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000
FXUS65 KCYS 021859
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1159 AM MST MON MAR 2 2015

.UPDATE...
ISSUED AT 1151 AM MST MON MAR 2 2015

ADJUSTED CHANCES FOR PRECIPITATION AND CLOUD COVER OVER SOUTHEAST
PORTIONS OF THE FORECAST AREA FOR THIS AFTERNOON. THIS CHANGE
MAINLY AFFECT AREAS SOUTH AND EAST OF THE LINE FROM CHEYENNE TO
ALLIANCE. A DRY PUNCH OF AIR WILL PRODUCE MINIMAL CLOUD COVER AND
NO CHANCES FOR PRECIPITATION THROUGH THIS AFTERNOON.

SNOW CONTINUES TO FALL AT A RELATIVELY HIGH CLIP ACROSS MOST OF
CARBON COUNTY BUT FORTUNATELY WITH TEMPERATURES NEAR FREEZING AND
SOLAR HEATING...MOST ROAD SURFACES ARE WET AS OPPOSED TO SNOW
COVERED. ROADS WILL BECOME ICY THIS EVENING ONCE THE SUN SETS AND
TEMPERATURES BEGIN TO FALL...ESPECIALLY WHEN THE COLD FRONT MOVES
ACROSS THE AREA.

UPDATE ISSUED AT 929 AM MST MON MAR 2 2015

STARTED THE WINTER STORM WARNING FOR ALL OF CARBON COUNTY
EFFECTIVE IMMEDIATELY. SNOW IS ALREADY ACCUMULATING ON THE ROAD
SURFACES ACROSS MUCH OF THE COUNTY WITH 1 TO 2 INCHES OF SNOW ALREADY
ON THE GROUND IN RAWLINS. LATEST GFS SHOWING HIGH SNOW FALL RATES
AND BASED ON MOSAIC RADAR OVER WESTERN COLORADO...THERE IS NOT
MUCH DOUBT SNOW WILL CONTINUE TO INTENSIFY THIS MORNING WITH SNOW
HEAVY AT TIMES THROUGH THIS AFTERNOON. THE REST OF THE WINTER
STORM PRODUCTS LOOK FINE. SOME LIGHT SNOW ACCUMULATIONS WILL
OCCUR AROUND LARAMIE BUT NOT MAIN PRECIPITATION AREA WILL SHIFT
SLIGHTLY WEST THIS AFTERNOON BEFORE SPREADING EAST TONIGHT WITH
THE MAIN UPPER LEVEL FEATURE.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 430 AM MST MON MAR 2 2015

A BUSY FORECAST PERIOD CONTINUES WITH A MAJOR WINTER STORM STILL
ON TRACK FOR MUCH OF THE CWA. MAIN CHALLENGES REVOLVE AROUND THE
TIMING/PLACEMENT OF HEAVIEST SNOWFALL AND WHAT IMPACTS THIS WILL
HAVE TO TRAVEL. DANGEROUS WIND CHILLS WILL UNDOUBTEDLY BECOME AN
ISSUE BY TUE NIGHT AND WED...AND TEMPERATURES WILL HINGE ON CLOUD
COVER AND SNOW DEPTHS HEADING INTO MIDWEEK. MORNING WV SAT IMAGERY
SHOWS DEEP TROUGHING OVER THE WESTERN CONUS. A SEPARATE AND MORE
VIGOROUS PIECE OF ENERGY WAS LOCATED OVER SOUTHERN CAL WITH THE
MUCH ANTICIPATED KICKER SYSTEM DIVING SOUTH ALONG THE WESTERN US
COASTLINE. EXCELLENT MOISTURE FETCH WAS OBSERVED DOWNSTREAM OVER
THE FOUR CORNERS...AS WELL AS GOOD INSTABILITY WITH A FEW RECENT
LIGHTNING STRIKES OVER CA/NV BENEATH THE UPPER LOW. THAT SAID...
CONFIDENCE IS HIGH FOR A HEAVY SNOWFALL EVENT IN OUR CWA.

WE DECIDED TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE
REST OF CARBON COUNTY...KEEPING START/END TIMES THE SAME. WE HAVE
SEEN SOLID RUN-TO-RUN AND MODEL-TO-MODEL CONSISTENCY AMONG BOTH
AMERICAN AND EUROPEAN GUIDANCE OVER THE LAST DAY OR SO. CONSENSUS
IS FOR THE SOUTHERN WAVE TO LIFT NORTHEAST INTO WESTERN CO BY THIS
AFTN WITH AN IMPRESSIVE 160+ KT H25 JET NOSING INTO SOUTHEAST WY
BY 00Z TUE. THIS PLACES OUR WESTERN ZONES IN THE FAVORED LEFT EXIT
REGION FOR A FEW HOURS THIS AFTERNOON...SO A PERIOD OF HEAVY SNOW
BANDING IS LIKELY WITH A SURFACE WARM FRONTAL BOUNDARY ORIENTED
FROM SW TO NE ACROSS THE CWA. NAM AND GFS MUCAPES BETWEEN 100 AND
200 J/KG SUGGESTS SOME CONVECTIVE ELEMENTS...SO RATES COULD EXCEED
AN INCH PER HOUR AT TIMES. SNOWIES AND SIERRA MADRES ARE STILL IN
GOOD SHAPE FOR AROUND 2 FEET OF TOTAL ACCUMULATIONS.

THE MORE WIDESPREAD EVENT HOLDS OFF UNTIL LATER THIS EVENING AND
OVERNIGHT WITH THE COLD FROPA. GFS/NAM/ECMWF ARE ALL IN EXCELLENT
AGREEMENT WITH THE ARCTIC FRONT SURGING SOUTH BETWEEN 06Z AND 12Z
TUE. SIGNIFICANT LLVL COLD ADVECTION SHOULD OCCUR WITH GFS 700 MB
TEMPS OVER CYS FALLING FROM +1C AT 00Z TO -13C AT 12Z TUE. FRONTAL
PASSAGE WILL RESULT IN ENHANCED LLVL CONVERGENCE AND FRONTOGENESIS
ALONG THE LARAMIE RANGE...AND UPSLOPE FLOW MOST PRONOUNCED OVER
THE NORTHERN MOUNTAINS. LATEST RUNS HAVE BEEN HITTING THE NORTH
LARAMIE RANGE HARD WITH AN AVERAGE OF AROUND 0.7 INCH QPF...WHICH
IS NOT SURPRISING WITH STEEPENING LAPSE RATES ALOFT. BEST SUPPORT
WILL BE FAST MOVING...BUT RATES SHOULD BE HIGH ENOUGH TO GET CLOSE
TO A FOOT OF SNOW OVER NORTH FACING SLOPES. WINDS SHOULD COME INTO
PLAY AS WELL AS COLD ADVECTION YIELDS STRONG MIXING OVERNIGHT WITH
30 TO 40 KTS AVAILABLE TO MIX. WENT AHEAD AND ADDED THE NORTHERN
LARAMIE RANGE AND LOWER ELEVATIONS OF CONVERSE TO THE WARNING EVEN
THOUGH AMOUNTS COULD BE MARGINAL.

A BAND OF SNOW SHOULD EXTEND FARTHER EAST ONTO THE PLAINS TOWARD
THE WESTERN NEBRASKA PANHANDLE. MOST LIKELY AREA FOR THIS TO OCCUR
IS ACROSS THE NORTHERN ZONES WITH THE INITIAL FRONTAL SURGE. BIG
QUESTIONS FOR THE INTERSTATE 80 CORRIDOR AS H7-H3 RH PROGS SHOW A
SUBSTANTIAL DRY SLOT SNEAKING INTO OUR EXTREME SOUTHEAST CWA. WE
BELIEVE LIGHT ACCUMULATIONS AND INCREASING WINDS TONIGHT WILL BE
ENOUGH TO CAUSE SIGNIFICANT TRAVEL DIFFICULTY...ESPECIALLY ALONG
INTERSTATE 80. DECIDED ON A WINTER WEATHER ADVISORY FROM THE SOUTH
LARAMIE RANGE NORTHEAST INTO THE NORTHERN PANHANDLE. SNOW SHOULD
SLOWLY END ON TUE NIGHT AND WED AS THE SYSTEM DEPARTS...BUT A FEW
SHOWERS WILL PERSIST AS A SECONDARY SHORTWAVE SWINGS AROUND THE
BACK SIDE OF THE LARGER SCALE TROUGH. DESPITE PLENTY OF CLOUDS
PREVENTING MAJOR RADIATIONAL COOLING...H7 TEMPS AS COLD AS -20 C
AT 12Z WED SUGGESTS SUB ZERO READINGS. EXPECT THAT SOME SORT OF
WIND CHILL HEADLINES WILL BE NECESSARY ON THE HEELS OF ONGOING
WINTER WEATHER PRODUCTS. KEPT HIGHS BELOW GUIDANCE FOR BOTH TUE
AND WED WITH WIDESPREAD SNOW AND COLD ADVECTION ALOFT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 AM MST MON MAR 2 2015

00Z MODELS INDICATE NORTHWEST FLOW ALOFT BEHIND EXITING TROUGH
AND UPPER RIDGE EXPANDING EAST TOWARD THE GREAT BASIN. A WEAK
SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE CWA THURSDAY MORNING
WITH LITTLE OR NO ASSOCIATED MOISTURE. 700MB WINDS INCREASE TO
50 KT ALONG THE I-80 CORRIDOR BETWEEN ARLINGTON AND CHEYENNE
WEDNESDAY NIGHT/THURSDAY MORNING. OVER THE NORTH SNOWY RANGE
FOOTHILLS/CENTRAL LARAMIE RANGE. THE CENTER OF UPPER RIDGE MOVES
INTO CA/NV FRIDAY WITH LIGHTER NORTHWEST FLOW. THERE ARE MODEL
DIFFERENCES THIS WEEKEND AS THE ECMWF SHOWS A POTENT SHORTWAVE
TROUGH TRACKING SOUTHEAST FROM ID/WESTERN MT ACROSS WY/CO
SATURDAY...PRODUCING LIGHT PRECIPITATION. THE GFS DOES NOT SHOW
THIS FEATURE BUT AMPLIFIES THE NORTHWEST FLOW ALOFT AS SHORTWAVE
ENERGY MOVES ACROSS THE NORTHERN U.S. FOR NOW...LEFT POPS BELOW
15 PERCENT BUT THEY MAY BE INCREASED LATER IF THE GFS TRENDS
TOWARD THE ECMWF. A COLD FRONT WILL MOVE THROUGH THE REGION
SATURDAY. IT DOES NOT LOOK AS COLD BEHIND THE FRONT COMPARED TO
EARLIER MODEL RUNS. HIGHS THURSDAY WILL BE ABOUT 20 DEGREES WARMER
THAN WEDNESDAY AS DOWNSLOPE WEST-NORTHWEST WINDS DEVELOP LEE OF
LARAMIE RANGE. TEMPERATURES FINALLY WARM TO NEAR SEASONAL NORMALS
FRIDAY WITH HIGHS IN THE 30S AND 40S. IT WILL BE A TAD COOLER FOR
THE PLAINS SATURDAY. UPPER RIDGE BUILDS CLOSER WITH DOWNSLOPE
NORTHWEST FLOW KEEPING TEMPERATURES SEASONABLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1031 AM MST MON MAR 2 2015

LIFR CONDS WITH SNOW AND LOW CIGS LIKELY THROUGH THE PD AFFECTING
THE KRWL AREA WHILE ELSEWHERE SCTD MVFR CIGS EXPECTED THROUGH THIS
EVENING.  SFC COLD FRONT WILL MOVE SOUTH ACROSS THE AREA LATE THIS
EVENING AND OVERNIGHT WITH MAINLY IFR CONDITIONS BECOMING WIDESPREAD
LATER TONIGHT INTO TUESDAY MORNING.


&&

.FIRE WEATHER...
ISSUED AT 430 AM MST MON MAR 2 2015

NO FIRE WEATHER CONCERNS. SNOW IS EXPECTED TO DEVELOP TODAY AND
BECOME WIDESPREAD TONIGHT AND TUESDAY. SIGNIFICANT ACCUMULATIONS
ARE POSSIBLE...ESPECIALLY IN THE MOUNTAINS AND LOWER ELEVATION
AREAS WEST OF THE LARAMIE RANGE. THE SNOW WILL GRADUALLY DIMINISH
BY TUESDAY NIGHT. AN ARCTIC COLD FRONT WILL BRING BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS FROM TUESDAY NIGHT THROUGH
WEDNESDAY. MODERATING TEMPERATURES ARE EXPECTED LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR WYZ102-106>108-115>117.

     WINTER STORM WARNING UNTIL 6 PM MST TUESDAY FOR WYZ104-105-
     109>114.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 PM MST
     TUESDAY FOR WYZ101-103.

NE...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR NEZ002-003-095-096.

&&

$$

UPDATE...SML
SHORT TERM...CLH
LONG TERM...MJ
AVIATION...RE
FIRE WEATHER...CLH



000
FXUS65 KCYS 021859
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1159 AM MST MON MAR 2 2015

.UPDATE...
ISSUED AT 1151 AM MST MON MAR 2 2015

ADJUSTED CHANCES FOR PRECIPITATION AND CLOUD COVER OVER SOUTHEAST
PORTIONS OF THE FORECAST AREA FOR THIS AFTERNOON. THIS CHANGE
MAINLY AFFECT AREAS SOUTH AND EAST OF THE LINE FROM CHEYENNE TO
ALLIANCE. A DRY PUNCH OF AIR WILL PRODUCE MINIMAL CLOUD COVER AND
NO CHANCES FOR PRECIPITATION THROUGH THIS AFTERNOON.

SNOW CONTINUES TO FALL AT A RELATIVELY HIGH CLIP ACROSS MOST OF
CARBON COUNTY BUT FORTUNATELY WITH TEMPERATURES NEAR FREEZING AND
SOLAR HEATING...MOST ROAD SURFACES ARE WET AS OPPOSED TO SNOW
COVERED. ROADS WILL BECOME ICY THIS EVENING ONCE THE SUN SETS AND
TEMPERATURES BEGIN TO FALL...ESPECIALLY WHEN THE COLD FRONT MOVES
ACROSS THE AREA.

UPDATE ISSUED AT 929 AM MST MON MAR 2 2015

STARTED THE WINTER STORM WARNING FOR ALL OF CARBON COUNTY
EFFECTIVE IMMEDIATELY. SNOW IS ALREADY ACCUMULATING ON THE ROAD
SURFACES ACROSS MUCH OF THE COUNTY WITH 1 TO 2 INCHES OF SNOW ALREADY
ON THE GROUND IN RAWLINS. LATEST GFS SHOWING HIGH SNOW FALL RATES
AND BASED ON MOSAIC RADAR OVER WESTERN COLORADO...THERE IS NOT
MUCH DOUBT SNOW WILL CONTINUE TO INTENSIFY THIS MORNING WITH SNOW
HEAVY AT TIMES THROUGH THIS AFTERNOON. THE REST OF THE WINTER
STORM PRODUCTS LOOK FINE. SOME LIGHT SNOW ACCUMULATIONS WILL
OCCUR AROUND LARAMIE BUT NOT MAIN PRECIPITATION AREA WILL SHIFT
SLIGHTLY WEST THIS AFTERNOON BEFORE SPREADING EAST TONIGHT WITH
THE MAIN UPPER LEVEL FEATURE.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 430 AM MST MON MAR 2 2015

A BUSY FORECAST PERIOD CONTINUES WITH A MAJOR WINTER STORM STILL
ON TRACK FOR MUCH OF THE CWA. MAIN CHALLENGES REVOLVE AROUND THE
TIMING/PLACEMENT OF HEAVIEST SNOWFALL AND WHAT IMPACTS THIS WILL
HAVE TO TRAVEL. DANGEROUS WIND CHILLS WILL UNDOUBTEDLY BECOME AN
ISSUE BY TUE NIGHT AND WED...AND TEMPERATURES WILL HINGE ON CLOUD
COVER AND SNOW DEPTHS HEADING INTO MIDWEEK. MORNING WV SAT IMAGERY
SHOWS DEEP TROUGHING OVER THE WESTERN CONUS. A SEPARATE AND MORE
VIGOROUS PIECE OF ENERGY WAS LOCATED OVER SOUTHERN CAL WITH THE
MUCH ANTICIPATED KICKER SYSTEM DIVING SOUTH ALONG THE WESTERN US
COASTLINE. EXCELLENT MOISTURE FETCH WAS OBSERVED DOWNSTREAM OVER
THE FOUR CORNERS...AS WELL AS GOOD INSTABILITY WITH A FEW RECENT
LIGHTNING STRIKES OVER CA/NV BENEATH THE UPPER LOW. THAT SAID...
CONFIDENCE IS HIGH FOR A HEAVY SNOWFALL EVENT IN OUR CWA.

WE DECIDED TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE
REST OF CARBON COUNTY...KEEPING START/END TIMES THE SAME. WE HAVE
SEEN SOLID RUN-TO-RUN AND MODEL-TO-MODEL CONSISTENCY AMONG BOTH
AMERICAN AND EUROPEAN GUIDANCE OVER THE LAST DAY OR SO. CONSENSUS
IS FOR THE SOUTHERN WAVE TO LIFT NORTHEAST INTO WESTERN CO BY THIS
AFTN WITH AN IMPRESSIVE 160+ KT H25 JET NOSING INTO SOUTHEAST WY
BY 00Z TUE. THIS PLACES OUR WESTERN ZONES IN THE FAVORED LEFT EXIT
REGION FOR A FEW HOURS THIS AFTERNOON...SO A PERIOD OF HEAVY SNOW
BANDING IS LIKELY WITH A SURFACE WARM FRONTAL BOUNDARY ORIENTED
FROM SW TO NE ACROSS THE CWA. NAM AND GFS MUCAPES BETWEEN 100 AND
200 J/KG SUGGESTS SOME CONVECTIVE ELEMENTS...SO RATES COULD EXCEED
AN INCH PER HOUR AT TIMES. SNOWIES AND SIERRA MADRES ARE STILL IN
GOOD SHAPE FOR AROUND 2 FEET OF TOTAL ACCUMULATIONS.

THE MORE WIDESPREAD EVENT HOLDS OFF UNTIL LATER THIS EVENING AND
OVERNIGHT WITH THE COLD FROPA. GFS/NAM/ECMWF ARE ALL IN EXCELLENT
AGREEMENT WITH THE ARCTIC FRONT SURGING SOUTH BETWEEN 06Z AND 12Z
TUE. SIGNIFICANT LLVL COLD ADVECTION SHOULD OCCUR WITH GFS 700 MB
TEMPS OVER CYS FALLING FROM +1C AT 00Z TO -13C AT 12Z TUE. FRONTAL
PASSAGE WILL RESULT IN ENHANCED LLVL CONVERGENCE AND FRONTOGENESIS
ALONG THE LARAMIE RANGE...AND UPSLOPE FLOW MOST PRONOUNCED OVER
THE NORTHERN MOUNTAINS. LATEST RUNS HAVE BEEN HITTING THE NORTH
LARAMIE RANGE HARD WITH AN AVERAGE OF AROUND 0.7 INCH QPF...WHICH
IS NOT SURPRISING WITH STEEPENING LAPSE RATES ALOFT. BEST SUPPORT
WILL BE FAST MOVING...BUT RATES SHOULD BE HIGH ENOUGH TO GET CLOSE
TO A FOOT OF SNOW OVER NORTH FACING SLOPES. WINDS SHOULD COME INTO
PLAY AS WELL AS COLD ADVECTION YIELDS STRONG MIXING OVERNIGHT WITH
30 TO 40 KTS AVAILABLE TO MIX. WENT AHEAD AND ADDED THE NORTHERN
LARAMIE RANGE AND LOWER ELEVATIONS OF CONVERSE TO THE WARNING EVEN
THOUGH AMOUNTS COULD BE MARGINAL.

A BAND OF SNOW SHOULD EXTEND FARTHER EAST ONTO THE PLAINS TOWARD
THE WESTERN NEBRASKA PANHANDLE. MOST LIKELY AREA FOR THIS TO OCCUR
IS ACROSS THE NORTHERN ZONES WITH THE INITIAL FRONTAL SURGE. BIG
QUESTIONS FOR THE INTERSTATE 80 CORRIDOR AS H7-H3 RH PROGS SHOW A
SUBSTANTIAL DRY SLOT SNEAKING INTO OUR EXTREME SOUTHEAST CWA. WE
BELIEVE LIGHT ACCUMULATIONS AND INCREASING WINDS TONIGHT WILL BE
ENOUGH TO CAUSE SIGNIFICANT TRAVEL DIFFICULTY...ESPECIALLY ALONG
INTERSTATE 80. DECIDED ON A WINTER WEATHER ADVISORY FROM THE SOUTH
LARAMIE RANGE NORTHEAST INTO THE NORTHERN PANHANDLE. SNOW SHOULD
SLOWLY END ON TUE NIGHT AND WED AS THE SYSTEM DEPARTS...BUT A FEW
SHOWERS WILL PERSIST AS A SECONDARY SHORTWAVE SWINGS AROUND THE
BACK SIDE OF THE LARGER SCALE TROUGH. DESPITE PLENTY OF CLOUDS
PREVENTING MAJOR RADIATIONAL COOLING...H7 TEMPS AS COLD AS -20 C
AT 12Z WED SUGGESTS SUB ZERO READINGS. EXPECT THAT SOME SORT OF
WIND CHILL HEADLINES WILL BE NECESSARY ON THE HEELS OF ONGOING
WINTER WEATHER PRODUCTS. KEPT HIGHS BELOW GUIDANCE FOR BOTH TUE
AND WED WITH WIDESPREAD SNOW AND COLD ADVECTION ALOFT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 AM MST MON MAR 2 2015

00Z MODELS INDICATE NORTHWEST FLOW ALOFT BEHIND EXITING TROUGH
AND UPPER RIDGE EXPANDING EAST TOWARD THE GREAT BASIN. A WEAK
SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE CWA THURSDAY MORNING
WITH LITTLE OR NO ASSOCIATED MOISTURE. 700MB WINDS INCREASE TO
50 KT ALONG THE I-80 CORRIDOR BETWEEN ARLINGTON AND CHEYENNE
WEDNESDAY NIGHT/THURSDAY MORNING. OVER THE NORTH SNOWY RANGE
FOOTHILLS/CENTRAL LARAMIE RANGE. THE CENTER OF UPPER RIDGE MOVES
INTO CA/NV FRIDAY WITH LIGHTER NORTHWEST FLOW. THERE ARE MODEL
DIFFERENCES THIS WEEKEND AS THE ECMWF SHOWS A POTENT SHORTWAVE
TROUGH TRACKING SOUTHEAST FROM ID/WESTERN MT ACROSS WY/CO
SATURDAY...PRODUCING LIGHT PRECIPITATION. THE GFS DOES NOT SHOW
THIS FEATURE BUT AMPLIFIES THE NORTHWEST FLOW ALOFT AS SHORTWAVE
ENERGY MOVES ACROSS THE NORTHERN U.S. FOR NOW...LEFT POPS BELOW
15 PERCENT BUT THEY MAY BE INCREASED LATER IF THE GFS TRENDS
TOWARD THE ECMWF. A COLD FRONT WILL MOVE THROUGH THE REGION
SATURDAY. IT DOES NOT LOOK AS COLD BEHIND THE FRONT COMPARED TO
EARLIER MODEL RUNS. HIGHS THURSDAY WILL BE ABOUT 20 DEGREES WARMER
THAN WEDNESDAY AS DOWNSLOPE WEST-NORTHWEST WINDS DEVELOP LEE OF
LARAMIE RANGE. TEMPERATURES FINALLY WARM TO NEAR SEASONAL NORMALS
FRIDAY WITH HIGHS IN THE 30S AND 40S. IT WILL BE A TAD COOLER FOR
THE PLAINS SATURDAY. UPPER RIDGE BUILDS CLOSER WITH DOWNSLOPE
NORTHWEST FLOW KEEPING TEMPERATURES SEASONABLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1031 AM MST MON MAR 2 2015

LIFR CONDS WITH SNOW AND LOW CIGS LIKELY THROUGH THE PD AFFECTING
THE KRWL AREA WHILE ELSEWHERE SCTD MVFR CIGS EXPECTED THROUGH THIS
EVENING.  SFC COLD FRONT WILL MOVE SOUTH ACROSS THE AREA LATE THIS
EVENING AND OVERNIGHT WITH MAINLY IFR CONDITIONS BECOMING WIDESPREAD
LATER TONIGHT INTO TUESDAY MORNING.


&&

.FIRE WEATHER...
ISSUED AT 430 AM MST MON MAR 2 2015

NO FIRE WEATHER CONCERNS. SNOW IS EXPECTED TO DEVELOP TODAY AND
BECOME WIDESPREAD TONIGHT AND TUESDAY. SIGNIFICANT ACCUMULATIONS
ARE POSSIBLE...ESPECIALLY IN THE MOUNTAINS AND LOWER ELEVATION
AREAS WEST OF THE LARAMIE RANGE. THE SNOW WILL GRADUALLY DIMINISH
BY TUESDAY NIGHT. AN ARCTIC COLD FRONT WILL BRING BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS FROM TUESDAY NIGHT THROUGH
WEDNESDAY. MODERATING TEMPERATURES ARE EXPECTED LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR WYZ102-106>108-115>117.

     WINTER STORM WARNING UNTIL 6 PM MST TUESDAY FOR WYZ104-105-
     109>114.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 PM MST
     TUESDAY FOR WYZ101-103.

NE...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR NEZ002-003-095-096.

&&

$$

UPDATE...SML
SHORT TERM...CLH
LONG TERM...MJ
AVIATION...RE
FIRE WEATHER...CLH



000
FXUS65 KCYS 021859
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1159 AM MST MON MAR 2 2015

.UPDATE...
ISSUED AT 1151 AM MST MON MAR 2 2015

ADJUSTED CHANCES FOR PRECIPITATION AND CLOUD COVER OVER SOUTHEAST
PORTIONS OF THE FORECAST AREA FOR THIS AFTERNOON. THIS CHANGE
MAINLY AFFECT AREAS SOUTH AND EAST OF THE LINE FROM CHEYENNE TO
ALLIANCE. A DRY PUNCH OF AIR WILL PRODUCE MINIMAL CLOUD COVER AND
NO CHANCES FOR PRECIPITATION THROUGH THIS AFTERNOON.

SNOW CONTINUES TO FALL AT A RELATIVELY HIGH CLIP ACROSS MOST OF
CARBON COUNTY BUT FORTUNATELY WITH TEMPERATURES NEAR FREEZING AND
SOLAR HEATING...MOST ROAD SURFACES ARE WET AS OPPOSED TO SNOW
COVERED. ROADS WILL BECOME ICY THIS EVENING ONCE THE SUN SETS AND
TEMPERATURES BEGIN TO FALL...ESPECIALLY WHEN THE COLD FRONT MOVES
ACROSS THE AREA.

UPDATE ISSUED AT 929 AM MST MON MAR 2 2015

STARTED THE WINTER STORM WARNING FOR ALL OF CARBON COUNTY
EFFECTIVE IMMEDIATELY. SNOW IS ALREADY ACCUMULATING ON THE ROAD
SURFACES ACROSS MUCH OF THE COUNTY WITH 1 TO 2 INCHES OF SNOW ALREADY
ON THE GROUND IN RAWLINS. LATEST GFS SHOWING HIGH SNOW FALL RATES
AND BASED ON MOSAIC RADAR OVER WESTERN COLORADO...THERE IS NOT
MUCH DOUBT SNOW WILL CONTINUE TO INTENSIFY THIS MORNING WITH SNOW
HEAVY AT TIMES THROUGH THIS AFTERNOON. THE REST OF THE WINTER
STORM PRODUCTS LOOK FINE. SOME LIGHT SNOW ACCUMULATIONS WILL
OCCUR AROUND LARAMIE BUT NOT MAIN PRECIPITATION AREA WILL SHIFT
SLIGHTLY WEST THIS AFTERNOON BEFORE SPREADING EAST TONIGHT WITH
THE MAIN UPPER LEVEL FEATURE.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 430 AM MST MON MAR 2 2015

A BUSY FORECAST PERIOD CONTINUES WITH A MAJOR WINTER STORM STILL
ON TRACK FOR MUCH OF THE CWA. MAIN CHALLENGES REVOLVE AROUND THE
TIMING/PLACEMENT OF HEAVIEST SNOWFALL AND WHAT IMPACTS THIS WILL
HAVE TO TRAVEL. DANGEROUS WIND CHILLS WILL UNDOUBTEDLY BECOME AN
ISSUE BY TUE NIGHT AND WED...AND TEMPERATURES WILL HINGE ON CLOUD
COVER AND SNOW DEPTHS HEADING INTO MIDWEEK. MORNING WV SAT IMAGERY
SHOWS DEEP TROUGHING OVER THE WESTERN CONUS. A SEPARATE AND MORE
VIGOROUS PIECE OF ENERGY WAS LOCATED OVER SOUTHERN CAL WITH THE
MUCH ANTICIPATED KICKER SYSTEM DIVING SOUTH ALONG THE WESTERN US
COASTLINE. EXCELLENT MOISTURE FETCH WAS OBSERVED DOWNSTREAM OVER
THE FOUR CORNERS...AS WELL AS GOOD INSTABILITY WITH A FEW RECENT
LIGHTNING STRIKES OVER CA/NV BENEATH THE UPPER LOW. THAT SAID...
CONFIDENCE IS HIGH FOR A HEAVY SNOWFALL EVENT IN OUR CWA.

WE DECIDED TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE
REST OF CARBON COUNTY...KEEPING START/END TIMES THE SAME. WE HAVE
SEEN SOLID RUN-TO-RUN AND MODEL-TO-MODEL CONSISTENCY AMONG BOTH
AMERICAN AND EUROPEAN GUIDANCE OVER THE LAST DAY OR SO. CONSENSUS
IS FOR THE SOUTHERN WAVE TO LIFT NORTHEAST INTO WESTERN CO BY THIS
AFTN WITH AN IMPRESSIVE 160+ KT H25 JET NOSING INTO SOUTHEAST WY
BY 00Z TUE. THIS PLACES OUR WESTERN ZONES IN THE FAVORED LEFT EXIT
REGION FOR A FEW HOURS THIS AFTERNOON...SO A PERIOD OF HEAVY SNOW
BANDING IS LIKELY WITH A SURFACE WARM FRONTAL BOUNDARY ORIENTED
FROM SW TO NE ACROSS THE CWA. NAM AND GFS MUCAPES BETWEEN 100 AND
200 J/KG SUGGESTS SOME CONVECTIVE ELEMENTS...SO RATES COULD EXCEED
AN INCH PER HOUR AT TIMES. SNOWIES AND SIERRA MADRES ARE STILL IN
GOOD SHAPE FOR AROUND 2 FEET OF TOTAL ACCUMULATIONS.

THE MORE WIDESPREAD EVENT HOLDS OFF UNTIL LATER THIS EVENING AND
OVERNIGHT WITH THE COLD FROPA. GFS/NAM/ECMWF ARE ALL IN EXCELLENT
AGREEMENT WITH THE ARCTIC FRONT SURGING SOUTH BETWEEN 06Z AND 12Z
TUE. SIGNIFICANT LLVL COLD ADVECTION SHOULD OCCUR WITH GFS 700 MB
TEMPS OVER CYS FALLING FROM +1C AT 00Z TO -13C AT 12Z TUE. FRONTAL
PASSAGE WILL RESULT IN ENHANCED LLVL CONVERGENCE AND FRONTOGENESIS
ALONG THE LARAMIE RANGE...AND UPSLOPE FLOW MOST PRONOUNCED OVER
THE NORTHERN MOUNTAINS. LATEST RUNS HAVE BEEN HITTING THE NORTH
LARAMIE RANGE HARD WITH AN AVERAGE OF AROUND 0.7 INCH QPF...WHICH
IS NOT SURPRISING WITH STEEPENING LAPSE RATES ALOFT. BEST SUPPORT
WILL BE FAST MOVING...BUT RATES SHOULD BE HIGH ENOUGH TO GET CLOSE
TO A FOOT OF SNOW OVER NORTH FACING SLOPES. WINDS SHOULD COME INTO
PLAY AS WELL AS COLD ADVECTION YIELDS STRONG MIXING OVERNIGHT WITH
30 TO 40 KTS AVAILABLE TO MIX. WENT AHEAD AND ADDED THE NORTHERN
LARAMIE RANGE AND LOWER ELEVATIONS OF CONVERSE TO THE WARNING EVEN
THOUGH AMOUNTS COULD BE MARGINAL.

A BAND OF SNOW SHOULD EXTEND FARTHER EAST ONTO THE PLAINS TOWARD
THE WESTERN NEBRASKA PANHANDLE. MOST LIKELY AREA FOR THIS TO OCCUR
IS ACROSS THE NORTHERN ZONES WITH THE INITIAL FRONTAL SURGE. BIG
QUESTIONS FOR THE INTERSTATE 80 CORRIDOR AS H7-H3 RH PROGS SHOW A
SUBSTANTIAL DRY SLOT SNEAKING INTO OUR EXTREME SOUTHEAST CWA. WE
BELIEVE LIGHT ACCUMULATIONS AND INCREASING WINDS TONIGHT WILL BE
ENOUGH TO CAUSE SIGNIFICANT TRAVEL DIFFICULTY...ESPECIALLY ALONG
INTERSTATE 80. DECIDED ON A WINTER WEATHER ADVISORY FROM THE SOUTH
LARAMIE RANGE NORTHEAST INTO THE NORTHERN PANHANDLE. SNOW SHOULD
SLOWLY END ON TUE NIGHT AND WED AS THE SYSTEM DEPARTS...BUT A FEW
SHOWERS WILL PERSIST AS A SECONDARY SHORTWAVE SWINGS AROUND THE
BACK SIDE OF THE LARGER SCALE TROUGH. DESPITE PLENTY OF CLOUDS
PREVENTING MAJOR RADIATIONAL COOLING...H7 TEMPS AS COLD AS -20 C
AT 12Z WED SUGGESTS SUB ZERO READINGS. EXPECT THAT SOME SORT OF
WIND CHILL HEADLINES WILL BE NECESSARY ON THE HEELS OF ONGOING
WINTER WEATHER PRODUCTS. KEPT HIGHS BELOW GUIDANCE FOR BOTH TUE
AND WED WITH WIDESPREAD SNOW AND COLD ADVECTION ALOFT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 AM MST MON MAR 2 2015

00Z MODELS INDICATE NORTHWEST FLOW ALOFT BEHIND EXITING TROUGH
AND UPPER RIDGE EXPANDING EAST TOWARD THE GREAT BASIN. A WEAK
SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE CWA THURSDAY MORNING
WITH LITTLE OR NO ASSOCIATED MOISTURE. 700MB WINDS INCREASE TO
50 KT ALONG THE I-80 CORRIDOR BETWEEN ARLINGTON AND CHEYENNE
WEDNESDAY NIGHT/THURSDAY MORNING. OVER THE NORTH SNOWY RANGE
FOOTHILLS/CENTRAL LARAMIE RANGE. THE CENTER OF UPPER RIDGE MOVES
INTO CA/NV FRIDAY WITH LIGHTER NORTHWEST FLOW. THERE ARE MODEL
DIFFERENCES THIS WEEKEND AS THE ECMWF SHOWS A POTENT SHORTWAVE
TROUGH TRACKING SOUTHEAST FROM ID/WESTERN MT ACROSS WY/CO
SATURDAY...PRODUCING LIGHT PRECIPITATION. THE GFS DOES NOT SHOW
THIS FEATURE BUT AMPLIFIES THE NORTHWEST FLOW ALOFT AS SHORTWAVE
ENERGY MOVES ACROSS THE NORTHERN U.S. FOR NOW...LEFT POPS BELOW
15 PERCENT BUT THEY MAY BE INCREASED LATER IF THE GFS TRENDS
TOWARD THE ECMWF. A COLD FRONT WILL MOVE THROUGH THE REGION
SATURDAY. IT DOES NOT LOOK AS COLD BEHIND THE FRONT COMPARED TO
EARLIER MODEL RUNS. HIGHS THURSDAY WILL BE ABOUT 20 DEGREES WARMER
THAN WEDNESDAY AS DOWNSLOPE WEST-NORTHWEST WINDS DEVELOP LEE OF
LARAMIE RANGE. TEMPERATURES FINALLY WARM TO NEAR SEASONAL NORMALS
FRIDAY WITH HIGHS IN THE 30S AND 40S. IT WILL BE A TAD COOLER FOR
THE PLAINS SATURDAY. UPPER RIDGE BUILDS CLOSER WITH DOWNSLOPE
NORTHWEST FLOW KEEPING TEMPERATURES SEASONABLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1031 AM MST MON MAR 2 2015

LIFR CONDS WITH SNOW AND LOW CIGS LIKELY THROUGH THE PD AFFECTING
THE KRWL AREA WHILE ELSEWHERE SCTD MVFR CIGS EXPECTED THROUGH THIS
EVENING.  SFC COLD FRONT WILL MOVE SOUTH ACROSS THE AREA LATE THIS
EVENING AND OVERNIGHT WITH MAINLY IFR CONDITIONS BECOMING WIDESPREAD
LATER TONIGHT INTO TUESDAY MORNING.


&&

.FIRE WEATHER...
ISSUED AT 430 AM MST MON MAR 2 2015

NO FIRE WEATHER CONCERNS. SNOW IS EXPECTED TO DEVELOP TODAY AND
BECOME WIDESPREAD TONIGHT AND TUESDAY. SIGNIFICANT ACCUMULATIONS
ARE POSSIBLE...ESPECIALLY IN THE MOUNTAINS AND LOWER ELEVATION
AREAS WEST OF THE LARAMIE RANGE. THE SNOW WILL GRADUALLY DIMINISH
BY TUESDAY NIGHT. AN ARCTIC COLD FRONT WILL BRING BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS FROM TUESDAY NIGHT THROUGH
WEDNESDAY. MODERATING TEMPERATURES ARE EXPECTED LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR WYZ102-106>108-115>117.

     WINTER STORM WARNING UNTIL 6 PM MST TUESDAY FOR WYZ104-105-
     109>114.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 PM MST
     TUESDAY FOR WYZ101-103.

NE...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR NEZ002-003-095-096.

&&

$$

UPDATE...SML
SHORT TERM...CLH
LONG TERM...MJ
AVIATION...RE
FIRE WEATHER...CLH



  [top]

000
FXUS63 KUNR 021758
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1058 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 224 AM MST MON MAR 2 2015

POTENT WINTER STORM SYSTEM TAKING SHAPE ACROSS THE
WESTERN CONUS AS A STRONG PAC NW IMPULSE WILL PARTIALLY MERGE WITH
AN EJECTING SW CONUS UPPER TROUGH. THIS WILL SET THE STAGE FOR
SNOW/WIND/AND ARCTIC AIR FOR THE REGION...WITH POTENTIALLY DANGEROUS
TRAVEL CONDS TUE MORNING ACROSS MUCH OF THE SD PLAINS. WEAK WAA
ONGOING ACROSS THE REGION AHEAD OF THE ADVANCING UPPER WAVES. LLJ
WILL INTENSIFY THIS MORNING...SUPPORTING GUSTY SOUTHERLY WINDS ON THE
SD PLAINS...ESP OVER SCENTRAL SOUTH DAKOTA. INCREASING CLOUDS
EXPECTED ACROSS THE SOUTHERN HALF...WHICH MAY HAMPER TEMP
POTENTIALS. HAVE SIDED ON THE COOL SIDE OF GUIDANCE FOR THIS...BUT
STILL A MUCH WARMER DAY THAN COMPARED TO THE PREVIOUS FEW. ATTENTION
TURNS TOWARD THE MERGING AFOREMENTIONED TROUGHS. LSA/UVM WILL
SPREAD OVER THE SW HALF OF THE FA THIS EVENING...WITH SNOW
DEVELOPING PER THE ADVANCING SOUTHERN STREAM SYSTEM. SNOW WILL
DEVELOP/OVERSPREAD THE SOUTHERN 2/3 AS FGEN/UPGLIDE PROCESSES ENSUE.
NEARLY ALL MODEL GUIDANCE SUGGEST A CONCENTRATED BAND OF HEAVIER
SNOWFALL ACROSS SCENTRAL SD. THE NAM REMAINS THE FURTHEST NW WITH
THE BAND PLACEMENT IN ADDITION TO BEING THE MOST AGGRESSIVE WITH
QPF. FEEL THE NW PLACEMENT IS POSSIBLE IF PHASING OF THE TWO UPPER
WAVES IS MORE COMPLETE...SUPPORTING A NW TILT TO THE HEIGHT FIELDS.
IN ADDITION...STRONG DYNAMICS COULD SUPPORT A PERIOD OF HEAVIER SNOW
MORE IN LINE WITH THE NAM. SOMETHING THE DAY SHIFT CAN ASSESS.
GENERALLY 2 TO 5 INCHES OF SNOW CAN BE EXPECTED ALONG AND SOUTH OF
I90...WITH HIGHEST AMOUNTS CONCENTRATED IN THE EXPECTED BAND ACROSS
SOUTHERN SD AND IN THE NORTHERN BLACK HILLS PER UPSLOPE. STEEP LL
LAPSE RATES/INCREASING LL FLOW/AND DEEPER INVERSION HEIGHTS WILL
SUPPORT A PERIOD OF STRONG UPSLOPE IN THE NORTHERN BLACK HILLS.
CURRENT THINKING IS WIDESPREAD 3 TO 5 WITH LOCALLY HIGHER AMOUNTS
EXPECTED. MEANWHILE THE STRONGER NW FLOW IMPULSE WILL QUICKLY SHIFT
SE INTO THE REGION...SUPPORTING A STRONG COLD FRONT INTO THE AREA.
STAUNCH PRESSURE RISES IN VERY STRONG CAA WILL SUPPORT INCREASING
NORTHERLY WINDS ON THE SD PLAINS...WITH WINDS INCREASING TO 20 TO 30
MPH WITH GUSTS IN THE 40S.  THIS WILL SUPPORT DANGEROUS TRAVEL CONDS
WHERE PERSISTENT SNOWFALL IS FORECAST. GIVEN ABOVE CONCERNS...HAVE
RETAINED THE WINTER STORM WATCH...DEFERRING HAZARD TYPE TO THE DAY
SHIFT WHEN A BETTER HANDLE ON SNOW AMOUNTS WILL BE ESTABLISHED. DID
PULL THE WATCH BACK TO THE EASTERN BH FOOTHILLS GIVEN CONCERNS ON
POTENTIALLY HIGHER SNOW AMOUNTS WITH WIND. OTHERWISE...ISSUED A
WINTER WX ADV FOR NE WY/THE BH/AND SW SD WHERE GENERALLY 2-5 INCHES
CAN BE EXPECTED. FURTHER NORTH ACROSS THE NW SD ZONES...MINIMAL SNOW
IS EXPECTED WITH WIND BEING THE PRIMARY HAZARD. A WIND ADV MAY BE
NEEDED THERE. SNOW WILL END TUE AFTERNOON AS AN ARCTIC HIGH BUILDS
INTO THE REGION. UPSLOPE SNOWS MAY LINGER INTO THE EVENING.
HOWEVER...DRYING BL CONDS WILL LIKELY SUPPORT A HEAVY WANE. A WEAK
UPSLOPE RESPONSE LOOKS POSSIBLE ONCE AGAIN LATE TUE NIGHT OVER THE
NORTHERN HILLS WITH THE MAIN UPPER WAVE PASSING OVERHEAD. HAVE
RETAINED LOW POPS FOR THIS. COLD CONDS EXPECTED TUE WITH TEMPS
FALLING THROUGH THE DAY INTO THE NIGHT...WITH SUBZERO CONDS ON TRACK
FOR TUE NIGHT...POTENTIALLY NECESSITATING THE NEED FOR WINDCHILL
HEADLINES.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 224 AM MST MON MAR 2 2015

UPPER TROF AXIS SWINGS THROUGH THE NORTHERN PLAINS FOR WEDNESDAY AS
ARCTIC SURFACE HIGH SETTLES IN ACROSS THE DAKOTAS. DRY CONDITIONS
ARE EXPECTED WITH HIGH TEMPERATURES WELL BELOW AVERAGE...MAINLY IN
THE TEENS.

FOR THURSDAY THROUGH EARLY NEXT WEEK...GFS/ECMWF SHOWING UPPER TROF
SHIFTING QUICKLY EAST WITH FAST NORTHWEST FLOW ACROSS THE NORTHERN
PLAINS...AND RIDGING ACROSS THE FAR WESTERN CONUS. DRY CONDITIONS
EXPECTED THROUGH THE EXTENDED PERIOD WITH TEMPERATURES NEAR TO
SLIGHTLY ABOVE AVERAGE.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z TUESDAY
ISSUED AT 1057 AM MST MON MAR 2 2015

VFR CONDITIONS ARE EXPECTED THROUGH THE AFTERNOON IN MOST AREAS. A
STRONG WEATHER DISTURBANCE WILL MOVE INTO NORTHEAST WYOMING AND
SOUTHWEST SOUTH DAKOTA AROUND OR SHORTLY AFTER 00Z...WITH FLIGHT
CONDITIONS DETERIORATING QUICKLY TO IFR/LIFR IN SNOW BY MID EVENING
ACROSS THESE AREAS. SNOW AND IFR/LIFR CONDITIONS WILL SPREAD NORTH
AND EAST ACROSS MOST OF THE CWA OVERNIGHT...WITH THE HEAVIEST
SNOWFALL GENERALLY EXPECTED ACROSS PORTIONS OF THE BLACK HILLS AND
FAR SOUTHWEST SD...TO SOUTH CENTRAL SD. SNOW SHOULD TAPER OFF
QUICKLY IN MOST AREAS EARLY TUESDAY MORNING.

A STRONG ARCTIC FRONT WILL ALSO DROP SOUTH THROUGH THE FORECAST AREA
THIS EVENING...INCREASING NORTH WINDS TO 20 TO 35 MPH WITH HIGHER
GUSTS THROUGH TUESDAY MORNING...PRODUCING BLOWING SNOW AND REDUCED
VISIBILITIES.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 5 PM MST
     TUESDAY FOR SDZ024-025-027>029-041-072.

     WINTER STORM WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON
     FOR SDZ026-030>032-042>044-046-047-049-073-074.

WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 5 PM MST
     TUESDAY FOR WYZ054>058-071.

&&

$$

SHORT TERM...JC
LONG TERM...15
AVIATION...26






000
FXUS63 KUNR 021758
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1058 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 224 AM MST MON MAR 2 2015

POTENT WINTER STORM SYSTEM TAKING SHAPE ACROSS THE
WESTERN CONUS AS A STRONG PAC NW IMPULSE WILL PARTIALLY MERGE WITH
AN EJECTING SW CONUS UPPER TROUGH. THIS WILL SET THE STAGE FOR
SNOW/WIND/AND ARCTIC AIR FOR THE REGION...WITH POTENTIALLY DANGEROUS
TRAVEL CONDS TUE MORNING ACROSS MUCH OF THE SD PLAINS. WEAK WAA
ONGOING ACROSS THE REGION AHEAD OF THE ADVANCING UPPER WAVES. LLJ
WILL INTENSIFY THIS MORNING...SUPPORTING GUSTY SOUTHERLY WINDS ON THE
SD PLAINS...ESP OVER SCENTRAL SOUTH DAKOTA. INCREASING CLOUDS
EXPECTED ACROSS THE SOUTHERN HALF...WHICH MAY HAMPER TEMP
POTENTIALS. HAVE SIDED ON THE COOL SIDE OF GUIDANCE FOR THIS...BUT
STILL A MUCH WARMER DAY THAN COMPARED TO THE PREVIOUS FEW. ATTENTION
TURNS TOWARD THE MERGING AFOREMENTIONED TROUGHS. LSA/UVM WILL
SPREAD OVER THE SW HALF OF THE FA THIS EVENING...WITH SNOW
DEVELOPING PER THE ADVANCING SOUTHERN STREAM SYSTEM. SNOW WILL
DEVELOP/OVERSPREAD THE SOUTHERN 2/3 AS FGEN/UPGLIDE PROCESSES ENSUE.
NEARLY ALL MODEL GUIDANCE SUGGEST A CONCENTRATED BAND OF HEAVIER
SNOWFALL ACROSS SCENTRAL SD. THE NAM REMAINS THE FURTHEST NW WITH
THE BAND PLACEMENT IN ADDITION TO BEING THE MOST AGGRESSIVE WITH
QPF. FEEL THE NW PLACEMENT IS POSSIBLE IF PHASING OF THE TWO UPPER
WAVES IS MORE COMPLETE...SUPPORTING A NW TILT TO THE HEIGHT FIELDS.
IN ADDITION...STRONG DYNAMICS COULD SUPPORT A PERIOD OF HEAVIER SNOW
MORE IN LINE WITH THE NAM. SOMETHING THE DAY SHIFT CAN ASSESS.
GENERALLY 2 TO 5 INCHES OF SNOW CAN BE EXPECTED ALONG AND SOUTH OF
I90...WITH HIGHEST AMOUNTS CONCENTRATED IN THE EXPECTED BAND ACROSS
SOUTHERN SD AND IN THE NORTHERN BLACK HILLS PER UPSLOPE. STEEP LL
LAPSE RATES/INCREASING LL FLOW/AND DEEPER INVERSION HEIGHTS WILL
SUPPORT A PERIOD OF STRONG UPSLOPE IN THE NORTHERN BLACK HILLS.
CURRENT THINKING IS WIDESPREAD 3 TO 5 WITH LOCALLY HIGHER AMOUNTS
EXPECTED. MEANWHILE THE STRONGER NW FLOW IMPULSE WILL QUICKLY SHIFT
SE INTO THE REGION...SUPPORTING A STRONG COLD FRONT INTO THE AREA.
STAUNCH PRESSURE RISES IN VERY STRONG CAA WILL SUPPORT INCREASING
NORTHERLY WINDS ON THE SD PLAINS...WITH WINDS INCREASING TO 20 TO 30
MPH WITH GUSTS IN THE 40S.  THIS WILL SUPPORT DANGEROUS TRAVEL CONDS
WHERE PERSISTENT SNOWFALL IS FORECAST. GIVEN ABOVE CONCERNS...HAVE
RETAINED THE WINTER STORM WATCH...DEFERRING HAZARD TYPE TO THE DAY
SHIFT WHEN A BETTER HANDLE ON SNOW AMOUNTS WILL BE ESTABLISHED. DID
PULL THE WATCH BACK TO THE EASTERN BH FOOTHILLS GIVEN CONCERNS ON
POTENTIALLY HIGHER SNOW AMOUNTS WITH WIND. OTHERWISE...ISSUED A
WINTER WX ADV FOR NE WY/THE BH/AND SW SD WHERE GENERALLY 2-5 INCHES
CAN BE EXPECTED. FURTHER NORTH ACROSS THE NW SD ZONES...MINIMAL SNOW
IS EXPECTED WITH WIND BEING THE PRIMARY HAZARD. A WIND ADV MAY BE
NEEDED THERE. SNOW WILL END TUE AFTERNOON AS AN ARCTIC HIGH BUILDS
INTO THE REGION. UPSLOPE SNOWS MAY LINGER INTO THE EVENING.
HOWEVER...DRYING BL CONDS WILL LIKELY SUPPORT A HEAVY WANE. A WEAK
UPSLOPE RESPONSE LOOKS POSSIBLE ONCE AGAIN LATE TUE NIGHT OVER THE
NORTHERN HILLS WITH THE MAIN UPPER WAVE PASSING OVERHEAD. HAVE
RETAINED LOW POPS FOR THIS. COLD CONDS EXPECTED TUE WITH TEMPS
FALLING THROUGH THE DAY INTO THE NIGHT...WITH SUBZERO CONDS ON TRACK
FOR TUE NIGHT...POTENTIALLY NECESSITATING THE NEED FOR WINDCHILL
HEADLINES.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 224 AM MST MON MAR 2 2015

UPPER TROF AXIS SWINGS THROUGH THE NORTHERN PLAINS FOR WEDNESDAY AS
ARCTIC SURFACE HIGH SETTLES IN ACROSS THE DAKOTAS. DRY CONDITIONS
ARE EXPECTED WITH HIGH TEMPERATURES WELL BELOW AVERAGE...MAINLY IN
THE TEENS.

FOR THURSDAY THROUGH EARLY NEXT WEEK...GFS/ECMWF SHOWING UPPER TROF
SHIFTING QUICKLY EAST WITH FAST NORTHWEST FLOW ACROSS THE NORTHERN
PLAINS...AND RIDGING ACROSS THE FAR WESTERN CONUS. DRY CONDITIONS
EXPECTED THROUGH THE EXTENDED PERIOD WITH TEMPERATURES NEAR TO
SLIGHTLY ABOVE AVERAGE.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z TUESDAY
ISSUED AT 1057 AM MST MON MAR 2 2015

VFR CONDITIONS ARE EXPECTED THROUGH THE AFTERNOON IN MOST AREAS. A
STRONG WEATHER DISTURBANCE WILL MOVE INTO NORTHEAST WYOMING AND
SOUTHWEST SOUTH DAKOTA AROUND OR SHORTLY AFTER 00Z...WITH FLIGHT
CONDITIONS DETERIORATING QUICKLY TO IFR/LIFR IN SNOW BY MID EVENING
ACROSS THESE AREAS. SNOW AND IFR/LIFR CONDITIONS WILL SPREAD NORTH
AND EAST ACROSS MOST OF THE CWA OVERNIGHT...WITH THE HEAVIEST
SNOWFALL GENERALLY EXPECTED ACROSS PORTIONS OF THE BLACK HILLS AND
FAR SOUTHWEST SD...TO SOUTH CENTRAL SD. SNOW SHOULD TAPER OFF
QUICKLY IN MOST AREAS EARLY TUESDAY MORNING.

A STRONG ARCTIC FRONT WILL ALSO DROP SOUTH THROUGH THE FORECAST AREA
THIS EVENING...INCREASING NORTH WINDS TO 20 TO 35 MPH WITH HIGHER
GUSTS THROUGH TUESDAY MORNING...PRODUCING BLOWING SNOW AND REDUCED
VISIBILITIES.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 5 PM MST
     TUESDAY FOR SDZ024-025-027>029-041-072.

     WINTER STORM WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON
     FOR SDZ026-030>032-042>044-046-047-049-073-074.

WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 5 PM MST
     TUESDAY FOR WYZ054>058-071.

