE SURFACE...BACK-DOOR COLD FRONT IS CURRENTLY
DROPPING SOUTH ACROSS SOUTH DAKOTA...WITH WINDS TURNING NORTHEAST
BEHIND THE FRONT. TEMPERATURES ARE MAINLY IN THE 20S.

TODAY...UPPER RIDGE SHIFTS SOUTHEAST AS CUT-OFF LOW DEVELOPS
ACROSS THE SOUTHWEST CONUS. SURFACE COLD FRONT AND STRATUS DECK
WILL CONTINUE TO DROP SOUTHWEST ACROSS THE WESTERN SOUTH DAKOTA
PLAINS. COOLER AIR WILL FILTER INTO THE AREA BEHIND THE
FRONT...AND ALONG WITH THE CLOUD COVER...AREAS ACROSS THE SOUTH
DAKOTA PLAINS WILL REMAIN IN THE 20S FOR TODAY. FURTHER WEST IN
WYOMING...HIGH TEMPERATURES WILL BE MILDER...IN THE LOWER 40S.
STRONG NORTHERN STREAM IMPULSE WILL SLIDE THROUGH THE NORTHERN
PLAINS LATE TODAY INTO TONIGHT. THIS FEATURE WITH AN ASSOCIATED
STRONG JET STREAK WILL FORCE A PERIOD OF LIGHT SNOW OVER THE AREA
TONIGHT. IN ADDITION...A DEVELOPING SURFACE LOW WILL SKIRT SOUTH
CENTRAL SOUTH DAKOTA...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-3 INCH
RANGE...HIGHEST ACROSS THE NORTHERN BLACK HILLS AND ACROSS TRIPP
COUNTY.

SUNDAY...UPPER SHORTWAVE SHIFTS QUICKLY EAST...WITH SOME LIGHT
SNOW POSSIBLY LINGERING ACROSS THE NORTHERN BLACK HILLS AND FAR
SOUTH CENTRAL SOUTH DAKOTA DURING THE MORNING. WEAK UPPER RIDGE
BUILDS ACROSS THE ROCKIES WITH SKIES BECOMING MOSTLY SUNNY LATE
IN THE DAY. ARCTIC HIGH REMAINS ACROSS THE AREA WITH HIGH
TEMPERATURES ONLY IN THE TEENS ACROSS THE SOUTH DAKOTA
PLAINS...AND IN THE 20S ACROSS NORTHEAST WYOMING. LOWS SUNDAY
NIGHT WILL FALL INTO THE 5 TO 20 DEGREE RANGE.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 349 AM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD...BECOMING MORE ZONAL TOWARD THE END OF
THE WEEK. A RELATIVELY WEAK SHORTWAVE WILL BRING A SLIGHT CHANCE
OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY. A
BETTER DEFINED UPPER TROUGH WILL AFFECT THE AREA ON TUESDAY NIGHT
AS A COLD FRONT MOVES THROUGH AT THE SURFACE...BRINGING A CHANCE
OF SNOW TO THE AREA. AT THIS TIME IT LOOKS LIKE THE BEST AREA FOR
MEASURABLE SNOW ACCUMULATION WOULD BE OVER PARTS OF NORTHEASTERN
WYOMING AND SOUTHWESTERN SOUTH DAKOTA. DRY WEATHER IS THEN
EXPECTED THROUGH THE REST OF THE WEEK.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...THEN BECOMING COLDER THAN AVERAGE BEHIND THE
COLD FRONT ON WEDNESDAY. THE BOUNDARY WILL THEN SHIFT NORTHEASTWARD
AGAIN WITH MUCH WARMER THAN AVERAGE TEMPERATURES EXPECTED ON FRIDAY.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING
ISSUED AT 349 AM MST SAT JAN 31 2015

AREA OF IFR/MVFR STRATUS OVER NERN AND NCNTRL SD WILL SINK INTO
WESTERN SOUTH DAKOTA THIS MORNING...REACHING THE BLACK HILLS
AROUND 15Z THEN CONTINUING TO SINK SOUTHWEST THROUGH THIS EVENING.
LIGHT SNOW WILL SPREAD ACROSS MUCH OF THE AREA FROM LATE THIS
AFTERNOON THROUGH TONIGHT...RESULTING IN WIDESPREAD IFR
CONDITIONS.


&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST
     SUNDAY FOR SDZ049.

WY...NONE.
&&

$$

UPDATE...JC
SHORT TERM...15
LONG TERM...10
AVIATION...10






000
FXUS63 KUNR 311556
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
856 AM MST SAT JAN 31 2015

.UPDATE...
ISSUED AT 823 AM MST SAT JAN 31 2015

POTENT WINTER STORM TAKING SHAPE ACROSS THE MID COUNS THIS
MORNING. PHASING NORTHERN AND SOUTHERN STREAM UPPER TROUGHS WILL
SUPPORT CYCLOGENESIS ACROSS THE CENTRAL PLAINS THIS
AFTERNOON...WITH A DEVELOPING DEFORMATION ZONE NW OF THE LOW. THIS
DEFORMATION ZONE IS PROGGED TO AFFECT SOUTH CENTRAL SD LATE THIS
AFTERNOON INTO TONIGHT. ABUNDANT MOISTURE WILL AVAILABLE WITH THIS
SYSTEM SUPPORTING A PERIOD OF DECENT SNOWS AS LIFT EXPANDS ACROSS
THE REGION TONIGHT. CURRENT EXPECTATION IS FOR 3-4 INCHES ACROSS
MUCH OF TRIPP COUNTY...WITH LOCALLY HIGHER AMOUNTS POSSIBLE ACROSS
THE SOUTHEAST PORTION OF THE COUNTY. HAVE ISSUED A WW ADV FOR
THIS.

&&

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 349 AM MST SAT JAN 31 2015

UPPER LEVEL ANALYSIS HAS UPPER LOW ACROSS THE SOUTHWEST CONUS WITH
NORTHWEST FLOW ACROSS THE NORTHERN CONUS. SKIES ARE CLOUDY ACROSS
THE NORTHERN PLAINS WITH LOW STRATUS DECK SLIDING SOUTH ACROSS THE
DAKOTAS. AT THE SURFACE...BACK-DOOR COLD FRONT IS CURRENTLY
DROPPING SOUTH ACROSS SOUTH DAKOTA...WITH WINDS TURNING NORTHEAST
BEHIND THE FRONT. TEMPERATURES ARE MAINLY IN THE 20S.

TODAY...UPPER RIDGE SHIFTS SOUTHEAST AS CUT-OFF LOW DEVELOPS
ACROSS THE SOUTHWEST CONUS. SURFACE COLD FRONT AND STRATUS DECK
WILL CONTINUE TO DROP SOUTHWEST ACROSS THE WESTERN SOUTH DAKOTA
PLAINS. COOLER AIR WILL FILTER INTO THE AREA BEHIND THE
FRONT...AND ALONG WITH THE CLOUD COVER...AREAS ACROSS THE SOUTH
DAKOTA PLAINS WILL REMAIN IN THE 20S FOR TODAY. FURTHER WEST IN
WYOMING...HIGH TEMPERATURES WILL BE MILDER...IN THE LOWER 40S.
STRONG NORTHERN STREAM IMPULSE WILL SLIDE THROUGH THE NORTHERN
PLAINS LATE TODAY INTO TONIGHT. THIS FEATURE WITH AN ASSOCIATED
STRONG JET STREAK WILL FORCE A PERIOD OF LIGHT SNOW OVER THE AREA
TONIGHT. IN ADDITION...A DEVELOPING SURFACE LOW WILL SKIRT SOUTH
CENTRAL SOUTH DAKOTA...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-3 INCH
RANGE...HIGHEST ACROSS THE NORTHERN BLACK HILLS AND ACROSS TRIPP
COUNTY.

SUNDAY...UPPER SHORTWAVE SHIFTS QUICKLY EAST...WITH SOME LIGHT
SNOW POSSIBLY LINGERING ACROSS THE NORTHERN BLACK HILLS AND FAR
SOUTH CENTRAL SOUTH DAKOTA DURING THE MORNING. WEAK UPPER RIDGE
BUILDS ACROSS THE ROCKIES WITH SKIES BECOMING MOSTLY SUNNY LATE
IN THE DAY. ARCTIC HIGH REMAINS ACROSS THE AREA WITH HIGH
TEMPERATURES ONLY IN THE TEENS ACROSS THE SOUTH DAKOTA
PLAINS...AND IN THE 20S ACROSS NORTHEAST WYOMING. LOWS SUNDAY
NIGHT WILL FALL INTO THE 5 TO 20 DEGREE RANGE.

.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 349 AM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD...BECOMING MORE ZONAL TOWARD THE END OF
THE WEEK. A RELATIVELY WEAK SHORTWAVE WILL BRING A SLIGHT CHANCE
OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY. A
BETTER DEFINED UPPER TROUGH WILL AFFECT THE AREA ON TUESDAY NIGHT
AS A COLD FRONT MOVES THROUGH AT THE SURFACE...BRINGING A CHANCE
OF SNOW TO THE AREA. AT THIS TIME IT LOOKS LIKE THE BEST AREA FOR
MEASURABLE SNOW ACCUMULATION WOULD BE OVER PARTS OF NORTHEASTERN
WYOMING AND SOUTHWESTERN SOUTH DAKOTA. DRY WEATHER IS THEN
EXPECTED THROUGH THE REST OF THE WEEK.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...THEN BECOMING COLDER THAN AVERAGE BEHIND THE
COLD FRONT ON WEDNESDAY. THE BOUNDARY WILL THEN SHIFT NORTHEASTWARD
AGAIN WITH MUCH WARMER THAN AVERAGE TEMPERATURES EXPECTED ON FRIDAY.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING
ISSUED AT 349 AM MST SAT JAN 31 2015

AREA OF IFR/MVFR STRATUS OVER NERN AND NCNTRL SD WILL SINK INTO
WESTERN SOUTH DAKOTA THIS MORNING...REACHING THE BLACK HILLS
AROUND 15Z THEN CONTINUING TO SINK SOUTHWEST THROUGH THIS EVENING.
LIGHT SNOW WILL SPREAD ACROSS MUCH OF THE AREA FROM LATE THIS
AFTERNOON THROUGH TONIGHT...RESULTING IN WIDESPREAD IFR
CONDITIONS.


&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 6 AM CST
     SUNDAY FOR SDZ049.

WY...NONE.
&&

$$

UPDATE...JC
SHORT TERM...15
LONG TERM...10
AVIATION...10






000
FXUS65 KCYS 311230
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
530 AM MST SAT JAN 31 2015

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 530 AM MST SAT JAN 31 2015

MADE A FEW CHANGES TO THE FORECAST FOR TODAY AS CURRENT WATER
VAPOR IMAGERY TRENDS SUGGEST ENERGY ASSOCIATED WITH THE SOUTHERN
STORM SYSTEM LOOKS TO LINGER OVER THE FORECAST AREA SLIGHTLY
LONGER THAN PREVIOUS THINKING. THE MIDLEVEL BAROCLINIC BAND ON
THE NORTHERN FRINGE OF THE UPPER LOW OVER THE DESERT SOUTHWEST IS
PROGGED TO REMAIN OVERHEAD THROUGH MIDDAY TODAY...WITH A SURFACE
TROUGH POSITIONED JUST SOUTHEAST OF THE FORECAST AREA EXTENDING
FROM CENTRAL COLORADO UP THRU CENTRAL NEBRASKA. SFC CYCLOGENESIS
OCCURRING OVER COLORADO TODAY WITHIN THIS TROUGH WILL PULL THE
MAIN COLD FRONT CURRENTLY OVER THE NORTHERN PLAINS SOUTH THRU THE
FORECAST AREA. SOUTHEASTERLY FLOW AT 700 MB OVER THE PLAINS AHEAD
OF THE MIDLEVEL FRONT WILL ADVECT IN SOME MOISTURE THIS MORNING
WITH WEAK ISENTROPIC LIFT DEVELOPING THROUGH THE DAY OVER THE
PANHANDLE AS THE SFC FRONT STEADILY SHIFTS SOUTH. THE MAIN PRECIP
BAND LOOKS TO DEVELOP OVER THE SOUTHERN PANHANDLE THIS MORNING
WITHIN THE AREA OF ISENTROPIC LIFT...AND THEN SHIFTS NORTH A BIT
INTO THE CENTRAL PANHANDLE THIS AFTERNOON BEFORE THE NORTHERN
STREAM SHORTWAVE FINALLY NUDGES THE MIDLEVEL FRONT AND ASSOCIATED
PRECIP BAND EAST EARLY THIS EVENING. SO BUMPED UP POPS AND SNOW
TOTALS ESPECIALLY ACROSS BOX BUTTE AND MORRILL COUNTIES WITHIN
MAIN AREA OF MIDLEVEL CONVERGENCE AND LIFT WHERE AROUND AN INCH OF
SNOW IS LIKELY THIS AFTERNOON. MODELS ALSO SHOW SOME WEAK
INSTABILITY IN THIS AREA AS WELL WHICH WILL AID IN OVERALL SHOWER
CHANCES. DO THINK PRECIP TYPE WILL BE MAJORITY SNOW BASED ON
TIMING OF THE SFC FRONT THIS MORNING...AND FORECAST SOUNDINGS
DEPICTING THE MAJORITY OF THE COLUMN WILL BE BELOW FREEZING.
CANNOT RULE OUT A MIX OF RAIN-SNOW AT THE ONSET OF PRECIP THO.
STILL EXPECTING SNOW SHOWERS TO CONTINUE IN THE SNOWY AND SIERRA
MADRES THIS MORNING AHEAD OF A SHORTWAVE MOVING UP FROM UTAH INTO
WESTERN CO.

THE NORTHERN STREAM SHORTWAVE TROUGH WILL SLIDE SOUTHEAST OVER THE
FORECAST AREA THIS EVENING WITH SHOWERS REDEVELOPING OVER MUCH OF
THE CWA THROUGH THE EVENING AND OVERNIGHT PERIOD. EXPECTING A
QUICK BURST OF SNOW WITH ANY SHOWER THAT OCCURS WITH ACCUMULATIONS
LOOKING TO GENERALLY BE ONE HALF INCH OR LESS IN THE LOWER
ELEVATIONS...AND AN INCH OR TWO IN THE MOUNTAINS. THE WAVE WILL
DEPART THE AREA QUICKLY SUNDAY MORNING WITH DRY AND COOLER
CONDITIONS ANTICIPATED FOR THE REST OF SUNDAY. HIGH PRESSURE WILL
BUILD OVER THE ROCKIES SUNDAY NIGHT WITH A WEAK DISTURBANCE MOVING
ATOP THE RIDGE AND OVER THE ROCKIES THROUGH THIS TIME. THE LEESIDE
PRESSURE TROUGH WILL DEEPEN QUITE RAPIDLY AHEAD OF THIS WAVE WITH
THE LLVL PRESSURE GRADIENT STRENGTHENING AS A RESULT. BY 06Z
MONDAY...THE CAG-CPR GRADIENT WILL BE ROUGHLY 55-60 DAM WITH WINDS
IN THE 750 TO 700 MB LAYER PROGGED TO BE IN EXCESS OF 50 KTS
THROUGH 12Z. A CROSS-SECTION PLOT THROUGH THE WIND PRONE AREAS
SHOW THE INVERSION SETTING UP JUST AROUND MOUNTAIN TOP LEVEL AND
WITHIN THE BAND OF STRONGER WINDS. SO...LOOKING AT PERHAPS A
MARGINAL HIGH WIND EVENT LATE SUNDAY NIGHT THROUGH MONDAY MORNING.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 530 AM MST SAT JAN 31 2015

THE EARLY PART OF NEXT WEEK WILL FEATURE WINDY CONDITIONS ACROSS
SOUTHEAST WYOMING AND INTERMITTENT SNOWS...MAINLY ACROSS THE MTNS.
THE LLVL CAG-CPR GRADIENT WILL BECOME HIGH ENOUGH (AROUND 60 METERS)
BY MON MORNING TO SUGGEST A MARGINAL HIGH WIND EVENT ACROSS THE WIND
PRONE AREAS.  HOWEVER...THE BETTER CHANCE OF HIGH WINDS WILL BE LATE
MON NIGHT INTO TUES AS THE LLVL GRADIENT INCREASES FURTHER TO 75-80
METERS AND FLOW ALOFT IS STRONGER.  THERE IS EVEN THE POTENTIAL FOR
HIGH WINDS TO SPREAD ONTO THE ADJACENT PLAINS OF SOUTHEAST WYOMING.
THE GRADIENT BEGINS TO DECREASE BY LATE TUES AS HIGHER PRESSURES AND
A COLD FRONT BACK INTO THE REGION.  TEMPS ON MON AND TUES WILL BE
ABOVE NORMAL WITH DOWNSLOPING WESTERLY WINDS PREVAILING.

THE OTHER STORY EARLY NEXT WEEK WILL BE THE OROGRAPHIC SNOWFALL
ACROSS THE SIERRA MADRE AND SNOWY RANGES.  MOIST NORTHWESTERLY FLOW
WILL TRANSPORT A GOOD AMOUNT OF PACIFIC MOISTURE INTO WYOMING.  BOTH
THE GFS AND ECMWF INDICATE A GOOD CHANCE OF SNOW THROUGH MIDDAY MON
AND THEN A BRIEF BREAK BEFORE MORE SNOW ARRIVES ON TUES AFTN.  SNOW
AMOUNTS (COMBINED WITH THE WINDY CONDITIONS) COULD WARRANT SOME SORT
OF WINTER WEATHER HEADLINE AT THAT TIME.  BY WED MORNING SNOW COULD
SPREAD ONTO THE PLAINS IN THE LLVL UPSLOPE BEHIND THE FRONT COMBINED
WITH SOME UPPER LEVEL SUPPORT. GENERALLY HAVE SLIGHT CHANCE POPS FOR
NOW ALONG WITH COOLER TEMPS.  IT IS A RATHER PROGRESSIVE PATTERN SO
INCREASING HEIGHTS AND TEMPS WILL OCCUR BY THURS AND FRI.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 530 AM MST SAT JAN 31 2015

MAINLY VFR CONDITIONS THROUGH THE EARLY AFTERNOON.  VFR CIGS WITH
BASES 5-10 THOUSAND FEET WILL BE COMMON THROUGH MIDDAY.  CIGS WILL
LOWER OVER MUCH OF THE REGION BY LATE THIS AFTERNOON AND AFTER 00Z
AS A COLD FRONT PUSHES ACROSS THE AREA.  LIGHT SNOW AND BRIEF IFR
VIS WILL BE POSSIBLE OVER PORTIONS OF THE NEBRASKA PANHANDLE.  WINDS
BEHIND THE FRONT WILL OCCASIONALLY GUST TO 25 KTS OVER THE PLAINS.

&&

.FIRE WEATHER...
ISSUED AT 530 AM MST SAT JAN 31 2015

SNOW SHOWERS WILL PERSIST OVER THE SNOWY AND SIERRA MADRE
MOUNTAINS THROUGH MUCH OF TODAY...WHILE RAIN AND SNOW SHOWERS WILL
DEVELOP OVER THE PLAINS AND HIGH VALLEYS THIS AFTERNOON AND EVENING.
SNOW ACCUMULATIONS WILL REMAIN GENERALLY LIGHT. SUNDAY WILL
REMAIN COOL AND MOSTLY DRY WITH WINDY CONDITIONS RETURNING TO THE
WIND PRONE AREAS OF SOUTHEAST WYOMING LATE SUNDAY NIGHT. WARM AND
WINDY CONDITIONS WILL CONTINUE FOR THE DISTRICT THROUGH MIDWEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...RJM




000
FXUS65 KCYS 311230
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
530 AM MST SAT JAN 31 2015

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 530 AM MST SAT JAN 31 2015

MADE A FEW CHANGES TO THE FORECAST FOR TODAY AS CURRENT WATER
VAPOR IMAGERY TRENDS SUGGEST ENERGY ASSOCIATED WITH THE SOUTHERN
STORM SYSTEM LOOKS TO LINGER OVER THE FORECAST AREA SLIGHTLY
LONGER THAN PREVIOUS THINKING. THE MIDLEVEL BAROCLINIC BAND ON
THE NORTHERN FRINGE OF THE UPPER LOW OVER THE DESERT SOUTHWEST IS
PROGGED TO REMAIN OVERHEAD THROUGH MIDDAY TODAY...WITH A SURFACE
TROUGH POSITIONED JUST SOUTHEAST OF THE FORECAST AREA EXTENDING
FROM CENTRAL COLORADO UP THRU CENTRAL NEBRASKA. SFC CYCLOGENESIS
OCCURRING OVER COLORADO TODAY WITHIN THIS TROUGH WILL PULL THE
MAIN COLD FRONT CURRENTLY OVER THE NORTHERN PLAINS SOUTH THRU THE
FORECAST AREA. SOUTHEASTERLY FLOW AT 700 MB OVER THE PLAINS AHEAD
OF THE MIDLEVEL FRONT WILL ADVECT IN SOME MOISTURE THIS MORNING
WITH WEAK ISENTROPIC LIFT DEVELOPING THROUGH THE DAY OVER THE
PANHANDLE AS THE SFC FRONT STEADILY SHIFTS SOUTH. THE MAIN PRECIP
BAND LOOKS TO DEVELOP OVER THE SOUTHERN PANHANDLE THIS MORNING
WITHIN THE AREA OF ISENTROPIC LIFT...AND THEN SHIFTS NORTH A BIT
INTO THE CENTRAL PANHANDLE THIS AFTERNOON BEFORE THE NORTHERN
STREAM SHORTWAVE FINALLY NUDGES THE MIDLEVEL FRONT AND ASSOCIATED
PRECIP BAND EAST EARLY THIS EVENING. SO BUMPED UP POPS AND SNOW
TOTALS ESPECIALLY ACROSS BOX BUTTE AND MORRILL COUNTIES WITHIN
MAIN AREA OF MIDLEVEL CONVERGENCE AND LIFT WHERE AROUND AN INCH OF
SNOW IS LIKELY THIS AFTERNOON. MODELS ALSO SHOW SOME WEAK
INSTABILITY IN THIS AREA AS WELL WHICH WILL AID IN OVERALL SHOWER
CHANCES. DO THINK PRECIP TYPE WILL BE MAJORITY SNOW BASED ON
TIMING OF THE SFC FRONT THIS MORNING...AND FORECAST SOUNDINGS
DEPICTING THE MAJORITY OF THE COLUMN WILL BE BELOW FREEZING.
CANNOT RULE OUT A MIX OF RAIN-SNOW AT THE ONSET OF PRECIP THO.
STILL EXPECTING SNOW SHOWERS TO CONTINUE IN THE SNOWY AND SIERRA
MADRES THIS MORNING AHEAD OF A SHORTWAVE MOVING UP FROM UTAH INTO
WESTERN CO.

THE NORTHERN STREAM SHORTWAVE TROUGH WILL SLIDE SOUTHEAST OVER THE
FORECAST AREA THIS EVENING WITH SHOWERS REDEVELOPING OVER MUCH OF
THE CWA THROUGH THE EVENING AND OVERNIGHT PERIOD. EXPECTING A
QUICK BURST OF SNOW WITH ANY SHOWER THAT OCCURS WITH ACCUMULATIONS
LOOKING TO GENERALLY BE ONE HALF INCH OR LESS IN THE LOWER
ELEVATIONS...AND AN INCH OR TWO IN THE MOUNTAINS. THE WAVE WILL
DEPART THE AREA QUICKLY SUNDAY MORNING WITH DRY AND COOLER
CONDITIONS ANTICIPATED FOR THE REST OF SUNDAY. HIGH PRESSURE WILL
BUILD OVER THE ROCKIES SUNDAY NIGHT WITH A WEAK DISTURBANCE MOVING
ATOP THE RIDGE AND OVER THE ROCKIES THROUGH THIS TIME. THE LEESIDE
PRESSURE TROUGH WILL DEEPEN QUITE RAPIDLY AHEAD OF THIS WAVE WITH
THE LLVL PRESSURE GRADIENT STRENGTHENING AS A RESULT. BY 06Z
MONDAY...THE CAG-CPR GRADIENT WILL BE ROUGHLY 55-60 DAM WITH WINDS
IN THE 750 TO 700 MB LAYER PROGGED TO BE IN EXCESS OF 50 KTS
THROUGH 12Z. A CROSS-SECTION PLOT THROUGH THE WIND PRONE AREAS
SHOW THE INVERSION SETTING UP JUST AROUND MOUNTAIN TOP LEVEL AND
WITHIN THE BAND OF STRONGER WINDS. SO...LOOKING AT PERHAPS A
MARGINAL HIGH WIND EVENT LATE SUNDAY NIGHT THROUGH MONDAY MORNING.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 530 AM MST SAT JAN 31 2015

THE EARLY PART OF NEXT WEEK WILL FEATURE WINDY CONDITIONS ACROSS
SOUTHEAST WYOMING AND INTERMITTENT SNOWS...MAINLY ACROSS THE MTNS.
THE LLVL CAG-CPR GRADIENT WILL BECOME HIGH ENOUGH (AROUND 60 METERS)
BY MON MORNING TO SUGGEST A MARGINAL HIGH WIND EVENT ACROSS THE WIND
PRONE AREAS.  HOWEVER...THE BETTER CHANCE OF HIGH WINDS WILL BE LATE
MON NIGHT INTO TUES AS THE LLVL GRADIENT INCREASES FURTHER TO 75-80
METERS AND FLOW ALOFT IS STRONGER.  THERE IS EVEN THE POTENTIAL FOR
HIGH WINDS TO SPREAD ONTO THE ADJACENT PLAINS OF SOUTHEAST WYOMING.
THE GRADIENT BEGINS TO DECREASE BY LATE TUES AS HIGHER PRESSURES AND
A COLD FRONT BACK INTO THE REGION.  TEMPS ON MON AND TUES WILL BE
ABOVE NORMAL WITH DOWNSLOPING WESTERLY WINDS PREVAILING.

THE OTHER STORY EARLY NEXT WEEK WILL BE THE OROGRAPHIC SNOWFALL
ACROSS THE SIERRA MADRE AND SNOWY RANGES.  MOIST NORTHWESTERLY FLOW
WILL TRANSPORT A GOOD AMOUNT OF PACIFIC MOISTURE INTO WYOMING.  BOTH
THE GFS AND ECMWF INDICATE A GOOD CHANCE OF SNOW THROUGH MIDDAY MON
AND THEN A BRIEF BREAK BEFORE MORE SNOW ARRIVES ON TUES AFTN.  SNOW
AMOUNTS (COMBINED WITH THE WINDY CONDITIONS) COULD WARRANT SOME SORT
OF WINTER WEATHER HEADLINE AT THAT TIME.  BY WED MORNING SNOW COULD
SPREAD ONTO THE PLAINS IN THE LLVL UPSLOPE BEHIND THE FRONT COMBINED
WITH SOME UPPER LEVEL SUPPORT. GENERALLY HAVE SLIGHT CHANCE POPS FOR
NOW ALONG WITH COOLER TEMPS.  IT IS A RATHER PROGRESSIVE PATTERN SO
INCREASING HEIGHTS AND TEMPS WILL OCCUR BY THURS AND FRI.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 530 AM MST SAT JAN 31 2015

MAINLY VFR CONDITIONS THROUGH THE EARLY AFTERNOON.  VFR CIGS WITH
BASES 5-10 THOUSAND FEET WILL BE COMMON THROUGH MIDDAY.  CIGS WILL
LOWER OVER MUCH OF THE REGION BY LATE THIS AFTERNOON AND AFTER 00Z
AS A COLD FRONT PUSHES ACROSS THE AREA.  LIGHT SNOW AND BRIEF IFR
VIS WILL BE POSSIBLE OVER PORTIONS OF THE NEBRASKA PANHANDLE.  WINDS
BEHIND THE FRONT WILL OCCASIONALLY GUST TO 25 KTS OVER THE PLAINS.

&&

.FIRE WEATHER...
ISSUED AT 530 AM MST SAT JAN 31 2015

SNOW SHOWERS WILL PERSIST OVER THE SNOWY AND SIERRA MADRE
MOUNTAINS THROUGH MUCH OF TODAY...WHILE RAIN AND SNOW SHOWERS WILL
DEVELOP OVER THE PLAINS AND HIGH VALLEYS THIS AFTERNOON AND EVENING.
SNOW ACCUMULATIONS WILL REMAIN GENERALLY LIGHT. SUNDAY WILL
REMAIN COOL AND MOSTLY DRY WITH WINDY CONDITIONS RETURNING TO THE
WIND PRONE AREAS OF SOUTHEAST WYOMING LATE SUNDAY NIGHT. WARM AND
WINDY CONDITIONS WILL CONTINUE FOR THE DISTRICT THROUGH MIDWEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...RJM




000
FXUS65 KCYS 311230
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
530 AM MST SAT JAN 31 2015

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 530 AM MST SAT JAN 31 2015

MADE A FEW CHANGES TO THE FORECAST FOR TODAY AS CURRENT WATER
VAPOR IMAGERY TRENDS SUGGEST ENERGY ASSOCIATED WITH THE SOUTHERN
STORM SYSTEM LOOKS TO LINGER OVER THE FORECAST AREA SLIGHTLY
LONGER THAN PREVIOUS THINKING. THE MIDLEVEL BAROCLINIC BAND ON
THE NORTHERN FRINGE OF THE UPPER LOW OVER THE DESERT SOUTHWEST IS
PROGGED TO REMAIN OVERHEAD THROUGH MIDDAY TODAY...WITH A SURFACE
TROUGH POSITIONED JUST SOUTHEAST OF THE FORECAST AREA EXTENDING
FROM CENTRAL COLORADO UP THRU CENTRAL NEBRASKA. SFC CYCLOGENESIS
OCCURRING OVER COLORADO TODAY WITHIN THIS TROUGH WILL PULL THE
MAIN COLD FRONT CURRENTLY OVER THE NORTHERN PLAINS SOUTH THRU THE
FORECAST AREA. SOUTHEASTERLY FLOW AT 700 MB OVER THE PLAINS AHEAD
OF THE MIDLEVEL FRONT WILL ADVECT IN SOME MOISTURE THIS MORNING
WITH WEAK ISENTROPIC LIFT DEVELOPING THROUGH THE DAY OVER THE
PANHANDLE AS THE SFC FRONT STEADILY SHIFTS SOUTH. THE MAIN PRECIP
BAND LOOKS TO DEVELOP OVER THE SOUTHERN PANHANDLE THIS MORNING
WITHIN THE AREA OF ISENTROPIC LIFT...AND THEN SHIFTS NORTH A BIT
INTO THE CENTRAL PANHANDLE THIS AFTERNOON BEFORE THE NORTHERN
STREAM SHORTWAVE FINALLY NUDGES THE MIDLEVEL FRONT AND ASSOCIATED
PRECIP BAND EAST EARLY THIS EVENING. SO BUMPED UP POPS AND SNOW
TOTALS ESPECIALLY ACROSS BOX BUTTE AND MORRILL COUNTIES WITHIN
MAIN AREA OF MIDLEVEL CONVERGENCE AND LIFT WHERE AROUND AN INCH OF
SNOW IS LIKELY THIS AFTERNOON. MODELS ALSO SHOW SOME WEAK
INSTABILITY IN THIS AREA AS WELL WHICH WILL AID IN OVERALL SHOWER
CHANCES. DO THINK PRECIP TYPE WILL BE MAJORITY SNOW BASED ON
TIMING OF THE SFC FRONT THIS MORNING...AND FORECAST SOUNDINGS
DEPICTING THE MAJORITY OF THE COLUMN WILL BE BELOW FREEZING.
CANNOT RULE OUT A MIX OF RAIN-SNOW AT THE ONSET OF PRECIP THO.
STILL EXPECTING SNOW SHOWERS TO CONTINUE IN THE SNOWY AND SIERRA
MADRES THIS MORNING AHEAD OF A SHORTWAVE MOVING UP FROM UTAH INTO
WESTERN CO.

THE NORTHERN STREAM SHORTWAVE TROUGH WILL SLIDE SOUTHEAST OVER THE
FORECAST AREA THIS EVENING WITH SHOWERS REDEVELOPING OVER MUCH OF
THE CWA THROUGH THE EVENING AND OVERNIGHT PERIOD. EXPECTING A
QUICK BURST OF SNOW WITH ANY SHOWER THAT OCCURS WITH ACCUMULATIONS
LOOKING TO GENERALLY BE ONE HALF INCH OR LESS IN THE LOWER
ELEVATIONS...AND AN INCH OR TWO IN THE MOUNTAINS. THE WAVE WILL
DEPART THE AREA QUICKLY SUNDAY MORNING WITH DRY AND COOLER
CONDITIONS ANTICIPATED FOR THE REST OF SUNDAY. HIGH PRESSURE WILL
BUILD OVER THE ROCKIES SUNDAY NIGHT WITH A WEAK DISTURBANCE MOVING
ATOP THE RIDGE AND OVER THE ROCKIES THROUGH THIS TIME. THE LEESIDE
PRESSURE TROUGH WILL DEEPEN QUITE RAPIDLY AHEAD OF THIS WAVE WITH
THE LLVL PRESSURE GRADIENT STRENGTHENING AS A RESULT. BY 06Z
MONDAY...THE CAG-CPR GRADIENT WILL BE ROUGHLY 55-60 DAM WITH WINDS
IN THE 750 TO 700 MB LAYER PROGGED TO BE IN EXCESS OF 50 KTS
THROUGH 12Z. A CROSS-SECTION PLOT THROUGH THE WIND PRONE AREAS
SHOW THE INVERSION SETTING UP JUST AROUND MOUNTAIN TOP LEVEL AND
WITHIN THE BAND OF STRONGER WINDS. SO...LOOKING AT PERHAPS A
MARGINAL HIGH WIND EVENT LATE SUNDAY NIGHT THROUGH MONDAY MORNING.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 530 AM MST SAT JAN 31 2015

THE EARLY PART OF NEXT WEEK WILL FEATURE WINDY CONDITIONS ACROSS
SOUTHEAST WYOMING AND INTERMITTENT SNOWS...MAINLY ACROSS THE MTNS.
THE LLVL CAG-CPR GRADIENT WILL BECOME HIGH ENOUGH (AROUND 60 METERS)
BY MON MORNING TO SUGGEST A MARGINAL HIGH WIND EVENT ACROSS THE WIND
PRONE AREAS.  HOWEVER...THE BETTER CHANCE OF HIGH WINDS WILL BE LATE
MON NIGHT INTO TUES AS THE LLVL GRADIENT INCREASES FURTHER TO 75-80
METERS AND FLOW ALOFT IS STRONGER.  THERE IS EVEN THE POTENTIAL FOR
HIGH WINDS TO SPREAD ONTO THE ADJACENT PLAINS OF SOUTHEAST WYOMING.
THE GRADIENT BEGINS TO DECREASE BY LATE TUES AS HIGHER PRESSURES AND
A COLD FRONT BACK INTO THE REGION.  TEMPS ON MON AND TUES WILL BE
ABOVE NORMAL WITH DOWNSLOPING WESTERLY WINDS PREVAILING.