&&

$$

SHORT TERM...JC
LONG TERM...15
AVIATION...26







000
FXUS63 KUNR 021758
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1058 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 224 AM MST MON MAR 2 2015

POTENT WINTER STORM SYSTEM TAKING SHAPE ACROSS THE
WESTERN CONUS AS A STRONG PAC NW IMPULSE WILL PARTIALLY MERGE WITH
AN EJECTING SW CONUS UPPER TROUGH. THIS WILL SET THE STAGE FOR
SNOW/WIND/AND ARCTIC AIR FOR THE REGION...WITH POTENTIALLY DANGEROUS
TRAVEL CONDS TUE MORNING ACROSS MUCH OF THE SD PLAINS. WEAK WAA
ONGOING ACROSS THE REGION AHEAD OF THE ADVANCING UPPER WAVES. LLJ
WILL INTENSIFY THIS MORNING...SUPPORTING GUSTY SOUTHERLY WINDS ON THE
SD PLAINS...ESP OVER SCENTRAL SOUTH DAKOTA. INCREASING CLOUDS
EXPECTED ACROSS THE SOUTHERN HALF...WHICH MAY HAMPER TEMP
POTENTIALS. HAVE SIDED ON THE COOL SIDE OF GUIDANCE FOR THIS...BUT
STILL A MUCH WARMER DAY THAN COMPARED TO THE PREVIOUS FEW. ATTENTION
TURNS TOWARD THE MERGING AFOREMENTIONED TROUGHS. LSA/UVM WILL
SPREAD OVER THE SW HALF OF THE FA THIS EVENING...WITH SNOW
DEVELOPING PER THE ADVANCING SOUTHERN STREAM SYSTEM. SNOW WILL
DEVELOP/OVERSPREAD THE SOUTHERN 2/3 AS FGEN/UPGLIDE PROCESSES ENSUE.
NEARLY ALL MODEL GUIDANCE SUGGEST A CONCENTRATED BAND OF HEAVIER
SNOWFALL ACROSS SCENTRAL SD. THE NAM REMAINS THE FURTHEST NW WITH
THE BAND PLACEMENT IN ADDITION TO BEING THE MOST AGGRESSIVE WITH
QPF. FEEL THE NW PLACEMENT IS POSSIBLE IF PHASING OF THE TWO UPPER
WAVES IS MORE COMPLETE...SUPPORTING A NW TILT TO THE HEIGHT FIELDS.
IN ADDITION...STRONG DYNAMICS COULD SUPPORT A PERIOD OF HEAVIER SNOW
MORE IN LINE WITH THE NAM. SOMETHING THE DAY SHIFT CAN ASSESS.
GENERALLY 2 TO 5 INCHES OF SNOW CAN BE EXPECTED ALONG AND SOUTH OF
I90...WITH HIGHEST AMOUNTS CONCENTRATED IN THE EXPECTED BAND ACROSS
SOUTHERN SD AND IN THE NORTHERN BLACK HILLS PER UPSLOPE. STEEP LL
LAPSE RATES/INCREASING LL FLOW/AND DEEPER INVERSION HEIGHTS WILL
SUPPORT A PERIOD OF STRONG UPSLOPE IN THE NORTHERN BLACK HILLS.
CURRENT THINKING IS WIDESPREAD 3 TO 5 WITH LOCALLY HIGHER AMOUNTS
EXPECTED. MEANWHILE THE STRONGER NW FLOW IMPULSE WILL QUICKLY SHIFT
SE INTO THE REGION...SUPPORTING A STRONG COLD FRONT INTO THE AREA.
STAUNCH PRESSURE RISES IN VERY STRONG CAA WILL SUPPORT INCREASING
NORTHERLY WINDS ON THE SD PLAINS...WITH WINDS INCREASING TO 20 TO 30
MPH WITH GUSTS IN THE 40S.  THIS WILL SUPPORT DANGEROUS TRAVEL CONDS
WHERE PERSISTENT SNOWFALL IS FORECAST. GIVEN ABOVE CONCERNS...HAVE
RETAINED THE WINTER STORM WATCH...DEFERRING HAZARD TYPE TO THE DAY
SHIFT WHEN A BETTER HANDLE ON SNOW AMOUNTS WILL BE ESTABLISHED. DID
PULL THE WATCH BACK TO THE EASTERN BH FOOTHILLS GIVEN CONCERNS ON
POTENTIALLY HIGHER SNOW AMOUNTS WITH WIND. OTHERWISE...ISSUED A
WINTER WX ADV FOR NE WY/THE BH/AND SW SD WHERE GENERALLY 2-5 INCHES
CAN BE EXPECTED. FURTHER NORTH ACROSS THE NW SD ZONES...MINIMAL SNOW
IS EXPECTED WITH WIND BEING THE PRIMARY HAZARD. A WIND ADV MAY BE
NEEDED THERE. SNOW WILL END TUE AFTERNOON AS AN ARCTIC HIGH BUILDS
INTO THE REGION. UPSLOPE SNOWS MAY LINGER INTO THE EVENING.
HOWEVER...DRYING BL CONDS WILL LIKELY SUPPORT A HEAVY WANE. A WEAK
UPSLOPE RESPONSE LOOKS POSSIBLE ONCE AGAIN LATE TUE NIGHT OVER THE
NORTHERN HILLS WITH THE MAIN UPPER WAVE PASSING OVERHEAD. HAVE
RETAINED LOW POPS FOR THIS. COLD CONDS EXPECTED TUE WITH TEMPS
FALLING THROUGH THE DAY INTO THE NIGHT...WITH SUBZERO CONDS ON TRACK
FOR TUE NIGHT...POTENTIALLY NECESSITATING THE NEED FOR WINDCHILL
HEADLINES.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 224 AM MST MON MAR 2 2015

UPPER TROF AXIS SWINGS THROUGH THE NORTHERN PLAINS FOR WEDNESDAY AS
ARCTIC SURFACE HIGH SETTLES IN ACROSS THE DAKOTAS. DRY CONDITIONS
ARE EXPECTED WITH HIGH TEMPERATURES WELL BELOW AVERAGE...MAINLY IN
THE TEENS.

FOR THURSDAY THROUGH EARLY NEXT WEEK...GFS/ECMWF SHOWING UPPER TROF
SHIFTING QUICKLY EAST WITH FAST NORTHWEST FLOW ACROSS THE NORTHERN
PLAINS...AND RIDGING ACROSS THE FAR WESTERN CONUS. DRY CONDITIONS
EXPECTED THROUGH THE EXTENDED PERIOD WITH TEMPERATURES NEAR TO
SLIGHTLY ABOVE AVERAGE.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z TUESDAY
ISSUED AT 1057 AM MST MON MAR 2 2015

VFR CONDITIONS ARE EXPECTED THROUGH THE AFTERNOON IN MOST AREAS. A
STRONG WEATHER DISTURBANCE WILL MOVE INTO NORTHEAST WYOMING AND
SOUTHWEST SOUTH DAKOTA AROUND OR SHORTLY AFTER 00Z...WITH FLIGHT
CONDITIONS DETERIORATING QUICKLY TO IFR/LIFR IN SNOW BY MID EVENING
ACROSS THESE AREAS. SNOW AND IFR/LIFR CONDITIONS WILL SPREAD NORTH
AND EAST ACROSS MOST OF THE CWA OVERNIGHT...WITH THE HEAVIEST
SNOWFALL GENERALLY EXPECTED ACROSS PORTIONS OF THE BLACK HILLS AND
FAR SOUTHWEST SD...TO SOUTH CENTRAL SD. SNOW SHOULD TAPER OFF
QUICKLY IN MOST AREAS EARLY TUESDAY MORNING.

A STRONG ARCTIC FRONT WILL ALSO DROP SOUTH THROUGH THE FORECAST AREA
THIS EVENING...INCREASING NORTH WINDS TO 20 TO 35 MPH WITH HIGHER
GUSTS THROUGH TUESDAY MORNING...PRODUCING BLOWING SNOW AND REDUCED
VISIBILITIES.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 5 PM MST
     TUESDAY FOR SDZ024-025-027>029-041-072.

     WINTER STORM WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON
     FOR SDZ026-030>032-042>044-046-047-049-073-074.

WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 5 PM MST
     TUESDAY FOR WYZ054>058-071.

&&

$$

SHORT TERM...JC
LONG TERM...15
AVIATION...26







000
FXUS63 KUNR 021758
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1058 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 224 AM MST MON MAR 2 2015

POTENT WINTER STORM SYSTEM TAKING SHAPE ACROSS THE
WESTERN CONUS AS A STRONG PAC NW IMPULSE WILL PARTIALLY MERGE WITH
AN EJECTING SW CONUS UPPER TROUGH. THIS WILL SET THE STAGE FOR
SNOW/WIND/AND ARCTIC AIR FOR THE REGION...WITH POTENTIALLY DANGEROUS
TRAVEL CONDS TUE MORNING ACROSS MUCH OF THE SD PLAINS. WEAK WAA
ONGOING ACROSS THE REGION AHEAD OF THE ADVANCING UPPER WAVES. LLJ
WILL INTENSIFY THIS MORNING...SUPPORTING GUSTY SOUTHERLY WINDS ON THE
SD PLAINS...ESP OVER SCENTRAL SOUTH DAKOTA. INCREASING CLOUDS
EXPECTED ACROSS THE SOUTHERN HALF...WHICH MAY HAMPER TEMP
POTENTIALS. HAVE SIDED ON THE COOL SIDE OF GUIDANCE FOR THIS...BUT
STILL A MUCH WARMER DAY THAN COMPARED TO THE PREVIOUS FEW. ATTENTION
TURNS TOWARD THE MERGING AFOREMENTIONED TROUGHS. LSA/UVM WILL
SPREAD OVER THE SW HALF OF THE FA THIS EVENING...WITH SNOW
DEVELOPING PER THE ADVANCING SOUTHERN STREAM SYSTEM. SNOW WILL
DEVELOP/OVERSPREAD THE SOUTHERN 2/3 AS FGEN/UPGLIDE PROCESSES ENSUE.
NEARLY ALL MODEL GUIDANCE SUGGEST A CONCENTRATED BAND OF HEAVIER
SNOWFALL ACROSS SCENTRAL SD. THE NAM REMAINS THE FURTHEST NW WITH
THE BAND PLACEMENT IN ADDITION TO BEING THE MOST AGGRESSIVE WITH
QPF. FEEL THE NW PLACEMENT IS POSSIBLE IF PHASING OF THE TWO UPPER
WAVES IS MORE COMPLETE...SUPPORTING A NW TILT TO THE HEIGHT FIELDS.
IN ADDITION...STRONG DYNAMICS COULD SUPPORT A PERIOD OF HEAVIER SNOW
MORE IN LINE WITH THE NAM. SOMETHING THE DAY SHIFT CAN ASSESS.
GENERALLY 2 TO 5 INCHES OF SNOW CAN BE EXPECTED ALONG AND SOUTH OF
I90...WITH HIGHEST AMOUNTS CONCENTRATED IN THE EXPECTED BAND ACROSS
SOUTHERN SD AND IN THE NORTHERN BLACK HILLS PER UPSLOPE. STEEP LL
LAPSE RATES/INCREASING LL FLOW/AND DEEPER INVERSION HEIGHTS WILL
SUPPORT A PERIOD OF STRONG UPSLOPE IN THE NORTHERN BLACK HILLS.
CURRENT THINKING IS WIDESPREAD 3 TO 5 WITH LOCALLY HIGHER AMOUNTS
EXPECTED. MEANWHILE THE STRONGER NW FLOW IMPULSE WILL QUICKLY SHIFT
SE INTO THE REGION...SUPPORTING A STRONG COLD FRONT INTO THE AREA.
STAUNCH PRESSURE RISES IN VERY STRONG CAA WILL SUPPORT INCREASING
NORTHERLY WINDS ON THE SD PLAINS...WITH WINDS INCREASING TO 20 TO 30
MPH WITH GUSTS IN THE 40S.  THIS WILL SUPPORT DANGEROUS TRAVEL CONDS
WHERE PERSISTENT SNOWFALL IS FORECAST. GIVEN ABOVE CONCERNS...HAVE
RETAINED THE WINTER STORM WATCH...DEFERRING HAZARD TYPE TO THE DAY
SHIFT WHEN A BETTER HANDLE ON SNOW AMOUNTS WILL BE ESTABLISHED. DID
PULL THE WATCH BACK TO THE EASTERN BH FOOTHILLS GIVEN CONCERNS ON
POTENTIALLY HIGHER SNOW AMOUNTS WITH WIND. OTHERWISE...ISSUED A
WINTER WX ADV FOR NE WY/THE BH/AND SW SD WHERE GENERALLY 2-5 INCHES
CAN BE EXPECTED. FURTHER NORTH ACROSS THE NW SD ZONES...MINIMAL SNOW
IS EXPECTED WITH WIND BEING THE PRIMARY HAZARD. A WIND ADV MAY BE
NEEDED THERE. SNOW WILL END TUE AFTERNOON AS AN ARCTIC HIGH BUILDS
INTO THE REGION. UPSLOPE SNOWS MAY LINGER INTO THE EVENING.
HOWEVER...DRYING BL CONDS WILL LIKELY SUPPORT A HEAVY WANE. A WEAK
UPSLOPE RESPONSE LOOKS POSSIBLE ONCE AGAIN LATE TUE NIGHT OVER THE
NORTHERN HILLS WITH THE MAIN UPPER WAVE PASSING OVERHEAD. HAVE
RETAINED LOW POPS FOR THIS. COLD CONDS EXPECTED TUE WITH TEMPS
FALLING THROUGH THE DAY INTO THE NIGHT...WITH SUBZERO CONDS ON TRACK
FOR TUE NIGHT...POTENTIALLY NECESSITATING THE NEED FOR WINDCHILL
HEADLINES.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 224 AM MST MON MAR 2 2015

UPPER TROF AXIS SWINGS THROUGH THE NORTHERN PLAINS FOR WEDNESDAY AS
ARCTIC SURFACE HIGH SETTLES IN ACROSS THE DAKOTAS. DRY CONDITIONS
ARE EXPECTED WITH HIGH TEMPERATURES WELL BELOW AVERAGE...MAINLY IN
THE TEENS.

FOR THURSDAY THROUGH EARLY NEXT WEEK...GFS/ECMWF SHOWING UPPER TROF
SHIFTING QUICKLY EAST WITH FAST NORTHWEST FLOW ACROSS THE NORTHERN
PLAINS...AND RIDGING ACROSS THE FAR WESTERN CONUS. DRY CONDITIONS
EXPECTED THROUGH THE EXTENDED PERIOD WITH TEMPERATURES NEAR TO
SLIGHTLY ABOVE AVERAGE.

&&

.AVIATION...FOR THE 18Z TAFS THROUGH 18Z TUESDAY
ISSUED AT 1057 AM MST MON MAR 2 2015

VFR CONDITIONS ARE EXPECTED THROUGH THE AFTERNOON IN MOST AREAS. A
STRONG WEATHER DISTURBANCE WILL MOVE INTO NORTHEAST WYOMING AND
SOUTHWEST SOUTH DAKOTA AROUND OR SHORTLY AFTER 00Z...WITH FLIGHT
CONDITIONS DETERIORATING QUICKLY TO IFR/LIFR IN SNOW BY MID EVENING
ACROSS THESE AREAS. SNOW AND IFR/LIFR CONDITIONS WILL SPREAD NORTH
AND EAST ACROSS MOST OF THE CWA OVERNIGHT...WITH THE HEAVIEST
SNOWFALL GENERALLY EXPECTED ACROSS PORTIONS OF THE BLACK HILLS AND
FAR SOUTHWEST SD...TO SOUTH CENTRAL SD. SNOW SHOULD TAPER OFF
QUICKLY IN MOST AREAS EARLY TUESDAY MORNING.

A STRONG ARCTIC FRONT WILL ALSO DROP SOUTH THROUGH THE FORECAST AREA
THIS EVENING...INCREASING NORTH WINDS TO 20 TO 35 MPH WITH HIGHER
GUSTS THROUGH TUESDAY MORNING...PRODUCING BLOWING SNOW AND REDUCED
VISIBILITIES.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 5 PM MST
     TUESDAY FOR SDZ024-025-027>029-041-072.

     WINTER STORM WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON
     FOR SDZ026-030>032-042>044-046-047-049-073-074.

WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 5 PM MST
     TUESDAY FOR WYZ054>058-071.

&&

$$

SHORT TERM...JC
LONG TERM...15
AVIATION...26





  [top]

000
FXUS65 KRIW 021750 CCA
AFDRIW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RIVERTON WY
1050 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
AN EXPANSIVE AREA OF SNOWFALL WILL PERSIST ACROSS THE EAST HALF OF
SWEETWATER COUNTY THROUGH 00Z TODAY RESULTING IN WIDESPREAD IFR/MVFR
CONDITIONS AND MTN OBSCURATIONS. VFR CONDITIONS...FL SCT-BKN200-250
WILL CONTINUE NORTH AND WEST OF THERE THROUGH 21Z THIS AFTERNOON.
A LOW PRESSURE SYSTEM LIFTING NE ACROSS THE GREAT BASIN WILL PUSH
SCT MVFR -SHRASN NORTH TO A VCNTY KLND-KCPR LINE 21Z TODAY-00Z TUE.
CONDITIONS WILL THEN DETERIORATE RAPIDLY AFTER 00Z TUE AS A COLD
FRONT PUSHES DOWN FROM THE NORTH BRINGING WIDESPREAD MVFR/IFR -SN
AND MTN OBSCURATIONS ACROSS THE AREA BY 4Z TUE ALONG WITH INCREASING
NORTH WIND AND SOME BLOWING SNOW.  THE HEAVIEST SNOWFALL AND AREAS OF
LIFR CONDITIONS WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE AS
THE SNOWFALL AND LOW CIGS ALREADY IN PLACE ACROSS THE EAST HALF OF
SWEETWATER COUNTY CONTINUE TO INCREASE AND LOWER RESPECTIVELY. THESE
CONDITIONS WILL PERSIST THROUGH 12Z TUE. THESE CONDITIONS WILL BEGIN
TO IMPROVE FROM NORTHWEST TO SOUTHEAST AFTER 12Z TUESDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
THE UPPER LEVEL DISTURBANCE BRINGING AN INITIAL BAND OF MVFR/IFR -SN
NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 WILL
IMPROVEMENT SOMEWHAT BY 19Z THIS AFTERNOON. THEN MORE WIDESPREAD
PERSISTENT IFR SNOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING
AROUND 20Z TODAY AND PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN
COLD FRONT PUSHING DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG
THE DIVIDE THIS EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD
MVFR/IFR -SN BY 06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.
KRKS WILL BE IN THE BATTLE ZONE BETWEEN THE NORTHEAST AND WEST WINDS
FOR MUCH OF TUESDAY WITH WEST WINDS WEST OF THERE AND NORTHEAST
WINDS NORTH AND EAST OF THERE. THE SNOWFALL AND CIGS WILL DECREASE
AND LIFT RESPECTIVELY FROM NORTHWEST TO SOUTHEAST DURING THE DAY
TUESDAY.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...LIPSON
FIRE WEATHER...BRANHAM












000
FXUS65 KRIW 021750 CCA
AFDRIW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RIVERTON WY
1050 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
AN EXPANSIVE AREA OF SNOWFALL WILL PERSIST ACROSS THE EAST HALF OF
SWEETWATER COUNTY THROUGH 00Z TODAY RESULTING IN WIDESPREAD IFR/MVFR
CONDITIONS AND MTN OBSCURATIONS. VFR CONDITIONS...FL SCT-BKN200-250
WILL CONTINUE NORTH AND WEST OF THERE THROUGH 21Z THIS AFTERNOON.
A LOW PRESSURE SYSTEM LIFTING NE ACROSS THE GREAT BASIN WILL PUSH
SCT MVFR -SHRASN NORTH TO A VCNTY KLND-KCPR LINE 21Z TODAY-00Z TUE.
CONDITIONS WILL THEN DETERIORATE RAPIDLY AFTER 00Z TUE AS A COLD
FRONT PUSHES DOWN FROM THE NORTH BRINGING WIDESPREAD MVFR/IFR -SN
AND MTN OBSCURATIONS ACROSS THE AREA BY 4Z TUE ALONG WITH INCREASING
NORTH WIND AND SOME BLOWING SNOW.  THE HEAVIEST SNOWFALL AND AREAS OF
LIFR CONDITIONS WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE AS
THE SNOWFALL AND LOW CIGS ALREADY IN PLACE ACROSS THE EAST HALF OF
SWEETWATER COUNTY CONTINUE TO INCREASE AND LOWER RESPECTIVELY. THESE
CONDITIONS WILL PERSIST THROUGH 12Z TUE. THESE CONDITIONS WILL BEGIN
TO IMPROVE FROM NORTHWEST TO SOUTHEAST AFTER 12Z TUESDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
THE UPPER LEVEL DISTURBANCE BRINGING AN INITIAL BAND OF MVFR/IFR -SN
NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 WILL
IMPROVEMENT SOMEWHAT BY 19Z THIS AFTERNOON. THEN MORE WIDESPREAD
PERSISTENT IFR SNOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING
AROUND 20Z TODAY AND PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN
COLD FRONT PUSHING DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG
THE DIVIDE THIS EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD
MVFR/IFR -SN BY 06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.
KRKS WILL BE IN THE BATTLE ZONE BETWEEN THE NORTHEAST AND WEST WINDS
FOR MUCH OF TUESDAY WITH WEST WINDS WEST OF THERE AND NORTHEAST
WINDS NORTH AND EAST OF THERE. THE SNOWFALL AND CIGS WILL DECREASE
AND LIFT RESPECTIVELY FROM NORTHWEST TO SOUTHEAST DURING THE DAY
TUESDAY.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...LIPSON
FIRE WEATHER...BRANHAM












000
FXUS65 KRIW 021750 CCA
AFDRIW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RIVERTON WY
1050 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
AN EXPANSIVE AREA OF SNOWFALL WILL PERSIST ACROSS THE EAST HALF OF
SWEETWATER COUNTY THROUGH 00Z TODAY RESULTING IN WIDESPREAD IFR/MVFR
CONDITIONS AND MTN OBSCURATIONS. VFR CONDITIONS...FL SCT-BKN200-250
WILL CONTINUE NORTH AND WEST OF THERE THROUGH 21Z THIS AFTERNOON.
A LOW PRESSURE SYSTEM LIFTING NE ACROSS THE GREAT BASIN WILL PUSH
SCT MVFR -SHRASN NORTH TO A VCNTY KLND-KCPR LINE 21Z TODAY-00Z TUE.
CONDITIONS WILL THEN DETERIORATE RAPIDLY AFTER 00Z TUE AS A COLD
FRONT PUSHES DOWN FROM THE NORTH BRINGING WIDESPREAD MVFR/IFR -SN
AND MTN OBSCURATIONS ACROSS THE AREA BY 4Z TUE ALONG WITH INCREASING
NORTH WIND AND SOME BLOWING SNOW.  THE HEAVIEST SNOWFALL AND AREAS OF
LIFR CONDITIONS WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE AS
THE SNOWFALL AND LOW CIGS ALREADY IN PLACE ACROSS THE EAST HALF OF
SWEETWATER COUNTY CONTINUE TO INCREASE AND LOWER RESPECTIVELY. THESE
CONDITIONS WILL PERSIST THROUGH 12Z TUE. THESE CONDITIONS WILL BEGIN
TO IMPROVE FROM NORTHWEST TO SOUTHEAST AFTER 12Z TUESDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
THE UPPER LEVEL DISTURBANCE BRINGING AN INITIAL BAND OF MVFR/IFR -SN
NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 WILL
IMPROVEMENT SOMEWHAT BY 19Z THIS AFTERNOON. THEN MORE WIDESPREAD
PERSISTENT IFR SNOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING
AROUND 20Z TODAY AND PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN
COLD FRONT PUSHING DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG
THE DIVIDE THIS EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD
MVFR/IFR -SN BY 06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.
KRKS WILL BE IN THE BATTLE ZONE BETWEEN THE NORTHEAST AND WEST WINDS
FOR MUCH OF TUESDAY WITH WEST WINDS WEST OF THERE AND NORTHEAST
WINDS NORTH AND EAST OF THERE. THE SNOWFALL AND CIGS WILL DECREASE
AND LIFT RESPECTIVELY FROM NORTHWEST TO SOUTHEAST DURING THE DAY
TUESDAY.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...LIPSON
FIRE WEATHER...BRANHAM












000
FXUS65 KRIW 021750 CCA
AFDRIW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RIVERTON WY
1050 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
AN EXPANSIVE AREA OF SNOWFALL WILL PERSIST ACROSS THE EAST HALF OF
SWEETWATER COUNTY THROUGH 00Z TODAY RESULTING IN WIDESPREAD IFR/MVFR
CONDITIONS AND MTN OBSCURATIONS. VFR CONDITIONS...FL SCT-BKN200-250
WILL CONTINUE NORTH AND WEST OF THERE THROUGH 21Z THIS AFTERNOON.
A LOW PRESSURE SYSTEM LIFTING NE ACROSS THE GREAT BASIN WILL PUSH
SCT MVFR -SHRASN NORTH TO A VCNTY KLND-KCPR LINE 21Z TODAY-00Z TUE.
CONDITIONS WILL THEN DETERIORATE RAPIDLY AFTER 00Z TUE AS A COLD
FRONT PUSHES DOWN FROM THE NORTH BRINGING WIDESPREAD MVFR/IFR -SN
AND MTN OBSCURATIONS ACROSS THE AREA BY 4Z TUE ALONG WITH INCREASING
NORTH WIND AND SOME BLOWING SNOW.  THE HEAVIEST SNOWFALL AND AREAS OF
LIFR CONDITIONS WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE AS
THE SNOWFALL AND LOW CIGS ALREADY IN PLACE ACROSS THE EAST HALF OF
SWEETWATER COUNTY CONTINUE TO INCREASE AND LOWER RESPECTIVELY. THESE
CONDITIONS WILL PERSIST THROUGH 12Z TUE. THESE CONDITIONS WILL BEGIN
TO IMPROVE FROM NORTHWEST TO SOUTHEAST AFTER 12Z TUESDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
THE UPPER LEVEL DISTURBANCE BRINGING AN INITIAL BAND OF MVFR/IFR -SN
NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 WILL
IMPROVEMENT SOMEWHAT BY 19Z THIS AFTERNOON. THEN MORE WIDESPREAD
PERSISTENT IFR SNOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING
AROUND 20Z TODAY AND PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN
COLD FRONT PUSHING DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG
THE DIVIDE THIS EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD
MVFR/IFR -SN BY 06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.
KRKS WILL BE IN THE BATTLE ZONE BETWEEN THE NORTHEAST AND WEST WINDS
FOR MUCH OF TUESDAY WITH WEST WINDS WEST OF THERE AND NORTHEAST
WINDS NORTH AND EAST OF THERE. THE SNOWFALL AND CIGS WILL DECREASE
AND LIFT RESPECTIVELY FROM NORTHWEST TO SOUTHEAST DURING THE DAY
TUESDAY.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...LIPSON
FIRE WEATHER...BRANHAM












000
FXUS65 KRIW 021750 CCA
AFDRIW

AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE RIVERTON WY
1050 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
AN EXPANSIVE AREA OF SNOWFALL WILL PERSIST ACROSS THE EAST HALF OF
SWEETWATER COUNTY THROUGH 00Z TODAY RESULTING IN WIDESPREAD IFR/MVFR
CONDITIONS AND MTN OBSCURATIONS. VFR CONDITIONS...FL SCT-BKN200-250
WILL CONTINUE NORTH AND WEST OF THERE THROUGH 21Z THIS AFTERNOON.
A LOW PRESSURE SYSTEM LIFTING NE ACROSS THE GREAT BASIN WILL PUSH
SCT MVFR -SHRASN NORTH TO A VCNTY KLND-KCPR LINE 21Z TODAY-00Z TUE.
CONDITIONS WILL THEN DETERIORATE RAPIDLY AFTER 00Z TUE AS A COLD
FRONT PUSHES DOWN FROM THE NORTH BRINGING WIDESPREAD MVFR/IFR -SN
AND MTN OBSCURATIONS ACROSS THE AREA BY 4Z TUE ALONG WITH INCREASING
NORTH WIND AND SOME BLOWING SNOW.  THE HEAVIEST SNOWFALL AND AREAS OF
LIFR CONDITIONS WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE AS
THE SNOWFALL AND LOW CIGS ALREADY IN PLACE ACROSS THE EAST HALF OF
SWEETWATER COUNTY CONTINUE TO INCREASE AND LOWER RESPECTIVELY. THESE
CONDITIONS WILL PERSIST THROUGH 12Z TUE. THESE CONDITIONS WILL BEGIN
TO IMPROVE FROM NORTHWEST TO SOUTHEAST AFTER 12Z TUESDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
THE UPPER LEVEL DISTURBANCE BRINGING AN INITIAL BAND OF MVFR/IFR -SN
NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 WILL
IMPROVEMENT SOMEWHAT BY 19Z THIS AFTERNOON. THEN MORE WIDESPREAD
PERSISTENT IFR SNOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING
AROUND 20Z TODAY AND PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN
COLD FRONT PUSHING DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG
THE DIVIDE THIS EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD
MVFR/IFR -SN BY 06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.
KRKS WILL BE IN THE BATTLE ZONE BETWEEN THE NORTHEAST AND WEST WINDS
FOR MUCH OF TUESDAY WITH WEST WINDS WEST OF THERE AND NORTHEAST
WINDS NORTH AND EAST OF THERE. THE SNOWFALL AND CIGS WILL DECREASE
AND LIFT RESPECTIVELY FROM NORTHWEST TO SOUTHEAST DURING THE DAY
TUESDAY.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...LIPSON
FIRE WEATHER...BRANHAM












000
FXUS65 KRIW 021749
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
236 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
AN EXPANSIVE AREA OF SNOWFALL WILL PERSIST ACROSS THE EAST HALF OF
SWEETWATER COUNTY THROUGH 00Z TODAY RESULTING IN WIDESPREAD IFR/MVFR
CONDITIONS AND MTN OBSCURATIONS. VFR CONDITIONS...FL SCT-BKN200-250
WILL CONTINUE NORTH AND WEST OF THERE THROUGH 21Z THIS AFTERNOON.
A LOW PRESSURE SYSTEM LIFTING NE ACROSS THE GREAT BASIN WILL PUSH
SCT MVFR -SHRASN NORTH TO A VCNTY KLND-KCPR LINE 21Z TODAY-00Z TUE.
CONDITIONS WILL THEN DETERIORATE RAPIDLY AFTER 00Z TUE AS A COLD
FRONT PUSHES DOWN FROM THE NORTH BRINGING WIDESPREAD MVFR/IFR -SN
AND MTN OBSCURATIONS ACROSS THE AREA BY 4Z TUE ALONG WITH INCREASING
NORTH WIND AND SOME BLOWING SNOW.  THE HEAVIEST SNOWFALL AND AREAS OF
LIFR CONDITIONS WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE AS
THE SNOWFALL AND LOW CIGS ALREADY IN PLACE ACROSS THE EAST HALF OF
SWEETWATER COUNTY CONTINUE TO INCREASE AND LOWER RESPECTIVELY. THESE
CONDITIONS WILL PERSIST THROUGH 12Z TUE. THESE CONDITIONS WILL BEGIN
TO IMPROVE FROM NORTHWEST TO SOUTHEAST AFTER 12Z TUESDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
THE UPPER LEVEL DISTURBANCE BRINGING AN INITIAL BAND OF MVFR/IFR -SN
NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 WILL
IMPROVEMENT SOMEWHAT BY 19Z THIS AFTERNOON. THEN MORE WIDESPREAD
PERSISTENT IFR SNOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING
AROUND 20Z TODAY AND PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN
COLD FRONT PUSHING DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG
THE DIVIDE THIS EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD
MVFR/IFR -SN BY 06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.
KRKS WILL BE IN THE BATTLE ZONE BETWEEN THE NORTHEAST AND WEST WINDS
FOR MUCH OF TUESDAY WITH WEST WINDS WEST OF THERE AND NORTHEAST
WINDS NORTH AND EAST OF THERE. THE SNOWFALL AND CIGS WILL DECREASE
AND LIFT RESPECTIVELY FROM NORTHWEST TO SOUTHEAST DURING THE DAY
TUESDAY.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...LIPSON
FIRE WEATHER...BRANHAM












000
FXUS65 KRIW 021749
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
236 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
AN EXPANSIVE AREA OF SNOWFALL WILL PERSIST ACROSS THE EAST HALF OF
SWEETWATER COUNTY THROUGH 00Z TODAY RESULTING IN WIDESPREAD IFR/MVFR
CONDITIONS AND MTN OBSCURATIONS. VFR CONDITIONS...FL SCT-BKN200-250
WILL CONTINUE NORTH AND WEST OF THERE THROUGH 21Z THIS AFTERNOON.
A LOW PRESSURE SYSTEM LIFTING NE ACROSS THE GREAT BASIN WILL PUSH
SCT MVFR -SHRASN NORTH TO A VCNTY KLND-KCPR LINE 21Z TODAY-00Z TUE.
CONDITIONS WILL THEN DETERIORATE RAPIDLY AFTER 00Z TUE AS A COLD
FRONT PUSHES DOWN FROM THE NORTH BRINGING WIDESPREAD MVFR/IFR -SN
AND MTN OBSCURATIONS ACROSS THE AREA BY 4Z TUE ALONG WITH INCREASING
NORTH WIND AND SOME BLOWING SNOW.  THE HEAVIEST SNOWFALL AND AREAS OF
LIFR CONDITIONS WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE AS
THE SNOWFALL AND LOW CIGS ALREADY IN PLACE ACROSS THE EAST HALF OF
SWEETWATER COUNTY CONTINUE TO INCREASE AND LOWER RESPECTIVELY. THESE
CONDITIONS WILL PERSIST THROUGH 12Z TUE. THESE CONDITIONS WILL BEGIN
TO IMPROVE FROM NORTHWEST TO SOUTHEAST AFTER 12Z TUESDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
THE UPPER LEVEL DISTURBANCE BRINGING AN INITIAL BAND OF MVFR/IFR -SN
NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 WILL
IMPROVEMENT SOMEWHAT BY 19Z THIS AFTERNOON. THEN MORE WIDESPREAD
PERSISTENT IFR SNOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING
AROUND 20Z TODAY AND PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN
COLD FRONT PUSHING DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG
THE DIVIDE THIS EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD
MVFR/IFR -SN BY 06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.
KRKS WILL BE IN THE BATTLE ZONE BETWEEN THE NORTHEAST AND WEST WINDS
FOR MUCH OF TUESDAY WITH WEST WINDS WEST OF THERE AND NORTHEAST
WINDS NORTH AND EAST OF THERE. THE SNOWFALL AND CIGS WILL DECREASE
AND LIFT RESPECTIVELY FROM NORTHWEST TO SOUTHEAST DURING THE DAY
TUESDAY.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...LIPSON
FIRE WEATHER...BRANHAM











000
FXUS65 KRIW 021749
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
236 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
AN EXPANSIVE AREA OF SNOWFALL WILL PERSIST ACROSS THE EAST HALF OF
SWEETWATER COUNTY THROUGH 00Z TODAY RESULTING IN WIDESPREAD IFR/MVFR
CONDITIONS AND MTN OBSCURATIONS. VFR CONDITIONS...FL SCT-BKN200-250
WILL CONTINUE NORTH AND WEST OF THERE THROUGH 21Z THIS AFTERNOON.
A LOW PRESSURE SYSTEM LIFTING NE ACROSS THE GREAT BASIN WILL PUSH
SCT MVFR -SHRASN NORTH TO A VCNTY KLND-KCPR LINE 21Z TODAY-00Z TUE.
CONDITIONS WILL THEN DETERIORATE RAPIDLY AFTER 00Z TUE AS A COLD
FRONT PUSHES DOWN FROM THE NORTH BRINGING WIDESPREAD MVFR/IFR -SN
AND MTN OBSCURATIONS ACROSS THE AREA BY 4Z TUE ALONG WITH INCREASING
NORTH WIND AND SOME BLOWING SNOW.  THE HEAVIEST SNOWFALL AND AREAS OF
LIFR CONDITIONS WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE AS
THE SNOWFALL AND LOW CIGS ALREADY IN PLACE ACROSS THE EAST HALF OF
SWEETWATER COUNTY CONTINUE TO INCREASE AND LOWER RESPECTIVELY. THESE
CONDITIONS WILL PERSIST THROUGH 12Z TUE. THESE CONDITIONS WILL BEGIN
TO IMPROVE FROM NORTHWEST TO SOUTHEAST AFTER 12Z TUESDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
THE UPPER LEVEL DISTURBANCE BRINGING AN INITIAL BAND OF MVFR/IFR -SN
NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 WILL
IMPROVEMENT SOMEWHAT BY 19Z THIS AFTERNOON. THEN MORE WIDESPREAD
PERSISTENT IFR SNOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING
AROUND 20Z TODAY AND PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN
COLD FRONT PUSHING DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG
THE DIVIDE THIS EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD
MVFR/IFR -SN BY 06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.
KRKS WILL BE IN THE BATTLE ZONE BETWEEN THE NORTHEAST AND WEST WINDS
FOR MUCH OF TUESDAY WITH WEST WINDS WEST OF THERE AND NORTHEAST
WINDS NORTH AND EAST OF THERE. THE SNOWFALL AND CIGS WILL DECREASE
AND LIFT RESPECTIVELY FROM NORTHWEST TO SOUTHEAST DURING THE DAY
TUESDAY.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...LIPSON
FIRE WEATHER...BRANHAM











000
FXUS65 KRIW 021749
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
236 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
AN EXPANSIVE AREA OF SNOWFALL WILL PERSIST ACROSS THE EAST HALF OF
SWEETWATER COUNTY THROUGH 00Z TODAY RESULTING IN WIDESPREAD IFR/MVFR
CONDITIONS AND MTN OBSCURATIONS. VFR CONDITIONS...FL SCT-BKN200-250
WILL CONTINUE NORTH AND WEST OF THERE THROUGH 21Z THIS AFTERNOON.
A LOW PRESSURE SYSTEM LIFTING NE ACROSS THE GREAT BASIN WILL PUSH
SCT MVFR -SHRASN NORTH TO A VCNTY KLND-KCPR LINE 21Z TODAY-00Z TUE.
CONDITIONS WILL THEN DETERIORATE RAPIDLY AFTER 00Z TUE AS A COLD
FRONT PUSHES DOWN FROM THE NORTH BRINGING WIDESPREAD MVFR/IFR -SN
AND MTN OBSCURATIONS ACROSS THE AREA BY 4Z TUE ALONG WITH INCREASING
NORTH WIND AND SOME BLOWING SNOW.  THE HEAVIEST SNOWFALL AND AREAS OF
LIFR CONDITIONS WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE AS
THE SNOWFALL AND LOW CIGS ALREADY IN PLACE ACROSS THE EAST HALF OF
SWEETWATER COUNTY CONTINUE TO INCREASE AND LOWER RESPECTIVELY. THESE
CONDITIONS WILL PERSIST THROUGH 12Z TUE. THESE CONDITIONS WILL BEGIN
TO IMPROVE FROM NORTHWEST TO SOUTHEAST AFTER 12Z TUESDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
THE UPPER LEVEL DISTURBANCE BRINGING AN INITIAL BAND OF MVFR/IFR -SN
NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 WILL
IMPROVEMENT SOMEWHAT BY 19Z THIS AFTERNOON. THEN MORE WIDESPREAD
PERSISTENT IFR SNOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING
AROUND 20Z TODAY AND PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN
COLD FRONT PUSHING DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG
THE DIVIDE THIS EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD
MVFR/IFR -SN BY 06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.
KRKS WILL BE IN THE BATTLE ZONE BETWEEN THE NORTHEAST AND WEST WINDS
FOR MUCH OF TUESDAY WITH WEST WINDS WEST OF THERE AND NORTHEAST
WINDS NORTH AND EAST OF THERE. THE SNOWFALL AND CIGS WILL DECREASE
AND LIFT RESPECTIVELY FROM NORTHWEST TO SOUTHEAST DURING THE DAY
TUESDAY.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...LIPSON
FIRE WEATHER...BRANHAM











000
FXUS65 KRIW 021749
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
236 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
AN EXPANSIVE AREA OF SNOWFALL WILL PERSIST ACROSS THE EAST HALF OF
SWEETWATER COUNTY THROUGH 00Z TODAY RESULTING IN WIDESPREAD IFR/MVFR
CONDITIONS AND MTN OBSCURATIONS. VFR CONDITIONS...FL SCT-BKN200-250
WILL CONTINUE NORTH AND WEST OF THERE THROUGH 21Z THIS AFTERNOON.
A LOW PRESSURE SYSTEM LIFTING NE ACROSS THE GREAT BASIN WILL PUSH
SCT MVFR -SHRASN NORTH TO A VCNTY KLND-KCPR LINE 21Z TODAY-00Z TUE.
CONDITIONS WILL THEN DETERIORATE RAPIDLY AFTER 00Z TUE AS A COLD
FRONT PUSHES DOWN FROM THE NORTH BRINGING WIDESPREAD MVFR/IFR -SN
AND MTN OBSCURATIONS ACROSS THE AREA BY 4Z TUE ALONG WITH INCREASING
NORTH WIND AND SOME BLOWING SNOW.  THE HEAVIEST SNOWFALL AND AREAS OF
LIFR CONDITIONS WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE AS
THE SNOWFALL AND LOW CIGS ALREADY IN PLACE ACROSS THE EAST HALF OF
SWEETWATER COUNTY CONTINUE TO INCREASE AND LOWER RESPECTIVELY. THESE
CONDITIONS WILL PERSIST THROUGH 12Z TUE. THESE CONDITIONS WILL BEGIN
TO IMPROVE FROM NORTHWEST TO SOUTHEAST AFTER 12Z TUESDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
THE UPPER LEVEL DISTURBANCE BRINGING AN INITIAL BAND OF MVFR/IFR -SN
NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 WILL
IMPROVEMENT SOMEWHAT BY 19Z THIS AFTERNOON. THEN MORE WIDESPREAD
PERSISTENT IFR SNOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING
AROUND 20Z TODAY AND PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN
COLD FRONT PUSHING DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG
THE DIVIDE THIS EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD
MVFR/IFR -SN BY 06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.
KRKS WILL BE IN THE BATTLE ZONE BETWEEN THE NORTHEAST AND WEST WINDS
FOR MUCH OF TUESDAY WITH WEST WINDS WEST OF THERE AND NORTHEAST
WINDS NORTH AND EAST OF THERE. THE SNOWFALL AND CIGS WILL DECREASE
AND LIFT RESPECTIVELY FROM NORTHWEST TO SOUTHEAST DURING THE DAY
TUESDAY.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...LIPSON
FIRE WEATHER...BRANHAM











000
FXUS65 KRIW 021749
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
236 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../18Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
AN EXPANSIVE AREA OF SNOWFALL WILL PERSIST ACROSS THE EAST HALF OF
SWEETWATER COUNTY THROUGH 00Z TODAY RESULTING IN WIDESPREAD IFR/MVFR
CONDITIONS AND MTN OBSCURATIONS. VFR CONDITIONS...FL SCT-BKN200-250
WILL CONTINUE NORTH AND WEST OF THERE THROUGH 21Z THIS AFTERNOON.
A LOW PRESSURE SYSTEM LIFTING NE ACROSS THE GREAT BASIN WILL PUSH
SCT MVFR -SHRASN NORTH TO A VCNTY KLND-KCPR LINE 21Z TODAY-00Z TUE.
CONDITIONS WILL THEN DETERIORATE RAPIDLY AFTER 00Z TUE AS A COLD
FRONT PUSHES DOWN FROM THE NORTH BRINGING WIDESPREAD MVFR/IFR -SN
AND MTN OBSCURATIONS ACROSS THE AREA BY 4Z TUE ALONG WITH INCREASING
NORTH WIND AND SOME BLOWING SNOW.  THE HEAVIEST SNOWFALL AND AREAS OF
LIFR CONDITIONS WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE AS
THE SNOWFALL AND LOW CIGS ALREADY IN PLACE ACROSS THE EAST HALF OF
SWEETWATER COUNTY CONTINUE TO INCREASE AND LOWER RESPECTIVELY. THESE
CONDITIONS WILL PERSIST THROUGH 12Z TUE. THESE CONDITIONS WILL BEGIN
TO IMPROVE FROM NORTHWEST TO SOUTHEAST AFTER 12Z TUESDAY.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
THE UPPER LEVEL DISTURBANCE BRINGING AN INITIAL BAND OF MVFR/IFR -SN
NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 WILL
IMPROVEMENT SOMEWHAT BY 19Z THIS AFTERNOON. THEN MORE WIDESPREAD
PERSISTENT IFR SNOW IS EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING
AROUND 20Z TODAY AND PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN
COLD FRONT PUSHING DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG
THE DIVIDE THIS EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD
MVFR/IFR -SN BY 06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.
KRKS WILL BE IN THE BATTLE ZONE BETWEEN THE NORTHEAST AND WEST WINDS
FOR MUCH OF TUESDAY WITH WEST WINDS WEST OF THERE AND NORTHEAST
WINDS NORTH AND EAST OF THERE. THE SNOWFALL AND CIGS WILL DECREASE
AND LIFT RESPECTIVELY FROM NORTHWEST TO SOUTHEAST DURING THE DAY
TUESDAY.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...LIPSON
FIRE WEATHER...BRANHAM











000
FXUS65 KCYS 021732
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1031 AM MST MON MAR 2 2015

.UPDATE...
ISSUED AT 929 AM MST MON MAR 2 2015

STARTED THE WINTER STORM WARNING FOR ALL OF CARBON COUNTY
EFFECTIVE IMMEDIATELY. SNOW IS ALREADY ACCUMULATING ON THE ROAD
SURFACES ACROSS MUCH OF THE COUNTY WITH 1 TO 2 INCHES OF SNOW ALREADY
ON THE GROUND IN RAWLINS. LATEST GFS SHOWING HIGH SNOW FALL RATES
AND BASED ON MOSAIC RADAR OVER WESTERN COLORADO...THERE IS NOT
MUCH DOUBT SNOW WILL CONTINUE TO INTENSIFY THIS MORNING WITH SNOW
HEAVY AT TIMES THROUGH THIS AFTERNOON. THE REST OF THE WINTER
STORM PRODUCTS LOOK FINE. SOME LIGHT SNOW ACCUMULATIONS WILL
OCCUR AROUND LARAMIE BUT NOT MAIN PRECIPITATION AREA WILL SHIFT
SLIGHTLY WEST THIS AFTERNOON BEFORE SPREADING EAST TONIGHT WITH
THE MAIN UPPER LEVEL FEATURE.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 430 AM MST MON MAR 2 2015

A BUSY FORECAST PERIOD CONTINUES WITH A MAJOR WINTER STORM STILL
ON TRACK FOR MUCH OF THE CWA. MAIN CHALLENGES REVOLVE AROUND THE
TIMING/PLACEMENT OF HEAVIEST SNOWFALL AND WHAT IMPACTS THIS WILL
HAVE TO TRAVEL. DANGEROUS WIND CHILLS WILL UNDOUBTEDLY BECOME AN
ISSUE BY TUE NIGHT AND WED...AND TEMPERATURES WILL HINGE ON CLOUD
COVER AND SNOW DEPTHS HEADING INTO MIDWEEK. MORNING WV SAT IMAGERY
SHOWS DEEP TROUGHING OVER THE WESTERN CONUS. A SEPARATE AND MORE
VIGOROUS PIECE OF ENERGY WAS LOCATED OVER SOUTHERN CAL WITH THE
MUCH ANTICIPATED KICKER SYSTEM DIVING SOUTH ALONG THE WESTERN US
COASTLINE. EXCELLENT MOISTURE FETCH WAS OBSERVED DOWNSTREAM OVER
THE FOUR CORNERS...AS WELL AS GOOD INSTABILITY WITH A FEW RECENT
LIGHTNING STRIKES OVER CA/NV BENEATH THE UPPER LOW. THAT SAID...
CONFIDENCE IS HIGH FOR A HEAVY SNOWFALL EVENT IN OUR CWA.

WE DECIDED TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE
REST OF CARBON COUNTY...KEEPING START/END TIMES THE SAME. WE HAVE
SEEN SOLID RUN-TO-RUN AND MODEL-TO-MODEL CONSISTENCY AMONG BOTH
AMERICAN AND EUROPEAN GUIDANCE OVER THE LAST DAY OR SO. CONSENSUS
IS FOR THE SOUTHERN WAVE TO LIFT NORTHEAST INTO WESTERN CO BY THIS
AFTN WITH AN IMPRESSIVE 160+ KT H25 JET NOSING INTO SOUTHEAST WY
BY 00Z TUE. THIS PLACES OUR WESTERN ZONES IN THE FAVORED LEFT EXIT
REGION FOR A FEW HOURS THIS AFTERNOON...SO A PERIOD OF HEAVY SNOW
BANDING IS LIKELY WITH A SURFACE WARM FRONTAL BOUNDARY ORIENTED
FROM SW TO NE ACROSS THE CWA. NAM AND GFS MUCAPES BETWEEN 100 AND
200 J/KG SUGGESTS SOME CONVECTIVE ELEMENTS...SO RATES COULD EXCEED
AN INCH PER HOUR AT TIMES. SNOWIES AND SIERRA MADRES ARE STILL IN
GOOD SHAPE FOR AROUND 2 FEET OF TOTAL ACCUMULATIONS.

THE MORE WIDESPREAD EVENT HOLDS OFF UNTIL LATER THIS EVENING AND
OVERNIGHT WITH THE COLD FROPA. GFS/NAM/ECMWF ARE ALL IN EXCELLENT
AGREEMENT WITH THE ARCTIC FRONT SURGING SOUTH BETWEEN 06Z AND 12Z
TUE. SIGNIFICANT LLVL COLD ADVECTION SHOULD OCCUR WITH GFS 700 MB
TEMPS OVER CYS FALLING FROM +1C AT 00Z TO -13C AT 12Z TUE. FRONTAL
PASSAGE WILL RESULT IN ENHANCED LLVL CONVERGENCE AND FRONTOGENESIS
ALONG THE LARAMIE RANGE...AND UPSLOPE FLOW MOST PRONOUNCED OVER
THE NORTHERN MOUNTAINS. LATEST RUNS HAVE BEEN HITTING THE NORTH
LARAMIE RANGE HARD WITH AN AVERAGE OF AROUND 0.7 INCH QPF...WHICH
IS NOT SURPRISING WITH STEEPENING LAPSE RATES ALOFT. BEST SUPPORT
WILL BE FAST MOVING...BUT RATES SHOULD BE HIGH ENOUGH TO GET CLOSE
TO A FOOT OF SNOW OVER NORTH FACING SLOPES. WINDS SHOULD COME INTO
PLAY AS WELL AS COLD ADVECTION YIELDS STRONG MIXING OVERNIGHT WITH
30 TO 40 KTS AVAILABLE TO MIX. WENT AHEAD AND ADDED THE NORTHERN
LARAMIE RANGE AND LOWER ELEVATIONS OF CONVERSE TO THE WARNING EVEN
THOUGH AMOUNTS COULD BE MARGINAL.

A BAND OF SNOW SHOULD EXTEND FARTHER EAST ONTO THE PLAINS TOWARD
THE WESTERN NEBRASKA PANHANDLE. MOST LIKELY AREA FOR THIS TO OCCUR
IS ACROSS THE NORTHERN ZONES WITH THE INITIAL FRONTAL SURGE. BIG
QUESTIONS FOR THE INTERSTATE 80 CORRIDOR AS H7-H3 RH PROGS SHOW A
SUBSTANTIAL DRY SLOT SNEAKING INTO OUR EXTREME SOUTHEAST CWA. WE
BELIEVE LIGHT ACCUMULATIONS AND INCREASING WINDS TONIGHT WILL BE
ENOUGH TO CAUSE SIGNIFICANT TRAVEL DIFFICULTY...ESPECIALLY ALONG
INTERSTATE 80. DECIDED ON A WINTER WEATHER ADVISORY FROM THE SOUTH
LARAMIE RANGE NORTHEAST INTO THE NORTHERN PANHANDLE. SNOW SHOULD
SLOWLY END ON TUE NIGHT AND WED AS THE SYSTEM DEPARTS...BUT A FEW
SHOWERS WILL PERSIST AS A SECONDARY SHORTWAVE SWINGS AROUND THE
BACK SIDE OF THE LARGER SCALE TROUGH. DESPITE PLENTY OF CLOUDS
PREVENTING MAJOR RADIATIONAL COOLING...H7 TEMPS AS COLD AS -20 C
AT 12Z WED SUGGESTS SUB ZERO READINGS. EXPECT THAT SOME SORT OF
WIND CHILL HEADLINES WILL BE NECESSARY ON THE HEELS OF ONGOING
WINTER WEATHER PRODUCTS. KEPT HIGHS BELOW GUIDANCE FOR BOTH TUE
AND WED WITH WIDESPREAD SNOW AND COLD ADVECTION ALOFT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 AM MST MON MAR 2 2015

00Z MODELS INDICATE NORTHWEST FLOW ALOFT BEHIND EXITING TROUGH
AND UPPER RIDGE EXPANDING EAST TOWARD THE GREAT BASIN. A WEAK
SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE CWA THURSDAY MORNING
WITH LITTLE OR NO ASSOCIATED MOISTURE. 700MB WINDS INCREASE TO
50 KT ALONG THE I-80 CORRIDOR BETWEEN ARLINGTON AND CHEYENNE
WEDNESDAY NIGHT/THURSDAY MORNING. OVER THE NORTH SNOWY RANGE
FOOTHILLS/CENTRAL LARAMIE RANGE. THE CENTER OF UPPER RIDGE MOVES
INTO CA/NV FRIDAY WITH LIGHTER NORTHWEST FLOW. THERE ARE MODEL
DIFFERENCES THIS WEEKEND AS THE ECMWF SHOWS A POTENT SHORTWAVE
TROUGH TRACKING SOUTHEAST FROM ID/WESTERN MT ACROSS WY/CO
SATURDAY...PRODUCING LIGHT PRECIPITATION. THE GFS DOES NOT SHOW
THIS FEATURE BUT AMPLIFIES THE NORTHWEST FLOW ALOFT AS SHORTWAVE
ENERGY MOVES ACROSS THE NORTHERN U.S. FOR NOW...LEFT POPS BELOW
15 PERCENT BUT THEY MAY BE INCREASED LATER IF THE GFS TRENDS
TOWARD THE ECMWF. A COLD FRONT WILL MOVE THROUGH THE REGION
SATURDAY. IT DOES NOT LOOK AS COLD BEHIND THE FRONT COMPARED TO
EARLIER MODEL RUNS. HIGHS THURSDAY WILL BE ABOUT 20 DEGREES WARMER
THAN WEDNESDAY AS DOWNSLOPE WEST-NORTHWEST WINDS DEVELOP LEE OF
LARAMIE RANGE. TEMPERATURES FINALLY WARM TO NEAR SEASONAL NORMALS
FRIDAY WITH HIGHS IN THE 30S AND 40S. IT WILL BE A TAD COOLER FOR
THE PLAINS SATURDAY. UPPER RIDGE BUILDS CLOSER WITH DOWNSLOPE
NORTHWEST FLOW KEEPING TEMPERATURES SEASONABLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1031 AM MST MON MAR 2 2015

LIFR CONDS WITH SNOW AND LOW CIGS LIKELY THROUGH THE PD AFFECTING
THE KRWL AREA WHILE ELSEWHERE SCTD MVFR CIGS EXPECTED THROUGH THIS
EVENING.  SFC COLD FRONT WILL MOVE SOUTH ACROSS THE AREA LATE THIS
EVENING AND OVERNIGHT WITH MAINLY IFR CONDITIONS BECOMING WIDESPREAD
LATER TONIGHT INTO TUESDAY MORNING.

&&

.FIRE WEATHER...
ISSUED AT 430 AM MST MON MAR 2 2015

NO FIRE WEATHER CONCERNS. SNOW IS EXPECTED TO DEVELOP TODAY AND
BECOME WIDESPREAD TONIGHT AND TUESDAY. SIGNIFICANT ACCUMULATIONS
ARE POSSIBLE...ESPECIALLY IN THE MOUNTAINS AND LOWER ELEVATION
AREAS WEST OF THE LARAMIE RANGE. THE SNOW WILL GRADUALLY DIMINISH
BY TUESDAY NIGHT. AN ARCTIC COLD FRONT WILL BRING BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS FROM TUESDAY NIGHT THROUGH
WEDNESDAY. MODERATING TEMPERATURES ARE EXPECTED LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR WYZ102-106>108-115>117.

     WINTER STORM WARNING UNTIL 6 PM MST TUESDAY FOR WYZ104-105-
     109>114.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 PM MST
     TUESDAY FOR WYZ101-103.

NE...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR NEZ002-003-095-096.

&&

$$

UPDATE...SML
SHORT TERM...CLH
LONG TERM...MJ
AVIATION...RE
FIRE WEATHER...CLH




000
FXUS65 KCYS 021732
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1031 AM MST MON MAR 2 2015

.UPDATE...
ISSUED AT 929 AM MST MON MAR 2 2015

STARTED THE WINTER STORM WARNING FOR ALL OF CARBON COUNTY
EFFECTIVE IMMEDIATELY. SNOW IS ALREADY ACCUMULATING ON THE ROAD
SURFACES ACROSS MUCH OF THE COUNTY WITH 1 TO 2 INCHES OF SNOW ALREADY
ON THE GROUND IN RAWLINS. LATEST GFS SHOWING HIGH SNOW FALL RATES
AND BASED ON MOSAIC RADAR OVER WESTERN COLORADO...THERE IS NOT
MUCH DOUBT SNOW WILL CONTINUE TO INTENSIFY THIS MORNING WITH SNOW
HEAVY AT TIMES THROUGH THIS AFTERNOON. THE REST OF THE WINTER
STORM PRODUCTS LOOK FINE. SOME LIGHT SNOW ACCUMULATIONS WILL
OCCUR AROUND LARAMIE BUT NOT MAIN PRECIPITATION AREA WILL SHIFT
SLIGHTLY WEST THIS AFTERNOON BEFORE SPREADING EAST TONIGHT WITH
THE MAIN UPPER LEVEL FEATURE.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 430 AM MST MON MAR 2 2015

A BUSY FORECAST PERIOD CONTINUES WITH A MAJOR WINTER STORM STILL
ON TRACK FOR MUCH OF THE CWA. MAIN CHALLENGES REVOLVE AROUND THE
TIMING/PLACEMENT OF HEAVIEST SNOWFALL AND WHAT IMPACTS THIS WILL
HAVE TO TRAVEL. DANGEROUS WIND CHILLS WILL UNDOUBTEDLY BECOME AN
ISSUE BY TUE NIGHT AND WED...AND TEMPERATURES WILL HINGE ON CLOUD
COVER AND SNOW DEPTHS HEADING INTO MIDWEEK. MORNING WV SAT IMAGERY
SHOWS DEEP TROUGHING OVER THE WESTERN CONUS. A SEPARATE AND MORE
VIGOROUS PIECE OF ENERGY WAS LOCATED OVER SOUTHERN CAL WITH THE
MUCH ANTICIPATED KICKER SYSTEM DIVING SOUTH ALONG THE WESTERN US
COASTLINE. EXCELLENT MOISTURE FETCH WAS OBSERVED DOWNSTREAM OVER
THE FOUR CORNERS...AS WELL AS GOOD INSTABILITY WITH A FEW RECENT
LIGHTNING STRIKES OVER CA/NV BENEATH THE UPPER LOW. THAT SAID...
CONFIDENCE IS HIGH FOR A HEAVY SNOWFALL EVENT IN OUR CWA.

WE DECIDED TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE
REST OF CARBON COUNTY...KEEPING START/END TIMES THE SAME. WE HAVE
SEEN SOLID RUN-TO-RUN AND MODEL-TO-MODEL CONSISTENCY AMONG BOTH
AMERICAN AND EUROPEAN GUIDANCE OVER THE LAST DAY OR SO. CONSENSUS
IS FOR THE SOUTHERN WAVE TO LIFT NORTHEAST INTO WESTERN CO BY THIS
AFTN WITH AN IMPRESSIVE 160+ KT H25 JET NOSING INTO SOUTHEAST WY
BY 00Z TUE. THIS PLACES OUR WESTERN ZONES IN THE FAVORED LEFT EXIT
REGION FOR A FEW HOURS THIS AFTERNOON...SO A PERIOD OF HEAVY SNOW
BANDING IS LIKELY WITH A SURFACE WARM FRONTAL BOUNDARY ORIENTED
FROM SW TO NE ACROSS THE CWA. NAM AND GFS MUCAPES BETWEEN 100 AND
200 J/KG SUGGESTS SOME CONVECTIVE ELEMENTS...SO RATES COULD EXCEED
AN INCH PER HOUR AT TIMES. SNOWIES AND SIERRA MADRES ARE STILL IN
GOOD SHAPE FOR AROUND 2 FEET OF TOTAL ACCUMULATIONS.

THE MORE WIDESPREAD EVENT HOLDS OFF UNTIL LATER THIS EVENING AND
OVERNIGHT WITH THE COLD FROPA. GFS/NAM/ECMWF ARE ALL IN EXCELLENT
AGREEMENT WITH THE ARCTIC FRONT SURGING SOUTH BETWEEN 06Z AND 12Z
TUE. SIGNIFICANT LLVL COLD ADVECTION SHOULD OCCUR WITH GFS 700 MB
TEMPS OVER CYS FALLING FROM +1C AT 00Z TO -13C AT 12Z TUE. FRONTAL
PASSAGE WILL RESULT IN ENHANCED LLVL CONVERGENCE AND FRONTOGENESIS
ALONG THE LARAMIE RANGE...AND UPSLOPE FLOW MOST PRONOUNCED OVER
THE NORTHERN MOUNTAINS. LATEST RUNS HAVE BEEN HITTING THE NORTH
LARAMIE RANGE HARD WITH AN AVERAGE OF AROUND 0.7 INCH QPF...WHICH
IS NOT SURPRISING WITH STEEPENING LAPSE RATES ALOFT. BEST SUPPORT
WILL BE FAST MOVING...BUT RATES SHOULD BE HIGH ENOUGH TO GET CLOSE
TO A FOOT OF SNOW OVER NORTH FACING SLOPES. WINDS SHOULD COME INTO
PLAY AS WELL AS COLD ADVECTION YIELDS STRONG MIXING OVERNIGHT WITH
30 TO 40 KTS AVAILABLE TO MIX. WENT AHEAD AND ADDED THE NORTHERN
LARAMIE RANGE AND LOWER ELEVATIONS OF CONVERSE TO THE WARNING EVEN
THOUGH AMOUNTS COULD BE MARGINAL.

A BAND OF SNOW SHOULD EXTEND FARTHER EAST ONTO THE PLAINS TOWARD
THE WESTERN NEBRASKA PANHANDLE. MOST LIKELY AREA FOR THIS TO OCCUR
IS ACROSS THE NORTHERN ZONES WITH THE INITIAL FRONTAL SURGE. BIG
QUESTIONS FOR THE INTERSTATE 80 CORRIDOR AS H7-H3 RH PROGS SHOW A
SUBSTANTIAL DRY SLOT SNEAKING INTO OUR EXTREME SOUTHEAST CWA. WE
BELIEVE LIGHT ACCUMULATIONS AND INCREASING WINDS TONIGHT WILL BE
ENOUGH TO CAUSE SIGNIFICANT TRAVEL DIFFICULTY...ESPECIALLY ALONG
INTERSTATE 80. DECIDED ON A WINTER WEATHER ADVISORY FROM THE SOUTH
LARAMIE RANGE NORTHEAST INTO THE NORTHERN PANHANDLE. SNOW SHOULD
SLOWLY END ON TUE NIGHT AND WED AS THE SYSTEM DEPARTS...BUT A FEW
SHOWERS WILL PERSIST AS A SECONDARY SHORTWAVE SWINGS AROUND THE
BACK SIDE OF THE LARGER SCALE TROUGH. DESPITE PLENTY OF CLOUDS
PREVENTING MAJOR RADIATIONAL COOLING...H7 TEMPS AS COLD AS -20 C
AT 12Z WED SUGGESTS SUB ZERO READINGS. EXPECT THAT SOME SORT OF
WIND CHILL HEADLINES WILL BE NECESSARY ON THE HEELS OF ONGOING
WINTER WEATHER PRODUCTS. KEPT HIGHS BELOW GUIDANCE FOR BOTH TUE
AND WED WITH WIDESPREAD SNOW AND COLD ADVECTION ALOFT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 AM MST MON MAR 2 2015

00Z MODELS INDICATE NORTHWEST FLOW ALOFT BEHIND EXITING TROUGH
AND UPPER RIDGE EXPANDING EAST TOWARD THE GREAT BASIN. A WEAK
SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE CWA THURSDAY MORNING
WITH LITTLE OR NO ASSOCIATED MOISTURE. 700MB WINDS INCREASE TO
50 KT ALONG THE I-80 CORRIDOR BETWEEN ARLINGTON AND CHEYENNE
WEDNESDAY NIGHT/THURSDAY MORNING. OVER THE NORTH SNOWY RANGE
FOOTHILLS/CENTRAL LARAMIE RANGE. THE CENTER OF UPPER RIDGE MOVES
INTO CA/NV FRIDAY WITH LIGHTER NORTHWEST FLOW. THERE ARE MODEL
DIFFERENCES THIS WEEKEND AS THE ECMWF SHOWS A POTENT SHORTWAVE
TROUGH TRACKING SOUTHEAST FROM ID/WESTERN MT ACROSS WY/CO
SATURDAY...PRODUCING LIGHT PRECIPITATION. THE GFS DOES NOT SHOW
THIS FEATURE BUT AMPLIFIES THE NORTHWEST FLOW ALOFT AS SHORTWAVE
ENERGY MOVES ACROSS THE NORTHERN U.S. FOR NOW...LEFT POPS BELOW
15 PERCENT BUT THEY MAY BE INCREASED LATER IF THE GFS TRENDS
TOWARD THE ECMWF. A COLD FRONT WILL MOVE THROUGH THE REGION
SATURDAY. IT DOES NOT LOOK AS COLD BEHIND THE FRONT COMPARED TO
EARLIER MODEL RUNS. HIGHS THURSDAY WILL BE ABOUT 20 DEGREES WARMER
THAN WEDNESDAY AS DOWNSLOPE WEST-NORTHWEST WINDS DEVELOP LEE OF
LARAMIE RANGE. TEMPERATURES FINALLY WARM TO NEAR SEASONAL NORMALS
FRIDAY WITH HIGHS IN THE 30S AND 40S. IT WILL BE A TAD COOLER FOR
THE PLAINS SATURDAY. UPPER RIDGE BUILDS CLOSER WITH DOWNSLOPE
NORTHWEST FLOW KEEPING TEMPERATURES SEASONABLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1031 AM MST MON MAR 2 2015

LIFR CONDS WITH SNOW AND LOW CIGS LIKELY THROUGH THE PD AFFECTING
THE KRWL AREA WHILE ELSEWHERE SCTD MVFR CIGS EXPECTED THROUGH THIS
EVENING.  SFC COLD FRONT WILL MOVE SOUTH ACROSS THE AREA LATE THIS
EVENING AND OVERNIGHT WITH MAINLY IFR CONDITIONS BECOMING WIDESPREAD
LATER TONIGHT INTO TUESDAY MORNING.

&&

.FIRE WEATHER...
ISSUED AT 430 AM MST MON MAR 2 2015

NO FIRE WEATHER CONCERNS. SNOW IS EXPECTED TO DEVELOP TODAY AND
BECOME WIDESPREAD TONIGHT AND TUESDAY. SIGNIFICANT ACCUMULATIONS
ARE POSSIBLE...ESPECIALLY IN THE MOUNTAINS AND LOWER ELEVATION
AREAS WEST OF THE LARAMIE RANGE. THE SNOW WILL GRADUALLY DIMINISH
BY TUESDAY NIGHT. AN ARCTIC COLD FRONT WILL BRING BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS FROM TUESDAY NIGHT THROUGH
WEDNESDAY. MODERATING TEMPERATURES ARE EXPECTED LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR WYZ102-106>108-115>117.

     WINTER STORM WARNING UNTIL 6 PM MST TUESDAY FOR WYZ104-105-
     109>114.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 PM MST
     TUESDAY FOR WYZ101-103.

NE...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR NEZ002-003-095-096.

&&

$$

UPDATE...SML
SHORT TERM...CLH
LONG TERM...MJ
AVIATION...RE
FIRE WEATHER...CLH



000
FXUS65 KCYS 021732
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1031 AM MST MON MAR 2 2015

.UPDATE...
ISSUED AT 929 AM MST MON MAR 2 2015

STARTED THE WINTER STORM WARNING FOR ALL OF CARBON COUNTY
EFFECTIVE IMMEDIATELY. SNOW IS ALREADY ACCUMULATING ON THE ROAD
SURFACES ACROSS MUCH OF THE COUNTY WITH 1 TO 2 INCHES OF SNOW ALREADY
ON THE GROUND IN RAWLINS. LATEST GFS SHOWING HIGH SNOW FALL RATES
AND BASED ON MOSAIC RADAR OVER WESTERN COLORADO...THERE IS NOT
MUCH DOUBT SNOW WILL CONTINUE TO INTENSIFY THIS MORNING WITH SNOW
HEAVY AT TIMES THROUGH THIS AFTERNOON. THE REST OF THE WINTER
STORM PRODUCTS LOOK FINE. SOME LIGHT SNOW ACCUMULATIONS WILL
OCCUR AROUND LARAMIE BUT NOT MAIN PRECIPITATION AREA WILL SHIFT
SLIGHTLY WEST THIS AFTERNOON BEFORE SPREADING EAST TONIGHT WITH
THE MAIN UPPER LEVEL FEATURE.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 430 AM MST MON MAR 2 2015

A BUSY FORECAST PERIOD CONTINUES WITH A MAJOR WINTER STORM STILL
ON TRACK FOR MUCH OF THE CWA. MAIN CHALLENGES REVOLVE AROUND THE
TIMING/PLACEMENT OF HEAVIEST SNOWFALL AND WHAT IMPACTS THIS WILL
HAVE TO TRAVEL. DANGEROUS WIND CHILLS WILL UNDOUBTEDLY BECOME AN
ISSUE BY TUE NIGHT AND WED...AND TEMPERATURES WILL HINGE ON CLOUD
COVER AND SNOW DEPTHS HEADING INTO MIDWEEK. MORNING WV SAT IMAGERY
SHOWS DEEP TROUGHING OVER THE WESTERN CONUS. A SEPARATE AND MORE
VIGOROUS PIECE OF ENERGY WAS LOCATED OVER SOUTHERN CAL WITH THE
MUCH ANTICIPATED KICKER SYSTEM DIVING SOUTH ALONG THE WESTERN US
COASTLINE. EXCELLENT MOISTURE FETCH WAS OBSERVED DOWNSTREAM OVER
THE FOUR CORNERS...AS WELL AS GOOD INSTABILITY WITH A FEW RECENT
LIGHTNING STRIKES OVER CA/NV BENEATH THE UPPER LOW. THAT SAID...
CONFIDENCE IS HIGH FOR A HEAVY SNOWFALL EVENT IN OUR CWA.

WE DECIDED TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE
REST OF CARBON COUNTY...KEEPING START/END TIMES THE SAME. WE HAVE
SEEN SOLID RUN-TO-RUN AND MODEL-TO-MODEL CONSISTENCY AMONG BOTH
AMERICAN AND EUROPEAN GUIDANCE OVER THE LAST DAY OR SO. CONSENSUS
IS FOR THE SOUTHERN WAVE TO LIFT NORTHEAST INTO WESTERN CO BY THIS
AFTN WITH AN IMPRESSIVE 160+ KT H25 JET NOSING INTO SOUTHEAST WY
BY 00Z TUE. THIS PLACES OUR WESTERN ZONES IN THE FAVORED LEFT EXIT
REGION FOR A FEW HOURS THIS AFTERNOON...SO A PERIOD OF HEAVY SNOW
BANDING IS LIKELY WITH A SURFACE WARM FRONTAL BOUNDARY ORIENTED
FROM SW TO NE ACROSS THE CWA. NAM AND GFS MUCAPES BETWEEN 100 AND
200 J/KG SUGGESTS SOME CONVECTIVE ELEMENTS...SO RATES COULD EXCEED
AN INCH PER HOUR AT TIMES. SNOWIES AND SIERRA MADRES ARE STILL IN
GOOD SHAPE FOR AROUND 2 FEET OF TOTAL ACCUMULATIONS.

THE MORE WIDESPREAD EVENT HOLDS OFF UNTIL LATER THIS EVENING AND
OVERNIGHT WITH THE COLD FROPA. GFS/NAM/ECMWF ARE ALL IN EXCELLENT
AGREEMENT WITH THE ARCTIC FRONT SURGING SOUTH BETWEEN 06Z AND 12Z
TUE. SIGNIFICANT LLVL COLD ADVECTION SHOULD OCCUR WITH GFS 700 MB
TEMPS OVER CYS FALLING FROM +1C AT 00Z TO -13C AT 12Z TUE. FRONTAL
PASSAGE WILL RESULT IN ENHANCED LLVL CONVERGENCE AND FRONTOGENESIS
ALONG THE LARAMIE RANGE...AND UPSLOPE FLOW MOST PRONOUNCED OVER
THE NORTHERN MOUNTAINS. LATEST RUNS HAVE BEEN HITTING THE NORTH
LARAMIE RANGE HARD WITH AN AVERAGE OF AROUND 0.7 INCH QPF...WHICH
IS NOT SURPRISING WITH STEEPENING LAPSE RATES ALOFT. BEST SUPPORT
WILL BE FAST MOVING...BUT RATES SHOULD BE HIGH ENOUGH TO GET CLOSE
TO A FOOT OF SNOW OVER NORTH FACING SLOPES. WINDS SHOULD COME INTO
PLAY AS WELL AS COLD ADVECTION YIELDS STRONG MIXING OVERNIGHT WITH
30 TO 40 KTS AVAILABLE TO MIX. WENT AHEAD AND ADDED THE NORTHERN
LARAMIE RANGE AND LOWER ELEVATIONS OF CONVERSE TO THE WARNING EVEN
THOUGH AMOUNTS COULD BE MARGINAL.

A BAND OF SNOW SHOULD EXTEND FARTHER EAST ONTO THE PLAINS TOWARD
THE WESTERN NEBRASKA PANHANDLE. MOST LIKELY AREA FOR THIS TO OCCUR
IS ACROSS THE NORTHERN ZONES WITH THE INITIAL FRONTAL SURGE. BIG
QUESTIONS FOR THE INTERSTATE 80 CORRIDOR AS H7-H3 RH PROGS SHOW A
SUBSTANTIAL DRY SLOT SNEAKING INTO OUR EXTREME SOUTHEAST CWA. WE
BELIEVE LIGHT ACCUMULATIONS AND INCREASING WINDS TONIGHT WILL BE
ENOUGH TO CAUSE SIGNIFICANT TRAVEL DIFFICULTY...ESPECIALLY ALONG
INTERSTATE 80. DECIDED ON A WINTER WEATHER ADVISORY FROM THE SOUTH
LARAMIE RANGE NORTHEAST INTO THE NORTHERN PANHANDLE. SNOW SHOULD
SLOWLY END ON TUE NIGHT AND WED AS THE SYSTEM DEPARTS...BUT A FEW
SHOWERS WILL PERSIST AS A SECONDARY SHORTWAVE SWINGS AROUND THE
BACK SIDE OF THE LARGER SCALE TROUGH. DESPITE PLENTY OF CLOUDS
PREVENTING MAJOR RADIATIONAL COOLING...H7 TEMPS AS COLD AS -20 C
AT 12Z WED SUGGESTS SUB ZERO READINGS. EXPECT THAT SOME SORT OF
WIND CHILL HEADLINES WILL BE NECESSARY ON THE HEELS OF ONGOING
WINTER WEATHER PRODUCTS. KEPT HIGHS BELOW GUIDANCE FOR BOTH TUE
AND WED WITH WIDESPREAD SNOW AND COLD ADVECTION ALOFT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 AM MST MON MAR 2 2015

00Z MODELS INDICATE NORTHWEST FLOW ALOFT BEHIND EXITING TROUGH
AND UPPER RIDGE EXPANDING EAST TOWARD THE GREAT BASIN. A WEAK
SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE CWA THURSDAY MORNING
WITH LITTLE OR NO ASSOCIATED MOISTURE. 700MB WINDS INCREASE TO
50 KT ALONG THE I-80 CORRIDOR BETWEEN ARLINGTON AND CHEYENNE
WEDNESDAY NIGHT/THURSDAY MORNING. OVER THE NORTH SNOWY RANGE
FOOTHILLS/CENTRAL LARAMIE RANGE. THE CENTER OF UPPER RIDGE MOVES
INTO CA/NV FRIDAY WITH LIGHTER NORTHWEST FLOW. THERE ARE MODEL
DIFFERENCES THIS WEEKEND AS THE ECMWF SHOWS A POTENT SHORTWAVE
TROUGH TRACKING SOUTHEAST FROM ID/WESTERN MT ACROSS WY/CO
SATURDAY...PRODUCING LIGHT PRECIPITATION. THE GFS DOES NOT SHOW
THIS FEATURE BUT AMPLIFIES THE NORTHWEST FLOW ALOFT AS SHORTWAVE
ENERGY MOVES ACROSS THE NORTHERN U.S. FOR NOW...LEFT POPS BELOW
15 PERCENT BUT THEY MAY BE INCREASED LATER IF THE GFS TRENDS
TOWARD THE ECMWF. A COLD FRONT WILL MOVE THROUGH THE REGION
SATURDAY. IT DOES NOT LOOK AS COLD BEHIND THE FRONT COMPARED TO
EARLIER MODEL RUNS. HIGHS THURSDAY WILL BE ABOUT 20 DEGREES WARMER
THAN WEDNESDAY AS DOWNSLOPE WEST-NORTHWEST WINDS DEVELOP LEE OF
LARAMIE RANGE. TEMPERATURES FINALLY WARM TO NEAR SEASONAL NORMALS
FRIDAY WITH HIGHS IN THE 30S AND 40S. IT WILL BE A TAD COOLER FOR
THE PLAINS SATURDAY. UPPER RIDGE BUILDS CLOSER WITH DOWNSLOPE
NORTHWEST FLOW KEEPING TEMPERATURES SEASONABLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1031 AM MST MON MAR 2 2015

LIFR CONDS WITH SNOW AND LOW CIGS LIKELY THROUGH THE PD AFFECTING
THE KRWL AREA WHILE ELSEWHERE SCTD MVFR CIGS EXPECTED THROUGH THIS
EVENING.  SFC COLD FRONT WILL MOVE SOUTH ACROSS THE AREA LATE THIS
EVENING AND OVERNIGHT WITH MAINLY IFR CONDITIONS BECOMING WIDESPREAD
LATER TONIGHT INTO TUESDAY MORNING.

&&

.FIRE WEATHER...
ISSUED AT 430 AM MST MON MAR 2 2015

NO FIRE WEATHER CONCERNS. SNOW IS EXPECTED TO DEVELOP TODAY AND
BECOME WIDESPREAD TONIGHT AND TUESDAY. SIGNIFICANT ACCUMULATIONS
ARE POSSIBLE...ESPECIALLY IN THE MOUNTAINS AND LOWER ELEVATION
AREAS WEST OF THE LARAMIE RANGE. THE SNOW WILL GRADUALLY DIMINISH
BY TUESDAY NIGHT. AN ARCTIC COLD FRONT WILL BRING BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS FROM TUESDAY NIGHT THROUGH
WEDNESDAY. MODERATING TEMPERATURES ARE EXPECTED LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR WYZ102-106>108-115>117.

     WINTER STORM WARNING UNTIL 6 PM MST TUESDAY FOR WYZ104-105-
     109>114.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 PM MST
     TUESDAY FOR WYZ101-103.

NE...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR NEZ002-003-095-096.

&&

$$

UPDATE...SML
SHORT TERM...CLH
LONG TERM...MJ
AVIATION...RE
FIRE WEATHER...CLH



000
FXUS65 KCYS 021732
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1031 AM MST MON MAR 2 2015

.UPDATE...
ISSUED AT 929 AM MST MON MAR 2 2015

STARTED THE WINTER STORM WARNING FOR ALL OF CARBON COUNTY
EFFECTIVE IMMEDIATELY. SNOW IS ALREADY ACCUMULATING ON THE ROAD
SURFACES ACROSS MUCH OF THE COUNTY WITH 1 TO 2 INCHES OF SNOW ALREADY
ON THE GROUND IN RAWLINS. LATEST GFS SHOWING HIGH SNOW FALL RATES
AND BASED ON MOSAIC RADAR OVER WESTERN COLORADO...THERE IS NOT
MUCH DOUBT SNOW WILL CONTINUE TO INTENSIFY THIS MORNING WITH SNOW
HEAVY AT TIMES THROUGH THIS AFTERNOON. THE REST OF THE WINTER
STORM PRODUCTS LOOK FINE. SOME LIGHT SNOW ACCUMULATIONS WILL
OCCUR AROUND LARAMIE BUT NOT MAIN PRECIPITATION AREA WILL SHIFT
SLIGHTLY WEST THIS AFTERNOON BEFORE SPREADING EAST TONIGHT WITH
THE MAIN UPPER LEVEL FEATURE.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 430 AM MST MON MAR 2 2015

A BUSY FORECAST PERIOD CONTINUES WITH A MAJOR WINTER STORM STILL
ON TRACK FOR MUCH OF THE CWA. MAIN CHALLENGES REVOLVE AROUND THE
TIMING/PLACEMENT OF HEAVIEST SNOWFALL AND WHAT IMPACTS THIS WILL
HAVE TO TRAVEL. DANGEROUS WIND CHILLS WILL UNDOUBTEDLY BECOME AN
ISSUE BY TUE NIGHT AND WED...AND TEMPERATURES WILL HINGE ON CLOUD
COVER AND SNOW DEPTHS HEADING INTO MIDWEEK. MORNING WV SAT IMAGERY
SHOWS DEEP TROUGHING OVER THE WESTERN CONUS. A SEPARATE AND MORE
VIGOROUS PIECE OF ENERGY WAS LOCATED OVER SOUTHERN CAL WITH THE
MUCH ANTICIPATED KICKER SYSTEM DIVING SOUTH ALONG THE WESTERN US
COASTLINE. EXCELLENT MOISTURE FETCH WAS OBSERVED DOWNSTREAM OVER
THE FOUR CORNERS...AS WELL AS GOOD INSTABILITY WITH A FEW RECENT
LIGHTNING STRIKES OVER CA/NV BENEATH THE UPPER LOW. THAT SAID...
CONFIDENCE IS HIGH FOR A HEAVY SNOWFALL EVENT IN OUR CWA.

WE DECIDED TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE
REST OF CARBON COUNTY...KEEPING START/END TIMES THE SAME. WE HAVE
SEEN SOLID RUN-TO-RUN AND MODEL-TO-MODEL CONSISTENCY AMONG BOTH
AMERICAN AND EUROPEAN GUIDANCE OVER THE LAST DAY OR SO. CONSENSUS
IS FOR THE SOUTHERN WAVE TO LIFT NORTHEAST INTO WESTERN CO BY THIS
AFTN WITH AN IMPRESSIVE 160+ KT H25 JET NOSING INTO SOUTHEAST WY
BY 00Z TUE. THIS PLACES OUR WESTERN ZONES IN THE FAVORED LEFT EXIT
REGION FOR A FEW HOURS THIS AFTERNOON...SO A PERIOD OF HEAVY SNOW
BANDING IS LIKELY WITH A SURFACE WARM FRONTAL BOUNDARY ORIENTED
FROM SW TO NE ACROSS THE CWA. NAM AND GFS MUCAPES BETWEEN 100 AND
200 J/KG SUGGESTS SOME CONVECTIVE ELEMENTS...SO RATES COULD EXCEED
AN INCH PER HOUR AT TIMES. SNOWIES AND SIERRA MADRES ARE STILL IN
GOOD SHAPE FOR AROUND 2 FEET OF TOTAL ACCUMULATIONS.

THE MORE WIDESPREAD EVENT HOLDS OFF UNTIL LATER THIS EVENING AND
OVERNIGHT WITH THE COLD FROPA. GFS/NAM/ECMWF ARE ALL IN EXCELLENT
AGREEMENT WITH THE ARCTIC FRONT SURGING SOUTH BETWEEN 06Z AND 12Z
TUE. SIGNIFICANT LLVL COLD ADVECTION SHOULD OCCUR WITH GFS 700 MB
TEMPS OVER CYS FALLING FROM +1C AT 00Z TO -13C AT 12Z TUE. FRONTAL
PASSAGE WILL RESULT IN ENHANCED LLVL CONVERGENCE AND FRONTOGENESIS
ALONG THE LARAMIE RANGE...AND UPSLOPE FLOW MOST PRONOUNCED OVER
THE NORTHERN MOUNTAINS. LATEST RUNS HAVE BEEN HITTING THE NORTH
LARAMIE RANGE HARD WITH AN AVERAGE OF AROUND 0.7 INCH QPF...WHICH
IS NOT SURPRISING WITH STEEPENING LAPSE RATES ALOFT. BEST SUPPORT
WILL BE FAST MOVING...BUT RATES SHOULD BE HIGH ENOUGH TO GET CLOSE
TO A FOOT OF SNOW OVER NORTH FACING SLOPES. WINDS SHOULD COME INTO
PLAY AS WELL AS COLD ADVECTION YIELDS STRONG MIXING OVERNIGHT WITH
30 TO 40 KTS AVAILABLE TO MIX. WENT AHEAD AND ADDED THE NORTHERN
LARAMIE RANGE AND LOWER ELEVATIONS OF CONVERSE TO THE WARNING EVEN
THOUGH AMOUNTS COULD BE MARGINAL.

A BAND OF SNOW SHOULD EXTEND FARTHER EAST ONTO THE PLAINS TOWARD
THE WESTERN NEBRASKA PANHANDLE. MOST LIKELY AREA FOR THIS TO OCCUR
IS ACROSS THE NORTHERN ZONES WITH THE INITIAL FRONTAL SURGE. BIG
QUESTIONS FOR THE INTERSTATE 80 CORRIDOR AS H7-H3 RH PROGS SHOW A
SUBSTANTIAL DRY SLOT SNEAKING INTO OUR EXTREME SOUTHEAST CWA. WE
BELIEVE LIGHT ACCUMULATIONS AND INCREASING WINDS TONIGHT WILL BE
ENOUGH TO CAUSE SIGNIFICANT TRAVEL DIFFICULTY...ESPECIALLY ALONG
INTERSTATE 80. DECIDED ON A WINTER WEATHER ADVISORY FROM THE SOUTH
LARAMIE RANGE NORTHEAST INTO THE NORTHERN PANHANDLE. SNOW SHOULD
SLOWLY END ON TUE NIGHT AND WED AS THE SYSTEM DEPARTS...BUT A FEW
SHOWERS WILL PERSIST AS A SECONDARY SHORTWAVE SWINGS AROUND THE
BACK SIDE OF THE LARGER SCALE TROUGH. DESPITE PLENTY OF CLOUDS
PREVENTING MAJOR RADIATIONAL COOLING...H7 TEMPS AS COLD AS -20 C
AT 12Z WED SUGGESTS SUB ZERO READINGS. EXPECT THAT SOME SORT OF
WIND CHILL HEADLINES WILL BE NECESSARY ON THE HEELS OF ONGOING
WINTER WEATHER PRODUCTS. KEPT HIGHS BELOW GUIDANCE FOR BOTH TUE
AND WED WITH WIDESPREAD SNOW AND COLD ADVECTION ALOFT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 AM MST MON MAR 2 2015

00Z MODELS INDICATE NORTHWEST FLOW ALOFT BEHIND EXITING TROUGH
AND UPPER RIDGE EXPANDING EAST TOWARD THE GREAT BASIN. A WEAK
SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE CWA THURSDAY MORNING
WITH LITTLE OR NO ASSOCIATED MOISTURE. 700MB WINDS INCREASE TO
50 KT ALONG THE I-80 CORRIDOR BETWEEN ARLINGTON AND CHEYENNE
WEDNESDAY NIGHT/THURSDAY MORNING. OVER THE NORTH SNOWY RANGE
FOOTHILLS/CENTRAL LARAMIE RANGE. THE CENTER OF UPPER RIDGE MOVES
INTO CA/NV FRIDAY WITH LIGHTER NORTHWEST FLOW. THERE ARE MODEL
DIFFERENCES THIS WEEKEND AS THE ECMWF SHOWS A POTENT SHORTWAVE
TROUGH TRACKING SOUTHEAST FROM ID/WESTERN MT ACROSS WY/CO
SATURDAY...PRODUCING LIGHT PRECIPITATION. THE GFS DOES NOT SHOW
THIS FEATURE BUT AMPLIFIES THE NORTHWEST FLOW ALOFT AS SHORTWAVE
ENERGY MOVES ACROSS THE NORTHERN U.S. FOR NOW...LEFT POPS BELOW
15 PERCENT BUT THEY MAY BE INCREASED LATER IF THE GFS TRENDS
TOWARD THE ECMWF. A COLD FRONT WILL MOVE THROUGH THE REGION
SATURDAY. IT DOES NOT LOOK AS COLD BEHIND THE FRONT COMPARED TO
EARLIER MODEL RUNS. HIGHS THURSDAY WILL BE ABOUT 20 DEGREES WARMER
THAN WEDNESDAY AS DOWNSLOPE WEST-NORTHWEST WINDS DEVELOP LEE OF
LARAMIE RANGE. TEMPERATURES FINALLY WARM TO NEAR SEASONAL NORMALS
FRIDAY WITH HIGHS IN THE 30S AND 40S. IT WILL BE A TAD COOLER FOR
THE PLAINS SATURDAY. UPPER RIDGE BUILDS CLOSER WITH DOWNSLOPE
NORTHWEST FLOW KEEPING TEMPERATURES SEASONABLE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY MORNING)
ISSUED AT 1031 AM MST MON MAR 2 2015

LIFR CONDS WITH SNOW AND LOW CIGS LIKELY THROUGH THE PD AFFECTING
THE KRWL AREA WHILE ELSEWHERE SCTD MVFR CIGS EXPECTED THROUGH THIS
EVENING.  SFC COLD FRONT WILL MOVE SOUTH ACROSS THE AREA LATE THIS
EVENING AND OVERNIGHT WITH MAINLY IFR CONDITIONS BECOMING WIDESPREAD
LATER TONIGHT INTO TUESDAY MORNING.

&&

.FIRE WEATHER...
ISSUED AT 430 AM MST MON MAR 2 2015

NO FIRE WEATHER CONCERNS. SNOW IS EXPECTED TO DEVELOP TODAY AND
BECOME WIDESPREAD TONIGHT AND TUESDAY. SIGNIFICANT ACCUMULATIONS
ARE POSSIBLE...ESPECIALLY IN THE MOUNTAINS AND LOWER ELEVATION
AREAS WEST OF THE LARAMIE RANGE. THE SNOW WILL GRADUALLY DIMINISH
BY TUESDAY NIGHT. AN ARCTIC COLD FRONT WILL BRING BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS FROM TUESDAY NIGHT THROUGH
WEDNESDAY. MODERATING TEMPERATURES ARE EXPECTED LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR WYZ102-106>108-115>117.

     WINTER STORM WARNING UNTIL 6 PM MST TUESDAY FOR WYZ104-105-
     109>114.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 PM MST
     TUESDAY FOR WYZ101-103.

NE...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR NEZ002-003-095-096.

&&

$$

UPDATE...SML
SHORT TERM...CLH
LONG TERM...MJ
AVIATION...RE
FIRE WEATHER...CLH




000
FXUS65 KCYS 021636
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
936 AM MST MON MAR 2 2015

.UPDATE...
ISSUED AT 929 AM MST MON MAR 2 2015

STARTED THE WINTER STORM WARNING FOR ALL OF CARBON COUNTY
EFFECTIVE IMMEDIATELY. SNOW IS ALREADY ACCUMULATING ON THE ROAD
SURFACES ACROSS MUCH OF THE COUNTY WITH 1 TO 2 INCHES OF SNOW ALREADY
ON THE GROUND IN RAWLINS. LATEST GFS SHOWING HIGH SNOW FALL RATES
AND BASED ON MOSAIC RADAR OVER WESTERN COLORADO...THERE IS NOT
MUCH DOUBT SNOW WILL CONTINUE TO INTENSIFY THIS MORNING WITH SNOW
HEAVY AT TIMES THROUGH THIS AFTERNOON. THE REST OF THE WINTER
STORM PRODUCTS LOOK FINE. SOME LIGHT SNOW ACCUMULATIONS WILL
OCCUR AROUND LARAMIE BUT NOT MAIN PRECIPITATION AREA WILL SHIFT
SLIGHTLY WEST THIS AFTERNOON BEFORE SPREADING EAST TONIGHT WITH
THE MAIN UPPER LEVEL FEATURE.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 430 AM MST MON MAR 2 2015

A BUSY FORECAST PERIOD CONTINUES WITH A MAJOR WINTER STORM STILL
ON TRACK FOR MUCH OF THE CWA. MAIN CHALLENGES REVOLVE AROUND THE
TIMING/PLACEMENT OF HEAVIEST SNOWFALL AND WHAT IMPACTS THIS WILL
HAVE TO TRAVEL. DANGEROUS WIND CHILLS WILL UNDOUBTEDLY BECOME AN
ISSUE BY TUE NIGHT AND WED...AND TEMPERATURES WILL HINGE ON CLOUD
COVER AND SNOW DEPTHS HEADING INTO MIDWEEK. MORNING WV SAT IMAGERY
SHOWS DEEP TROUGHING OVER THE WESTERN CONUS. A SEPARATE AND MORE
VIGOROUS PIECE OF ENERGY WAS LOCATED OVER SOUTHERN CAL WITH THE
MUCH ANTICIPATED KICKER SYSTEM DIVING SOUTH ALONG THE WESTERN US
COASTLINE. EXCELLENT MOISTURE FETCH WAS OBSERVED DOWNSTREAM OVER
THE FOUR CORNERS...AS WELL AS GOOD INSTABILITY WITH A FEW RECENT
LIGHTNING STRIKES OVER CA/NV BENEATH THE UPPER LOW. THAT SAID...
CONFIDENCE IS HIGH FOR A HEAVY SNOWFALL EVENT IN OUR CWA.

WE DECIDED TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE
REST OF CARBON COUNTY...KEEPING START/END TIMES THE SAME. WE HAVE
SEEN SOLID RUN-TO-RUN AND MODEL-TO-MODEL CONSISTENCY AMONG BOTH
AMERICAN AND EUROPEAN GUIDANCE OVER THE LAST DAY OR SO. CONSENSUS
IS FOR THE SOUTHERN WAVE TO LIFT NORTHEAST INTO WESTERN CO BY THIS
AFTN WITH AN IMPRESSIVE 160+ KT H25 JET NOSING INTO SOUTHEAST WY
BY 00Z TUE. THIS PLACES OUR WESTERN ZONES IN THE FAVORED LEFT EXIT
REGION FOR A FEW HOURS THIS AFTERNOON...SO A PERIOD OF HEAVY SNOW
BANDING IS LIKELY WITH A SURFACE WARM FRONTAL BOUNDARY ORIENTED
FROM SW TO NE ACROSS THE CWA. NAM AND GFS MUCAPES BETWEEN 100 AND
200 J/KG SUGGESTS SOME CONVECTIVE ELEMENTS...SO RATES COULD EXCEED
AN INCH PER HOUR AT TIMES. SNOWIES AND SIERRA MADRES ARE STILL IN
GOOD SHAPE FOR AROUND 2 FEET OF TOTAL ACCUMULATIONS.

THE MORE WIDESPREAD EVENT HOLDS OFF UNTIL LATER THIS EVENING AND
OVERNIGHT WITH THE COLD FROPA. GFS/NAM/ECMWF ARE ALL IN EXCELLENT
AGREEMENT WITH THE ARCTIC FRONT SURGING SOUTH BETWEEN 06Z AND 12Z
TUE. SIGNIFICANT LLVL COLD ADVECTION SHOULD OCCUR WITH GFS 700 MB
TEMPS OVER CYS FALLING FROM +1C AT 00Z TO -13C AT 12Z TUE. FRONTAL
PASSAGE WILL RESULT IN ENHANCED LLVL CONVERGENCE AND FRONTOGENESIS
ALONG THE LARAMIE RANGE...AND UPSLOPE FLOW MOST PRONOUNCED OVER
THE NORTHERN MOUNTAINS. LATEST RUNS HAVE BEEN HITTING THE NORTH
LARAMIE RANGE HARD WITH AN AVERAGE OF AROUND 0.7 INCH QPF...WHICH
IS NOT SURPRISING WITH STEEPENING LAPSE RATES ALOFT. BEST SUPPORT
WILL BE FAST MOVING...BUT RATES SHOULD BE HIGH ENOUGH TO GET CLOSE
TO A FOOT OF SNOW OVER NORTH FACING SLOPES. WINDS SHOULD COME INTO
PLAY AS WELL AS COLD ADVECTION YIELDS STRONG MIXING OVERNIGHT WITH
30 TO 40 KTS AVAILABLE TO MIX. WENT AHEAD AND ADDED THE NORTHERN
LARAMIE RANGE AND LOWER ELEVATIONS OF CONVERSE TO THE WARNING EVEN
THOUGH AMOUNTS COULD BE MARGINAL.

A BAND OF SNOW SHOULD EXTEND FARTHER EAST ONTO THE PLAINS TOWARD
THE WESTERN NEBRASKA PANHANDLE. MOST LIKELY AREA FOR THIS TO OCCUR
IS ACROSS THE NORTHERN ZONES WITH THE INITIAL FRONTAL SURGE. BIG
QUESTIONS FOR THE INTERSTATE 80 CORRIDOR AS H7-H3 RH PROGS SHOW A
SUBSTANTIAL DRY SLOT SNEAKING INTO OUR EXTREME SOUTHEAST CWA. WE
BELIEVE LIGHT ACCUMULATIONS AND INCREASING WINDS TONIGHT WILL BE
ENOUGH TO CAUSE SIGNIFICANT TRAVEL DIFFICULTY...ESPECIALLY ALONG
INTERSTATE 80. DECIDED ON A WINTER WEATHER ADVISORY FROM THE SOUTH
LARAMIE RANGE NORTHEAST INTO THE NORTHERN PANHANDLE. SNOW SHOULD
SLOWLY END ON TUE NIGHT AND WED AS THE SYSTEM DEPARTS...BUT A FEW
SHOWERS WILL PERSIST AS A SECONDARY SHORTWAVE SWINGS AROUND THE
BACK SIDE OF THE LARGER SCALE TROUGH. DESPITE PLENTY OF CLOUDS
PREVENTING MAJOR RADIATIONAL COOLING...H7 TEMPS AS COLD AS -20 C
AT 12Z WED SUGGESTS SUB ZERO READINGS. EXPECT THAT SOME SORT OF
WIND CHILL HEADLINES WILL BE NECESSARY ON THE HEELS OF ONGOING
WINTER WEATHER PRODUCTS. KEPT HIGHS BELOW GUIDANCE FOR BOTH TUE
AND WED WITH WIDESPREAD SNOW AND COLD ADVECTION ALOFT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 AM MST MON MAR 2 2015

00Z MODELS INDICATE NORTHWEST FLOW ALOFT BEHIND EXITING TROUGH
AND UPPER RIDGE EXPANDING EAST TOWARD THE GREAT BASIN. A WEAK
SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE CWA THURSDAY MORNING
WITH LITTLE OR NO ASSOCIATED MOISTURE. 700MB WINDS INCREASE TO
50 KT ALONG THE I-80 CORRIDOR BETWEEN ARLINGTON AND CHEYENNE
WEDNESDAY NIGHT/THURSDAY MORNING. OVER THE NORTH SNOWY RANGE
FOOTHILLS/CENTRAL LARAMIE RANGE. THE CENTER OF UPPER RIDGE MOVES
INTO CA/NV FRIDAY WITH LIGHTER NORTHWEST FLOW. THERE ARE MODEL
DIFFERENCES THIS WEEKEND AS THE ECMWF SHOWS A POTENT SHORTWAVE
TROUGH TRACKING SOUTHEAST FROM ID/WESTERN MT ACROSS WY/CO
SATURDAY...PRODUCING LIGHT PRECIPITATION. THE GFS DOES NOT SHOW
THIS FEATURE BUT AMPLIFIES THE NORTHWEST FLOW ALOFT AS SHORTWAVE
ENERGY MOVES ACROSS THE NORTHERN U.S. FOR NOW...LEFT POPS BELOW
15 PERCENT BUT THEY MAY BE INCREASED LATER IF THE GFS TRENDS
TOWARD THE ECMWF. A COLD FRONT WILL MOVE THROUGH THE REGION
SATURDAY. IT DOES NOT LOOK AS COLD BEHIND THE FRONT COMPARED TO
EARLIER MODEL RUNS. HIGHS THURSDAY WILL BE ABOUT 20 DEGREES WARMER
THAN WEDNESDAY AS DOWNSLOPE WEST-NORTHWEST WINDS DEVELOP LEE OF
LARAMIE RANGE. TEMPERATURES FINALLY WARM TO NEAR SEASONAL NORMALS
FRIDAY WITH HIGHS IN THE 30S AND 40S. IT WILL BE A TAD COOLER FOR
THE PLAINS SATURDAY. UPPER RIDGE BUILDS CLOSER WITH DOWNSLOPE
NORTHWEST FLOW KEEPING TEMPERATURES SEASONABLE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 300 AM MST MON MAR 2 2015

BRIEF MVFR CIGS/VSBYS ALONG THE KCYS-KSNY ROUTE EARLY THIS MORNING.
OTHERWISE...VFR WILL PREVAIL EAST OF THE LARAMIE RANGE TODAY.
DETERIORATING CONDITIONS WILL DEVELOP WEST OF THE LARAMIE RANGE
THIS MORNING WITH IFR CIGS/VSBYS IN SNOW. THE MOUNTAINS WILL BE
OBSCURED THROUGHOUT THE PERIOD. MVFR TO IFR CIGS/VSBYS THEN DEVELOP
EAST OF THE LARAMIE RANGE THIS AFTERNOON AND EVENING AS SNOW BECOMES
MORE WIDESPREAD. SOUTHERLY WINDS OF 10-15 KT WILL PREVAIL...WITH
PERHAPS SOME GUSTS ABOVE 20 KT POSSIBLE FOR THE PLAINS. WINDS WILL
SHIFT TO NORTHERLY AND BECOME RATHER GUSTY WITH THE PASSAGE OF A
STRONG COLD FRONT LATE TONIGHT.


&&

.FIRE WEATHER...
ISSUED AT 430 AM MST MON MAR 2 2015

NO FIRE WEATHER CONCERNS. SNOW IS EXPECTED TO DEVELOP TODAY AND
BECOME WIDESPREAD TONIGHT AND TUESDAY. SIGNIFICANT ACCUMULATIONS
ARE POSSIBLE...ESPECIALLY IN THE MOUNTAINS AND LOWER ELEVATION
AREAS WEST OF THE LARAMIE RANGE. THE SNOW WILL GRADUALLY DIMINISH
BY TUESDAY NIGHT. AN ARCTIC COLD FRONT WILL BRING BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS FROM TUESDAY NIGHT THROUGH
WEDNESDAY. MODERATING TEMPERATURES ARE EXPECTED LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR WYZ102-106>108-115>117.

     WINTER STORM WARNING UNTIL 6 PM MST TUESDAY FOR WYZ104-105-
     109>114.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 PM MST
     TUESDAY FOR WYZ101-103.

NE...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR NEZ002-003-095-096.

&&

$$

UPDATE...SML
SHORT TERM...CLH
LONG TERM...MJ
AVIATION...MJ
FIRE WEATHER...CLH




000
FXUS65 KCYS 021155
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
455 AM MST MON MAR 2 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 430 AM MST MON MAR 2 2015

A BUSY FORECAST PERIOD CONTINUES WITH A MAJOR WINTER STORM STILL
ON TRACK FOR MUCH OF THE CWA. MAIN CHALLENGES REVOLVE AROUND THE
TIMING/PLACEMENT OF HEAVIEST SNOWFALL AND WHAT IMPACTS THIS WILL
HAVE TO TRAVEL. DANGEROUS WIND CHILLS WILL UNDOUBTEDLY BECOME AN
ISSUE BY TUE NIGHT AND WED...AND TEMPERATURES WILL HINGE ON CLOUD
COVER AND SNOW DEPTHS HEADING INTO MIDWEEK. MORNING WV SAT IMAGERY
SHOWS DEEP TROUGHING OVER THE WESTERN CONUS. A SEPARATE AND MORE
VIGOROUS PIECE OF ENERGY WAS LOCATED OVER SOUTHERN CAL WITH THE
MUCH ANTICIPATED KICKER SYSTEM DIVING SOUTH ALONG THE WESTERN US
COASTLINE. EXCELLENT MOISTURE FETCH WAS OBSERVED DOWNSTREAM OVER
THE FOUR CORNERS...AS WELL AS GOOD INSTABILITY WITH A FEW RECENT
LIGHTNING STRIKES OVER CA/NV BENEATH THE UPPER LOW. THAT SAID...
CONFIDENCE IS HIGH FOR A HEAVY SNOWFALL EVENT IN OUR CWA.

WE DECIDED TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE
REST OF CARBON COUNTY...KEEPING START/END TIMES THE SAME. WE HAVE
SEEN SOLID RUN-TO-RUN AND MODEL-TO-MODEL CONSISTENCY AMONG BOTH
AMERICAN AND EUROPEAN GUIDANCE OVER THE LAST DAY OR SO. CONSENSUS
IS FOR THE SOUTHERN WAVE TO LIFT NORTHEAST INTO WESTERN CO BY THIS
AFTN WITH AN IMPRESSIVE 160+ KT H25 JET NOSING INTO SOUTHEAST WY
BY 00Z TUE. THIS PLACES OUR WESTERN ZONES IN THE FAVORED LEFT EXIT
REGION FOR A FEW HOURS THIS AFTERNOON...SO A PERIOD OF HEAVY SNOW
BANDING IS LIKELY WITH A SURFACE WARM FRONTAL BOUNDARY ORIENTED
FROM SW TO NE ACROSS THE CWA. NAM AND GFS MUCAPES BETWEEN 100 AND
200 J/KG SUGGESTS SOME CONVECTIVE ELEMENTS...SO RATES COULD EXCEED
AN INCH PER HOUR AT TIMES. SNOWIES AND SIERRA MADRES ARE STILL IN
GOOD SHAPE FOR AROUND 2 FEET OF TOTAL ACCUMULATIONS.

THE MORE WIDESPREAD EVENT HOLDS OFF UNTIL LATER THIS EVENING AND
OVERNIGHT WITH THE COLD FROPA. GFS/NAM/ECMWF ARE ALL IN EXCELLENT
AGREEMENT WITH THE ARCTIC FRONT SURGING SOUTH BETWEEN 06Z AND 12Z
TUE. SIGNIFICANT LLVL COLD ADVECTION SHOULD OCCUR WITH GFS 700 MB
TEMPS OVER CYS FALLING FROM +1C AT 00Z TO -13C AT 12Z TUE. FRONTAL
PASSAGE WILL RESULT IN ENHANCED LLVL CONVERGENCE AND FRONTOGENESIS
ALONG THE LARAMIE RANGE...AND UPSLOPE FLOW MOST PRONOUNCED OVER
THE NORTHERN MOUNTAINS. LATEST RUNS HAVE BEEN HITTING THE NORTH
LARAMIE RANGE HARD WITH AN AVERAGE OF AROUND 0.7 INCH QPF...WHICH
IS NOT SURPRISING WITH STEEPENING LAPSE RATES ALOFT. BEST SUPPORT
WILL BE FAST MOVING...BUT RATES SHOULD BE HIGH ENOUGH TO GET CLOSE
TO A FOOT OF SNOW OVER NORTH FACING SLOPES. WINDS SHOULD COME INTO
PLAY AS WELL AS COLD ADVECTION YIELDS STRONG MIXING OVERNIGHT WITH
30 TO 40 KTS AVAILABLE TO MIX. WENT AHEAD AND ADDED THE NORTHERN
LARAMIE RANGE AND LOWER ELEVATIONS OF CONVERSE TO THE WARNING EVEN
THOUGH AMOUNTS COULD BE MARGINAL.