THE OTHER STORY EARLY NEXT WEEK WILL BE THE OROGRAPHIC SNOWFALL
ACROSS THE SIERRA MADRE AND SNOWY RANGES.  MOIST NORTHWESTERLY FLOW
WILL TRANSPORT A GOOD AMOUNT OF PACIFIC MOISTURE INTO WYOMING.  BOTH
THE GFS AND ECMWF INDICATE A GOOD CHANCE OF SNOW THROUGH MIDDAY MON
AND THEN A BRIEF BREAK BEFORE MORE SNOW ARRIVES ON TUES AFTN.  SNOW
AMOUNTS (COMBINED WITH THE WINDY CONDITIONS) COULD WARRANT SOME SORT
OF WINTER WEATHER HEADLINE AT THAT TIME.  BY WED MORNING SNOW COULD
SPREAD ONTO THE PLAINS IN THE LLVL UPSLOPE BEHIND THE FRONT COMBINED
WITH SOME UPPER LEVEL SUPPORT. GENERALLY HAVE SLIGHT CHANCE POPS FOR
NOW ALONG WITH COOLER TEMPS.  IT IS A RATHER PROGRESSIVE PATTERN SO
INCREASING HEIGHTS AND TEMPS WILL OCCUR BY THURS AND FRI.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 530 AM MST SAT JAN 31 2015

MAINLY VFR CONDITIONS THROUGH THE EARLY AFTERNOON.  VFR CIGS WITH
BASES 5-10 THOUSAND FEET WILL BE COMMON THROUGH MIDDAY.  CIGS WILL
LOWER OVER MUCH OF THE REGION BY LATE THIS AFTERNOON AND AFTER 00Z
AS A COLD FRONT PUSHES ACROSS THE AREA.  LIGHT SNOW AND BRIEF IFR
VIS WILL BE POSSIBLE OVER PORTIONS OF THE NEBRASKA PANHANDLE.  WINDS
BEHIND THE FRONT WILL OCCASIONALLY GUST TO 25 KTS OVER THE PLAINS.

&&

.FIRE WEATHER...
ISSUED AT 530 AM MST SAT JAN 31 2015

SNOW SHOWERS WILL PERSIST OVER THE SNOWY AND SIERRA MADRE
MOUNTAINS THROUGH MUCH OF TODAY...WHILE RAIN AND SNOW SHOWERS WILL
DEVELOP OVER THE PLAINS AND HIGH VALLEYS THIS AFTERNOON AND EVENING.
SNOW ACCUMULATIONS WILL REMAIN GENERALLY LIGHT. SUNDAY WILL
REMAIN COOL AND MOSTLY DRY WITH WINDY CONDITIONS RETURNING TO THE
WIND PRONE AREAS OF SOUTHEAST WYOMING LATE SUNDAY NIGHT. WARM AND
WINDY CONDITIONS WILL CONTINUE FOR THE DISTRICT THROUGH MIDWEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...RJM




000
FXUS65 KCYS 311230
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
530 AM MST SAT JAN 31 2015

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 530 AM MST SAT JAN 31 2015

MADE A FEW CHANGES TO THE FORECAST FOR TODAY AS CURRENT WATER
VAPOR IMAGERY TRENDS SUGGEST ENERGY ASSOCIATED WITH THE SOUTHERN
STORM SYSTEM LOOKS TO LINGER OVER THE FORECAST AREA SLIGHTLY
LONGER THAN PREVIOUS THINKING. THE MIDLEVEL BAROCLINIC BAND ON
THE NORTHERN FRINGE OF THE UPPER LOW OVER THE DESERT SOUTHWEST IS
PROGGED TO REMAIN OVERHEAD THROUGH MIDDAY TODAY...WITH A SURFACE
TROUGH POSITIONED JUST SOUTHEAST OF THE FORECAST AREA EXTENDING
FROM CENTRAL COLORADO UP THRU CENTRAL NEBRASKA. SFC CYCLOGENESIS
OCCURRING OVER COLORADO TODAY WITHIN THIS TROUGH WILL PULL THE
MAIN COLD FRONT CURRENTLY OVER THE NORTHERN PLAINS SOUTH THRU THE
FORECAST AREA. SOUTHEASTERLY FLOW AT 700 MB OVER THE PLAINS AHEAD
OF THE MIDLEVEL FRONT WILL ADVECT IN SOME MOISTURE THIS MORNING
WITH WEAK ISENTROPIC LIFT DEVELOPING THROUGH THE DAY OVER THE
PANHANDLE AS THE SFC FRONT STEADILY SHIFTS SOUTH. THE MAIN PRECIP
BAND LOOKS TO DEVELOP OVER THE SOUTHERN PANHANDLE THIS MORNING
WITHIN THE AREA OF ISENTROPIC LIFT...AND THEN SHIFTS NORTH A BIT
INTO THE CENTRAL PANHANDLE THIS AFTERNOON BEFORE THE NORTHERN
STREAM SHORTWAVE FINALLY NUDGES THE MIDLEVEL FRONT AND ASSOCIATED
PRECIP BAND EAST EARLY THIS EVENING. SO BUMPED UP POPS AND SNOW
TOTALS ESPECIALLY ACROSS BOX BUTTE AND MORRILL COUNTIES WITHIN
MAIN AREA OF MIDLEVEL CONVERGENCE AND LIFT WHERE AROUND AN INCH OF
SNOW IS LIKELY THIS AFTERNOON. MODELS ALSO SHOW SOME WEAK
INSTABILITY IN THIS AREA AS WELL WHICH WILL AID IN OVERALL SHOWER
CHANCES. DO THINK PRECIP TYPE WILL BE MAJORITY SNOW BASED ON
TIMING OF THE SFC FRONT THIS MORNING...AND FORECAST SOUNDINGS
DEPICTING THE MAJORITY OF THE COLUMN WILL BE BELOW FREEZING.
CANNOT RULE OUT A MIX OF RAIN-SNOW AT THE ONSET OF PRECIP THO.
STILL EXPECTING SNOW SHOWERS TO CONTINUE IN THE SNOWY AND SIERRA
MADRES THIS MORNING AHEAD OF A SHORTWAVE MOVING UP FROM UTAH INTO
WESTERN CO.

THE NORTHERN STREAM SHORTWAVE TROUGH WILL SLIDE SOUTHEAST OVER THE
FORECAST AREA THIS EVENING WITH SHOWERS REDEVELOPING OVER MUCH OF
THE CWA THROUGH THE EVENING AND OVERNIGHT PERIOD. EXPECTING A
QUICK BURST OF SNOW WITH ANY SHOWER THAT OCCURS WITH ACCUMULATIONS
LOOKING TO GENERALLY BE ONE HALF INCH OR LESS IN THE LOWER
ELEVATIONS...AND AN INCH OR TWO IN THE MOUNTAINS. THE WAVE WILL
DEPART THE AREA QUICKLY SUNDAY MORNING WITH DRY AND COOLER
CONDITIONS ANTICIPATED FOR THE REST OF SUNDAY. HIGH PRESSURE WILL
BUILD OVER THE ROCKIES SUNDAY NIGHT WITH A WEAK DISTURBANCE MOVING
ATOP THE RIDGE AND OVER THE ROCKIES THROUGH THIS TIME. THE LEESIDE
PRESSURE TROUGH WILL DEEPEN QUITE RAPIDLY AHEAD OF THIS WAVE WITH
THE LLVL PRESSURE GRADIENT STRENGTHENING AS A RESULT. BY 06Z
MONDAY...THE CAG-CPR GRADIENT WILL BE ROUGHLY 55-60 DAM WITH WINDS
IN THE 750 TO 700 MB LAYER PROGGED TO BE IN EXCESS OF 50 KTS
THROUGH 12Z. A CROSS-SECTION PLOT THROUGH THE WIND PRONE AREAS
SHOW THE INVERSION SETTING UP JUST AROUND MOUNTAIN TOP LEVEL AND
WITHIN THE BAND OF STRONGER WINDS. SO...LOOKING AT PERHAPS A
MARGINAL HIGH WIND EVENT LATE SUNDAY NIGHT THROUGH MONDAY MORNING.

.LONG TERM...(MONDAY THROUGH FRIDAY)
ISSUED AT 530 AM MST SAT JAN 31 2015

THE EARLY PART OF NEXT WEEK WILL FEATURE WINDY CONDITIONS ACROSS
SOUTHEAST WYOMING AND INTERMITTENT SNOWS...MAINLY ACROSS THE MTNS.
THE LLVL CAG-CPR GRADIENT WILL BECOME HIGH ENOUGH (AROUND 60 METERS)
BY MON MORNING TO SUGGEST A MARGINAL HIGH WIND EVENT ACROSS THE WIND
PRONE AREAS.  HOWEVER...THE BETTER CHANCE OF HIGH WINDS WILL BE LATE
MON NIGHT INTO TUES AS THE LLVL GRADIENT INCREASES FURTHER TO 75-80
METERS AND FLOW ALOFT IS STRONGER.  THERE IS EVEN THE POTENTIAL FOR
HIGH WINDS TO SPREAD ONTO THE ADJACENT PLAINS OF SOUTHEAST WYOMING.
THE GRADIENT BEGINS TO DECREASE BY LATE TUES AS HIGHER PRESSURES AND
A COLD FRONT BACK INTO THE REGION.  TEMPS ON MON AND TUES WILL BE
ABOVE NORMAL WITH DOWNSLOPING WESTERLY WINDS PREVAILING.

THE OTHER STORY EARLY NEXT WEEK WILL BE THE OROGRAPHIC SNOWFALL
ACROSS THE SIERRA MADRE AND SNOWY RANGES.  MOIST NORTHWESTERLY FLOW
WILL TRANSPORT A GOOD AMOUNT OF PACIFIC MOISTURE INTO WYOMING.  BOTH
THE GFS AND ECMWF INDICATE A GOOD CHANCE OF SNOW THROUGH MIDDAY MON
AND THEN A BRIEF BREAK BEFORE MORE SNOW ARRIVES ON TUES AFTN.  SNOW
AMOUNTS (COMBINED WITH THE WINDY CONDITIONS) COULD WARRANT SOME SORT
OF WINTER WEATHER HEADLINE AT THAT TIME.  BY WED MORNING SNOW COULD
SPREAD ONTO THE PLAINS IN THE LLVL UPSLOPE BEHIND THE FRONT COMBINED
WITH SOME UPPER LEVEL SUPPORT. GENERALLY HAVE SLIGHT CHANCE POPS FOR
NOW ALONG WITH COOLER TEMPS.  IT IS A RATHER PROGRESSIVE PATTERN SO
INCREASING HEIGHTS AND TEMPS WILL OCCUR BY THURS AND FRI.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 530 AM MST SAT JAN 31 2015

MAINLY VFR CONDITIONS THROUGH THE EARLY AFTERNOON.  VFR CIGS WITH
BASES 5-10 THOUSAND FEET WILL BE COMMON THROUGH MIDDAY.  CIGS WILL
LOWER OVER MUCH OF THE REGION BY LATE THIS AFTERNOON AND AFTER 00Z
AS A COLD FRONT PUSHES ACROSS THE AREA.  LIGHT SNOW AND BRIEF IFR
VIS WILL BE POSSIBLE OVER PORTIONS OF THE NEBRASKA PANHANDLE.  WINDS
BEHIND THE FRONT WILL OCCASIONALLY GUST TO 25 KTS OVER THE PLAINS.

&&

.FIRE WEATHER...
ISSUED AT 530 AM MST SAT JAN 31 2015

SNOW SHOWERS WILL PERSIST OVER THE SNOWY AND SIERRA MADRE
MOUNTAINS THROUGH MUCH OF TODAY...WHILE RAIN AND SNOW SHOWERS WILL
DEVELOP OVER THE PLAINS AND HIGH VALLEYS THIS AFTERNOON AND EVENING.
SNOW ACCUMULATIONS WILL REMAIN GENERALLY LIGHT. SUNDAY WILL
REMAIN COOL AND MOSTLY DRY WITH WINDY CONDITIONS RETURNING TO THE
WIND PRONE AREAS OF SOUTHEAST WYOMING LATE SUNDAY NIGHT. WARM AND
WINDY CONDITIONS WILL CONTINUE FOR THE DISTRICT THROUGH MIDWEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RJM
LONG TERM...ZF
AVIATION...ZF
FIRE WEATHER...RJM




000
FXUS63 KUNR 311113
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
413 AM MST SAT JAN 31 2015

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 349 AM MST SAT JAN 31 2015

UPPER LEVEL ANALYSIS HAS UPPER LOW ACROSS THE SOUTHWEST CONUS WITH
NORTHWEST FLOW ACROSS THE NORTHERN CONUS. SKIES ARE CLOUDY ACROSS
THE NORTHERN PLAINS WITH LOW STRATUS DECK SLIDING SOUTH ACROSS THE
DAKOTAS. AT THE SURFACE...BACK-DOOR COLD FRONT IS CURRENTLY
DROPPING SOUTH ACROSS SOUTH DAKOTA...WITH WINDS TURNING NORTHEAST
BEHIND THE FRONT. TEMPERATURES ARE MAINLY IN THE 20S.

TODAY...UPPER RIDGE SHIFTS SOUTHEAST AS CUT-OFF LOW DEVELOPS
ACROSS THE SOUTHWEST CONUS. SURFACE COLD FRONT AND STRATUS DECK
WILL CONTINUE TO DROP SOUTHWEST ACROSS THE WESTERN SOUTH DAKOTA
PLAINS. COOLER AIR WILL FILTER INTO THE AREA BEHIND THE
FRONT...AND ALONG WITH THE CLOUD COVER...AREAS ACROSS THE SOUTH
DAKOTA PLAINS WILL REMAIN IN THE 20S FOR TODAY. FURTHER WEST IN
WYOMING...HIGH TEMPERATURES WILL BE MILDER...IN THE LOWER 40S.
STRONG NORTHERN STREAM IMPULSE WILL SLIDE THROUGH THE NORTHERN
PLAINS LATE TODAY INTO TONIGHT. THIS FEATURE WITH AN ASSOCIATED
STRONG JET STREAK WILL FORCE A PERIOD OF LIGHT SNOW OVER THE AREA
TONIGHT. IN ADDITION...A DEVELOPING SURFACE LOW WILL SKIRT SOUTH
CENTRAL SOUTH DAKOTA...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-3 INCH
RANGE...HIGHEST ACROSS THE NORTHERN BLACK HILLS AND ACROSS TRIPP
COUNTY.

SUNDAY...UPPER SHORTWAVE SHIFTS QUICKLY EAST...WITH SOME LIGHT
SNOW POSSIBLY LINGERING ACROSS THE NORTHERN BLACK HILLS AND FAR
SOUTH CENTRAL SOUTH DAKOTA DURING THE MORNING. WEAK UPPER RIDGE
BUILDS ACROSS THE ROCKIES WITH SKIES BECOMING MOSTLY SUNNY LATE
IN THE DAY. ARCTIC HIGH REMAINS ACROSS THE AREA WITH HIGH
TEMPERATURES ONLY IN THE TEENS ACROSS THE SOUTH DAKOTA
PLAINS...AND IN THE 20S ACROSS NORTHEAST WYOMING. LOWS SUNDAY
NIGHT WILL FALL INTO THE 5 TO 20 DEGREE RANGE.


.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 349 AM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD...BECOMING MORE ZONAL TOWARD THE END OF
THE WEEK. A RELATIVELY WEAK SHORTWAVE WILL BRING A SLIGHT CHANCE
OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY. A
BETTER DEFINED UPPER TROUGH WILL AFFECT THE AREA ON TUESDAY NIGHT
AS A COLD FRONT MOVES THROUGH AT THE SURFACE...BRINGING A CHANCE
OF SNOW TO THE AREA. AT THIS TIME IT LOOKS LIKE THE BEST AREA FOR
MEASURABLE SNOW ACCUMULATION WOULD BE OVER PARTS OF NORTHEASTERN
WYOMING AND SOUTHWESTERN SOUTH DAKOTA. DRY WEATHER IS THEN
EXPECTED THROUGH THE REST OF THE WEEK.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...THEN BECOMING COLDER THAN AVERAGE BEHIND THE
COLD FRONT ON WEDNESDAY. THE BOUNDARY WILL THEN SHIFT NORTHEASTWARD
AGAIN WITH MUCH WARMER THAN AVERAGE TEMPERATURES EXPECTED ON FRIDAY.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING
ISSUED AT 349 AM MST SAT JAN 31 2015

AREA OF IFR/MVFR STRATUS OVER NERN AND NCNTRL SD WILL SINK INTO
WESTERN SOUTH DAKOTA THIS MORNING...REACHING THE BLACK HILLS
AROUND 15Z THEN CONTINUING TO SINK SOUTHWEST THROUGH THIS EVENING.
LIGHT SNOW WILL SPREAD ACROSS MUCH OF THE AREA FROM LATE THIS
AFTERNOON THROUGH TONIGHT...RESULTING IN WIDESPREAD IFR
CONDITIONS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...15
LONG TERM...10
AVIATION...10






000
FXUS63 KUNR 311113
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
413 AM MST SAT JAN 31 2015

.SHORT TERM...TODAY THROUGH SUNDAY NIGHT
ISSUED AT 349 AM MST SAT JAN 31 2015

UPPER LEVEL ANALYSIS HAS UPPER LOW ACROSS THE SOUTHWEST CONUS WITH
NORTHWEST FLOW ACROSS THE NORTHERN CONUS. SKIES ARE CLOUDY ACROSS
THE NORTHERN PLAINS WITH LOW STRATUS DECK SLIDING SOUTH ACROSS THE
DAKOTAS. AT THE SURFACE...BACK-DOOR COLD FRONT IS CURRENTLY
DROPPING SOUTH ACROSS SOUTH DAKOTA...WITH WINDS TURNING NORTHEAST
BEHIND THE FRONT. TEMPERATURES ARE MAINLY IN THE 20S.

TODAY...UPPER RIDGE SHIFTS SOUTHEAST AS CUT-OFF LOW DEVELOPS
ACROSS THE SOUTHWEST CONUS. SURFACE COLD FRONT AND STRATUS DECK
WILL CONTINUE TO DROP SOUTHWEST ACROSS THE WESTERN SOUTH DAKOTA
PLAINS. COOLER AIR WILL FILTER INTO THE AREA BEHIND THE
FRONT...AND ALONG WITH THE CLOUD COVER...AREAS ACROSS THE SOUTH
DAKOTA PLAINS WILL REMAIN IN THE 20S FOR TODAY. FURTHER WEST IN
WYOMING...HIGH TEMPERATURES WILL BE MILDER...IN THE LOWER 40S.
STRONG NORTHERN STREAM IMPULSE WILL SLIDE THROUGH THE NORTHERN
PLAINS LATE TODAY INTO TONIGHT. THIS FEATURE WITH AN ASSOCIATED
STRONG JET STREAK WILL FORCE A PERIOD OF LIGHT SNOW OVER THE AREA
TONIGHT. IN ADDITION...A DEVELOPING SURFACE LOW WILL SKIRT SOUTH
CENTRAL SOUTH DAKOTA...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-3 INCH
RANGE...HIGHEST ACROSS THE NORTHERN BLACK HILLS AND ACROSS TRIPP
COUNTY.

SUNDAY...UPPER SHORTWAVE SHIFTS QUICKLY EAST...WITH SOME LIGHT
SNOW POSSIBLY LINGERING ACROSS THE NORTHERN BLACK HILLS AND FAR
SOUTH CENTRAL SOUTH DAKOTA DURING THE MORNING. WEAK UPPER RIDGE
BUILDS ACROSS THE ROCKIES WITH SKIES BECOMING MOSTLY SUNNY LATE
IN THE DAY. ARCTIC HIGH REMAINS ACROSS THE AREA WITH HIGH
TEMPERATURES ONLY IN THE TEENS ACROSS THE SOUTH DAKOTA
PLAINS...AND IN THE 20S ACROSS NORTHEAST WYOMING. LOWS SUNDAY
NIGHT WILL FALL INTO THE 5 TO 20 DEGREE RANGE.


.LONG TERM...MONDAY THROUGH FRIDAY
ISSUED AT 349 AM MST SAT JAN 31 2015

NW FLOW ALOFT WILL CONTINUE OVER THE FORECAST AREA THROUGH THE
EXTENDED FORECAST PERIOD...BECOMING MORE ZONAL TOWARD THE END OF
THE WEEK. A RELATIVELY WEAK SHORTWAVE WILL BRING A SLIGHT CHANCE
OF SNOW OR RAIN TO THE FORECAST AREA ON MONDAY AND TUESDAY. A
BETTER DEFINED UPPER TROUGH WILL AFFECT THE AREA ON TUESDAY NIGHT
AS A COLD FRONT MOVES THROUGH AT THE SURFACE...BRINGING A CHANCE
OF SNOW TO THE AREA. AT THIS TIME IT LOOKS LIKE THE BEST AREA FOR
MEASURABLE SNOW ACCUMULATION WOULD BE OVER PARTS OF NORTHEASTERN
WYOMING AND SOUTHWESTERN SOUTH DAKOTA. DRY WEATHER IS THEN
EXPECTED THROUGH THE REST OF THE WEEK.

THE TEMPERATURE FORECAST REMAINS TRICKY AS A SURFACE FRONTAL
BOUNDARY FLUCTUATES ACROSS THE FORECAST AREA WITH A WIDE VARIATION
IN TEMPERATURES ON EITHER SIDE OF THE BOUNDARY. AT THIS TIME IT LOOKS
LIKE HIGH TEMPERATURES WILL MAINLY BE SLIGHTLY WARMER THAN AVERAGE
ON MONDAY AND TUESDAY...THEN BECOMING COLDER THAN AVERAGE BEHIND THE
COLD FRONT ON WEDNESDAY. THE BOUNDARY WILL THEN SHIFT NORTHEASTWARD
AGAIN WITH MUCH WARMER THAN AVERAGE TEMPERATURES EXPECTED ON FRIDAY.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING
ISSUED AT 349 AM MST SAT JAN 31 2015

AREA OF IFR/MVFR STRATUS OVER NERN AND NCNTRL SD WILL SINK INTO
WESTERN SOUTH DAKOTA THIS MORNING...REACHING THE BLACK HILLS
AROUND 15Z THEN CONTINUING TO SINK SOUTHWEST THROUGH THIS EVENING.
LIGHT SNOW WILL SPREAD ACROSS MUCH OF THE AREA FROM LATE THIS
AFTERNOON THROUGH TONIGHT...RESULTING IN WIDESPREAD IFR
CONDITIONS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...15
LONG TERM...10
AVIATION...10







000
FXUS65 KRIW 310950
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
250 AM MST SAT JAN 31 2015

.SHORT TERM...TODAY THROUGH MONDAY NIGHT

ANY LEFT OVER SNOWFALL IN SOUTHERN SWEETWATER COUNTY THIS MORNING
WILL SHUT OFF SHORTLY AFTER SUNRISE AS THE LOW OVER VEGAS PROPAGATES
SOUTH TO OLD MEXICO. THE ASCT HIGH AND MID CLOUDS THAT HAVE BEEN
OVER CENTRAL AND SOUTHERN WY FRIDAY WILL CLEAR OUT OF SWEETWATER AND
NATRONA COUNTIES TO THE SOUTHEAST WITH MOSTLY CLEAR SKIES BY 18Z
TODAY. OTHERWISE EXPECT A MOSTLY SUNNY DAY WITH LIGHT WINDS AND
RELATIVELY MILD TEMPERATURES TODAY. THE NORTHERN STREAM VORT OVER
SOUTHERN BC WILL TRACK ACROSS WY FROM THE NW BY 00Z SAT. THIS
WEATHER FEATURE WILL DELIVER PATCHY LIGHT SNOW TO AREAS NORTH AND
EAST OF THE DIVIDE TONIGHT AS IT DRIVES A COLD FRONT SOUTH AND H7
TEMPS DROP TO -16C IN JOHNSON COUNTY BY 12Z SUNDAY. POST FRONTAL NNW
WINDS WILL INCREASE IN JOHNSON COUNTY LATE TODAY. SUNDAY WILL BE
RELATIVELY CHILLY WITH WARM AIR ADVECTING IN ALOFT FROM THE
SOUTHWEST SO THE COOLER AIR WILL BE SHORT LIVED. NORTHERN AND
WESTERN WY MAY NOT BREAK FREEZING SUNDAY BEFORE WARMING BACK UP
MONDAY. STILL...SEASONABLE TEMPS SLATED FOR THIS TIME OF YEAR
SUNDAY. BY SUNDAY NIGHT THE STEERING FLOW WILL BACK FROM NW TO WEST
AND INCREASE IN SPEED...MORE DIRECTLY OFF THE PACIFIC  UNDER A
FLATTENING RIDGE. A BATCH OF PACIFIC MOISTURE COMBINED WITH A WEAK
VORT EMBEDDED IN THE BACKING FLOW...SNOW WILL INCREASE IN THE WEST
SUNDAY NIGHT. SNOW WILL LESSEN IN INTENSITY MONDAY IN THE FAR WEST.
THEN THE CIRCULATION NOW WELL OFF THE PACIFIC COAST AT 45N/152W WILL
ARRIVE AS A VIGOROUS SHORTWAVE BRINGING ANOTHER SLUG OF PACIFIC
MOISTURE ACROSS MT/WY MONDAY NIGHT WITH SNOWFALL INCREASING ONCE
AGAIN IN THE FAR WEST. WITH FAVORABLE UPSLOPE CONDITIONS FOR THE FAR
WEST SUNDAY NIGHT THROUGH MONDAY NIGHT WITH THESE TWO BACK TO BACK
PACIFIC SYSTEMS...THERE WILL BE A POTENTIAL OF ACCUMULATING SNOWFALL
FOR THE FAR WEST AND WILL HAVE TO BE MONITORED. THERE WILL BE SOME
ISENTROPIC LIFT IN THE FAR WEST MONDAY NIGHT AS WELL WITH THE SECOND
PACIFIC SYSTEM.

.LONG TERM...TUESDAY THROUGH SATURDAY

THE OVERALL BIG PICTURE IS REASONABLY SIMILAR IN THE MODELS TONIGHT
BUT THE TIMING/SPEED VARIES ENOUGH TO MAKE THE FORECAST A CHALLENGE.
OVERALL...IT STILL LOOKS LIKE A COLD SHORTWAVE AND ASSOCIATED COLD
FRONT WILL DROP SOUTH OUT OF CANADA ON TUESDAY INTO TUESDAY NIGHT
WITH POTENTIAL FOR UPSLOPE EAST OF THE DIVIDE...ESPECIALLY IN THE
NORTH. IN THE WEST...A MOIST W-NW FLOW WILL KEEP SNOW FLYING OUT
THERE WITH STRONG W-NW WIND AHEAD OF THE CANADIAN FRONT EAST OF THE
DIVIDE. GFS HAS MORE AMPLIFICATION OF THE UPSTREAM RIDGE WEDNESDAY
WITH A COLDER...CYCLONIC NW FLOW WHILE THE ECMWF PUSHES THE RIDGE
AXIS MORE QUICKLY OFF TO THE EAST WITH LESS AMPLIFICATION. THE GEM
IS MORE OF A COMPROMISE. WILL GRADUALLY PUSH THE POPS SWD INTO
WEDNESDAY TO MAINLY COVER THE WEST AND SOUTH HALF. AS THE RIDGE AXIS
STARTS TO MOVE IN WEDNESDAY NIGHT SOME ISENTROPIC UPGLIDE MAY BE
ENOUGH FOR SOME LIGHT MTN SNOWFALL OUT WEST. DRIEST DAY IS SHAPING
UP TO BE THURSDAY WITH RIDGE AXIS INTO THE WEST. ECMWF KEEPS THE DRY
RIDGE AXIS OVER US THROUGH FRIDAY WHILE THE GFS IS FLATTER AND MORE
MOIST WITH PERSISTENT AT LEAST LIGHT PCPN OUT WEST. DUE TO THE
UNCERTAINTY THIS FAR OUT WILL KEEP JUST SOME POPS OUT WEST.
POTENTIAL FOR VALLEY RAIN OR SNOW AND MOUNTAIN SNOW INCREASING ONCE
AGAIN BY SATURDAY WITH POTENTIAL SHORTWAVE OR TWO SPINNING OFF THE
ERN PACIFIC TROUGH AND MOVING EAST ACROSS THE AREA. OVERALL...THIS
PATTERN COULD KEEP AREAS EAST OF THE DIVIDE MIXED OFF AND ON WITH
MILD TEMPERATURES. WINDY AHEAD OF THE CANADIAN FRONT TUESDAY. BRIEF
COLDER AIR WEDNESDAY WITH DECENT SURFACE HIGH JUST TO THE NE...THEN
WARM AIR ALOFT MOVING IN AGAIN BY THURSDAY THROUGH SATURDAY WITH
POTENTIAL FOR ENOUGH FLOW ALOFT AND PRESSURE GRADIENT TO KEEP
QUITE A FEW AREAS EAST OF THE DIVIDE MIXED...ESPECIALLY FRIDAY AND
SATURDAY. GENERALLY GOING WITH 40S AND SOME 50S EAST OF THE DIVIDE
FOR FRIDAY AND SATURDAY. COOLER IN THE WEST WITH INVERSIONS
HOLDING IN BETWEEN SYSTEMS AND THEN OF COURSE COLD RAIN OR SNOW AT
TIMES WITH EACH SYSTEM. SO MAINLY 30S OUT WEST.

&&

.AVIATION.../12Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

AREAS OF FOG WILL OBSCURE TERRAIN ACROSS THE LOWER BIGHORN BASIN
THROUGH 14Z...VCNTY KGEY-KWRL.  A COLD FRONT WILL PUSH SOUTH ACROSS
NORTHERN WYOMING LATE THIS MORNING...LIKELY SCOURING OUT ANY
LINGERING FOG. HOWEVER...AREAS OF LOWER MVFR/IFR CIGS AND -SN WILL
FOLLOW THE FRONT INTO NORTHERN WYOMING AFTER 20Z...AND SOUTHWARD
TO NEAR A VCNTY KRIW-KCPR LINE BY 00Z SUNDAY. AREAS OF LOWER
MVFR/IFR CIGS...LCL LIFR CIGS/FG WILL LIKELY REMAIN AGAINST THE
EAST SLOPES OF THE DIVIDE THROUGH 12Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

AREAS OF IFR/MVFR CIGS AND -SN WILL GRADUALLY DECREASE ACROSS THE
INTERSTATE 80 CORRIDOR THROUGH 14Z...BUT PATCHY FOG MAY LINGER IN
THIS AREA THROUGH THE MORNING.  OTHERWISE...VFR CONDITIONS WILL
PREVAIL ACROSS THE AREA 15Z TODAY-03Z SUNDAY. A COLD FRONT WILL
PLUNGE DOWN THE EAST SLOPES OF THE DIVIDE LATE THIS MORNING
THROUGH THIS AFTERNOON WITH SOME MTN OBSCURATIONS POSSIBLE ALONG
THE DIVIDE. THIS FRONT MAY PUSH LOWER MVFR/IFR CIGS INTO VCNTY
KRKS AFTER 06Z SUNDAY. FURTHER OUT FROM THE FRONT....LOWER
MVFR/IFR CIGS FROM EASTERN IDAHO MAY PUSH INTO THE FAR
WEST...VCNTY KJAC-KAFO AFTER 03Z SUNDAY.

&&

.FIRE WEATHER...
FIRE DANGER IS LOW FOR ALL AREAS...AND WILL REMAIN SO THROUGH NEXT
WEEK. MEASURABLE PRECIPITATION WILL NOT FALL ACROSS THE FORECAST
AREA UNTIL LATE TODAY INTO SUNDAY MORNING EAST OF THE DIVIDE.
FROM SUNDAY NIGHT THROUGH THE NEXT WORK WEEK...A SERIES OF
DISTURBANCES WILL RIDE THROUGH THE REGION...AFFECTING MAINLY THE
WESTERN AND NORTHERN DISPATCH ZONES. TODAY WILL SEE IMPROVEMENT
IN BOTH MIXING ABILITY AND DISPERSION...ESPECIALLY EAST OF THE
DIVIDE AND ACROSS THE SOUTHERN ZONES.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

SHORT TERM...LIPSON
LONG TERM...PS
AVIATION...AEM
FIRE WEATHER...LIPSON








000
FXUS65 KRIW 310654
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1154 PM MST FRI JAN 30 2015

UPDATE...ADDED 06Z AVIATION DISCUSSION.

.SHORT TERM...TONIGHT THROUGH SATURDAY (ISSUED AT 230 PM MST)

A WARM PACIFIC LOW OVER THE FOUR CORNERS AREA THIS
AFTERNOON...CONTINUES TO STREAM HIGH CLOUDS ACROSS THE COWBOY
STATE. LOW CLOUDS HAVE MADE THEIR WAY INTO THE I-80 CORRIDOR NEAR
KRKS...WHILE THE RAIN SHOWERS REMAIN WELL TO THE SOUTH IN NE
UT/NW CO. THESE SHOWERS WILL SLOWLY MAKE THEIR WAY NORTHWARD THIS
EVENING. TEMPERATURES ARE EXPECTED TO BE AT OR BELOW FREEZING BY
THIS TIME...PRODUCING LIGHT SNOW SHOWERS ACROSS SWEETWATER COUNTY.
ACCUMULATIONS ARE EXPECTED TO REMAIN LIGHT THROUGH MID MORNING
SATURDAY.

FOG CONTINUES TO HOLD ON OVER NORTHERN PORTIONS OF THE BIGHORN
BASIN...DESPITE THE CLOUDS ALOFT. FOG WILL BEGIN TO FILL IN
FURTHER SOUTH TOWARD KWRL DURING THE OVERNIGHT HOURS. FOG SHOULD
LIFT OUT BY MID MORNING...AS SKIES BEGIN TO CLEAR ACROSS THE AREA.

A COLD FRONT WILL BEGIN TO IMPACT NORTHERN PORTIONS LATE SATURDAY
AFTERNOON...BRINGING LOW CLOUDS AND GUSTY WINDS TO JOHNSON COUNTY.
LIGHT SNOW SHOWERS WILL BE POSSIBLE IN THE BIGHORNS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY NIGHT

THE SHORTWAVE MOVING THROUGH NORTHEASTERN WYOMING SATURDAY NIGHT
WILL HAVE SOME IMPACT OVER THE EASTERN PORTION OF THE FORECAST AREA
THROUGH SUNDAY MORNING. LIGHT SHOWER ACTIVITY IS EXPECTED.

BUILDING NORTHWEST FLOW THEN EXPECTED SUNDAY AFTERNOON AND EVENING
AS A RIDGE OF HIGH PRESSURE BUILDS OFF THE PACIFIC COAST. THIS
SYSTEM WILL BRING SOME MOISTURE INTO NORTHWESTERN WYOMING EARLY
MONDAY MORNING...MAINLY IMPACTING WESTERN AND NORTHERN WYOMING.

ANOTHER...MORE SIGNIFICANT PUSH OF MOISTURE WILL FOLLOW THAT SYSTEM
QUICKLY...WITH PRECIPITATION SPREADING INTO WESTERN WYOMING MONDAY
EVENING. ACTIVITY FROM THIS SYSTEM WILL LINGER THROUGH WEDNESDAY AS
ANOTHER PUSH COMES DOWN FROM THE NORTH AS WELL. THE ACTIVITY WILL
SPREAD TO INCLUDE MUCH OF THE FORECAST AREA. MODELS HAVE SOME
VARIATIONS ON THIS SYSTEM...WITH THE GFS REMAINING THE MOST
AGGRESSIVE MODEL. HOWEVER...ALL MODELS ARE IN FAIR AGREEMENT THAT
COVERAGE WILL INCREASE THROUGH WEDNESDAY MORNING.

CONDITIONS TO IMPROVE WEDNESDAY AFTERNOON AND EVENING. A BUILDING
RIDGE WILL HELP TO CLEAR OUT ACTIVITY...THOUGH SOME VERY LIGHT
ACTIVITY MAY REMAIN POSSIBLE ACROSS THE NORTHWEST THROUGH THURSDAY
AFTERNOON. DRY CONDITIONS EXPECTED BY FRIDAY MORNING...WHICH MAY NOT
LAST LONG.