A BAND OF SNOW SHOULD EXTEND FARTHER EAST ONTO THE PLAINS TOWARD
THE WESTERN NEBRASKA PANHANDLE. MOST LIKELY AREA FOR THIS TO OCCUR
IS ACROSS THE NORTHERN ZONES WITH THE INITIAL FRONTAL SURGE. BIG
QUESTIONS FOR THE INTERSTATE 80 CORRIDOR AS H7-H3 RH PROGS SHOW A
SUBSTANTIAL DRY SLOT SNEAKING INTO OUR EXTREME SOUTHEAST CWA. WE
BELIEVE LIGHT ACCUMULATIONS AND INCREASING WINDS TONIGHT WILL BE
ENOUGH TO CAUSE SIGNIFICANT TRAVEL DIFFICULTY...ESPECIALLY ALONG
INTERSTATE 80. DECIDED ON A WINTER WEATHER ADVISORY FROM THE SOUTH
LARAMIE RANGE NORTHEAST INTO THE NORTHERN PANHANDLE. SNOW SHOULD
SLOWLY END ON TUE NIGHT AND WED AS THE SYSTEM DEPARTS...BUT A FEW
SHOWERS WILL PERSIST AS A SECONDARY SHORTWAVE SWINGS AROUND THE
BACK SIDE OF THE LARGER SCALE TROUGH. DESPITE PLENTY OF CLOUDS
PREVENTING MAJOR RADIATIONAL COOLING...H7 TEMPS AS COLD AS -20 C
AT 12Z WED SUGGESTS SUB ZERO READINGS. EXPECT THAT SOME SORT OF
WIND CHILL HEADLINES WILL BE NECESSARY ON THE HEELS OF ONGOING
WINTER WEATHER PRODUCTS. KEPT HIGHS BELOW GUIDANCE FOR BOTH TUE
AND WED WITH WIDESPREAD SNOW AND COLD ADVECTION ALOFT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 AM MST MON MAR 2 2015

00Z MODELS INDICATE NORTHWEST FLOW ALOFT BEHIND EXITING TROUGH
AND UPPER RIDGE EXPANDING EAST TOWARD THE GREAT BASIN. A WEAK
SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE CWA THURSDAY MORNING
WITH LITTLE OR NO ASSOCIATED MOISTURE. 700MB WINDS INCREASE TO
50 KT ALONG THE I-80 CORRIDOR BETWEEN ARLINGTON AND CHEYENNE
WEDNESDAY NIGHT/THURSDAY MORNING. OVER THE NORTH SNOWY RANGE
FOOTHILLS/CENTRAL LARAMIE RANGE. THE CENTER OF UPPER RIDGE MOVES
INTO CA/NV FRIDAY WITH LIGHTER NORTHWEST FLOW. THERE ARE MODEL
DIFFERENCES THIS WEEKEND AS THE ECMWF SHOWS A POTENT SHORTWAVE
TROUGH TRACKING SOUTHEAST FROM ID/WESTERN MT ACROSS WY/CO
SATURDAY...PRODUCING LIGHT PRECIPITATION. THE GFS DOES NOT SHOW
THIS FEATURE BUT AMPLIFIES THE NORTHWEST FLOW ALOFT AS SHORTWAVE
ENERGY MOVES ACROSS THE NORTHERN U.S. FOR NOW...LEFT POPS BELOW
15 PERCENT BUT THEY MAY BE INCREASED LATER IF THE GFS TRENDS
TOWARD THE ECMWF. A COLD FRONT WILL MOVE THROUGH THE REGION
SATURDAY. IT DOES NOT LOOK AS COLD BEHIND THE FRONT COMPARED TO
EARLIER MODEL RUNS. HIGHS THURSDAY WILL BE ABOUT 20 DEGREES WARMER
THAN WEDNESDAY AS DOWNSLOPE WEST-NORTHWEST WINDS DEVELOP LEE OF
LARAMIE RANGE. TEMPERATURES FINALLY WARM TO NEAR SEASONAL NORMALS
FRIDAY WITH HIGHS IN THE 30S AND 40S. IT WILL BE A TAD COOLER FOR
THE PLAINS SATURDAY. UPPER RIDGE BUILDS CLOSER WITH DOWNSLOPE
NORTHWEST FLOW KEEPING TEMPERATURES SEASONABLE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 300 AM MST MON MAR 2 2015

BRIEF MVFR CIGS/VSBYS ALONG THE KCYS-KSNY ROUTE EARLY THIS MORNING.
OTHERWISE...VFR WILL PREVAIL EAST OF THE LARAMIE RANGE TODAY.
DETERIORATING CONDITIONS WILL DEVELOP WEST OF THE LARAMIE RANGE
THIS MORNING WITH IFR CIGS/VSBYS IN SNOW. THE MOUNTAINS WILL BE
OBSCURED THROUGHOUT THE PERIOD. MVFR TO IFR CIGS/VSBYS THEN DEVELOP
EAST OF THE LARAMIE RANGE THIS AFTERNOON AND EVENING AS SNOW BECOMES
MORE WIDESPREAD. SOUTHERLY WINDS OF 10-15 KT WILL PREVAIL...WITH
PERHAPS SOME GUSTS ABOVE 20 KT POSSIBLE FOR THE PLAINS. WINDS WILL
SHIFT TO NORTHERLY AND BECOME RATHER GUSTY WITH THE PASSAGE OF A
STRONG COLD FRONT LATE TONIGHT.

&&

.FIRE WEATHER...
ISSUED AT 430 AM MST MON MAR 2 2015

NO FIRE WEATHER CONCERNS. SNOW IS EXPECTED TO DEVELOP TODAY AND
BECOME WIDESPREAD TONIGHT AND TUESDAY. SIGNIFICANT ACCUMULATIONS
ARE POSSIBLE...ESPECIALLY IN THE MOUNTAINS AND LOWER ELEVATION
AREAS WEST OF THE LARAMIE RANGE. THE SNOW WILL GRADUALLY DIMINISH
BY TUESDAY NIGHT. AN ARCTIC COLD FRONT WILL BRING BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS FROM TUESDAY NIGHT THROUGH
WEDNESDAY. MODERATING TEMPERATURES ARE EXPECTED LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR WYZ102-106>108-115>117.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 PM MST
     TUESDAY FOR WYZ101-103>105-109-110.

     WINTER STORM WARNING UNTIL 6 PM MST TUESDAY FOR WYZ111>114.

NE...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR NEZ002-003-095-096.

&&

$$

SHORT TERM...CLH
LONG TERM...MJ
AVIATION...MJ
FIRE WEATHER...CLH




000
FXUS65 KCYS 021155
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
455 AM MST MON MAR 2 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 430 AM MST MON MAR 2 2015

A BUSY FORECAST PERIOD CONTINUES WITH A MAJOR WINTER STORM STILL
ON TRACK FOR MUCH OF THE CWA. MAIN CHALLENGES REVOLVE AROUND THE
TIMING/PLACEMENT OF HEAVIEST SNOWFALL AND WHAT IMPACTS THIS WILL
HAVE TO TRAVEL. DANGEROUS WIND CHILLS WILL UNDOUBTEDLY BECOME AN
ISSUE BY TUE NIGHT AND WED...AND TEMPERATURES WILL HINGE ON CLOUD
COVER AND SNOW DEPTHS HEADING INTO MIDWEEK. MORNING WV SAT IMAGERY
SHOWS DEEP TROUGHING OVER THE WESTERN CONUS. A SEPARATE AND MORE
VIGOROUS PIECE OF ENERGY WAS LOCATED OVER SOUTHERN CAL WITH THE
MUCH ANTICIPATED KICKER SYSTEM DIVING SOUTH ALONG THE WESTERN US
COASTLINE. EXCELLENT MOISTURE FETCH WAS OBSERVED DOWNSTREAM OVER
THE FOUR CORNERS...AS WELL AS GOOD INSTABILITY WITH A FEW RECENT
LIGHTNING STRIKES OVER CA/NV BENEATH THE UPPER LOW. THAT SAID...
CONFIDENCE IS HIGH FOR A HEAVY SNOWFALL EVENT IN OUR CWA.

WE DECIDED TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE
REST OF CARBON COUNTY...KEEPING START/END TIMES THE SAME. WE HAVE
SEEN SOLID RUN-TO-RUN AND MODEL-TO-MODEL CONSISTENCY AMONG BOTH
AMERICAN AND EUROPEAN GUIDANCE OVER THE LAST DAY OR SO. CONSENSUS
IS FOR THE SOUTHERN WAVE TO LIFT NORTHEAST INTO WESTERN CO BY THIS
AFTN WITH AN IMPRESSIVE 160+ KT H25 JET NOSING INTO SOUTHEAST WY
BY 00Z TUE. THIS PLACES OUR WESTERN ZONES IN THE FAVORED LEFT EXIT
REGION FOR A FEW HOURS THIS AFTERNOON...SO A PERIOD OF HEAVY SNOW
BANDING IS LIKELY WITH A SURFACE WARM FRONTAL BOUNDARY ORIENTED
FROM SW TO NE ACROSS THE CWA. NAM AND GFS MUCAPES BETWEEN 100 AND
200 J/KG SUGGESTS SOME CONVECTIVE ELEMENTS...SO RATES COULD EXCEED
AN INCH PER HOUR AT TIMES. SNOWIES AND SIERRA MADRES ARE STILL IN
GOOD SHAPE FOR AROUND 2 FEET OF TOTAL ACCUMULATIONS.

THE MORE WIDESPREAD EVENT HOLDS OFF UNTIL LATER THIS EVENING AND
OVERNIGHT WITH THE COLD FROPA. GFS/NAM/ECMWF ARE ALL IN EXCELLENT
AGREEMENT WITH THE ARCTIC FRONT SURGING SOUTH BETWEEN 06Z AND 12Z
TUE. SIGNIFICANT LLVL COLD ADVECTION SHOULD OCCUR WITH GFS 700 MB
TEMPS OVER CYS FALLING FROM +1C AT 00Z TO -13C AT 12Z TUE. FRONTAL
PASSAGE WILL RESULT IN ENHANCED LLVL CONVERGENCE AND FRONTOGENESIS
ALONG THE LARAMIE RANGE...AND UPSLOPE FLOW MOST PRONOUNCED OVER
THE NORTHERN MOUNTAINS. LATEST RUNS HAVE BEEN HITTING THE NORTH
LARAMIE RANGE HARD WITH AN AVERAGE OF AROUND 0.7 INCH QPF...WHICH
IS NOT SURPRISING WITH STEEPENING LAPSE RATES ALOFT. BEST SUPPORT
WILL BE FAST MOVING...BUT RATES SHOULD BE HIGH ENOUGH TO GET CLOSE
TO A FOOT OF SNOW OVER NORTH FACING SLOPES. WINDS SHOULD COME INTO
PLAY AS WELL AS COLD ADVECTION YIELDS STRONG MIXING OVERNIGHT WITH
30 TO 40 KTS AVAILABLE TO MIX. WENT AHEAD AND ADDED THE NORTHERN
LARAMIE RANGE AND LOWER ELEVATIONS OF CONVERSE TO THE WARNING EVEN
THOUGH AMOUNTS COULD BE MARGINAL.

A BAND OF SNOW SHOULD EXTEND FARTHER EAST ONTO THE PLAINS TOWARD
THE WESTERN NEBRASKA PANHANDLE. MOST LIKELY AREA FOR THIS TO OCCUR
IS ACROSS THE NORTHERN ZONES WITH THE INITIAL FRONTAL SURGE. BIG
QUESTIONS FOR THE INTERSTATE 80 CORRIDOR AS H7-H3 RH PROGS SHOW A
SUBSTANTIAL DRY SLOT SNEAKING INTO OUR EXTREME SOUTHEAST CWA. WE
BELIEVE LIGHT ACCUMULATIONS AND INCREASING WINDS TONIGHT WILL BE
ENOUGH TO CAUSE SIGNIFICANT TRAVEL DIFFICULTY...ESPECIALLY ALONG
INTERSTATE 80. DECIDED ON A WINTER WEATHER ADVISORY FROM THE SOUTH
LARAMIE RANGE NORTHEAST INTO THE NORTHERN PANHANDLE. SNOW SHOULD
SLOWLY END ON TUE NIGHT AND WED AS THE SYSTEM DEPARTS...BUT A FEW
SHOWERS WILL PERSIST AS A SECONDARY SHORTWAVE SWINGS AROUND THE
BACK SIDE OF THE LARGER SCALE TROUGH. DESPITE PLENTY OF CLOUDS
PREVENTING MAJOR RADIATIONAL COOLING...H7 TEMPS AS COLD AS -20 C
AT 12Z WED SUGGESTS SUB ZERO READINGS. EXPECT THAT SOME SORT OF
WIND CHILL HEADLINES WILL BE NECESSARY ON THE HEELS OF ONGOING
WINTER WEATHER PRODUCTS. KEPT HIGHS BELOW GUIDANCE FOR BOTH TUE
AND WED WITH WIDESPREAD SNOW AND COLD ADVECTION ALOFT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 AM MST MON MAR 2 2015

00Z MODELS INDICATE NORTHWEST FLOW ALOFT BEHIND EXITING TROUGH
AND UPPER RIDGE EXPANDING EAST TOWARD THE GREAT BASIN. A WEAK
SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE CWA THURSDAY MORNING
WITH LITTLE OR NO ASSOCIATED MOISTURE. 700MB WINDS INCREASE TO
50 KT ALONG THE I-80 CORRIDOR BETWEEN ARLINGTON AND CHEYENNE
WEDNESDAY NIGHT/THURSDAY MORNING. OVER THE NORTH SNOWY RANGE
FOOTHILLS/CENTRAL LARAMIE RANGE. THE CENTER OF UPPER RIDGE MOVES
INTO CA/NV FRIDAY WITH LIGHTER NORTHWEST FLOW. THERE ARE MODEL
DIFFERENCES THIS WEEKEND AS THE ECMWF SHOWS A POTENT SHORTWAVE
TROUGH TRACKING SOUTHEAST FROM ID/WESTERN MT ACROSS WY/CO
SATURDAY...PRODUCING LIGHT PRECIPITATION. THE GFS DOES NOT SHOW
THIS FEATURE BUT AMPLIFIES THE NORTHWEST FLOW ALOFT AS SHORTWAVE
ENERGY MOVES ACROSS THE NORTHERN U.S. FOR NOW...LEFT POPS BELOW
15 PERCENT BUT THEY MAY BE INCREASED LATER IF THE GFS TRENDS
TOWARD THE ECMWF. A COLD FRONT WILL MOVE THROUGH THE REGION
SATURDAY. IT DOES NOT LOOK AS COLD BEHIND THE FRONT COMPARED TO
EARLIER MODEL RUNS. HIGHS THURSDAY WILL BE ABOUT 20 DEGREES WARMER
THAN WEDNESDAY AS DOWNSLOPE WEST-NORTHWEST WINDS DEVELOP LEE OF
LARAMIE RANGE. TEMPERATURES FINALLY WARM TO NEAR SEASONAL NORMALS
FRIDAY WITH HIGHS IN THE 30S AND 40S. IT WILL BE A TAD COOLER FOR
THE PLAINS SATURDAY. UPPER RIDGE BUILDS CLOSER WITH DOWNSLOPE
NORTHWEST FLOW KEEPING TEMPERATURES SEASONABLE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 300 AM MST MON MAR 2 2015

BRIEF MVFR CIGS/VSBYS ALONG THE KCYS-KSNY ROUTE EARLY THIS MORNING.
OTHERWISE...VFR WILL PREVAIL EAST OF THE LARAMIE RANGE TODAY.
DETERIORATING CONDITIONS WILL DEVELOP WEST OF THE LARAMIE RANGE
THIS MORNING WITH IFR CIGS/VSBYS IN SNOW. THE MOUNTAINS WILL BE
OBSCURED THROUGHOUT THE PERIOD. MVFR TO IFR CIGS/VSBYS THEN DEVELOP
EAST OF THE LARAMIE RANGE THIS AFTERNOON AND EVENING AS SNOW BECOMES
MORE WIDESPREAD. SOUTHERLY WINDS OF 10-15 KT WILL PREVAIL...WITH
PERHAPS SOME GUSTS ABOVE 20 KT POSSIBLE FOR THE PLAINS. WINDS WILL
SHIFT TO NORTHERLY AND BECOME RATHER GUSTY WITH THE PASSAGE OF A
STRONG COLD FRONT LATE TONIGHT.

&&

.FIRE WEATHER...
ISSUED AT 430 AM MST MON MAR 2 2015

NO FIRE WEATHER CONCERNS. SNOW IS EXPECTED TO DEVELOP TODAY AND
BECOME WIDESPREAD TONIGHT AND TUESDAY. SIGNIFICANT ACCUMULATIONS
ARE POSSIBLE...ESPECIALLY IN THE MOUNTAINS AND LOWER ELEVATION
AREAS WEST OF THE LARAMIE RANGE. THE SNOW WILL GRADUALLY DIMINISH
BY TUESDAY NIGHT. AN ARCTIC COLD FRONT WILL BRING BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS FROM TUESDAY NIGHT THROUGH
WEDNESDAY. MODERATING TEMPERATURES ARE EXPECTED LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR WYZ102-106>108-115>117.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 PM MST
     TUESDAY FOR WYZ101-103>105-109-110.

     WINTER STORM WARNING UNTIL 6 PM MST TUESDAY FOR WYZ111>114.

NE...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR NEZ002-003-095-096.

&&

$$

SHORT TERM...CLH
LONG TERM...MJ
AVIATION...MJ
FIRE WEATHER...CLH




000
FXUS65 KCYS 021155
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
455 AM MST MON MAR 2 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 430 AM MST MON MAR 2 2015

A BUSY FORECAST PERIOD CONTINUES WITH A MAJOR WINTER STORM STILL
ON TRACK FOR MUCH OF THE CWA. MAIN CHALLENGES REVOLVE AROUND THE
TIMING/PLACEMENT OF HEAVIEST SNOWFALL AND WHAT IMPACTS THIS WILL
HAVE TO TRAVEL. DANGEROUS WIND CHILLS WILL UNDOUBTEDLY BECOME AN
ISSUE BY TUE NIGHT AND WED...AND TEMPERATURES WILL HINGE ON CLOUD
COVER AND SNOW DEPTHS HEADING INTO MIDWEEK. MORNING WV SAT IMAGERY
SHOWS DEEP TROUGHING OVER THE WESTERN CONUS. A SEPARATE AND MORE
VIGOROUS PIECE OF ENERGY WAS LOCATED OVER SOUTHERN CAL WITH THE
MUCH ANTICIPATED KICKER SYSTEM DIVING SOUTH ALONG THE WESTERN US
COASTLINE. EXCELLENT MOISTURE FETCH WAS OBSERVED DOWNSTREAM OVER
THE FOUR CORNERS...AS WELL AS GOOD INSTABILITY WITH A FEW RECENT
LIGHTNING STRIKES OVER CA/NV BENEATH THE UPPER LOW. THAT SAID...
CONFIDENCE IS HIGH FOR A HEAVY SNOWFALL EVENT IN OUR CWA.

WE DECIDED TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE
REST OF CARBON COUNTY...KEEPING START/END TIMES THE SAME. WE HAVE
SEEN SOLID RUN-TO-RUN AND MODEL-TO-MODEL CONSISTENCY AMONG BOTH
AMERICAN AND EUROPEAN GUIDANCE OVER THE LAST DAY OR SO. CONSENSUS
IS FOR THE SOUTHERN WAVE TO LIFT NORTHEAST INTO WESTERN CO BY THIS
AFTN WITH AN IMPRESSIVE 160+ KT H25 JET NOSING INTO SOUTHEAST WY
BY 00Z TUE. THIS PLACES OUR WESTERN ZONES IN THE FAVORED LEFT EXIT
REGION FOR A FEW HOURS THIS AFTERNOON...SO A PERIOD OF HEAVY SNOW
BANDING IS LIKELY WITH A SURFACE WARM FRONTAL BOUNDARY ORIENTED
FROM SW TO NE ACROSS THE CWA. NAM AND GFS MUCAPES BETWEEN 100 AND
200 J/KG SUGGESTS SOME CONVECTIVE ELEMENTS...SO RATES COULD EXCEED
AN INCH PER HOUR AT TIMES. SNOWIES AND SIERRA MADRES ARE STILL IN
GOOD SHAPE FOR AROUND 2 FEET OF TOTAL ACCUMULATIONS.

THE MORE WIDESPREAD EVENT HOLDS OFF UNTIL LATER THIS EVENING AND
OVERNIGHT WITH THE COLD FROPA. GFS/NAM/ECMWF ARE ALL IN EXCELLENT
AGREEMENT WITH THE ARCTIC FRONT SURGING SOUTH BETWEEN 06Z AND 12Z
TUE. SIGNIFICANT LLVL COLD ADVECTION SHOULD OCCUR WITH GFS 700 MB
TEMPS OVER CYS FALLING FROM +1C AT 00Z TO -13C AT 12Z TUE. FRONTAL
PASSAGE WILL RESULT IN ENHANCED LLVL CONVERGENCE AND FRONTOGENESIS
ALONG THE LARAMIE RANGE...AND UPSLOPE FLOW MOST PRONOUNCED OVER
THE NORTHERN MOUNTAINS. LATEST RUNS HAVE BEEN HITTING THE NORTH
LARAMIE RANGE HARD WITH AN AVERAGE OF AROUND 0.7 INCH QPF...WHICH
IS NOT SURPRISING WITH STEEPENING LAPSE RATES ALOFT. BEST SUPPORT
WILL BE FAST MOVING...BUT RATES SHOULD BE HIGH ENOUGH TO GET CLOSE
TO A FOOT OF SNOW OVER NORTH FACING SLOPES. WINDS SHOULD COME INTO
PLAY AS WELL AS COLD ADVECTION YIELDS STRONG MIXING OVERNIGHT WITH
30 TO 40 KTS AVAILABLE TO MIX. WENT AHEAD AND ADDED THE NORTHERN
LARAMIE RANGE AND LOWER ELEVATIONS OF CONVERSE TO THE WARNING EVEN
THOUGH AMOUNTS COULD BE MARGINAL.

A BAND OF SNOW SHOULD EXTEND FARTHER EAST ONTO THE PLAINS TOWARD
THE WESTERN NEBRASKA PANHANDLE. MOST LIKELY AREA FOR THIS TO OCCUR
IS ACROSS THE NORTHERN ZONES WITH THE INITIAL FRONTAL SURGE. BIG
QUESTIONS FOR THE INTERSTATE 80 CORRIDOR AS H7-H3 RH PROGS SHOW A
SUBSTANTIAL DRY SLOT SNEAKING INTO OUR EXTREME SOUTHEAST CWA. WE
BELIEVE LIGHT ACCUMULATIONS AND INCREASING WINDS TONIGHT WILL BE
ENOUGH TO CAUSE SIGNIFICANT TRAVEL DIFFICULTY...ESPECIALLY ALONG
INTERSTATE 80. DECIDED ON A WINTER WEATHER ADVISORY FROM THE SOUTH
LARAMIE RANGE NORTHEAST INTO THE NORTHERN PANHANDLE. SNOW SHOULD
SLOWLY END ON TUE NIGHT AND WED AS THE SYSTEM DEPARTS...BUT A FEW
SHOWERS WILL PERSIST AS A SECONDARY SHORTWAVE SWINGS AROUND THE
BACK SIDE OF THE LARGER SCALE TROUGH. DESPITE PLENTY OF CLOUDS
PREVENTING MAJOR RADIATIONAL COOLING...H7 TEMPS AS COLD AS -20 C
AT 12Z WED SUGGESTS SUB ZERO READINGS. EXPECT THAT SOME SORT OF
WIND CHILL HEADLINES WILL BE NECESSARY ON THE HEELS OF ONGOING
WINTER WEATHER PRODUCTS. KEPT HIGHS BELOW GUIDANCE FOR BOTH TUE
AND WED WITH WIDESPREAD SNOW AND COLD ADVECTION ALOFT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 AM MST MON MAR 2 2015

00Z MODELS INDICATE NORTHWEST FLOW ALOFT BEHIND EXITING TROUGH
AND UPPER RIDGE EXPANDING EAST TOWARD THE GREAT BASIN. A WEAK
SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE CWA THURSDAY MORNING
WITH LITTLE OR NO ASSOCIATED MOISTURE. 700MB WINDS INCREASE TO
50 KT ALONG THE I-80 CORRIDOR BETWEEN ARLINGTON AND CHEYENNE
WEDNESDAY NIGHT/THURSDAY MORNING. OVER THE NORTH SNOWY RANGE
FOOTHILLS/CENTRAL LARAMIE RANGE. THE CENTER OF UPPER RIDGE MOVES
INTO CA/NV FRIDAY WITH LIGHTER NORTHWEST FLOW. THERE ARE MODEL
DIFFERENCES THIS WEEKEND AS THE ECMWF SHOWS A POTENT SHORTWAVE
TROUGH TRACKING SOUTHEAST FROM ID/WESTERN MT ACROSS WY/CO
SATURDAY...PRODUCING LIGHT PRECIPITATION. THE GFS DOES NOT SHOW
THIS FEATURE BUT AMPLIFIES THE NORTHWEST FLOW ALOFT AS SHORTWAVE
ENERGY MOVES ACROSS THE NORTHERN U.S. FOR NOW...LEFT POPS BELOW
15 PERCENT BUT THEY MAY BE INCREASED LATER IF THE GFS TRENDS
TOWARD THE ECMWF. A COLD FRONT WILL MOVE THROUGH THE REGION
SATURDAY. IT DOES NOT LOOK AS COLD BEHIND THE FRONT COMPARED TO
EARLIER MODEL RUNS. HIGHS THURSDAY WILL BE ABOUT 20 DEGREES WARMER
THAN WEDNESDAY AS DOWNSLOPE WEST-NORTHWEST WINDS DEVELOP LEE OF
LARAMIE RANGE. TEMPERATURES FINALLY WARM TO NEAR SEASONAL NORMALS
FRIDAY WITH HIGHS IN THE 30S AND 40S. IT WILL BE A TAD COOLER FOR
THE PLAINS SATURDAY. UPPER RIDGE BUILDS CLOSER WITH DOWNSLOPE
NORTHWEST FLOW KEEPING TEMPERATURES SEASONABLE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 300 AM MST MON MAR 2 2015

BRIEF MVFR CIGS/VSBYS ALONG THE KCYS-KSNY ROUTE EARLY THIS MORNING.
OTHERWISE...VFR WILL PREVAIL EAST OF THE LARAMIE RANGE TODAY.
DETERIORATING CONDITIONS WILL DEVELOP WEST OF THE LARAMIE RANGE
THIS MORNING WITH IFR CIGS/VSBYS IN SNOW. THE MOUNTAINS WILL BE
OBSCURED THROUGHOUT THE PERIOD. MVFR TO IFR CIGS/VSBYS THEN DEVELOP
EAST OF THE LARAMIE RANGE THIS AFTERNOON AND EVENING AS SNOW BECOMES
MORE WIDESPREAD. SOUTHERLY WINDS OF 10-15 KT WILL PREVAIL...WITH
PERHAPS SOME GUSTS ABOVE 20 KT POSSIBLE FOR THE PLAINS. WINDS WILL
SHIFT TO NORTHERLY AND BECOME RATHER GUSTY WITH THE PASSAGE OF A
STRONG COLD FRONT LATE TONIGHT.

&&

.FIRE WEATHER...
ISSUED AT 430 AM MST MON MAR 2 2015

NO FIRE WEATHER CONCERNS. SNOW IS EXPECTED TO DEVELOP TODAY AND
BECOME WIDESPREAD TONIGHT AND TUESDAY. SIGNIFICANT ACCUMULATIONS
ARE POSSIBLE...ESPECIALLY IN THE MOUNTAINS AND LOWER ELEVATION
AREAS WEST OF THE LARAMIE RANGE. THE SNOW WILL GRADUALLY DIMINISH
BY TUESDAY NIGHT. AN ARCTIC COLD FRONT WILL BRING BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS FROM TUESDAY NIGHT THROUGH
WEDNESDAY. MODERATING TEMPERATURES ARE EXPECTED LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR WYZ102-106>108-115>117.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 PM MST
     TUESDAY FOR WYZ101-103>105-109-110.

     WINTER STORM WARNING UNTIL 6 PM MST TUESDAY FOR WYZ111>114.

NE...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR NEZ002-003-095-096.

&&

$$

SHORT TERM...CLH
LONG TERM...MJ
AVIATION...MJ
FIRE WEATHER...CLH




000
FXUS65 KCYS 021155
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
455 AM MST MON MAR 2 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY)
ISSUED AT 430 AM MST MON MAR 2 2015

A BUSY FORECAST PERIOD CONTINUES WITH A MAJOR WINTER STORM STILL
ON TRACK FOR MUCH OF THE CWA. MAIN CHALLENGES REVOLVE AROUND THE
TIMING/PLACEMENT OF HEAVIEST SNOWFALL AND WHAT IMPACTS THIS WILL
HAVE TO TRAVEL. DANGEROUS WIND CHILLS WILL UNDOUBTEDLY BECOME AN
ISSUE BY TUE NIGHT AND WED...AND TEMPERATURES WILL HINGE ON CLOUD
COVER AND SNOW DEPTHS HEADING INTO MIDWEEK. MORNING WV SAT IMAGERY
SHOWS DEEP TROUGHING OVER THE WESTERN CONUS. A SEPARATE AND MORE
VIGOROUS PIECE OF ENERGY WAS LOCATED OVER SOUTHERN CAL WITH THE
MUCH ANTICIPATED KICKER SYSTEM DIVING SOUTH ALONG THE WESTERN US
COASTLINE. EXCELLENT MOISTURE FETCH WAS OBSERVED DOWNSTREAM OVER
THE FOUR CORNERS...AS WELL AS GOOD INSTABILITY WITH A FEW RECENT
LIGHTNING STRIKES OVER CA/NV BENEATH THE UPPER LOW. THAT SAID...
CONFIDENCE IS HIGH FOR A HEAVY SNOWFALL EVENT IN OUR CWA.

WE DECIDED TO UPGRADE THE WINTER STORM WATCH TO A WARNING FOR THE
REST OF CARBON COUNTY...KEEPING START/END TIMES THE SAME. WE HAVE
SEEN SOLID RUN-TO-RUN AND MODEL-TO-MODEL CONSISTENCY AMONG BOTH
AMERICAN AND EUROPEAN GUIDANCE OVER THE LAST DAY OR SO. CONSENSUS
IS FOR THE SOUTHERN WAVE TO LIFT NORTHEAST INTO WESTERN CO BY THIS
AFTN WITH AN IMPRESSIVE 160+ KT H25 JET NOSING INTO SOUTHEAST WY
BY 00Z TUE. THIS PLACES OUR WESTERN ZONES IN THE FAVORED LEFT EXIT
REGION FOR A FEW HOURS THIS AFTERNOON...SO A PERIOD OF HEAVY SNOW
BANDING IS LIKELY WITH A SURFACE WARM FRONTAL BOUNDARY ORIENTED
FROM SW TO NE ACROSS THE CWA. NAM AND GFS MUCAPES BETWEEN 100 AND
200 J/KG SUGGESTS SOME CONVECTIVE ELEMENTS...SO RATES COULD EXCEED
AN INCH PER HOUR AT TIMES. SNOWIES AND SIERRA MADRES ARE STILL IN
GOOD SHAPE FOR AROUND 2 FEET OF TOTAL ACCUMULATIONS.

THE MORE WIDESPREAD EVENT HOLDS OFF UNTIL LATER THIS EVENING AND
OVERNIGHT WITH THE COLD FROPA. GFS/NAM/ECMWF ARE ALL IN EXCELLENT
AGREEMENT WITH THE ARCTIC FRONT SURGING SOUTH BETWEEN 06Z AND 12Z
TUE. SIGNIFICANT LLVL COLD ADVECTION SHOULD OCCUR WITH GFS 700 MB
TEMPS OVER CYS FALLING FROM +1C AT 00Z TO -13C AT 12Z TUE. FRONTAL
PASSAGE WILL RESULT IN ENHANCED LLVL CONVERGENCE AND FRONTOGENESIS
ALONG THE LARAMIE RANGE...AND UPSLOPE FLOW MOST PRONOUNCED OVER
THE NORTHERN MOUNTAINS. LATEST RUNS HAVE BEEN HITTING THE NORTH
LARAMIE RANGE HARD WITH AN AVERAGE OF AROUND 0.7 INCH QPF...WHICH
IS NOT SURPRISING WITH STEEPENING LAPSE RATES ALOFT. BEST SUPPORT
WILL BE FAST MOVING...BUT RATES SHOULD BE HIGH ENOUGH TO GET CLOSE
TO A FOOT OF SNOW OVER NORTH FACING SLOPES. WINDS SHOULD COME INTO
PLAY AS WELL AS COLD ADVECTION YIELDS STRONG MIXING OVERNIGHT WITH
30 TO 40 KTS AVAILABLE TO MIX. WENT AHEAD AND ADDED THE NORTHERN
LARAMIE RANGE AND LOWER ELEVATIONS OF CONVERSE TO THE WARNING EVEN
THOUGH AMOUNTS COULD BE MARGINAL.

A BAND OF SNOW SHOULD EXTEND FARTHER EAST ONTO THE PLAINS TOWARD
THE WESTERN NEBRASKA PANHANDLE. MOST LIKELY AREA FOR THIS TO OCCUR
IS ACROSS THE NORTHERN ZONES WITH THE INITIAL FRONTAL SURGE. BIG
QUESTIONS FOR THE INTERSTATE 80 CORRIDOR AS H7-H3 RH PROGS SHOW A
SUBSTANTIAL DRY SLOT SNEAKING INTO OUR EXTREME SOUTHEAST CWA. WE
BELIEVE LIGHT ACCUMULATIONS AND INCREASING WINDS TONIGHT WILL BE
ENOUGH TO CAUSE SIGNIFICANT TRAVEL DIFFICULTY...ESPECIALLY ALONG
INTERSTATE 80. DECIDED ON A WINTER WEATHER ADVISORY FROM THE SOUTH
LARAMIE RANGE NORTHEAST INTO THE NORTHERN PANHANDLE. SNOW SHOULD
SLOWLY END ON TUE NIGHT AND WED AS THE SYSTEM DEPARTS...BUT A FEW
SHOWERS WILL PERSIST AS A SECONDARY SHORTWAVE SWINGS AROUND THE
BACK SIDE OF THE LARGER SCALE TROUGH. DESPITE PLENTY OF CLOUDS
PREVENTING MAJOR RADIATIONAL COOLING...H7 TEMPS AS COLD AS -20 C
AT 12Z WED SUGGESTS SUB ZERO READINGS. EXPECT THAT SOME SORT OF
WIND CHILL HEADLINES WILL BE NECESSARY ON THE HEELS OF ONGOING
WINTER WEATHER PRODUCTS. KEPT HIGHS BELOW GUIDANCE FOR BOTH TUE
AND WED WITH WIDESPREAD SNOW AND COLD ADVECTION ALOFT.

.LONG TERM...(WEDNESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 400 AM MST MON MAR 2 2015

00Z MODELS INDICATE NORTHWEST FLOW ALOFT BEHIND EXITING TROUGH
AND UPPER RIDGE EXPANDING EAST TOWARD THE GREAT BASIN. A WEAK
SHORTWAVE TROUGH MOVES SOUTHEAST ACROSS THE CWA THURSDAY MORNING
WITH LITTLE OR NO ASSOCIATED MOISTURE. 700MB WINDS INCREASE TO
50 KT ALONG THE I-80 CORRIDOR BETWEEN ARLINGTON AND CHEYENNE
WEDNESDAY NIGHT/THURSDAY MORNING. OVER THE NORTH SNOWY RANGE
FOOTHILLS/CENTRAL LARAMIE RANGE. THE CENTER OF UPPER RIDGE MOVES
INTO CA/NV FRIDAY WITH LIGHTER NORTHWEST FLOW. THERE ARE MODEL
DIFFERENCES THIS WEEKEND AS THE ECMWF SHOWS A POTENT SHORTWAVE
TROUGH TRACKING SOUTHEAST FROM ID/WESTERN MT ACROSS WY/CO
SATURDAY...PRODUCING LIGHT PRECIPITATION. THE GFS DOES NOT SHOW
THIS FEATURE BUT AMPLIFIES THE NORTHWEST FLOW ALOFT AS SHORTWAVE
ENERGY MOVES ACROSS THE NORTHERN U.S. FOR NOW...LEFT POPS BELOW
15 PERCENT BUT THEY MAY BE INCREASED LATER IF THE GFS TRENDS
TOWARD THE ECMWF. A COLD FRONT WILL MOVE THROUGH THE REGION
SATURDAY. IT DOES NOT LOOK AS COLD BEHIND THE FRONT COMPARED TO
EARLIER MODEL RUNS. HIGHS THURSDAY WILL BE ABOUT 20 DEGREES WARMER
THAN WEDNESDAY AS DOWNSLOPE WEST-NORTHWEST WINDS DEVELOP LEE OF
LARAMIE RANGE. TEMPERATURES FINALLY WARM TO NEAR SEASONAL NORMALS
FRIDAY WITH HIGHS IN THE 30S AND 40S. IT WILL BE A TAD COOLER FOR
THE PLAINS SATURDAY. UPPER RIDGE BUILDS CLOSER WITH DOWNSLOPE
NORTHWEST FLOW KEEPING TEMPERATURES SEASONABLE.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 300 AM MST MON MAR 2 2015

BRIEF MVFR CIGS/VSBYS ALONG THE KCYS-KSNY ROUTE EARLY THIS MORNING.
OTHERWISE...VFR WILL PREVAIL EAST OF THE LARAMIE RANGE TODAY.
DETERIORATING CONDITIONS WILL DEVELOP WEST OF THE LARAMIE RANGE
THIS MORNING WITH IFR CIGS/VSBYS IN SNOW. THE MOUNTAINS WILL BE
OBSCURED THROUGHOUT THE PERIOD. MVFR TO IFR CIGS/VSBYS THEN DEVELOP
EAST OF THE LARAMIE RANGE THIS AFTERNOON AND EVENING AS SNOW BECOMES
MORE WIDESPREAD. SOUTHERLY WINDS OF 10-15 KT WILL PREVAIL...WITH
PERHAPS SOME GUSTS ABOVE 20 KT POSSIBLE FOR THE PLAINS. WINDS WILL
SHIFT TO NORTHERLY AND BECOME RATHER GUSTY WITH THE PASSAGE OF A
STRONG COLD FRONT LATE TONIGHT.

&&

.FIRE WEATHER...
ISSUED AT 430 AM MST MON MAR 2 2015

NO FIRE WEATHER CONCERNS. SNOW IS EXPECTED TO DEVELOP TODAY AND
BECOME WIDESPREAD TONIGHT AND TUESDAY. SIGNIFICANT ACCUMULATIONS
ARE POSSIBLE...ESPECIALLY IN THE MOUNTAINS AND LOWER ELEVATION
AREAS WEST OF THE LARAMIE RANGE. THE SNOW WILL GRADUALLY DIMINISH
BY TUESDAY NIGHT. AN ARCTIC COLD FRONT WILL BRING BITTERLY COLD
TEMPERATURES AND DANGEROUS WIND CHILLS FROM TUESDAY NIGHT THROUGH
WEDNESDAY. MODERATING TEMPERATURES ARE EXPECTED LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR WYZ102-106>108-115>117.

     WINTER STORM WARNING FROM 3 PM THIS AFTERNOON TO 6 PM MST
     TUESDAY FOR WYZ101-103>105-109-110.

     WINTER STORM WARNING UNTIL 6 PM MST TUESDAY FOR WYZ111>114.

NE...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 6 PM MST
     TUESDAY FOR NEZ002-003-095-096.

&&

$$

SHORT TERM...CLH
LONG TERM...MJ
AVIATION...MJ
FIRE WEATHER...CLH




000
FXUS65 KRIW 020936
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
236 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../12Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
VFR CONDITIONS...FL SCT-BKN200-250 ACROSS THE SOUTH HALF OF
WY...WILL PREVAIL THROUGH 18Z.   A LOW PRESSURE SYSTEM LIFTING NE
ACROSS THE GREAT BASIN WILL PUSH SCT MVFR -SHRASN NORTH TO A VCNTY
KLND-KCPR LINE 21Z MON-00Z TUE.  CONDITIONS WILL THEN DETERIORATE
RAPIDLY AFTER 00Z TUE AS A COLD FRONT PUSHES DOWN FROM THE NORTH
BRINGING WIDESPREAD MVFR/IFR -SN AND MTN OBSCURATIONS ACROSS THE
AREA BY 4Z TUE.  THE HEAVIEST SNOWFALL AND AREAS OF LIFR CONDITIONS
WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE.  THESE CONDITIONS
WILL PERSIST THROUGH 12Z TUE.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
AN UPPER LEVEL DISTURBANCE WILL BRING AN INITIAL BAND OF MVFR/IFR
-SN NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80
11Z-15Z MON.  THERE SHOULD BE SOME IMPROVEMENT ACROSS THE SOUTH IN
THE LATE MORNING...AND THEN MORE WIDESPREAD PERSISTENT IFR SNOW IS
EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING AROUND 20Z MON AND
PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN COLD FRONT PUSHING
DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG THE DIVIDE MONDAY
EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD MVFR/IFR -SN BY
06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...AEM
FIRE WEATHER...BRANHAM









000
FXUS65 KRIW 020936
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
236 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT

FORECAST STILL ON TRACK FOR THE UPCOMING STORM SYSTEM TO IMPACT THE
AREA THROUGH TUESDAY EVENING. PRECIPITATION WILL BEGIN ACROSS
SOUTHERN SWEETWATER COUNTY THIS MORNING AND AFTERNOON...BUT
TEMPERATURES WILL BE TOO MILD TO PRODUCE MUCH IN THE WAY OF
HAZARDOUS CONDITIONS.

A CANADIAN COLD FRONT AND ASSOCIATED SNOWFALL WILL IMPACT NORTHERN
WYOMING THIS EVENING WITH PERIODS OF MODERATE SNOWFALL...STRONG
WIND...AND MUCH COLDER TEMPERATURES. THIS SYSTEM WILL QUICKLY MOVE
SOUTH THROUGH THE FORECAST AREA THROUGH THE EVENING HOURS. THE
SYSTEM WILL COMBINE WITH THE ALREADY OCCURRING PRECIPITATION ACROSS
SWEETWATER...SOUTHEASTERN FREMONT...AND NATRONA COUNTIES TO CREATE
WINTER STORM CONDITIONS WITH PERIODS OF HEAVY SNOWFALL AND GUSTY
WIND. WINTER STORM WARNINGS HAVE BEEN ISSUED FOR THESE AREAS FOR
THIS EVENING THROUGH WEDNESDAY AFTERNOON.

GENERAL BELIEF IS THAT THE FLOW IS NOT QUITE IDEAL FOR THE INCLUSION
OF THE LANDER FOOTHILLS IN THE WINTER STORM WARNING. THEIR EXPECTED
SNOWFALL AMOUNTS HAVE LEFT THEM TO BE INCLUDED IN THE WINTER WEATHER
ADVISORY...THOUGH IT IS POSSIBLE SOME AREAS IN THE LANDER FOOTHILLS
MAY VERY WELL SEE HIGHER AMOUNTS OF SNOWFALL. ALSO DECIDED TO
INCLUDE THE WESTERN SLOPES OF THE WIND RIVER MOUNTAINS IN THE
ADVISORY TO COVER THE FULL LENGTH OF HIGHWAY 28 THROUGH SOUTH PASS
WHERE WIND AND SNOWFALL WILL RESULT IN HAZARDOUS TRAVEL CONDITIONS
OVERNIGHT.

SNOWFALL STILL LOOKS TO TAPER OFF QUICKLY TUESDAY NIGHT WITH
BUILDING NORTHERLY FLOW. GENERALLY DRY CONDITIONS ANTICIPATED BY
LATE WEDNESDAY MORNING ACROSS THE FORECAST AREA. THE COLDER
TEMPERATURES ASSOCIATED WITH THIS SYSTEM WILL LINGER THROUGH
WEDNESDAY...WITH SINGLE DIGITS EXPECTED WEDNESDAY NIGHT.

.LONG TERM...THURSDAY THROUGH MONDAY

A RELATIVELY DRY NORTHWEST FLOW...AND A WARMING TREND TO SEASONAL
LEVELS WILL OCCUR LATE THIS WEEK...AND REMAIN IN PLACE THROUGH EARLY
NEXT WEEK. THE MAIN CAVEAT IS THE ECMWF STILL SHOWS A DISTINCT
SHORTWAVE TROUGH...AND ASSOCIATED WEAK COLD FRONT PUSHING SOUTHEAST
ACROSS THE AREA IN THE FRIDAY/SATURDAY TIME FRAME. HOWEVER...THE 00Z
GFS AND GEM ARE KEEPING THIS WAVE LESS AMPLIFIED AND FARTHER
NORTHEAST. WILL HAVE SOME SLIGHT MOUNTAIN POPS FOR THIS SYSTEM
FRIDAY AND SATURDAY...BUT IF MODELS TREND TOWARD THE ECMWF...POPS
WILL NEED TO BE EXPANDED AND INCREASED...MAINLY FRIDAY
NIGHT/SATURDAY.

&&

.AVIATION.../12Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
VFR CONDITIONS...FL SCT-BKN200-250 ACROSS THE SOUTH HALF OF
WY...WILL PREVAIL THROUGH 18Z.   A LOW PRESSURE SYSTEM LIFTING NE
ACROSS THE GREAT BASIN WILL PUSH SCT MVFR -SHRASN NORTH TO A VCNTY
KLND-KCPR LINE 21Z MON-00Z TUE.  CONDITIONS WILL THEN DETERIORATE
RAPIDLY AFTER 00Z TUE AS A COLD FRONT PUSHES DOWN FROM THE NORTH
BRINGING WIDESPREAD MVFR/IFR -SN AND MTN OBSCURATIONS ACROSS THE
AREA BY 4Z TUE.  THE HEAVIEST SNOWFALL AND AREAS OF LIFR CONDITIONS
WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE.  THESE CONDITIONS
WILL PERSIST THROUGH 12Z TUE.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
AN UPPER LEVEL DISTURBANCE WILL BRING AN INITIAL BAND OF MVFR/IFR
-SN NORTH INTO SOUTHERN WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80
11Z-15Z MON.  THERE SHOULD BE SOME IMPROVEMENT ACROSS THE SOUTH IN
THE LATE MORNING...AND THEN MORE WIDESPREAD PERSISTENT IFR SNOW IS
EXPECTED TO DEVELOP ACROSS SOUTHERN WYOMING AROUND 20Z MON AND
PERSIST INTO THE OVERNIGHT HOURS.  A CANADIAN COLD FRONT PUSHING
DOWN FROM THE NORTH WILL SPREAD SNOW SOUTH ALONG THE DIVIDE MONDAY
EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD MVFR/IFR -SN BY
06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.

&&

.FIRE WEATHER...

A WINTRY STORM SYSTEM IS STILL ON TRACK TO IMPACT THE FORECAST AREA
THIS EVENING AND THROUGH WEDNESDAY MORNING. MUCH OF THE AREA IS
ANTICIPATED TO EXPERIENCE LIGHT TO MODERATE SNOWFALL AMOUNTS...WITH
AREAS OF SOUTHWESTERN WYOMING EXPECTED TO SEE ENHANCED SNOWFALL. IN
ADDITION TO SNOWFALL...THE APPROACHING CANADIAN COLD FRONT WILL
BRING MUCH COLDER TEMPERATURES...AND PERIODS OF VERY STRONG WIND
THROUGH THE OVERNIGHT HOURS.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM 6 PM THIS EVENING TO 6 PM MST TUESDAY
WYZ019-020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 6 PM MST
TUESDAY WYZ002>011-014>018-028-029.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...AEM
FIRE WEATHER...BRANHAM








000
FXUS63 KUNR 020933
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
233 AM MST MON MAR 2 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT
ISSUED AT 224 AM MST MON MAR 2 2015

POTENT WINTER STORM SYSTEM TAKING SHAPE ACROSS THE
WESTERN CONUS AS A STRONG PAC NW IMPULSE WILL PARTIALLY MERGE WITH
AN EJECTING SW CONUS UPPER TROUGH. THIS WILL SET THE STAGE FOR
SNOW/WIND/AND ARCTIC AIR FOR THE REGION...WITH POTENTIALLY DANGEROUS
TRAVEL CONDS TUE MORNING ACROSS MUCH OF THE SD PLAINS. WEAK WAA
ONGOING ACROSS THE REGION AHEAD OF THE ADVANCING UPPER WAVES. LLJ
WILL INTENSIFY THIS MORNING...SUPPORTING GUSTY SOUTHERLY WINDS ON THE
SD PLAINS...ESP OVER SCENTRAL SOUTH DAKOTA. INCREASING CLOUDS
EXPECTED ACROSS THE SOUTHERN HALF...WHICH MAY HAMPER TEMP
POTENTIALS. HAVE SIDED ON THE COOL SIDE OF GUIDANCE FOR THIS...BUT
STILL A MUCH WARMER DAY THAN COMPARED TO THE PREVIOUS FEW. ATTENTION
TURNS TOWARD THE MERGING AFOREMENTIONED TROUGHS. LSA/UVM WILL
SPREAD OVER THE SW HALF OF THE FA THIS EVENING...WITH SNOW
DEVELOPING PER THE ADVANCING SOUTHERN STREAM SYSTEM. SNOW WILL
DEVELOP/OVERSPREAD THE SOUTHERN 2/3 AS FGEN/UPGLIDE PROCESSES ENSUE.
NEARLY ALL MODEL GUIDANCE SUGGEST A CONCENTRATED BAND OF HEAVIER
SNOWFALL ACROSS SCENTRAL SD. THE NAM REMAINS THE FURTHEST NW WITH
THE BAND PLACEMENT IN ADDITION TO BEING THE MOST AGGRESSIVE WITH
QPF. FEEL THE NW PLACEMENT IS POSSIBLE IF PHASING OF THE TWO UPPER
WAVES IS MORE COMPLETE...SUPPORTING A NW TILT TO THE HEIGHT FIELDS.
IN ADDITION...STRONG DYNAMICS COULD SUPPORT A PERIOD OF HEAVIER SNOW
MORE IN LINE WITH THE NAM. SOMETHING THE DAY SHIFT CAN ASSESS.
GENERALLY 2 TO 5 INCHES OF SNOW CAN BE EXPECTED ALONG AND SOUTH OF
I90...WITH HIGHEST AMOUNTS CONCENTRATED IN THE EXPECTED BAND ACROSS
SOUTHERN SD AND IN THE NORTHERN BLACK HILLS PER UPSLOPE. STEEP LL
LAPSE RATES/INCREASING LL FLOW/AND DEEPER INVERSION HEIGHTS WILL
SUPPORT A PERIOD OF STRONG UPSLOPE IN THE NORTHERN BLACK HILLS.
CURRENT THINKING IS WIDESPREAD 3 TO 5 WITH LOCALLY HIGHER AMOUNTS
EXPECTED. MEANWHILE THE STRONGER NW FLOW IMPULSE WILL QUICKLY SHIFT
SE INTO THE REGION...SUPPORTING A STRONG COLD FRONT INTO THE AREA.
STAUNCH PRESSURE RISES IN VERY STRONG CAA WILL SUPPORT INCREASING
NORTHERLY WINDS ON THE SD PLAINS...WITH WINDS INCREASING TO 20 TO 30
MPH WITH GUSTS IN THE 40S.  THIS WILL SUPPORT DANGEROUS TRAVEL CONDS
WHERE PERSISTENT SNOWFALL IS FORECAST. GIVEN ABOVE CONCERNS...HAVE
RETAINED THE WINTER STORM WATCH...DEFERRING HAZARD TYPE TO THE DAY
SHIFT WHEN A BETTER HANDLE ON SNOW AMOUNTS WILL BE ESTABLISHED. DID
PULL THE WATCH BACK TO THE EASTERN BH FOOTHILLS GIVEN CONCERNS ON
POTENTIALLY HIGHER SNOW AMOUNTS WITH WIND. OTHERWISE...ISSUED A
WINTER WX ADV FOR NE WY/THE BH/AND SW SD WHERE GENERALLY 2-5 INCHES
CAN BE EXPECTED. FURTHER NORTH ACROSS THE NW SD ZONES...MINIMAL SNOW
IS EXPECTED WITH WIND BEING THE PRIMARY HAZARD. A WIND ADV MAY BE
NEEDED THERE. SNOW WILL END TUE AFTERNOON AS AN ARCTIC HIGH BUILDS
INTO THE REGION. UPSLOPE SNOWS MAY LINGER INTO THE EVENING.
HOWEVER...DRYING BL CONDS WILL LIKELY SUPPORT A HEAVY WANE. A WEAK
UPSLOPE RESPONSE LOOKS POSSIBLE ONCE AGAIN LATE TUE NIGHT OVER THE
NORTHERN HILLS WITH THE MAIN UPPER WAVE PASSING OVERHEAD. HAVE
RETAINED LOW POPS FOR THIS. COLD CONDS EXPECTED TUE WITH TEMPS
FALLING THROUGH THE DAY INTO THE NIGHT...WITH SUBZERO CONDS ON TRACK
FOR TUE NIGHT...POTENTIALLY NECESSITATING THE NEED FOR WINDCHILL
HEADLINES.

.LONG TERM...WEDNESDAY THROUGH SUNDAY
ISSUED AT 224 AM MST MON MAR 2 2015

UPPER TROF AXIS SWINGS THROUGH THE NORTHERN PLAINS FOR WEDNESDAY AS
ARCTIC SURFACE HIGH SETTLES IN ACROSS THE DAKOTAS. DRY CONDITIONS
ARE EXPECTED WITH HIGH TEMPERATURES WELL BELOW AVERAGE...MAINLY IN
THE TEENS.

FOR THURSDAY THROUGH EARLY NEXT WEEK...GFS/ECMWF SHOWING UPPER TROF
SHIFTING QUICKLY EAST WITH FAST NORTHWEST FLOW ACROSS THE NORTHERN
PLAINS...AND RIDGING ACROSS THE FAR WESTERN CONUS. DRY CONDITIONS
EXPECTED THROUGH THE EXTENDED PERIOD WITH TEMPERATURES NEAR TO
SLIGHTLY ABOVE AVERAGE.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING
ISSUED AT 224 AM MST MON MAR 2 2015

VFR CONDITIONS ARE EXPECTED THROUGH MID AFTERNOON. A STRONG WEATHER
DISTURBANCE WILL MOVE INTO NORTHEAST WYOMING AND FAR SOUTHWEST SOUTH
DAKOTA LATE THIS AFTERNOON INTO THIS EVENING...WITH FLIGHT
CONDITIONS DETERIORATING QUICKLY TO IFR/LIFR IN SNOW BY MID EVENING
ACROSS MUCH OF THE AREA. A STRONG ARCTIC FRONT WILL DROP THROUGH THE
AREA THIS EVENING...INCREASING NORTH WINDS TO 25 TO 40 MPH WITH
HIGHER GUSTS THROUGH TUESDAY MORNING...PRODUCING AREAS OF NEAR ZERO
VISIBILITIES IN BLOWING SNOW.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 5 PM MST
     TUESDAY FOR SDZ024-025-027>029-041-072.

     WINTER STORM WATCH FROM THIS EVENING THROUGH TUESDAY AFTERNOON
     FOR SDZ026-030>032-042>044-046-047-049-073-074.

WY...WINTER WEATHER ADVISORY FROM 8 PM THIS EVENING TO 5 PM MST
     TUESDAY FOR WYZ054>058-071.

&&

$$

SHORT TERM...JC
LONG TERM...15
AVIATION...15







000
FXUS65 KRIW 020558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1057 PM MST SUN MAR 1 2015

UPDATE...UPDATED TO ADD 06Z AVIATION DISCUSSION BELOW.

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED AT 151 PM)

AFTER COLLABORATING WITH MID TERM FORECASTER...CYS AND WYDOT MET HAVE
DELAYED WATCH FOR SWEETWATER UNTIL 00Z TUESDAY.  ALL WINTER HIGHLIGHTS
NOW IN MID TERM PERIOD. SOME STRATUS AND FLURRIES WILL LINGER
AROUND THE VALLEYS AND BASINS TONIGHT.  WARMING WILL OCCUR MAINLY ACROSS
THE SOUTH WHERE MID TO UPPER 30S HIGHS WILL BE POSSIBLE MONDAY
WHERE SOME SNOW...RAIN MIXED WITH SNOW WILL INCREASE THROUGH THE
AFTERNOON. LEAST WARMING WILL BE IN THE NORTH. CLOUDS WILL SPREAD
UP FROM THE SOUTH WHILE THE NORTH AND CENTRAL AREAS AWAIT THE
CANADIAN BLAST OF COLD AIR SNOW AND WIND THAT WILL MOVE IN MONDAY EVENING.
PLEASE REFER TO CYSWSWRIW FOR MORE DETAILS ON THE IMPENDING
WEATHER CHANGE.

.MID TERM...MONDAY NIGHT THROUGH WEDNESDAY

THE PERIOD BEGINS WITH A CORNUCOPIA OF WINTRY CONDITIONS FOR THE
AREA. THE MAIN SHOW WILL FIRST BE SEEDED BY A SYSTEM THAT WILL
IMPACT MOSTLY AREAS TO OUR SOUTH DURING THE SHORT TERM PERIOD...BUT
IT WILL KICK UP A RICHLY MOIST AIRMASS FOR THIS TIME OF YEAR INTO
CENTRAL AND SOUTHERN WYOMING. THIS WILL GIVE OUR SECOND SYSTEM
SOMETHING TO WORK WITH AS IT DROPS SOUTH OUT OF THE DRY ARCTIC
MONDAY NIGHT. THIS SECOND SYSTEM WILL HAVE A LITTLE BIT OF SUPPORT
UPSTAIRS AS IT IS ACCOMPANIED BY A CYCLONICALLY CURVING JET AND SOME
ROBUST QG FORCING. ALSO THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY. HOWEVER...THE COMBINED
IMPACT OF THE SNOW...WIND...LOW WIND CHILLS AND EXPECTED AFFECTS ON
TRAVEL AND CALVING SEASON LEAD TO A LIBERAL ISSUANCE OF WINTER STORM
WATCHES AND ADVISORIES. MOST ELEMENTS WILL BE BORDERLINE BUT THE
COMBINED IMPACT CERTAINLY WARRANTS A HIGHLIGHT OF SOME SORT. WENT
AHEAD AND HIGHLIGHTED THE AREAS WHERE MORE SNOW IS EXPECTED WITH A
WATCH AND KEPT THE OTHERS AT AN ADVISORY. OPTED TO PUSH THE WATCH
FOR SWEETWATER FORWARD TO MONDAY TO HIGHLIGHT THE MORE SIGNIFICANT
IMPACT TO THE POPULATION CENTERS BUT THERE WILL CERTAINLY BE AT
LEAST SOME SNOW DURING THE DAY ON MONDAY FROM THE FIRST
SYSTEM...WHICH COULD BE HEAVY AT TIMES...ESPECIALLY SOUTH OF THE
INTERSTATE.

THINGS BEGIN TO WIND DOWN ON TUESDAY AFTERNOON AS IT CLEARS FROM
NORTH TO SOUTH...TUESDAY NIGHT COULD BE A COLD ONE WHEREVER IT DOES
CLEAR. THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO
MOVE IN HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND
PATCHY FOG EARLY WEDNESDAY MORNING.

.LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY

DRY NORTHWESTERLY FLOW...WITH A SFC HIGH OVER SOUTHERN WY...WILL
KEEP DRY CONDITIONS IN THE FORECAST TO END THE WORK WEEK. MAIN
FORECAST CHALLENGE WILL BE TEMPERATURES. TEMPS WILL REBOUND SLIGHTLY
FOR THURSDAY...HOWEVER...WITH FRESH SNOW STILL EXPECTED ON THE
GROUND...BELOW AVERAGE LOWS AND HIGHS CAN BE EXPECTED. TEMPS WILL
THEN MAKE A GRADUAL REBOUND THROUGH THE WEEKEND...WITH LOWS IN THE
TEENS AND 20S BY THE END OF THE WEEKEND...AND HIGHS IN THE 30S AND
40S.

STILL LOOKS TO BE ONLY ONE DISTURBANCE WORTH WATCHING FOR LATE IN
THE PERIOD. QUICK MOVING SHORTWAVE DROPS OUT OF CANADA FRIDAY NIGHT
INTO SATURDAY...WITH AN ENHANCED JET STREAK OF AROUND 75 KNOTS.
THIS DISTURBANCE WONT HAVE AN OVERLY ABUNDANT AMOUNT OF
MOISTURE...HOWEVER DEPENDING HOW THIS JET STREAK POSITIONS...AT LEAST
A FEW AREAS COULD SEE AREAS OF LIGHT SNOW...POSSIBLY MIXED WITH RAIN
AT TIMES. PLACED MAINLY SLIGHT CHANCE ACROSS AREAS WITH THE BEST
CHANCES FOR ANY PRECIP...WHICH AT THIS MOMENT APPEARS TO BE MAINLY
THE NORTHWESTERN MOUNTAINS...BIGHORN MOUNTAINS...AND THE LOWER
ELEVATIONS OF THE NORTHERN AND EASTERN CWA. THIS SHORTWAVE AND ITS
ASSOCIATED MOISTURE EXITS SATURDAY NIGHT...ALONG WITH ANY CHANCES
FOR PRECIP. NORTHWEST FLOW RETURNS ON SUNDAY...ALONG WITH A SLIGHT
WARMING TREND...POSSIBLY MAKING IT THE WARMEST DAY OF THE EXTENDED
FORECAST.

&&

.AVIATION.../06Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
VFR CONDITIONS...FL SCT-BKN200-250 ACROSS THE SOUTH HALF OF
WY...WILL PREVAIL THROUGH 18Z.   A LOW PRESSURE SYSTEM LIFTING NE
ACROSS THE GREAT BASIN WILL PUSH SCT MVFR -SHRASN NORTH TO A VCNTY
KLND-KCPR LINE 21Z MON-00Z TUE.  CONDITIONS WILL THEN DETERIORATE
RAPIDLY AFTER 00Z TUE AS A COLD FRONT PUSHES DOWN FROM THE NORTH
BRINGING WIDESPREAD MVFR/IFR -SN AND MTN OBSCURATIONS ACROSS THE
AREA BY 4Z TUE.  THE HEAVIEST SNOWFALL AND AREAS OF LIFR CONDITIONS
WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE.  THESE CONDITIONS
WILL PERSIST THROUGH 12Z TUE.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
AN UPPER LEVEL DISTURBANCE LIFTING ACROSS THE GREAT BASIN TONIGHT
WILL BRING AN INITIAL BAND OF MVFR/IFR -SN NORTH INTO SOUTHERN
WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 10Z-15Z MON.  THERE
SHOULD BE SOME IMPROVEMENT ACROSS THE SOUTH IN THE LATE
MORNING...AND THEN MORE WIDESPREAD PERSISTENT IFR SNOW IS EXPECTED
TO DEVELOP ACROSS SOUTHERN WYOMING AROUND 20Z MON AND PERSIST INTO
THE OVERNIGHT HOURS.  A CANADIAN COLD FRONT PUSHING DOWN FROM THE
NORTH WILL SPREAD SNOW SOUTH ALONG THE DIVIDE MONDAY
EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD MVFR/IFR -SN BY
06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.


&&

.FIRE WEATHER...

COLD AIR WILL REMAIN OVER THE NORTH AND CENTRAL AREAS...WHILE
TEMPERATURES WARM ACROSS THE FAR SOUTH WITH LIGHT SNOW...TO A RAIN
SNOW MIX MOVES INTO SOUTHEAST SWEETWATER COUNTY THROUGH THE
AFTERNOON. LOW MIXING HEIGHTS AND POOR SMOKE DISPERSAL WILL PREVAIL
ACROSS CENTRAL AND NORTH WITH FAIR TO LOCALLY GOOD SMOKE DISPERSAL WILL
OCCUR ACROSS THE SOUTH BEFORE THE ONSET OF LOWER CLOUDS AND
PRECIPITATION.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY AFTERNOON
WYZ018>020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM MONDAY TO 6 PM MST TUESDAY
WYZ002>011-015>017-028-029.

&&

$$

SHORT TERM...C.BAKER
MID TERM...ALLEN
LONG TERM...ANGLIN
AVIATION...AEM
FIRE WEATHER...C.BAKER














000
FXUS65 KRIW 020558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1057 PM MST SUN MAR 1 2015

UPDATE...UPDATED TO ADD 06Z AVIATION DISCUSSION BELOW.

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED AT 151 PM)

AFTER COLLABORATING WITH MID TERM FORECASTER...CYS AND WYDOT MET HAVE
DELAYED WATCH FOR SWEETWATER UNTIL 00Z TUESDAY.  ALL WINTER HIGHLIGHTS
NOW IN MID TERM PERIOD. SOME STRATUS AND FLURRIES WILL LINGER
AROUND THE VALLEYS AND BASINS TONIGHT.  WARMING WILL OCCUR MAINLY ACROSS
THE SOUTH WHERE MID TO UPPER 30S HIGHS WILL BE POSSIBLE MONDAY
WHERE SOME SNOW...RAIN MIXED WITH SNOW WILL INCREASE THROUGH THE
AFTERNOON. LEAST WARMING WILL BE IN THE NORTH. CLOUDS WILL SPREAD
UP FROM THE SOUTH WHILE THE NORTH AND CENTRAL AREAS AWAIT THE
CANADIAN BLAST OF COLD AIR SNOW AND WIND THAT WILL MOVE IN MONDAY EVENING.
PLEASE REFER TO CYSWSWRIW FOR MORE DETAILS ON THE IMPENDING
WEATHER CHANGE.

.MID TERM...MONDAY NIGHT THROUGH WEDNESDAY

THE PERIOD BEGINS WITH A CORNUCOPIA OF WINTRY CONDITIONS FOR THE
AREA. THE MAIN SHOW WILL FIRST BE SEEDED BY A SYSTEM THAT WILL
IMPACT MOSTLY AREAS TO OUR SOUTH DURING THE SHORT TERM PERIOD...BUT
IT WILL KICK UP A RICHLY MOIST AIRMASS FOR THIS TIME OF YEAR INTO
CENTRAL AND SOUTHERN WYOMING. THIS WILL GIVE OUR SECOND SYSTEM
SOMETHING TO WORK WITH AS IT DROPS SOUTH OUT OF THE DRY ARCTIC
MONDAY NIGHT. THIS SECOND SYSTEM WILL HAVE A LITTLE BIT OF SUPPORT
UPSTAIRS AS IT IS ACCOMPANIED BY A CYCLONICALLY CURVING JET AND SOME
ROBUST QG FORCING. ALSO THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY. HOWEVER...THE COMBINED
IMPACT OF THE SNOW...WIND...LOW WIND CHILLS AND EXPECTED AFFECTS ON
TRAVEL AND CALVING SEASON LEAD TO A LIBERAL ISSUANCE OF WINTER STORM
WATCHES AND ADVISORIES. MOST ELEMENTS WILL BE BORDERLINE BUT THE
COMBINED IMPACT CERTAINLY WARRANTS A HIGHLIGHT OF SOME SORT. WENT
AHEAD AND HIGHLIGHTED THE AREAS WHERE MORE SNOW IS EXPECTED WITH A
WATCH AND KEPT THE OTHERS AT AN ADVISORY. OPTED TO PUSH THE WATCH
FOR SWEETWATER FORWARD TO MONDAY TO HIGHLIGHT THE MORE SIGNIFICANT
IMPACT TO THE POPULATION CENTERS BUT THERE WILL CERTAINLY BE AT
LEAST SOME SNOW DURING THE DAY ON MONDAY FROM THE FIRST
SYSTEM...WHICH COULD BE HEAVY AT TIMES...ESPECIALLY SOUTH OF THE
INTERSTATE.

THINGS BEGIN TO WIND DOWN ON TUESDAY AFTERNOON AS IT CLEARS FROM
NORTH TO SOUTH...TUESDAY NIGHT COULD BE A COLD ONE WHEREVER IT DOES
CLEAR. THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO
MOVE IN HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND
PATCHY FOG EARLY WEDNESDAY MORNING.

.LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY

DRY NORTHWESTERLY FLOW...WITH A SFC HIGH OVER SOUTHERN WY...WILL
KEEP DRY CONDITIONS IN THE FORECAST TO END THE WORK WEEK. MAIN
FORECAST CHALLENGE WILL BE TEMPERATURES. TEMPS WILL REBOUND SLIGHTLY
FOR THURSDAY...HOWEVER...WITH FRESH SNOW STILL EXPECTED ON THE
GROUND...BELOW AVERAGE LOWS AND HIGHS CAN BE EXPECTED. TEMPS WILL
THEN MAKE A GRADUAL REBOUND THROUGH THE WEEKEND...WITH LOWS IN THE
TEENS AND 20S BY THE END OF THE WEEKEND...AND HIGHS IN THE 30S AND
40S.

STILL LOOKS TO BE ONLY ONE DISTURBANCE WORTH WATCHING FOR LATE IN
THE PERIOD. QUICK MOVING SHORTWAVE DROPS OUT OF CANADA FRIDAY NIGHT
INTO SATURDAY...WITH AN ENHANCED JET STREAK OF AROUND 75 KNOTS.
THIS DISTURBANCE WONT HAVE AN OVERLY ABUNDANT AMOUNT OF
MOISTURE...HOWEVER DEPENDING HOW THIS JET STREAK POSITIONS...AT LEAST
A FEW AREAS COULD SEE AREAS OF LIGHT SNOW...POSSIBLY MIXED WITH RAIN
AT TIMES. PLACED MAINLY SLIGHT CHANCE ACROSS AREAS WITH THE BEST
CHANCES FOR ANY PRECIP...WHICH AT THIS MOMENT APPEARS TO BE MAINLY
THE NORTHWESTERN MOUNTAINS...BIGHORN MOUNTAINS...AND THE LOWER
ELEVATIONS OF THE NORTHERN AND EASTERN CWA. THIS SHORTWAVE AND ITS
ASSOCIATED MOISTURE EXITS SATURDAY NIGHT...ALONG WITH ANY CHANCES
FOR PRECIP. NORTHWEST FLOW RETURNS ON SUNDAY...ALONG WITH A SLIGHT
WARMING TREND...POSSIBLY MAKING IT THE WARMEST DAY OF THE EXTENDED
FORECAST.

&&

.AVIATION.../06Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
VFR CONDITIONS...FL SCT-BKN200-250 ACROSS THE SOUTH HALF OF
WY...WILL PREVAIL THROUGH 18Z.   A LOW PRESSURE SYSTEM LIFTING NE
ACROSS THE GREAT BASIN WILL PUSH SCT MVFR -SHRASN NORTH TO A VCNTY
KLND-KCPR LINE 21Z MON-00Z TUE.  CONDITIONS WILL THEN DETERIORATE
RAPIDLY AFTER 00Z TUE AS A COLD FRONT PUSHES DOWN FROM THE NORTH
BRINGING WIDESPREAD MVFR/IFR -SN AND MTN OBSCURATIONS ACROSS THE
AREA BY 4Z TUE.  THE HEAVIEST SNOWFALL AND AREAS OF LIFR CONDITIONS
WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE.  THESE CONDITIONS
WILL PERSIST THROUGH 12Z TUE.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
AN UPPER LEVEL DISTURBANCE LIFTING ACROSS THE GREAT BASIN TONIGHT
WILL BRING AN INITIAL BAND OF MVFR/IFR -SN NORTH INTO SOUTHERN
WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 10Z-15Z MON.  THERE
SHOULD BE SOME IMPROVEMENT ACROSS THE SOUTH IN THE LATE
MORNING...AND THEN MORE WIDESPREAD PERSISTENT IFR SNOW IS EXPECTED
TO DEVELOP ACROSS SOUTHERN WYOMING AROUND 20Z MON AND PERSIST INTO
THE OVERNIGHT HOURS.  A CANADIAN COLD FRONT PUSHING DOWN FROM THE
NORTH WILL SPREAD SNOW SOUTH ALONG THE DIVIDE MONDAY
EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD MVFR/IFR -SN BY
06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.


&&

.FIRE WEATHER...

COLD AIR WILL REMAIN OVER THE NORTH AND CENTRAL AREAS...WHILE
TEMPERATURES WARM ACROSS THE FAR SOUTH WITH LIGHT SNOW...TO A RAIN
SNOW MIX MOVES INTO SOUTHEAST SWEETWATER COUNTY THROUGH THE
AFTERNOON. LOW MIXING HEIGHTS AND POOR SMOKE DISPERSAL WILL PREVAIL
ACROSS CENTRAL AND NORTH WITH FAIR TO LOCALLY GOOD SMOKE DISPERSAL WILL
OCCUR ACROSS THE SOUTH BEFORE THE ONSET OF LOWER CLOUDS AND
PRECIPITATION.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY AFTERNOON
WYZ018>020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM MONDAY TO 6 PM MST TUESDAY
WYZ002>011-015>017-028-029.

&&

$$

SHORT TERM...C.BAKER
MID TERM...ALLEN
LONG TERM...ANGLIN
AVIATION...AEM
FIRE WEATHER...C.BAKER













000
FXUS65 KRIW 020558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1057 PM MST SUN MAR 1 2015

UPDATE...UPDATED TO ADD 06Z AVIATION DISCUSSION BELOW.

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED AT 151 PM)

AFTER COLLABORATING WITH MID TERM FORECASTER...CYS AND WYDOT MET HAVE
DELAYED WATCH FOR SWEETWATER UNTIL 00Z TUESDAY.  ALL WINTER HIGHLIGHTS
NOW IN MID TERM PERIOD. SOME STRATUS AND FLURRIES WILL LINGER
AROUND THE VALLEYS AND BASINS TONIGHT.  WARMING WILL OCCUR MAINLY ACROSS
THE SOUTH WHERE MID TO UPPER 30S HIGHS WILL BE POSSIBLE MONDAY
WHERE SOME SNOW...RAIN MIXED WITH SNOW WILL INCREASE THROUGH THE
AFTERNOON. LEAST WARMING WILL BE IN THE NORTH. CLOUDS WILL SPREAD
UP FROM THE SOUTH WHILE THE NORTH AND CENTRAL AREAS AWAIT THE
CANADIAN BLAST OF COLD AIR SNOW AND WIND THAT WILL MOVE IN MONDAY EVENING.
PLEASE REFER TO CYSWSWRIW FOR MORE DETAILS ON THE IMPENDING
WEATHER CHANGE.

.MID TERM...MONDAY NIGHT THROUGH WEDNESDAY

THE PERIOD BEGINS WITH A CORNUCOPIA OF WINTRY CONDITIONS FOR THE
AREA. THE MAIN SHOW WILL FIRST BE SEEDED BY A SYSTEM THAT WILL
IMPACT MOSTLY AREAS TO OUR SOUTH DURING THE SHORT TERM PERIOD...BUT
IT WILL KICK UP A RICHLY MOIST AIRMASS FOR THIS TIME OF YEAR INTO
CENTRAL AND SOUTHERN WYOMING. THIS WILL GIVE OUR SECOND SYSTEM
SOMETHING TO WORK WITH AS IT DROPS SOUTH OUT OF THE DRY ARCTIC
MONDAY NIGHT. THIS SECOND SYSTEM WILL HAVE A LITTLE BIT OF SUPPORT
UPSTAIRS AS IT IS ACCOMPANIED BY A CYCLONICALLY CURVING JET AND SOME
ROBUST QG FORCING. ALSO THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY. HOWEVER...THE COMBINED
IMPACT OF THE SNOW...WIND...LOW WIND CHILLS AND EXPECTED AFFECTS ON
TRAVEL AND CALVING SEASON LEAD TO A LIBERAL ISSUANCE OF WINTER STORM
WATCHES AND ADVISORIES. MOST ELEMENTS WILL BE BORDERLINE BUT THE
COMBINED IMPACT CERTAINLY WARRANTS A HIGHLIGHT OF SOME SORT. WENT
AHEAD AND HIGHLIGHTED THE AREAS WHERE MORE SNOW IS EXPECTED WITH A
WATCH AND KEPT THE OTHERS AT AN ADVISORY. OPTED TO PUSH THE WATCH
FOR SWEETWATER FORWARD TO MONDAY TO HIGHLIGHT THE MORE SIGNIFICANT
IMPACT TO THE POPULATION CENTERS BUT THERE WILL CERTAINLY BE AT
LEAST SOME SNOW DURING THE DAY ON MONDAY FROM THE FIRST
SYSTEM...WHICH COULD BE HEAVY AT TIMES...ESPECIALLY SOUTH OF THE
INTERSTATE.

THINGS BEGIN TO WIND DOWN ON TUESDAY AFTERNOON AS IT CLEARS FROM
NORTH TO SOUTH...TUESDAY NIGHT COULD BE A COLD ONE WHEREVER IT DOES
CLEAR. THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO
MOVE IN HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND
PATCHY FOG EARLY WEDNESDAY MORNING.

.LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY

DRY NORTHWESTERLY FLOW...WITH A SFC HIGH OVER SOUTHERN WY...WILL
KEEP DRY CONDITIONS IN THE FORECAST TO END THE WORK WEEK. MAIN
FORECAST CHALLENGE WILL BE TEMPERATURES. TEMPS WILL REBOUND SLIGHTLY
FOR THURSDAY...HOWEVER...WITH FRESH SNOW STILL EXPECTED ON THE
GROUND...BELOW AVERAGE LOWS AND HIGHS CAN BE EXPECTED. TEMPS WILL
THEN MAKE A GRADUAL REBOUND THROUGH THE WEEKEND...WITH LOWS IN THE
TEENS AND 20S BY THE END OF THE WEEKEND...AND HIGHS IN THE 30S AND
40S.

STILL LOOKS TO BE ONLY ONE DISTURBANCE WORTH WATCHING FOR LATE IN
THE PERIOD. QUICK MOVING SHORTWAVE DROPS OUT OF CANADA FRIDAY NIGHT
INTO SATURDAY...WITH AN ENHANCED JET STREAK OF AROUND 75 KNOTS.
THIS DISTURBANCE WONT HAVE AN OVERLY ABUNDANT AMOUNT OF
MOISTURE...HOWEVER DEPENDING HOW THIS JET STREAK POSITIONS...AT LEAST
A FEW AREAS COULD SEE AREAS OF LIGHT SNOW...POSSIBLY MIXED WITH RAIN
AT TIMES. PLACED MAINLY SLIGHT CHANCE ACROSS AREAS WITH THE BEST
CHANCES FOR ANY PRECIP...WHICH AT THIS MOMENT APPEARS TO BE MAINLY
THE NORTHWESTERN MOUNTAINS...BIGHORN MOUNTAINS...AND THE LOWER
ELEVATIONS OF THE NORTHERN AND EASTERN CWA. THIS SHORTWAVE AND ITS
ASSOCIATED MOISTURE EXITS SATURDAY NIGHT...ALONG WITH ANY CHANCES
FOR PRECIP. NORTHWEST FLOW RETURNS ON SUNDAY...ALONG WITH A SLIGHT
WARMING TREND...POSSIBLY MAKING IT THE WARMEST DAY OF THE EXTENDED
FORECAST.

&&

.AVIATION.../06Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
VFR CONDITIONS...FL SCT-BKN200-250 ACROSS THE SOUTH HALF OF
WY...WILL PREVAIL THROUGH 18Z.   A LOW PRESSURE SYSTEM LIFTING NE
ACROSS THE GREAT BASIN WILL PUSH SCT MVFR -SHRASN NORTH TO A VCNTY
KLND-KCPR LINE 21Z MON-00Z TUE.  CONDITIONS WILL THEN DETERIORATE
RAPIDLY AFTER 00Z TUE AS A COLD FRONT PUSHES DOWN FROM THE NORTH
BRINGING WIDESPREAD MVFR/IFR -SN AND MTN OBSCURATIONS ACROSS THE
AREA BY 4Z TUE.  THE HEAVIEST SNOWFALL AND AREAS OF LIFR CONDITIONS
WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE.  THESE CONDITIONS
WILL PERSIST THROUGH 12Z TUE.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
AN UPPER LEVEL DISTURBANCE LIFTING ACROSS THE GREAT BASIN TONIGHT
WILL BRING AN INITIAL BAND OF MVFR/IFR -SN NORTH INTO SOUTHERN
WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 10Z-15Z MON.  THERE
SHOULD BE SOME IMPROVEMENT ACROSS THE SOUTH IN THE LATE
MORNING...AND THEN MORE WIDESPREAD PERSISTENT IFR SNOW IS EXPECTED
TO DEVELOP ACROSS SOUTHERN WYOMING AROUND 20Z MON AND PERSIST INTO
THE OVERNIGHT HOURS.  A CANADIAN COLD FRONT PUSHING DOWN FROM THE
NORTH WILL SPREAD SNOW SOUTH ALONG THE DIVIDE MONDAY
EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD MVFR/IFR -SN BY
06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.


&&

.FIRE WEATHER...

COLD AIR WILL REMAIN OVER THE NORTH AND CENTRAL AREAS...WHILE
TEMPERATURES WARM ACROSS THE FAR SOUTH WITH LIGHT SNOW...TO A RAIN
SNOW MIX MOVES INTO SOUTHEAST SWEETWATER COUNTY THROUGH THE
AFTERNOON. LOW MIXING HEIGHTS AND POOR SMOKE DISPERSAL WILL PREVAIL
ACROSS CENTRAL AND NORTH WITH FAIR TO LOCALLY GOOD SMOKE DISPERSAL WILL
OCCUR ACROSS THE SOUTH BEFORE THE ONSET OF LOWER CLOUDS AND
PRECIPITATION.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY AFTERNOON
WYZ018>020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM MONDAY TO 6 PM MST TUESDAY
WYZ002>011-015>017-028-029.

&&

$$

SHORT TERM...C.BAKER
MID TERM...ALLEN
LONG TERM...ANGLIN
AVIATION...AEM
FIRE WEATHER...C.BAKER













000
FXUS65 KRIW 020558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1057 PM MST SUN MAR 1 2015

UPDATE...UPDATED TO ADD 06Z AVIATION DISCUSSION BELOW.

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED AT 151 PM)

AFTER COLLABORATING WITH MID TERM FORECASTER...CYS AND WYDOT MET HAVE
DELAYED WATCH FOR SWEETWATER UNTIL 00Z TUESDAY.  ALL WINTER HIGHLIGHTS
NOW IN MID TERM PERIOD. SOME STRATUS AND FLURRIES WILL LINGER
AROUND THE VALLEYS AND BASINS TONIGHT.  WARMING WILL OCCUR MAINLY ACROSS
THE SOUTH WHERE MID TO UPPER 30S HIGHS WILL BE POSSIBLE MONDAY
WHERE SOME SNOW...RAIN MIXED WITH SNOW WILL INCREASE THROUGH THE
AFTERNOON. LEAST WARMING WILL BE IN THE NORTH. CLOUDS WILL SPREAD
UP FROM THE SOUTH WHILE THE NORTH AND CENTRAL AREAS AWAIT THE
CANADIAN BLAST OF COLD AIR SNOW AND WIND THAT WILL MOVE IN MONDAY EVENING.
PLEASE REFER TO CYSWSWRIW FOR MORE DETAILS ON THE IMPENDING
WEATHER CHANGE.

.MID TERM...MONDAY NIGHT THROUGH WEDNESDAY

THE PERIOD BEGINS WITH A CORNUCOPIA OF WINTRY CONDITIONS FOR THE
AREA. THE MAIN SHOW WILL FIRST BE SEEDED BY A SYSTEM THAT WILL
IMPACT MOSTLY AREAS TO OUR SOUTH DURING THE SHORT TERM PERIOD...BUT
IT WILL KICK UP A RICHLY MOIST AIRMASS FOR THIS TIME OF YEAR INTO
CENTRAL AND SOUTHERN WYOMING. THIS WILL GIVE OUR SECOND SYSTEM
SOMETHING TO WORK WITH AS IT DROPS SOUTH OUT OF THE DRY ARCTIC
MONDAY NIGHT. THIS SECOND SYSTEM WILL HAVE A LITTLE BIT OF SUPPORT
UPSTAIRS AS IT IS ACCOMPANIED BY A CYCLONICALLY CURVING JET AND SOME
ROBUST QG FORCING. ALSO THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY. HOWEVER...THE COMBINED
IMPACT OF THE SNOW...WIND...LOW WIND CHILLS AND EXPECTED AFFECTS ON
TRAVEL AND CALVING SEASON LEAD TO A LIBERAL ISSUANCE OF WINTER STORM
WATCHES AND ADVISORIES. MOST ELEMENTS WILL BE BORDERLINE BUT THE
COMBINED IMPACT CERTAINLY WARRANTS A HIGHLIGHT OF SOME SORT. WENT
AHEAD AND HIGHLIGHTED THE AREAS WHERE MORE SNOW IS EXPECTED WITH A
WATCH AND KEPT THE OTHERS AT AN ADVISORY. OPTED TO PUSH THE WATCH
FOR SWEETWATER FORWARD TO MONDAY TO HIGHLIGHT THE MORE SIGNIFICANT
IMPACT TO THE POPULATION CENTERS BUT THERE WILL CERTAINLY BE AT
LEAST SOME SNOW DURING THE DAY ON MONDAY FROM THE FIRST
SYSTEM...WHICH COULD BE HEAVY AT TIMES...ESPECIALLY SOUTH OF THE
INTERSTATE.

THINGS BEGIN TO WIND DOWN ON TUESDAY AFTERNOON AS IT CLEARS FROM
NORTH TO SOUTH...TUESDAY NIGHT COULD BE A COLD ONE WHEREVER IT DOES
CLEAR. THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO
MOVE IN HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND
PATCHY FOG EARLY WEDNESDAY MORNING.

.LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY

DRY NORTHWESTERLY FLOW...WITH A SFC HIGH OVER SOUTHERN WY...WILL
KEEP DRY CONDITIONS IN THE FORECAST TO END THE WORK WEEK. MAIN
FORECAST CHALLENGE WILL BE TEMPERATURES. TEMPS WILL REBOUND SLIGHTLY
FOR THURSDAY...HOWEVER...WITH FRESH SNOW STILL EXPECTED ON THE
GROUND...BELOW AVERAGE LOWS AND HIGHS CAN BE EXPECTED. TEMPS WILL
THEN MAKE A GRADUAL REBOUND THROUGH THE WEEKEND...WITH LOWS IN THE
TEENS AND 20S BY THE END OF THE WEEKEND...AND HIGHS IN THE 30S AND
40S.

STILL LOOKS TO BE ONLY ONE DISTURBANCE WORTH WATCHING FOR LATE IN
THE PERIOD. QUICK MOVING SHORTWAVE DROPS OUT OF CANADA FRIDAY NIGHT
INTO SATURDAY...WITH AN ENHANCED JET STREAK OF AROUND 75 KNOTS.
THIS DISTURBANCE WONT HAVE AN OVERLY ABUNDANT AMOUNT OF
MOISTURE...HOWEVER DEPENDING HOW THIS JET STREAK POSITIONS...AT LEAST
A FEW AREAS COULD SEE AREAS OF LIGHT SNOW...POSSIBLY MIXED WITH RAIN
AT TIMES. PLACED MAINLY SLIGHT CHANCE ACROSS AREAS WITH THE BEST
CHANCES FOR ANY PRECIP...WHICH AT THIS MOMENT APPEARS TO BE MAINLY
THE NORTHWESTERN MOUNTAINS...BIGHORN MOUNTAINS...AND THE LOWER
ELEVATIONS OF THE NORTHERN AND EASTERN CWA. THIS SHORTWAVE AND ITS
ASSOCIATED MOISTURE EXITS SATURDAY NIGHT...ALONG WITH ANY CHANCES
FOR PRECIP. NORTHWEST FLOW RETURNS ON SUNDAY...ALONG WITH A SLIGHT
WARMING TREND...POSSIBLY MAKING IT THE WARMEST DAY OF THE EXTENDED
FORECAST.

&&

.AVIATION.../06Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
VFR CONDITIONS...FL SCT-BKN200-250 ACROSS THE SOUTH HALF OF
WY...WILL PREVAIL THROUGH 18Z.   A LOW PRESSURE SYSTEM LIFTING NE
ACROSS THE GREAT BASIN WILL PUSH SCT MVFR -SHRASN NORTH TO A VCNTY
KLND-KCPR LINE 21Z MON-00Z TUE.  CONDITIONS WILL THEN DETERIORATE
RAPIDLY AFTER 00Z TUE AS A COLD FRONT PUSHES DOWN FROM THE NORTH
BRINGING WIDESPREAD MVFR/IFR -SN AND MTN OBSCURATIONS ACROSS THE
AREA BY 4Z TUE.  THE HEAVIEST SNOWFALL AND AREAS OF LIFR CONDITIONS
WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE.  THESE CONDITIONS
WILL PERSIST THROUGH 12Z TUE.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
AN UPPER LEVEL DISTURBANCE LIFTING ACROSS THE GREAT BASIN TONIGHT
WILL BRING AN INITIAL BAND OF MVFR/IFR -SN NORTH INTO SOUTHERN
WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 10Z-15Z MON.  THERE
SHOULD BE SOME IMPROVEMENT ACROSS THE SOUTH IN THE LATE
MORNING...AND THEN MORE WIDESPREAD PERSISTENT IFR SNOW IS EXPECTED
TO DEVELOP ACROSS SOUTHERN WYOMING AROUND 20Z MON AND PERSIST INTO
THE OVERNIGHT HOURS.  A CANADIAN COLD FRONT PUSHING DOWN FROM THE
NORTH WILL SPREAD SNOW SOUTH ALONG THE DIVIDE MONDAY
EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD MVFR/IFR -SN BY
06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.


&&

.FIRE WEATHER...

COLD AIR WILL REMAIN OVER THE NORTH AND CENTRAL AREAS...WHILE
TEMPERATURES WARM ACROSS THE FAR SOUTH WITH LIGHT SNOW...TO A RAIN
SNOW MIX MOVES INTO SOUTHEAST SWEETWATER COUNTY THROUGH THE
AFTERNOON. LOW MIXING HEIGHTS AND POOR SMOKE DISPERSAL WILL PREVAIL
ACROSS CENTRAL AND NORTH WITH FAIR TO LOCALLY GOOD SMOKE DISPERSAL WILL
OCCUR ACROSS THE SOUTH BEFORE THE ONSET OF LOWER CLOUDS AND
PRECIPITATION.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY AFTERNOON
WYZ018>020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM MONDAY TO 6 PM MST TUESDAY
WYZ002>011-015>017-028-029.

&&

$$

SHORT TERM...C.BAKER
MID TERM...ALLEN
LONG TERM...ANGLIN
AVIATION...AEM
FIRE WEATHER...C.BAKER













000
FXUS65 KRIW 020558
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1057 PM MST SUN MAR 1 2015

UPDATE...UPDATED TO ADD 06Z AVIATION DISCUSSION BELOW.

.SHORT TERM...TONIGHT THROUGH MONDAY (ISSUED AT 151 PM)

AFTER COLLABORATING WITH MID TERM FORECASTER...CYS AND WYDOT MET HAVE
DELAYED WATCH FOR SWEETWATER UNTIL 00Z TUESDAY.  ALL WINTER HIGHLIGHTS
NOW IN MID TERM PERIOD. SOME STRATUS AND FLURRIES WILL LINGER
AROUND THE VALLEYS AND BASINS TONIGHT.  WARMING WILL OCCUR MAINLY ACROSS
THE SOUTH WHERE MID TO UPPER 30S HIGHS WILL BE POSSIBLE MONDAY
WHERE SOME SNOW...RAIN MIXED WITH SNOW WILL INCREASE THROUGH THE
AFTERNOON. LEAST WARMING WILL BE IN THE NORTH. CLOUDS WILL SPREAD
UP FROM THE SOUTH WHILE THE NORTH AND CENTRAL AREAS AWAIT THE
CANADIAN BLAST OF COLD AIR SNOW AND WIND THAT WILL MOVE IN MONDAY EVENING.
PLEASE REFER TO CYSWSWRIW FOR MORE DETAILS ON THE IMPENDING
WEATHER CHANGE.

.MID TERM...MONDAY NIGHT THROUGH WEDNESDAY

THE PERIOD BEGINS WITH A CORNUCOPIA OF WINTRY CONDITIONS FOR THE
AREA. THE MAIN SHOW WILL FIRST BE SEEDED BY A SYSTEM THAT WILL
IMPACT MOSTLY AREAS TO OUR SOUTH DURING THE SHORT TERM PERIOD...BUT
IT WILL KICK UP A RICHLY MOIST AIRMASS FOR THIS TIME OF YEAR INTO
CENTRAL AND SOUTHERN WYOMING. THIS WILL GIVE OUR SECOND SYSTEM
SOMETHING TO WORK WITH AS IT DROPS SOUTH OUT OF THE DRY ARCTIC
MONDAY NIGHT. THIS SECOND SYSTEM WILL HAVE A LITTLE BIT OF SUPPORT
UPSTAIRS AS IT IS ACCOMPANIED BY A CYCLONICALLY CURVING JET AND SOME
ROBUST QG FORCING. ALSO THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY. HOWEVER...THE COMBINED
IMPACT OF THE SNOW...WIND...LOW WIND CHILLS AND EXPECTED AFFECTS ON
TRAVEL AND CALVING SEASON LEAD TO A LIBERAL ISSUANCE OF WINTER STORM
WATCHES AND ADVISORIES. MOST ELEMENTS WILL BE BORDERLINE BUT THE
COMBINED IMPACT CERTAINLY WARRANTS A HIGHLIGHT OF SOME SORT. WENT
AHEAD AND HIGHLIGHTED THE AREAS WHERE MORE SNOW IS EXPECTED WITH A
WATCH AND KEPT THE OTHERS AT AN ADVISORY. OPTED TO PUSH THE WATCH
FOR SWEETWATER FORWARD TO MONDAY TO HIGHLIGHT THE MORE SIGNIFICANT
IMPACT TO THE POPULATION CENTERS BUT THERE WILL CERTAINLY BE AT
LEAST SOME SNOW DURING THE DAY ON MONDAY FROM THE FIRST
SYSTEM...WHICH COULD BE HEAVY AT TIMES...ESPECIALLY SOUTH OF THE
INTERSTATE.

THINGS BEGIN TO WIND DOWN ON TUESDAY AFTERNOON AS IT CLEARS FROM
NORTH TO SOUTH...TUESDAY NIGHT COULD BE A COLD ONE WHEREVER IT DOES
CLEAR. THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO
MOVE IN HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND
PATCHY FOG EARLY WEDNESDAY MORNING.

.LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY

DRY NORTHWESTERLY FLOW...WITH A SFC HIGH OVER SOUTHERN WY...WILL
KEEP DRY CONDITIONS IN THE FORECAST TO END THE WORK WEEK. MAIN
FORECAST CHALLENGE WILL BE TEMPERATURES. TEMPS WILL REBOUND SLIGHTLY
FOR THURSDAY...HOWEVER...WITH FRESH SNOW STILL EXPECTED ON THE
GROUND...BELOW AVERAGE LOWS AND HIGHS CAN BE EXPECTED. TEMPS WILL
THEN MAKE A GRADUAL REBOUND THROUGH THE WEEKEND...WITH LOWS IN THE
TEENS AND 20S BY THE END OF THE WEEKEND...AND HIGHS IN THE 30S AND
40S.

STILL LOOKS TO BE ONLY ONE DISTURBANCE WORTH WATCHING FOR LATE IN
THE PERIOD. QUICK MOVING SHORTWAVE DROPS OUT OF CANADA FRIDAY NIGHT
INTO SATURDAY...WITH AN ENHANCED JET STREAK OF AROUND 75 KNOTS.
THIS DISTURBANCE WONT HAVE AN OVERLY ABUNDANT AMOUNT OF
MOISTURE...HOWEVER DEPENDING HOW THIS JET STREAK POSITIONS...AT LEAST
A FEW AREAS COULD SEE AREAS OF LIGHT SNOW...POSSIBLY MIXED WITH RAIN
AT TIMES. PLACED MAINLY SLIGHT CHANCE ACROSS AREAS WITH THE BEST
CHANCES FOR ANY PRECIP...WHICH AT THIS MOMENT APPEARS TO BE MAINLY
THE NORTHWESTERN MOUNTAINS...BIGHORN MOUNTAINS...AND THE LOWER
ELEVATIONS OF THE NORTHERN AND EASTERN CWA. THIS SHORTWAVE AND ITS
ASSOCIATED MOISTURE EXITS SATURDAY NIGHT...ALONG WITH ANY CHANCES
FOR PRECIP. NORTHWEST FLOW RETURNS ON SUNDAY...ALONG WITH A SLIGHT
WARMING TREND...POSSIBLY MAKING IT THE WARMEST DAY OF THE EXTENDED
FORECAST.

&&

.AVIATION.../06Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
VFR CONDITIONS...FL SCT-BKN200-250 ACROSS THE SOUTH HALF OF
WY...WILL PREVAIL THROUGH 18Z.   A LOW PRESSURE SYSTEM LIFTING NE
ACROSS THE GREAT BASIN WILL PUSH SCT MVFR -SHRASN NORTH TO A VCNTY
KLND-KCPR LINE 21Z MON-00Z TUE.  CONDITIONS WILL THEN DETERIORATE
RAPIDLY AFTER 00Z TUE AS A COLD FRONT PUSHES DOWN FROM THE NORTH
BRINGING WIDESPREAD MVFR/IFR -SN AND MTN OBSCURATIONS ACROSS THE
AREA BY 4Z TUE.  THE HEAVIEST SNOWFALL AND AREAS OF LIFR CONDITIONS
WILL BE FOUND VCNTY AND SOUTH OF A KCPR-KLND LINE.  THESE CONDITIONS
WILL PERSIST THROUGH 12Z TUE.

WEST OF THE DIVIDE...KBPI/KJAC/KPNA/KRKS ROUTES
AN UPPER LEVEL DISTURBANCE LIFTING ACROSS THE GREAT BASIN TONIGHT
WILL BRING AN INITIAL BAND OF MVFR/IFR -SN NORTH INTO SOUTHERN
WYOMING TO VCNTY AND SOUTH OF INTERSTATE 80 10Z-15Z MON.  THERE
SHOULD BE SOME IMPROVEMENT ACROSS THE SOUTH IN THE LATE
MORNING...AND THEN MORE WIDESPREAD PERSISTENT IFR SNOW IS EXPECTED
TO DEVELOP ACROSS SOUTHERN WYOMING AROUND 20Z MON AND PERSIST INTO
THE OVERNIGHT HOURS.  A CANADIAN COLD FRONT PUSHING DOWN FROM THE
NORTH WILL SPREAD SNOW SOUTH ALONG THE DIVIDE MONDAY
EVENING...FILLING WESTERN WYOMING WITH WIDESPREAD MVFR/IFR -SN BY
06Z TUES ALONG WITH MTNS BECOMING MOSTLY OBSCURED.


&&

.FIRE WEATHER...

COLD AIR WILL REMAIN OVER THE NORTH AND CENTRAL AREAS...WHILE
TEMPERATURES WARM ACROSS THE FAR SOUTH WITH LIGHT SNOW...TO A RAIN
SNOW MIX MOVES INTO SOUTHEAST SWEETWATER COUNTY THROUGH THE
AFTERNOON. LOW MIXING HEIGHTS AND POOR SMOKE DISPERSAL WILL PREVAIL
ACROSS CENTRAL AND NORTH WITH FAIR TO LOCALLY GOOD SMOKE DISPERSAL WILL
OCCUR ACROSS THE SOUTH BEFORE THE ONSET OF LOWER CLOUDS AND
PRECIPITATION.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY AFTERNOON
WYZ018>020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM MONDAY TO 6 PM MST TUESDAY
WYZ002>011-015>017-028-029.

&&

$$

SHORT TERM...C.BAKER
MID TERM...ALLEN
LONG TERM...ANGLIN
AVIATION...AEM
FIRE WEATHER...C.BAKER













000
FXUS63 KUNR 020433
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
933 PM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 912 PM MST SUN MAR 1 2015

MAIN REASON FOR UPDATING WAS TO ISSUE A WINTER STORM WATCH FOR SW
THROUGH SCNTRL SD LATE MON NIGHT THROUGH TUE MRNG. MODELS IN GOOD
AGREEMENT THAT A FEW INCHES OF SNOWFALL...PROBABLY 4 INCHES OR
LESS...WILL FALL ACROSS THAT AREA. MORE WORRISOME ARE THE GUSTY NW
WINDS EXPECTED THAT COULD PRODUCE A PERIOD OF NEAR WHITEOUT
CONDITIONS IN OPEN AREAS. CONTEMPLATED PUTTING RAPID CITY IN THE
WATCH BUT BELIEVE THERE WILL BE ENOUGH SHELTERING IN TOWN FROM
THE WORST CONDITIONS. THE CURRENT WATCH AREA MAY NEED TO BE
BORDERED WITH WINTER WX ADVISORIES ON THE WRN AND NRN EDGES. STAY
TUNED.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER WAVE IS SHIFTING OUT OF THE NORTHERN PLAINS WHILE CLOSED
LOW CONTINUES TO SPIN OVER CA. CUMULUS CLOUDS HAVE SPREAD
ACROSS THE CWA WITH SOME SNOW SHOWERS OVER PARTS OF SOUTHWEST
ND/SOUTHEAST MT. AT THE SURFACE...AN AREA OF HIGH PRESSURE
STRETCHES FROM CENTRAL MT INTO NE...AND A SOMEWHAT TIGHT PRESSURE
GRADIENT OVER SD IS KEEPING NORTHWEST WINDS BREEZY. TEMPS ARE
RISING INTO THE 20S AND LOWER 30S.

RETURN FLOW WILL DEVELOP TONIGHT AS HIGH PRESSURE SHIFTS
EASTWARD...AND WARM AIR WILL BEGIN TO ADVECT INTO THE AREA. UNDER
PARTLY CLOUDY SKIES...LOWS WILL BE 5 TO 15.

A WEAK UPPER RIDGE WILL BRIEFLY COVER THE CENTRAL STATES AS THE
TROUGH ASSOCIATED WITH A STRONG CANADIAN UPPER LOW BEGINS TO SWEEP
THE CALIFORNIAN LOW EASTWARD. SURFACE LOW PRESSURE PUSHES INTO THE
REGION AND PRESSURE GRADIENT TIGHTENS BETWEEN THAT AND THE EXITING
HIGH PRESSURE...PRODUCING SOME STRONG SOUTHERLY WINDS ACROSS SOUTH
CENTRAL SD AROUND MIDDAY MONDAY. WINDS AROUND 25 KTS WITH GUSTS OF
35 KTS ARE EXPECTED FOR A FEW HOURS BUT WILL QUICKLY DIMINISH MONDAY
AFTERNOON AS THE TROUGH AXIS MOVES THROUGH THE CWA. LOOKS LIKE ONLY
A MARGINAL WIND ADVISORY EVENT SO WILL HOLD OFF ISSUING HEADLINES
FOR NOW. HIGHS MONDAY WILL BE IN THE MID 30S TO MID 40S...WITH
CLOUDS INCREASING FROM THE SOUTH.

UPPER TROUGH WILL MOVE EASTWARD OVER THE ROCKIES AND COLD FRONT WILL
PUSH INTO THE REGION MONDAY EVENING. NORTHWEST WINDS WILL INCREASE
TO 20-30 KTS WITH HIGHER GUSTS BY TUESDAY MORNING...STRONGEST ACROSS
THE SD PLAINS...AND STRONG CAA WILL COMMENCE. SNOW WILL BEGIN MOVING
INTO NORTHEAST WY/SOUTHWEST SD BY MIDNIGHT AND SPREAD NORTHEASTWARD
AS THE NIGHT PROGRESSES. BEST FRONTOGENESIS CROSSES THE CWA BETWEEN
06Z AND 12Z. GENERALLY 1-3 INCHES OF SNOW IS EXPECTED BY 12Z TUESDAY
IN MOST PLACES...WITH LESSER AMOUNTS ACROSS NORTHWEST SD. STRONG
NORTHWEST WINDS WILL CREATE BLOWING SNOW AND REDUCED VISIBILITIES.
ALTHOUGH SNOW AMOUNTS WILL BE FAIRLY LIGHT...MAY NEED AN ADVISORY
LATER WITH BLOWING SNOW CONCERNS. FOR NOW WILL JUST EMPHASIZE THE
EVENT IN WXSTORY AND HWO. LOWS WILL RANGE FROM NEAR ZERO ACROSS THE
NORTHWESTERN CWA TO THE MID TEENS IN SOUTH CENTRAL SD.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER TROF LOCATED ACROSS THE DAKOTAS ON TUESDAY. LEADING SHORTWAVE
TRACKS INTO SOUTHERN MINNESOTA TUESDAY MORNING...WITH SECONDARY WAVE
DROPPING THROUGH THE WESTERN DAKOTAS LATE TUESDAY/TUESDAY NIGHT.
BEST ISENTROPIC LIFT/SNOWFALL ACCUMULATIONS WILL BE ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA TUESDAY MORNING. SOME MID LEVEL
DRYING WORKS INTO THE AREA TUESDAY AFTERNOON...BUT WITH STEEP LOW
LEVEL LAPSE RATES...-SHSN/FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON. GUSTY NORTHWEST WINDS...AIDED BY 5-7MB/3HR PRESSURE RISES
WILL CREATE SOME AREAS OF BLOWING SNOW. HIGH FROUDE/1-2KM RH
FAVORABLE FOR SOME UPSLOPE ENHANCEMENT. HOWEVER...SHORT DURATION OF
FAVORABLE CONDITIONS WILL LIMIT SNOWFALL AMOUNTS. ARCTIC HIGH
SETTLES IN ACROSS THE DAKOTAS FOR WEDNESDAY...HIGHS 20-25F BELOW
AVERAGE.

GFS/ECMWF HAVE BEEN TRENDING SLOWER WITH WARMUP FOR THE END OF THE
WEEK...WITH RIDGE A LITTLE FURTHER WEST. THIS KEEPS NORTHWEST FLOW
ACROSS THE FORECAST AREA...WITH WEAK COLD FRONT PASSAGE LATE
FRIDAY/EARLY SATURDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 912 PM MST SUN MAR 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH MONDAY AFTERNOON. A FAST
MOVING WINTER STORM WILL BRING RAPIDLY DETERIORATING CONDITIONS TO
PARTS OF NERN WY AND SWRN SD BY LATE MONDAY EVENING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
     FOR SDZ030>032-042>044-046-047-049.

WY...NONE.
&&

$$

UPDATE...JOHNSON
SHORT TERM...POJORLIE
LONG TERM...7
AVIATION...JOHNSON






000
FXUS63 KUNR 020433
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
933 PM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 912 PM MST SUN MAR 1 2015

MAIN REASON FOR UPDATING WAS TO ISSUE A WINTER STORM WATCH FOR SW
THROUGH SCNTRL SD LATE MON NIGHT THROUGH TUE MRNG. MODELS IN GOOD
AGREEMENT THAT A FEW INCHES OF SNOWFALL...PROBABLY 4 INCHES OR
LESS...WILL FALL ACROSS THAT AREA. MORE WORRISOME ARE THE GUSTY NW
WINDS EXPECTED THAT COULD PRODUCE A PERIOD OF NEAR WHITEOUT
CONDITIONS IN OPEN AREAS. CONTEMPLATED PUTTING RAPID CITY IN THE
WATCH BUT BELIEVE THERE WILL BE ENOUGH SHELTERING IN TOWN FROM
THE WORST CONDITIONS. THE CURRENT WATCH AREA MAY NEED TO BE
BORDERED WITH WINTER WX ADVISORIES ON THE WRN AND NRN EDGES. STAY
TUNED.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER WAVE IS SHIFTING OUT OF THE NORTHERN PLAINS WHILE CLOSED
LOW CONTINUES TO SPIN OVER CA. CUMULUS CLOUDS HAVE SPREAD
ACROSS THE CWA WITH SOME SNOW SHOWERS OVER PARTS OF SOUTHWEST
ND/SOUTHEAST MT. AT THE SURFACE...AN AREA OF HIGH PRESSURE
STRETCHES FROM CENTRAL MT INTO NE...AND A SOMEWHAT TIGHT PRESSURE
GRADIENT OVER SD IS KEEPING NORTHWEST WINDS BREEZY. TEMPS ARE
RISING INTO THE 20S AND LOWER 30S.

RETURN FLOW WILL DEVELOP TONIGHT AS HIGH PRESSURE SHIFTS
EASTWARD...AND WARM AIR WILL BEGIN TO ADVECT INTO THE AREA. UNDER
PARTLY CLOUDY SKIES...LOWS WILL BE 5 TO 15.

A WEAK UPPER RIDGE WILL BRIEFLY COVER THE CENTRAL STATES AS THE
TROUGH ASSOCIATED WITH A STRONG CANADIAN UPPER LOW BEGINS TO SWEEP
THE CALIFORNIAN LOW EASTWARD. SURFACE LOW PRESSURE PUSHES INTO THE
REGION AND PRESSURE GRADIENT TIGHTENS BETWEEN THAT AND THE EXITING
HIGH PRESSURE...PRODUCING SOME STRONG SOUTHERLY WINDS ACROSS SOUTH
CENTRAL SD AROUND MIDDAY MONDAY. WINDS AROUND 25 KTS WITH GUSTS OF
35 KTS ARE EXPECTED FOR A FEW HOURS BUT WILL QUICKLY DIMINISH MONDAY
AFTERNOON AS THE TROUGH AXIS MOVES THROUGH THE CWA. LOOKS LIKE ONLY
A MARGINAL WIND ADVISORY EVENT SO WILL HOLD OFF ISSUING HEADLINES
FOR NOW. HIGHS MONDAY WILL BE IN THE MID 30S TO MID 40S...WITH
CLOUDS INCREASING FROM THE SOUTH.