&&

.AVIATION.../06Z ISSUANCE

AREAS OF FOG WILL OBSCURE TERRAIN ACROSS THE LOWER BIGHORN BASIN
THROUGH 14Z...VCNTY KGEY-KWRL.  A COLD FRONT WILL PUSH SOUTH ACROSS
NORTHERN WYOMING LATE SATURDAY MORNING...LIKELY SCOURING OUT ANY
LINGERING FOG.  HOWEVER...AREAS OF LOWER MVFR/IFR CIGS AND -SN WILL
FOLLOW THE FRONT INTO NORTHERN WYOMING AFTER 20Z...AND SOUTHWARD TO
NEAR A VCNTY KRIW-KCPR LINE BY 00Z SUNDAY.  AREAS OF LOWER MVFR/IFR
CIGS...LCL LIFR CIGS/FG WILL LIKELY REMAIN AGAINST THE EAST SLOPES
OF THE DIVIDE THROUGH 12Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

AREAS OF IFR/MVFR CIGS AND -SN WILL GRADUALLY DECREASE ACROSS THE
INTERSTATE 80 CORRIDOR THROUGH 14Z...BUT PATCHY FOG MAY LINGER IN
THIS AREA THROUGH THE MORNING.  OTHERWISE...VFR CONDITIONS WILL
PREVAIL ACROSS THE AREA 15Z SAT-03Z SUNDAY.  A COLD FRONT WILL
PLUNGE DOWN THE EAST SLOPES OF THE DIVIDE LATE SATURDAY MORNING
THROUGH SATURDAY AFTERNOON WITH SOME MTN OBSCURATIONS POSSIBLE ALONG
THE DIVIDE.  THIS FRONT MAY PUSH LOWER MVFR/IFR CIGS INTO VCNTY KRKS
AFTER 06Z SUNDAY.  FURTHER OUT FROM THE FRONT....LOWER MVFR/IFR CIGS
FROM EASTERN IDAHO MAY PUSH INTO THE FAR WEST...VCNTY KJAC-KAFO
AFTER 03Z SUNDAY.

&&

.FIRE WEATHER...

FIRE DANGER IS LOW FOR ALL AREAS...AND WILL REMAIN SO THROUGH NEXT
WEEK. MEASURABLE PRECIPITATION WILL NOT FALL ACROSS THE FORECAST
AREA UNTIL LATE SATURDAY INTO SUNDAY MORNING EAST OF THE DIVIDE.
FROM SUNDAY NIGHT THROUGH THE NEXT WORK WEEK...A SERIES OF
DISTURBANCES WILL RIDE THROUGH THE REGION...AFFECTING MAINLY THE
WESTERN AND NORTHERN DISPATCH ZONES. SATURDAY WILL SEE
IMPROVEMENT IN BOTH MIXING ABILITY AND DISPERSION...ESPECIALLY
EAST OF THE DIVIDE AND ACROSS THE SOUTHERN ZONES.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...LAVOIE
LONG TERM...BRANHAM
AVIATION...AEM
FIRE WEATHER...LAVOIE









000
FXUS65 KRIW 310654
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1154 PM MST FRI JAN 30 2015

UPDATE...ADDED 06Z AVIATION DISCUSSION.

.SHORT TERM...TONIGHT THROUGH SATURDAY (ISSUED AT 230 PM MST)

A WARM PACIFIC LOW OVER THE FOUR CORNERS AREA THIS
AFTERNOON...CONTINUES TO STREAM HIGH CLOUDS ACROSS THE COWBOY
STATE. LOW CLOUDS HAVE MADE THEIR WAY INTO THE I-80 CORRIDOR NEAR
KRKS...WHILE THE RAIN SHOWERS REMAIN WELL TO THE SOUTH IN NE
UT/NW CO. THESE SHOWERS WILL SLOWLY MAKE THEIR WAY NORTHWARD THIS
EVENING. TEMPERATURES ARE EXPECTED TO BE AT OR BELOW FREEZING BY
THIS TIME...PRODUCING LIGHT SNOW SHOWERS ACROSS SWEETWATER COUNTY.
ACCUMULATIONS ARE EXPECTED TO REMAIN LIGHT THROUGH MID MORNING
SATURDAY.

FOG CONTINUES TO HOLD ON OVER NORTHERN PORTIONS OF THE BIGHORN
BASIN...DESPITE THE CLOUDS ALOFT. FOG WILL BEGIN TO FILL IN
FURTHER SOUTH TOWARD KWRL DURING THE OVERNIGHT HOURS. FOG SHOULD
LIFT OUT BY MID MORNING...AS SKIES BEGIN TO CLEAR ACROSS THE AREA.

A COLD FRONT WILL BEGIN TO IMPACT NORTHERN PORTIONS LATE SATURDAY
AFTERNOON...BRINGING LOW CLOUDS AND GUSTY WINDS TO JOHNSON COUNTY.
LIGHT SNOW SHOWERS WILL BE POSSIBLE IN THE BIGHORNS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY NIGHT

THE SHORTWAVE MOVING THROUGH NORTHEASTERN WYOMING SATURDAY NIGHT
WILL HAVE SOME IMPACT OVER THE EASTERN PORTION OF THE FORECAST AREA
THROUGH SUNDAY MORNING. LIGHT SHOWER ACTIVITY IS EXPECTED.

BUILDING NORTHWEST FLOW THEN EXPECTED SUNDAY AFTERNOON AND EVENING
AS A RIDGE OF HIGH PRESSURE BUILDS OFF THE PACIFIC COAST. THIS
SYSTEM WILL BRING SOME MOISTURE INTO NORTHWESTERN WYOMING EARLY
MONDAY MORNING...MAINLY IMPACTING WESTERN AND NORTHERN WYOMING.

ANOTHER...MORE SIGNIFICANT PUSH OF MOISTURE WILL FOLLOW THAT SYSTEM
QUICKLY...WITH PRECIPITATION SPREADING INTO WESTERN WYOMING MONDAY
EVENING. ACTIVITY FROM THIS SYSTEM WILL LINGER THROUGH WEDNESDAY AS
ANOTHER PUSH COMES DOWN FROM THE NORTH AS WELL. THE ACTIVITY WILL
SPREAD TO INCLUDE MUCH OF THE FORECAST AREA. MODELS HAVE SOME
VARIATIONS ON THIS SYSTEM...WITH THE GFS REMAINING THE MOST
AGGRESSIVE MODEL. HOWEVER...ALL MODELS ARE IN FAIR AGREEMENT THAT
COVERAGE WILL INCREASE THROUGH WEDNESDAY MORNING.

CONDITIONS TO IMPROVE WEDNESDAY AFTERNOON AND EVENING. A BUILDING
RIDGE WILL HELP TO CLEAR OUT ACTIVITY...THOUGH SOME VERY LIGHT
ACTIVITY MAY REMAIN POSSIBLE ACROSS THE NORTHWEST THROUGH THURSDAY
AFTERNOON. DRY CONDITIONS EXPECTED BY FRIDAY MORNING...WHICH MAY NOT
LAST LONG.

&&

.AVIATION.../06Z ISSUANCE

AREAS OF FOG WILL OBSCURE TERRAIN ACROSS THE LOWER BIGHORN BASIN
THROUGH 14Z...VCNTY KGEY-KWRL.  A COLD FRONT WILL PUSH SOUTH ACROSS
NORTHERN WYOMING LATE SATURDAY MORNING...LIKELY SCOURING OUT ANY
LINGERING FOG.  HOWEVER...AREAS OF LOWER MVFR/IFR CIGS AND -SN WILL
FOLLOW THE FRONT INTO NORTHERN WYOMING AFTER 20Z...AND SOUTHWARD TO
NEAR A VCNTY KRIW-KCPR LINE BY 00Z SUNDAY.  AREAS OF LOWER MVFR/IFR
CIGS...LCL LIFR CIGS/FG WILL LIKELY REMAIN AGAINST THE EAST SLOPES
OF THE DIVIDE THROUGH 12Z SUNDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

AREAS OF IFR/MVFR CIGS AND -SN WILL GRADUALLY DECREASE ACROSS THE
INTERSTATE 80 CORRIDOR THROUGH 14Z...BUT PATCHY FOG MAY LINGER IN
THIS AREA THROUGH THE MORNING.  OTHERWISE...VFR CONDITIONS WILL
PREVAIL ACROSS THE AREA 15Z SAT-03Z SUNDAY.  A COLD FRONT WILL
PLUNGE DOWN THE EAST SLOPES OF THE DIVIDE LATE SATURDAY MORNING
THROUGH SATURDAY AFTERNOON WITH SOME MTN OBSCURATIONS POSSIBLE ALONG
THE DIVIDE.  THIS FRONT MAY PUSH LOWER MVFR/IFR CIGS INTO VCNTY KRKS
AFTER 06Z SUNDAY.  FURTHER OUT FROM THE FRONT....LOWER MVFR/IFR CIGS
FROM EASTERN IDAHO MAY PUSH INTO THE FAR WEST...VCNTY KJAC-KAFO
AFTER 03Z SUNDAY.

&&

.FIRE WEATHER...

FIRE DANGER IS LOW FOR ALL AREAS...AND WILL REMAIN SO THROUGH NEXT
WEEK. MEASURABLE PRECIPITATION WILL NOT FALL ACROSS THE FORECAST
AREA UNTIL LATE SATURDAY INTO SUNDAY MORNING EAST OF THE DIVIDE.
FROM SUNDAY NIGHT THROUGH THE NEXT WORK WEEK...A SERIES OF
DISTURBANCES WILL RIDE THROUGH THE REGION...AFFECTING MAINLY THE
WESTERN AND NORTHERN DISPATCH ZONES. SATURDAY WILL SEE
IMPROVEMENT IN BOTH MIXING ABILITY AND DISPERSION...ESPECIALLY
EAST OF THE DIVIDE AND ACROSS THE SOUTHERN ZONES.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...LAVOIE
LONG TERM...BRANHAM
AVIATION...AEM
FIRE WEATHER...LAVOIE










000
FXUS65 KCYS 310553
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1053 PM MST FRI JAN 30 2015

.UPDATE...
ISSUED AT 907 PM MST FRI JAN 30 2015

UPPER LEVEL LOW SPINNING OVER THE SOUTHWEST CONUS CONTINUES TO
PUSH HIGH CLOUDS INTO THE FORECAST AREA. SOME LIGHT SNOW HAS ALSO
MADE ITS WAY INTO THE SNOWY AND SIERRA MADRE RANGES. ACCUMLUATIONS
IN THE MOUNTAINS WILL BE MINIMAL WITH MAYBE AN INCH OR TWO
POSSIBLE. OTHERWISE LITTLE TO NO SNOW EXPECTED OVER THE FORECAST
AREA TONIGHT WITH NOT MUCH MORE THAN FLURRIES NEAR THE COLORADO/
WYOMING BORDER OUTSIDE OF THE MOUNTAINS. PLACES LIKE BAGS AND DIX
COULD SEE A DUSTING OF SNOW BUT THAT IS ABOUT IT. NO UPDATES
NEEDED AS TONIGHTS FORECAST IS ON TRACK.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 250 PM MST FRI JAN 30 2015

MODELS IN GOOD AGREEMENT THROUGH THIS WEEKEND SHOWING THE OVERALL
WEATHER PATTERN TRANSITIONING TOWARDS NORTH TO NORTHWEST FLOW AND
COLDER TEMPERATURES. CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE
BROAD UPPER LEVEL LOW...WHICH IS RESPONSIBLE FOR BREAKING DOWN THE
STRONG UPPER LEVEL RIDGE ALONG THE WEST COAST EARLIER THIS
WEEK...OVER SOUTHERN CALIFORNIA THIS AFTERNOON. THIS LOW WILL
INITIALLY DRIFT EASTWARD TONIGHT...HOWEVER...SATELLITE IMAGERY
SHOWS A SHORTWAVE MOVING ACROSS BRITISH COLUMBIA AND DIGGING
SOUTHEAST INTO MONTANA LATE TONIGHT AND INTO EARLY SATURDAY. THIS
FEATURE WILL BE ASSOCIATED WITH A COLD FRONT WITH A MODIFIED
ARCTIC AIRMASS PUSHING INTO THE NORTHERN PLAINS. THIS WILL RESULT
IN THE BROAD UPPER LEVEL LOW OVER THE DESERT SOUTHWEST TO BEGIN
DIGGING SOUTH AND SOUTHEAST INTO MEXICO ON SATURDAY...MAINLY
MISSING MOST OF SOUTHEAST WYOMING AND WESTERN NEBRASKA. CAN NOT
RULE OUT SOME LIGHT SNOW ALONG AND SOUTH OF I80 HOWEVER...SO KEPT
POP BETWEEN 15 TO 30 PERCENT FROM RAWLINS TO CHEYENNE TONIGHT AND
EARLY SATURDAY. THE HIGH PLAINS MAY GET CLIPPED BY THE REAR
ENTRANCE REGION OF A STRENGTHENING JET ALOFT...BUT PRECIPITATION
WILL LIKELY BE MIXED WITH RAIN DURING THE DAY. REMOVED THE
POTENTIAL FOR FOG TONIGHT AND EARLY SATURDAY SINCE THE UPPER LEVEL
LOW WILL BE TOO FAR SOUTH AND LLVL WINDS WILL BE LIGHT NORTHERLY.
THE BEST CHANCE FOR SOME LOWER VISIBILITIES WILL BE THE CHEYENNE
RIDGE FROM KIMBALL TO SIDNEY...AND MAYBE THE LOWER ELEVATIONS OF
CARBON COUNTY IF WINDS BECOME LIGHT FOR A TIME BEFORE SHIFTING
INTO THE NORTHEAST. IN ADDITION...MID TO HIGH CLOUDS WILL BE
PROBLEMATIC FOR LLVL FOG DEVELOPMENT...SO MAY JUST SEE LOW CLOUDS
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. KEPT LOW
TEMPERATURES ABOVE MODEL GUIDANCE DUE TO THIS CLOUD COVER.
TEMPERATURES WILL BE NEAR NORMAL FOR SATURDAY...WITH HIGHS IN THE
UPPER 30S TO MID 40S. WITH THE EXCEPTION OF THE EXITING JET
ALOFT...WEATHER SHOULD BE RELATIVELY DRY OUTSIDE THE MOUNTAINS
WITH MINIMAL SNOW ACCUMULATIONS.

BY SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE COLD FRONT PUSHES
ACROSS THE AREA WITH THE COLDEST AIR ACROSS THE HIGH PLAINS. THIS
MAY BE THE BEST CHANCE FOR MOST AREAS TO SEE A LITTLE BIT OF LIGHT
SNOW ACCORDING TO THE SHORT TERM ENSEMBLES. INCREASED POP BETWEEN
20 TO 35 PERCENT ACROSS MOST OF THE AREA...ESPECIALLY ALONG AND
EAST OF THE LARAMIE RANGE. TEMPERATURES WILL BE BELOW NORMAL ON
SUNDAY BUT DRIER AIR WILL PUSH INTO THE AREA DURING THE AFTERNOON
AS THE TROUGH QUICKLY DIGS SOUTHEAST ACROSS THE CENTRAL PLAINS.
MODELS SHOW THE POTENTIAL FOR STRONG WINDS ACROSS SOUTHEAST
WYOMING BY LATE SUNDAY NIGHT AS A LLVL GRADIENT INCREASES ALONG
THE LARAMIE RANGE.

.LONG TERM...(MONDAY THROUGH NEXT FRIDAY)
ISSUED AT 250 PM MST FRI JAN 30 2015

MONDAY WILL START OUT BREEZY WITH WINDS ACROSS THE NORMALLY WINDIER
LOCATIONS ALONG AND WEST OF THE LARAMIE RANGE GUSTING 35 TO 45 MPH
OUT OF THE WEST IN THE MORNING AS A SHORTWAVE MOVES SOUTHEAST ACROSS
WYOMING.  THE SHORTWAVE MOVES QUICKLY OUT TO THE EAST BY MONDAY
AFTERNOON...BUT WITH THE MID/UPPER FLOW PERSISTING OUT OF THE
NORTHWEST SHOULD SEE ADDITIONAL WEAK SHORTWAVES MOVE DOWN ACROSS THE
AREA TUESDAY THROUGH THURSDAY.  WE MAY GET A PERIOD AGAIN TUESDAY
WITH SLIGHTLY INCREASED WINDS GUSTING 30-40 MPH.  KEPT CHANCES OF
SNOW GOING IN THE HIGHER TERRAIN ACROSS PORTIONS OF CARBON...ALBANY
AND WESTERN LARAMIE COUNTIES MONDAY INTO TUESDAY...BUT SNOWFALL
TOTALS SHOULD REMAIN FAIRLY LIGHT.  BY TUESDAY NIGHT...A FAIRLY
ROBUST UPPER DISTURBANCE WILL CARVE OUT AN UPPER TROUGH OVER THE
DAKOTAS AND MINNESOTA...GIVING THE ARCTIC AIRMASS LOCKED TO OUR
NORTH A QUICK SHOVE SOUTHWARD BY WEDNESDAY MORNING.  THE COLD FRONT
ON THE WESTERN EDGE OF THAT AIRMASS WILL MOVE INTO THE EASTERN HALF
OF OUR FORECAST AREA TUESDAY NIGHT BEFORE HANGING UP IN THE
MOUNTAINS.  SOME OF THE GUIDANCE CAME UP ON LOW TEMPERATURES
WEDNESDAY MORNING CONTRARY TO THE PHYSICAL GUIDANCE OF THE GFS AND
ECMWF WHICH SHOWS SHALLOW COLDER AIRMASS WORKING IN FROM THE
NORTHEAST.  FOR THIS PACKAGE WE OPTED TO STAY CLOSER TO OUR PREVIOUS
MIDNIGHT SHIFT FORECAST UNTIL GUIDANCE TRENDS BECOME MORE
CONSISTENT...KEEPING LOWS IN THE TEENS EAST OF THE LARAMIE RANGE
WEDNESDAY AND THURSDAY MORNINGS. WE ALSO KEPT SLIGHT CHANCE TO
CHANCE POPS FOR SHOWERS (SNOW WEST AND A MIX EAST) GOING ACROSS THE
AREA ON WEDNESDAY IN ASSOCIATION WITH THE SURFACE BOUNDARY AND A
PASSING UPPER DISTURBANCE.   LOOKING FARTHER OUT...UPPER RIDGING
WILL WORK IN FROM THE WEST THURSDAY INTO FRIDAY.  WE SHOULD SEE
DECREASED POPS AND A BIT OF A WARMUP LATE THURSDAY INTO FRIDAY WITH
TEMPERATURES OUT WEST ON FRIDAY IN THE 40S (EXCEPT 30S IN THE
MOUNTAINS) AND 50S OUT EAST ON THE PLAINS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1042 PM MST FRI JAN 30 2015

MAIN AVIATION CONCERN WILL BE ALONG AND NEAR THE COLORADO AND
WYOMING BORDER TONIGHT AS AN UPPER LEVEL LOW SPINS OVER THE
SOUTHWEST CONUS. SOME LIGHT SNOW IS EXPECTED IN THESE AREAS
TONIGHT BUT IT WILL BE LIGHT WITH MAINLY MVFR AND LOCALLY IFR.
THE SNOWY AND SIERRA MADRE MOUNTAINS MAY BE OBSCURED DUE TO THE
LIGHT SNOW.

WINDS WILL BE LIGHT THROUGH SATURDAY AFTERNOON BUT A COLD FRONT
WILL MOVE ACROSS THE PLAINS SATURDAY NIGHT WITH GUSTY NORTHWEST
WINDS DEVELOPING. THERE ALSO COULD BE A PERIOD OF LIGHT SNOW INTO
SOUTHERN PORTIONS OF THE NEBRASKA PANHANDLE LATE SATURDAY
AFTERNOON AND EVENING AHEAD OF THE COLD FRONT. IFR POSSIBLE WITH
THE FALLING SNOW WHICH COULD AFFECT KAIA AND KSNY. THE MAIN AREA
OF SNOW WILL SET UP EAST OF THE PANHANDLE INTO CENTRAL NEBRASKA.

&&

.FIRE WEATHER...
ISSUED AT 150 PM MST FRI JAN 30 2015

NO FIRE WEATHER CONCERNS ANTICIPATED. RECENT MILD SPRING-LIKE
CONDITIONS WILL END BY THIS WEEKEND AS AN ARCTIC COLD FRONT MOVES
SOUTHWARD ACROSS THE AREA BY SATURDAY. COOL TEMPERATURES...HIGH
RELATIVE HUMIDITIES...AND A CHANCE OF LIGHT PRECIPITATION ARE
EXPECTED INTO EARLY NEXT WEEK. ANOTHER STRONG COLD FRONT MAY
IMPACT THE REGION ON WEDNESDAY...BRINGING WIDESPREAD SNOWFALL TO
SOUTHEAST WYOMING AND PORTIONS OF WESTERN NEBRASKA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...TJT
LONG TERM...JG
AVIATION...SML
FIRE WEATHER...TJT




000
FXUS65 KCYS 310553
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1053 PM MST FRI JAN 30 2015

.UPDATE...
ISSUED AT 907 PM MST FRI JAN 30 2015

UPPER LEVEL LOW SPINNING OVER THE SOUTHWEST CONUS CONTINUES TO
PUSH HIGH CLOUDS INTO THE FORECAST AREA. SOME LIGHT SNOW HAS ALSO
MADE ITS WAY INTO THE SNOWY AND SIERRA MADRE RANGES. ACCUMLUATIONS
IN THE MOUNTAINS WILL BE MINIMAL WITH MAYBE AN INCH OR TWO
POSSIBLE. OTHERWISE LITTLE TO NO SNOW EXPECTED OVER THE FORECAST
AREA TONIGHT WITH NOT MUCH MORE THAN FLURRIES NEAR THE COLORADO/
WYOMING BORDER OUTSIDE OF THE MOUNTAINS. PLACES LIKE BAGS AND DIX
COULD SEE A DUSTING OF SNOW BUT THAT IS ABOUT IT. NO UPDATES
NEEDED AS TONIGHTS FORECAST IS ON TRACK.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 250 PM MST FRI JAN 30 2015

MODELS IN GOOD AGREEMENT THROUGH THIS WEEKEND SHOWING THE OVERALL
WEATHER PATTERN TRANSITIONING TOWARDS NORTH TO NORTHWEST FLOW AND
COLDER TEMPERATURES. CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE
BROAD UPPER LEVEL LOW...WHICH IS RESPONSIBLE FOR BREAKING DOWN THE
STRONG UPPER LEVEL RIDGE ALONG THE WEST COAST EARLIER THIS
WEEK...OVER SOUTHERN CALIFORNIA THIS AFTERNOON. THIS LOW WILL
INITIALLY DRIFT EASTWARD TONIGHT...HOWEVER...SATELLITE IMAGERY
SHOWS A SHORTWAVE MOVING ACROSS BRITISH COLUMBIA AND DIGGING
SOUTHEAST INTO MONTANA LATE TONIGHT AND INTO EARLY SATURDAY. THIS
FEATURE WILL BE ASSOCIATED WITH A COLD FRONT WITH A MODIFIED
ARCTIC AIRMASS PUSHING INTO THE NORTHERN PLAINS. THIS WILL RESULT
IN THE BROAD UPPER LEVEL LOW OVER THE DESERT SOUTHWEST TO BEGIN
DIGGING SOUTH AND SOUTHEAST INTO MEXICO ON SATURDAY...MAINLY
MISSING MOST OF SOUTHEAST WYOMING AND WESTERN NEBRASKA. CAN NOT
RULE OUT SOME LIGHT SNOW ALONG AND SOUTH OF I80 HOWEVER...SO KEPT
POP BETWEEN 15 TO 30 PERCENT FROM RAWLINS TO CHEYENNE TONIGHT AND
EARLY SATURDAY. THE HIGH PLAINS MAY GET CLIPPED BY THE REAR
ENTRANCE REGION OF A STRENGTHENING JET ALOFT...BUT PRECIPITATION
WILL LIKELY BE MIXED WITH RAIN DURING THE DAY. REMOVED THE
POTENTIAL FOR FOG TONIGHT AND EARLY SATURDAY SINCE THE UPPER LEVEL
LOW WILL BE TOO FAR SOUTH AND LLVL WINDS WILL BE LIGHT NORTHERLY.
THE BEST CHANCE FOR SOME LOWER VISIBILITIES WILL BE THE CHEYENNE
RIDGE FROM KIMBALL TO SIDNEY...AND MAYBE THE LOWER ELEVATIONS OF
CARBON COUNTY IF WINDS BECOME LIGHT FOR A TIME BEFORE SHIFTING
INTO THE NORTHEAST. IN ADDITION...MID TO HIGH CLOUDS WILL BE
PROBLEMATIC FOR LLVL FOG DEVELOPMENT...SO MAY JUST SEE LOW CLOUDS
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. KEPT LOW
TEMPERATURES ABOVE MODEL GUIDANCE DUE TO THIS CLOUD COVER.
TEMPERATURES WILL BE NEAR NORMAL FOR SATURDAY...WITH HIGHS IN THE
UPPER 30S TO MID 40S. WITH THE EXCEPTION OF THE EXITING JET
ALOFT...WEATHER SHOULD BE RELATIVELY DRY OUTSIDE THE MOUNTAINS
WITH MINIMAL SNOW ACCUMULATIONS.

BY SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE COLD FRONT PUSHES
ACROSS THE AREA WITH THE COLDEST AIR ACROSS THE HIGH PLAINS. THIS
MAY BE THE BEST CHANCE FOR MOST AREAS TO SEE A LITTLE BIT OF LIGHT
SNOW ACCORDING TO THE SHORT TERM ENSEMBLES. INCREASED POP BETWEEN
20 TO 35 PERCENT ACROSS MOST OF THE AREA...ESPECIALLY ALONG AND
EAST OF THE LARAMIE RANGE. TEMPERATURES WILL BE BELOW NORMAL ON
SUNDAY BUT DRIER AIR WILL PUSH INTO THE AREA DURING THE AFTERNOON
AS THE TROUGH QUICKLY DIGS SOUTHEAST ACROSS THE CENTRAL PLAINS.
MODELS SHOW THE POTENTIAL FOR STRONG WINDS ACROSS SOUTHEAST
WYOMING BY LATE SUNDAY NIGHT AS A LLVL GRADIENT INCREASES ALONG
THE LARAMIE RANGE.

.LONG TERM...(MONDAY THROUGH NEXT FRIDAY)
ISSUED AT 250 PM MST FRI JAN 30 2015

MONDAY WILL START OUT BREEZY WITH WINDS ACROSS THE NORMALLY WINDIER
LOCATIONS ALONG AND WEST OF THE LARAMIE RANGE GUSTING 35 TO 45 MPH
OUT OF THE WEST IN THE MORNING AS A SHORTWAVE MOVES SOUTHEAST ACROSS
WYOMING.  THE SHORTWAVE MOVES QUICKLY OUT TO THE EAST BY MONDAY
AFTERNOON...BUT WITH THE MID/UPPER FLOW PERSISTING OUT OF THE
NORTHWEST SHOULD SEE ADDITIONAL WEAK SHORTWAVES MOVE DOWN ACROSS THE
AREA TUESDAY THROUGH THURSDAY.  WE MAY GET A PERIOD AGAIN TUESDAY
WITH SLIGHTLY INCREASED WINDS GUSTING 30-40 MPH.  KEPT CHANCES OF
SNOW GOING IN THE HIGHER TERRAIN ACROSS PORTIONS OF CARBON...ALBANY
AND WESTERN LARAMIE COUNTIES MONDAY INTO TUESDAY...BUT SNOWFALL
TOTALS SHOULD REMAIN FAIRLY LIGHT.  BY TUESDAY NIGHT...A FAIRLY
ROBUST UPPER DISTURBANCE WILL CARVE OUT AN UPPER TROUGH OVER THE
DAKOTAS AND MINNESOTA...GIVING THE ARCTIC AIRMASS LOCKED TO OUR
NORTH A QUICK SHOVE SOUTHWARD BY WEDNESDAY MORNING.  THE COLD FRONT
ON THE WESTERN EDGE OF THAT AIRMASS WILL MOVE INTO THE EASTERN HALF
OF OUR FORECAST AREA TUESDAY NIGHT BEFORE HANGING UP IN THE
MOUNTAINS.  SOME OF THE GUIDANCE CAME UP ON LOW TEMPERATURES
WEDNESDAY MORNING CONTRARY TO THE PHYSICAL GUIDANCE OF THE GFS AND
ECMWF WHICH SHOWS SHALLOW COLDER AIRMASS WORKING IN FROM THE
NORTHEAST.  FOR THIS PACKAGE WE OPTED TO STAY CLOSER TO OUR PREVIOUS
MIDNIGHT SHIFT FORECAST UNTIL GUIDANCE TRENDS BECOME MORE
CONSISTENT...KEEPING LOWS IN THE TEENS EAST OF THE LARAMIE RANGE
WEDNESDAY AND THURSDAY MORNINGS. WE ALSO KEPT SLIGHT CHANCE TO
CHANCE POPS FOR SHOWERS (SNOW WEST AND A MIX EAST) GOING ACROSS THE
AREA ON WEDNESDAY IN ASSOCIATION WITH THE SURFACE BOUNDARY AND A
PASSING UPPER DISTURBANCE.   LOOKING FARTHER OUT...UPPER RIDGING
WILL WORK IN FROM THE WEST THURSDAY INTO FRIDAY.  WE SHOULD SEE
DECREASED POPS AND A BIT OF A WARMUP LATE THURSDAY INTO FRIDAY WITH
TEMPERATURES OUT WEST ON FRIDAY IN THE 40S (EXCEPT 30S IN THE
MOUNTAINS) AND 50S OUT EAST ON THE PLAINS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1042 PM MST FRI JAN 30 2015

MAIN AVIATION CONCERN WILL BE ALONG AND NEAR THE COLORADO AND
WYOMING BORDER TONIGHT AS AN UPPER LEVEL LOW SPINS OVER THE
SOUTHWEST CONUS. SOME LIGHT SNOW IS EXPECTED IN THESE AREAS
TONIGHT BUT IT WILL BE LIGHT WITH MAINLY MVFR AND LOCALLY IFR.
THE SNOWY AND SIERRA MADRE MOUNTAINS MAY BE OBSCURED DUE TO THE
LIGHT SNOW.

WINDS WILL BE LIGHT THROUGH SATURDAY AFTERNOON BUT A COLD FRONT
WILL MOVE ACROSS THE PLAINS SATURDAY NIGHT WITH GUSTY NORTHWEST
WINDS DEVELOPING. THERE ALSO COULD BE A PERIOD OF LIGHT SNOW INTO
SOUTHERN PORTIONS OF THE NEBRASKA PANHANDLE LATE SATURDAY
AFTERNOON AND EVENING AHEAD OF THE COLD FRONT. IFR POSSIBLE WITH
THE FALLING SNOW WHICH COULD AFFECT KAIA AND KSNY. THE MAIN AREA
OF SNOW WILL SET UP EAST OF THE PANHANDLE INTO CENTRAL NEBRASKA.

&&

.FIRE WEATHER...
ISSUED AT 150 PM MST FRI JAN 30 2015

NO FIRE WEATHER CONCERNS ANTICIPATED. RECENT MILD SPRING-LIKE
CONDITIONS WILL END BY THIS WEEKEND AS AN ARCTIC COLD FRONT MOVES
SOUTHWARD ACROSS THE AREA BY SATURDAY. COOL TEMPERATURES...HIGH
RELATIVE HUMIDITIES...AND A CHANCE OF LIGHT PRECIPITATION ARE
EXPECTED INTO EARLY NEXT WEEK. ANOTHER STRONG COLD FRONT MAY
IMPACT THE REGION ON WEDNESDAY...BRINGING WIDESPREAD SNOWFALL TO
SOUTHEAST WYOMING AND PORTIONS OF WESTERN NEBRASKA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...TJT
LONG TERM...JG
AVIATION...SML
FIRE WEATHER...TJT




000
FXUS65 KCYS 310553
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1053 PM MST FRI JAN 30 2015

.UPDATE...
ISSUED AT 907 PM MST FRI JAN 30 2015

UPPER LEVEL LOW SPINNING OVER THE SOUTHWEST CONUS CONTINUES TO
PUSH HIGH CLOUDS INTO THE FORECAST AREA. SOME LIGHT SNOW HAS ALSO
MADE ITS WAY INTO THE SNOWY AND SIERRA MADRE RANGES. ACCUMLUATIONS
IN THE MOUNTAINS WILL BE MINIMAL WITH MAYBE AN INCH OR TWO
POSSIBLE. OTHERWISE LITTLE TO NO SNOW EXPECTED OVER THE FORECAST
AREA TONIGHT WITH NOT MUCH MORE THAN FLURRIES NEAR THE COLORADO/
WYOMING BORDER OUTSIDE OF THE MOUNTAINS. PLACES LIKE BAGS AND DIX
COULD SEE A DUSTING OF SNOW BUT THAT IS ABOUT IT. NO UPDATES
NEEDED AS TONIGHTS FORECAST IS ON TRACK.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 250 PM MST FRI JAN 30 2015

MODELS IN GOOD AGREEMENT THROUGH THIS WEEKEND SHOWING THE OVERALL
WEATHER PATTERN TRANSITIONING TOWARDS NORTH TO NORTHWEST FLOW AND
COLDER TEMPERATURES. CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE
BROAD UPPER LEVEL LOW...WHICH IS RESPONSIBLE FOR BREAKING DOWN THE
STRONG UPPER LEVEL RIDGE ALONG THE WEST COAST EARLIER THIS
WEEK...OVER SOUTHERN CALIFORNIA THIS AFTERNOON. THIS LOW WILL
INITIALLY DRIFT EASTWARD TONIGHT...HOWEVER...SATELLITE IMAGERY
SHOWS A SHORTWAVE MOVING ACROSS BRITISH COLUMBIA AND DIGGING
SOUTHEAST INTO MONTANA LATE TONIGHT AND INTO EARLY SATURDAY. THIS
FEATURE WILL BE ASSOCIATED WITH A COLD FRONT WITH A MODIFIED
ARCTIC AIRMASS PUSHING INTO THE NORTHERN PLAINS. THIS WILL RESULT
IN THE BROAD UPPER LEVEL LOW OVER THE DESERT SOUTHWEST TO BEGIN
DIGGING SOUTH AND SOUTHEAST INTO MEXICO ON SATURDAY...MAINLY
MISSING MOST OF SOUTHEAST WYOMING AND WESTERN NEBRASKA. CAN NOT
RULE OUT SOME LIGHT SNOW ALONG AND SOUTH OF I80 HOWEVER...SO KEPT
POP BETWEEN 15 TO 30 PERCENT FROM RAWLINS TO CHEYENNE TONIGHT AND
EARLY SATURDAY. THE HIGH PLAINS MAY GET CLIPPED BY THE REAR
ENTRANCE REGION OF A STRENGTHENING JET ALOFT...BUT PRECIPITATION
WILL LIKELY BE MIXED WITH RAIN DURING THE DAY. REMOVED THE
POTENTIAL FOR FOG TONIGHT AND EARLY SATURDAY SINCE THE UPPER LEVEL
LOW WILL BE TOO FAR SOUTH AND LLVL WINDS WILL BE LIGHT NORTHERLY.
THE BEST CHANCE FOR SOME LOWER VISIBILITIES WILL BE THE CHEYENNE
RIDGE FROM KIMBALL TO SIDNEY...AND MAYBE THE LOWER ELEVATIONS OF
CARBON COUNTY IF WINDS BECOME LIGHT FOR A TIME BEFORE SHIFTING
INTO THE NORTHEAST. IN ADDITION...MID TO HIGH CLOUDS WILL BE
PROBLEMATIC FOR LLVL FOG DEVELOPMENT...SO MAY JUST SEE LOW CLOUDS
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. KEPT LOW
TEMPERATURES ABOVE MODEL GUIDANCE DUE TO THIS CLOUD COVER.
TEMPERATURES WILL BE NEAR NORMAL FOR SATURDAY...WITH HIGHS IN THE
UPPER 30S TO MID 40S. WITH THE EXCEPTION OF THE EXITING JET
ALOFT...WEATHER SHOULD BE RELATIVELY DRY OUTSIDE THE MOUNTAINS
WITH MINIMAL SNOW ACCUMULATIONS.