UPPER TROUGH WILL MOVE EASTWARD OVER THE ROCKIES AND COLD FRONT WILL
PUSH INTO THE REGION MONDAY EVENING. NORTHWEST WINDS WILL INCREASE
TO 20-30 KTS WITH HIGHER GUSTS BY TUESDAY MORNING...STRONGEST ACROSS
THE SD PLAINS...AND STRONG CAA WILL COMMENCE. SNOW WILL BEGIN MOVING
INTO NORTHEAST WY/SOUTHWEST SD BY MIDNIGHT AND SPREAD NORTHEASTWARD
AS THE NIGHT PROGRESSES. BEST FRONTOGENESIS CROSSES THE CWA BETWEEN
06Z AND 12Z. GENERALLY 1-3 INCHES OF SNOW IS EXPECTED BY 12Z TUESDAY
IN MOST PLACES...WITH LESSER AMOUNTS ACROSS NORTHWEST SD. STRONG
NORTHWEST WINDS WILL CREATE BLOWING SNOW AND REDUCED VISIBILITIES.
ALTHOUGH SNOW AMOUNTS WILL BE FAIRLY LIGHT...MAY NEED AN ADVISORY
LATER WITH BLOWING SNOW CONCERNS. FOR NOW WILL JUST EMPHASIZE THE
EVENT IN WXSTORY AND HWO. LOWS WILL RANGE FROM NEAR ZERO ACROSS THE
NORTHWESTERN CWA TO THE MID TEENS IN SOUTH CENTRAL SD.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER TROF LOCATED ACROSS THE DAKOTAS ON TUESDAY. LEADING SHORTWAVE
TRACKS INTO SOUTHERN MINNESOTA TUESDAY MORNING...WITH SECONDARY WAVE
DROPPING THROUGH THE WESTERN DAKOTAS LATE TUESDAY/TUESDAY NIGHT.
BEST ISENTROPIC LIFT/SNOWFALL ACCUMULATIONS WILL BE ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA TUESDAY MORNING. SOME MID LEVEL
DRYING WORKS INTO THE AREA TUESDAY AFTERNOON...BUT WITH STEEP LOW
LEVEL LAPSE RATES...-SHSN/FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON. GUSTY NORTHWEST WINDS...AIDED BY 5-7MB/3HR PRESSURE RISES
WILL CREATE SOME AREAS OF BLOWING SNOW. HIGH FROUDE/1-2KM RH
FAVORABLE FOR SOME UPSLOPE ENHANCEMENT. HOWEVER...SHORT DURATION OF
FAVORABLE CONDITIONS WILL LIMIT SNOWFALL AMOUNTS. ARCTIC HIGH
SETTLES IN ACROSS THE DAKOTAS FOR WEDNESDAY...HIGHS 20-25F BELOW
AVERAGE.

GFS/ECMWF HAVE BEEN TRENDING SLOWER WITH WARMUP FOR THE END OF THE
WEEK...WITH RIDGE A LITTLE FURTHER WEST. THIS KEEPS NORTHWEST FLOW
ACROSS THE FORECAST AREA...WITH WEAK COLD FRONT PASSAGE LATE
FRIDAY/EARLY SATURDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 912 PM MST SUN MAR 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH MONDAY AFTERNOON. A FAST
MOVING WINTER STORM WILL BRING RAPIDLY DETERIORATING CONDITIONS TO
PARTS OF NERN WY AND SWRN SD BY LATE MONDAY EVENING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
     FOR SDZ030>032-042>044-046-047-049.

WY...NONE.
&&

$$

UPDATE...JOHNSON
SHORT TERM...POJORLIE
LONG TERM...7
AVIATION...JOHNSON






000
FXUS63 KUNR 020433
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
933 PM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 912 PM MST SUN MAR 1 2015

MAIN REASON FOR UPDATING WAS TO ISSUE A WINTER STORM WATCH FOR SW
THROUGH SCNTRL SD LATE MON NIGHT THROUGH TUE MRNG. MODELS IN GOOD
AGREEMENT THAT A FEW INCHES OF SNOWFALL...PROBABLY 4 INCHES OR
LESS...WILL FALL ACROSS THAT AREA. MORE WORRISOME ARE THE GUSTY NW
WINDS EXPECTED THAT COULD PRODUCE A PERIOD OF NEAR WHITEOUT
CONDITIONS IN OPEN AREAS. CONTEMPLATED PUTTING RAPID CITY IN THE
WATCH BUT BELIEVE THERE WILL BE ENOUGH SHELTERING IN TOWN FROM
THE WORST CONDITIONS. THE CURRENT WATCH AREA MAY NEED TO BE
BORDERED WITH WINTER WX ADVISORIES ON THE WRN AND NRN EDGES. STAY
TUNED.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER WAVE IS SHIFTING OUT OF THE NORTHERN PLAINS WHILE CLOSED
LOW CONTINUES TO SPIN OVER CA. CUMULUS CLOUDS HAVE SPREAD
ACROSS THE CWA WITH SOME SNOW SHOWERS OVER PARTS OF SOUTHWEST
ND/SOUTHEAST MT. AT THE SURFACE...AN AREA OF HIGH PRESSURE
STRETCHES FROM CENTRAL MT INTO NE...AND A SOMEWHAT TIGHT PRESSURE
GRADIENT OVER SD IS KEEPING NORTHWEST WINDS BREEZY. TEMPS ARE
RISING INTO THE 20S AND LOWER 30S.

RETURN FLOW WILL DEVELOP TONIGHT AS HIGH PRESSURE SHIFTS
EASTWARD...AND WARM AIR WILL BEGIN TO ADVECT INTO THE AREA. UNDER
PARTLY CLOUDY SKIES...LOWS WILL BE 5 TO 15.

A WEAK UPPER RIDGE WILL BRIEFLY COVER THE CENTRAL STATES AS THE
TROUGH ASSOCIATED WITH A STRONG CANADIAN UPPER LOW BEGINS TO SWEEP
THE CALIFORNIAN LOW EASTWARD. SURFACE LOW PRESSURE PUSHES INTO THE
REGION AND PRESSURE GRADIENT TIGHTENS BETWEEN THAT AND THE EXITING
HIGH PRESSURE...PRODUCING SOME STRONG SOUTHERLY WINDS ACROSS SOUTH
CENTRAL SD AROUND MIDDAY MONDAY. WINDS AROUND 25 KTS WITH GUSTS OF
35 KTS ARE EXPECTED FOR A FEW HOURS BUT WILL QUICKLY DIMINISH MONDAY
AFTERNOON AS THE TROUGH AXIS MOVES THROUGH THE CWA. LOOKS LIKE ONLY
A MARGINAL WIND ADVISORY EVENT SO WILL HOLD OFF ISSUING HEADLINES
FOR NOW. HIGHS MONDAY WILL BE IN THE MID 30S TO MID 40S...WITH
CLOUDS INCREASING FROM THE SOUTH.

UPPER TROUGH WILL MOVE EASTWARD OVER THE ROCKIES AND COLD FRONT WILL
PUSH INTO THE REGION MONDAY EVENING. NORTHWEST WINDS WILL INCREASE
TO 20-30 KTS WITH HIGHER GUSTS BY TUESDAY MORNING...STRONGEST ACROSS
THE SD PLAINS...AND STRONG CAA WILL COMMENCE. SNOW WILL BEGIN MOVING
INTO NORTHEAST WY/SOUTHWEST SD BY MIDNIGHT AND SPREAD NORTHEASTWARD
AS THE NIGHT PROGRESSES. BEST FRONTOGENESIS CROSSES THE CWA BETWEEN
06Z AND 12Z. GENERALLY 1-3 INCHES OF SNOW IS EXPECTED BY 12Z TUESDAY
IN MOST PLACES...WITH LESSER AMOUNTS ACROSS NORTHWEST SD. STRONG
NORTHWEST WINDS WILL CREATE BLOWING SNOW AND REDUCED VISIBILITIES.
ALTHOUGH SNOW AMOUNTS WILL BE FAIRLY LIGHT...MAY NEED AN ADVISORY
LATER WITH BLOWING SNOW CONCERNS. FOR NOW WILL JUST EMPHASIZE THE
EVENT IN WXSTORY AND HWO. LOWS WILL RANGE FROM NEAR ZERO ACROSS THE
NORTHWESTERN CWA TO THE MID TEENS IN SOUTH CENTRAL SD.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER TROF LOCATED ACROSS THE DAKOTAS ON TUESDAY. LEADING SHORTWAVE
TRACKS INTO SOUTHERN MINNESOTA TUESDAY MORNING...WITH SECONDARY WAVE
DROPPING THROUGH THE WESTERN DAKOTAS LATE TUESDAY/TUESDAY NIGHT.
BEST ISENTROPIC LIFT/SNOWFALL ACCUMULATIONS WILL BE ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA TUESDAY MORNING. SOME MID LEVEL
DRYING WORKS INTO THE AREA TUESDAY AFTERNOON...BUT WITH STEEP LOW
LEVEL LAPSE RATES...-SHSN/FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON. GUSTY NORTHWEST WINDS...AIDED BY 5-7MB/3HR PRESSURE RISES
WILL CREATE SOME AREAS OF BLOWING SNOW. HIGH FROUDE/1-2KM RH
FAVORABLE FOR SOME UPSLOPE ENHANCEMENT. HOWEVER...SHORT DURATION OF
FAVORABLE CONDITIONS WILL LIMIT SNOWFALL AMOUNTS. ARCTIC HIGH
SETTLES IN ACROSS THE DAKOTAS FOR WEDNESDAY...HIGHS 20-25F BELOW
AVERAGE.

GFS/ECMWF HAVE BEEN TRENDING SLOWER WITH WARMUP FOR THE END OF THE
WEEK...WITH RIDGE A LITTLE FURTHER WEST. THIS KEEPS NORTHWEST FLOW
ACROSS THE FORECAST AREA...WITH WEAK COLD FRONT PASSAGE LATE
FRIDAY/EARLY SATURDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 912 PM MST SUN MAR 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH MONDAY AFTERNOON. A FAST
MOVING WINTER STORM WILL BRING RAPIDLY DETERIORATING CONDITIONS TO
PARTS OF NERN WY AND SWRN SD BY LATE MONDAY EVENING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
     FOR SDZ030>032-042>044-046-047-049.

WY...NONE.
&&

$$

UPDATE...JOHNSON
SHORT TERM...POJORLIE
LONG TERM...7
AVIATION...JOHNSON






000
FXUS63 KUNR 020433
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
933 PM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 912 PM MST SUN MAR 1 2015

MAIN REASON FOR UPDATING WAS TO ISSUE A WINTER STORM WATCH FOR SW
THROUGH SCNTRL SD LATE MON NIGHT THROUGH TUE MRNG. MODELS IN GOOD
AGREEMENT THAT A FEW INCHES OF SNOWFALL...PROBABLY 4 INCHES OR
LESS...WILL FALL ACROSS THAT AREA. MORE WORRISOME ARE THE GUSTY NW
WINDS EXPECTED THAT COULD PRODUCE A PERIOD OF NEAR WHITEOUT
CONDITIONS IN OPEN AREAS. CONTEMPLATED PUTTING RAPID CITY IN THE
WATCH BUT BELIEVE THERE WILL BE ENOUGH SHELTERING IN TOWN FROM
THE WORST CONDITIONS. THE CURRENT WATCH AREA MAY NEED TO BE
BORDERED WITH WINTER WX ADVISORIES ON THE WRN AND NRN EDGES. STAY
TUNED.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER WAVE IS SHIFTING OUT OF THE NORTHERN PLAINS WHILE CLOSED
LOW CONTINUES TO SPIN OVER CA. CUMULUS CLOUDS HAVE SPREAD
ACROSS THE CWA WITH SOME SNOW SHOWERS OVER PARTS OF SOUTHWEST
ND/SOUTHEAST MT. AT THE SURFACE...AN AREA OF HIGH PRESSURE
STRETCHES FROM CENTRAL MT INTO NE...AND A SOMEWHAT TIGHT PRESSURE
GRADIENT OVER SD IS KEEPING NORTHWEST WINDS BREEZY. TEMPS ARE
RISING INTO THE 20S AND LOWER 30S.

RETURN FLOW WILL DEVELOP TONIGHT AS HIGH PRESSURE SHIFTS
EASTWARD...AND WARM AIR WILL BEGIN TO ADVECT INTO THE AREA. UNDER
PARTLY CLOUDY SKIES...LOWS WILL BE 5 TO 15.

A WEAK UPPER RIDGE WILL BRIEFLY COVER THE CENTRAL STATES AS THE
TROUGH ASSOCIATED WITH A STRONG CANADIAN UPPER LOW BEGINS TO SWEEP
THE CALIFORNIAN LOW EASTWARD. SURFACE LOW PRESSURE PUSHES INTO THE
REGION AND PRESSURE GRADIENT TIGHTENS BETWEEN THAT AND THE EXITING
HIGH PRESSURE...PRODUCING SOME STRONG SOUTHERLY WINDS ACROSS SOUTH
CENTRAL SD AROUND MIDDAY MONDAY. WINDS AROUND 25 KTS WITH GUSTS OF
35 KTS ARE EXPECTED FOR A FEW HOURS BUT WILL QUICKLY DIMINISH MONDAY
AFTERNOON AS THE TROUGH AXIS MOVES THROUGH THE CWA. LOOKS LIKE ONLY
A MARGINAL WIND ADVISORY EVENT SO WILL HOLD OFF ISSUING HEADLINES
FOR NOW. HIGHS MONDAY WILL BE IN THE MID 30S TO MID 40S...WITH
CLOUDS INCREASING FROM THE SOUTH.

UPPER TROUGH WILL MOVE EASTWARD OVER THE ROCKIES AND COLD FRONT WILL
PUSH INTO THE REGION MONDAY EVENING. NORTHWEST WINDS WILL INCREASE
TO 20-30 KTS WITH HIGHER GUSTS BY TUESDAY MORNING...STRONGEST ACROSS
THE SD PLAINS...AND STRONG CAA WILL COMMENCE. SNOW WILL BEGIN MOVING
INTO NORTHEAST WY/SOUTHWEST SD BY MIDNIGHT AND SPREAD NORTHEASTWARD
AS THE NIGHT PROGRESSES. BEST FRONTOGENESIS CROSSES THE CWA BETWEEN
06Z AND 12Z. GENERALLY 1-3 INCHES OF SNOW IS EXPECTED BY 12Z TUESDAY
IN MOST PLACES...WITH LESSER AMOUNTS ACROSS NORTHWEST SD. STRONG
NORTHWEST WINDS WILL CREATE BLOWING SNOW AND REDUCED VISIBILITIES.
ALTHOUGH SNOW AMOUNTS WILL BE FAIRLY LIGHT...MAY NEED AN ADVISORY
LATER WITH BLOWING SNOW CONCERNS. FOR NOW WILL JUST EMPHASIZE THE
EVENT IN WXSTORY AND HWO. LOWS WILL RANGE FROM NEAR ZERO ACROSS THE
NORTHWESTERN CWA TO THE MID TEENS IN SOUTH CENTRAL SD.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER TROF LOCATED ACROSS THE DAKOTAS ON TUESDAY. LEADING SHORTWAVE
TRACKS INTO SOUTHERN MINNESOTA TUESDAY MORNING...WITH SECONDARY WAVE
DROPPING THROUGH THE WESTERN DAKOTAS LATE TUESDAY/TUESDAY NIGHT.
BEST ISENTROPIC LIFT/SNOWFALL ACCUMULATIONS WILL BE ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA TUESDAY MORNING. SOME MID LEVEL
DRYING WORKS INTO THE AREA TUESDAY AFTERNOON...BUT WITH STEEP LOW
LEVEL LAPSE RATES...-SHSN/FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON. GUSTY NORTHWEST WINDS...AIDED BY 5-7MB/3HR PRESSURE RISES
WILL CREATE SOME AREAS OF BLOWING SNOW. HIGH FROUDE/1-2KM RH
FAVORABLE FOR SOME UPSLOPE ENHANCEMENT. HOWEVER...SHORT DURATION OF
FAVORABLE CONDITIONS WILL LIMIT SNOWFALL AMOUNTS. ARCTIC HIGH
SETTLES IN ACROSS THE DAKOTAS FOR WEDNESDAY...HIGHS 20-25F BELOW
AVERAGE.

GFS/ECMWF HAVE BEEN TRENDING SLOWER WITH WARMUP FOR THE END OF THE
WEEK...WITH RIDGE A LITTLE FURTHER WEST. THIS KEEPS NORTHWEST FLOW
ACROSS THE FORECAST AREA...WITH WEAK COLD FRONT PASSAGE LATE
FRIDAY/EARLY SATURDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 912 PM MST SUN MAR 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH MONDAY AFTERNOON. A FAST
MOVING WINTER STORM WILL BRING RAPIDLY DETERIORATING CONDITIONS TO
PARTS OF NERN WY AND SWRN SD BY LATE MONDAY EVENING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
     FOR SDZ030>032-042>044-046-047-049.

WY...NONE.
&&

$$

UPDATE...JOHNSON
SHORT TERM...POJORLIE
LONG TERM...7
AVIATION...JOHNSON






000
FXUS63 KUNR 020433
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
933 PM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 912 PM MST SUN MAR 1 2015

MAIN REASON FOR UPDATING WAS TO ISSUE A WINTER STORM WATCH FOR SW
THROUGH SCNTRL SD LATE MON NIGHT THROUGH TUE MRNG. MODELS IN GOOD
AGREEMENT THAT A FEW INCHES OF SNOWFALL...PROBABLY 4 INCHES OR
LESS...WILL FALL ACROSS THAT AREA. MORE WORRISOME ARE THE GUSTY NW
WINDS EXPECTED THAT COULD PRODUCE A PERIOD OF NEAR WHITEOUT
CONDITIONS IN OPEN AREAS. CONTEMPLATED PUTTING RAPID CITY IN THE
WATCH BUT BELIEVE THERE WILL BE ENOUGH SHELTERING IN TOWN FROM
THE WORST CONDITIONS. THE CURRENT WATCH AREA MAY NEED TO BE
BORDERED WITH WINTER WX ADVISORIES ON THE WRN AND NRN EDGES. STAY
TUNED.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER WAVE IS SHIFTING OUT OF THE NORTHERN PLAINS WHILE CLOSED
LOW CONTINUES TO SPIN OVER CA. CUMULUS CLOUDS HAVE SPREAD
ACROSS THE CWA WITH SOME SNOW SHOWERS OVER PARTS OF SOUTHWEST
ND/SOUTHEAST MT. AT THE SURFACE...AN AREA OF HIGH PRESSURE
STRETCHES FROM CENTRAL MT INTO NE...AND A SOMEWHAT TIGHT PRESSURE
GRADIENT OVER SD IS KEEPING NORTHWEST WINDS BREEZY. TEMPS ARE
RISING INTO THE 20S AND LOWER 30S.

RETURN FLOW WILL DEVELOP TONIGHT AS HIGH PRESSURE SHIFTS
EASTWARD...AND WARM AIR WILL BEGIN TO ADVECT INTO THE AREA. UNDER
PARTLY CLOUDY SKIES...LOWS WILL BE 5 TO 15.

A WEAK UPPER RIDGE WILL BRIEFLY COVER THE CENTRAL STATES AS THE
TROUGH ASSOCIATED WITH A STRONG CANADIAN UPPER LOW BEGINS TO SWEEP
THE CALIFORNIAN LOW EASTWARD. SURFACE LOW PRESSURE PUSHES INTO THE
REGION AND PRESSURE GRADIENT TIGHTENS BETWEEN THAT AND THE EXITING
HIGH PRESSURE...PRODUCING SOME STRONG SOUTHERLY WINDS ACROSS SOUTH
CENTRAL SD AROUND MIDDAY MONDAY. WINDS AROUND 25 KTS WITH GUSTS OF
35 KTS ARE EXPECTED FOR A FEW HOURS BUT WILL QUICKLY DIMINISH MONDAY
AFTERNOON AS THE TROUGH AXIS MOVES THROUGH THE CWA. LOOKS LIKE ONLY
A MARGINAL WIND ADVISORY EVENT SO WILL HOLD OFF ISSUING HEADLINES
FOR NOW. HIGHS MONDAY WILL BE IN THE MID 30S TO MID 40S...WITH
CLOUDS INCREASING FROM THE SOUTH.

UPPER TROUGH WILL MOVE EASTWARD OVER THE ROCKIES AND COLD FRONT WILL
PUSH INTO THE REGION MONDAY EVENING. NORTHWEST WINDS WILL INCREASE
TO 20-30 KTS WITH HIGHER GUSTS BY TUESDAY MORNING...STRONGEST ACROSS
THE SD PLAINS...AND STRONG CAA WILL COMMENCE. SNOW WILL BEGIN MOVING
INTO NORTHEAST WY/SOUTHWEST SD BY MIDNIGHT AND SPREAD NORTHEASTWARD
AS THE NIGHT PROGRESSES. BEST FRONTOGENESIS CROSSES THE CWA BETWEEN
06Z AND 12Z. GENERALLY 1-3 INCHES OF SNOW IS EXPECTED BY 12Z TUESDAY
IN MOST PLACES...WITH LESSER AMOUNTS ACROSS NORTHWEST SD. STRONG
NORTHWEST WINDS WILL CREATE BLOWING SNOW AND REDUCED VISIBILITIES.
ALTHOUGH SNOW AMOUNTS WILL BE FAIRLY LIGHT...MAY NEED AN ADVISORY
LATER WITH BLOWING SNOW CONCERNS. FOR NOW WILL JUST EMPHASIZE THE
EVENT IN WXSTORY AND HWO. LOWS WILL RANGE FROM NEAR ZERO ACROSS THE
NORTHWESTERN CWA TO THE MID TEENS IN SOUTH CENTRAL SD.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER TROF LOCATED ACROSS THE DAKOTAS ON TUESDAY. LEADING SHORTWAVE
TRACKS INTO SOUTHERN MINNESOTA TUESDAY MORNING...WITH SECONDARY WAVE
DROPPING THROUGH THE WESTERN DAKOTAS LATE TUESDAY/TUESDAY NIGHT.
BEST ISENTROPIC LIFT/SNOWFALL ACCUMULATIONS WILL BE ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA TUESDAY MORNING. SOME MID LEVEL
DRYING WORKS INTO THE AREA TUESDAY AFTERNOON...BUT WITH STEEP LOW
LEVEL LAPSE RATES...-SHSN/FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON. GUSTY NORTHWEST WINDS...AIDED BY 5-7MB/3HR PRESSURE RISES
WILL CREATE SOME AREAS OF BLOWING SNOW. HIGH FROUDE/1-2KM RH
FAVORABLE FOR SOME UPSLOPE ENHANCEMENT. HOWEVER...SHORT DURATION OF
FAVORABLE CONDITIONS WILL LIMIT SNOWFALL AMOUNTS. ARCTIC HIGH
SETTLES IN ACROSS THE DAKOTAS FOR WEDNESDAY...HIGHS 20-25F BELOW
AVERAGE.

GFS/ECMWF HAVE BEEN TRENDING SLOWER WITH WARMUP FOR THE END OF THE
WEEK...WITH RIDGE A LITTLE FURTHER WEST. THIS KEEPS NORTHWEST FLOW
ACROSS THE FORECAST AREA...WITH WEAK COLD FRONT PASSAGE LATE
FRIDAY/EARLY SATURDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 912 PM MST SUN MAR 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH MONDAY AFTERNOON. A FAST
MOVING WINTER STORM WILL BRING RAPIDLY DETERIORATING CONDITIONS TO
PARTS OF NERN WY AND SWRN SD BY LATE MONDAY EVENING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
     FOR SDZ030>032-042>044-046-047-049.

WY...NONE.
&&

$$

UPDATE...JOHNSON
SHORT TERM...POJORLIE
LONG TERM...7
AVIATION...JOHNSON







000
FXUS63 KUNR 020433
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
933 PM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 912 PM MST SUN MAR 1 2015

MAIN REASON FOR UPDATING WAS TO ISSUE A WINTER STORM WATCH FOR SW
THROUGH SCNTRL SD LATE MON NIGHT THROUGH TUE MRNG. MODELS IN GOOD
AGREEMENT THAT A FEW INCHES OF SNOWFALL...PROBABLY 4 INCHES OR
LESS...WILL FALL ACROSS THAT AREA. MORE WORRISOME ARE THE GUSTY NW
WINDS EXPECTED THAT COULD PRODUCE A PERIOD OF NEAR WHITEOUT
CONDITIONS IN OPEN AREAS. CONTEMPLATED PUTTING RAPID CITY IN THE
WATCH BUT BELIEVE THERE WILL BE ENOUGH SHELTERING IN TOWN FROM
THE WORST CONDITIONS. THE CURRENT WATCH AREA MAY NEED TO BE
BORDERED WITH WINTER WX ADVISORIES ON THE WRN AND NRN EDGES. STAY
TUNED.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER WAVE IS SHIFTING OUT OF THE NORTHERN PLAINS WHILE CLOSED
LOW CONTINUES TO SPIN OVER CA. CUMULUS CLOUDS HAVE SPREAD
ACROSS THE CWA WITH SOME SNOW SHOWERS OVER PARTS OF SOUTHWEST
ND/SOUTHEAST MT. AT THE SURFACE...AN AREA OF HIGH PRESSURE
STRETCHES FROM CENTRAL MT INTO NE...AND A SOMEWHAT TIGHT PRESSURE
GRADIENT OVER SD IS KEEPING NORTHWEST WINDS BREEZY. TEMPS ARE
RISING INTO THE 20S AND LOWER 30S.

RETURN FLOW WILL DEVELOP TONIGHT AS HIGH PRESSURE SHIFTS
EASTWARD...AND WARM AIR WILL BEGIN TO ADVECT INTO THE AREA. UNDER
PARTLY CLOUDY SKIES...LOWS WILL BE 5 TO 15.

A WEAK UPPER RIDGE WILL BRIEFLY COVER THE CENTRAL STATES AS THE
TROUGH ASSOCIATED WITH A STRONG CANADIAN UPPER LOW BEGINS TO SWEEP
THE CALIFORNIAN LOW EASTWARD. SURFACE LOW PRESSURE PUSHES INTO THE
REGION AND PRESSURE GRADIENT TIGHTENS BETWEEN THAT AND THE EXITING
HIGH PRESSURE...PRODUCING SOME STRONG SOUTHERLY WINDS ACROSS SOUTH
CENTRAL SD AROUND MIDDAY MONDAY. WINDS AROUND 25 KTS WITH GUSTS OF
35 KTS ARE EXPECTED FOR A FEW HOURS BUT WILL QUICKLY DIMINISH MONDAY
AFTERNOON AS THE TROUGH AXIS MOVES THROUGH THE CWA. LOOKS LIKE ONLY
A MARGINAL WIND ADVISORY EVENT SO WILL HOLD OFF ISSUING HEADLINES
FOR NOW. HIGHS MONDAY WILL BE IN THE MID 30S TO MID 40S...WITH
CLOUDS INCREASING FROM THE SOUTH.

UPPER TROUGH WILL MOVE EASTWARD OVER THE ROCKIES AND COLD FRONT WILL
PUSH INTO THE REGION MONDAY EVENING. NORTHWEST WINDS WILL INCREASE
TO 20-30 KTS WITH HIGHER GUSTS BY TUESDAY MORNING...STRONGEST ACROSS
THE SD PLAINS...AND STRONG CAA WILL COMMENCE. SNOW WILL BEGIN MOVING
INTO NORTHEAST WY/SOUTHWEST SD BY MIDNIGHT AND SPREAD NORTHEASTWARD
AS THE NIGHT PROGRESSES. BEST FRONTOGENESIS CROSSES THE CWA BETWEEN
06Z AND 12Z. GENERALLY 1-3 INCHES OF SNOW IS EXPECTED BY 12Z TUESDAY
IN MOST PLACES...WITH LESSER AMOUNTS ACROSS NORTHWEST SD. STRONG
NORTHWEST WINDS WILL CREATE BLOWING SNOW AND REDUCED VISIBILITIES.
ALTHOUGH SNOW AMOUNTS WILL BE FAIRLY LIGHT...MAY NEED AN ADVISORY
LATER WITH BLOWING SNOW CONCERNS. FOR NOW WILL JUST EMPHASIZE THE
EVENT IN WXSTORY AND HWO. LOWS WILL RANGE FROM NEAR ZERO ACROSS THE
NORTHWESTERN CWA TO THE MID TEENS IN SOUTH CENTRAL SD.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER TROF LOCATED ACROSS THE DAKOTAS ON TUESDAY. LEADING SHORTWAVE
TRACKS INTO SOUTHERN MINNESOTA TUESDAY MORNING...WITH SECONDARY WAVE
DROPPING THROUGH THE WESTERN DAKOTAS LATE TUESDAY/TUESDAY NIGHT.
BEST ISENTROPIC LIFT/SNOWFALL ACCUMULATIONS WILL BE ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA TUESDAY MORNING. SOME MID LEVEL
DRYING WORKS INTO THE AREA TUESDAY AFTERNOON...BUT WITH STEEP LOW
LEVEL LAPSE RATES...-SHSN/FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON. GUSTY NORTHWEST WINDS...AIDED BY 5-7MB/3HR PRESSURE RISES
WILL CREATE SOME AREAS OF BLOWING SNOW. HIGH FROUDE/1-2KM RH
FAVORABLE FOR SOME UPSLOPE ENHANCEMENT. HOWEVER...SHORT DURATION OF
FAVORABLE CONDITIONS WILL LIMIT SNOWFALL AMOUNTS. ARCTIC HIGH
SETTLES IN ACROSS THE DAKOTAS FOR WEDNESDAY...HIGHS 20-25F BELOW
AVERAGE.

GFS/ECMWF HAVE BEEN TRENDING SLOWER WITH WARMUP FOR THE END OF THE
WEEK...WITH RIDGE A LITTLE FURTHER WEST. THIS KEEPS NORTHWEST FLOW
ACROSS THE FORECAST AREA...WITH WEAK COLD FRONT PASSAGE LATE
FRIDAY/EARLY SATURDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 912 PM MST SUN MAR 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH MONDAY AFTERNOON. A FAST
MOVING WINTER STORM WILL BRING RAPIDLY DETERIORATING CONDITIONS TO
PARTS OF NERN WY AND SWRN SD BY LATE MONDAY EVENING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
     FOR SDZ030>032-042>044-046-047-049.

WY...NONE.
&&

$$

UPDATE...JOHNSON
SHORT TERM...POJORLIE
LONG TERM...7
AVIATION...JOHNSON







000
FXUS63 KUNR 020433
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
933 PM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 912 PM MST SUN MAR 1 2015

MAIN REASON FOR UPDATING WAS TO ISSUE A WINTER STORM WATCH FOR SW
THROUGH SCNTRL SD LATE MON NIGHT THROUGH TUE MRNG. MODELS IN GOOD
AGREEMENT THAT A FEW INCHES OF SNOWFALL...PROBABLY 4 INCHES OR
LESS...WILL FALL ACROSS THAT AREA. MORE WORRISOME ARE THE GUSTY NW
WINDS EXPECTED THAT COULD PRODUCE A PERIOD OF NEAR WHITEOUT
CONDITIONS IN OPEN AREAS. CONTEMPLATED PUTTING RAPID CITY IN THE
WATCH BUT BELIEVE THERE WILL BE ENOUGH SHELTERING IN TOWN FROM
THE WORST CONDITIONS. THE CURRENT WATCH AREA MAY NEED TO BE
BORDERED WITH WINTER WX ADVISORIES ON THE WRN AND NRN EDGES. STAY
TUNED.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER WAVE IS SHIFTING OUT OF THE NORTHERN PLAINS WHILE CLOSED
LOW CONTINUES TO SPIN OVER CA. CUMULUS CLOUDS HAVE SPREAD
ACROSS THE CWA WITH SOME SNOW SHOWERS OVER PARTS OF SOUTHWEST
ND/SOUTHEAST MT. AT THE SURFACE...AN AREA OF HIGH PRESSURE
STRETCHES FROM CENTRAL MT INTO NE...AND A SOMEWHAT TIGHT PRESSURE
GRADIENT OVER SD IS KEEPING NORTHWEST WINDS BREEZY. TEMPS ARE
RISING INTO THE 20S AND LOWER 30S.

RETURN FLOW WILL DEVELOP TONIGHT AS HIGH PRESSURE SHIFTS
EASTWARD...AND WARM AIR WILL BEGIN TO ADVECT INTO THE AREA. UNDER
PARTLY CLOUDY SKIES...LOWS WILL BE 5 TO 15.

A WEAK UPPER RIDGE WILL BRIEFLY COVER THE CENTRAL STATES AS THE
TROUGH ASSOCIATED WITH A STRONG CANADIAN UPPER LOW BEGINS TO SWEEP
THE CALIFORNIAN LOW EASTWARD. SURFACE LOW PRESSURE PUSHES INTO THE
REGION AND PRESSURE GRADIENT TIGHTENS BETWEEN THAT AND THE EXITING
HIGH PRESSURE...PRODUCING SOME STRONG SOUTHERLY WINDS ACROSS SOUTH
CENTRAL SD AROUND MIDDAY MONDAY. WINDS AROUND 25 KTS WITH GUSTS OF
35 KTS ARE EXPECTED FOR A FEW HOURS BUT WILL QUICKLY DIMINISH MONDAY
AFTERNOON AS THE TROUGH AXIS MOVES THROUGH THE CWA. LOOKS LIKE ONLY
A MARGINAL WIND ADVISORY EVENT SO WILL HOLD OFF ISSUING HEADLINES
FOR NOW. HIGHS MONDAY WILL BE IN THE MID 30S TO MID 40S...WITH
CLOUDS INCREASING FROM THE SOUTH.

UPPER TROUGH WILL MOVE EASTWARD OVER THE ROCKIES AND COLD FRONT WILL
PUSH INTO THE REGION MONDAY EVENING. NORTHWEST WINDS WILL INCREASE
TO 20-30 KTS WITH HIGHER GUSTS BY TUESDAY MORNING...STRONGEST ACROSS
THE SD PLAINS...AND STRONG CAA WILL COMMENCE. SNOW WILL BEGIN MOVING
INTO NORTHEAST WY/SOUTHWEST SD BY MIDNIGHT AND SPREAD NORTHEASTWARD
AS THE NIGHT PROGRESSES. BEST FRONTOGENESIS CROSSES THE CWA BETWEEN
06Z AND 12Z. GENERALLY 1-3 INCHES OF SNOW IS EXPECTED BY 12Z TUESDAY
IN MOST PLACES...WITH LESSER AMOUNTS ACROSS NORTHWEST SD. STRONG
NORTHWEST WINDS WILL CREATE BLOWING SNOW AND REDUCED VISIBILITIES.
ALTHOUGH SNOW AMOUNTS WILL BE FAIRLY LIGHT...MAY NEED AN ADVISORY
LATER WITH BLOWING SNOW CONCERNS. FOR NOW WILL JUST EMPHASIZE THE
EVENT IN WXSTORY AND HWO. LOWS WILL RANGE FROM NEAR ZERO ACROSS THE
NORTHWESTERN CWA TO THE MID TEENS IN SOUTH CENTRAL SD.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER TROF LOCATED ACROSS THE DAKOTAS ON TUESDAY. LEADING SHORTWAVE
TRACKS INTO SOUTHERN MINNESOTA TUESDAY MORNING...WITH SECONDARY WAVE
DROPPING THROUGH THE WESTERN DAKOTAS LATE TUESDAY/TUESDAY NIGHT.
BEST ISENTROPIC LIFT/SNOWFALL ACCUMULATIONS WILL BE ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA TUESDAY MORNING. SOME MID LEVEL
DRYING WORKS INTO THE AREA TUESDAY AFTERNOON...BUT WITH STEEP LOW
LEVEL LAPSE RATES...-SHSN/FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON. GUSTY NORTHWEST WINDS...AIDED BY 5-7MB/3HR PRESSURE RISES
WILL CREATE SOME AREAS OF BLOWING SNOW. HIGH FROUDE/1-2KM RH
FAVORABLE FOR SOME UPSLOPE ENHANCEMENT. HOWEVER...SHORT DURATION OF
FAVORABLE CONDITIONS WILL LIMIT SNOWFALL AMOUNTS. ARCTIC HIGH
SETTLES IN ACROSS THE DAKOTAS FOR WEDNESDAY...HIGHS 20-25F BELOW
AVERAGE.

GFS/ECMWF HAVE BEEN TRENDING SLOWER WITH WARMUP FOR THE END OF THE
WEEK...WITH RIDGE A LITTLE FURTHER WEST. THIS KEEPS NORTHWEST FLOW
ACROSS THE FORECAST AREA...WITH WEAK COLD FRONT PASSAGE LATE
FRIDAY/EARLY SATURDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 912 PM MST SUN MAR 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH MONDAY AFTERNOON. A FAST
MOVING WINTER STORM WILL BRING RAPIDLY DETERIORATING CONDITIONS TO
PARTS OF NERN WY AND SWRN SD BY LATE MONDAY EVENING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
     FOR SDZ030>032-042>044-046-047-049.

WY...NONE.
&&

$$

UPDATE...JOHNSON
SHORT TERM...POJORLIE
LONG TERM...7
AVIATION...JOHNSON







000
FXUS63 KUNR 020433
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
933 PM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 912 PM MST SUN MAR 1 2015

MAIN REASON FOR UPDATING WAS TO ISSUE A WINTER STORM WATCH FOR SW
THROUGH SCNTRL SD LATE MON NIGHT THROUGH TUE MRNG. MODELS IN GOOD
AGREEMENT THAT A FEW INCHES OF SNOWFALL...PROBABLY 4 INCHES OR
LESS...WILL FALL ACROSS THAT AREA. MORE WORRISOME ARE THE GUSTY NW
WINDS EXPECTED THAT COULD PRODUCE A PERIOD OF NEAR WHITEOUT
CONDITIONS IN OPEN AREAS. CONTEMPLATED PUTTING RAPID CITY IN THE
WATCH BUT BELIEVE THERE WILL BE ENOUGH SHELTERING IN TOWN FROM
THE WORST CONDITIONS. THE CURRENT WATCH AREA MAY NEED TO BE
BORDERED WITH WINTER WX ADVISORIES ON THE WRN AND NRN EDGES. STAY
TUNED.

&&

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER WAVE IS SHIFTING OUT OF THE NORTHERN PLAINS WHILE CLOSED
LOW CONTINUES TO SPIN OVER CA. CUMULUS CLOUDS HAVE SPREAD
ACROSS THE CWA WITH SOME SNOW SHOWERS OVER PARTS OF SOUTHWEST
ND/SOUTHEAST MT. AT THE SURFACE...AN AREA OF HIGH PRESSURE
STRETCHES FROM CENTRAL MT INTO NE...AND A SOMEWHAT TIGHT PRESSURE
GRADIENT OVER SD IS KEEPING NORTHWEST WINDS BREEZY. TEMPS ARE
RISING INTO THE 20S AND LOWER 30S.

RETURN FLOW WILL DEVELOP TONIGHT AS HIGH PRESSURE SHIFTS
EASTWARD...AND WARM AIR WILL BEGIN TO ADVECT INTO THE AREA. UNDER
PARTLY CLOUDY SKIES...LOWS WILL BE 5 TO 15.

A WEAK UPPER RIDGE WILL BRIEFLY COVER THE CENTRAL STATES AS THE
TROUGH ASSOCIATED WITH A STRONG CANADIAN UPPER LOW BEGINS TO SWEEP
THE CALIFORNIAN LOW EASTWARD. SURFACE LOW PRESSURE PUSHES INTO THE
REGION AND PRESSURE GRADIENT TIGHTENS BETWEEN THAT AND THE EXITING
HIGH PRESSURE...PRODUCING SOME STRONG SOUTHERLY WINDS ACROSS SOUTH
CENTRAL SD AROUND MIDDAY MONDAY. WINDS AROUND 25 KTS WITH GUSTS OF
35 KTS ARE EXPECTED FOR A FEW HOURS BUT WILL QUICKLY DIMINISH MONDAY
AFTERNOON AS THE TROUGH AXIS MOVES THROUGH THE CWA. LOOKS LIKE ONLY
A MARGINAL WIND ADVISORY EVENT SO WILL HOLD OFF ISSUING HEADLINES
FOR NOW. HIGHS MONDAY WILL BE IN THE MID 30S TO MID 40S...WITH
CLOUDS INCREASING FROM THE SOUTH.

UPPER TROUGH WILL MOVE EASTWARD OVER THE ROCKIES AND COLD FRONT WILL
PUSH INTO THE REGION MONDAY EVENING. NORTHWEST WINDS WILL INCREASE
TO 20-30 KTS WITH HIGHER GUSTS BY TUESDAY MORNING...STRONGEST ACROSS
THE SD PLAINS...AND STRONG CAA WILL COMMENCE. SNOW WILL BEGIN MOVING
INTO NORTHEAST WY/SOUTHWEST SD BY MIDNIGHT AND SPREAD NORTHEASTWARD
AS THE NIGHT PROGRESSES. BEST FRONTOGENESIS CROSSES THE CWA BETWEEN
06Z AND 12Z. GENERALLY 1-3 INCHES OF SNOW IS EXPECTED BY 12Z TUESDAY
IN MOST PLACES...WITH LESSER AMOUNTS ACROSS NORTHWEST SD. STRONG
NORTHWEST WINDS WILL CREATE BLOWING SNOW AND REDUCED VISIBILITIES.
ALTHOUGH SNOW AMOUNTS WILL BE FAIRLY LIGHT...MAY NEED AN ADVISORY
LATER WITH BLOWING SNOW CONCERNS. FOR NOW WILL JUST EMPHASIZE THE
EVENT IN WXSTORY AND HWO. LOWS WILL RANGE FROM NEAR ZERO ACROSS THE
NORTHWESTERN CWA TO THE MID TEENS IN SOUTH CENTRAL SD.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER TROF LOCATED ACROSS THE DAKOTAS ON TUESDAY. LEADING SHORTWAVE
TRACKS INTO SOUTHERN MINNESOTA TUESDAY MORNING...WITH SECONDARY WAVE
DROPPING THROUGH THE WESTERN DAKOTAS LATE TUESDAY/TUESDAY NIGHT.
BEST ISENTROPIC LIFT/SNOWFALL ACCUMULATIONS WILL BE ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA TUESDAY MORNING. SOME MID LEVEL
DRYING WORKS INTO THE AREA TUESDAY AFTERNOON...BUT WITH STEEP LOW
LEVEL LAPSE RATES...-SHSN/FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON. GUSTY NORTHWEST WINDS...AIDED BY 5-7MB/3HR PRESSURE RISES
WILL CREATE SOME AREAS OF BLOWING SNOW. HIGH FROUDE/1-2KM RH
FAVORABLE FOR SOME UPSLOPE ENHANCEMENT. HOWEVER...SHORT DURATION OF
FAVORABLE CONDITIONS WILL LIMIT SNOWFALL AMOUNTS. ARCTIC HIGH
SETTLES IN ACROSS THE DAKOTAS FOR WEDNESDAY...HIGHS 20-25F BELOW
AVERAGE.

GFS/ECMWF HAVE BEEN TRENDING SLOWER WITH WARMUP FOR THE END OF THE
WEEK...WITH RIDGE A LITTLE FURTHER WEST. THIS KEEPS NORTHWEST FLOW
ACROSS THE FORECAST AREA...WITH WEAK COLD FRONT PASSAGE LATE
FRIDAY/EARLY SATURDAY.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 912 PM MST SUN MAR 1 2015

VFR CONDITIONS ARE EXPECTED THROUGH MONDAY AFTERNOON. A FAST
MOVING WINTER STORM WILL BRING RAPIDLY DETERIORATING CONDITIONS TO
PARTS OF NERN WY AND SWRN SD BY LATE MONDAY EVENING.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY MORNING
     FOR SDZ030>032-042>044-046-047-049.

WY...NONE.
&&

$$

UPDATE...JOHNSON
SHORT TERM...POJORLIE
LONG TERM...7
AVIATION...JOHNSON







000
FXUS65 KCYS 012243
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
343 PM MST SUN MAR 1 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 343 PM MST SUN MAR 1 2015

MAIN FORECAST FOCUS IS ON SNOW CHANCES AND SNOW AMOUNTS MONDAY INTO
TUESDAY. UPGRADED THE WINTER STORM WATCH TO A WARNING FOR THE SNOWY
AND SIERRA MADRE RANGES STARTING EARLY MONDAY MORNING AND CONTINUING
THROUGH TUESDAY AFTERNOON. ALSO ISSUED A WINTER STORM WATCH FOR
NORTHERN CARBON COUNTY AND THE WESTERN FRINGES OF ALBANY COUNTY FOR
LATE MONDAY AFTERNOON THROUGH TUESDAY AFTERNOON.

BASED ON RADAR IMAGES AND SURFACE OBSERVATIONS SHOWING WIDESPREAD
PRECIPITATION OVER THE SOUTHWEST CONUS...FEEL CONFIDENT A LARGE
AMOUNT OF MID AND UPPER LEVEL MOISTURE WILL SPREAD ACROSS THE
FORECAST AREA TOMORROW INTO EARLY TUESDAY. WATER VAPOR ALSO SHOWING
THE STREAM OF PACIFIC MOISTURE LIFTING NORTHEASTWARD THROUGH BAJA
CALIFORNIA...A FAVORED TRACK FOR MOISTURE TO REACH THE CENTRAL
ROCKIES...AS THE MOISTURE BYPASSES THE BLOCKING SIERRA NEVADA
MOUNTAINS.

MAIN CONCERN IS THE ACTUALLY TRACK UPPER LEVEL ENERGY WHICH IS
CURRENTLY OVER CALIFORNIA WILL TAKE ONCE A KICKER SYSTEM DROPS SOUTH
ALONG THE PACIFIC COAST. MODELS ARE IN FAIRLY GOOD AGREEMENT
EJECTING THE UPPER LEVEL DISTURBANCE NORTHEAST INTO SOUTHCENTRAL
WYOMING MONDAY BEFORE TRACKING EAST INTO THE PLAINS MONDAY NIGHT.
SOUTHCENTRAL WYOMING IS WHEN A BULK OF THE SNOW WILL FALL ACROSS
THE AREA. FULLY EXPECTING WINTER WEATHER ADVISORIES TO BE HOISTED
EITHER TONIGHT OR EARLY TOMORROW FOR MUCH OF THE FORECAST AREA.

IN ADDITION TO THE SOUTHERN STREAM DISTURBANCE...AS STRONG ARCTIC
COLD FRONT WILL MOVE ACROSS THE AREA MONDAY NIGHT. SNOW WILL BRIEFLY
INTENSIFY AS THE FRONT MOVES ACROSS THE AREA. THE BIGGER CONCERN IS
GUSTY NORTHERLY WINDS WHICH WILL PRODUCE BLOWING AND DRIFTING
SNOW...AND WHEN COMBINED WITH FALLING SNOW WILL SIGNIFICANTLY
REDUCE VISIBILITIES ACROSS MUCH OF THE FORECAST AREA. ALSO WIND
CHILLS WILL PLUMMET LATE TUESDAY INTO TUESDAY NIGHT. MOST LIKELY
WIND CHILL ADVISORIES AND WARNING WILL BE NEEDED TUESDAY NIGHT
INTO WEDNESDAY MORNING.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 330 PM MST THU JAN 15 2015

WEATHER PATTERN TO BECOME MORE ACTIVE THIS WEEKEND AND INTO NEXT
WEEK. SHORTWAVE WILL EXIT THE AREA SATURDAY NIGHT WITH RIDGING
SUNDAY. TEMPERATURES WILL WARM NICELY SUNDAY WITH HIGHS WEATHER
PATTERN TO BECOME MORE ACTIVE THIS WEEKEND AND INTO NEXT WEEK.
SHORTWAVE WILL EXIT THE AREA SATURDAY NIGHT WITH RIDGING SUNDAY.
TEMPERATURES WILL WARM NICELY SUNDAY WITH HIGHS IN THE MID 40S TO
MID 50S EAST AND 30S WEST UNDER PARTLY CLOUDY SKIES. WINDS WILL
AGAIN BE A CONCERN SUNDAY MAINLY ACROSS THE WIND PRONE AREAS IN
SOUTHEAST WYOMING. GFS SHOWING A SOLID 50 TO 60 KTS OVER THESE AREAS
AT 18Z. DEPENDING ON WHICH WAY THE MODELS TREND...SOME OF THE
STRONGER WINDS COULD STRETCH FARTHER EAST...SUCH AS INTO CHEYENNE.

MORE SHORTWAVE ENERGY TO DIVE ACROSS THE AREA MONDAY. MINIMAL
SNOW ACCUMULATIONS A DECENT POSSIBILITY INTO THE MOUNTAINS MONDAY
WITH A FEW RAIN/SNOW SHOWERS INTO LOWER ELEVATIONS INCLUDING THE
PLAINS. NORTHWEST FLOW WILL REMAIN IN PLACE TUESDAY AND WEDNESDAY
WITH COOLER TEMPERATURES IN STORE ACROSS THE AREA. NOT LOOKING FOR
ANYTHING NEAR AS COLD AS A FEW WEEKS AGO...BUT CERTAINLY BELOW
NORMAL INTO MID AND LATE NEXT WEEK.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 320 PM MST SUN MAR 1 2015

LONG RANGE MODELS IN FAIRLY GOOD AGREEMENT INTO NEXT WEEKEND...BUT
WITH ONE SUBSTANTIAL DIFFERENCE LATE-FRIDAY/SATURDAY COMPARED TO
YESTERDAY.

SOME FLURRIES ARE POSSIBLE AS THE STORM SYSTEM EARLY IN THE WEEK EXITS
THE REGION TO OUR SOUTH. WEDNESDAY WILL BE THE COLDEST DAY OF THE
WEEK WITH HIGHS STRUGGLING TO REACH THE LOW TO MID TEENS. KEPT
HIGHS A FEW DEGREES ABOVE MOS...AND BELIEVE THAT WESTERLY WINDS
AND THE MARCH SUNSHINE WILL RESULT IN TEMPERATURES A FEW DEGREES
HIGHER THAN GUIDANCE. OTHERWISE...TEMPERATURES MAY BE STUCK IN THE
SINGLE DIGITS THROUGH THE AFTERNOON. EITHER WAY...A WARMING TREND
IS EXPECTED FOR THE REMAINDER OF THE WEEK AS THE STRONG EASTERN
PACIFIC RIDGE EXPANDS EASTWARD A BIT INTO THE CENTRAL AND SOUTHERN
ROCKY MOUNTAINS. DUE TO POTENTIAL SNOW COVER...DID KEEP
TEMPERATURES LOWER THAN MOS THROUGH THE WEEK. EXPECT HIGHS TO
RETURN TO THE 40S TO AROUND 50 BY FRIDAY AFTERNOON.

MODELS ARE NOW SHOWING A RETURN TO BELOW NORMAL TEMPERATURES FOR
NEXT WEEK AS A COLD FRONT QUICKLY DIVES SOUTHWARD FROM WESTERN
CANADA AS THE UPPER LEVEL TROUGH PUSHES THROUGH THE AREA ON
SATURDAY. HAD TO LOWER MAX TEMPERATURES SEVERAL DEGREES SINCE THE
GFS AND ECMWF ARE IN DECENT AGREEMENT...AS WELL AS THE LONG RANGE
ENSEMBLES. SOME LIGHT SNOW IS POSSIBLE BUT KEPT POP BELOW 15
PERCENT FOR NOW OUTSIDE OF THE MOUNTAINS.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 321 AM MST SUN MAR 1 2015

A WARM FRONT WILL SLOWLY MOVE NORTHWARD ACROSS THE AREA
TONIGHT...BRINGING ANOTHER ROUND OF SNOW TO AREAS ALONG I80. LOW
MVFR TO IFR CIGS/VSBYS ARE LIKELY AFTER 06Z TONIGHT FROM KLAR TO
POSSIBLY AS FAR EAST AS KSNY. WINDS WILL GENERALLY BE LIGHT
THROUGH THE TAF PERIOD BUT WILL INCREASE OUT OF THE SOUTH LATE
TONIGHT AND INTO EARLY MONDAY MORNING. SNOW WILL BRIEFLY END ALONG
AND EAST OF THE LARAMIE RANGE ON MONDAY BEFORE THE FRONT PUSHES
SOUTHWARD ONCE AGAIN MONDAY NIGHT. FURTHER WEST...A PROLONGED
PERIOD OF SNOW IS POSSIBLE AT KRWL WITH IFR OR LIFR CONDITIONS
BEGINNING EARLY MONDAY MORNING AND CONTINUING INTO TUESDAY.

&&

.FIRE WEATHER...
ISSUED AT 225 PM MST SUN MAR 1 2015

A LOW PRESSURE SYSTEM AND ASSOCIATED UPPER LEVEL TROUGH WILL
APPROACH FROM THE SOUTHWEST TONIGHT AND MONDAY...AND MOVE ACROSS
THE CENTRAL ROCKIES MONDAY NIGHT AND TUESDAY. SNOW WILL DEVELOP
TONIGHT ACROSS SOUTH CENTRAL WYOMING AND BECOME MORE WIDESPREAD
MONDAY AND MONDAY NIGHT. THE SNOW MAY BE HEAVY AT TIMES...
ESPECIALLY OVER THE HIGHER TERRAIN. THE SNOW WILL TAPER OFF
TUESDAY NIGHT. A ARCTIC COLD FRONT WILL PLUNGE SOUTH THROUGH THE
DISTRICT MONDAY NIGHT. BITTERLY COLD TEMPERATURES AND WIND CHILLS
WILL PREVAIL TUESDAY THROUGH WEDNESDAY BEFORE GRADUALLY MODERATING
TEMPERATURES LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WARNING FROM 5 AM MONDAY TO 6 PM MST TUESDAY FOR
     WYZ111>114.

     WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
     AFTERNOON FOR WYZ104-105-109-110.

NE...NONE.

&&

$$

SHORT TERM...SML
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...MAJ/SML



000
FXUS63 KUNR 012140
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
240 PM MST SUN MAR 1 2015

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER WAVE IS SHIFTING OUT OF THE NORTHERN PLAINS WHILE CLOSED
LOW CONTINUES TO SPIN OVER CA. CUMULUS CLOUDS HAVE SPREAD
ACROSS THE CWA WITH SOME SNOW SHOWERS OVER PARTS OF SOUTHWEST
ND/SOUTHEAST MT. AT THE SURFACE...AN AREA OF HIGH PRESSURE
STRETCHES FROM CENTRAL MT INTO NE...AND A SOMEWHAT TIGHT PRESSURE
GRADIENT OVER SD IS KEEPING NORTHWEST WINDS BREEZY. TEMPS ARE
RISING INTO THE 20S AND LOWER 30S.

RETURN FLOW WILL DEVELOP TONIGHT AS HIGH PRESSURE SHIFTS
EASTWARD...AND WARM AIR WILL BEGIN TO ADVECT INTO THE AREA. UNDER
PARTLY CLOUDY SKIES...LOWS WILL BE 5 TO 15.

A WEAK UPPER RIDGE WILL BRIEFLY COVER THE CENTRAL STATES AS THE
TROUGH ASSOCIATED WITH A STRONG CANADIAN UPPER LOW BEGINS TO SWEEP
THE CALIFORNIAN LOW EASTWARD. SURFACE LOW PRESSURE PUSHES INTO THE
REGION AND PRESSURE GRADIENT TIGHTENS BETWEEN THAT AND THE EXITING
HIGH PRESSURE...PRODUCING SOME STRONG SOUTHERLY WINDS ACROSS SOUTH
CENTRAL SD AROUND MIDDAY MONDAY. WINDS AROUND 25 KTS WITH GUSTS OF
35 KTS ARE EXPECTED FOR A FEW HOURS BUT WILL QUICKLY DIMINISH MONDAY
AFTERNOON AS THE TROUGH AXIS MOVES THROUGH THE CWA. LOOKS LIKE ONLY
A MARGINAL WIND ADVISORY EVENT SO WILL HOLD OFF ISSUING HEADLINES
FOR NOW. HIGHS MONDAY WILL BE IN THE MID 30S TO MID 40S...WITH
CLOUDS INCREASING FROM THE SOUTH.