BY SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE COLD FRONT PUSHES
ACROSS THE AREA WITH THE COLDEST AIR ACROSS THE HIGH PLAINS. THIS
MAY BE THE BEST CHANCE FOR MOST AREAS TO SEE A LITTLE BIT OF LIGHT
SNOW ACCORDING TO THE SHORT TERM ENSEMBLES. INCREASED POP BETWEEN
20 TO 35 PERCENT ACROSS MOST OF THE AREA...ESPECIALLY ALONG AND
EAST OF THE LARAMIE RANGE. TEMPERATURES WILL BE BELOW NORMAL ON
SUNDAY BUT DRIER AIR WILL PUSH INTO THE AREA DURING THE AFTERNOON
AS THE TROUGH QUICKLY DIGS SOUTHEAST ACROSS THE CENTRAL PLAINS.
MODELS SHOW THE POTENTIAL FOR STRONG WINDS ACROSS SOUTHEAST
WYOMING BY LATE SUNDAY NIGHT AS A LLVL GRADIENT INCREASES ALONG
THE LARAMIE RANGE.

.LONG TERM...(MONDAY THROUGH NEXT FRIDAY)
ISSUED AT 250 PM MST FRI JAN 30 2015

MONDAY WILL START OUT BREEZY WITH WINDS ACROSS THE NORMALLY WINDIER
LOCATIONS ALONG AND WEST OF THE LARAMIE RANGE GUSTING 35 TO 45 MPH
OUT OF THE WEST IN THE MORNING AS A SHORTWAVE MOVES SOUTHEAST ACROSS
WYOMING.  THE SHORTWAVE MOVES QUICKLY OUT TO THE EAST BY MONDAY
AFTERNOON...BUT WITH THE MID/UPPER FLOW PERSISTING OUT OF THE
NORTHWEST SHOULD SEE ADDITIONAL WEAK SHORTWAVES MOVE DOWN ACROSS THE
AREA TUESDAY THROUGH THURSDAY.  WE MAY GET A PERIOD AGAIN TUESDAY
WITH SLIGHTLY INCREASED WINDS GUSTING 30-40 MPH.  KEPT CHANCES OF
SNOW GOING IN THE HIGHER TERRAIN ACROSS PORTIONS OF CARBON...ALBANY
AND WESTERN LARAMIE COUNTIES MONDAY INTO TUESDAY...BUT SNOWFALL
TOTALS SHOULD REMAIN FAIRLY LIGHT.  BY TUESDAY NIGHT...A FAIRLY
ROBUST UPPER DISTURBANCE WILL CARVE OUT AN UPPER TROUGH OVER THE
DAKOTAS AND MINNESOTA...GIVING THE ARCTIC AIRMASS LOCKED TO OUR
NORTH A QUICK SHOVE SOUTHWARD BY WEDNESDAY MORNING.  THE COLD FRONT
ON THE WESTERN EDGE OF THAT AIRMASS WILL MOVE INTO THE EASTERN HALF
OF OUR FORECAST AREA TUESDAY NIGHT BEFORE HANGING UP IN THE
MOUNTAINS.  SOME OF THE GUIDANCE CAME UP ON LOW TEMPERATURES
WEDNESDAY MORNING CONTRARY TO THE PHYSICAL GUIDANCE OF THE GFS AND
ECMWF WHICH SHOWS SHALLOW COLDER AIRMASS WORKING IN FROM THE
NORTHEAST.  FOR THIS PACKAGE WE OPTED TO STAY CLOSER TO OUR PREVIOUS
MIDNIGHT SHIFT FORECAST UNTIL GUIDANCE TRENDS BECOME MORE
CONSISTENT...KEEPING LOWS IN THE TEENS EAST OF THE LARAMIE RANGE
WEDNESDAY AND THURSDAY MORNINGS. WE ALSO KEPT SLIGHT CHANCE TO
CHANCE POPS FOR SHOWERS (SNOW WEST AND A MIX EAST) GOING ACROSS THE
AREA ON WEDNESDAY IN ASSOCIATION WITH THE SURFACE BOUNDARY AND A
PASSING UPPER DISTURBANCE.   LOOKING FARTHER OUT...UPPER RIDGING
WILL WORK IN FROM THE WEST THURSDAY INTO FRIDAY.  WE SHOULD SEE
DECREASED POPS AND A BIT OF A WARMUP LATE THURSDAY INTO FRIDAY WITH
TEMPERATURES OUT WEST ON FRIDAY IN THE 40S (EXCEPT 30S IN THE
MOUNTAINS) AND 50S OUT EAST ON THE PLAINS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1042 PM MST FRI JAN 30 2015

MAIN AVIATION CONCERN WILL BE ALONG AND NEAR THE COLORADO AND
WYOMING BORDER TONIGHT AS AN UPPER LEVEL LOW SPINS OVER THE
SOUTHWEST CONUS. SOME LIGHT SNOW IS EXPECTED IN THESE AREAS
TONIGHT BUT IT WILL BE LIGHT WITH MAINLY MVFR AND LOCALLY IFR.
THE SNOWY AND SIERRA MADRE MOUNTAINS MAY BE OBSCURED DUE TO THE
LIGHT SNOW.

WINDS WILL BE LIGHT THROUGH SATURDAY AFTERNOON BUT A COLD FRONT
WILL MOVE ACROSS THE PLAINS SATURDAY NIGHT WITH GUSTY NORTHWEST
WINDS DEVELOPING. THERE ALSO COULD BE A PERIOD OF LIGHT SNOW INTO
SOUTHERN PORTIONS OF THE NEBRASKA PANHANDLE LATE SATURDAY
AFTERNOON AND EVENING AHEAD OF THE COLD FRONT. IFR POSSIBLE WITH
THE FALLING SNOW WHICH COULD AFFECT KAIA AND KSNY. THE MAIN AREA
OF SNOW WILL SET UP EAST OF THE PANHANDLE INTO CENTRAL NEBRASKA.

&&

.FIRE WEATHER...
ISSUED AT 150 PM MST FRI JAN 30 2015

NO FIRE WEATHER CONCERNS ANTICIPATED. RECENT MILD SPRING-LIKE
CONDITIONS WILL END BY THIS WEEKEND AS AN ARCTIC COLD FRONT MOVES
SOUTHWARD ACROSS THE AREA BY SATURDAY. COOL TEMPERATURES...HIGH
RELATIVE HUMIDITIES...AND A CHANCE OF LIGHT PRECIPITATION ARE
EXPECTED INTO EARLY NEXT WEEK. ANOTHER STRONG COLD FRONT MAY
IMPACT THE REGION ON WEDNESDAY...BRINGING WIDESPREAD SNOWFALL TO
SOUTHEAST WYOMING AND PORTIONS OF WESTERN NEBRASKA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...TJT
LONG TERM...JG
AVIATION...SML
FIRE WEATHER...TJT




000
FXUS65 KCYS 310553
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1053 PM MST FRI JAN 30 2015

.UPDATE...
ISSUED AT 907 PM MST FRI JAN 30 2015

UPPER LEVEL LOW SPINNING OVER THE SOUTHWEST CONUS CONTINUES TO
PUSH HIGH CLOUDS INTO THE FORECAST AREA. SOME LIGHT SNOW HAS ALSO
MADE ITS WAY INTO THE SNOWY AND SIERRA MADRE RANGES. ACCUMLUATIONS
IN THE MOUNTAINS WILL BE MINIMAL WITH MAYBE AN INCH OR TWO
POSSIBLE. OTHERWISE LITTLE TO NO SNOW EXPECTED OVER THE FORECAST
AREA TONIGHT WITH NOT MUCH MORE THAN FLURRIES NEAR THE COLORADO/
WYOMING BORDER OUTSIDE OF THE MOUNTAINS. PLACES LIKE BAGS AND DIX
COULD SEE A DUSTING OF SNOW BUT THAT IS ABOUT IT. NO UPDATES
NEEDED AS TONIGHTS FORECAST IS ON TRACK.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 250 PM MST FRI JAN 30 2015

MODELS IN GOOD AGREEMENT THROUGH THIS WEEKEND SHOWING THE OVERALL
WEATHER PATTERN TRANSITIONING TOWARDS NORTH TO NORTHWEST FLOW AND
COLDER TEMPERATURES. CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE
BROAD UPPER LEVEL LOW...WHICH IS RESPONSIBLE FOR BREAKING DOWN THE
STRONG UPPER LEVEL RIDGE ALONG THE WEST COAST EARLIER THIS
WEEK...OVER SOUTHERN CALIFORNIA THIS AFTERNOON. THIS LOW WILL
INITIALLY DRIFT EASTWARD TONIGHT...HOWEVER...SATELLITE IMAGERY
SHOWS A SHORTWAVE MOVING ACROSS BRITISH COLUMBIA AND DIGGING
SOUTHEAST INTO MONTANA LATE TONIGHT AND INTO EARLY SATURDAY. THIS
FEATURE WILL BE ASSOCIATED WITH A COLD FRONT WITH A MODIFIED
ARCTIC AIRMASS PUSHING INTO THE NORTHERN PLAINS. THIS WILL RESULT
IN THE BROAD UPPER LEVEL LOW OVER THE DESERT SOUTHWEST TO BEGIN
DIGGING SOUTH AND SOUTHEAST INTO MEXICO ON SATURDAY...MAINLY
MISSING MOST OF SOUTHEAST WYOMING AND WESTERN NEBRASKA. CAN NOT
RULE OUT SOME LIGHT SNOW ALONG AND SOUTH OF I80 HOWEVER...SO KEPT
POP BETWEEN 15 TO 30 PERCENT FROM RAWLINS TO CHEYENNE TONIGHT AND
EARLY SATURDAY. THE HIGH PLAINS MAY GET CLIPPED BY THE REAR
ENTRANCE REGION OF A STRENGTHENING JET ALOFT...BUT PRECIPITATION
WILL LIKELY BE MIXED WITH RAIN DURING THE DAY. REMOVED THE
POTENTIAL FOR FOG TONIGHT AND EARLY SATURDAY SINCE THE UPPER LEVEL
LOW WILL BE TOO FAR SOUTH AND LLVL WINDS WILL BE LIGHT NORTHERLY.
THE BEST CHANCE FOR SOME LOWER VISIBILITIES WILL BE THE CHEYENNE
RIDGE FROM KIMBALL TO SIDNEY...AND MAYBE THE LOWER ELEVATIONS OF
CARBON COUNTY IF WINDS BECOME LIGHT FOR A TIME BEFORE SHIFTING
INTO THE NORTHEAST. IN ADDITION...MID TO HIGH CLOUDS WILL BE
PROBLEMATIC FOR LLVL FOG DEVELOPMENT...SO MAY JUST SEE LOW CLOUDS
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. KEPT LOW
TEMPERATURES ABOVE MODEL GUIDANCE DUE TO THIS CLOUD COVER.
TEMPERATURES WILL BE NEAR NORMAL FOR SATURDAY...WITH HIGHS IN THE
UPPER 30S TO MID 40S. WITH THE EXCEPTION OF THE EXITING JET
ALOFT...WEATHER SHOULD BE RELATIVELY DRY OUTSIDE THE MOUNTAINS
WITH MINIMAL SNOW ACCUMULATIONS.

BY SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE COLD FRONT PUSHES
ACROSS THE AREA WITH THE COLDEST AIR ACROSS THE HIGH PLAINS. THIS
MAY BE THE BEST CHANCE FOR MOST AREAS TO SEE A LITTLE BIT OF LIGHT
SNOW ACCORDING TO THE SHORT TERM ENSEMBLES. INCREASED POP BETWEEN
20 TO 35 PERCENT ACROSS MOST OF THE AREA...ESPECIALLY ALONG AND
EAST OF THE LARAMIE RANGE. TEMPERATURES WILL BE BELOW NORMAL ON
SUNDAY BUT DRIER AIR WILL PUSH INTO THE AREA DURING THE AFTERNOON
AS THE TROUGH QUICKLY DIGS SOUTHEAST ACROSS THE CENTRAL PLAINS.
MODELS SHOW THE POTENTIAL FOR STRONG WINDS ACROSS SOUTHEAST
WYOMING BY LATE SUNDAY NIGHT AS A LLVL GRADIENT INCREASES ALONG
THE LARAMIE RANGE.

.LONG TERM...(MONDAY THROUGH NEXT FRIDAY)
ISSUED AT 250 PM MST FRI JAN 30 2015

MONDAY WILL START OUT BREEZY WITH WINDS ACROSS THE NORMALLY WINDIER
LOCATIONS ALONG AND WEST OF THE LARAMIE RANGE GUSTING 35 TO 45 MPH
OUT OF THE WEST IN THE MORNING AS A SHORTWAVE MOVES SOUTHEAST ACROSS
WYOMING.  THE SHORTWAVE MOVES QUICKLY OUT TO THE EAST BY MONDAY
AFTERNOON...BUT WITH THE MID/UPPER FLOW PERSISTING OUT OF THE
NORTHWEST SHOULD SEE ADDITIONAL WEAK SHORTWAVES MOVE DOWN ACROSS THE
AREA TUESDAY THROUGH THURSDAY.  WE MAY GET A PERIOD AGAIN TUESDAY
WITH SLIGHTLY INCREASED WINDS GUSTING 30-40 MPH.  KEPT CHANCES OF
SNOW GOING IN THE HIGHER TERRAIN ACROSS PORTIONS OF CARBON...ALBANY
AND WESTERN LARAMIE COUNTIES MONDAY INTO TUESDAY...BUT SNOWFALL
TOTALS SHOULD REMAIN FAIRLY LIGHT.  BY TUESDAY NIGHT...A FAIRLY
ROBUST UPPER DISTURBANCE WILL CARVE OUT AN UPPER TROUGH OVER THE
DAKOTAS AND MINNESOTA...GIVING THE ARCTIC AIRMASS LOCKED TO OUR
NORTH A QUICK SHOVE SOUTHWARD BY WEDNESDAY MORNING.  THE COLD FRONT
ON THE WESTERN EDGE OF THAT AIRMASS WILL MOVE INTO THE EASTERN HALF
OF OUR FORECAST AREA TUESDAY NIGHT BEFORE HANGING UP IN THE
MOUNTAINS.  SOME OF THE GUIDANCE CAME UP ON LOW TEMPERATURES
WEDNESDAY MORNING CONTRARY TO THE PHYSICAL GUIDANCE OF THE GFS AND
ECMWF WHICH SHOWS SHALLOW COLDER AIRMASS WORKING IN FROM THE
NORTHEAST.  FOR THIS PACKAGE WE OPTED TO STAY CLOSER TO OUR PREVIOUS
MIDNIGHT SHIFT FORECAST UNTIL GUIDANCE TRENDS BECOME MORE
CONSISTENT...KEEPING LOWS IN THE TEENS EAST OF THE LARAMIE RANGE
WEDNESDAY AND THURSDAY MORNINGS. WE ALSO KEPT SLIGHT CHANCE TO
CHANCE POPS FOR SHOWERS (SNOW WEST AND A MIX EAST) GOING ACROSS THE
AREA ON WEDNESDAY IN ASSOCIATION WITH THE SURFACE BOUNDARY AND A
PASSING UPPER DISTURBANCE.   LOOKING FARTHER OUT...UPPER RIDGING
WILL WORK IN FROM THE WEST THURSDAY INTO FRIDAY.  WE SHOULD SEE
DECREASED POPS AND A BIT OF A WARMUP LATE THURSDAY INTO FRIDAY WITH
TEMPERATURES OUT WEST ON FRIDAY IN THE 40S (EXCEPT 30S IN THE
MOUNTAINS) AND 50S OUT EAST ON THE PLAINS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1042 PM MST FRI JAN 30 2015

MAIN AVIATION CONCERN WILL BE ALONG AND NEAR THE COLORADO AND
WYOMING BORDER TONIGHT AS AN UPPER LEVEL LOW SPINS OVER THE
SOUTHWEST CONUS. SOME LIGHT SNOW IS EXPECTED IN THESE AREAS
TONIGHT BUT IT WILL BE LIGHT WITH MAINLY MVFR AND LOCALLY IFR.
THE SNOWY AND SIERRA MADRE MOUNTAINS MAY BE OBSCURED DUE TO THE
LIGHT SNOW.

WINDS WILL BE LIGHT THROUGH SATURDAY AFTERNOON BUT A COLD FRONT
WILL MOVE ACROSS THE PLAINS SATURDAY NIGHT WITH GUSTY NORTHWEST
WINDS DEVELOPING. THERE ALSO COULD BE A PERIOD OF LIGHT SNOW INTO
SOUTHERN PORTIONS OF THE NEBRASKA PANHANDLE LATE SATURDAY
AFTERNOON AND EVENING AHEAD OF THE COLD FRONT. IFR POSSIBLE WITH
THE FALLING SNOW WHICH COULD AFFECT KAIA AND KSNY. THE MAIN AREA
OF SNOW WILL SET UP EAST OF THE PANHANDLE INTO CENTRAL NEBRASKA.

&&

.FIRE WEATHER...
ISSUED AT 150 PM MST FRI JAN 30 2015

NO FIRE WEATHER CONCERNS ANTICIPATED. RECENT MILD SPRING-LIKE
CONDITIONS WILL END BY THIS WEEKEND AS AN ARCTIC COLD FRONT MOVES
SOUTHWARD ACROSS THE AREA BY SATURDAY. COOL TEMPERATURES...HIGH
RELATIVE HUMIDITIES...AND A CHANCE OF LIGHT PRECIPITATION ARE
EXPECTED INTO EARLY NEXT WEEK. ANOTHER STRONG COLD FRONT MAY
IMPACT THE REGION ON WEDNESDAY...BRINGING WIDESPREAD SNOWFALL TO
SOUTHEAST WYOMING AND PORTIONS OF WESTERN NEBRASKA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...TJT
LONG TERM...JG
AVIATION...SML
FIRE WEATHER...TJT




000
FXUS63 KUNR 310413
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
913 PM MST FRI JAN 30 2015

.UPDATE...
ISSUED AT 907 PM MST FRI JAN 30 2015

LATEST 11U-3.9U SATELLITE LOOP SHOWED ST DECK MAKING STEADY
PROGRESS SOUTH AND WEST THIS EVENING ACROSS THE NORTHEAST 2/3RDS
OF ND. DECK SHOULD CONTINUE SOUTHWEST OVERNIGHT PER LATEST
GUIDANCE AND EXTRAPOLATION...PUSHING INTO THE BLACK HILLS EARLY
SATURDAY MORNING. GIVEN BOUNDARY LAYER WINDS TURNING WEAK
UPSLOPE...THERE IS A SMALL SIGNAL FOR SOME FOG ALONG THE EASTERN
FOOTHILLS. MAY NEED TO INTRODUCE TO PUBLIC FORECASTS LATER DEPENDING
ON HOW FAR ST INFILTRATES THE REGION.

&&

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 151 PM MST FRI JAN 30 2015

WESTERN CONUS RIDGE WILL WEAKEN IN THE PERIOD...WITH A STRONG NW
FLOW IMPULSE FORCING AN ARCTIC FRONT THROUGH THE REGION SATURDAY.
THIS FEATURE WITH AN ASSOCIATED STRONG JET STREAK WILL FORCE A
PERIOD OF LIGHT SNOW OVER THE AREA MAINLY SAT NIGHT. IN
ADDITION...A SW CONUS UPPER LOW AND ITS ASSOCIATED DEEP MOISTURE
WILL SKIRT THE CENTRAL PLAINS...HELPING TO PIVOT THE LL BAROCLINIC
ZONE NEAR SCENTRAL SD...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-2 INCH
RANGE...HIGHEST ACROSS NW SD AND THE NORTHERN BH FOOTHILLS.

MILD CONDS IN PLACE ACROSS THE FA THIS AFTERNOON. HOWEVER...A
PASSING SHORTWAVE ACROSS THE SOUTHERN PRAIRIE PROVINCES OF CANADA IS
FORCING A COLD FRONT SOUTH INTO ND. THIS FRONT WILL PUSH SSW ACROSS
THE DAKOTAS...INCLUDING THE NORTHERN PORTION OF THE FA
TONIGHT...STALLING OVER THE BLACK HILLS SAT. A POTENT IMPULSE NOW
OVER SOUTHERN BC WILL QUICKLY ADVECT SE INTO THE REGION
SAT...SUPPORTING INCREASING LSA. THIS SYSTEM WILL BE ASSOCIATED WITH
A 120 KNOT JET STREAK...WITH THE LEFT EXIT REGION SPREADING OVER THE
FA. STRONG CONVERGENCE ASSOCIATED WITH AN EXPECTED ARCTIC
SURGE/STRONG LSA/AND ENHANCED LEFT EXIT FORCING WILL PRODUCE AMPLE
UVM...SUPPORTING SNOWS LATE SAT AFTERNOON INTO SATURDAY NIGHT. SNOW
WILL SPREAD SW ACROSS THE FA...WITH NW SD SEEING THE BEST
COLLOCATION OF THE AFOREMENTIONED FEATURES. ADDITIONAL UPSLOPE
ENHANCEMENT EXPECTED OVER THE NORTHERN BLACK HILLS FOOTHILLS. THESE
AREAS ARE EXPECTED TO SEE 1-2 INCHES WITH LOCALLY 3 POSSIBLE WHERE
FORCING PERSIST LONGEST. ADDITIONAL AND SEPARATE SNOWS LIKELY ACROSS
FAR EASTERN SCENTRAL SD WITH ENHANCEMENT FROM THE SKIRTING SOUTHERN
PLAINS SYSTEM MOISTURE PLUME. COLD AIR WILL SPREAD SOUTH INTO THE
REGION WITH TONIGHT/S FIRST FRONT...STALLING OVER THE BH SAT. THIS
WILL SUPPORT A LARGE TEMP SPREAD ACROSS THE FA SAT WITH 40S EXPECTED
OVER NE WY TO UPPER 20S ACROSS FAR NE PORTIONS OF THE FA. MODIFIED
ARCTIC AIR WILL SPREAD SOUTH INTO THE REGION SAT NIGHT WITH LOWS IN
THE SINGLE DIGITS MOST AREAS.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 151 PM MST FRI JAN 30 2015

SHORTWAVE ENERGY WILL CROSS THE NORTHERN PLAINS IN NORTHWEST
FLOW...BRINGING LIGHT SNOW TO PARTS OF THE AREA MONDAY INTO
TUESDAY. AN UPPER RIDGE IS PROGGED TO BUILD ACROSS THE ROCKIES
LATE NEXT WEEK...WITH DRY WEATHER EXPECTED.

THE TEMPERATURE FORECAST FOR NEXT WEEK REMAINS TRICKY AS SURFACE
FRONTAL BOUNDARY MEANDERS ACROSS THE CWA AT TIMES. UNDER A COLDER
AIRMASS...TEMPS ON SUNDAY WILL BE 10-20 DEGREES BELOW AVERAGE. FOR
THE REST OF THE EXTENDED...THE LATEST MODEL RUNS HAVE MUCH WARMER
TEMPS THAN PREVIOUSLY. THERE ARE STILL SOME TIMING ISSUES WITH THE
NEXT COLD FRONT THAT DIVES SOUTH TUESDAY...BUT THE GFS AND ECMWF
CONTINUE TO SHOW WARMER AIR MOVING BACK INTO THE REGION TOWARDS THE
END OF NEXT WEEK. WITH LOW CONFIDENCE IN MODEL TEMP
FORECASTS...COOLED TEMPS A BIT MONDAY THROUGH WEDNESDAY NIGHT TO
CURTAIL SUCH A DRASTIC CHANGE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 907 PM MST FRI JAN 30 2015

VFR CONDITIONS ARE EXPECTED TONIGHT THROUGH 09Z. AN AREA OF
IFR/MVFR ST OVER ND WILL INVADE NORTHWEST SD AFTER 09Z AND MAKE
IT TO THE BLACK HILLS AROUND 15Z AND THEN SINK SOUTH/WEST THROUGH
SATURDAY EVENING. LOCAL IFR VSBYS POSSIBLE AS ST INTERSECTS HIGHER
TERRAIN. A STORM SYSTEM WILL CREATE AN AREA OF -SN LATER SATURDAY
AFTERNOON OVER FAR NORTHWEST SD WITH IFR CIGS/VSBYS MOVING ACROSS
ENTIRE AREA SATURDAY EVENING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

UPDATE...HELGESON
SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...HELGESON




000
FXUS65 KCYS 310410
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
910 PM MST FRI JAN 30 2015

.UPDATE...
ISSUED AT 907 PM MST FRI JAN 30 2015

UPPER LEVEL LOW SPINNING OVER THE SOUTHWEST CONUS CONTINUES TO
PUSH HIGH CLOUDS INTO THE FORECAST AREA. SOME LIGHT SNOW HAS ALSO
MADE ITS WAY INTO THE SNOWY AND SIERRA MADRE RANGES. ACCUMLUATIONS
IN THE MOUNTAINS WILL BE MINIMAL WITH MAYBE AN INCH OR TWO
POSSIBLE. OTHERWISE LITTLE TO NO SNOW EXPECTED OVER THE FORECAST
AREA TONIGHT WITH NOT MUCH MORE THAN FLURRIES NEAR THE COLORADO/
WYOMING BORDER OUTSIDE OF THE MOUNTAINS. PLACES LIKE BAGS AND DIX
COULD SEE A DUSTING OF SNOW BUT THAT IS ABOUT IT. NO UPDATES
NEEDED AS TONIGHTS FORECAST IS ON TRACK.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 250 PM MST FRI JAN 30 2015

MODELS IN GOOD AGREEMENT THROUGH THIS WEEKEND SHOWING THE OVERALL
WEATHER PATTERN TRANSITIONING TOWARDS NORTH TO NORTHWEST FLOW AND
COLDER TEMPERATURES. CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE
BROAD UPPER LEVEL LOW...WHICH IS RESPONSIBLE FOR BREAKING DOWN THE
STRONG UPPER LEVEL RIDGE ALONG THE WEST COAST EARLIER THIS
WEEK...OVER SOUTHERN CALIFORNIA THIS AFTERNOON. THIS LOW WILL
INITIALLY DRIFT EASTWARD TONIGHT...HOWEVER...SATELLITE IMAGERY
SHOWS A SHORTWAVE MOVING ACROSS BRITISH COLUMBIA AND DIGGING
SOUTHEAST INTO MONTANA LATE TONIGHT AND INTO EARLY SATURDAY. THIS
FEATURE WILL BE ASSOCIATED WITH A COLD FRONT WITH A MODIFIED
ARCTIC AIRMASS PUSHING INTO THE NORTHERN PLAINS. THIS WILL RESULT
IN THE BROAD UPPER LEVEL LOW OVER THE DESERT SOUTHWEST TO BEGIN
DIGGING SOUTH AND SOUTHEAST INTO MEXICO ON SATURDAY...MAINLY
MISSING MOST OF SOUTHEAST WYOMING AND WESTERN NEBRASKA. CAN NOT
RULE OUT SOME LIGHT SNOW ALONG AND SOUTH OF I80 HOWEVER...SO KEPT
POP BETWEEN 15 TO 30 PERCENT FROM RAWLINS TO CHEYENNE TONIGHT AND
EARLY SATURDAY. THE HIGH PLAINS MAY GET CLIPPED BY THE REAR
ENTRANCE REGION OF A STRENGTHENING JET ALOFT...BUT PRECIPITATION
WILL LIKELY BE MIXED WITH RAIN DURING THE DAY. REMOVED THE
POTENTIAL FOR FOG TONIGHT AND EARLY SATURDAY SINCE THE UPPER LEVEL
LOW WILL BE TOO FAR SOUTH AND LLVL WINDS WILL BE LIGHT NORTHERLY.
THE BEST CHANCE FOR SOME LOWER VISIBILITIES WILL BE THE CHEYENNE
RIDGE FROM KIMBALL TO SIDNEY...AND MAYBE THE LOWER ELEVATIONS OF
CARBON COUNTY IF WINDS BECOME LIGHT FOR A TIME BEFORE SHIFTING
INTO THE NORTHEAST. IN ADDITION...MID TO HIGH CLOUDS WILL BE
PROBLEMATIC FOR LLVL FOG DEVELOPMENT...SO MAY JUST SEE LOW CLOUDS
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. KEPT LOW
TEMPERATURES ABOVE MODEL GUIDANCE DUE TO THIS CLOUD COVER.
TEMPERATURES WILL BE NEAR NORMAL FOR SATURDAY...WITH HIGHS IN THE
UPPER 30S TO MID 40S. WITH THE EXCEPTION OF THE EXITING JET
ALOFT...WEATHER SHOULD BE RELATIVELY DRY OUTSIDE THE MOUNTAINS
WITH MINIMAL SNOW ACCUMULATIONS.

BY SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE COLD FRONT PUSHES
ACROSS THE AREA WITH THE COLDEST AIR ACROSS THE HIGH PLAINS. THIS
MAY BE THE BEST CHANCE FOR MOST AREAS TO SEE A LITTLE BIT OF LIGHT
SNOW ACCORDING TO THE SHORT TERM ENSEMBLES. INCREASED POP BETWEEN
20 TO 35 PERCENT ACROSS MOST OF THE AREA...ESPECIALLY ALONG AND
EAST OF THE LARAMIE RANGE. TEMPERATURES WILL BE BELOW NORMAL ON
SUNDAY BUT DRIER AIR WILL PUSH INTO THE AREA DURING THE AFTERNOON
AS THE TROUGH QUICKLY DIGS SOUTHEAST ACROSS THE CENTRAL PLAINS.
MODELS SHOW THE POTENTIAL FOR STRONG WINDS ACROSS SOUTHEAST
WYOMING BY LATE SUNDAY NIGHT AS A LLVL GRADIENT INCREASES ALONG
THE LARAMIE RANGE.

.LONG TERM...(MONDAY THROUGH NEXT FRIDAY)
ISSUED AT 250 PM MST FRI JAN 30 2015

MONDAY WILL START OUT BREEZY WITH WINDS ACROSS THE NORMALLY WINDIER
LOCATIONS ALONG AND WEST OF THE LARAMIE RANGE GUSTING 35 TO 45 MPH
OUT OF THE WEST IN THE MORNING AS A SHORTWAVE MOVES SOUTHEAST ACROSS
WYOMING.  THE SHORTWAVE MOVES QUICKLY OUT TO THE EAST BY MONDAY
AFTERNOON...BUT WITH THE MID/UPPER FLOW PERSISTING OUT OF THE
NORTHWEST SHOULD SEE ADDITIONAL WEAK SHORTWAVES MOVE DOWN ACROSS THE
AREA TUESDAY THROUGH THURSDAY.  WE MAY GET A PERIOD AGAIN TUESDAY
WITH SLIGHTLY INCREASED WINDS GUSTING 30-40 MPH.  KEPT CHANCES OF
SNOW GOING IN THE HIGHER TERRAIN ACROSS PORTIONS OF CARBON...ALBANY
AND WESTERN LARAMIE COUNTIES MONDAY INTO TUESDAY...BUT SNOWFALL
TOTALS SHOULD REMAIN FAIRLY LIGHT.  BY TUESDAY NIGHT...A FAIRLY
ROBUST UPPER DISTURBANCE WILL CARVE OUT AN UPPER TROUGH OVER THE
DAKOTAS AND MINNESOTA...GIVING THE ARCTIC AIRMASS LOCKED TO OUR
NORTH A QUICK SHOVE SOUTHWARD BY WEDNESDAY MORNING.  THE COLD FRONT
ON THE WESTERN EDGE OF THAT AIRMASS WILL MOVE INTO THE EASTERN HALF
OF OUR FORECAST AREA TUESDAY NIGHT BEFORE HANGING UP IN THE
MOUNTAINS.  SOME OF THE GUIDANCE CAME UP ON LOW TEMPERATURES
WEDNESDAY MORNING CONTRARY TO THE PHYSICAL GUIDANCE OF THE GFS AND
ECMWF WHICH SHOWS SHALLOW COLDER AIRMASS WORKING IN FROM THE
NORTHEAST.  FOR THIS PACKAGE WE OPTED TO STAY CLOSER TO OUR PREVIOUS
MIDNIGHT SHIFT FORECAST UNTIL GUIDANCE TRENDS BECOME MORE
CONSISTENT...KEEPING LOWS IN THE TEENS EAST OF THE LARAMIE RANGE
WEDNESDAY AND THURSDAY MORNINGS. WE ALSO KEPT SLIGHT CHANCE TO
CHANCE POPS FOR SHOWERS (SNOW WEST AND A MIX EAST) GOING ACROSS THE
AREA ON WEDNESDAY IN ASSOCIATION WITH THE SURFACE BOUNDARY AND A
PASSING UPPER DISTURBANCE.   LOOKING FARTHER OUT...UPPER RIDGING
WILL WORK IN FROM THE WEST THURSDAY INTO FRIDAY.  WE SHOULD SEE
DECREASED POPS AND A BIT OF A WARMUP LATE THURSDAY INTO FRIDAY WITH
TEMPERATURES OUT WEST ON FRIDAY IN THE 40S (EXCEPT 30S IN THE
MOUNTAINS) AND 50S OUT EAST ON THE PLAINS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 445 PM MST FRI JAN 30 2015

MAIN AVIATION CONCERN WILL BE ALONG AND NEAR THE COLORADO AND
WYOMING BORDER TONIGHT AS AN UPPER LEVEL LOW SPINS OVER THE
SOUTHWEST CONUS. SOME LIGHT SNOW IS EXPECTED IN THESE AREAS
TONIGHT BUT IT WILL BE LIGHT WITH MAINLY MVFR AND LOCALLY IFR.
THE SNOWY AND SIERRA MADRE MOUNTAINS WILL BE OBSCURRED DUE TO THE
LIGHT SNOW. WINDS WILL BE LIGHT THROUGH THE TAF PERIOD.


&&

.FIRE WEATHER...
ISSUED AT 150 PM MST FRI JAN 30 2015

NO FIRE WEATHER CONCERNS ANTICIPATED. RECENT MILD SPRING-LIKE
CONDITIONS WILL END BY THIS WEEKEND AS AN ARCTIC COLD FRONT MOVES
SOUTHWARD ACROSS THE AREA BY SATURDAY. COOL TEMPERATURES...HIGH
RELATIVE HUMIDITIES...AND A CHANCE OF LIGHT PRECIPITATION ARE
EXPECTED INTO EARLY NEXT WEEK. ANOTHER STRONG COLD FRONT MAY
IMPACT THE REGION ON WEDNESDAY...BRINGING WIDESPREAD SNOWFALL TO
SOUTHEAST WYOMING AND PORTIONS OF WESTERN NEBRASKA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...TJT
LONG TERM...JG
AVIATION...SML
FIRE WEATHER...TJT



000
FXUS65 KCYS 310410
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
910 PM MST FRI JAN 30 2015

.UPDATE...
ISSUED AT 907 PM MST FRI JAN 30 2015

UPPER LEVEL LOW SPINNING OVER THE SOUTHWEST CONUS CONTINUES TO
PUSH HIGH CLOUDS INTO THE FORECAST AREA. SOME LIGHT SNOW HAS ALSO
MADE ITS WAY INTO THE SNOWY AND SIERRA MADRE RANGES. ACCUMLUATIONS
IN THE MOUNTAINS WILL BE MINIMAL WITH MAYBE AN INCH OR TWO
POSSIBLE. OTHERWISE LITTLE TO NO SNOW EXPECTED OVER THE FORECAST
AREA TONIGHT WITH NOT MUCH MORE THAN FLURRIES NEAR THE COLORADO/
WYOMING BORDER OUTSIDE OF THE MOUNTAINS. PLACES LIKE BAGS AND DIX
COULD SEE A DUSTING OF SNOW BUT THAT IS ABOUT IT. NO UPDATES
NEEDED AS TONIGHTS FORECAST IS ON TRACK.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 250 PM MST FRI JAN 30 2015

MODELS IN GOOD AGREEMENT THROUGH THIS WEEKEND SHOWING THE OVERALL
WEATHER PATTERN TRANSITIONING TOWARDS NORTH TO NORTHWEST FLOW AND
COLDER TEMPERATURES. CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE
BROAD UPPER LEVEL LOW...WHICH IS RESPONSIBLE FOR BREAKING DOWN THE
STRONG UPPER LEVEL RIDGE ALONG THE WEST COAST EARLIER THIS
WEEK...OVER SOUTHERN CALIFORNIA THIS AFTERNOON. THIS LOW WILL
INITIALLY DRIFT EASTWARD TONIGHT...HOWEVER...SATELLITE IMAGERY
SHOWS A SHORTWAVE MOVING ACROSS BRITISH COLUMBIA AND DIGGING
SOUTHEAST INTO MONTANA LATE TONIGHT AND INTO EARLY SATURDAY. THIS
FEATURE WILL BE ASSOCIATED WITH A COLD FRONT WITH A MODIFIED
ARCTIC AIRMASS PUSHING INTO THE NORTHERN PLAINS. THIS WILL RESULT
IN THE BROAD UPPER LEVEL LOW OVER THE DESERT SOUTHWEST TO BEGIN
DIGGING SOUTH AND SOUTHEAST INTO MEXICO ON SATURDAY...MAINLY
MISSING MOST OF SOUTHEAST WYOMING AND WESTERN NEBRASKA. CAN NOT
RULE OUT SOME LIGHT SNOW ALONG AND SOUTH OF I80 HOWEVER...SO KEPT
POP BETWEEN 15 TO 30 PERCENT FROM RAWLINS TO CHEYENNE TONIGHT AND
EARLY SATURDAY. THE HIGH PLAINS MAY GET CLIPPED BY THE REAR
ENTRANCE REGION OF A STRENGTHENING JET ALOFT...BUT PRECIPITATION
WILL LIKELY BE MIXED WITH RAIN DURING THE DAY. REMOVED THE
POTENTIAL FOR FOG TONIGHT AND EARLY SATURDAY SINCE THE UPPER LEVEL
LOW WILL BE TOO FAR SOUTH AND LLVL WINDS WILL BE LIGHT NORTHERLY.
THE BEST CHANCE FOR SOME LOWER VISIBILITIES WILL BE THE CHEYENNE
RIDGE FROM KIMBALL TO SIDNEY...AND MAYBE THE LOWER ELEVATIONS OF
CARBON COUNTY IF WINDS BECOME LIGHT FOR A TIME BEFORE SHIFTING
INTO THE NORTHEAST. IN ADDITION...MID TO HIGH CLOUDS WILL BE
PROBLEMATIC FOR LLVL FOG DEVELOPMENT...SO MAY JUST SEE LOW CLOUDS
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. KEPT LOW
TEMPERATURES ABOVE MODEL GUIDANCE DUE TO THIS CLOUD COVER.
TEMPERATURES WILL BE NEAR NORMAL FOR SATURDAY...WITH HIGHS IN THE
UPPER 30S TO MID 40S. WITH THE EXCEPTION OF THE EXITING JET
ALOFT...WEATHER SHOULD BE RELATIVELY DRY OUTSIDE THE MOUNTAINS
WITH MINIMAL SNOW ACCUMULATIONS.

BY SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE COLD FRONT PUSHES
ACROSS THE AREA WITH THE COLDEST AIR ACROSS THE HIGH PLAINS. THIS
MAY BE THE BEST CHANCE FOR MOST AREAS TO SEE A LITTLE BIT OF LIGHT
SNOW ACCORDING TO THE SHORT TERM ENSEMBLES. INCREASED POP BETWEEN
20 TO 35 PERCENT ACROSS MOST OF THE AREA...ESPECIALLY ALONG AND
EAST OF THE LARAMIE RANGE. TEMPERATURES WILL BE BELOW NORMAL ON
SUNDAY BUT DRIER AIR WILL PUSH INTO THE AREA DURING THE AFTERNOON
AS THE TROUGH QUICKLY DIGS SOUTHEAST ACROSS THE CENTRAL PLAINS.
MODELS SHOW THE POTENTIAL FOR STRONG WINDS ACROSS SOUTHEAST
WYOMING BY LATE SUNDAY NIGHT AS A LLVL GRADIENT INCREASES ALONG
THE LARAMIE RANGE.

.LONG TERM...(MONDAY THROUGH NEXT FRIDAY)
ISSUED AT 250 PM MST FRI JAN 30 2015

MONDAY WILL START OUT BREEZY WITH WINDS ACROSS THE NORMALLY WINDIER
LOCATIONS ALONG AND WEST OF THE LARAMIE RANGE GUSTING 35 TO 45 MPH
OUT OF THE WEST IN THE MORNING AS A SHORTWAVE MOVES SOUTHEAST ACROSS
WYOMING.  THE SHORTWAVE MOVES QUICKLY OUT TO THE EAST BY MONDAY
AFTERNOON...BUT WITH THE MID/UPPER FLOW PERSISTING OUT OF THE
NORTHWEST SHOULD SEE ADDITIONAL WEAK SHORTWAVES MOVE DOWN ACROSS THE
AREA TUESDAY THROUGH THURSDAY.  WE MAY GET A PERIOD AGAIN TUESDAY
WITH SLIGHTLY INCREASED WINDS GUSTING 30-40 MPH.  KEPT CHANCES OF
SNOW GOING IN THE HIGHER TERRAIN ACROSS PORTIONS OF CARBON...ALBANY
AND WESTERN LARAMIE COUNTIES MONDAY INTO TUESDAY...BUT SNOWFALL
TOTALS SHOULD REMAIN FAIRLY LIGHT.  BY TUESDAY NIGHT...A FAIRLY
ROBUST UPPER DISTURBANCE WILL CARVE OUT AN UPPER TROUGH OVER THE
DAKOTAS AND MINNESOTA...GIVING THE ARCTIC AIRMASS LOCKED TO OUR
NORTH A QUICK SHOVE SOUTHWARD BY WEDNESDAY MORNING.  THE COLD FRONT
ON THE WESTERN EDGE OF THAT AIRMASS WILL MOVE INTO THE EASTERN HALF
OF OUR FORECAST AREA TUESDAY NIGHT BEFORE HANGING UP IN THE
MOUNTAINS.  SOME OF THE GUIDANCE CAME UP ON LOW TEMPERATURES
WEDNESDAY MORNING CONTRARY TO THE PHYSICAL GUIDANCE OF THE GFS AND
ECMWF WHICH SHOWS SHALLOW COLDER AIRMASS WORKING IN FROM THE
NORTHEAST.  FOR THIS PACKAGE WE OPTED TO STAY CLOSER TO OUR PREVIOUS
MIDNIGHT SHIFT FORECAST UNTIL GUIDANCE TRENDS BECOME MORE
CONSISTENT...KEEPING LOWS IN THE TEENS EAST OF THE LARAMIE RANGE
WEDNESDAY AND THURSDAY MORNINGS. WE ALSO KEPT SLIGHT CHANCE TO
CHANCE POPS FOR SHOWERS (SNOW WEST AND A MIX EAST) GOING ACROSS THE
AREA ON WEDNESDAY IN ASSOCIATION WITH THE SURFACE BOUNDARY AND A
PASSING UPPER DISTURBANCE.   LOOKING FARTHER OUT...UPPER RIDGING
WILL WORK IN FROM THE WEST THURSDAY INTO FRIDAY.  WE SHOULD SEE
DECREASED POPS AND A BIT OF A WARMUP LATE THURSDAY INTO FRIDAY WITH
TEMPERATURES OUT WEST ON FRIDAY IN THE 40S (EXCEPT 30S IN THE
MOUNTAINS) AND 50S OUT EAST ON THE PLAINS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 445 PM MST FRI JAN 30 2015

MAIN AVIATION CONCERN WILL BE ALONG AND NEAR THE COLORADO AND
WYOMING BORDER TONIGHT AS AN UPPER LEVEL LOW SPINS OVER THE
SOUTHWEST CONUS. SOME LIGHT SNOW IS EXPECTED IN THESE AREAS
TONIGHT BUT IT WILL BE LIGHT WITH MAINLY MVFR AND LOCALLY IFR.
THE SNOWY AND SIERRA MADRE MOUNTAINS WILL BE OBSCURRED DUE TO THE
LIGHT SNOW. WINDS WILL BE LIGHT THROUGH THE TAF PERIOD.


&&

.FIRE WEATHER...
ISSUED AT 150 PM MST FRI JAN 30 2015

NO FIRE WEATHER CONCERNS ANTICIPATED. RECENT MILD SPRING-LIKE
CONDITIONS WILL END BY THIS WEEKEND AS AN ARCTIC COLD FRONT MOVES
SOUTHWARD ACROSS THE AREA BY SATURDAY. COOL TEMPERATURES...HIGH
RELATIVE HUMIDITIES...AND A CHANCE OF LIGHT PRECIPITATION ARE
EXPECTED INTO EARLY NEXT WEEK. ANOTHER STRONG COLD FRONT MAY
IMPACT THE REGION ON WEDNESDAY...BRINGING WIDESPREAD SNOWFALL TO
SOUTHEAST WYOMING AND PORTIONS OF WESTERN NEBRASKA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

UPDATE...SML
SHORT TERM...TJT
LONG TERM...JG
AVIATION...SML
FIRE WEATHER...TJT




000
FXUS63 KUNR 310014
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
514 PM MST FRI JAN 30 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 151 PM MST FRI JAN 30 2015

WESTERN CONUS RIDGE WILL WEAKEN IN THE PERIOD...WITH A STRONG NW
FLOW IMPULSE FORCING AN ARCTIC FRONT THROUGH THE REGION SATURDAY.
THIS FEATURE WITH AN ASSOCIATED STRONG JET STREAK WILL FORCE A
PERIOD OF LIGHT SNOW OVER THE AREA MAINLY SAT NIGHT. IN
ADDITION...A SW CONUS UPPER LOW AND ITS ASSOCIATED DEEP MOISTURE
WILL SKIRT THE CENTRAL PLAINS...HELPING TO PIVOT THE LL BAROCLINIC
ZONE NEAR SCENTRAL SD...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-2 INCH
RANGE...HIGHEST ACROSS NW SD AND THE NORTHERN BH FOOTHILLS.

MILD CONDS IN PLACE ACROSS THE FA THIS AFTERNOON. HOWEVER...A
PASSING SHORTWAVE ACROSS THE SOUTHERN PRAIRIE PROVINCES OF CANADA IS
FORCING A COLD FRONT SOUTH INTO ND. THIS FRONT WILL PUSH SSW ACROSS
THE DAKOTAS...INCLUDING THE NORTHERN PORTION OF THE FA
TONIGHT...STALLING OVER THE BLACK HILLS SAT. A POTENT IMPULSE NOW
OVER SOUTHERN BC WILL QUICKLY ADVECT SE INTO THE REGION
SAT...SUPPORTING INCREASING LSA. THIS SYSTEM WILL BE ASSOCIATED WITH
A 120 KNOT JET STREAK...WITH THE LEFT EXIT REGION SPREADING OVER THE
FA. STRONG CONVERGENCE ASSOCIATED WITH AN EXPECTED ARCTIC
SURGE/STRONG LSA/AND ENHANCED LEFT EXIT FORCING WILL PRODUCE AMPLE
UVM...SUPPORTING SNOWS LATE SAT AFTERNOON INTO SATURDAY NIGHT. SNOW
WILL SPREAD SW ACROSS THE FA...WITH NW SD SEEING THE BEST
COLLOCATION OF THE AFOREMENTIONED FEATURES. ADDITIONAL UPSLOPE
ENHANCEMENT EXPECTED OVER THE NORTHERN BLACK HILLS FOOTHILLS. THESE
AREAS ARE EXPECTED TO SEE 1-2 INCHES WITH LOCALLY 3 POSSIBLE WHERE
FORCING PERSIST LONGEST. ADDITIONAL AND SEPARATE SNOWS LIKELY ACROSS
FAR EASTERN SCENTRAL SD WITH ENHANCEMENT FROM THE SKIRTING SOUTHERN
PLAINS SYSTEM MOISTURE PLUME. COLD AIR WILL SPREAD SOUTH INTO THE
REGION WITH TONIGHT/S FIRST FRONT...STALLING OVER THE BH SAT. THIS
WILL SUPPORT A LARGE TEMP SPREAD ACROSS THE FA SAT WITH 40S EXPECTED
OVER NE WY TO UPPER 20S ACROSS FAR NE PORTIONS OF THE FA. MODIFIED
ARCTIC AIR WILL SPREAD SOUTH INTO THE REGION SAT NIGHT WITH LOWS IN
THE SINGLE DIGITS MOST AREAS.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 151 PM MST FRI JAN 30 2015

SHORTWAVE ENERGY WILL CROSS THE NORTHERN PLAINS IN NORTHWEST
FLOW...BRINGING LIGHT SNOW TO PARTS OF THE AREA MONDAY INTO
TUESDAY. AN UPPER RIDGE IS PROGGED TO BUILD ACROSS THE ROCKIES
LATE NEXT WEEK...WITH DRY WEATHER EXPECTED.

THE TEMPERATURE FORECAST FOR NEXT WEEK REMAINS TRICKY AS SURFACE
FRONTAL BOUNDARY MEANDERS ACROSS THE CWA AT TIMES. UNDER A COLDER
AIRMASS...TEMPS ON SUNDAY WILL BE 10-20 DEGREES BELOW AVERAGE. FOR
THE REST OF THE EXTENDED...THE LATEST MODEL RUNS HAVE MUCH WARMER
TEMPS THAN PREVIOUSLY. THERE ARE STILL SOME TIMING ISSUES WITH THE
NEXT COLD FRONT THAT DIVES SOUTH TUESDAY...BUT THE GFS AND ECMWF
CONTINUE TO SHOW WARMER AIR MOVING BACK INTO THE REGION TOWARDS THE
END OF NEXT WEEK. WITH LOW CONFIDENCE IN MODEL TEMP
FORECASTS...COOLED TEMPS A BIT MONDAY THROUGH WEDNESDAY NIGHT TO
CURTAIL SUCH A DRASTIC CHANGE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 511 PM MST FRI JAN 30 2015

VFR CONDITIONS ARE EXPECTED TONIGHT. AN AREA OF MVFR CIGS WILL
DEVELOP/ADVECT INTO NORTHEAST PORTIONS OF THE AREA SATURDAY
MORNING...AND THEN SLOWLY MOVE SOUTHWEST DURING THE DAY. A STORM
SYSTEM WILL CREATE AN AREA OF -SN SATURDAY AFTERNOON OVER FAR
NORTHWEST SD WITH IFR CIGS/VSBYS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...HELGESON




000
FXUS63 KUNR 310014
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
514 PM MST FRI JAN 30 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 151 PM MST FRI JAN 30 2015

WESTERN CONUS RIDGE WILL WEAKEN IN THE PERIOD...WITH A STRONG NW
FLOW IMPULSE FORCING AN ARCTIC FRONT THROUGH THE REGION SATURDAY.
THIS FEATURE WITH AN ASSOCIATED STRONG JET STREAK WILL FORCE A
PERIOD OF LIGHT SNOW OVER THE AREA MAINLY SAT NIGHT. IN
ADDITION...A SW CONUS UPPER LOW AND ITS ASSOCIATED DEEP MOISTURE
WILL SKIRT THE CENTRAL PLAINS...HELPING TO PIVOT THE LL BAROCLINIC
ZONE NEAR SCENTRAL SD...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-2 INCH
RANGE...HIGHEST ACROSS NW SD AND THE NORTHERN BH FOOTHILLS.

MILD CONDS IN PLACE ACROSS THE FA THIS AFTERNOON. HOWEVER...A
PASSING SHORTWAVE ACROSS THE SOUTHERN PRAIRIE PROVINCES OF CANADA IS
FORCING A COLD FRONT SOUTH INTO ND. THIS FRONT WILL PUSH SSW ACROSS
THE DAKOTAS...INCLUDING THE NORTHERN PORTION OF THE FA
TONIGHT...STALLING OVER THE BLACK HILLS SAT. A POTENT IMPULSE NOW
OVER SOUTHERN BC WILL QUICKLY ADVECT SE INTO THE REGION
SAT...SUPPORTING INCREASING LSA. THIS SYSTEM WILL BE ASSOCIATED WITH
A 120 KNOT JET STREAK...WITH THE LEFT EXIT REGION SPREADING OVER THE
FA. STRONG CONVERGENCE ASSOCIATED WITH AN EXPECTED ARCTIC
SURGE/STRONG LSA/AND ENHANCED LEFT EXIT FORCING WILL PRODUCE AMPLE
UVM...SUPPORTING SNOWS LATE SAT AFTERNOON INTO SATURDAY NIGHT. SNOW
WILL SPREAD SW ACROSS THE FA...WITH NW SD SEEING THE BEST
COLLOCATION OF THE AFOREMENTIONED FEATURES. ADDITIONAL UPSLOPE
ENHANCEMENT EXPECTED OVER THE NORTHERN BLACK HILLS FOOTHILLS. THESE
AREAS ARE EXPECTED TO SEE 1-2 INCHES WITH LOCALLY 3 POSSIBLE WHERE
FORCING PERSIST LONGEST. ADDITIONAL AND SEPARATE SNOWS LIKELY ACROSS
FAR EASTERN SCENTRAL SD WITH ENHANCEMENT FROM THE SKIRTING SOUTHERN
PLAINS SYSTEM MOISTURE PLUME. COLD AIR WILL SPREAD SOUTH INTO THE
REGION WITH TONIGHT/S FIRST FRONT...STALLING OVER THE BH SAT. THIS
WILL SUPPORT A LARGE TEMP SPREAD ACROSS THE FA SAT WITH 40S EXPECTED
OVER NE WY TO UPPER 20S ACROSS FAR NE PORTIONS OF THE FA. MODIFIED
ARCTIC AIR WILL SPREAD SOUTH INTO THE REGION SAT NIGHT WITH LOWS IN
THE SINGLE DIGITS MOST AREAS.

.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 151 PM MST FRI JAN 30 2015

SHORTWAVE ENERGY WILL CROSS THE NORTHERN PLAINS IN NORTHWEST
FLOW...BRINGING LIGHT SNOW TO PARTS OF THE AREA MONDAY INTO
TUESDAY. AN UPPER RIDGE IS PROGGED TO BUILD ACROSS THE ROCKIES
LATE NEXT WEEK...WITH DRY WEATHER EXPECTED.

THE TEMPERATURE FORECAST FOR NEXT WEEK REMAINS TRICKY AS SURFACE
FRONTAL BOUNDARY MEANDERS ACROSS THE CWA AT TIMES. UNDER A COLDER
AIRMASS...TEMPS ON SUNDAY WILL BE 10-20 DEGREES BELOW AVERAGE. FOR
THE REST OF THE EXTENDED...THE LATEST MODEL RUNS HAVE MUCH WARMER
TEMPS THAN PREVIOUSLY. THERE ARE STILL SOME TIMING ISSUES WITH THE
NEXT COLD FRONT THAT DIVES SOUTH TUESDAY...BUT THE GFS AND ECMWF
CONTINUE TO SHOW WARMER AIR MOVING BACK INTO THE REGION TOWARDS THE
END OF NEXT WEEK. WITH LOW CONFIDENCE IN MODEL TEMP
FORECASTS...COOLED TEMPS A BIT MONDAY THROUGH WEDNESDAY NIGHT TO
CURTAIL SUCH A DRASTIC CHANGE.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 511 PM MST FRI JAN 30 2015

VFR CONDITIONS ARE EXPECTED TONIGHT. AN AREA OF MVFR CIGS WILL
DEVELOP/ADVECT INTO NORTHEAST PORTIONS OF THE AREA SATURDAY
MORNING...AND THEN SLOWLY MOVE SOUTHWEST DURING THE DAY. A STORM
SYSTEM WILL CREATE AN AREA OF -SN SATURDAY AFTERNOON OVER FAR
NORTHWEST SD WITH IFR CIGS/VSBYS.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...HELGESON





000
FXUS65 KCYS 310004
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
504 PM MST FRI JAN 30 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 250 PM MST FRI JAN 30 2015

MODELS IN GOOD AGREEMENT THROUGH THIS WEEKEND SHOWING THE OVERALL
WEATHER PATTERN TRANSITIONING TOWARDS NORTH TO NORTHWEST FLOW AND
COLDER TEMPERATURES. CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE
BROAD UPPER LEVEL LOW...WHICH IS RESPONSIBLE FOR BREAKING DOWN THE
STRONG UPPER LEVEL RIDGE ALONG THE WEST COAST EARLIER THIS
WEEK...OVER SOUTHERN CALIFORNIA THIS AFTERNOON. THIS LOW WILL
INITIALLY DRIFT EASTWARD TONIGHT...HOWEVER...SATELLITE IMAGERY
SHOWS A SHORTWAVE MOVING ACROSS BRITISH COLUMBIA AND DIGGING
SOUTHEAST INTO MONTANA LATE TONIGHT AND INTO EARLY SATURDAY. THIS
FEATURE WILL BE ASSOCIATED WITH A COLD FRONT WITH A MODIFIED
ARCTIC AIRMASS PUSHING INTO THE NORTHERN PLAINS. THIS WILL RESULT
IN THE BROAD UPPER LEVEL LOW OVER THE DESERT SOUTHWEST TO BEGIN
DIGGING SOUTH AND SOUTHEAST INTO MEXICO ON SATURDAY...MAINLY
MISSING MOST OF SOUTHEAST WYOMING AND WESTERN NEBRASKA. CAN NOT
RULE OUT SOME LIGHT SNOW ALONG AND SOUTH OF I80 HOWEVER...SO KEPT
POP BETWEEN 15 TO 30 PERCENT FROM RAWLINS TO CHEYENNE TONIGHT AND
EARLY SATURDAY. THE HIGH PLAINS MAY GET CLIPPED BY THE REAR
ENTRANCE REGION OF A STRENGTHENING JET ALOFT...BUT PRECIPITATION
WILL LIKELY BE MIXED WITH RAIN DURING THE DAY. REMOVED THE
POTENTIAL FOR FOG TONIGHT AND EARLY SATURDAY SINCE THE UPPER LEVEL
LOW WILL BE TOO FAR SOUTH AND LLVL WINDS WILL BE LIGHT NORTHERLY.
THE BEST CHANCE FOR SOME LOWER VISIBILITIES WILL BE THE CHEYENNE
RIDGE FROM KIMBALL TO SIDNEY...AND MAYBE THE LOWER ELEVATIONS OF
CARBON COUNTY IF WINDS BECOME LIGHT FOR A TIME BEFORE SHIFTING
INTO THE NORTHEAST. IN ADDITION...MID TO HIGH CLOUDS WILL BE
PROBLEMATIC FOR LLVL FOG DEVELOPMENT...SO MAY JUST SEE LOW CLOUDS
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. KEPT LOW
TEMPERATURES ABOVE MODEL GUIDANCE DUE TO THIS CLOUD COVER.
TEMPERATURES WILL BE NEAR NORMAL FOR SATURDAY...WITH HIGHS IN THE
UPPER 30S TO MID 40S. WITH THE EXCEPTION OF THE EXITING JET
ALOFT...WEATHER SHOULD BE RELATIVELY DRY OUTSIDE THE MOUNTAINS
WITH MINIMAL SNOW ACCUMULATIONS.

BY SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE COLD FRONT PUSHES
ACROSS THE AREA WITH THE COLDEST AIR ACROSS THE HIGH PLAINS. THIS
MAY BE THE BEST CHANCE FOR MOST AREAS TO SEE A LITTLE BIT OF LIGHT
SNOW ACCORDING TO THE SHORT TERM ENSEMBLES. INCREASED POP BETWEEN
20 TO 35 PERCENT ACROSS MOST OF THE AREA...ESPECIALLY ALONG AND
EAST OF THE LARAMIE RANGE. TEMPERATURES WILL BE BELOW NORMAL ON
SUNDAY BUT DRIER AIR WILL PUSH INTO THE AREA DURING THE AFTERNOON
AS THE TROUGH QUICKLY DIGS SOUTHEAST ACROSS THE CENTRAL PLAINS.
MODELS SHOW THE POTENTIAL FOR STRONG WINDS ACROSS SOUTHEAST
WYOMING BY LATE SUNDAY NIGHT AS A LLVL GRADIENT INCREASES ALONG
THE LARAMIE RANGE.

.LONG TERM...(MONDAY THROUGH NEXT FRIDAY)
ISSUED AT 250 PM MST FRI JAN 30 2015

MONDAY WILL START OUT BREEZY WITH WINDS ACROSS THE NORMALLY WINDIER
LOCATIONS ALONG AND WEST OF THE LARAMIE RANGE GUSTING 35 TO 45 MPH
OUT OF THE WEST IN THE MORNING AS A SHORTWAVE MOVES SOUTHEAST ACROSS
WYOMING.  THE SHORTWAVE MOVES QUICKLY OUT TO THE EAST BY MONDAY
AFTERNOON...BUT WITH THE MID/UPPER FLOW PERSISTING OUT OF THE
NORTHWEST SHOULD SEE ADDITIONAL WEAK SHORTWAVES MOVE DOWN ACROSS THE
AREA TUESDAY THROUGH THURSDAY.  WE MAY GET A PERIOD AGAIN TUESDAY
WITH SLIGHTLY INCREASED WINDS GUSTING 30-40 MPH.  KEPT CHANCES OF
SNOW GOING IN THE HIGHER TERRAIN ACROSS PORTIONS OF CARBON...ALBANY
AND WESTERN LARAMIE COUNTIES MONDAY INTO TUESDAY...BUT SNOWFALL
TOTALS SHOULD REMAIN FAIRLY LIGHT.  BY TUESDAY NIGHT...A FAIRLY
ROBUST UPPER DISTURBANCE WILL CARVE OUT AN UPPER TROUGH OVER THE
DAKOTAS AND MINNESOTA...GIVING THE ARCTIC AIRMASS LOCKED TO OUR
NORTH A QUICK SHOVE SOUTHWARD BY WEDNESDAY MORNING.  THE COLD FRONT
ON THE WESTERN EDGE OF THAT AIRMASS WILL MOVE INTO THE EASTERN HALF
OF OUR FORECAST AREA TUESDAY NIGHT BEFORE HANGING UP IN THE
MOUNTAINS.  SOME OF THE GUIDANCE CAME UP ON LOW TEMPERATURES
WEDNESDAY MORNING CONTRARY TO THE PHYSICAL GUIDANCE OF THE GFS AND
ECMWF WHICH SHOWS SHALLOW COLDER AIRMASS WORKING IN FROM THE
NORTHEAST.  FOR THIS PACKAGE WE OPTED TO STAY CLOSER TO OUR PREVIOUS
MIDNIGHT SHIFT FORECAST UNTIL GUIDANCE TRENDS BECOME MORE
CONSISTENT...KEEPING LOWS IN THE TEENS EAST OF THE LARAMIE RANGE
WEDNESDAY AND THURSDAY MORNINGS. WE ALSO KEPT SLIGHT CHANCE TO
CHANCE POPS FOR SHOWERS (SNOW WEST AND A MIX EAST) GOING ACROSS THE
AREA ON WEDNESDAY IN ASSOCIATION WITH THE SURFACE BOUNDARY AND A
PASSING UPPER DISTURBANCE.   LOOKING FARTHER OUT...UPPER RIDGING
WILL WORK IN FROM THE WEST THURSDAY INTO FRIDAY.  WE SHOULD SEE
DECREASED POPS AND A BIT OF A WARMUP LATE THURSDAY INTO FRIDAY WITH
TEMPERATURES OUT WEST ON FRIDAY IN THE 40S (EXCEPT 30S IN THE
MOUNTAINS) AND 50S OUT EAST ON THE PLAINS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 445 PM MST FRI JAN 30 2015

MAIN AVIATION CONCERN WILL BE ALONG AND NEAR THE COLORADO AND
WYOMING BORDER TONIGHT AS AN UPPER LEVEL LOW SPINS OVER THE
SOUTHWEST CONUS. SOME LIGHT SNOW IS EXPECTED IN THESE AREAS
TONIGHT BUT IT WILL BE LIGHT WITH MAINLY MVFR AND LOCALLY IFR.
THE SNOWY AND SIERRA MADRE MOUNTAINS WILL BE OBSCURRED DUE TO THE
LIGHT SNOW. WINDS WILL BE LIGHT THROUGH THE TAF PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 150 PM MST FRI JAN 30 2015

NO FIRE WEATHER CONCERNS ANTICIPATED. RECENT MILD SPRING-LIKE
CONDITIONS WILL END BY THIS WEEKEND AS AN ARCTIC COLD FRONT MOVES
SOUTHWARD ACROSS THE AREA BY SATURDAY. COOL TEMPERATURES...HIGH
RELATIVE HUMIDITIES...AND A CHANCE OF LIGHT PRECIPITATION ARE
EXPECTED INTO EARLY NEXT WEEK. ANOTHER STRONG COLD FRONT MAY
IMPACT THE REGION ON WEDNESDAY...BRINGING WIDESPREAD SNOWFALL TO
SOUTHEAST WYOMING AND PORTIONS OF WESTERN NEBRASKA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...TJT
LONG TERM...JG
AVIATION...SML
FIRE WEATHER...TJT




000
FXUS65 KCYS 310004
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
504 PM MST FRI JAN 30 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 250 PM MST FRI JAN 30 2015

MODELS IN GOOD AGREEMENT THROUGH THIS WEEKEND SHOWING THE OVERALL
WEATHER PATTERN TRANSITIONING TOWARDS NORTH TO NORTHWEST FLOW AND
COLDER TEMPERATURES. CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE
BROAD UPPER LEVEL LOW...WHICH IS RESPONSIBLE FOR BREAKING DOWN THE
STRONG UPPER LEVEL RIDGE ALONG THE WEST COAST EARLIER THIS
WEEK...OVER SOUTHERN CALIFORNIA THIS AFTERNOON. THIS LOW WILL
INITIALLY DRIFT EASTWARD TONIGHT...HOWEVER...SATELLITE IMAGERY
SHOWS A SHORTWAVE MOVING ACROSS BRITISH COLUMBIA AND DIGGING
SOUTHEAST INTO MONTANA LATE TONIGHT AND INTO EARLY SATURDAY. THIS
FEATURE WILL BE ASSOCIATED WITH A COLD FRONT WITH A MODIFIED
ARCTIC AIRMASS PUSHING INTO THE NORTHERN PLAINS. THIS WILL RESULT
IN THE BROAD UPPER LEVEL LOW OVER THE DESERT SOUTHWEST TO BEGIN
DIGGING SOUTH AND SOUTHEAST INTO MEXICO ON SATURDAY...MAINLY
MISSING MOST OF SOUTHEAST WYOMING AND WESTERN NEBRASKA. CAN NOT
RULE OUT SOME LIGHT SNOW ALONG AND SOUTH OF I80 HOWEVER...SO KEPT
POP BETWEEN 15 TO 30 PERCENT FROM RAWLINS TO CHEYENNE TONIGHT AND
EARLY SATURDAY. THE HIGH PLAINS MAY GET CLIPPED BY THE REAR
ENTRANCE REGION OF A STRENGTHENING JET ALOFT...BUT PRECIPITATION
WILL LIKELY BE MIXED WITH RAIN DURING THE DAY. REMOVED THE
POTENTIAL FOR FOG TONIGHT AND EARLY SATURDAY SINCE THE UPPER LEVEL
LOW WILL BE TOO FAR SOUTH AND LLVL WINDS WILL BE LIGHT NORTHERLY.
THE BEST CHANCE FOR SOME LOWER VISIBILITIES WILL BE THE CHEYENNE
RIDGE FROM KIMBALL TO SIDNEY...AND MAYBE THE LOWER ELEVATIONS OF
CARBON COUNTY IF WINDS BECOME LIGHT FOR A TIME BEFORE SHIFTING
INTO THE NORTHEAST. IN ADDITION...MID TO HIGH CLOUDS WILL BE
PROBLEMATIC FOR LLVL FOG DEVELOPMENT...SO MAY JUST SEE LOW CLOUDS
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. KEPT LOW
TEMPERATURES ABOVE MODEL GUIDANCE DUE TO THIS CLOUD COVER.
TEMPERATURES WILL BE NEAR NORMAL FOR SATURDAY...WITH HIGHS IN THE
UPPER 30S TO MID 40S. WITH THE EXCEPTION OF THE EXITING JET
ALOFT...WEATHER SHOULD BE RELATIVELY DRY OUTSIDE THE MOUNTAINS
WITH MINIMAL SNOW ACCUMULATIONS.

BY SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE COLD FRONT PUSHES
ACROSS THE AREA WITH THE COLDEST AIR ACROSS THE HIGH PLAINS. THIS
MAY BE THE BEST CHANCE FOR MOST AREAS TO SEE A LITTLE BIT OF LIGHT
SNOW ACCORDING TO THE SHORT TERM ENSEMBLES. INCREASED POP BETWEEN
20 TO 35 PERCENT ACROSS MOST OF THE AREA...ESPECIALLY ALONG AND
EAST OF THE LARAMIE RANGE. TEMPERATURES WILL BE BELOW NORMAL ON
SUNDAY BUT DRIER AIR WILL PUSH INTO THE AREA DURING THE AFTERNOON
AS THE TROUGH QUICKLY DIGS SOUTHEAST ACROSS THE CENTRAL PLAINS.
MODELS SHOW THE POTENTIAL FOR STRONG WINDS ACROSS SOUTHEAST
WYOMING BY LATE SUNDAY NIGHT AS A LLVL GRADIENT INCREASES ALONG
THE LARAMIE RANGE.