UPPER TROUGH WILL MOVE EASTWARD OVER THE ROCKIES AND COLD FRONT WILL
PUSH INTO THE REGION MONDAY EVENING. NORTHWEST WINDS WILL INCREASE
TO 20-30 KTS WITH HIGHER GUSTS BY TUESDAY MORNING...STRONGEST ACROSS
THE SD PLAINS...AND STRONG CAA WILL COMMENCE. SNOW WILL BEGIN MOVING
INTO NORTHEAST WY/SOUTHWEST SD BY MIDNIGHT AND SPREAD NORTHEASTWARD
AS THE NIGHT PROGRESSES. BEST FRONTOGENESIS CROSSES THE CWA BETWEEN
06Z AND 12Z. GENERALLY 1-3 INCHES OF SNOW IS EXPECTED BY 12Z TUESDAY
IN MOST PLACES...WITH LESSER AMOUNTS ACROSS NORTHWEST SD. STRONG
NORTHWEST WINDS WILL CREATE BLOWING SNOW AND REDUCED VISIBILITIES.
ALTHOUGH SNOW AMOUNTS WILL BE FAIRLY LIGHT...MAY NEED AN ADVISORY
LATER WITH BLOWING SNOW CONCERNS. FOR NOW WILL JUST EMPHASIZE THE
EVENT IN WXSTORY AND HWO. LOWS WILL RANGE FROM NEAR ZERO ACROSS THE
NORTHWESTERN CWA TO THE MID TEENS IN SOUTH CENTRAL SD.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER TROF LOCATED ACROSS THE DAKOTAS ON TUESDAY. LEADING SHORTWAVE
TRACKS INTO SOUTHERN MINNESOTA TUESDAY MORNING...WITH SECONDARY WAVE
DROPPING THROUGH THE WESTERN DAKOTAS LATE TUESDAY/TUESDAY NIGHT.
BEST ISENTROPIC LIFT/SNOWFALL ACCUMULATIONS WILL BE ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA TUESDAY MORNING. SOME MID LEVEL
DRYING WORKS INTO THE AREA TUESDAY AFTERNOON...BUT WITH STEEP LOW
LEVEL LAPSE RATES...-SHSN/FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON. GUSTY NORTHWEST WINDS...AIDED BY 5-7MB/3HR PRESSURE RISES
WILL CREATE SOME AREAS OF BLOWING SNOW. HIGH FROUDE/1-2KM RH
FAVORABLE FOR SOME UPSLOPE ENHANCEMENT. HOWEVER...SHORT DURATION OF
FAVORABLE CONDITIONS WILL LIMIT SNOWFALL AMOUNTS. ARCTIC HIGH
SETTLES IN ACROSS THE DAKOTAS FOR WEDNESDAY...HIGHS 20-25F BELOW
AVERAGE.

GFS/ECMWF HAVE BEEN TRENDING SLOWER WITH WARMUP FOR THE END OF THE
WEEK...WITH RIDGE A LITTLE FURTHER WEST. THIS KEEPS NORTHWEST FLOW
ACROSS THE FORECAST AREA...WITH WEAK COLD FRONT PASSAGE LATE
FRIDAY/EARLY SATURDAY.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING
ISSUED AT 235 PM MST SUN MAR 1 2015

LCL MVFR CIGS WILL BE POSSIBLE ACROSS NORTHWEST SOUTH DAKOTA THROUGH
LATE AFTERNOON. OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH
MONDAY AFTERNOON.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...7
AVIATION...7







000
FXUS63 KUNR 012140
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
240 PM MST SUN MAR 1 2015

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER WAVE IS SHIFTING OUT OF THE NORTHERN PLAINS WHILE CLOSED
LOW CONTINUES TO SPIN OVER CA. CUMULUS CLOUDS HAVE SPREAD
ACROSS THE CWA WITH SOME SNOW SHOWERS OVER PARTS OF SOUTHWEST
ND/SOUTHEAST MT. AT THE SURFACE...AN AREA OF HIGH PRESSURE
STRETCHES FROM CENTRAL MT INTO NE...AND A SOMEWHAT TIGHT PRESSURE
GRADIENT OVER SD IS KEEPING NORTHWEST WINDS BREEZY. TEMPS ARE
RISING INTO THE 20S AND LOWER 30S.

RETURN FLOW WILL DEVELOP TONIGHT AS HIGH PRESSURE SHIFTS
EASTWARD...AND WARM AIR WILL BEGIN TO ADVECT INTO THE AREA. UNDER
PARTLY CLOUDY SKIES...LOWS WILL BE 5 TO 15.

A WEAK UPPER RIDGE WILL BRIEFLY COVER THE CENTRAL STATES AS THE
TROUGH ASSOCIATED WITH A STRONG CANADIAN UPPER LOW BEGINS TO SWEEP
THE CALIFORNIAN LOW EASTWARD. SURFACE LOW PRESSURE PUSHES INTO THE
REGION AND PRESSURE GRADIENT TIGHTENS BETWEEN THAT AND THE EXITING
HIGH PRESSURE...PRODUCING SOME STRONG SOUTHERLY WINDS ACROSS SOUTH
CENTRAL SD AROUND MIDDAY MONDAY. WINDS AROUND 25 KTS WITH GUSTS OF
35 KTS ARE EXPECTED FOR A FEW HOURS BUT WILL QUICKLY DIMINISH MONDAY
AFTERNOON AS THE TROUGH AXIS MOVES THROUGH THE CWA. LOOKS LIKE ONLY
A MARGINAL WIND ADVISORY EVENT SO WILL HOLD OFF ISSUING HEADLINES
FOR NOW. HIGHS MONDAY WILL BE IN THE MID 30S TO MID 40S...WITH
CLOUDS INCREASING FROM THE SOUTH.

UPPER TROUGH WILL MOVE EASTWARD OVER THE ROCKIES AND COLD FRONT WILL
PUSH INTO THE REGION MONDAY EVENING. NORTHWEST WINDS WILL INCREASE
TO 20-30 KTS WITH HIGHER GUSTS BY TUESDAY MORNING...STRONGEST ACROSS
THE SD PLAINS...AND STRONG CAA WILL COMMENCE. SNOW WILL BEGIN MOVING
INTO NORTHEAST WY/SOUTHWEST SD BY MIDNIGHT AND SPREAD NORTHEASTWARD
AS THE NIGHT PROGRESSES. BEST FRONTOGENESIS CROSSES THE CWA BETWEEN
06Z AND 12Z. GENERALLY 1-3 INCHES OF SNOW IS EXPECTED BY 12Z TUESDAY
IN MOST PLACES...WITH LESSER AMOUNTS ACROSS NORTHWEST SD. STRONG
NORTHWEST WINDS WILL CREATE BLOWING SNOW AND REDUCED VISIBILITIES.
ALTHOUGH SNOW AMOUNTS WILL BE FAIRLY LIGHT...MAY NEED AN ADVISORY
LATER WITH BLOWING SNOW CONCERNS. FOR NOW WILL JUST EMPHASIZE THE
EVENT IN WXSTORY AND HWO. LOWS WILL RANGE FROM NEAR ZERO ACROSS THE
NORTHWESTERN CWA TO THE MID TEENS IN SOUTH CENTRAL SD.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER TROF LOCATED ACROSS THE DAKOTAS ON TUESDAY. LEADING SHORTWAVE
TRACKS INTO SOUTHERN MINNESOTA TUESDAY MORNING...WITH SECONDARY WAVE
DROPPING THROUGH THE WESTERN DAKOTAS LATE TUESDAY/TUESDAY NIGHT.
BEST ISENTROPIC LIFT/SNOWFALL ACCUMULATIONS WILL BE ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA TUESDAY MORNING. SOME MID LEVEL
DRYING WORKS INTO THE AREA TUESDAY AFTERNOON...BUT WITH STEEP LOW
LEVEL LAPSE RATES...-SHSN/FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON. GUSTY NORTHWEST WINDS...AIDED BY 5-7MB/3HR PRESSURE RISES
WILL CREATE SOME AREAS OF BLOWING SNOW. HIGH FROUDE/1-2KM RH
FAVORABLE FOR SOME UPSLOPE ENHANCEMENT. HOWEVER...SHORT DURATION OF
FAVORABLE CONDITIONS WILL LIMIT SNOWFALL AMOUNTS. ARCTIC HIGH
SETTLES IN ACROSS THE DAKOTAS FOR WEDNESDAY...HIGHS 20-25F BELOW
AVERAGE.

GFS/ECMWF HAVE BEEN TRENDING SLOWER WITH WARMUP FOR THE END OF THE
WEEK...WITH RIDGE A LITTLE FURTHER WEST. THIS KEEPS NORTHWEST FLOW
ACROSS THE FORECAST AREA...WITH WEAK COLD FRONT PASSAGE LATE
FRIDAY/EARLY SATURDAY.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING
ISSUED AT 235 PM MST SUN MAR 1 2015

LCL MVFR CIGS WILL BE POSSIBLE ACROSS NORTHWEST SOUTH DAKOTA THROUGH
LATE AFTERNOON. OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH
MONDAY AFTERNOON.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...7
AVIATION...7






000
FXUS63 KUNR 012140
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
240 PM MST SUN MAR 1 2015

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER WAVE IS SHIFTING OUT OF THE NORTHERN PLAINS WHILE CLOSED
LOW CONTINUES TO SPIN OVER CA. CUMULUS CLOUDS HAVE SPREAD
ACROSS THE CWA WITH SOME SNOW SHOWERS OVER PARTS OF SOUTHWEST
ND/SOUTHEAST MT. AT THE SURFACE...AN AREA OF HIGH PRESSURE
STRETCHES FROM CENTRAL MT INTO NE...AND A SOMEWHAT TIGHT PRESSURE
GRADIENT OVER SD IS KEEPING NORTHWEST WINDS BREEZY. TEMPS ARE
RISING INTO THE 20S AND LOWER 30S.

RETURN FLOW WILL DEVELOP TONIGHT AS HIGH PRESSURE SHIFTS
EASTWARD...AND WARM AIR WILL BEGIN TO ADVECT INTO THE AREA. UNDER
PARTLY CLOUDY SKIES...LOWS WILL BE 5 TO 15.

A WEAK UPPER RIDGE WILL BRIEFLY COVER THE CENTRAL STATES AS THE
TROUGH ASSOCIATED WITH A STRONG CANADIAN UPPER LOW BEGINS TO SWEEP
THE CALIFORNIAN LOW EASTWARD. SURFACE LOW PRESSURE PUSHES INTO THE
REGION AND PRESSURE GRADIENT TIGHTENS BETWEEN THAT AND THE EXITING
HIGH PRESSURE...PRODUCING SOME STRONG SOUTHERLY WINDS ACROSS SOUTH
CENTRAL SD AROUND MIDDAY MONDAY. WINDS AROUND 25 KTS WITH GUSTS OF
35 KTS ARE EXPECTED FOR A FEW HOURS BUT WILL QUICKLY DIMINISH MONDAY
AFTERNOON AS THE TROUGH AXIS MOVES THROUGH THE CWA. LOOKS LIKE ONLY
A MARGINAL WIND ADVISORY EVENT SO WILL HOLD OFF ISSUING HEADLINES
FOR NOW. HIGHS MONDAY WILL BE IN THE MID 30S TO MID 40S...WITH
CLOUDS INCREASING FROM THE SOUTH.

UPPER TROUGH WILL MOVE EASTWARD OVER THE ROCKIES AND COLD FRONT WILL
PUSH INTO THE REGION MONDAY EVENING. NORTHWEST WINDS WILL INCREASE
TO 20-30 KTS WITH HIGHER GUSTS BY TUESDAY MORNING...STRONGEST ACROSS
THE SD PLAINS...AND STRONG CAA WILL COMMENCE. SNOW WILL BEGIN MOVING
INTO NORTHEAST WY/SOUTHWEST SD BY MIDNIGHT AND SPREAD NORTHEASTWARD
AS THE NIGHT PROGRESSES. BEST FRONTOGENESIS CROSSES THE CWA BETWEEN
06Z AND 12Z. GENERALLY 1-3 INCHES OF SNOW IS EXPECTED BY 12Z TUESDAY
IN MOST PLACES...WITH LESSER AMOUNTS ACROSS NORTHWEST SD. STRONG
NORTHWEST WINDS WILL CREATE BLOWING SNOW AND REDUCED VISIBILITIES.
ALTHOUGH SNOW AMOUNTS WILL BE FAIRLY LIGHT...MAY NEED AN ADVISORY
LATER WITH BLOWING SNOW CONCERNS. FOR NOW WILL JUST EMPHASIZE THE
EVENT IN WXSTORY AND HWO. LOWS WILL RANGE FROM NEAR ZERO ACROSS THE
NORTHWESTERN CWA TO THE MID TEENS IN SOUTH CENTRAL SD.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER TROF LOCATED ACROSS THE DAKOTAS ON TUESDAY. LEADING SHORTWAVE
TRACKS INTO SOUTHERN MINNESOTA TUESDAY MORNING...WITH SECONDARY WAVE
DROPPING THROUGH THE WESTERN DAKOTAS LATE TUESDAY/TUESDAY NIGHT.
BEST ISENTROPIC LIFT/SNOWFALL ACCUMULATIONS WILL BE ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA TUESDAY MORNING. SOME MID LEVEL
DRYING WORKS INTO THE AREA TUESDAY AFTERNOON...BUT WITH STEEP LOW
LEVEL LAPSE RATES...-SHSN/FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON. GUSTY NORTHWEST WINDS...AIDED BY 5-7MB/3HR PRESSURE RISES
WILL CREATE SOME AREAS OF BLOWING SNOW. HIGH FROUDE/1-2KM RH
FAVORABLE FOR SOME UPSLOPE ENHANCEMENT. HOWEVER...SHORT DURATION OF
FAVORABLE CONDITIONS WILL LIMIT SNOWFALL AMOUNTS. ARCTIC HIGH
SETTLES IN ACROSS THE DAKOTAS FOR WEDNESDAY...HIGHS 20-25F BELOW
AVERAGE.

GFS/ECMWF HAVE BEEN TRENDING SLOWER WITH WARMUP FOR THE END OF THE
WEEK...WITH RIDGE A LITTLE FURTHER WEST. THIS KEEPS NORTHWEST FLOW
ACROSS THE FORECAST AREA...WITH WEAK COLD FRONT PASSAGE LATE
FRIDAY/EARLY SATURDAY.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING
ISSUED AT 235 PM MST SUN MAR 1 2015

LCL MVFR CIGS WILL BE POSSIBLE ACROSS NORTHWEST SOUTH DAKOTA THROUGH
LATE AFTERNOON. OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH
MONDAY AFTERNOON.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...7
AVIATION...7






000
FXUS63 KUNR 012140
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
240 PM MST SUN MAR 1 2015

.SHORT TERM...THIS EVENING THROUGH MONDAY NIGHT
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER WAVE IS SHIFTING OUT OF THE NORTHERN PLAINS WHILE CLOSED
LOW CONTINUES TO SPIN OVER CA. CUMULUS CLOUDS HAVE SPREAD
ACROSS THE CWA WITH SOME SNOW SHOWERS OVER PARTS OF SOUTHWEST
ND/SOUTHEAST MT. AT THE SURFACE...AN AREA OF HIGH PRESSURE
STRETCHES FROM CENTRAL MT INTO NE...AND A SOMEWHAT TIGHT PRESSURE
GRADIENT OVER SD IS KEEPING NORTHWEST WINDS BREEZY. TEMPS ARE
RISING INTO THE 20S AND LOWER 30S.

RETURN FLOW WILL DEVELOP TONIGHT AS HIGH PRESSURE SHIFTS
EASTWARD...AND WARM AIR WILL BEGIN TO ADVECT INTO THE AREA. UNDER
PARTLY CLOUDY SKIES...LOWS WILL BE 5 TO 15.

A WEAK UPPER RIDGE WILL BRIEFLY COVER THE CENTRAL STATES AS THE
TROUGH ASSOCIATED WITH A STRONG CANADIAN UPPER LOW BEGINS TO SWEEP
THE CALIFORNIAN LOW EASTWARD. SURFACE LOW PRESSURE PUSHES INTO THE
REGION AND PRESSURE GRADIENT TIGHTENS BETWEEN THAT AND THE EXITING
HIGH PRESSURE...PRODUCING SOME STRONG SOUTHERLY WINDS ACROSS SOUTH
CENTRAL SD AROUND MIDDAY MONDAY. WINDS AROUND 25 KTS WITH GUSTS OF
35 KTS ARE EXPECTED FOR A FEW HOURS BUT WILL QUICKLY DIMINISH MONDAY
AFTERNOON AS THE TROUGH AXIS MOVES THROUGH THE CWA. LOOKS LIKE ONLY
A MARGINAL WIND ADVISORY EVENT SO WILL HOLD OFF ISSUING HEADLINES
FOR NOW. HIGHS MONDAY WILL BE IN THE MID 30S TO MID 40S...WITH
CLOUDS INCREASING FROM THE SOUTH.

UPPER TROUGH WILL MOVE EASTWARD OVER THE ROCKIES AND COLD FRONT WILL
PUSH INTO THE REGION MONDAY EVENING. NORTHWEST WINDS WILL INCREASE
TO 20-30 KTS WITH HIGHER GUSTS BY TUESDAY MORNING...STRONGEST ACROSS
THE SD PLAINS...AND STRONG CAA WILL COMMENCE. SNOW WILL BEGIN MOVING
INTO NORTHEAST WY/SOUTHWEST SD BY MIDNIGHT AND SPREAD NORTHEASTWARD
AS THE NIGHT PROGRESSES. BEST FRONTOGENESIS CROSSES THE CWA BETWEEN
06Z AND 12Z. GENERALLY 1-3 INCHES OF SNOW IS EXPECTED BY 12Z TUESDAY
IN MOST PLACES...WITH LESSER AMOUNTS ACROSS NORTHWEST SD. STRONG
NORTHWEST WINDS WILL CREATE BLOWING SNOW AND REDUCED VISIBILITIES.
ALTHOUGH SNOW AMOUNTS WILL BE FAIRLY LIGHT...MAY NEED AN ADVISORY
LATER WITH BLOWING SNOW CONCERNS. FOR NOW WILL JUST EMPHASIZE THE
EVENT IN WXSTORY AND HWO. LOWS WILL RANGE FROM NEAR ZERO ACROSS THE
NORTHWESTERN CWA TO THE MID TEENS IN SOUTH CENTRAL SD.

.LONG TERM...TUESDAY THROUGH SUNDAY
ISSUED AT 235 PM MST SUN MAR 1 2015

UPPER TROF LOCATED ACROSS THE DAKOTAS ON TUESDAY. LEADING SHORTWAVE
TRACKS INTO SOUTHERN MINNESOTA TUESDAY MORNING...WITH SECONDARY WAVE
DROPPING THROUGH THE WESTERN DAKOTAS LATE TUESDAY/TUESDAY NIGHT.
BEST ISENTROPIC LIFT/SNOWFALL ACCUMULATIONS WILL BE ACROSS THE
SOUTHERN HALF OF THE FORECAST AREA TUESDAY MORNING. SOME MID LEVEL
DRYING WORKS INTO THE AREA TUESDAY AFTERNOON...BUT WITH STEEP LOW
LEVEL LAPSE RATES...-SHSN/FLURRIES WILL CONTINUE THROUGH THE
AFTERNOON. GUSTY NORTHWEST WINDS...AIDED BY 5-7MB/3HR PRESSURE RISES
WILL CREATE SOME AREAS OF BLOWING SNOW. HIGH FROUDE/1-2KM RH
FAVORABLE FOR SOME UPSLOPE ENHANCEMENT. HOWEVER...SHORT DURATION OF
FAVORABLE CONDITIONS WILL LIMIT SNOWFALL AMOUNTS. ARCTIC HIGH
SETTLES IN ACROSS THE DAKOTAS FOR WEDNESDAY...HIGHS 20-25F BELOW
AVERAGE.

GFS/ECMWF HAVE BEEN TRENDING SLOWER WITH WARMUP FOR THE END OF THE
WEEK...WITH RIDGE A LITTLE FURTHER WEST. THIS KEEPS NORTHWEST FLOW
ACROSS THE FORECAST AREA...WITH WEAK COLD FRONT PASSAGE LATE
FRIDAY/EARLY SATURDAY.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING
ISSUED AT 235 PM MST SUN MAR 1 2015

LCL MVFR CIGS WILL BE POSSIBLE ACROSS NORTHWEST SOUTH DAKOTA THROUGH
LATE AFTERNOON. OTHERWISE...VFR CONDITIONS ARE EXPECTED THROUGH
MONDAY AFTERNOON.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...7
AVIATION...7







000
FXUS65 KRIW 012051
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
151 PM MST SUN MAR 1 2015

.SHORT TERM...TONIGHT THROUGH MONDAY

AFTER COLLABORATING WITH MID TERM FORECASTER...CYS AND WYDOT MET HAVE
DELAYED WATCH FOR SWEETWATER UNTIL 00Z TUESDAY.  ALL WINTER HIGHLIGHTS
NOW IN MID TERM PERIOD. SOME STRATUS AND FLURRIES WILL LINGER
AROUND THE VALLEYS AND BASINS TONIGHT.  WARMING WILL OCCUR MAINLY ACROSS
THE SOUTH WHERE MID TO UPPER 30S HIGHS WILL BE POSSIBLE MONDAY
WHERE SOME SNOW...RAIN MIXED WITH SNOW WILL INCREASE THROUGH THE
AFTERNOON. LEAST WARMING WILL BE IN THE NORTH. CLOUDS WILL SPREAD
UP FROM THE SOUTH WHILE THE NORTH AND CENTRAL AREAS AWAIT THE
CANADIAN BLAST OF COLD AIR SNOW AND WIND THAT WILL MOVE IN MONDAY EVENING.
PLEASE REFER TO CYSWSWRIW FOR MORE DETAILS ON THE IMPENDING
WEATHER CHANGE.

.MID TERM...MONDAY NIGHT THROUGH WEDNESDAY

THE PERIOD BEGINS WITH A CORNUCOPIA OF WINTERY CONDITIONS FOR THE
AREA. THE MAIN SHOW WILL FIRST BE SEEDED BY A SYSTEM THAT WILL
IMPACT MOSTLY AREAS TO OUR SOUTH DURING THE SHORT TERM PERIOD...BUT
IT WILL KICK UP A RICHLY MOIST AIRMASS FOR THIS TIME OF YEAR INTO
CENTRAL AND SOUTHERN WYOMING. THIS WILL GIVE OUR SECOND SYSTEM
SOMETHING TO WORK WITH AS IT DROPS SOUTH OUT OF THE DRY ARCTIC
MONDAY NIGHT. THIS SECOND SYSTEM WILL HAVE A LITTLE BIT OF SUPPORT
UPSTAIRS AS IT IS ACCOMPANIED BY A CYCLONICALLY CURVING JET AND SOME
ROBUST QG FORCING. ALSO THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY. HOWEVER...THE COMBINED
IMPACT OF THE SNOW...WIND...LOW WIND CHILLS AND EXPECTED AFFECTS ON
TRAVEL AND CALVING SEASON LEAD TO A LIBERAL ISSUANCE OF WINTER STORM
WATCHES AND ADVISORIES. MOST ELEMENTS WILL BE BORDERLINE BUT THE
COMBINED IMPACT CERTAINLY WARRANTS A HIGHLIGHT OF SOME SORT. WENT
AHEAD AND HIGHLIGHTED THE AREAS WHERE MORE SNOW IS EXPECTED WITH A
WATCH AND KEPT THE OTHERS AT AN ADVISORY. OPTED TO PUSH THE WATCH
FOR SWEETWATER FORWARD TO MONDAY TO HIGHLIGHT THE MORE SIGNIFICANT
IMPACT TO THE POPULATION CENTERS BUT THERE WILL CERTAINLY BE AT
LEAST SOME SNOW DURING THE DAY ON MONDAY FROM THE FIRST
SYSTEM...WHICH COULD BE HEAVY AT TIMES...ESPECIALLY SOUTH OF THE
INTERSTATE.

THINGS BEGIN TO WIND DOWN ON TUESDAY AFTERNOON AS IT CLEARS FROM
NORTH TO SOUTH...TUESDAY NIGHT COULD BE A COLD ONE WHEREVER IT DOES
CLEAR. THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO
MOVE IN HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND
PATCHY FOG EARLY WEDNESDAY MORNING.

.LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY

DRY NORTHWESTERLY FLOW...WITH A SFC HIGH OVER SOUTHERN WY...WILL
KEEP DRY CONDITIONS IN THE FORECAST TO END THE WORK WEEK. MAIN
FORECAST CHALLENGE WILL BE TEMPERATURES. TEMPS WILL REBOUND SLIGHTLY
FOR THURSDAY...HOWEVER...WITH FRESH SNOW STILL EXPECTED ON THE
GROUND...BELOW AVERAGE LOWS AND HIGHS CAN BE EXPECTED. TEMPS WILL
THEN MAKE A GRADUAL REBOUND THROUGH THE WEEKEND...WITH LOWS IN THE
TEENS AND 20S BY THE END OF THE WEEKEND...AND HIGHS IN THE 30S AND
40S.

STILL LOOKS TO BE ONLY ONE DISTURBANCE WORTH WATCHING FOR LATE IN
THE PERIOD. QUICK MOVING SHORTWAVE DROPS OUT OF CANADA FRIDAY NIGHT
INTO SATURDAY...WITH AN ENHANCED JET STREAK OF AROUND 75 KNOTS.
THIS DISTURBANCE WONT HAVE AN OVERLY ABUNDANT AMOUNT OF
MOISTURE...HOWEVER DEPENDING HOW THIS JET STREAK POSITIONS...AT LEAST
A FEW AREAS COULD SEE AREAS OF LIGHT SNOW...POSSIBLY MIXED WITH RAIN
AT TIMES. PLACED MAINLY SLIGHT CHANCE ACROSS AREAS WITH THE BEST
CHANCES FOR ANY PRECIP...WHICH AT THIS MOMENT APPEARS TO BE MAINLY
THE NORTHWESTERN MOUNTAINS...BIGHORN MOUNTAINS...AND THE LOWER
ELEVATIONS OF THE NORTHERN AND EASTERN CWA. THIS SHORTWAVE AND ITS
ASSOCIATED MOISTURE EXITS SATURDAY NIGHT...ALONG WITH ANY CHANCES
FOR PRECIP. NORTHWEST FLOW RETURNS ON SUNDAY...ALONG WITH A SLIGHT
WARMING TREND...POSSIBLY MAKING IT THE WARMEST DAY OF THE EXTENDED
FORECAST.

&&

.AVIATION.../00Z ISSUANCE/

LOCAL MVFR CEILINGS WILL FLOAT AROUND THE VALLEYS AND BASINS
TONIGHT AND MONDAY MORNING AND MAY TEMPORARILY IMPACT THE AIRPORTS...
OTHERWISE VFR CONDITIONS ARE EXPECTED. THE STRATUS CAN BE EXPECTED
TO LOCALLY OBSCURE THE MOUNTAIN TERRAIN BUT IS NOT EXPECTED TO BE
OF SIGNIFICANT EXTENT.

&&

.FIRE WEATHER...

COLD AIR WILL REMAIN OVER THE NORTH AND CENTRAL AREAS...WHILE
TEMPERATURES WARM ACROSS THE FAR SOUTH WITH LIGHT SNOW...TO A RAIN
SNOW MIX MOVES INTO SOUTHEAST SWEETWATER COUNTY THROUGH THE
AFTERNOON. LOW MIXING HEIGHTS AND POOR SMOKE DISPERSAL WILL PREVAIL
ACROSS CENTRAL AND NORTH WITH FAIR TO LOCALLY GOOD SMOKE DISPERSAL WILL
OCCUR ACROSS THE SOUTH BEFORE THE ONSET OF LOWER CLOUDS AND
PRECIPITATION.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY AFTERNOON
WYZ018>020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM MONDAY TO 6 PM MST TUESDAY
WYZ002>011-015>017-028-029.

&&

$$

SHORT TERM...C.BAKER
MID TERM...ALLEN
LONG TERM...ANGLIN
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER











000
FXUS65 KRIW 012051
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
151 PM MST SUN MAR 1 2015

.SHORT TERM...TONIGHT THROUGH MONDAY

AFTER COLLABORATING WITH MID TERM FORECASTER...CYS AND WYDOT MET HAVE
DELAYED WATCH FOR SWEETWATER UNTIL 00Z TUESDAY.  ALL WINTER HIGHLIGHTS
NOW IN MID TERM PERIOD. SOME STRATUS AND FLURRIES WILL LINGER
AROUND THE VALLEYS AND BASINS TONIGHT.  WARMING WILL OCCUR MAINLY ACROSS
THE SOUTH WHERE MID TO UPPER 30S HIGHS WILL BE POSSIBLE MONDAY
WHERE SOME SNOW...RAIN MIXED WITH SNOW WILL INCREASE THROUGH THE
AFTERNOON. LEAST WARMING WILL BE IN THE NORTH. CLOUDS WILL SPREAD
UP FROM THE SOUTH WHILE THE NORTH AND CENTRAL AREAS AWAIT THE
CANADIAN BLAST OF COLD AIR SNOW AND WIND THAT WILL MOVE IN MONDAY EVENING.
PLEASE REFER TO CYSWSWRIW FOR MORE DETAILS ON THE IMPENDING
WEATHER CHANGE.

.MID TERM...MONDAY NIGHT THROUGH WEDNESDAY

THE PERIOD BEGINS WITH A CORNUCOPIA OF WINTERY CONDITIONS FOR THE
AREA. THE MAIN SHOW WILL FIRST BE SEEDED BY A SYSTEM THAT WILL
IMPACT MOSTLY AREAS TO OUR SOUTH DURING THE SHORT TERM PERIOD...BUT
IT WILL KICK UP A RICHLY MOIST AIRMASS FOR THIS TIME OF YEAR INTO
CENTRAL AND SOUTHERN WYOMING. THIS WILL GIVE OUR SECOND SYSTEM
SOMETHING TO WORK WITH AS IT DROPS SOUTH OUT OF THE DRY ARCTIC
MONDAY NIGHT. THIS SECOND SYSTEM WILL HAVE A LITTLE BIT OF SUPPORT
UPSTAIRS AS IT IS ACCOMPANIED BY A CYCLONICALLY CURVING JET AND SOME
ROBUST QG FORCING. ALSO THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY. HOWEVER...THE COMBINED
IMPACT OF THE SNOW...WIND...LOW WIND CHILLS AND EXPECTED AFFECTS ON
TRAVEL AND CALVING SEASON LEAD TO A LIBERAL ISSUANCE OF WINTER STORM
WATCHES AND ADVISORIES. MOST ELEMENTS WILL BE BORDERLINE BUT THE
COMBINED IMPACT CERTAINLY WARRANTS A HIGHLIGHT OF SOME SORT. WENT
AHEAD AND HIGHLIGHTED THE AREAS WHERE MORE SNOW IS EXPECTED WITH A
WATCH AND KEPT THE OTHERS AT AN ADVISORY. OPTED TO PUSH THE WATCH
FOR SWEETWATER FORWARD TO MONDAY TO HIGHLIGHT THE MORE SIGNIFICANT
IMPACT TO THE POPULATION CENTERS BUT THERE WILL CERTAINLY BE AT
LEAST SOME SNOW DURING THE DAY ON MONDAY FROM THE FIRST
SYSTEM...WHICH COULD BE HEAVY AT TIMES...ESPECIALLY SOUTH OF THE
INTERSTATE.

THINGS BEGIN TO WIND DOWN ON TUESDAY AFTERNOON AS IT CLEARS FROM
NORTH TO SOUTH...TUESDAY NIGHT COULD BE A COLD ONE WHEREVER IT DOES
CLEAR. THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO
MOVE IN HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND
PATCHY FOG EARLY WEDNESDAY MORNING.

.LONG TERM WEDNESDAY NIGHT THROUGH SUNDAY

DRY NORTHWESTERLY FLOW...WITH A SFC HIGH OVER SOUTHERN WY...WILL
KEEP DRY CONDITIONS IN THE FORECAST TO END THE WORK WEEK. MAIN
FORECAST CHALLENGE WILL BE TEMPERATURES. TEMPS WILL REBOUND SLIGHTLY
FOR THURSDAY...HOWEVER...WITH FRESH SNOW STILL EXPECTED ON THE
GROUND...BELOW AVERAGE LOWS AND HIGHS CAN BE EXPECTED. TEMPS WILL
THEN MAKE A GRADUAL REBOUND THROUGH THE WEEKEND...WITH LOWS IN THE
TEENS AND 20S BY THE END OF THE WEEKEND...AND HIGHS IN THE 30S AND
40S.

STILL LOOKS TO BE ONLY ONE DISTURBANCE WORTH WATCHING FOR LATE IN
THE PERIOD. QUICK MOVING SHORTWAVE DROPS OUT OF CANADA FRIDAY NIGHT
INTO SATURDAY...WITH AN ENHANCED JET STREAK OF AROUND 75 KNOTS.
THIS DISTURBANCE WONT HAVE AN OVERLY ABUNDANT AMOUNT OF
MOISTURE...HOWEVER DEPENDING HOW THIS JET STREAK POSITIONS...AT LEAST
A FEW AREAS COULD SEE AREAS OF LIGHT SNOW...POSSIBLY MIXED WITH RAIN
AT TIMES. PLACED MAINLY SLIGHT CHANCE ACROSS AREAS WITH THE BEST
CHANCES FOR ANY PRECIP...WHICH AT THIS MOMENT APPEARS TO BE MAINLY
THE NORTHWESTERN MOUNTAINS...BIGHORN MOUNTAINS...AND THE LOWER
ELEVATIONS OF THE NORTHERN AND EASTERN CWA. THIS SHORTWAVE AND ITS
ASSOCIATED MOISTURE EXITS SATURDAY NIGHT...ALONG WITH ANY CHANCES
FOR PRECIP. NORTHWEST FLOW RETURNS ON SUNDAY...ALONG WITH A SLIGHT
WARMING TREND...POSSIBLY MAKING IT THE WARMEST DAY OF THE EXTENDED
FORECAST.

&&

.AVIATION.../00Z ISSUANCE/

LOCAL MVFR CEILINGS WILL FLOAT AROUND THE VALLEYS AND BASINS
TONIGHT AND MONDAY MORNING AND MAY TEMPORARILY IMPACT THE AIRPORTS...
OTHERWISE VFR CONDITIONS ARE EXPECTED. THE STRATUS CAN BE EXPECTED
TO LOCALLY OBSCURE THE MOUNTAIN TERRAIN BUT IS NOT EXPECTED TO BE
OF SIGNIFICANT EXTENT.

&&

.FIRE WEATHER...

COLD AIR WILL REMAIN OVER THE NORTH AND CENTRAL AREAS...WHILE
TEMPERATURES WARM ACROSS THE FAR SOUTH WITH LIGHT SNOW...TO A RAIN
SNOW MIX MOVES INTO SOUTHEAST SWEETWATER COUNTY THROUGH THE
AFTERNOON. LOW MIXING HEIGHTS AND POOR SMOKE DISPERSAL WILL PREVAIL
ACROSS CENTRAL AND NORTH WITH FAIR TO LOCALLY GOOD SMOKE DISPERSAL WILL
OCCUR ACROSS THE SOUTH BEFORE THE ONSET OF LOWER CLOUDS AND
PRECIPITATION.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM MONDAY EVENING THROUGH TUESDAY AFTERNOON
WYZ018>020-022-030.

WINTER WEATHER ADVISORY FROM 6 PM MONDAY TO 6 PM MST TUESDAY
WYZ002>011-015>017-028-029.

&&

$$

SHORT TERM...C.BAKER
MID TERM...ALLEN
LONG TERM...ANGLIN
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER










000
FXUS65 KRIW 011853
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1153 AM MST SUN MAR 1 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

AN INTERESTING FORECAST PERIOD ACROSS WESTERN AND CENTRAL WYOMING. A
FAIRLY QUIET BEGINNING AS LINGER ACTIVITY OTHER SOUTHERN WYOMING
TAPERS OFF THIS MORNING. MORNING INVERSIONS WILL DEVELOP...WITH
PATCHY FOG POSSIBLE ACROSS MUCH OF THE LOW LYING AREAS.

A BRIEF PERIOD OF DRY CONDITIONS ANTICIPATED THROUGH THE OVERNIGHT
HOURS. WHILE THE DRY PERIOD IS ONGOING...AN AREA OF LOW PRESSURE
WILL MOVE SOUTH ALONG THE PACIFIC COASTLINE...FINALLY HEADING INLAND
TOWARDS THE FOUR CORNERS REGION LATE TONIGHT AND INTO MONDAY. AS
THIS SYSTEM PROGRESSES IT WILL SEND SNOWFALL ACROSS THE SOUTHERN
THIRD OF THE FORECAST AREA...ESPECIALLY IMPACTING SOUTHERN
SWEETWATER COUNTY BY MONDAY MORNING. SNOWFALL WILL INCREASE MONDAY
AFTERNOON AND MONDAY NIGHT...AND IS FAVORABLE TO BECOME HEAVY AT
TIMES. SNOWFALL ACCUMULATIONS OF 4 TO 7 INCHES ARE POSSIBLE BY
TUESDAY EVENING...AND ARE SUPPORTED BY NATIONAL CENTERS. SOME
HIGHER AMOUNTS ARE POSSIBLE SOUTH OF INTERSTATE 80. WITH CONCERNS
RELATING TO THIS SYSTEM MOUNTING...HAVE ISSUED A WINTER STORM WATCH
FOR THE COUNTY. INTERSTATE 80 WILL BE IMPACTED...THOUGH AGAIN...THE
GREATEST AREA OF IMPACT LOOKS TO BE SOUTH OF THE
INTERSTATE...ESPECIALLY ALONG THE WYOMING AND COLORADO BORDER.

AS THIS SYSTEM IS IMPACTING THE SOUTHERN PORTION OF THE FORECAST
AREA... A WAVE OF LOW PRESSURE LOOKS TO SEND A CANADIAN SYSTEM INTO
NORTHERN WYOMING BY LATE MONDAY NIGHT. SNOWFALL WITH THIS SYSTEM
WILL ESPECIALLY IMPACT THE NORTHERN MOUNTAINS...AND WILL CONTINUE TO
BE MONITORED. EVENTUALLY...THE NORTHERN SYSTEM LOOKS TO TAKE OVER
THE SOUTHERN SYSTEM...WITH SNOWFALL SPREADING TO INCLUDE THE VAST
MAJORITY OF THE FORECAST AREA DURING THE VERY EARLY MORNING HOURS OF
TUESDAY. ALL SITUATIONS WILL CONTINUE TO BE MONITORED...THOUGH
REGARDLESS EVEN TO AMOUNTS...EXPECT A RETURN TO COOLER WEATHER WITH
SNOWFALL VERY FAVORABLE OVER THE AREA.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

NORTHWEST FLOW IS EXPECTED TO DOMINATE THE EXTENDED WITH AT LEAST
ONE DISTINCT SHORTWAVE TROUGH AND ASSOCIATED WEAK COLD FRONT SLIDING
ACROSS THE AREA IN THE FRIDAY/FRIDAY NIGHT TIME FRAME. OTHERWISE...A
RELATIVELY DRY NORTHWEST FLOW IS EXPECTED. WILL INTRODUCE SLIGHT
MOUNTAIN POPS FOR THIS SYSTEM FRIDAY/FRIDAY NIGHT...BUT KEPT THE
LOWER ELEVATIONS DRY FOR NOW...AS THIS SYSTEM APPEARS TO HAVE
LIMITED AVAILABLE MOISTURE.  CANNOT RULE OUT ISOLATED MOUNTAIN SNOW
SHOWERS ON OTHER DAYS MAINLY OVER THE NORTHWEST/NORTHERN
MOUNTAINS...BUT PREVIOUS FORECASTS WERE DRY...AND MOISTURE IS NOT
EXCITING...THUS HAVE KEPT THE ONGOING DRY FORECAST.

TEMPERATURES ON WEDNESDAY WILL BE 15 TO 25 DEGREES BELOW
AVERAGE...WITH SOME AREAS SEEING HIGHS ABOUT 30 DEGREES BELOW
AVERAGE. A WARMING TREND WILL OCCUR LATE THIS WEEK WITH MOST AREAS
RETURNING TO SEASONAL LEVELS BY FRIDAY. THE EXCEPTION WILL PROBABLY
BE TYPICAL TRAPPED CENTRAL BASINS WHERE MODELS TEND TO WARM THEM UP
TOO QUICKLY. A WEAK COLD FRONT FRIDAY/FRIDAY NIGHT...MIGHT ACTUALLY
HELP MIX OUT THOSE TRAPPED BASINS.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED AT THE AIRPORTS THROUGH 18Z MONDAY.
OVER THE MOUNTAINS LOCAL STRATUS WILL CAUSE MVFR CEILINGS WITH
VERY LIGHT SNOW ABOVE 9000 FEET.

.FIRE WEATHER...

ANOTHER RETURN TO WINTER EXPECTED OVER THE NEXT FEW DAYS. GENERALLY
DRY CONDITIONS ANTICIPATED TODAY...WITH MORNING INVERSIONS AND
RELATED PATCHY FOG POSSIBLE. A WINTRY SYSTEM WILL THEN MOVE INTO
SOUTHERN WYOMING MONDAY MORNING...SPREADING SNOWFALL ACROSS
SWEETWATER COUNTY. ANOTHER SYSTEM WILL THEN MOVE INTO NORTHERN
WYOMING MONDAY NIGHT SPREADING SNOWFALL ACROSS THE NORTHERN THIRD OF
THE FORECAST AREA. THESE TWO SYSTEM ARE EXPECTED TO JOIN DURING THE
VERY EARLY MORNING OF TUESDAY...WITH WIDESPREAD SNOWFALL
ANTICIPATED. IT APPEARS AS THOUGH THE GREATEST SNOWFALL AMOUNTS MAY
FALL OVER SOUTHERN WYOMING...WITH A WINTER STORM WATCH ISSUED FOR
THE AREA. STAY TUNED FOR UPDATES TO THIS UPCOMING STORM SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
AFTERNOON WYZ028>030.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...C.BAKER
FIRE WEATHER...BRANHAM







000
FXUS65 KRIW 011853
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1153 AM MST SUN MAR 1 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

AN INTERESTING FORECAST PERIOD ACROSS WESTERN AND CENTRAL WYOMING. A
FAIRLY QUIET BEGINNING AS LINGER ACTIVITY OTHER SOUTHERN WYOMING
TAPERS OFF THIS MORNING. MORNING INVERSIONS WILL DEVELOP...WITH
PATCHY FOG POSSIBLE ACROSS MUCH OF THE LOW LYING AREAS.

A BRIEF PERIOD OF DRY CONDITIONS ANTICIPATED THROUGH THE OVERNIGHT
HOURS. WHILE THE DRY PERIOD IS ONGOING...AN AREA OF LOW PRESSURE
WILL MOVE SOUTH ALONG THE PACIFIC COASTLINE...FINALLY HEADING INLAND
TOWARDS THE FOUR CORNERS REGION LATE TONIGHT AND INTO MONDAY. AS
THIS SYSTEM PROGRESSES IT WILL SEND SNOWFALL ACROSS THE SOUTHERN
THIRD OF THE FORECAST AREA...ESPECIALLY IMPACTING SOUTHERN
SWEETWATER COUNTY BY MONDAY MORNING. SNOWFALL WILL INCREASE MONDAY
AFTERNOON AND MONDAY NIGHT...AND IS FAVORABLE TO BECOME HEAVY AT
TIMES. SNOWFALL ACCUMULATIONS OF 4 TO 7 INCHES ARE POSSIBLE BY
TUESDAY EVENING...AND ARE SUPPORTED BY NATIONAL CENTERS. SOME
HIGHER AMOUNTS ARE POSSIBLE SOUTH OF INTERSTATE 80. WITH CONCERNS
RELATING TO THIS SYSTEM MOUNTING...HAVE ISSUED A WINTER STORM WATCH
FOR THE COUNTY. INTERSTATE 80 WILL BE IMPACTED...THOUGH AGAIN...THE
GREATEST AREA OF IMPACT LOOKS TO BE SOUTH OF THE
INTERSTATE...ESPECIALLY ALONG THE WYOMING AND COLORADO BORDER.

AS THIS SYSTEM IS IMPACTING THE SOUTHERN PORTION OF THE FORECAST
AREA... A WAVE OF LOW PRESSURE LOOKS TO SEND A CANADIAN SYSTEM INTO
NORTHERN WYOMING BY LATE MONDAY NIGHT. SNOWFALL WITH THIS SYSTEM
WILL ESPECIALLY IMPACT THE NORTHERN MOUNTAINS...AND WILL CONTINUE TO
BE MONITORED. EVENTUALLY...THE NORTHERN SYSTEM LOOKS TO TAKE OVER
THE SOUTHERN SYSTEM...WITH SNOWFALL SPREADING TO INCLUDE THE VAST
MAJORITY OF THE FORECAST AREA DURING THE VERY EARLY MORNING HOURS OF
TUESDAY. ALL SITUATIONS WILL CONTINUE TO BE MONITORED...THOUGH
REGARDLESS EVEN TO AMOUNTS...EXPECT A RETURN TO COOLER WEATHER WITH
SNOWFALL VERY FAVORABLE OVER THE AREA.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

NORTHWEST FLOW IS EXPECTED TO DOMINATE THE EXTENDED WITH AT LEAST
ONE DISTINCT SHORTWAVE TROUGH AND ASSOCIATED WEAK COLD FRONT SLIDING
ACROSS THE AREA IN THE FRIDAY/FRIDAY NIGHT TIME FRAME. OTHERWISE...A
RELATIVELY DRY NORTHWEST FLOW IS EXPECTED. WILL INTRODUCE SLIGHT
MOUNTAIN POPS FOR THIS SYSTEM FRIDAY/FRIDAY NIGHT...BUT KEPT THE
LOWER ELEVATIONS DRY FOR NOW...AS THIS SYSTEM APPEARS TO HAVE
LIMITED AVAILABLE MOISTURE.  CANNOT RULE OUT ISOLATED MOUNTAIN SNOW
SHOWERS ON OTHER DAYS MAINLY OVER THE NORTHWEST/NORTHERN
MOUNTAINS...BUT PREVIOUS FORECASTS WERE DRY...AND MOISTURE IS NOT
EXCITING...THUS HAVE KEPT THE ONGOING DRY FORECAST.

TEMPERATURES ON WEDNESDAY WILL BE 15 TO 25 DEGREES BELOW
AVERAGE...WITH SOME AREAS SEEING HIGHS ABOUT 30 DEGREES BELOW
AVERAGE. A WARMING TREND WILL OCCUR LATE THIS WEEK WITH MOST AREAS
RETURNING TO SEASONAL LEVELS BY FRIDAY. THE EXCEPTION WILL PROBABLY
BE TYPICAL TRAPPED CENTRAL BASINS WHERE MODELS TEND TO WARM THEM UP
TOO QUICKLY. A WEAK COLD FRONT FRIDAY/FRIDAY NIGHT...MIGHT ACTUALLY
HELP MIX OUT THOSE TRAPPED BASINS.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED AT THE AIRPORTS THROUGH 18Z MONDAY.
OVER THE MOUNTAINS LOCAL STRATUS WILL CAUSE MVFR CEILINGS WITH
VERY LIGHT SNOW ABOVE 9000 FEET.

.FIRE WEATHER...

ANOTHER RETURN TO WINTER EXPECTED OVER THE NEXT FEW DAYS. GENERALLY
DRY CONDITIONS ANTICIPATED TODAY...WITH MORNING INVERSIONS AND
RELATED PATCHY FOG POSSIBLE. A WINTRY SYSTEM WILL THEN MOVE INTO
SOUTHERN WYOMING MONDAY MORNING...SPREADING SNOWFALL ACROSS
SWEETWATER COUNTY. ANOTHER SYSTEM WILL THEN MOVE INTO NORTHERN
WYOMING MONDAY NIGHT SPREADING SNOWFALL ACROSS THE NORTHERN THIRD OF
THE FORECAST AREA. THESE TWO SYSTEM ARE EXPECTED TO JOIN DURING THE
VERY EARLY MORNING OF TUESDAY...WITH WIDESPREAD SNOWFALL
ANTICIPATED. IT APPEARS AS THOUGH THE GREATEST SNOWFALL AMOUNTS MAY
FALL OVER SOUTHERN WYOMING...WITH A WINTER STORM WATCH ISSUED FOR
THE AREA. STAY TUNED FOR UPDATES TO THIS UPCOMING STORM SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
AFTERNOON WYZ028>030.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...C.BAKER
FIRE WEATHER...BRANHAM






000
FXUS65 KRIW 011853
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1153 AM MST SUN MAR 1 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

AN INTERESTING FORECAST PERIOD ACROSS WESTERN AND CENTRAL WYOMING. A
FAIRLY QUIET BEGINNING AS LINGER ACTIVITY OTHER SOUTHERN WYOMING
TAPERS OFF THIS MORNING. MORNING INVERSIONS WILL DEVELOP...WITH
PATCHY FOG POSSIBLE ACROSS MUCH OF THE LOW LYING AREAS.

A BRIEF PERIOD OF DRY CONDITIONS ANTICIPATED THROUGH THE OVERNIGHT
HOURS. WHILE THE DRY PERIOD IS ONGOING...AN AREA OF LOW PRESSURE
WILL MOVE SOUTH ALONG THE PACIFIC COASTLINE...FINALLY HEADING INLAND
TOWARDS THE FOUR CORNERS REGION LATE TONIGHT AND INTO MONDAY. AS
THIS SYSTEM PROGRESSES IT WILL SEND SNOWFALL ACROSS THE SOUTHERN
THIRD OF THE FORECAST AREA...ESPECIALLY IMPACTING SOUTHERN
SWEETWATER COUNTY BY MONDAY MORNING. SNOWFALL WILL INCREASE MONDAY
AFTERNOON AND MONDAY NIGHT...AND IS FAVORABLE TO BECOME HEAVY AT
TIMES. SNOWFALL ACCUMULATIONS OF 4 TO 7 INCHES ARE POSSIBLE BY
TUESDAY EVENING...AND ARE SUPPORTED BY NATIONAL CENTERS. SOME
HIGHER AMOUNTS ARE POSSIBLE SOUTH OF INTERSTATE 80. WITH CONCERNS
RELATING TO THIS SYSTEM MOUNTING...HAVE ISSUED A WINTER STORM WATCH
FOR THE COUNTY. INTERSTATE 80 WILL BE IMPACTED...THOUGH AGAIN...THE
GREATEST AREA OF IMPACT LOOKS TO BE SOUTH OF THE
INTERSTATE...ESPECIALLY ALONG THE WYOMING AND COLORADO BORDER.

AS THIS SYSTEM IS IMPACTING THE SOUTHERN PORTION OF THE FORECAST
AREA... A WAVE OF LOW PRESSURE LOOKS TO SEND A CANADIAN SYSTEM INTO
NORTHERN WYOMING BY LATE MONDAY NIGHT. SNOWFALL WITH THIS SYSTEM
WILL ESPECIALLY IMPACT THE NORTHERN MOUNTAINS...AND WILL CONTINUE TO
BE MONITORED. EVENTUALLY...THE NORTHERN SYSTEM LOOKS TO TAKE OVER
THE SOUTHERN SYSTEM...WITH SNOWFALL SPREADING TO INCLUDE THE VAST
MAJORITY OF THE FORECAST AREA DURING THE VERY EARLY MORNING HOURS OF
TUESDAY. ALL SITUATIONS WILL CONTINUE TO BE MONITORED...THOUGH
REGARDLESS EVEN TO AMOUNTS...EXPECT A RETURN TO COOLER WEATHER WITH
SNOWFALL VERY FAVORABLE OVER THE AREA.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

NORTHWEST FLOW IS EXPECTED TO DOMINATE THE EXTENDED WITH AT LEAST
ONE DISTINCT SHORTWAVE TROUGH AND ASSOCIATED WEAK COLD FRONT SLIDING
ACROSS THE AREA IN THE FRIDAY/FRIDAY NIGHT TIME FRAME. OTHERWISE...A
RELATIVELY DRY NORTHWEST FLOW IS EXPECTED. WILL INTRODUCE SLIGHT
MOUNTAIN POPS FOR THIS SYSTEM FRIDAY/FRIDAY NIGHT...BUT KEPT THE
LOWER ELEVATIONS DRY FOR NOW...AS THIS SYSTEM APPEARS TO HAVE
LIMITED AVAILABLE MOISTURE.  CANNOT RULE OUT ISOLATED MOUNTAIN SNOW
SHOWERS ON OTHER DAYS MAINLY OVER THE NORTHWEST/NORTHERN
MOUNTAINS...BUT PREVIOUS FORECASTS WERE DRY...AND MOISTURE IS NOT
EXCITING...THUS HAVE KEPT THE ONGOING DRY FORECAST.

TEMPERATURES ON WEDNESDAY WILL BE 15 TO 25 DEGREES BELOW
AVERAGE...WITH SOME AREAS SEEING HIGHS ABOUT 30 DEGREES BELOW
AVERAGE. A WARMING TREND WILL OCCUR LATE THIS WEEK WITH MOST AREAS
RETURNING TO SEASONAL LEVELS BY FRIDAY. THE EXCEPTION WILL PROBABLY
BE TYPICAL TRAPPED CENTRAL BASINS WHERE MODELS TEND TO WARM THEM UP
TOO QUICKLY. A WEAK COLD FRONT FRIDAY/FRIDAY NIGHT...MIGHT ACTUALLY
HELP MIX OUT THOSE TRAPPED BASINS.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED AT THE AIRPORTS THROUGH 18Z MONDAY.
OVER THE MOUNTAINS LOCAL STRATUS WILL CAUSE MVFR CEILINGS WITH
VERY LIGHT SNOW ABOVE 9000 FEET.

.FIRE WEATHER...