.LONG TERM...(MONDAY THROUGH NEXT FRIDAY)
ISSUED AT 250 PM MST FRI JAN 30 2015

MONDAY WILL START OUT BREEZY WITH WINDS ACROSS THE NORMALLY WINDIER
LOCATIONS ALONG AND WEST OF THE LARAMIE RANGE GUSTING 35 TO 45 MPH
OUT OF THE WEST IN THE MORNING AS A SHORTWAVE MOVES SOUTHEAST ACROSS
WYOMING.  THE SHORTWAVE MOVES QUICKLY OUT TO THE EAST BY MONDAY
AFTERNOON...BUT WITH THE MID/UPPER FLOW PERSISTING OUT OF THE
NORTHWEST SHOULD SEE ADDITIONAL WEAK SHORTWAVES MOVE DOWN ACROSS THE
AREA TUESDAY THROUGH THURSDAY.  WE MAY GET A PERIOD AGAIN TUESDAY
WITH SLIGHTLY INCREASED WINDS GUSTING 30-40 MPH.  KEPT CHANCES OF
SNOW GOING IN THE HIGHER TERRAIN ACROSS PORTIONS OF CARBON...ALBANY
AND WESTERN LARAMIE COUNTIES MONDAY INTO TUESDAY...BUT SNOWFALL
TOTALS SHOULD REMAIN FAIRLY LIGHT.  BY TUESDAY NIGHT...A FAIRLY
ROBUST UPPER DISTURBANCE WILL CARVE OUT AN UPPER TROUGH OVER THE
DAKOTAS AND MINNESOTA...GIVING THE ARCTIC AIRMASS LOCKED TO OUR
NORTH A QUICK SHOVE SOUTHWARD BY WEDNESDAY MORNING.  THE COLD FRONT
ON THE WESTERN EDGE OF THAT AIRMASS WILL MOVE INTO THE EASTERN HALF
OF OUR FORECAST AREA TUESDAY NIGHT BEFORE HANGING UP IN THE
MOUNTAINS.  SOME OF THE GUIDANCE CAME UP ON LOW TEMPERATURES
WEDNESDAY MORNING CONTRARY TO THE PHYSICAL GUIDANCE OF THE GFS AND
ECMWF WHICH SHOWS SHALLOW COLDER AIRMASS WORKING IN FROM THE
NORTHEAST.  FOR THIS PACKAGE WE OPTED TO STAY CLOSER TO OUR PREVIOUS
MIDNIGHT SHIFT FORECAST UNTIL GUIDANCE TRENDS BECOME MORE
CONSISTENT...KEEPING LOWS IN THE TEENS EAST OF THE LARAMIE RANGE
WEDNESDAY AND THURSDAY MORNINGS. WE ALSO KEPT SLIGHT CHANCE TO
CHANCE POPS FOR SHOWERS (SNOW WEST AND A MIX EAST) GOING ACROSS THE
AREA ON WEDNESDAY IN ASSOCIATION WITH THE SURFACE BOUNDARY AND A
PASSING UPPER DISTURBANCE.   LOOKING FARTHER OUT...UPPER RIDGING
WILL WORK IN FROM THE WEST THURSDAY INTO FRIDAY.  WE SHOULD SEE
DECREASED POPS AND A BIT OF A WARMUP LATE THURSDAY INTO FRIDAY WITH
TEMPERATURES OUT WEST ON FRIDAY IN THE 40S (EXCEPT 30S IN THE
MOUNTAINS) AND 50S OUT EAST ON THE PLAINS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 445 PM MST FRI JAN 30 2015

MAIN AVIATION CONCERN WILL BE ALONG AND NEAR THE COLORADO AND
WYOMING BORDER TONIGHT AS AN UPPER LEVEL LOW SPINS OVER THE
SOUTHWEST CONUS. SOME LIGHT SNOW IS EXPECTED IN THESE AREAS
TONIGHT BUT IT WILL BE LIGHT WITH MAINLY MVFR AND LOCALLY IFR.
THE SNOWY AND SIERRA MADRE MOUNTAINS WILL BE OBSCURRED DUE TO THE
LIGHT SNOW. WINDS WILL BE LIGHT THROUGH THE TAF PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 150 PM MST FRI JAN 30 2015

NO FIRE WEATHER CONCERNS ANTICIPATED. RECENT MILD SPRING-LIKE
CONDITIONS WILL END BY THIS WEEKEND AS AN ARCTIC COLD FRONT MOVES
SOUTHWARD ACROSS THE AREA BY SATURDAY. COOL TEMPERATURES...HIGH
RELATIVE HUMIDITIES...AND A CHANCE OF LIGHT PRECIPITATION ARE
EXPECTED INTO EARLY NEXT WEEK. ANOTHER STRONG COLD FRONT MAY
IMPACT THE REGION ON WEDNESDAY...BRINGING WIDESPREAD SNOWFALL TO
SOUTHEAST WYOMING AND PORTIONS OF WESTERN NEBRASKA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...TJT
LONG TERM...JG
AVIATION...SML
FIRE WEATHER...TJT



000
FXUS65 KCYS 302210
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
310 PM MST FRI JAN 30 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 250 PM MST FRI JAN 30 2015

MODELS IN GOOD AGREEMENT THROUGH THIS WEEKEND SHOWING THE OVERALL
WEATHER PATTERN TRANSITIONING TOWARDS NORTH TO NORTHWEST FLOW AND
COLDER TEMPERATURES. CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE
BROAD UPPER LEVEL LOW...WHICH IS RESPONSIBLE FOR BREAKING DOWN THE
STRONG UPPER LEVEL RIDGE ALONG THE WEST COAST EARLIER THIS
WEEK...OVER SOUTHERN CALIFORNIA THIS AFTERNOON. THIS LOW WILL
INITIALLY DRIFT EASTWARD TONIGHT...HOWEVER...SATELLITE IMAGERY
SHOWS A SHORTWAVE MOVING ACROSS BRITISH COLUMBIA AND DIGGING
SOUTHEAST INTO MONTANA LATE TONIGHT AND INTO EARLY SATURDAY. THIS
FEATURE WILL BE ASSOCIATED WITH A COLD FRONT WITH A MODIFIED
ARCTIC AIRMASS PUSHING INTO THE NORTHERN PLAINS. THIS WILL RESULT
IN THE BROAD UPPER LEVEL LOW OVER THE DESERT SOUTHWEST TO BEGIN
DIGGING SOUTH AND SOUTHEAST INTO MEXICO ON SATURDAY...MAINLY
MISSING MOST OF SOUTHEAST WYOMING AND WESTERN NEBRASKA. CAN NOT
RULE OUT SOME LIGHT SNOW ALONG AND SOUTH OF I80 HOWEVER...SO KEPT
POP BETWEEN 15 TO 30 PERCENT FROM RAWLINS TO CHEYENNE TONIGHT AND
EARLY SATURDAY. THE HIGH PLAINS MAY GET CLIPPED BY THE REAR
ENTRANCE REGION OF A STRENGTHENING JET ALOFT...BUT PRECIPITATION
WILL LIKELY BE MIXED WITH RAIN DURING THE DAY. REMOVED THE
POTENTIAL FOR FOG TONIGHT AND EARLY SATURDAY SINCE THE UPPER LEVEL
LOW WILL BE TOO FAR SOUTH AND LLVL WINDS WILL BE LIGHT NORTHERLY.
THE BEST CHANCE FOR SOME LOWER VISIBILITIES WILL BE THE CHEYENNE
RIDGE FROM KIMBALL TO SIDNEY...AND MAYBE THE LOWER ELEVATIONS OF
CARBON COUNTY IF WINDS BECOME LIGHT FOR A TIME BEFORE SHIFTING
INTO THE NORTHEAST. IN ADDITION...MID TO HIGH CLOUDS WILL BE
PROBLEMATIC FOR LLVL FOG DEVELOPMENT...SO MAY JUST SEE LOW CLOUDS
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. KEPT LOW
TEMPERATURES ABOVE MODEL GUIDANCE DUE TO THIS CLOUD COVER.
TEMPERATURES WILL BE NEAR NORMAL FOR SATURDAY...WITH HIGHS IN THE
UPPER 30S TO MID 40S. WITH THE EXCEPTION OF THE EXITING JET
ALOFT...WEATHER SHOULD BE RELATIVELY DRY OUTSIDE THE MOUNTAINS
WITH MINIMAL SNOW ACCUMULATIONS.

BY SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE COLD FRONT PUSHES
ACROSS THE AREA WITH THE COLDEST AIR ACROSS THE HIGH PLAINS. THIS
MAY BE THE BEST CHANCE FOR MOST AREAS TO SEE A LITTLE BIT OF LIGHT
SNOW ACCORDING TO THE SHORT TERM ENSEMBLES. INCREASED POP BETWEEN
20 TO 35 PERCENT ACROSS MOST OF THE AREA...ESPECIALLY ALONG AND
EAST OF THE LARAMIE RANGE. TEMPERATURES WILL BE BELOW NORMAL ON
SUNDAY BUT DRIER AIR WILL PUSH INTO THE AREA DURING THE AFTERNOON
AS THE TROUGH QUICKLY DIGS SOUTHEAST ACROSS THE CENTRAL PLAINS.
MODELS SHOW THE POTENTIAL FOR STRONG WINDS ACROSS SOUTHEAST
WYOMING BY LATE SUNDAY NIGHT AS A LLVL GRADIENT INCREASES ALONG
THE LARAMIE RANGE.

.LONG TERM...(MONDAY THROUGH NEXT FRIDAY)
ISSUED AT 250 PM MST FRI JAN 30 2015

MONDAY WILL START OUT BREEZY WITH WINDS ACROSS THE NORMALLY WINDIER
LOCATIONS ALONG AND WEST OF THE LARAMIE RANGE GUSTING 35 TO 45 MPH
OUT OF THE WEST IN THE MORNING AS A SHORTWAVE MOVES SOUTHEAST ACROSS
WYOMING.  THE SHORTWAVE MOVES QUICKLY OUT TO THE EAST BY MONDAY
AFTERNOON...BUT WITH THE MID/UPPER FLOW PERSISTING OUT OF THE
NORTHWEST SHOULD SEE ADDITIONAL WEAK SHORTWAVES MOVE DOWN ACROSS THE
AREA TUESDAY THROUGH THURSDAY.  WE MAY GET A PERIOD AGAIN TUESDAY
WITH SLIGHTLY INCREASED WINDS GUSTING 30-40 MPH.  KEPT CHANCES OF
SNOW GOING IN THE HIGHER TERRAIN ACROSS PORTIONS OF CARBON...ALBANY
AND WESTERN LARAMIE COUNTIES MONDAY INTO TUESDAY...BUT SNOWFALL
TOTALS SHOULD REMAIN FAIRLY LIGHT.  BY TUESDAY NIGHT...A FAIRLY
ROBUST UPPER DISTURBANCE WILL CARVE OUT AN UPPER TROUGH OVER THE
DAKOTAS AND MINNESOTA...GIVING THE ARCTIC AIRMASS LOCKED TO OUR
NORTH A QUICK SHOVE SOUTHWARD BY WEDNESDAY MORNING.  THE COLD FRONT
ON THE WESTERN EDGE OF THAT AIRMASS WILL MOVE INTO THE EASTERN HALF
OF OUR FORECAST AREA TUESDAY NIGHT BEFORE HANGING UP IN THE
MOUNTAINS.  SOME OF THE GUIDANCE CAME UP ON LOW TEMPERATURES
WEDNESDAY MORNING CONTRARY TO THE PHYSICAL GUIDANCE OF THE GFS AND
ECMWF WHICH SHOWS SHALLOW COLDER AIRMASS WORKING IN FROM THE
NORTHEAST.  FOR THIS PACKAGE WE OPTED TO STAY CLOSER TO OUR PREVIOUS
MIDNIGHT SHIFT FORECAST UNTIL GUIDANCE TRENDS BECOME MORE
CONSISTENT...KEEPING LOWS IN THE TEENS EAST OF THE LARAMIE RANGE
WEDNESDAY AND THURSDAY MORNINGS. WE ALSO KEPT SLIGHT CHANCE TO
CHANCE POPS FOR SHOWERS (SNOW WEST AND A MIX EAST) GOING ACROSS THE
AREA ON WEDNESDAY IN ASSOCIATION WITH THE SURFACE BOUNDARY AND A
PASSING UPPER DISTURBANCE.   LOOKING FARTHER OUT...UPPER RIDGING
WILL WORK IN FROM THE WEST THURSDAY INTO FRIDAY.  WE SHOULD SEE
DECREASED POPS AND A BIT OF A WARMUP LATE THURSDAY INTO FRIDAY WITH
TEMPERATURES OUT WEST ON FRIDAY IN THE 40S (EXCEPT 30S IN THE
MOUNTAINS) AND 50S OUT EAST ON THE PLAINS.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1114 AM MST FRI JAN 30 2015

CURRENTLY GETTING MVFR CATEGORY OBSERVED AT RAWLINS WY WHERE LIGHT
SNOW SHOWERS ARE PRODUCING VISIBILITIES DOWN TO 2SM...BUT THAT
SHOULD NOT BE A PREVAILING CONDITION THROUGH THE AFTERNOON WITH MVFR
CEILINGS BKN 2000FT AGL EXPECTED. OTHERWISE REST OF FORECAST AREA
EXPECTED TO SEE VFR CONDITIONS THROUGH THE EVENING WITH LOWERING
CEILINGS TO MVFR ACROSS THE ALLIANCE AND SIDNEY NE AREAS LATER
TONIGHT WITH LIGHT SOUTHERLY FLOW. MAY GET SOME PATCHY FOG IN SPOTS
TONIGHT (PARTICULARLY WHERE ANY LIGHT UPSLOW DEVELOPS). WILL ALSO
SEE A CHANCE OF LIGHT SNOW WITH MVFR CATEGORY CONDITIONS POSSIBLE
RAWLINS AND LARAMIE CLOSER TO WHERE ORAGRAPHICALLY INDUCED SNOW
SHOWERS IN THE MOUNTAINS ARE EXPECTED...BUT OTHERWISE NO MAJOR
CONCERNS THROUGH TOMORROW MORNING AND WE DONT EXPECT TO SEE
PREVAILING REDUCED VISIBILITIES DUE TO SNOW FOR THOSE LOCATIONS
THROUGH MORNING. THE HIGHER SNOW CHANCES THROUGH MORNING ARE
EXPECTED TO BE TO OUR SOUTH IN THE COLORADO MOUNTAINS.

&&

.FIRE WEATHER...
ISSUED AT 150 PM MST FRI JAN 30 2015

NO FIRE WEATHER CONCERNS ANTICIPATED. RECENT MILD SPRING-LIKE
CONDITIONS WILL END BY THIS WEEKEND AS AN ARCTIC COLD FRONT MOVES
SOUTHWARD ACROSS THE AREA BY SATURDAY. COOL TEMPERATURES...HIGH
RELATIVE HUMIDITIES...AND A CHANCE OF LIGHT PRECIPITATION ARE
EXPECTED INTO EARLY NEXT WEEK. ANOTHER STRONG COLD FRONT MAY
IMPACT THE REGION ON WEDNESDAY...BRINGING WIDESPREAD SNOWFALL TO
SOUTHEAST WYOMING AND PORTIONS OF WESTERN NEBRASKA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...TJT
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...TJT



000
FXUS65 KCYS 302210
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
310 PM MST FRI JAN 30 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 250 PM MST FRI JAN 30 2015

MODELS IN GOOD AGREEMENT THROUGH THIS WEEKEND SHOWING THE OVERALL
WEATHER PATTERN TRANSITIONING TOWARDS NORTH TO NORTHWEST FLOW AND
COLDER TEMPERATURES. CURRENT WATERVAPOR SATELLITE LOOP SHOWS THE
BROAD UPPER LEVEL LOW...WHICH IS RESPONSIBLE FOR BREAKING DOWN THE
STRONG UPPER LEVEL RIDGE ALONG THE WEST COAST EARLIER THIS
WEEK...OVER SOUTHERN CALIFORNIA THIS AFTERNOON. THIS LOW WILL
INITIALLY DRIFT EASTWARD TONIGHT...HOWEVER...SATELLITE IMAGERY
SHOWS A SHORTWAVE MOVING ACROSS BRITISH COLUMBIA AND DIGGING
SOUTHEAST INTO MONTANA LATE TONIGHT AND INTO EARLY SATURDAY. THIS
FEATURE WILL BE ASSOCIATED WITH A COLD FRONT WITH A MODIFIED
ARCTIC AIRMASS PUSHING INTO THE NORTHERN PLAINS. THIS WILL RESULT
IN THE BROAD UPPER LEVEL LOW OVER THE DESERT SOUTHWEST TO BEGIN
DIGGING SOUTH AND SOUTHEAST INTO MEXICO ON SATURDAY...MAINLY
MISSING MOST OF SOUTHEAST WYOMING AND WESTERN NEBRASKA. CAN NOT
RULE OUT SOME LIGHT SNOW ALONG AND SOUTH OF I80 HOWEVER...SO KEPT
POP BETWEEN 15 TO 30 PERCENT FROM RAWLINS TO CHEYENNE TONIGHT AND
EARLY SATURDAY. THE HIGH PLAINS MAY GET CLIPPED BY THE REAR
ENTRANCE REGION OF A STRENGTHENING JET ALOFT...BUT PRECIPITATION
WILL LIKELY BE MIXED WITH RAIN DURING THE DAY. REMOVED THE
POTENTIAL FOR FOG TONIGHT AND EARLY SATURDAY SINCE THE UPPER LEVEL
LOW WILL BE TOO FAR SOUTH AND LLVL WINDS WILL BE LIGHT NORTHERLY.
THE BEST CHANCE FOR SOME LOWER VISIBILITIES WILL BE THE CHEYENNE
RIDGE FROM KIMBALL TO SIDNEY...AND MAYBE THE LOWER ELEVATIONS OF
CARBON COUNTY IF WINDS BECOME LIGHT FOR A TIME BEFORE SHIFTING
INTO THE NORTHEAST. IN ADDITION...MID TO HIGH CLOUDS WILL BE
PROBLEMATIC FOR LLVL FOG DEVELOPMENT...SO MAY JUST SEE LOW CLOUDS
ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. KEPT LOW
TEMPERATURES ABOVE MODEL GUIDANCE DUE TO THIS CLOUD COVER.
TEMPERATURES WILL BE NEAR NORMAL FOR SATURDAY...WITH HIGHS IN THE
UPPER 30S TO MID 40S. WITH THE EXCEPTION OF THE EXITING JET
ALOFT...WEATHER SHOULD BE RELATIVELY DRY OUTSIDE THE MOUNTAINS
WITH MINIMAL SNOW ACCUMULATIONS.

BY SATURDAY NIGHT THROUGH SUNDAY NIGHT...THE COLD FRONT PUSHES
ACROSS THE AREA WITH THE COLDEST AIR ACROSS THE HIGH PLAINS. THIS
MAY BE THE BEST CHANCE FOR MOST AREAS TO SEE A LITTLE BIT OF LIGHT
SNOW ACCORDING TO THE SHORT TERM ENSEMBLES. INCREASED POP BETWEEN
20 TO 35 PERCENT ACROSS MOST OF THE AREA...ESPECIALLY ALONG AND
EAST OF THE LARAMIE RANGE. TEMPERATURES WILL BE BELOW NORMAL ON
SUNDAY BUT DRIER AIR WILL PUSH INTO THE AREA DURING THE AFTERNOON
AS THE TROUGH QUICKLY DIGS SOUTHEAST ACROSS THE CENTRAL PLAINS.
MODELS SHOW THE POTENTIAL FOR STRONG WINDS ACROSS SOUTHEAST
WYOMING BY LATE SUNDAY NIGHT AS A LLVL GRADIENT INCREASES ALONG
THE LARAMIE RANGE.

.LONG TERM...(MONDAY THROUGH NEXT FRIDAY)
ISSUED AT 250 PM MST FRI JAN 30 2015

MONDAY WILL START OUT BREEZY WITH WINDS ACROSS THE NORMALLY WINDIER
LOCATIONS ALONG AND WEST OF THE LARAMIE RANGE GUSTING 35 TO 45 MPH
OUT OF THE WEST IN THE MORNING AS A SHORTWAVE MOVES SOUTHEAST ACROSS
WYOMING.  THE SHORTWAVE MOVES QUICKLY OUT TO THE EAST BY MONDAY
AFTERNOON...BUT WITH THE MID/UPPER FLOW PERSISTING OUT OF THE
NORTHWEST SHOULD SEE ADDITIONAL WEAK SHORTWAVES MOVE DOWN ACROSS THE
AREA TUESDAY THROUGH THURSDAY.  WE MAY GET A PERIOD AGAIN TUESDAY
WITH SLIGHTLY INCREASED WINDS GUSTING 30-40 MPH.  KEPT CHANCES OF
SNOW GOING IN THE HIGHER TERRAIN ACROSS PORTIONS OF CARBON...ALBANY
AND WESTERN LARAMIE COUNTIES MONDAY INTO TUESDAY...BUT SNOWFALL
TOTALS SHOULD REMAIN FAIRLY LIGHT.  BY TUESDAY NIGHT...A FAIRLY
ROBUST UPPER DISTURBANCE WILL CARVE OUT AN UPPER TROUGH OVER THE
DAKOTAS AND MINNESOTA...GIVING THE ARCTIC AIRMASS LOCKED TO OUR
NORTH A QUICK SHOVE SOUTHWARD BY WEDNESDAY MORNING.  THE COLD FRONT
ON THE WESTERN EDGE OF THAT AIRMASS WILL MOVE INTO THE EASTERN HALF
OF OUR FORECAST AREA TUESDAY NIGHT BEFORE HANGING UP IN THE
MOUNTAINS.  SOME OF THE GUIDANCE CAME UP ON LOW TEMPERATURES
WEDNESDAY MORNING CONTRARY TO THE PHYSICAL GUIDANCE OF THE GFS AND
ECMWF WHICH SHOWS SHALLOW COLDER AIRMASS WORKING IN FROM THE
NORTHEAST.  FOR THIS PACKAGE WE OPTED TO STAY CLOSER TO OUR PREVIOUS
MIDNIGHT SHIFT FORECAST UNTIL GUIDANCE TRENDS BECOME MORE
CONSISTENT...KEEPING LOWS IN THE TEENS EAST OF THE LARAMIE RANGE
WEDNESDAY AND THURSDAY MORNINGS. WE ALSO KEPT SLIGHT CHANCE TO
CHANCE POPS FOR SHOWERS (SNOW WEST AND A MIX EAST) GOING ACROSS THE
AREA ON WEDNESDAY IN ASSOCIATION WITH THE SURFACE BOUNDARY AND A
PASSING UPPER DISTURBANCE.   LOOKING FARTHER OUT...UPPER RIDGING
WILL WORK IN FROM THE WEST THURSDAY INTO FRIDAY.  WE SHOULD SEE
DECREASED POPS AND A BIT OF A WARMUP LATE THURSDAY INTO FRIDAY WITH
TEMPERATURES OUT WEST ON FRIDAY IN THE 40S (EXCEPT 30S IN THE
MOUNTAINS) AND 50S OUT EAST ON THE PLAINS.


&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1114 AM MST FRI JAN 30 2015

CURRENTLY GETTING MVFR CATEGORY OBSERVED AT RAWLINS WY WHERE LIGHT
SNOW SHOWERS ARE PRODUCING VISIBILITIES DOWN TO 2SM...BUT THAT
SHOULD NOT BE A PREVAILING CONDITION THROUGH THE AFTERNOON WITH MVFR
CEILINGS BKN 2000FT AGL EXPECTED. OTHERWISE REST OF FORECAST AREA
EXPECTED TO SEE VFR CONDITIONS THROUGH THE EVENING WITH LOWERING
CEILINGS TO MVFR ACROSS THE ALLIANCE AND SIDNEY NE AREAS LATER
TONIGHT WITH LIGHT SOUTHERLY FLOW. MAY GET SOME PATCHY FOG IN SPOTS
TONIGHT (PARTICULARLY WHERE ANY LIGHT UPSLOW DEVELOPS). WILL ALSO
SEE A CHANCE OF LIGHT SNOW WITH MVFR CATEGORY CONDITIONS POSSIBLE
RAWLINS AND LARAMIE CLOSER TO WHERE ORAGRAPHICALLY INDUCED SNOW
SHOWERS IN THE MOUNTAINS ARE EXPECTED...BUT OTHERWISE NO MAJOR
CONCERNS THROUGH TOMORROW MORNING AND WE DONT EXPECT TO SEE
PREVAILING REDUCED VISIBILITIES DUE TO SNOW FOR THOSE LOCATIONS
THROUGH MORNING. THE HIGHER SNOW CHANCES THROUGH MORNING ARE
EXPECTED TO BE TO OUR SOUTH IN THE COLORADO MOUNTAINS.

&&

.FIRE WEATHER...
ISSUED AT 150 PM MST FRI JAN 30 2015

NO FIRE WEATHER CONCERNS ANTICIPATED. RECENT MILD SPRING-LIKE
CONDITIONS WILL END BY THIS WEEKEND AS AN ARCTIC COLD FRONT MOVES
SOUTHWARD ACROSS THE AREA BY SATURDAY. COOL TEMPERATURES...HIGH
RELATIVE HUMIDITIES...AND A CHANCE OF LIGHT PRECIPITATION ARE
EXPECTED INTO EARLY NEXT WEEK. ANOTHER STRONG COLD FRONT MAY
IMPACT THE REGION ON WEDNESDAY...BRINGING WIDESPREAD SNOWFALL TO
SOUTHEAST WYOMING AND PORTIONS OF WESTERN NEBRASKA.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...TJT
LONG TERM...JG
AVIATION...JG
FIRE WEATHER...TJT




000
FXUS65 KRIW 302130
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
230 PM MST FRI JAN 30 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

A WARM PACIFIC LOW OVER THE FOUR CORNERS AREA THIS
AFTERNOON...CONTINUES TO STREAM HIGH CLOUDS ACROSS THE COWBOY
STATE. LOW CLOUDS HAVE MADE THEIR WAY INTO THE I-80 CORRIDOR NEAR
KRKS...WHILE THE RAIN SHOWERS REMAIN WELL TO THE SOUTH IN NE
UT/NW CO. THESE SHOWERS WILL SLOWLY MAKE THEIR WAY NORTHWARD THIS
EVENING. TEMPERATURES ARE EXPECTED TO BE AT OR BELOW FREEZING BY
THIS TIME...PRODUCING LIGHT SNOW SHOWERS ACROSS SWEETWATER COUNTY.
ACCUMULATIONS ARE EXPECTED TO REMAIN LIGHT THROUGH MID MORNING
SATURDAY.

FOG CONTINUES TO HOLD ON OVER NORTHERN PORTIONS OF THE BIGHORN
BASIN...DESPITE THE CLOUDS ALOFT. FOG WILL BEGIN TO FILL IN
FURTHER SOUTH TOWARD KWRL DURING THE OVERNIGHT HOURS. FOG SHOULD
LIFT OUT BY MID MORNING...AS SKIES BEGIN TO CLEAR ACROSS THE AREA.

A COLD FRONT WILL BEGIN TO IMPACT NORTHERN PORTIONS LATE SATURDAY
AFTERNOON...BRINGING LOW CLOUDS AND GUSTY WINDS TO JOHNSON COUNTY.
LIGHT SNOW SHOWERS WILL BE POSSIBLE IN THE BIGHORNS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY NIGHT

THE SHORTWAVE MOVING THROUGH NORTHEASTERN WYOMING SATURDAY NIGHT
WILL HAVE SOME IMPACT OVER THE EASTERN PORTION OF THE FORECAST AREA
THROUGH SUNDAY MORNING. LIGHT SHOWER ACTIVITY IS EXPECTED.

BUILDING NORTHWEST FLOW THEN EXPECTED SUNDAY AFTERNOON AND EVENING
AS A RIDGE OF HIGH PRESSURE BUILDS OFF THE PACIFIC COAST. THIS
SYSTEM WILL BRING SOME MOISTURE INTO NORTHWESTERN WYOMING EARLY
MONDAY MORNING...MAINLY IMPACTING WESTERN AND NORTHERN WYOMING.

ANOTHER...MORE SIGNIFICANT PUSH OF MOISTURE WILL FOLLOW THAT SYSTEM
QUICKLY...WITH PRECIPITATION SPREADING INTO WESTERN WYOMING MONDAY
EVENING. ACTIVITY FROM THIS SYSTEM WILL LINGER THROUGH WEDNESDAY AS
ANOTHER PUSH COMES DOWN FROM THE NORTH AS WELL. THE ACTIVITY WILL
SPREAD TO INCLUDE MUCH OF THE FORECAST AREA. MODELS HAVE SOME
VARIATIONS ON THIS SYSTEM...WITH THE GFS REMAINING THE MOST
AGGRESSIVE MODEL. HOWEVER...ALL MODELS ARE IN FAIR AGREEMENT THAT
COVERAGE WILL INCREASE THROUGH WEDNESDAY MORNING.

CONDITIONS TO IMPROVE WEDNESDAY AFTERNOON AND EVENING. A BUILDING
RIDGE WILL HELP TO CLEAR OUT ACTIVITY...THOUGH SOME VERY LIGHT
ACTIVITY MAY REMAIN POSSIBLE ACROSS THE NORTHWEST THROUGH THURSDAY
AFTERNOON. DRY CONDITIONS EXPECTED BY FRIDAY MORNING...WHICH MAY NOT
LAST LONG.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

VFR CONDITIONS WILL PREVAIL THIS EVENING...WITH FOG LINGERING IN
THE BIGHORN BASIN NEAR KGEY. FOG WILL SPREAD THROUGHOUT THE
NIGHT...REACHING KWRL BY 10Z SATURDAY. N-NE SFC WINDS WILL
PREVAIL ACROSS THE AREA...WITH SOME LOWER CIGS EXPECTED ALONG THE
EAST SLOPES OF THE DIVIDE AND OTHER UPSLOPE FAVORED AREAS. MOST OF
THESE CIGS ARE EXPECTED TO REMAIN VFR...OBSCURING HIGHER MTNS.
CLEARING IS EXPECTED AFTER 12Z SATURDAY...WITH IMPROVING
CONDITIONS FROM NORTH TO SOUTH THROUGH THE DAY. THIS WILL BE
SHORT-LIVED...AS A COLD FRONT BEGINS TO IMPACT KCOD-KWRL WITH MVFR
CONDITIONS BY 23Z SATURDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

AN UPPER LEVEL LOW PRESSURE SYSTEM OVER THE FOUR CORNERS...WILL
CONTINUE TO PUSH UP MOISTURE INTO SOUTHERN WYOMING THROUGH THE
PERIOD...WITH CIGS EXPECTED TO GRADUALLY LOWER VCNTY AND SOUTH OF
INTERSTATE 80...WITH SOME ISOLD TO SCT -SHSN MOVING IN EARLY THIS
EVENING ALONG WITH LOCAL MVFR/IFR CONDITIONS. MVFR/IFR CONDITIONS ARE
EXPECTED TO BECOME MORE PREVALENT IN THIS AREA AFTER 00Z SATURDAY.
VFR CONDITIONS WILL RETURN TO THESE AREAS AFTER 15Z
SATURDAY...WITH INCREASING WESTERLY WINDS OF 15 TO 25 MPH BY 21Z.

NORTH OF INTERSTATE 80...VFR CONDITIONS WILL PREVAIL THROUGH THE
PERIOD.

&&

.FIRE WEATHER...

FIRE DANGER IS LOW FOR ALL AREAS...AND WILL REMAIN SO THROUGH NEXT
WEEK. MEASURABLE PRECIPITATION WILL NOT FALL ACROSS THE FORECAST
AREA UNTIL LATE SATURDAY INTO SUNDAY MORNING EAST OF THE DIVIDE.
FROM SUNDAY NIGHT THROUGH THE NEXT WORK WEEK...A SERIES OF
DISTURBANCES WILL RIDE THROUGH THE REGION...AFFECTING MAINLY THE
WESTERN AND NORTHERN DISPATCH ZONES. SATURDAY WILL SEE
IMPROVEMENT IN BOTH MIXING ABILITY AND DISPERSION...ESPECIALLY
EAST OF THE DIVIDE AND ACROSS THE SOUTHERN ZONES.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...LAVOIE
LONG TERM...BRANHAM
AVIATION...LAVOIE
FIRE WEATHER...LAVOIE






000
FXUS65 KRIW 302130
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
230 PM MST FRI JAN 30 2015

.SHORT TERM...TONIGHT THROUGH SATURDAY

A WARM PACIFIC LOW OVER THE FOUR CORNERS AREA THIS
AFTERNOON...CONTINUES TO STREAM HIGH CLOUDS ACROSS THE COWBOY
STATE. LOW CLOUDS HAVE MADE THEIR WAY INTO THE I-80 CORRIDOR NEAR
KRKS...WHILE THE RAIN SHOWERS REMAIN WELL TO THE SOUTH IN NE
UT/NW CO. THESE SHOWERS WILL SLOWLY MAKE THEIR WAY NORTHWARD THIS
EVENING. TEMPERATURES ARE EXPECTED TO BE AT OR BELOW FREEZING BY
THIS TIME...PRODUCING LIGHT SNOW SHOWERS ACROSS SWEETWATER COUNTY.
ACCUMULATIONS ARE EXPECTED TO REMAIN LIGHT THROUGH MID MORNING
SATURDAY.

FOG CONTINUES TO HOLD ON OVER NORTHERN PORTIONS OF THE BIGHORN
BASIN...DESPITE THE CLOUDS ALOFT. FOG WILL BEGIN TO FILL IN
FURTHER SOUTH TOWARD KWRL DURING THE OVERNIGHT HOURS. FOG SHOULD
LIFT OUT BY MID MORNING...AS SKIES BEGIN TO CLEAR ACROSS THE AREA.

A COLD FRONT WILL BEGIN TO IMPACT NORTHERN PORTIONS LATE SATURDAY
AFTERNOON...BRINGING LOW CLOUDS AND GUSTY WINDS TO JOHNSON COUNTY.
LIGHT SNOW SHOWERS WILL BE POSSIBLE IN THE BIGHORNS.

.LONG TERM...SATURDAY NIGHT THROUGH FRIDAY NIGHT

THE SHORTWAVE MOVING THROUGH NORTHEASTERN WYOMING SATURDAY NIGHT
WILL HAVE SOME IMPACT OVER THE EASTERN PORTION OF THE FORECAST AREA
THROUGH SUNDAY MORNING. LIGHT SHOWER ACTIVITY IS EXPECTED.

BUILDING NORTHWEST FLOW THEN EXPECTED SUNDAY AFTERNOON AND EVENING
AS A RIDGE OF HIGH PRESSURE BUILDS OFF THE PACIFIC COAST. THIS
SYSTEM WILL BRING SOME MOISTURE INTO NORTHWESTERN WYOMING EARLY
MONDAY MORNING...MAINLY IMPACTING WESTERN AND NORTHERN WYOMING.

ANOTHER...MORE SIGNIFICANT PUSH OF MOISTURE WILL FOLLOW THAT SYSTEM
QUICKLY...WITH PRECIPITATION SPREADING INTO WESTERN WYOMING MONDAY
EVENING. ACTIVITY FROM THIS SYSTEM WILL LINGER THROUGH WEDNESDAY AS
ANOTHER PUSH COMES DOWN FROM THE NORTH AS WELL. THE ACTIVITY WILL
SPREAD TO INCLUDE MUCH OF THE FORECAST AREA. MODELS HAVE SOME
VARIATIONS ON THIS SYSTEM...WITH THE GFS REMAINING THE MOST
AGGRESSIVE MODEL. HOWEVER...ALL MODELS ARE IN FAIR AGREEMENT THAT
COVERAGE WILL INCREASE THROUGH WEDNESDAY MORNING.

CONDITIONS TO IMPROVE WEDNESDAY AFTERNOON AND EVENING. A BUILDING
RIDGE WILL HELP TO CLEAR OUT ACTIVITY...THOUGH SOME VERY LIGHT
ACTIVITY MAY REMAIN POSSIBLE ACROSS THE NORTHWEST THROUGH THURSDAY
AFTERNOON. DRY CONDITIONS EXPECTED BY FRIDAY MORNING...WHICH MAY NOT
LAST LONG.

&&

.AVIATION.../00Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

VFR CONDITIONS WILL PREVAIL THIS EVENING...WITH FOG LINGERING IN
THE BIGHORN BASIN NEAR KGEY. FOG WILL SPREAD THROUGHOUT THE
NIGHT...REACHING KWRL BY 10Z SATURDAY. N-NE SFC WINDS WILL
PREVAIL ACROSS THE AREA...WITH SOME LOWER CIGS EXPECTED ALONG THE
EAST SLOPES OF THE DIVIDE AND OTHER UPSLOPE FAVORED AREAS. MOST OF
THESE CIGS ARE EXPECTED TO REMAIN VFR...OBSCURING HIGHER MTNS.
CLEARING IS EXPECTED AFTER 12Z SATURDAY...WITH IMPROVING
CONDITIONS FROM NORTH TO SOUTH THROUGH THE DAY. THIS WILL BE
SHORT-LIVED...AS A COLD FRONT BEGINS TO IMPACT KCOD-KWRL WITH MVFR
CONDITIONS BY 23Z SATURDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

AN UPPER LEVEL LOW PRESSURE SYSTEM OVER THE FOUR CORNERS...WILL
CONTINUE TO PUSH UP MOISTURE INTO SOUTHERN WYOMING THROUGH THE
PERIOD...WITH CIGS EXPECTED TO GRADUALLY LOWER VCNTY AND SOUTH OF
INTERSTATE 80...WITH SOME ISOLD TO SCT -SHSN MOVING IN EARLY THIS
EVENING ALONG WITH LOCAL MVFR/IFR CONDITIONS. MVFR/IFR CONDITIONS ARE
EXPECTED TO BECOME MORE PREVALENT IN THIS AREA AFTER 00Z SATURDAY.
VFR CONDITIONS WILL RETURN TO THESE AREAS AFTER 15Z
SATURDAY...WITH INCREASING WESTERLY WINDS OF 15 TO 25 MPH BY 21Z.

NORTH OF INTERSTATE 80...VFR CONDITIONS WILL PREVAIL THROUGH THE
PERIOD.

&&

.FIRE WEATHER...

FIRE DANGER IS LOW FOR ALL AREAS...AND WILL REMAIN SO THROUGH NEXT
WEEK. MEASURABLE PRECIPITATION WILL NOT FALL ACROSS THE FORECAST
AREA UNTIL LATE SATURDAY INTO SUNDAY MORNING EAST OF THE DIVIDE.
FROM SUNDAY NIGHT THROUGH THE NEXT WORK WEEK...A SERIES OF
DISTURBANCES WILL RIDE THROUGH THE REGION...AFFECTING MAINLY THE
WESTERN AND NORTHERN DISPATCH ZONES. SATURDAY WILL SEE
IMPROVEMENT IN BOTH MIXING ABILITY AND DISPERSION...ESPECIALLY
EAST OF THE DIVIDE AND ACROSS THE SOUTHERN ZONES.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...LAVOIE
LONG TERM...BRANHAM
AVIATION...LAVOIE
FIRE WEATHER...LAVOIE







000
FXUS63 KUNR 302052
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
152 PM MST FRI JAN 30 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 151 PM MST FRI JAN 30 2015

WESTERN CONUS RIDGE WILL WEAKEN IN THE PERIOD...WITH A
STRONG NW FLOW IMPULSE FORCING AN ARCTIC FRONT THROUGH THE REGION
SATURDAY. THIS FEATURE WITH AN ASSOCIATED STRONG JET STREAK WILL
FORCE A PERIOD OF LIGHT SNOW OVER THE AREA MAINLY SAT NIGHT. IN
ADDITION...A SW CONUS UPPER LOW AND ITS ASSOCIATED DEEP MOISTURE WILL
SKIRT THE CENTRAL PLAINS...HELPING TO PIVOT THE LL BAROCLINIC ZONE
NEAR SCENTRAL SD...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-2 INCH
RANGE...HIGHEST ACROSS NW SD AND THE NORTHERN BH FOOTHILLS.

MILD CONDS IN PLACE ACROSS THE FA THIS AFTERNOON. HOWEVER...A
PASSING SHORTWAVE ACROSS THE SOUTHERN PRAIRIE PROVINCES OF CANADA IS
FORCING A COLD FRONT SOUTH INTO ND. THIS FRONT WILL PUSH SSW ACROSS
THE DAKOTAS...INCLUDING THE NORTHERN PORTION OF THE FA
TONIGHT...STALLING OVER THE BLACK HILLS SAT. A POTENT IMPULSE NOW
OVER SOUTHERN BC WILL QUICKLY ADVECT SE INTO THE REGION
SAT...SUPPORTING INCREASING LSA. THIS SYSTEM WILL BE ASSOCIATED WITH
A 120 KNOT JET STREAK...WITH THE LEFT EXIT REGION SPREADING OVER THE
FA. STRONG CONVERGENCE ASSOCIATED WITH AN EXPECTED ARCTIC
SURGE/STRONG LSA/AND ENHANCED LEFT EXIT FORCING WILL PRODUCE AMPLE
UVM...SUPPORTING SNOWS LATE SAT AFTERNOON INTO SATURDAY NIGHT. SNOW
WILL SPREAD SW ACROSS THE FA...WITH NW SD SEEING THE BEST
COLLOCATION OF THE AFOREMENTIONED FEATURES. ADDITIONAL UPSLOPE
ENHANCEMENT EXPECTED OVER THE NORTHERN BLACK HILLS FOOTHILLS. THESE
AREAS ARE EXPECTED TO SEE 1-2 INCHES WITH LOCALLY 3 POSSIBLE WHERE
FORCING PERSIST LONGEST. ADDITIONAL AND SEPARATE SNOWS LIKELY ACROSS
FAR EASTERN SCENTRAL SD WITH ENHANCEMENT FROM THE SKIRTING SOUTHERN
PLAINS SYSTEM MOISTURE PLUME. COLD AIR WILL SPREAD SOUTH INTO THE
REGION WITH TONIGHT/S FIRST FRONT...STALLING OVER THE BH SAT. THIS
WILL SUPPORT A LARGE TEMP SPREAD ACROSS THE FA SAT WITH 40S EXPECTED
OVER NE WY TO UPPER 20S ACROSS FAR NE PORTIONS OF THE FA. MODIFIED
ARCTIC AIR WILL SPREAD SOUTH INTO THE REGION SAT NIGHT WITH LOWS IN
THE SINGLE DIGITS MOST AREAS.


.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 151 PM MST FRI JAN 30 2015

SHORTWAVE ENERGY WILL CROSS THE NORTHERN PLAINS IN
NORTHWEST FLOW...BRINGING LIGHT SNOW TO PARTS OF THE AREA MONDAY
INTO TUESDAY. AN UPPER RIDGE IS PROGGED TO BUILD ACROSS THE ROCKIES
LATE NEXT WEEK...WITH DRY WEATHER EXPECTED.

THE TEMPERATURE FORECAST FOR NEXT WEEK REMAINS TRICKY AS SURFACE
FRONTAL BOUNDARY MEANDERS ACROSS THE CWA AT TIMES. UNDER A COLDER
AIRMASS...TEMPS ON SUNDAY WILL BE 10-20 DEGREES BELOW AVERAGE. FOR
THE REST OF THE EXTENDED...THE LATEST MODEL RUNS HAVE MUCH WARMER
TEMPS THAN PREVIOUSLY. THERE ARE STILL SOME TIMING ISSUES WITH THE
NEXT COLD FRONT THAT DIVES SOUTH TUESDAY...BUT THE GFS AND ECMWF
CONTINUE TO SHOW WARMER AIR MOVING BACK INTO THE REGION TOWARDS THE
END OF NEXT WEEK. WITH LOW CONFIDENCE IN MODEL TEMP
FORECASTS...COOLED TEMPS A BIT MONDAY THROUGH WEDNESDAY NIGHT TO
CURTAIL SUCH A DRASTIC CHANGE.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SATURDAY
ISSUED AT 151 PM MST FRI JAN 30 2015

VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY MORNING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...POJORLIE







000
FXUS63 KUNR 302052
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
152 PM MST FRI JAN 30 2015

.SHORT TERM...THIS EVENING THROUGH SATURDAY NIGHT
ISSUED AT 151 PM MST FRI JAN 30 2015

WESTERN CONUS RIDGE WILL WEAKEN IN THE PERIOD...WITH A
STRONG NW FLOW IMPULSE FORCING AN ARCTIC FRONT THROUGH THE REGION
SATURDAY. THIS FEATURE WITH AN ASSOCIATED STRONG JET STREAK WILL
FORCE A PERIOD OF LIGHT SNOW OVER THE AREA MAINLY SAT NIGHT. IN
ADDITION...A SW CONUS UPPER LOW AND ITS ASSOCIATED DEEP MOISTURE WILL
SKIRT THE CENTRAL PLAINS...HELPING TO PIVOT THE LL BAROCLINIC ZONE
NEAR SCENTRAL SD...SUPPORTING A SEPARATE AREA OF SNOW.
OVERALL...SNOW TOTALS WILL BE LIGHT...IN THE 1-2 INCH
RANGE...HIGHEST ACROSS NW SD AND THE NORTHERN BH FOOTHILLS.

MILD CONDS IN PLACE ACROSS THE FA THIS AFTERNOON. HOWEVER...A
PASSING SHORTWAVE ACROSS THE SOUTHERN PRAIRIE PROVINCES OF CANADA IS
FORCING A COLD FRONT SOUTH INTO ND. THIS FRONT WILL PUSH SSW ACROSS
THE DAKOTAS...INCLUDING THE NORTHERN PORTION OF THE FA
TONIGHT...STALLING OVER THE BLACK HILLS SAT. A POTENT IMPULSE NOW
OVER SOUTHERN BC WILL QUICKLY ADVECT SE INTO THE REGION
SAT...SUPPORTING INCREASING LSA. THIS SYSTEM WILL BE ASSOCIATED WITH
A 120 KNOT JET STREAK...WITH THE LEFT EXIT REGION SPREADING OVER THE
FA. STRONG CONVERGENCE ASSOCIATED WITH AN EXPECTED ARCTIC
SURGE/STRONG LSA/AND ENHANCED LEFT EXIT FORCING WILL PRODUCE AMPLE
UVM...SUPPORTING SNOWS LATE SAT AFTERNOON INTO SATURDAY NIGHT. SNOW
WILL SPREAD SW ACROSS THE FA...WITH NW SD SEEING THE BEST
COLLOCATION OF THE AFOREMENTIONED FEATURES. ADDITIONAL UPSLOPE
ENHANCEMENT EXPECTED OVER THE NORTHERN BLACK HILLS FOOTHILLS. THESE
AREAS ARE EXPECTED TO SEE 1-2 INCHES WITH LOCALLY 3 POSSIBLE WHERE
FORCING PERSIST LONGEST. ADDITIONAL AND SEPARATE SNOWS LIKELY ACROSS
FAR EASTERN SCENTRAL SD WITH ENHANCEMENT FROM THE SKIRTING SOUTHERN
PLAINS SYSTEM MOISTURE PLUME. COLD AIR WILL SPREAD SOUTH INTO THE
REGION WITH TONIGHT/S FIRST FRONT...STALLING OVER THE BH SAT. THIS
WILL SUPPORT A LARGE TEMP SPREAD ACROSS THE FA SAT WITH 40S EXPECTED
OVER NE WY TO UPPER 20S ACROSS FAR NE PORTIONS OF THE FA. MODIFIED
ARCTIC AIR WILL SPREAD SOUTH INTO THE REGION SAT NIGHT WITH LOWS IN
THE SINGLE DIGITS MOST AREAS.


.LONG TERM...SUNDAY THROUGH FRIDAY
ISSUED AT 151 PM MST FRI JAN 30 2015

SHORTWAVE ENERGY WILL CROSS THE NORTHERN PLAINS IN
NORTHWEST FLOW...BRINGING LIGHT SNOW TO PARTS OF THE AREA MONDAY
INTO TUESDAY. AN UPPER RIDGE IS PROGGED TO BUILD ACROSS THE ROCKIES
LATE NEXT WEEK...WITH DRY WEATHER EXPECTED.

THE TEMPERATURE FORECAST FOR NEXT WEEK REMAINS TRICKY AS SURFACE
FRONTAL BOUNDARY MEANDERS ACROSS THE CWA AT TIMES. UNDER A COLDER
AIRMASS...TEMPS ON SUNDAY WILL BE 10-20 DEGREES BELOW AVERAGE. FOR
THE REST OF THE EXTENDED...THE LATEST MODEL RUNS HAVE MUCH WARMER
TEMPS THAN PREVIOUSLY. THERE ARE STILL SOME TIMING ISSUES WITH THE
NEXT COLD FRONT THAT DIVES SOUTH TUESDAY...BUT THE GFS AND ECMWF
CONTINUE TO SHOW WARMER AIR MOVING BACK INTO THE REGION TOWARDS THE
END OF NEXT WEEK. WITH LOW CONFIDENCE IN MODEL TEMP
FORECASTS...COOLED TEMPS A BIT MONDAY THROUGH WEDNESDAY NIGHT TO
CURTAIL SUCH A DRASTIC CHANGE.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SATURDAY
ISSUED AT 151 PM MST FRI JAN 30 2015

VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY MORNING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JC
LONG TERM...POJORLIE
AVIATION...POJORLIE






000
FXUS65 KCYS 301822 AAA
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
1122 AM MST FRI JAN 30 2015

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 229 AM MST FRI JAN 30 2015

TODAY...DESPITE BROKEN TO OVERCAST SKIES OVER CARBON COUNTY...WE
MAY SEE SOME AREAS OF FOG THERE WITH TEMPERATURE AND DEWPOINT
SPREADS AROUND 3 DEGREES. WILL SEE INCREASING MIDDLE AND HIGH
CLOUDS AHEAD OF THE SHORTWAVE TROUGH ALOFT APPROACHING FROM
SOUTHERN ARIZONA...WITH A FEW SNOW SHOWERS OVER OUR SNOWY AND
SIERRA MADRE RANGES...DRY ELSEWHERE.

TONIGHT...AREAS OF FOG WILL INCREASE IN COVERAGE AS THE LOW LEVELS
SATURATE...THOUGH THE FOG COVERAGE WILL BE LIMITED SOMEWHAT BY
THE AMOUNT OF MIDDLE AND HIGH LEVEL CLOUDS. WITH SOME WEAK
SHORTWAVE TROUGH ALOFT ENERGY...UPSLOPE AND SATURATED LOW
LEVELS...EXPECT A CHANCE OF SNOW SOUTH OF A RAWLINS TO CHEYENNE
LINE.

SATURDAY...NEXT FAST MOVING SHORTWAVE TROUGH ALOFT...AN ALBERTA
TYPE CLIPPER...WILL MOVE TO NORTHEAST WYOMING SENDING THE NEXT
ARCTIC COLD FRONT SOUTH ACROSS OUR NORTHERN COUNTIES. ENOUGH LOW
AND MID LEVEL MOISTURE...NORTHERLY UPSLOPE AND WEAK UPWARD
VERTICAL MOTION TO PRODUCE A CHANCE OF LIGHT SNOW SOUTH OF A
RAWLINS TO SCOTTSBLUFF LINE.

SATURDAY NIGHT...STRONG COLD AIR ADVECTION AND CYCLONIC FLOW ALOFT
WILL WRING OUT A CHANCE OF LIGHT SNOW BUT WITH MINIMAL ACCUMULATIONS
DUE TO LACK OF LOW AND MID LEVEL MOISTURE.

SUNDAY...BREEZY AND COLD DAY WITH FAST NORTH NORTHWEST FLOW ALOFT
AND DECENT COLD AIR ADVECTION CONTINUING. HIGH TEMPERATURES WILL
STRUGGLE TO REACH FREEZING AT MOST LOCATIONS DESPITE SOME
SUNSHINE.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 229 AM MST FRI JAN 30 2015

AN UPPER LEVEL RIDGE WILL BUILD OVER THE ROCKIES SUNDAY NIGHT INTO
MONDAY WITH STRONG WAA OCCURRING OVER THE CWA THROUGH THIS TIME.
LOOKING AT TEMPS SPIKING INTO THE 40S AND 50S FOR MONDAY. SHORTWAVE
ENERGY ON THE NOSE OF A 100 KT JET WILL MOVE QUICKLY ATOP THE
RIDGE AND OVER THE ROCKIES AS WELL AND THE LEESIDE PRESSURE TROUGH
WILL RAPIDLY DEEPEN IN ADVANCE OF THIS WAVE. MODELS SHOW WINDS IN
THE 800-700 MB LAYER OVER SOUTHEAST WYOMING INCREASING TO 50+ KTS
LATE SUNDAY NIGHT AS THE LLVL PRESSURE GRADIENT STRENGTHENS. WITH
WAA IN PLACE...LIKELY TO SEE STRONG WINDS BECOME TRAPPED NEAR THE
SURFACE IN THE WIND PRONE AREAS OF SOUTHEAST WYOMING. UPSLOPE FLOW
ALONG THE WESTERN SLOPES WILL STRENGTHEN AS THESE WINDS DEVELOP
AND WILL COMBINE WITH INCREASED PACIFIC MOISTURE TO BRING A GOOD
CHANCE FOR OROGRAPHIC SNOW DURING THIS TIME AS WELL. THE LLVL
PRESSURE GRADIENT WILL RELAX SLIGHTLY ON MONDAY EVENING AS THE
INITIAL WAVE SHIFTS EAST...BUT ANOTHER AND SOMEWHAT STRONGER VORT
MAX WILL MOVE INTO THE NORTHERN ROCKIES MONDAY NIGHT AND WILL
REINTENSIFY THE GRADIENT. STILL THINKING THE WIND PRONE AREAS WILL
SEE A SECOND ROUND OF HIGH WINDS WHILE OROGRAPHIC SNOW INTENSIFIES
OVER THE MOUNTAINS MONDAY NIGHT THROUGH TUESDAY MORNING. HIGH
WINDS COULD EXPAND FURTHER EAST ONTO THE PLAINS LATE TUESDAY
MORNING WITH NEARLY 60 KTS PROGGED AT 750 MB AND ONLY PATCHY
CIRRUS OVERHEAD TO POTENTIALLY INHIBIT MIXING. CANT RULE OUT A FEW
SHOWERS MAINLY OVER THE NORTHERN ZONES FROM CONVERSE TO BOX BUTTE
COUNTIES TUESDAY MORNING AS THE VORT MOVES ACROSS THE NORTHERN
ROCKIES AND AN ASSOCIATED COLD FRONT STALLS OVER THIS AREA.

BEYOND TUESDAY...CONFIDENCE IS LOW WHETHER HIGH WINDS WILL BE
REALIZED IN THE WIND PRONE AREAS ONCE AGAIN WEDNESDAY
MORNING...OR IF THE COLD FRONT WILL MOVE SOUTH THRU THE PLAINS
EARLY ENOUGH TO SHUT OFF THE HIGH WINDS AND BRING RAIN/SNOW TO
THE CWA INSTEAD. THE 00Z GFS...EC AND GEM ALL SHOW VARIED
SOLUTIONS WITH THE SOUTHWARD SURGE OF THE FRONT...WITH THE GEM
NEARLY 12HRS FASTER THAN THE GFS...AND THE EC 6HRS SLOWER THAN THE
GFS. WITH THIS LEVEL OF VARIABILITY ON TIMING...WILL TREND TOWARD
A MIDDLE GROUND SOLUTION FOR NOW WHICH MEANS WINDY CONDITIONS WILL
PREVAIL THROUGH WEDNESDAY MORNING BUT WILL NOT QUITE REACH HIGH
WIND LEVELS. WILL KEEP MAINLY SLIGHT CHANCE POPS TUESDAY NIGHT
INTO WEDNESDAY MORNING FOR MUCH OF THE CWA EXCEPT IN THE
MOUNTAINS WHERE CHANCE POPS ARE REASONABLE. MOSTLY DRY CONDITIONS
AND LESS WIND WILL PREVAIL FOR THURSDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1114 AM MST FRI JAN 30 2015

CURRENTLY GETTING MVFR CATEGORY OBSERVED AT RAWLINS WY WHERE LIGHT
SNOW SHOWERS ARE PRODUCING VISIBILITIES DOWN TO 2SM...BUT THAT SHOULD
NOT BE A PREVAILING CONDITION THROUGH THE AFTERNOON WITH MVFR
CEILINGS BKN 2000FT AGL EXPECTED. OTHERWISE REST OF FORECAST AREA
EXPECTED TO SEE VFR CONDITIONS THROUGH THE EVENING WITH LOWERING
CEILINGS TO MVFR ACROSS THE ALLIANCE AND SIDNEY NE AREAS LATER
TONIGHT WITH LIGHT SOUTHERLY FLOW. MAY GET SOME PATCHY FOG IN
SPOTS TONIGHT (PARTICULARLY WHERE ANY LIGHT UPSLOW DEVELOPS). WILL
ALSO SEE A CHANCE OF LIGHT SNOW WITH MVFR CATEGORY CONDITIONS
POSSIBLE RAWLINS AND LARAMIE CLOSER TO WHERE ORAGRAPHICALLY
INDUCED SNOW SHOWERS IN THE MOUNTAINS ARE EXPECTED...BUT OTHERWISE
NO MAJOR CONCERNS THROUGH TOMORROW MORNING AND WE DONT EXPECT TO
SEE PREVAILING REDUCED VISIBILITIES DUE TO SNOW FOR THOSE
LOCATIONS THROUGH MORNING. THE HIGHER SNOW CHANCES THROUGH MORNING
ARE EXPECTED TO BE TO OUR SOUTH IN THE COLORADO MOUNTAINS.

&&

.FIRE WEATHER...
ISSUED AT 229 AM MST FRI JAN 30 2015

MINIMAL CONCERNS. A STRONG ARCTIC COLD FRONT WILL SWEEP QUICKLY
NORTH TO SOUTH ACROSS THE DISTRICT ON SATURDAY...USHERING IN
COLDER TEMPERATURES FOR SUNDAY. WARMING TEMPERATURES FOR MONDAY
AND TUESDAY BEFORE ANOTHER COLD FRONT BRINGS COOLER TEMPERATURES
FOR WEDNESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RUBIN
LONG TERM...RJM
AVIATION...JG
FIRE WEATHER...RUBIN



000
FXUS65 KCYS 301822 AAA
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
1122 AM MST FRI JAN 30 2015

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 229 AM MST FRI JAN 30 2015

TODAY...DESPITE BROKEN TO OVERCAST SKIES OVER CARBON COUNTY...WE
MAY SEE SOME AREAS OF FOG THERE WITH TEMPERATURE AND DEWPOINT
SPREADS AROUND 3 DEGREES. WILL SEE INCREASING MIDDLE AND HIGH
CLOUDS AHEAD OF THE SHORTWAVE TROUGH ALOFT APPROACHING FROM
SOUTHERN ARIZONA...WITH A FEW SNOW SHOWERS OVER OUR SNOWY AND
SIERRA MADRE RANGES...DRY ELSEWHERE.

TONIGHT...AREAS OF FOG WILL INCREASE IN COVERAGE AS THE LOW LEVELS
SATURATE...THOUGH THE FOG COVERAGE WILL BE LIMITED SOMEWHAT BY
THE AMOUNT OF MIDDLE AND HIGH LEVEL CLOUDS. WITH SOME WEAK
SHORTWAVE TROUGH ALOFT ENERGY...UPSLOPE AND SATURATED LOW
LEVELS...EXPECT A CHANCE OF SNOW SOUTH OF A RAWLINS TO CHEYENNE
LINE.

SATURDAY...NEXT FAST MOVING SHORTWAVE TROUGH ALOFT...AN ALBERTA
TYPE CLIPPER...WILL MOVE TO NORTHEAST WYOMING SENDING THE NEXT
ARCTIC COLD FRONT SOUTH ACROSS OUR NORTHERN COUNTIES. ENOUGH LOW
AND MID LEVEL MOISTURE...NORTHERLY UPSLOPE AND WEAK UPWARD
VERTICAL MOTION TO PRODUCE A CHANCE OF LIGHT SNOW SOUTH OF A
RAWLINS TO SCOTTSBLUFF LINE.

SATURDAY NIGHT...STRONG COLD AIR ADVECTION AND CYCLONIC FLOW ALOFT
WILL WRING OUT A CHANCE OF LIGHT SNOW BUT WITH MINIMAL ACCUMULATIONS
DUE TO LACK OF LOW AND MID LEVEL MOISTURE.

SUNDAY...BREEZY AND COLD DAY WITH FAST NORTH NORTHWEST FLOW ALOFT
AND DECENT COLD AIR ADVECTION CONTINUING. HIGH TEMPERATURES WILL
STRUGGLE TO REACH FREEZING AT MOST LOCATIONS DESPITE SOME
SUNSHINE.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 229 AM MST FRI JAN 30 2015

AN UPPER LEVEL RIDGE WILL BUILD OVER THE ROCKIES SUNDAY NIGHT INTO
MONDAY WITH STRONG WAA OCCURRING OVER THE CWA THROUGH THIS TIME.
LOOKING AT TEMPS SPIKING INTO THE 40S AND 50S FOR MONDAY. SHORTWAVE
ENERGY ON THE NOSE OF A 100 KT JET WILL MOVE QUICKLY ATOP THE
RIDGE AND OVER THE ROCKIES AS WELL AND THE LEESIDE PRESSURE TROUGH
WILL RAPIDLY DEEPEN IN ADVANCE OF THIS WAVE. MODELS SHOW WINDS IN
THE 800-700 MB LAYER OVER SOUTHEAST WYOMING INCREASING TO 50+ KTS
LATE SUNDAY NIGHT AS THE LLVL PRESSURE GRADIENT STRENGTHENS. WITH
WAA IN PLACE...LIKELY TO SEE STRONG WINDS BECOME TRAPPED NEAR THE
SURFACE IN THE WIND PRONE AREAS OF SOUTHEAST WYOMING. UPSLOPE FLOW
ALONG THE WESTERN SLOPES WILL STRENGTHEN AS THESE WINDS DEVELOP
AND WILL COMBINE WITH INCREASED PACIFIC MOISTURE TO BRING A GOOD
CHANCE FOR OROGRAPHIC SNOW DURING THIS TIME AS WELL. THE LLVL
PRESSURE GRADIENT WILL RELAX SLIGHTLY ON MONDAY EVENING AS THE
INITIAL WAVE SHIFTS EAST...BUT ANOTHER AND SOMEWHAT STRONGER VORT
MAX WILL MOVE INTO THE NORTHERN ROCKIES MONDAY NIGHT AND WILL
REINTENSIFY THE GRADIENT. STILL THINKING THE WIND PRONE AREAS WILL
SEE A SECOND ROUND OF HIGH WINDS WHILE OROGRAPHIC SNOW INTENSIFIES
OVER THE MOUNTAINS MONDAY NIGHT THROUGH TUESDAY MORNING. HIGH
WINDS COULD EXPAND FURTHER EAST ONTO THE PLAINS LATE TUESDAY
MORNING WITH NEARLY 60 KTS PROGGED AT 750 MB AND ONLY PATCHY
CIRRUS OVERHEAD TO POTENTIALLY INHIBIT MIXING. CANT RULE OUT A FEW
SHOWERS MAINLY OVER THE NORTHERN ZONES FROM CONVERSE TO BOX BUTTE
COUNTIES TUESDAY MORNING AS THE VORT MOVES ACROSS THE NORTHERN
ROCKIES AND AN ASSOCIATED COLD FRONT STALLS OVER THIS AREA.

BEYOND TUESDAY...CONFIDENCE IS LOW WHETHER HIGH WINDS WILL BE
REALIZED IN THE WIND PRONE AREAS ONCE AGAIN WEDNESDAY
MORNING...OR IF THE COLD FRONT WILL MOVE SOUTH THRU THE PLAINS
EARLY ENOUGH TO SHUT OFF THE HIGH WINDS AND BRING RAIN/SNOW TO
THE CWA INSTEAD. THE 00Z GFS...EC AND GEM ALL SHOW VARIED
SOLUTIONS WITH THE SOUTHWARD SURGE OF THE FRONT...WITH THE GEM
NEARLY 12HRS FASTER THAN THE GFS...AND THE EC 6HRS SLOWER THAN THE
GFS. WITH THIS LEVEL OF VARIABILITY ON TIMING...WILL TREND TOWARD
A MIDDLE GROUND SOLUTION FOR NOW WHICH MEANS WINDY CONDITIONS WILL
PREVAIL THROUGH WEDNESDAY MORNING BUT WILL NOT QUITE REACH HIGH
WIND LEVELS. WILL KEEP MAINLY SLIGHT CHANCE POPS TUESDAY NIGHT
INTO WEDNESDAY MORNING FOR MUCH OF THE CWA EXCEPT IN THE
MOUNTAINS WHERE CHANCE POPS ARE REASONABLE. MOSTLY DRY CONDITIONS
AND LESS WIND WILL PREVAIL FOR THURSDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1114 AM MST FRI JAN 30 2015

CURRENTLY GETTING MVFR CATEGORY OBSERVED AT RAWLINS WY WHERE LIGHT
SNOW SHOWERS ARE PRODUCING VISIBILITIES DOWN TO 2SM...BUT THAT SHOULD
NOT BE A PREVAILING CONDITION THROUGH THE AFTERNOON WITH MVFR
CEILINGS BKN 2000FT AGL EXPECTED. OTHERWISE REST OF FORECAST AREA
EXPECTED TO SEE VFR CONDITIONS THROUGH THE EVENING WITH LOWERING
CEILINGS TO MVFR ACROSS THE ALLIANCE AND SIDNEY NE AREAS LATER
TONIGHT WITH LIGHT SOUTHERLY FLOW. MAY GET SOME PATCHY FOG IN
SPOTS TONIGHT (PARTICULARLY WHERE ANY LIGHT UPSLOW DEVELOPS). WILL
ALSO SEE A CHANCE OF LIGHT SNOW WITH MVFR CATEGORY CONDITIONS
POSSIBLE RAWLINS AND LARAMIE CLOSER TO WHERE ORAGRAPHICALLY
INDUCED SNOW SHOWERS IN THE MOUNTAINS ARE EXPECTED...BUT OTHERWISE
NO MAJOR CONCERNS THROUGH TOMORROW MORNING AND WE DONT EXPECT TO
SEE PREVAILING REDUCED VISIBILITIES DUE TO SNOW FOR THOSE
LOCATIONS THROUGH MORNING. THE HIGHER SNOW CHANCES THROUGH MORNING
ARE EXPECTED TO BE TO OUR SOUTH IN THE COLORADO MOUNTAINS.

&&

.FIRE WEATHER...
ISSUED AT 229 AM MST FRI JAN 30 2015

MINIMAL CONCERNS. A STRONG ARCTIC COLD FRONT WILL SWEEP QUICKLY
NORTH TO SOUTH ACROSS THE DISTRICT ON SATURDAY...USHERING IN
COLDER TEMPERATURES FOR SUNDAY. WARMING TEMPERATURES FOR MONDAY
AND TUESDAY BEFORE ANOTHER COLD FRONT BRINGS COOLER TEMPERATURES
FOR WEDNESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RUBIN
LONG TERM...RJM
AVIATION...JG
FIRE WEATHER...RUBIN



000
FXUS65 KCYS 301822 AAA
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
1122 AM MST FRI JAN 30 2015

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 229 AM MST FRI JAN 30 2015

TODAY...DESPITE BROKEN TO OVERCAST SKIES OVER CARBON COUNTY...WE
MAY SEE SOME AREAS OF FOG THERE WITH TEMPERATURE AND DEWPOINT
SPREADS AROUND 3 DEGREES. WILL SEE INCREASING MIDDLE AND HIGH
CLOUDS AHEAD OF THE SHORTWAVE TROUGH ALOFT APPROACHING FROM
SOUTHERN ARIZONA...WITH A FEW SNOW SHOWERS OVER OUR SNOWY AND
SIERRA MADRE RANGES...DRY ELSEWHERE.

TONIGHT...AREAS OF FOG WILL INCREASE IN COVERAGE AS THE LOW LEVELS
SATURATE...THOUGH THE FOG COVERAGE WILL BE LIMITED SOMEWHAT BY
THE AMOUNT OF MIDDLE AND HIGH LEVEL CLOUDS. WITH SOME WEAK
SHORTWAVE TROUGH ALOFT ENERGY...UPSLOPE AND SATURATED LOW
LEVELS...EXPECT A CHANCE OF SNOW SOUTH OF A RAWLINS TO CHEYENNE
LINE.

SATURDAY...NEXT FAST MOVING SHORTWAVE TROUGH ALOFT...AN ALBERTA
TYPE CLIPPER...WILL MOVE TO NORTHEAST WYOMING SENDING THE NEXT
ARCTIC COLD FRONT SOUTH ACROSS OUR NORTHERN COUNTIES. ENOUGH LOW
AND MID LEVEL MOISTURE...NORTHERLY UPSLOPE AND WEAK UPWARD
VERTICAL MOTION TO PRODUCE A CHANCE OF LIGHT SNOW SOUTH OF A
RAWLINS TO SCOTTSBLUFF LINE.

SATURDAY NIGHT...STRONG COLD AIR ADVECTION AND CYCLONIC FLOW ALOFT
WILL WRING OUT A CHANCE OF LIGHT SNOW BUT WITH MINIMAL ACCUMULATIONS
DUE TO LACK OF LOW AND MID LEVEL MOISTURE.

SUNDAY...BREEZY AND COLD DAY WITH FAST NORTH NORTHWEST FLOW ALOFT
AND DECENT COLD AIR ADVECTION CONTINUING. HIGH TEMPERATURES WILL
STRUGGLE TO REACH FREEZING AT MOST LOCATIONS DESPITE SOME
SUNSHINE.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 229 AM MST FRI JAN 30 2015

AN UPPER LEVEL RIDGE WILL BUILD OVER THE ROCKIES SUNDAY NIGHT INTO
MONDAY WITH STRONG WAA OCCURRING OVER THE CWA THROUGH THIS TIME.
LOOKING AT TEMPS SPIKING INTO THE 40S AND 50S FOR MONDAY. SHORTWAVE
ENERGY ON THE NOSE OF A 100 KT JET WILL MOVE QUICKLY ATOP THE
RIDGE AND OVER THE ROCKIES AS WELL AND THE LEESIDE PRESSURE TROUGH
WILL RAPIDLY DEEPEN IN ADVANCE OF THIS WAVE. MODELS SHOW WINDS IN
THE 800-700 MB LAYER OVER SOUTHEAST WYOMING INCREASING TO 50+ KTS
LATE SUNDAY NIGHT AS THE LLVL PRESSURE GRADIENT STRENGTHENS. WITH
WAA IN PLACE...LIKELY TO SEE STRONG WINDS BECOME TRAPPED NEAR THE
SURFACE IN THE WIND PRONE AREAS OF SOUTHEAST WYOMING. UPSLOPE FLOW
ALONG THE WESTERN SLOPES WILL STRENGTHEN AS THESE WINDS DEVELOP
AND WILL COMBINE WITH INCREASED PACIFIC MOISTURE TO BRING A GOOD
CHANCE FOR OROGRAPHIC SNOW DURING THIS TIME AS WELL. THE LLVL
PRESSURE GRADIENT WILL RELAX SLIGHTLY ON MONDAY EVENING AS THE
INITIAL WAVE SHIFTS EAST...BUT ANOTHER AND SOMEWHAT STRONGER VORT
MAX WILL MOVE INTO THE NORTHERN ROCKIES MONDAY NIGHT AND WILL
REINTENSIFY THE GRADIENT. STILL THINKING THE WIND PRONE AREAS WILL
SEE A SECOND ROUND OF HIGH WINDS WHILE OROGRAPHIC SNOW INTENSIFIES
OVER THE MOUNTAINS MONDAY NIGHT THROUGH TUESDAY MORNING. HIGH
WINDS COULD EXPAND FURTHER EAST ONTO THE PLAINS LATE TUESDAY
MORNING WITH NEARLY 60 KTS PROGGED AT 750 MB AND ONLY PATCHY
CIRRUS OVERHEAD TO POTENTIALLY INHIBIT MIXING. CANT RULE OUT A FEW
SHOWERS MAINLY OVER THE NORTHERN ZONES FROM CONVERSE TO BOX BUTTE
COUNTIES TUESDAY MORNING AS THE VORT MOVES ACROSS THE NORTHERN
ROCKIES AND AN ASSOCIATED COLD FRONT STALLS OVER THIS AREA.

BEYOND TUESDAY...CONFIDENCE IS LOW WHETHER HIGH WINDS WILL BE
REALIZED IN THE WIND PRONE AREAS ONCE AGAIN WEDNESDAY
MORNING...OR IF THE COLD FRONT WILL MOVE SOUTH THRU THE PLAINS
EARLY ENOUGH TO SHUT OFF THE HIGH WINDS AND BRING RAIN/SNOW TO
THE CWA INSTEAD. THE 00Z GFS...EC AND GEM ALL SHOW VARIED
SOLUTIONS WITH THE SOUTHWARD SURGE OF THE FRONT...WITH THE GEM
NEARLY 12HRS FASTER THAN THE GFS...AND THE EC 6HRS SLOWER THAN THE
GFS. WITH THIS LEVEL OF VARIABILITY ON TIMING...WILL TREND TOWARD
A MIDDLE GROUND SOLUTION FOR NOW WHICH MEANS WINDY CONDITIONS WILL
PREVAIL THROUGH WEDNESDAY MORNING BUT WILL NOT QUITE REACH HIGH
WIND LEVELS. WILL KEEP MAINLY SLIGHT CHANCE POPS TUESDAY NIGHT
INTO WEDNESDAY MORNING FOR MUCH OF THE CWA EXCEPT IN THE
MOUNTAINS WHERE CHANCE POPS ARE REASONABLE. MOSTLY DRY CONDITIONS
AND LESS WIND WILL PREVAIL FOR THURSDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1114 AM MST FRI JAN 30 2015

CURRENTLY GETTING MVFR CATEGORY OBSERVED AT RAWLINS WY WHERE LIGHT
SNOW SHOWERS ARE PRODUCING VISIBILITIES DOWN TO 2SM...BUT THAT SHOULD
NOT BE A PREVAILING CONDITION THROUGH THE AFTERNOON WITH MVFR
CEILINGS BKN 2000FT AGL EXPECTED. OTHERWISE REST OF FORECAST AREA
EXPECTED TO SEE VFR CONDITIONS THROUGH THE EVENING WITH LOWERING
CEILINGS TO MVFR ACROSS THE ALLIANCE AND SIDNEY NE AREAS LATER
TONIGHT WITH LIGHT SOUTHERLY FLOW. MAY GET SOME PATCHY FOG IN
SPOTS TONIGHT (PARTICULARLY WHERE ANY LIGHT UPSLOW DEVELOPS). WILL
ALSO SEE A CHANCE OF LIGHT SNOW WITH MVFR CATEGORY CONDITIONS
POSSIBLE RAWLINS AND LARAMIE CLOSER TO WHERE ORAGRAPHICALLY
INDUCED SNOW SHOWERS IN THE MOUNTAINS ARE EXPECTED...BUT OTHERWISE
NO MAJOR CONCERNS THROUGH TOMORROW MORNING AND WE DONT EXPECT TO
SEE PREVAILING REDUCED VISIBILITIES DUE TO SNOW FOR THOSE
LOCATIONS THROUGH MORNING. THE HIGHER SNOW CHANCES THROUGH MORNING
ARE EXPECTED TO BE TO OUR SOUTH IN THE COLORADO MOUNTAINS.

&&

.FIRE WEATHER...
ISSUED AT 229 AM MST FRI JAN 30 2015

MINIMAL CONCERNS. A STRONG ARCTIC COLD FRONT WILL SWEEP QUICKLY
NORTH TO SOUTH ACROSS THE DISTRICT ON SATURDAY...USHERING IN
COLDER TEMPERATURES FOR SUNDAY. WARMING TEMPERATURES FOR MONDAY
AND TUESDAY BEFORE ANOTHER COLD FRONT BRINGS COOLER TEMPERATURES
FOR WEDNESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RUBIN
LONG TERM...RJM
AVIATION...JG
FIRE WEATHER...RUBIN



000
FXUS65 KCYS 301822 AAA
AFDCYS

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHEYENNE WY
1122 AM MST FRI JAN 30 2015

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 229 AM MST FRI JAN 30 2015

TODAY...DESPITE BROKEN TO OVERCAST SKIES OVER CARBON COUNTY...WE
MAY SEE SOME AREAS OF FOG THERE WITH TEMPERATURE AND DEWPOINT
SPREADS AROUND 3 DEGREES. WILL SEE INCREASING MIDDLE AND HIGH
CLOUDS AHEAD OF THE SHORTWAVE TROUGH ALOFT APPROACHING FROM
SOUTHERN ARIZONA...WITH A FEW SNOW SHOWERS OVER OUR SNOWY AND
SIERRA MADRE RANGES...DRY ELSEWHERE.

TONIGHT...AREAS OF FOG WILL INCREASE IN COVERAGE AS THE LOW LEVELS
SATURATE...THOUGH THE FOG COVERAGE WILL BE LIMITED SOMEWHAT BY
THE AMOUNT OF MIDDLE AND HIGH LEVEL CLOUDS. WITH SOME WEAK
SHORTWAVE TROUGH ALOFT ENERGY...UPSLOPE AND SATURATED LOW
LEVELS...EXPECT A CHANCE OF SNOW SOUTH OF A RAWLINS TO CHEYENNE
LINE.

SATURDAY...NEXT FAST MOVING SHORTWAVE TROUGH ALOFT...AN ALBERTA
TYPE CLIPPER...WILL MOVE TO NORTHEAST WYOMING SENDING THE NEXT
ARCTIC COLD FRONT SOUTH ACROSS OUR NORTHERN COUNTIES. ENOUGH LOW
AND MID LEVEL MOISTURE...NORTHERLY UPSLOPE AND WEAK UPWARD
VERTICAL MOTION TO PRODUCE A CHANCE OF LIGHT SNOW SOUTH OF A
RAWLINS TO SCOTTSBLUFF LINE.

SATURDAY NIGHT...STRONG COLD AIR ADVECTION AND CYCLONIC FLOW ALOFT
WILL WRING OUT A CHANCE OF LIGHT SNOW BUT WITH MINIMAL ACCUMULATIONS
DUE TO LACK OF LOW AND MID LEVEL MOISTURE.

SUNDAY...BREEZY AND COLD DAY WITH FAST NORTH NORTHWEST FLOW ALOFT
AND DECENT COLD AIR ADVECTION CONTINUING. HIGH TEMPERATURES WILL
STRUGGLE TO REACH FREEZING AT MOST LOCATIONS DESPITE SOME
SUNSHINE.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 229 AM MST FRI JAN 30 2015

AN UPPER LEVEL RIDGE WILL BUILD OVER THE ROCKIES SUNDAY NIGHT INTO
MONDAY WITH STRONG WAA OCCURRING OVER THE CWA THROUGH THIS TIME.
LOOKING AT TEMPS SPIKING INTO THE 40S AND 50S FOR MONDAY. SHORTWAVE
ENERGY ON THE NOSE OF A 100 KT JET WILL MOVE QUICKLY ATOP THE
RIDGE AND OVER THE ROCKIES AS WELL AND THE LEESIDE PRESSURE TROUGH
WILL RAPIDLY DEEPEN IN ADVANCE OF THIS WAVE. MODELS SHOW WINDS IN
THE 800-700 MB LAYER OVER SOUTHEAST WYOMING INCREASING TO 50+ KTS
LATE SUNDAY NIGHT AS THE LLVL PRESSURE GRADIENT STRENGTHENS. WITH
WAA IN PLACE...LIKELY TO SEE STRONG WINDS BECOME TRAPPED NEAR THE
SURFACE IN THE WIND PRONE AREAS OF SOUTHEAST WYOMING. UPSLOPE FLOW
ALONG THE WESTERN SLOPES WILL STRENGTHEN AS THESE WINDS DEVELOP
AND WILL COMBINE WITH INCREASED PACIFIC MOISTURE TO BRING A GOOD
CHANCE FOR OROGRAPHIC SNOW DURING THIS TIME AS WELL. THE LLVL
PRESSURE GRADIENT WILL RELAX SLIGHTLY ON MONDAY EVENING AS THE
INITIAL WAVE SHIFTS EAST...BUT ANOTHER AND SOMEWHAT STRONGER VORT
MAX WILL MOVE INTO THE NORTHERN ROCKIES MONDAY NIGHT AND WILL
REINTENSIFY THE GRADIENT. STILL THINKING THE WIND PRONE AREAS WILL
SEE A SECOND ROUND OF HIGH WINDS WHILE OROGRAPHIC SNOW INTENSIFIES
OVER THE MOUNTAINS MONDAY NIGHT THROUGH TUESDAY MORNING. HIGH
WINDS COULD EXPAND FURTHER EAST ONTO THE PLAINS LATE TUESDAY
MORNING WITH NEARLY 60 KTS PROGGED AT 750 MB AND ONLY PATCHY
CIRRUS OVERHEAD TO POTENTIALLY INHIBIT MIXING. CANT RULE OUT A FEW
SHOWERS MAINLY OVER THE NORTHERN ZONES FROM CONVERSE TO BOX BUTTE
COUNTIES TUESDAY MORNING AS THE VORT MOVES ACROSS THE NORTHERN
ROCKIES AND AN ASSOCIATED COLD FRONT STALLS OVER THIS AREA.

BEYOND TUESDAY...CONFIDENCE IS LOW WHETHER HIGH WINDS WILL BE
REALIZED IN THE WIND PRONE AREAS ONCE AGAIN WEDNESDAY
MORNING...OR IF THE COLD FRONT WILL MOVE SOUTH THRU THE PLAINS
EARLY ENOUGH TO SHUT OFF THE HIGH WINDS AND BRING RAIN/SNOW TO
THE CWA INSTEAD. THE 00Z GFS...EC AND GEM ALL SHOW VARIED
SOLUTIONS WITH THE SOUTHWARD SURGE OF THE FRONT...WITH THE GEM
NEARLY 12HRS FASTER THAN THE GFS...AND THE EC 6HRS SLOWER THAN THE
GFS. WITH THIS LEVEL OF VARIABILITY ON TIMING...WILL TREND TOWARD
A MIDDLE GROUND SOLUTION FOR NOW WHICH MEANS WINDY CONDITIONS WILL
PREVAIL THROUGH WEDNESDAY MORNING BUT WILL NOT QUITE REACH HIGH
WIND LEVELS. WILL KEEP MAINLY SLIGHT CHANCE POPS TUESDAY NIGHT
INTO WEDNESDAY MORNING FOR MUCH OF THE CWA EXCEPT IN THE
MOUNTAINS WHERE CHANCE POPS ARE REASONABLE. MOSTLY DRY CONDITIONS
AND LESS WIND WILL PREVAIL FOR THURSDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1114 AM MST FRI JAN 30 2015

CURRENTLY GETTING MVFR CATEGORY OBSERVED AT RAWLINS WY WHERE LIGHT
SNOW SHOWERS ARE PRODUCING VISIBILITIES DOWN TO 2SM...BUT THAT SHOULD
NOT BE A PREVAILING CONDITION THROUGH THE AFTERNOON WITH MVFR
CEILINGS BKN 2000FT AGL EXPECTED. OTHERWISE REST OF FORECAST AREA
EXPECTED TO SEE VFR CONDITIONS THROUGH THE EVENING WITH LOWERING
CEILINGS TO MVFR ACROSS THE ALLIANCE AND SIDNEY NE AREAS LATER
TONIGHT WITH LIGHT SOUTHERLY FLOW. MAY GET SOME PATCHY FOG IN
SPOTS TONIGHT (PARTICULARLY WHERE ANY LIGHT UPSLOW DEVELOPS). WILL
ALSO SEE A CHANCE OF LIGHT SNOW WITH MVFR CATEGORY CONDITIONS
POSSIBLE RAWLINS AND LARAMIE CLOSER TO WHERE ORAGRAPHICALLY
INDUCED SNOW SHOWERS IN THE MOUNTAINS ARE EXPECTED...BUT OTHERWISE
NO MAJOR CONCERNS THROUGH TOMORROW MORNING AND WE DONT EXPECT TO
SEE PREVAILING REDUCED VISIBILITIES DUE TO SNOW FOR THOSE
LOCATIONS THROUGH MORNING. THE HIGHER SNOW CHANCES THROUGH MORNING
ARE EXPECTED TO BE TO OUR SOUTH IN THE COLORADO MOUNTAINS.

&&

.FIRE WEATHER...
ISSUED AT 229 AM MST FRI JAN 30 2015

MINIMAL CONCERNS. A STRONG ARCTIC COLD FRONT WILL SWEEP QUICKLY
NORTH TO SOUTH ACROSS THE DISTRICT ON SATURDAY...USHERING IN
COLDER TEMPERATURES FOR SUNDAY. WARMING TEMPERATURES FOR MONDAY
AND TUESDAY BEFORE ANOTHER COLD FRONT BRINGS COOLER TEMPERATURES
FOR WEDNESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RUBIN
LONG TERM...RJM
AVIATION...JG
FIRE WEATHER...RUBIN



000
FXUS65 KRIW 301740
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1040 AM MST FRI JAN 30 2015

.UPDATE...ADDED 18Z AVIATION DISCUSSION BELOW


SHORT TERM...TODAY THROUGH SUNDAY NIGHT (ISSUED AT 323 AM MST)

EXCEPT FOR GEY...SO FAR VERY LITTLE FOG HAS BEEN DETECTED ACROSS
THE CWA IN RESPONSE TO THE HIGH CLOUDS MOVING IN FROM THE
SOUTHWEST. KEPT PATCHY FOG IN THE FORECAST HOWEVER AS IT IS ONLY
PATCHY AND NOCTURNAL INVERSIONS WILL PERSIST TO A LESSER EXTENT
OVER THE BASINS AND VALLEY THROUGH THIS MORNING. TOOK FOG OUT OF
GEY FOR THIS AFTERNOON. THE INCREASING HIGH CLOUDS ARE ASSOCIATED
WITH THE SOUTHERN STREAM CIRCULATION ALONG THE SOUTHERN CA/BAJA CA
COAST WHICH IS ANTICIPATED TO CONTINUE TO CLOSE OFF SOUTHWEST AND
SOUTH OF VEGAS TODAY AND TONIGHT. WITH THE MAIN ENERGY REMAINING
WELL TO OUR SOUTH...THE NORTHEAST EXTENT OF THIS CIRRUS SHIELD
WILL REMAIN ACROSS SOUTHERN WY TODAY WITH THE NORTHERN EXTENSION
CONTINUING TO DISSIPATE AS FAST AS IT MOVES NORTH. ANY MIXED
PRECIP THAT FALLS FROM THIS FEATURE WILL REMAIN ALONG AND SOUTH OF
INTERSTATE 80 TODAY AND TONIGHT. THIS WEATHER SYSTEM WILL PULL
AWAY INTO OLD MEXICO SATURDAY AND TAKE ITS CLOUDS AND PRECIP WITH
IT WELL TO OUR SOUTH. IN THE MEANTIME...A NORTHERN STREAM BRITISH
COLUMBIA CLIPPER WILL TRACK SOUTHEAST ACROSS MT/NE WY/NORTHERN AND
CENTRAL PLAINS SATURDAY NIGHT. THIS WX SYSTEM WILL BRING LIGHT
SNOW TO AREAS EAST OF THE DIVIDE...MAINLY IN THE MTNS AND IN
JOHNSON/NATRONA COUNTIES. THERE IS A CHANCE THAT A BAND OF LIGHT
PRECIP MAY LEAK THROUGH THE OWL CREEK/BRIDGER MTNS FROM THE BIG
HORN BASIN AND INTO THE WIND RIVER BASIN AS A SOUTHBOUND BAND OF
PRECIP ASSOCIATED WITH THE COLD FRONT MOVES SOUTH...ONLY AFFECTING
AREAS EAST OF THE DIVIDE THROUGH SUNDAY MORNING. H7 TEMPS WILL
BOTTOM OUT AT -16C IN NE JOHNSON COUNTY ON SUNDAY. H7 TEMPS WILL
REMAIN UNCHANGED WEST OF THE DIVIDE. THE FOLD OVER RIDGE NORTH OF
THE MEXICAN LOW WILL FLATTEN AND BACK THE FLOW MORE DIRECTLY OFF
THE PACIFIC THUS INCREASING THE LIKELIHOOD OF SNOW IN THE FAR WEST
BY SUNDAY NIGHT. AS FOR TEMPS...EXPECT SEASONABLY MILD TEMPS TODAY
AND SATURDAY. JOHNSON COUNTY SHOULD SEE THE BIGGEST COOL DOWN
SUNDAY WITH SUB 30 TEMPS. TEMPS QUICKLY WARM BACK UP MONDAY WITH
THE ZONAL FLOW.

LONG TERM...MONDAY THROUGH FRIDAY

A RELATIVELY MOIST WEST OR NORTHWEST FLOW WITH EMBEDDED SHORTWAVES
MONDAY THROUGH WEDNESDAY WILL RESULT IN PERIODS OF SNOWFALL OVER THE
WEST/NORTHWEST. TIMING AND SNOW AMOUNTS CONTINUE FLUCTUATE QUITE A
BIT...BUT THERE IS A GOOD CHANCE THAT THE FAR WESTERN MOUNTAINS AND
VALLEYS WILL SEE ONE OR TWO PERIODS WITH LIGHT TO MODERATE AMOUNTS
OF SNOWFALL IN THE MONDAY THROUGH WEDNESDAY TIME FRAME. RIGHT
NOW...MODELS ARE GENERALLY SHOWING THE HEAVIEST SNOWFALL OCCURRING
MONDAY NIGHT AND THEN AGAIN TUESDAY NIGHT.

00Z MODELS HAVE TRENDED WITH MORE OF A WESTERLY FLOW ALOFT. THIS
KEEPS THE BULK OF AN ARCTIC AIR MASS MAINLY NORTH AND EAST OF THE
FORECAST AREA THROUGH TUESDAY...BEFORE BRIEFLY PUSHING INTO THE AREA
TUESDAY NIGHT/WEDNESDAY. WITHOUT THIS ARCTIC FRONT TO FOCUS
PRECIPITATION...AREAS EAST OF THE DIVIDE SHOULD REMAIN MAINLY DRY
DUE TO DOWNSLOPING CONDITIONS MONDAY AND TUESDAY. THE ECMWF
CONTINUES TO BE THE MOST BULLISH IN PRECIPITATION EAST OF THE DIVIDE
WEDNESDAY. ALSO...WINDY CONDITIONS ARE EXPECTED IN THE ROCK SPRINGS
TO CASPER WIND CORRIDOR MONDAY AND TUESDAY...AND AT TIMES IN THE
CODY FOOTHILLS AND DUBOIS AREA.

GLOBAL MODELS SHOW AN UPPER RIDGE BUILDING INTO THE AREA THURSDAY
AND FRIDAY WITH MAINLY DRY AND MILD EARLY FEBRUARY TEMPERATURES. IF
THE ARCTIC AIR MASS CAN SETTLE INTO THE BASINS EAST OF THE DIVIDE
TUESDAY NIGHT/WEDNESDAY...TEMPERATURES WILL STRUGGLE TO WARM UP IN
THOSE TRAPPED BASIN...DESPITE WARMING TEMPERATURES ALOFT.

AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES

VFR CONDITIONS WILL PREVAIL THE REST OF THIS AFTERNOON...WITH FOG
LINGERING IN THE BIGHORN BASIN NEAR KGEY. N-NE SFC WINDS WILL
PREVAIL ACROSS THE AREA...WITH SOME LOWER CIGS EXPECTED TO FORM
ALONG THE EAST SLOPES OF THE DIVIDE AND OTHER UPSLOPE FAVORED
AREAS INCLUDING VCNTY KCPR. MOST OF THESE CIGS ARE EXPECTED TO
REMAIN VFR OBSCURING HIGHER MTNS. CLEARING IS EXPECTED AFTER 06Z
SATURDAY WITH PATCHY FOG REFORMING MAINLY IN THE LOWER CENTRAL
BASINS...OR VCNTY KGEY-KWRL.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES

AN UPPER LEVEL LOW PRESSURE SYSTEM OVER THE FOUR CORNERS...WILL
CONTINUE TO PUSH UP MOISTURE INTO SOUTHERN WYOMING THROUGH THE
PERIOD...WITH CIGS EXPECTED TO GRADUALLY LOWER VCNTY AND SOUTH OF
INTERSTATE 80...WITH SOME ISOLD TO SCT -SHSN MOVING IN EARLY THIS
EVENING ALONG WITH LOCAL MVFR/IFR CONDITIONS. MVFR/IFR CONDITIONS ARE
EXPECTED TO BECOME MORE PREVALENT IN THIS AREA AFTER 00Z SATURDAY.

NORTH OF INTERSTATE 80...VFR CONDITIONS WILL PREVAIL THROUGH THE
PERIOD.

FIRE WEATHER...

FIRE DANGER IS LOW FOR ALL AREAS...AND WILL REMAIN SO THROUGH NEXT
WEEK. MEASURABLE PRECIPITATION WILL NOT FALL ACROSS THE FORECAST
AREA UNTIL LATE SATURDAY INTO SUNDAY MORNING EAST OF THE DIVIDE.
FROM SUNDAY NIGHT THROUGH THE NEXT WORK WEEK...A SERIES OF
DISTURBANCES WILL RIDE THROUGH THE REGION...AFFECTING MAINLY THE
WESTERN AND NORTHERN DISPATCH ZONES. SMOKE DISPERSION WILL BE POOR
ACROSS MOST OF THE REGION TODAY. SATURDAY WILL SEE IMPROVEMENT IN
BOTH MIXING ABILITY AND DISPERSION...ESPECIALLY EAST OF THE DIVIDE
AND ACROSS THE SOUTHERN ZONES.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...LIPSON
LONG TERM...WM
AVIATION...AEM
FIRE WEATHER...LIPSON







000
FXUS63 KUNR 301659
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
959 AM MST FRI JAN 30 2015

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 236 AM MST FRI JAN 30 2015

WATER VAPOR SHOWS SHORT WAVE CROSSING THE NRN ROCKIES AND FLATTENING
THE UPPER RIDGE IN PLACE. AT THE SFC...ASSOCIATED TROF IS ADVANCING
INTO ERN MT/ERN WY.

TODAY...SHORT WAVE WILL CROSS THE NRN PLAINS AND PUSH THE SFC
BOUNDARY THROUGH THE DAKOTAS. THIS WILL ALLOW THERMAL RIDGE TO
NOSE INTO THE CWFA AND HELP PUSH TEMPS INTO THE 50S ON THE SD
PLAINS...A LITTLE COOLER FURTHER WEST. VERY LITTLE MOISTURE WITH
THIS SYSTEM SO DRY CONDITIONS EXPECTED.

SATURDAY...A STRONGER DISTURBANCE EMBEDDED IN THE NW FLOW ALOFT
WILL SHIFT THROUGH THE NRN ROCKIES INTO THE NRN PLAINS. TEMP FCST
WILL BE TRICKY AS ARCTIC AIR ATTEMPTS TO BACK INTO THE SD PLAINS
WHILE INVERTED SFC TROF OVER NERN WY KEEPS TEMPS WARMER IN THE
WEST. AS 140KT JET STREAK ON BACK SIDE OF TROF ENTERS THE WRN
ZONES LATE ON SATURDAY/SATURDAY NIGHT...ARCTIC WILL PLUNGE SWD
THROUGH THE ENTIRE CWFA. LARGE SCALE ASCENT ASSOCIATED WITH JET
STREAK AND LO LVL CAA WITH RESULT IN WDSPRD LIGHT SNOW ACROSS WRN
SD...WITH LESS OF A CHANCE IN NERN WY. ACCUMS SHOULD BE LIGHT IN
MOST AREAS...GENERALLY 2 INCHES OR LESS...GIVEN LACK OF MOISTURE.
TEMPS SATURDAY NIGHT SHOULD SETTLE IN THE SINGLE DIGITS ON THE SD
PLAINS AND SLIGHTLY WARMER IN THE WRN ZONES.

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 236 AM MST FRI JAN 30 2015

AN UNSETTLED AND COLDER PATTERN WILL PERSIST THROUGH AT LEAST
THE FIRST HALF OF NEXT WEEK. SHORTWAVE ENERGY WILL CROSS THE
NORTHERN PLAINS IN NORTHWEST FLOW...BRINGING LIGHT SNOW TO PARTS
OF THE AREA FROM TIME TO TIME. BEST CHANCES FOR LIGHT SNOW WILL BE
MONDAY NIGHT INTO TUESDAY MORNING ACROSS NORTHERN PORTIONS OF THE
FORECAST AREA. AN UPPER RIDGE IS PROGGED TO BUILD ACROSS THE
ROCKIES LATE NEXT WEEK...WITH DRY WEATHER EXPECTED.

THE TEMPERATURE FORECAST FOR THE FIRST HALF OF NEXT WEEK REMAINS
TRICKY AS SURFACE FRONTAL BOUNDARY MEANDERS ACROSS THE CWA AT TIMES.
A BRIEF WARMUP IS STILL EXPECTED ON MONDAY AHEAD OF THE SHORTWAVE
MONDAY NIGHT. COOLER AIR WILL AGAIN DIVE SOUTHWARD TUESDAY INTO
WEDNESDAY...ALTHOUGH MODELS DISAGREE ON EXACTLY HOW FAR WEST THE
COLDEST AIR WILL REACH. THE GFS AND ECMWF BOTH HAVE WARMER AIR
MOVING BACK INTO THE REGION TOWARDS THE END OF NEXT WEEK.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SATURDAY
ISSUED AT 956 AM MST FRI JAN 30 2015

VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY MORNING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JOHNSON
LONG TERM...15
AVIATION...POJORLIE







000
FXUS63 KUNR 301659
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
959 AM MST FRI JAN 30 2015

.SHORT TERM...TODAY THROUGH SATURDAY NIGHT
ISSUED AT 236 AM MST FRI JAN 30 2015

WATER VAPOR SHOWS SHORT WAVE CROSSING THE NRN ROCKIES AND FLATTENING
THE UPPER RIDGE IN PLACE. AT THE SFC...ASSOCIATED TROF IS ADVANCING
INTO ERN MT/ERN WY.

TODAY...SHORT WAVE WILL CROSS THE NRN PLAINS AND PUSH THE SFC
BOUNDARY THROUGH THE DAKOTAS. THIS WILL ALLOW THERMAL RIDGE TO
NOSE INTO THE CWFA AND HELP PUSH TEMPS INTO THE 50S ON THE SD
PLAINS...A LITTLE COOLER FURTHER WEST. VERY LITTLE MOISTURE WITH
THIS SYSTEM SO DRY CONDITIONS EXPECTED.

SATURDAY...A STRONGER DISTURBANCE EMBEDDED IN THE NW FLOW ALOFT
WILL SHIFT THROUGH THE NRN ROCKIES INTO THE NRN PLAINS. TEMP FCST
WILL BE TRICKY AS ARCTIC AIR ATTEMPTS TO BACK INTO THE SD PLAINS
WHILE INVERTED SFC TROF OVER NERN WY KEEPS TEMPS WARMER IN THE
WEST. AS 140KT JET STREAK ON BACK SIDE OF TROF ENTERS THE WRN
ZONES LATE ON SATURDAY/SATURDAY NIGHT...ARCTIC WILL PLUNGE SWD
THROUGH THE ENTIRE CWFA. LARGE SCALE ASCENT ASSOCIATED WITH JET
STREAK AND LO LVL CAA WITH RESULT IN WDSPRD LIGHT SNOW ACROSS WRN
SD...WITH LESS OF A CHANCE IN NERN WY. ACCUMS SHOULD BE LIGHT IN
MOST AREAS...GENERALLY 2 INCHES OR LESS...GIVEN LACK OF MOISTURE.
TEMPS SATURDAY NIGHT SHOULD SETTLE IN THE SINGLE DIGITS ON THE SD
PLAINS AND SLIGHTLY WARMER IN THE WRN ZONES.

.LONG TERM...SUNDAY THROUGH THURSDAY
ISSUED AT 236 AM MST FRI JAN 30 2015

AN UNSETTLED AND COLDER PATTERN WILL PERSIST THROUGH AT LEAST
THE FIRST HALF OF NEXT WEEK. SHORTWAVE ENERGY WILL CROSS THE
NORTHERN PLAINS IN NORTHWEST FLOW...BRINGING LIGHT SNOW TO PARTS
OF THE AREA FROM TIME TO TIME. BEST CHANCES FOR LIGHT SNOW WILL BE
MONDAY NIGHT INTO TUESDAY MORNING ACROSS NORTHERN PORTIONS OF THE
FORECAST AREA. AN UPPER RIDGE IS PROGGED TO BUILD ACROSS THE
ROCKIES LATE NEXT WEEK...WITH DRY WEATHER EXPECTED.

THE TEMPERATURE FORECAST FOR THE FIRST HALF OF NEXT WEEK REMAINS
TRICKY AS SURFACE FRONTAL BOUNDARY MEANDERS ACROSS THE CWA AT TIMES.
A BRIEF WARMUP IS STILL EXPECTED ON MONDAY AHEAD OF THE SHORTWAVE
MONDAY NIGHT. COOLER AIR WILL AGAIN DIVE SOUTHWARD TUESDAY INTO
WEDNESDAY...ALTHOUGH MODELS DISAGREE ON EXACTLY HOW FAR WEST THE
COLDEST AIR WILL REACH. THE GFS AND ECMWF BOTH HAVE WARMER AIR
MOVING BACK INTO THE REGION TOWARDS THE END OF NEXT WEEK.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z SATURDAY
ISSUED AT 956 AM MST FRI JAN 30 2015

VFR CONDITIONS ARE EXPECTED THROUGH SATURDAY MORNING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
WY...NONE.
&&

$$

SHORT TERM...JOHNSON
LONG TERM...15
AVIATION...POJORLIE






000
FXUS65 KCYS 301201
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
501 AM MST FRI JAN 30 2015

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 229 AM MST FRI JAN 30 2015

TODAY...DESPITE BROKEN TO OVERCAST SKIES OVER CARBON COUNTY...WE
MAY SEE SOME AREAS OF FOG THERE WITH TEMPERATURE AND DEWPOINT
SPREADS AROUND 3 DEGREES. WILL SEE INCREASING MIDDLE AND HIGH
CLOUDS AHEAD OF THE SHORTWAVE TROUGH ALOFT APPROACHING FROM
SOUTHERN ARIZONA...WITH A FEW SNOW SHOWERS OVER OUR SNOWY AND
SIERRA MADRE RANGES...DRY ELSEWHERE.

TONIGHT...AREAS OF FOG WILL INCREASE IN COVERAGE AS THE LOW LEVELS
SATURATE...THOUGH THE FOG COVERAGE WILL BE LIMITED SOMEWHAT BY
THE AMOUNT OF MIDDLE AND HIGH LEVEL CLOUDS. WITH SOME WEAK
SHORTWAVE TROUGH ALOFT ENERGY...UPSLOPE AND SATURATED LOW
LEVELS...EXPECT A CHANCE OF SNOW SOUTH OF A RAWLINS TO CHEYENNE
LINE.

SATURDAY...NEXT FAST MOVING SHORTWAVE TROUGH ALOFT...AN ALBERTA
TYPE CLIPPER...WILL MOVE TO NORTHEAST WYOMING SENDING THE NEXT
ARCTIC COLD FRONT SOUTH ACROSS OUR NORTHERN COUNTIES. ENOUGH LOW
AND MID LEVEL MOISTURE...NORTHERLY UPSLOPE AND WEAK UPWARD
VERTICAL MOTION TO PRODUCE A CHANCE OF LIGHT SNOW SOUTH OF A
RAWLINS TO SCOTTSBLUFF LINE.

SATURDAY NIGHT...STRONG COLD AIR ADVECTION AND CYCLONIC FLOW ALOFT
WILL WRING OUT A CHANCE OF LIGHT SNOW BUT WITH MINIMAL ACCUMULATIONS
DUE TO LACK OF LOW AND MID LEVEL MOISTURE.

SUNDAY...BREEZY AND COLD DAY WITH FAST NORTH NORTHWEST FLOW ALOFT
AND DECENT COLD AIR ADVECTION CONTINUING. HIGH TEMPERATURES WILL
STRUGGLE TO REACH FREEZING AT MOST LOCATIONS DESPITE SOME
SUNSHINE.

.LONG TERM...(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 229 AM MST FRI JAN 30 2015

AN UPPER LEVEL RIDGE WILL BUILD OVER THE ROCKIES SUNDAY NIGHT INTO
MONDAY WITH STRONG WAA OCCURRING OVER THE CWA THROUGH THIS TIME.
LOOKING AT TEMPS SPIKING INTO THE 40S AND 50S FOR MONDAY. SHORTWAVE
ENERGY ON THE NOSE OF A 100 KT JET WILL MOVE QUICKLY ATOP THE
RIDGE AND OVER THE ROCKIES AS WELL AND THE LEESIDE PRESSURE TROUGH
WILL RAPIDLY DEEPEN IN ADVANCE OF THIS WAVE. MODELS SHOW WINDS IN
THE 800-700 MB LAYER OVER SOUTHEAST WYOMING INCREASING TO 50+ KTS
LATE SUNDAY NIGHT AS THE LLVL PRESSURE GRADIENT STRENGTHENS. WITH
WAA IN PLACE...LIKELY TO SEE STRONG WINDS BECOME TRAPPED NEAR THE
SURFACE IN THE WIND PRONE AREAS OF SOUTHEAST WYOMING. UPSLOPE FLOW
ALONG THE WESTERN SLOPES WILL STRENGTHEN AS THESE WINDS DEVELOP
AND WILL COMBINE WITH INCREASED PACIFIC MOISTURE TO BRING A GOOD
CHANCE FOR OROGRAPHIC SNOW DURING THIS TIME AS WELL. THE LLVL
PRESSURE GRADIENT WILL RELAX SLIGHTLY ON MONDAY EVENING AS THE
INITIAL WAVE SHIFTS EAST...BUT ANOTHER AND SOMEWHAT STRONGER VORT
MAX WILL MOVE INTO THE NORTHERN ROCKIES MONDAY NIGHT AND WILL
REINTENSIFY THE GRADIENT. STILL THINKING THE WIND PRONE AREAS WILL
SEE A SECOND ROUND OF HIGH WINDS WHILE OROGRAPHIC SNOW INTENSIFIES
OVER THE MOUNTAINS MONDAY NIGHT THROUGH TUESDAY MORNING. HIGH
WINDS COULD EXPAND FURTHER EAST ONTO THE PLAINS LATE TUESDAY
MORNING WITH NEARLY 60 KTS PROGGED AT 750 MB AND ONLY PATCHY
CIRRUS OVERHEAD TO POTENTIALLY INHIBIT MIXING. CANT RULE OUT A FEW
SHOWERS MAINLY OVER THE NORTHERN ZONES FROM CONVERSE TO BOX BUTTE
COUNTIES TUESDAY MORNING AS THE VORT MOVES ACROSS THE NORTHERN
ROCKIES AND AN ASSOCIATED COLD FRONT STALLS OVER THIS AREA.

BEYOND TUESDAY...CONFIDENCE IS LOW WHETHER HIGH WINDS WILL BE
REALIZED IN THE WIND PRONE AREAS ONCE AGAIN WEDNESDAY
MORNING...OR IF THE COLD FRONT WILL MOVE SOUTH THRU THE PLAINS
EARLY ENOUGH TO SHUT OFF THE HIGH WINDS AND BRING RAIN/SNOW TO
THE CWA INSTEAD. THE 00Z GFS...EC AND GEM ALL SHOW VARIED
SOLUTIONS WITH THE SOUTHWARD SURGE OF THE FRONT...WITH THE GEM
NEARLY 12HRS FASTER THAN THE GFS...AND THE EC 6HRS SLOWER THAN THE
GFS. WITH THIS LEVEL OF VARIABILITY ON TIMING...WILL TREND TOWARD
A MIDDLE GROUND SOLUTION FOR NOW WHICH MEANS WINDY CONDITIONS WILL
PREVAIL THROUGH WEDNESDAY MORNING BUT WILL NOT QUITE REACH HIGH
WIND LEVELS. WILL KEEP MAINLY SLIGHT CHANCE POPS TUESDAY NIGHT
INTO WEDNESDAY MORNING FOR MUCH OF THE CWA EXCEPT IN THE
MOUNTAINS WHERE CHANCE POPS ARE REASONABLE. MOSTLY DRY CONDITIONS
AND LESS WIND WILL PREVAIL FOR THURSDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 500 AM MST FRI JAN 30 2015

MVFR/IFR STILL LOOK TO DEVELOP THIS MORNING AT KRWL...ALTHO
BACKED OFF THE TIMING OF STRATUS UNTIL LATER THIS MORNING BASED ON
LATEST SREF GUIDANCE. VFR CONDITIONS WILL PERSIST ELSEWHERE
THROUGH MOST OF TONIGHT...WITH LIGHT WINDS SHIFTING TO THE
NORTHEAST THIS AFTERNOON AND REMAINING LIGHT. MVFR CIGS LOOK TO
DEVELOP AT KLAR AND KCYS AFTER 08Z TONIGHT IN THIS NORTHEAST
UPSLOPE PATTERN WITH CIGS LEANING MORE TOWARD IFR AT KRWL.

&&

.FIRE WEATHER...
ISSUED AT 229 AM MST FRI JAN 30 2015

MINIMAL CONCERNS. A STRONG ARCTIC COLD FRONT WILL SWEEP QUICKLY
NORTH TO SOUTH ACROSS THE DISTRICT ON SATURDAY...USHERING IN
COLDER TEMPERATURES FOR SUNDAY. WARMING TEMPERATURES FOR MONDAY
AND TUESDAY BEFORE ANOTHER COLD FRONT BRINGS COOLER TEMPERATURES
FOR WEDNESDAY.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

SHORT TERM...RUBIN
LONG TERM...RJM
AVIATION...RJM
FIRE WEATHER...RUBIN




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