ANOTHER RETURN TO WINTER EXPECTED OVER THE NEXT FEW DAYS. GENERALLY
DRY CONDITIONS ANTICIPATED TODAY...WITH MORNING INVERSIONS AND
RELATED PATCHY FOG POSSIBLE. A WINTRY SYSTEM WILL THEN MOVE INTO
SOUTHERN WYOMING MONDAY MORNING...SPREADING SNOWFALL ACROSS
SWEETWATER COUNTY. ANOTHER SYSTEM WILL THEN MOVE INTO NORTHERN
WYOMING MONDAY NIGHT SPREADING SNOWFALL ACROSS THE NORTHERN THIRD OF
THE FORECAST AREA. THESE TWO SYSTEM ARE EXPECTED TO JOIN DURING THE
VERY EARLY MORNING OF TUESDAY...WITH WIDESPREAD SNOWFALL
ANTICIPATED. IT APPEARS AS THOUGH THE GREATEST SNOWFALL AMOUNTS MAY
FALL OVER SOUTHERN WYOMING...WITH A WINTER STORM WATCH ISSUED FOR
THE AREA. STAY TUNED FOR UPDATES TO THIS UPCOMING STORM SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
AFTERNOON WYZ028>030.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...C.BAKER
FIRE WEATHER...BRANHAM







000
FXUS65 KRIW 011853
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1153 AM MST SUN MAR 1 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

AN INTERESTING FORECAST PERIOD ACROSS WESTERN AND CENTRAL WYOMING. A
FAIRLY QUIET BEGINNING AS LINGER ACTIVITY OTHER SOUTHERN WYOMING
TAPERS OFF THIS MORNING. MORNING INVERSIONS WILL DEVELOP...WITH
PATCHY FOG POSSIBLE ACROSS MUCH OF THE LOW LYING AREAS.

A BRIEF PERIOD OF DRY CONDITIONS ANTICIPATED THROUGH THE OVERNIGHT
HOURS. WHILE THE DRY PERIOD IS ONGOING...AN AREA OF LOW PRESSURE
WILL MOVE SOUTH ALONG THE PACIFIC COASTLINE...FINALLY HEADING INLAND
TOWARDS THE FOUR CORNERS REGION LATE TONIGHT AND INTO MONDAY. AS
THIS SYSTEM PROGRESSES IT WILL SEND SNOWFALL ACROSS THE SOUTHERN
THIRD OF THE FORECAST AREA...ESPECIALLY IMPACTING SOUTHERN
SWEETWATER COUNTY BY MONDAY MORNING. SNOWFALL WILL INCREASE MONDAY
AFTERNOON AND MONDAY NIGHT...AND IS FAVORABLE TO BECOME HEAVY AT
TIMES. SNOWFALL ACCUMULATIONS OF 4 TO 7 INCHES ARE POSSIBLE BY
TUESDAY EVENING...AND ARE SUPPORTED BY NATIONAL CENTERS. SOME
HIGHER AMOUNTS ARE POSSIBLE SOUTH OF INTERSTATE 80. WITH CONCERNS
RELATING TO THIS SYSTEM MOUNTING...HAVE ISSUED A WINTER STORM WATCH
FOR THE COUNTY. INTERSTATE 80 WILL BE IMPACTED...THOUGH AGAIN...THE
GREATEST AREA OF IMPACT LOOKS TO BE SOUTH OF THE
INTERSTATE...ESPECIALLY ALONG THE WYOMING AND COLORADO BORDER.

AS THIS SYSTEM IS IMPACTING THE SOUTHERN PORTION OF THE FORECAST
AREA... A WAVE OF LOW PRESSURE LOOKS TO SEND A CANADIAN SYSTEM INTO
NORTHERN WYOMING BY LATE MONDAY NIGHT. SNOWFALL WITH THIS SYSTEM
WILL ESPECIALLY IMPACT THE NORTHERN MOUNTAINS...AND WILL CONTINUE TO
BE MONITORED. EVENTUALLY...THE NORTHERN SYSTEM LOOKS TO TAKE OVER
THE SOUTHERN SYSTEM...WITH SNOWFALL SPREADING TO INCLUDE THE VAST
MAJORITY OF THE FORECAST AREA DURING THE VERY EARLY MORNING HOURS OF
TUESDAY. ALL SITUATIONS WILL CONTINUE TO BE MONITORED...THOUGH
REGARDLESS EVEN TO AMOUNTS...EXPECT A RETURN TO COOLER WEATHER WITH
SNOWFALL VERY FAVORABLE OVER THE AREA.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

NORTHWEST FLOW IS EXPECTED TO DOMINATE THE EXTENDED WITH AT LEAST
ONE DISTINCT SHORTWAVE TROUGH AND ASSOCIATED WEAK COLD FRONT SLIDING
ACROSS THE AREA IN THE FRIDAY/FRIDAY NIGHT TIME FRAME. OTHERWISE...A
RELATIVELY DRY NORTHWEST FLOW IS EXPECTED. WILL INTRODUCE SLIGHT
MOUNTAIN POPS FOR THIS SYSTEM FRIDAY/FRIDAY NIGHT...BUT KEPT THE
LOWER ELEVATIONS DRY FOR NOW...AS THIS SYSTEM APPEARS TO HAVE
LIMITED AVAILABLE MOISTURE.  CANNOT RULE OUT ISOLATED MOUNTAIN SNOW
SHOWERS ON OTHER DAYS MAINLY OVER THE NORTHWEST/NORTHERN
MOUNTAINS...BUT PREVIOUS FORECASTS WERE DRY...AND MOISTURE IS NOT
EXCITING...THUS HAVE KEPT THE ONGOING DRY FORECAST.

TEMPERATURES ON WEDNESDAY WILL BE 15 TO 25 DEGREES BELOW
AVERAGE...WITH SOME AREAS SEEING HIGHS ABOUT 30 DEGREES BELOW
AVERAGE. A WARMING TREND WILL OCCUR LATE THIS WEEK WITH MOST AREAS
RETURNING TO SEASONAL LEVELS BY FRIDAY. THE EXCEPTION WILL PROBABLY
BE TYPICAL TRAPPED CENTRAL BASINS WHERE MODELS TEND TO WARM THEM UP
TOO QUICKLY. A WEAK COLD FRONT FRIDAY/FRIDAY NIGHT...MIGHT ACTUALLY
HELP MIX OUT THOSE TRAPPED BASINS.

.AVIATION.../18Z ISSUANCE/

VFR CONDITIONS ARE EXPECTED AT THE AIRPORTS THROUGH 18Z MONDAY.
OVER THE MOUNTAINS LOCAL STRATUS WILL CAUSE MVFR CEILINGS WITH
VERY LIGHT SNOW ABOVE 9000 FEET.

.FIRE WEATHER...

ANOTHER RETURN TO WINTER EXPECTED OVER THE NEXT FEW DAYS. GENERALLY
DRY CONDITIONS ANTICIPATED TODAY...WITH MORNING INVERSIONS AND
RELATED PATCHY FOG POSSIBLE. A WINTRY SYSTEM WILL THEN MOVE INTO
SOUTHERN WYOMING MONDAY MORNING...SPREADING SNOWFALL ACROSS
SWEETWATER COUNTY. ANOTHER SYSTEM WILL THEN MOVE INTO NORTHERN
WYOMING MONDAY NIGHT SPREADING SNOWFALL ACROSS THE NORTHERN THIRD OF
THE FORECAST AREA. THESE TWO SYSTEM ARE EXPECTED TO JOIN DURING THE
VERY EARLY MORNING OF TUESDAY...WITH WIDESPREAD SNOWFALL
ANTICIPATED. IT APPEARS AS THOUGH THE GREATEST SNOWFALL AMOUNTS MAY
FALL OVER SOUTHERN WYOMING...WITH A WINTER STORM WATCH ISSUED FOR
THE AREA. STAY TUNED FOR UPDATES TO THIS UPCOMING STORM SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM MONDAY AFTERNOON THROUGH TUESDAY
AFTERNOON WYZ028>030.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...C.BAKER
FIRE WEATHER...BRANHAM






000
FXUS65 KCYS 011754
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1054 AM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 1055 AM MST SUN MAR 1 2015

NO CHANGES TO THE FORECAST TODAY. MAIN FOCUS REMAINS ON THE STORM
SYSTEM WHICH WILL MOVE ACROSS THE AREA TOMORROW AND TOMORROW
NIGHT. MODELS NOT IN GREAT AGREEMENT WITH WHERE THE HEAVIEST SNOW
WILL FALL...BUT THERE IS GENERAL CONSENSUS POINTS TO SOUTH
CENTRAL WYOMING. CURRENT WATER VAPOR AND RADAR OVER THE SOUTHWEST
CONUS SHOWING MOISTURE STREAMING NORTHEASTWARD FROM ARIZONA. SEEMS
REASONABLE THERE WILL BE WIDESPREAD SNOW ACROSS THE ENTIRE AREA BY
MONDAY NIGHT AS AN UPPER LEVEL DISTURBANCE MOVES FROM THE CENTRAL
ROCKIES INTO THE NORTHERN PLAINS.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 400 AM MST SUN MAR 1 2015

LATEST GOES WATER VAPOR IMAGERY SHOWED THE SPLIT CLOSED UPPER LOW
SLOWLY SINKING SOUTHEAST ALONG THE CENTRAL CA COAST. THE BASE OF
THE NORTHERN STREAM TROUGH WAS MOVING EAST ACROSS THE DAKOTAS. A
DEFORMATION ZONE STRETCHED NORTHEAST TO SOUTHWEST FROM WESTERN NE
ACROSS NORTHERN CO. NARROW BAND OF UPPER LIFT COMBINED WITH MOISTURE
AND WEAK UPSLOPE RESULTED IN AN AREA OF LIGHT SNOW OVER PORTIONS
OF SOUTHEAST WY AND WESTERN NE. HRRR MODEL PROGS THIS AREA TO WEAKEN
AS IT MOVES FURTHER EAST THROUGH DAYBREAK. TEMPERATURES WERE IN THE
SINGLE DIGITS AND TEENS WITH LIGHT WINDS.

FORECAST CONCERNS DURING THE SHORT TERM WILL FOCUS ON THE DEVELOPING
WINTER STORM AND ITS IMPACTS ON OUR AREA...PARTICULARLY FROM LATE
TONIGHT THROUGH TUESDAY. CLOSED UPPER LOW NEAR SOUTHERN CA COAST
GRADUALLY OPENS UP AND EJECTS NORTHEAST AS ANOTHER SHORTWAVE DROPS
SOUTH ALONG THE CA COAST DURING THE NEXT 24 TO 48 HOURS. THE MODEL
CONSENSUS PROGS A LOW PRESSURE SYSTEM TO FORM NEAR THE FOUR CORNERS
REGION AND TRACK NORTHEAST ACROSS COLORADO. LIGHT SNOW REDEVELOPS
LATER TODAY OVER THE SOUTHERN MOUNTAINS AND BECOMES MORE WIDESPREAD
AND HEAVIER LATE TONIGHT INTO MONDAY. THE GFS IS SLIGHTLY DEEPER
AND FASTER THAN THE ECMWF WITH REGARDS TO THE SURFACE LOW AND ITS
MOTION. THEY ARE SIMILAR WITH THE EASTWARD TRACK OF THE LOW INTO
THE CENTRAL PLAINS EARLY TUESDAY MORNING. THEY ALSO AGREE WITH THE
ARCTIC COLD FRONTAL PASSAGE DURING THIS TIME PERIOD. WINDS SHIFT
TO NORTHERLY AND BECOME GUSTY TUESDAY. SNOW WILL BE WIDESPREAD
OVER THE CWA MONDAY NIGHT AND TUESDAY. THE COMBINATION OF FALLING
AND BLOWING SNOW WILL RESULT IN HAZARDOUS TRAVEL WEST OF THE
LARAMIE RANGE...ESPECIALLY MONDAY THROUGH TUESDAY. LATEST WPC
GUIDANCE PROGS 1-2 FT OF SNOW FOR THE SNOWY/SIERRA MADRE RANGES
WITH UP TO A FOOT FOR THE NEARBY VALLEYS. ISSUED A WINTER STORM
WATCH FOR WY ZONES 111-114 LATE TONIGHT THROUGH LATE TUESDAY NIGHT
FOR THE POTENTIAL OF HEAVY SNOW. FURTHER NORTH AND EAST...WE`RE
LOOKING AT ADVISORY ACCUMULATIONS...GENERALLY 4-8 INCHES. THE
SOUTHERN LARAMIE RANGE COULD GET CLOSE TO A FOOT AS WELL. THE NEXT
SHIFT MAY UPGRADE AND/OR EXTEND THE WINTER HEADLINES AFTER LOOKING
AT THE 12Z/18Z MODEL GUIDANCE.

HIGHS TODAY WILL BE SIMILAR TO SATURDAY WITH MOSTLY UPPER TEENS TO
UPPER 20S. LOWS TONIGHT AND MONDAY NIGHT WILL AVERAGE IN THE TEENS.
MONDAY WILL BE MILDER WITH SOUTHWESTERLY WINDS. EXPECT HIGHS IN THE
30S TO AROUND 40. TEMPERATURES TUESDAY WILL NOT RISE MUCH FROM THE
EARLY MORNING LOWS...AND WILL BE FALLING THROUGH THE DAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM MST SUN MAR 1 2015

THE MAIN CHALLENGE IN THE EXTENDED WILL BE TEMPERATURE TRENDS AS WE
STILL ANTICIPATE A BAND OF NEW SNOWPACK SOMEWHERE IN THE CWA. GFS/EC
BOTH SHOW A SECONDARY SHORTWAVE DIVING ACROSS WY BETWEEN 00Z AND 12Z
WED. MODEST PVA SHOULD BE ENOUGH FOR SNOW SHOWERS TO LINGER INTO WED
MORNING OR PERHAPS EARLY AFTERNOON. MEDIUM RANGE 700-300 MILLIBAR RH
PROGS SUGGEST A DRYING COLUMN BY THIS TIME...SO EXPECT LESS THAN AN
INCH OF ADDITIONAL ACCUMULATION OVER THE LOWER ELEVATIONS AFTER 00Z
WED. TEMPERATURES WILL BE TRICKY ON TUE NIGHT AS CLOUDS WILL PREVENT
SIGNIFICANT RADIATIONAL COOLING. HOWEVER...MODELS AGREE WITH STRONG
LOW LEVEL COLD ADVECTION PUSHING H7 TEMPS AS LOW AS -20 DEG C BY 12Z
WED PER THE EURO. GIVEN AN AIR MASS THIS COLD...CONFIDENCE IS FAIRLY
HIGH THAT MANY AREAS WILL BE BELOW ZERO FOR LOWS. DID NOT STRAY TOO
FAR AWAY FROM GUIDANCE THOUGH. COOLEST TEMPERATURES ON WED SHOULD BE
FOUND OVER THE MOST SUBSTANTIAL SNOWPACK. GUIDANCE SUGGESTS THE BEST
CHANCE FOR LOW-ELEVATION SIGNIFICANT SNOWFALL EARLY IN THE WEEK WILL
BE WEST OF THE LARAMIE RANGE...SO UNDERCUT MOS BY SEVERAL DEGREES IN
THOSE AREAS. KEPT HIGHS BELOW GUIDANCE ACROSS THE BOARD WITH MUCH OF
THE AREA LIKELY TO RECEIVE ACCUMULATING SNOW IN THE SHORT TERM.

IMPROVING TEMPERATURES LATER IN THE WEEK AS UPPER-LEVEL RIDGING AND
LOW LEVEL DOWNSLOPE RETURN TO THE REGION. A BACK DOOR COLD FRONT IS
PROGGED TO SINK SOUTHWARD ON FRI AFTERNOON...POSSIBLY HAVING A SMALL
IMPACT ON HIGHS WITH COLD ADVECTION ALOFT. CANNOT RULE OUT ISOLATED
RAIN OR SNOW SHOWERS ON FRI NIGHT OR SAT MORNING WITH THE ARRIVAL OF
BETTER MID LEVEL SUPPORT. HOWEVER...KEPT THE FORECAST DRY FOR NOW AS
THIS SYSTEM LOOKS TO BE A BIT MOISTURE STARVED. STILL EXPECT A WINDY
PERIOD FROM WED NIGHT THROUGH FRI OVER THE WIND PRONE AREAS. THE GFS
HAS BEEN CONSISTENT WITH A STRONG H85 CAG-CPR GRADIENT IN EXCESS OF
60 METERS AND 45 TO 50 KT FLOW OVER ARL AND BRX AT H75 THROUGH MUCH
OF THAT TIME PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH MONDAY MORNING)

SNOW SHOWERS WILL CONTINUE TO DIMINISH THIS MORNING WITH GENERALLY
MVFR CONDITIONS PREVAILING ALONG I80...AND VFR FURTHER NORTH
ACROSS WESTERN NEBRASKA. A WARM FRONT WILL SLOWLY MOVE NORTHWARD
ACROSS THE AREA TONIGHT...BRINGING ANOTHER ROUND OF SNOW TO AREAS
ALONG I80. LOW MVFR TO IFR CIGS/VSBYS ARE LIKELY AFTER 06Z TONIGHT.
WINDS WILL GENERALLY BE LIGHT THROUGH THE TAF PERIOD BUT WILL
INCREASE OUT OF THE SOUTH LATE TONIGHT AND INTO EARLY MONDAY
MORNING.

&&

.FIRE WEATHER...
ISSUED AT 321 AM MST SUN MAR 1 2015

A WEAK UPPER LEVEL DISTURBANCE WILL PRODUCE LIGHT SNOW EARLY THIS
MORNING OVER FAR SOUTHEAST WYOMING AND SOUTHERN NEBRASKA PANHANDLE.
A LOW PRESSURE SYSTEM AND ASSOCIATED UPPER LEVEL TROUGH WILL APPROACH
FROM THE SOUTHWEST TONIGHT AND MONDAY...AND MOVE ACROSS THE CENTRAL
ROCKIES MONDAY NIGHT AND TUESDAY. SNOW WILL DEVELOP TONIGHT ACROSS
SOUTH CENTRAL WYOMING AND BECOME MORE WIDESPREAD MONDAY AND MONDAY
NIGHT. THE SNOW WILL BE HEAVY AT TIMES...ESPECIALLY OVER THE HIGHER
TERRAIN. THE SNOW WILL TAPER OFF TUESDAY NIGHT. A ARCTIC COLD FRONT
WILL PLUNGE SOUTH THROUGH THE DISTRICT MONDAY NIGHT. BITTERLY COLD
TEMPERATURES AND WIND CHILLS WILL PREVAIL TUESDAY THROUGH WEDNESDAY
BEFORE GRADUALLY MODERATING TEMPERATURES LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE TUESDAY NIGHT
     FOR WYZ111>114.

NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...MAJ
LONG TERM...CLH
AVIATION...TJT
FIRE WEATHER...MAJ



000
FXUS65 KCYS 011754
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1054 AM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 1055 AM MST SUN MAR 1 2015

NO CHANGES TO THE FORECAST TODAY. MAIN FOCUS REMAINS ON THE STORM
SYSTEM WHICH WILL MOVE ACROSS THE AREA TOMORROW AND TOMORROW
NIGHT. MODELS NOT IN GREAT AGREEMENT WITH WHERE THE HEAVIEST SNOW
WILL FALL...BUT THERE IS GENERAL CONSENSUS POINTS TO SOUTH
CENTRAL WYOMING. CURRENT WATER VAPOR AND RADAR OVER THE SOUTHWEST
CONUS SHOWING MOISTURE STREAMING NORTHEASTWARD FROM ARIZONA. SEEMS
REASONABLE THERE WILL BE WIDESPREAD SNOW ACROSS THE ENTIRE AREA BY
MONDAY NIGHT AS AN UPPER LEVEL DISTURBANCE MOVES FROM THE CENTRAL
ROCKIES INTO THE NORTHERN PLAINS.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 400 AM MST SUN MAR 1 2015

LATEST GOES WATER VAPOR IMAGERY SHOWED THE SPLIT CLOSED UPPER LOW
SLOWLY SINKING SOUTHEAST ALONG THE CENTRAL CA COAST. THE BASE OF
THE NORTHERN STREAM TROUGH WAS MOVING EAST ACROSS THE DAKOTAS. A
DEFORMATION ZONE STRETCHED NORTHEAST TO SOUTHWEST FROM WESTERN NE
ACROSS NORTHERN CO. NARROW BAND OF UPPER LIFT COMBINED WITH MOISTURE
AND WEAK UPSLOPE RESULTED IN AN AREA OF LIGHT SNOW OVER PORTIONS
OF SOUTHEAST WY AND WESTERN NE. HRRR MODEL PROGS THIS AREA TO WEAKEN
AS IT MOVES FURTHER EAST THROUGH DAYBREAK. TEMPERATURES WERE IN THE
SINGLE DIGITS AND TEENS WITH LIGHT WINDS.

FORECAST CONCERNS DURING THE SHORT TERM WILL FOCUS ON THE DEVELOPING
WINTER STORM AND ITS IMPACTS ON OUR AREA...PARTICULARLY FROM LATE
TONIGHT THROUGH TUESDAY. CLOSED UPPER LOW NEAR SOUTHERN CA COAST
GRADUALLY OPENS UP AND EJECTS NORTHEAST AS ANOTHER SHORTWAVE DROPS
SOUTH ALONG THE CA COAST DURING THE NEXT 24 TO 48 HOURS. THE MODEL
CONSENSUS PROGS A LOW PRESSURE SYSTEM TO FORM NEAR THE FOUR CORNERS
REGION AND TRACK NORTHEAST ACROSS COLORADO. LIGHT SNOW REDEVELOPS
LATER TODAY OVER THE SOUTHERN MOUNTAINS AND BECOMES MORE WIDESPREAD
AND HEAVIER LATE TONIGHT INTO MONDAY. THE GFS IS SLIGHTLY DEEPER
AND FASTER THAN THE ECMWF WITH REGARDS TO THE SURFACE LOW AND ITS
MOTION. THEY ARE SIMILAR WITH THE EASTWARD TRACK OF THE LOW INTO
THE CENTRAL PLAINS EARLY TUESDAY MORNING. THEY ALSO AGREE WITH THE
ARCTIC COLD FRONTAL PASSAGE DURING THIS TIME PERIOD. WINDS SHIFT
TO NORTHERLY AND BECOME GUSTY TUESDAY. SNOW WILL BE WIDESPREAD
OVER THE CWA MONDAY NIGHT AND TUESDAY. THE COMBINATION OF FALLING
AND BLOWING SNOW WILL RESULT IN HAZARDOUS TRAVEL WEST OF THE
LARAMIE RANGE...ESPECIALLY MONDAY THROUGH TUESDAY. LATEST WPC
GUIDANCE PROGS 1-2 FT OF SNOW FOR THE SNOWY/SIERRA MADRE RANGES
WITH UP TO A FOOT FOR THE NEARBY VALLEYS. ISSUED A WINTER STORM
WATCH FOR WY ZONES 111-114 LATE TONIGHT THROUGH LATE TUESDAY NIGHT
FOR THE POTENTIAL OF HEAVY SNOW. FURTHER NORTH AND EAST...WE`RE
LOOKING AT ADVISORY ACCUMULATIONS...GENERALLY 4-8 INCHES. THE
SOUTHERN LARAMIE RANGE COULD GET CLOSE TO A FOOT AS WELL. THE NEXT
SHIFT MAY UPGRADE AND/OR EXTEND THE WINTER HEADLINES AFTER LOOKING
AT THE 12Z/18Z MODEL GUIDANCE.

HIGHS TODAY WILL BE SIMILAR TO SATURDAY WITH MOSTLY UPPER TEENS TO
UPPER 20S. LOWS TONIGHT AND MONDAY NIGHT WILL AVERAGE IN THE TEENS.
MONDAY WILL BE MILDER WITH SOUTHWESTERLY WINDS. EXPECT HIGHS IN THE
30S TO AROUND 40. TEMPERATURES TUESDAY WILL NOT RISE MUCH FROM THE
EARLY MORNING LOWS...AND WILL BE FALLING THROUGH THE DAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM MST SUN MAR 1 2015

THE MAIN CHALLENGE IN THE EXTENDED WILL BE TEMPERATURE TRENDS AS WE
STILL ANTICIPATE A BAND OF NEW SNOWPACK SOMEWHERE IN THE CWA. GFS/EC
BOTH SHOW A SECONDARY SHORTWAVE DIVING ACROSS WY BETWEEN 00Z AND 12Z
WED. MODEST PVA SHOULD BE ENOUGH FOR SNOW SHOWERS TO LINGER INTO WED
MORNING OR PERHAPS EARLY AFTERNOON. MEDIUM RANGE 700-300 MILLIBAR RH
PROGS SUGGEST A DRYING COLUMN BY THIS TIME...SO EXPECT LESS THAN AN
INCH OF ADDITIONAL ACCUMULATION OVER THE LOWER ELEVATIONS AFTER 00Z
WED. TEMPERATURES WILL BE TRICKY ON TUE NIGHT AS CLOUDS WILL PREVENT
SIGNIFICANT RADIATIONAL COOLING. HOWEVER...MODELS AGREE WITH STRONG
LOW LEVEL COLD ADVECTION PUSHING H7 TEMPS AS LOW AS -20 DEG C BY 12Z
WED PER THE EURO. GIVEN AN AIR MASS THIS COLD...CONFIDENCE IS FAIRLY
HIGH THAT MANY AREAS WILL BE BELOW ZERO FOR LOWS. DID NOT STRAY TOO
FAR AWAY FROM GUIDANCE THOUGH. COOLEST TEMPERATURES ON WED SHOULD BE
FOUND OVER THE MOST SUBSTANTIAL SNOWPACK. GUIDANCE SUGGESTS THE BEST
CHANCE FOR LOW-ELEVATION SIGNIFICANT SNOWFALL EARLY IN THE WEEK WILL
BE WEST OF THE LARAMIE RANGE...SO UNDERCUT MOS BY SEVERAL DEGREES IN
THOSE AREAS. KEPT HIGHS BELOW GUIDANCE ACROSS THE BOARD WITH MUCH OF
THE AREA LIKELY TO RECEIVE ACCUMULATING SNOW IN THE SHORT TERM.

IMPROVING TEMPERATURES LATER IN THE WEEK AS UPPER-LEVEL RIDGING AND
LOW LEVEL DOWNSLOPE RETURN TO THE REGION. A BACK DOOR COLD FRONT IS
PROGGED TO SINK SOUTHWARD ON FRI AFTERNOON...POSSIBLY HAVING A SMALL
IMPACT ON HIGHS WITH COLD ADVECTION ALOFT. CANNOT RULE OUT ISOLATED
RAIN OR SNOW SHOWERS ON FRI NIGHT OR SAT MORNING WITH THE ARRIVAL OF
BETTER MID LEVEL SUPPORT. HOWEVER...KEPT THE FORECAST DRY FOR NOW AS
THIS SYSTEM LOOKS TO BE A BIT MOISTURE STARVED. STILL EXPECT A WINDY
PERIOD FROM WED NIGHT THROUGH FRI OVER THE WIND PRONE AREAS. THE GFS
HAS BEEN CONSISTENT WITH A STRONG H85 CAG-CPR GRADIENT IN EXCESS OF
60 METERS AND 45 TO 50 KT FLOW OVER ARL AND BRX AT H75 THROUGH MUCH
OF THAT TIME PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH MONDAY MORNING)

SNOW SHOWERS WILL CONTINUE TO DIMINISH THIS MORNING WITH GENERALLY
MVFR CONDITIONS PREVAILING ALONG I80...AND VFR FURTHER NORTH
ACROSS WESTERN NEBRASKA. A WARM FRONT WILL SLOWLY MOVE NORTHWARD
ACROSS THE AREA TONIGHT...BRINGING ANOTHER ROUND OF SNOW TO AREAS
ALONG I80. LOW MVFR TO IFR CIGS/VSBYS ARE LIKELY AFTER 06Z TONIGHT.
WINDS WILL GENERALLY BE LIGHT THROUGH THE TAF PERIOD BUT WILL
INCREASE OUT OF THE SOUTH LATE TONIGHT AND INTO EARLY MONDAY
MORNING.

&&

.FIRE WEATHER...
ISSUED AT 321 AM MST SUN MAR 1 2015

A WEAK UPPER LEVEL DISTURBANCE WILL PRODUCE LIGHT SNOW EARLY THIS
MORNING OVER FAR SOUTHEAST WYOMING AND SOUTHERN NEBRASKA PANHANDLE.
A LOW PRESSURE SYSTEM AND ASSOCIATED UPPER LEVEL TROUGH WILL APPROACH
FROM THE SOUTHWEST TONIGHT AND MONDAY...AND MOVE ACROSS THE CENTRAL
ROCKIES MONDAY NIGHT AND TUESDAY. SNOW WILL DEVELOP TONIGHT ACROSS
SOUTH CENTRAL WYOMING AND BECOME MORE WIDESPREAD MONDAY AND MONDAY
NIGHT. THE SNOW WILL BE HEAVY AT TIMES...ESPECIALLY OVER THE HIGHER
TERRAIN. THE SNOW WILL TAPER OFF TUESDAY NIGHT. A ARCTIC COLD FRONT
WILL PLUNGE SOUTH THROUGH THE DISTRICT MONDAY NIGHT. BITTERLY COLD
TEMPERATURES AND WIND CHILLS WILL PREVAIL TUESDAY THROUGH WEDNESDAY
BEFORE GRADUALLY MODERATING TEMPERATURES LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE TUESDAY NIGHT
     FOR WYZ111>114.

NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...MAJ
LONG TERM...CLH
AVIATION...TJT
FIRE WEATHER...MAJ




000
FXUS65 KCYS 011754
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1054 AM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 1055 AM MST SUN MAR 1 2015

NO CHANGES TO THE FORECAST TODAY. MAIN FOCUS REMAINS ON THE STORM
SYSTEM WHICH WILL MOVE ACROSS THE AREA TOMORROW AND TOMORROW
NIGHT. MODELS NOT IN GREAT AGREEMENT WITH WHERE THE HEAVIEST SNOW
WILL FALL...BUT THERE IS GENERAL CONSENSUS POINTS TO SOUTH
CENTRAL WYOMING. CURRENT WATER VAPOR AND RADAR OVER THE SOUTHWEST
CONUS SHOWING MOISTURE STREAMING NORTHEASTWARD FROM ARIZONA. SEEMS
REASONABLE THERE WILL BE WIDESPREAD SNOW ACROSS THE ENTIRE AREA BY
MONDAY NIGHT AS AN UPPER LEVEL DISTURBANCE MOVES FROM THE CENTRAL
ROCKIES INTO THE NORTHERN PLAINS.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 400 AM MST SUN MAR 1 2015

LATEST GOES WATER VAPOR IMAGERY SHOWED THE SPLIT CLOSED UPPER LOW
SLOWLY SINKING SOUTHEAST ALONG THE CENTRAL CA COAST. THE BASE OF
THE NORTHERN STREAM TROUGH WAS MOVING EAST ACROSS THE DAKOTAS. A
DEFORMATION ZONE STRETCHED NORTHEAST TO SOUTHWEST FROM WESTERN NE
ACROSS NORTHERN CO. NARROW BAND OF UPPER LIFT COMBINED WITH MOISTURE
AND WEAK UPSLOPE RESULTED IN AN AREA OF LIGHT SNOW OVER PORTIONS
OF SOUTHEAST WY AND WESTERN NE. HRRR MODEL PROGS THIS AREA TO WEAKEN
AS IT MOVES FURTHER EAST THROUGH DAYBREAK. TEMPERATURES WERE IN THE
SINGLE DIGITS AND TEENS WITH LIGHT WINDS.

FORECAST CONCERNS DURING THE SHORT TERM WILL FOCUS ON THE DEVELOPING
WINTER STORM AND ITS IMPACTS ON OUR AREA...PARTICULARLY FROM LATE
TONIGHT THROUGH TUESDAY. CLOSED UPPER LOW NEAR SOUTHERN CA COAST
GRADUALLY OPENS UP AND EJECTS NORTHEAST AS ANOTHER SHORTWAVE DROPS
SOUTH ALONG THE CA COAST DURING THE NEXT 24 TO 48 HOURS. THE MODEL
CONSENSUS PROGS A LOW PRESSURE SYSTEM TO FORM NEAR THE FOUR CORNERS
REGION AND TRACK NORTHEAST ACROSS COLORADO. LIGHT SNOW REDEVELOPS
LATER TODAY OVER THE SOUTHERN MOUNTAINS AND BECOMES MORE WIDESPREAD
AND HEAVIER LATE TONIGHT INTO MONDAY. THE GFS IS SLIGHTLY DEEPER
AND FASTER THAN THE ECMWF WITH REGARDS TO THE SURFACE LOW AND ITS
MOTION. THEY ARE SIMILAR WITH THE EASTWARD TRACK OF THE LOW INTO
THE CENTRAL PLAINS EARLY TUESDAY MORNING. THEY ALSO AGREE WITH THE
ARCTIC COLD FRONTAL PASSAGE DURING THIS TIME PERIOD. WINDS SHIFT
TO NORTHERLY AND BECOME GUSTY TUESDAY. SNOW WILL BE WIDESPREAD
OVER THE CWA MONDAY NIGHT AND TUESDAY. THE COMBINATION OF FALLING
AND BLOWING SNOW WILL RESULT IN HAZARDOUS TRAVEL WEST OF THE
LARAMIE RANGE...ESPECIALLY MONDAY THROUGH TUESDAY. LATEST WPC
GUIDANCE PROGS 1-2 FT OF SNOW FOR THE SNOWY/SIERRA MADRE RANGES
WITH UP TO A FOOT FOR THE NEARBY VALLEYS. ISSUED A WINTER STORM
WATCH FOR WY ZONES 111-114 LATE TONIGHT THROUGH LATE TUESDAY NIGHT
FOR THE POTENTIAL OF HEAVY SNOW. FURTHER NORTH AND EAST...WE`RE
LOOKING AT ADVISORY ACCUMULATIONS...GENERALLY 4-8 INCHES. THE
SOUTHERN LARAMIE RANGE COULD GET CLOSE TO A FOOT AS WELL. THE NEXT
SHIFT MAY UPGRADE AND/OR EXTEND THE WINTER HEADLINES AFTER LOOKING
AT THE 12Z/18Z MODEL GUIDANCE.

HIGHS TODAY WILL BE SIMILAR TO SATURDAY WITH MOSTLY UPPER TEENS TO
UPPER 20S. LOWS TONIGHT AND MONDAY NIGHT WILL AVERAGE IN THE TEENS.
MONDAY WILL BE MILDER WITH SOUTHWESTERLY WINDS. EXPECT HIGHS IN THE
30S TO AROUND 40. TEMPERATURES TUESDAY WILL NOT RISE MUCH FROM THE
EARLY MORNING LOWS...AND WILL BE FALLING THROUGH THE DAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM MST SUN MAR 1 2015

THE MAIN CHALLENGE IN THE EXTENDED WILL BE TEMPERATURE TRENDS AS WE
STILL ANTICIPATE A BAND OF NEW SNOWPACK SOMEWHERE IN THE CWA. GFS/EC
BOTH SHOW A SECONDARY SHORTWAVE DIVING ACROSS WY BETWEEN 00Z AND 12Z
WED. MODEST PVA SHOULD BE ENOUGH FOR SNOW SHOWERS TO LINGER INTO WED
MORNING OR PERHAPS EARLY AFTERNOON. MEDIUM RANGE 700-300 MILLIBAR RH
PROGS SUGGEST A DRYING COLUMN BY THIS TIME...SO EXPECT LESS THAN AN
INCH OF ADDITIONAL ACCUMULATION OVER THE LOWER ELEVATIONS AFTER 00Z
WED. TEMPERATURES WILL BE TRICKY ON TUE NIGHT AS CLOUDS WILL PREVENT
SIGNIFICANT RADIATIONAL COOLING. HOWEVER...MODELS AGREE WITH STRONG
LOW LEVEL COLD ADVECTION PUSHING H7 TEMPS AS LOW AS -20 DEG C BY 12Z
WED PER THE EURO. GIVEN AN AIR MASS THIS COLD...CONFIDENCE IS FAIRLY
HIGH THAT MANY AREAS WILL BE BELOW ZERO FOR LOWS. DID NOT STRAY TOO
FAR AWAY FROM GUIDANCE THOUGH. COOLEST TEMPERATURES ON WED SHOULD BE
FOUND OVER THE MOST SUBSTANTIAL SNOWPACK. GUIDANCE SUGGESTS THE BEST
CHANCE FOR LOW-ELEVATION SIGNIFICANT SNOWFALL EARLY IN THE WEEK WILL
BE WEST OF THE LARAMIE RANGE...SO UNDERCUT MOS BY SEVERAL DEGREES IN
THOSE AREAS. KEPT HIGHS BELOW GUIDANCE ACROSS THE BOARD WITH MUCH OF
THE AREA LIKELY TO RECEIVE ACCUMULATING SNOW IN THE SHORT TERM.

IMPROVING TEMPERATURES LATER IN THE WEEK AS UPPER-LEVEL RIDGING AND
LOW LEVEL DOWNSLOPE RETURN TO THE REGION. A BACK DOOR COLD FRONT IS
PROGGED TO SINK SOUTHWARD ON FRI AFTERNOON...POSSIBLY HAVING A SMALL
IMPACT ON HIGHS WITH COLD ADVECTION ALOFT. CANNOT RULE OUT ISOLATED
RAIN OR SNOW SHOWERS ON FRI NIGHT OR SAT MORNING WITH THE ARRIVAL OF
BETTER MID LEVEL SUPPORT. HOWEVER...KEPT THE FORECAST DRY FOR NOW AS
THIS SYSTEM LOOKS TO BE A BIT MOISTURE STARVED. STILL EXPECT A WINDY
PERIOD FROM WED NIGHT THROUGH FRI OVER THE WIND PRONE AREAS. THE GFS
HAS BEEN CONSISTENT WITH A STRONG H85 CAG-CPR GRADIENT IN EXCESS OF
60 METERS AND 45 TO 50 KT FLOW OVER ARL AND BRX AT H75 THROUGH MUCH
OF THAT TIME PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH MONDAY MORNING)

SNOW SHOWERS WILL CONTINUE TO DIMINISH THIS MORNING WITH GENERALLY
MVFR CONDITIONS PREVAILING ALONG I80...AND VFR FURTHER NORTH
ACROSS WESTERN NEBRASKA. A WARM FRONT WILL SLOWLY MOVE NORTHWARD
ACROSS THE AREA TONIGHT...BRINGING ANOTHER ROUND OF SNOW TO AREAS
ALONG I80. LOW MVFR TO IFR CIGS/VSBYS ARE LIKELY AFTER 06Z TONIGHT.
WINDS WILL GENERALLY BE LIGHT THROUGH THE TAF PERIOD BUT WILL
INCREASE OUT OF THE SOUTH LATE TONIGHT AND INTO EARLY MONDAY
MORNING.

&&

.FIRE WEATHER...
ISSUED AT 321 AM MST SUN MAR 1 2015

A WEAK UPPER LEVEL DISTURBANCE WILL PRODUCE LIGHT SNOW EARLY THIS
MORNING OVER FAR SOUTHEAST WYOMING AND SOUTHERN NEBRASKA PANHANDLE.
A LOW PRESSURE SYSTEM AND ASSOCIATED UPPER LEVEL TROUGH WILL APPROACH
FROM THE SOUTHWEST TONIGHT AND MONDAY...AND MOVE ACROSS THE CENTRAL
ROCKIES MONDAY NIGHT AND TUESDAY. SNOW WILL DEVELOP TONIGHT ACROSS
SOUTH CENTRAL WYOMING AND BECOME MORE WIDESPREAD MONDAY AND MONDAY
NIGHT. THE SNOW WILL BE HEAVY AT TIMES...ESPECIALLY OVER THE HIGHER
TERRAIN. THE SNOW WILL TAPER OFF TUESDAY NIGHT. A ARCTIC COLD FRONT
WILL PLUNGE SOUTH THROUGH THE DISTRICT MONDAY NIGHT. BITTERLY COLD
TEMPERATURES AND WIND CHILLS WILL PREVAIL TUESDAY THROUGH WEDNESDAY
BEFORE GRADUALLY MODERATING TEMPERATURES LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE TUESDAY NIGHT
     FOR WYZ111>114.

NE...NONE.
&&

$$

UPDATE...SML
SHORT TERM...MAJ
LONG TERM...CLH
AVIATION...TJT
FIRE WEATHER...MAJ



000
FXUS63 KUNR 011728
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1028 AM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 836 AM MST SUN MAR 1 2015

UPPER WAVE PASSING THROUGH EASTERN MT/WESTERN DAKOTAS IS PRODUCING
SOME SNOW SHOWERS ACROSS THE WYOMING BLACK HILLS AND AREAS
NORTHWEST OF THE CWA. HULETT IS REPORTING REDUCED
VISIBILITIES...SO ADDED SOME ISOLATED SNOW SHOWERS TO THE NORTHERN
HILLS. ALSO ADDED SOME SCATTERED FLURRIES ACROSS NORTHWEST SD
TODAY. UPDATED SKY GRIDS TO MATCH POPS/WX...BUT REST OF FORECAST
LOOKS ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 237 AM MST SUN MAR 1 2015

NW FLOW WILL PREVAIL IN THE PERIOD WITH A STRONG
PHASING SYSTEM ON TRACK MONDAY INTO TUES. A STRONG NW FLOW UPPER
LEVEL TROUGH WILL MERGE WITH THE EJECTING SW CONUS UPPER LEVEL
TROUGH...HELPING TO FORCE OF PERIOD OF LONG TRAJECTORY NORTHERLY
FLOW. THIS WILL SUPPORT ANOTHER ROUND OF ARCTIC AIR INTO THE
CONUS...ALONG WITH SOME SNOW AND WIND LOCALLY. A WEAKER SHORTWAVE
WILL TRAVERSE THE NORTHERN PLAINS TODAY...SUPPORTING REINFORCING
COLD THERMAL FIELDS. LACK OF MOISTURE WITH LARGE SCALE SINK
LOCALLY...EXPECTED TO SUPPORT DRY CONDS IN THE FA. INCREASING RETURN
FLOW FORCED BY SHORTWAVE RIDGING AHEAD OF THE APPROACHING STRONGER
NW FLOW IMPULSE...WILL SUPPORT A WARMER DAY MONDAY WITH CONTINUED
DRY CONDS...BEFORE SNOW AND WIND RETURN TO THE REGION MONDAY NIGHT.

TODAY...ANOTHER NW FLOW IMPULSE EXPECTED INTO THE REGION. ALTHOUGH
MOST IF NOT ALL OF THE LSA/UVM WILL PASS NORTH OF THE FA...CANNOT
RULE OUT A FEW HIGH BASED SNOW SHOWERS OVER THE NORTH HALF OF THE FA
AND OVER THE BLACK HILLS GIVEN FAIRLY STEEP LL LAPSE RATES.
HOWEVER...GIVEN DRY PROFILES...VIRGA WOULD BE ANTICIPATED THUS NO
POPS WARRANTED. STEEP LL LAPSE RATES PER INSOLATION AND MIXING WILL
FORCE FASTER FLOW DOWN SUPPORTING BREEZY CONDS...ESP ON THE SD
PLAINS WITH 15 TO 25 MPH WINDS EXPECTED. THERMAL FIELDS WILL
BASICALLY SEE NEAR NEUTRAL TEMP ADV...WITH TEMPS SIMILAR TO SAT/S
NUMBERS...SLIGHTLY WARMER. ASSOCIATED SFC HIGH WILL SHIFT SE OF THE
REGION TONIGHT...WITH GUSTY SOUTHERLY RETURN FLOW DEVELOPING OVER NE
WY AND PORTIONS OF THE SD PLAINS.

MONDAY...RETURN FLOW WILL REV UP WITH SOUTHERLY WINDS INCREASING
THROUGH THE DAY. WAA WILL BE ONGOING WITH MOST LOCATIONS SEEING 40S
FOR HIGHS...POSSIBLY NEAR 50 IN THE LEE OF THE BLACK HILLS. STRONG
NW FLOW UPPER TROUGH AND THE EJECTING SW CONUS UPPER LOW WILL
SUPPORT INCREASING LARGE SCALE ASCENT ACROSS THE SOUTHERN HALF OF
THE FA MONDAY EVENING WITH INCREASING MOISTURE AND FORCING
SUPPORTING INCREASING CHANCES FOR SNOW. BETTER CHANCES WILL ARRIVE
LATER MONDAY NIGHT AS A STRONG COLD FRONT IS FORCED THROUGH THE
FA...SUPPORTING INCREASING FGEN ACROSS MOST OF THE FA...ESP THE
SOUTHERN THIRD. DECENT LL MOISTURE COUPLED WITH MODEST FORCING WILL
AT LEAST SUPPORT UP TO A COUPLE INCHES OF SNOW ACROSS SCENTRAL
SD...WITH LESSER AMOUNTS OUTSIDE OF THE NORTHERN BLACK HILLS.
INCREASING FLOW WITH SUFFICIENT LL MOISTURE AND FORCING IN THE DGZ
WILL SUPPORT A GOOD PERIOD OF UPSLOPE IN THE NORTHERN HILLS WITH A
FEW INCHES POSSIBLE THERE BY TUE MORNING. STRONG CAA COUPLED WITH
FAST LL MOMENTUM WILL SUPPORT STRONG GUSTY WINDS NW WINDS ON THE SD
PLAINS EARLY TUES MORNING. ALTHOUGH SNOW AMOUNTS LOOK MINIMAL ON
THE PLAINS...BLOWING SNOW AND HAZARDOUS TRAVEL IS A CONCERN AND
WILL CERTAINLY NEED TO BE MONITORED WITH FUTURE FORECAST PACKAGES.
VERY COLD AIR WILL BEGIN TO ADVECT INTO THE REGION EARLY TUE MORNING
OVER THE NW HALF...WITH WINDCHILLS FALLING BELOW ZERO BY DAWN MOST
PLACES THERE.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 237 AM MST SUN MAR 1 2015

ARCTIC HIGH PRESSURE CONTINUES TO SURGE INTO THE NORTHERN PLAINS ON
TUESDAY...WITH STRONG NORTHWESTERLY WINDS PERSISTING THROUGH MUCH OF
THE DAY...AND TEMPERATURES STEADY OR CONTINUING TO FALL INTO THE
EVENING. LIGHT SNOW WILL BE LIKELY FROM NORTHEAST WYOMING THROUGH
SOUTHERN SOUTH DAKOTA...WITH SNOWFALL DIMINISHING FROM NORTH TO
SOUTH DURING THE DAY. TEMPERATURES WILL FALL BELOW ZERO ACROSS MUCH
OF THE AREA TUESDAY NIGHT.

THE BITTER COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP
IS EXPECTED. THIS NEXT WARM UP...HOWEVER...LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1025 AM MST SUN MAR 1 2015

ISOLATED SNOW SHOWERS POSSIBLE FAR NORTHWEST SOUTH DAKOTA AND OVER
BLACK HILLS THROUGH THIS AFTERNOON..WITH LCL MVFR CIGS/IFR VSBY.
OTHERWISE VFR CONDITIONS EXPECTED THROUGH MONDAY MORNING.


&&

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

$$

UPDATE...POJORLIE
SHORT TERM...JC
LONG TERM...15
AVIATION...7






000
FXUS63 KUNR 011728
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
1028 AM MST SUN MAR 1 2015

.UPDATE...
ISSUED AT 836 AM MST SUN MAR 1 2015

UPPER WAVE PASSING THROUGH EASTERN MT/WESTERN DAKOTAS IS PRODUCING
SOME SNOW SHOWERS ACROSS THE WYOMING BLACK HILLS AND AREAS
NORTHWEST OF THE CWA. HULETT IS REPORTING REDUCED
VISIBILITIES...SO ADDED SOME ISOLATED SNOW SHOWERS TO THE NORTHERN
HILLS. ALSO ADDED SOME SCATTERED FLURRIES ACROSS NORTHWEST SD
TODAY. UPDATED SKY GRIDS TO MATCH POPS/WX...BUT REST OF FORECAST
LOOKS ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 237 AM MST SUN MAR 1 2015

NW FLOW WILL PREVAIL IN THE PERIOD WITH A STRONG
PHASING SYSTEM ON TRACK MONDAY INTO TUES. A STRONG NW FLOW UPPER
LEVEL TROUGH WILL MERGE WITH THE EJECTING SW CONUS UPPER LEVEL
TROUGH...HELPING TO FORCE OF PERIOD OF LONG TRAJECTORY NORTHERLY
FLOW. THIS WILL SUPPORT ANOTHER ROUND OF ARCTIC AIR INTO THE
CONUS...ALONG WITH SOME SNOW AND WIND LOCALLY. A WEAKER SHORTWAVE
WILL TRAVERSE THE NORTHERN PLAINS TODAY...SUPPORTING REINFORCING
COLD THERMAL FIELDS. LACK OF MOISTURE WITH LARGE SCALE SINK
LOCALLY...EXPECTED TO SUPPORT DRY CONDS IN THE FA. INCREASING RETURN
FLOW FORCED BY SHORTWAVE RIDGING AHEAD OF THE APPROACHING STRONGER
NW FLOW IMPULSE...WILL SUPPORT A WARMER DAY MONDAY WITH CONTINUED
DRY CONDS...BEFORE SNOW AND WIND RETURN TO THE REGION MONDAY NIGHT.

TODAY...ANOTHER NW FLOW IMPULSE EXPECTED INTO THE REGION. ALTHOUGH
MOST IF NOT ALL OF THE LSA/UVM WILL PASS NORTH OF THE FA...CANNOT
RULE OUT A FEW HIGH BASED SNOW SHOWERS OVER THE NORTH HALF OF THE FA
AND OVER THE BLACK HILLS GIVEN FAIRLY STEEP LL LAPSE RATES.
HOWEVER...GIVEN DRY PROFILES...VIRGA WOULD BE ANTICIPATED THUS NO
POPS WARRANTED. STEEP LL LAPSE RATES PER INSOLATION AND MIXING WILL
FORCE FASTER FLOW DOWN SUPPORTING BREEZY CONDS...ESP ON THE SD
PLAINS WITH 15 TO 25 MPH WINDS EXPECTED. THERMAL FIELDS WILL
BASICALLY SEE NEAR NEUTRAL TEMP ADV...WITH TEMPS SIMILAR TO SAT/S
NUMBERS...SLIGHTLY WARMER. ASSOCIATED SFC HIGH WILL SHIFT SE OF THE
REGION TONIGHT...WITH GUSTY SOUTHERLY RETURN FLOW DEVELOPING OVER NE
WY AND PORTIONS OF THE SD PLAINS.

MONDAY...RETURN FLOW WILL REV UP WITH SOUTHERLY WINDS INCREASING
THROUGH THE DAY. WAA WILL BE ONGOING WITH MOST LOCATIONS SEEING 40S
FOR HIGHS...POSSIBLY NEAR 50 IN THE LEE OF THE BLACK HILLS. STRONG
NW FLOW UPPER TROUGH AND THE EJECTING SW CONUS UPPER LOW WILL
SUPPORT INCREASING LARGE SCALE ASCENT ACROSS THE SOUTHERN HALF OF
THE FA MONDAY EVENING WITH INCREASING MOISTURE AND FORCING
SUPPORTING INCREASING CHANCES FOR SNOW. BETTER CHANCES WILL ARRIVE
LATER MONDAY NIGHT AS A STRONG COLD FRONT IS FORCED THROUGH THE
FA...SUPPORTING INCREASING FGEN ACROSS MOST OF THE FA...ESP THE
SOUTHERN THIRD. DECENT LL MOISTURE COUPLED WITH MODEST FORCING WILL
AT LEAST SUPPORT UP TO A COUPLE INCHES OF SNOW ACROSS SCENTRAL
SD...WITH LESSER AMOUNTS OUTSIDE OF THE NORTHERN BLACK HILLS.
INCREASING FLOW WITH SUFFICIENT LL MOISTURE AND FORCING IN THE DGZ
WILL SUPPORT A GOOD PERIOD OF UPSLOPE IN THE NORTHERN HILLS WITH A
FEW INCHES POSSIBLE THERE BY TUE MORNING. STRONG CAA COUPLED WITH
FAST LL MOMENTUM WILL SUPPORT STRONG GUSTY WINDS NW WINDS ON THE SD
PLAINS EARLY TUES MORNING. ALTHOUGH SNOW AMOUNTS LOOK MINIMAL ON
THE PLAINS...BLOWING SNOW AND HAZARDOUS TRAVEL IS A CONCERN AND
WILL CERTAINLY NEED TO BE MONITORED WITH FUTURE FORECAST PACKAGES.
VERY COLD AIR WILL BEGIN TO ADVECT INTO THE REGION EARLY TUE MORNING
OVER THE NW HALF...WITH WINDCHILLS FALLING BELOW ZERO BY DAWN MOST
PLACES THERE.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 237 AM MST SUN MAR 1 2015

ARCTIC HIGH PRESSURE CONTINUES TO SURGE INTO THE NORTHERN PLAINS ON
TUESDAY...WITH STRONG NORTHWESTERLY WINDS PERSISTING THROUGH MUCH OF
THE DAY...AND TEMPERATURES STEADY OR CONTINUING TO FALL INTO THE
EVENING. LIGHT SNOW WILL BE LIKELY FROM NORTHEAST WYOMING THROUGH
SOUTHERN SOUTH DAKOTA...WITH SNOWFALL DIMINISHING FROM NORTH TO
SOUTH DURING THE DAY. TEMPERATURES WILL FALL BELOW ZERO ACROSS MUCH
OF THE AREA TUESDAY NIGHT.

THE BITTER COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP
IS EXPECTED. THIS NEXT WARM UP...HOWEVER...LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1025 AM MST SUN MAR 1 2015

ISOLATED SNOW SHOWERS POSSIBLE FAR NORTHWEST SOUTH DAKOTA AND OVER
BLACK HILLS THROUGH THIS AFTERNOON..WITH LCL MVFR CIGS/IFR VSBY.
OTHERWISE VFR CONDITIONS EXPECTED THROUGH MONDAY MORNING.


&&

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

$$

UPDATE...POJORLIE
SHORT TERM...JC
LONG TERM...15
AVIATION...7







000
FXUS63 KUNR 011544
AFDUNR

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

.UPDATE...
ISSUED AT 836 AM MST SUN MAR 1 2015

UPPER WAVE PASSING THROUGH EASTERN MT/WESTERN DAKOTAS IS PRODUCING
SOME SNOW SHOWERS ACROSS THE WYOMING BLACK HILLS AND AREAS
NORTHWEST OF THE CWA. HULETT IS REPORTING REDUCED
VISIBILITIES...SO ADDED SOME ISOLATED SNOW SHOWERS TO THE NORTHERN
HILLS. ALSO ADDED SOME SCATTERED FLURRIES ACROSS NORTHWEST SD
TODAY. UPDATED SKY GRIDS TO MATCH POPS/WX...BUT REST OF FORECAST
LOOKS ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 237 AM MST SUN MAR 1 2015

NW FLOW WILL PREVAIL IN THE PERIOD WITH A STRONG
PHASING SYSTEM ON TRACK MONDAY INTO TUES. A STRONG NW FLOW UPPER
LEVEL TROUGH WILL MERGE WITH THE EJECTING SW CONUS UPPER LEVEL
TROUGH...HELPING TO FORCE OF PERIOD OF LONG TRAJECTORY NORTHERLY
FLOW. THIS WILL SUPPORT ANOTHER ROUND OF ARCTIC AIR INTO THE
CONUS...ALONG WITH SOME SNOW AND WIND LOCALLY. A WEAKER SHORTWAVE
WILL TRAVERSE THE NORTHERN PLAINS TODAY...SUPPORTING REINFORCING
COLD THERMAL FIELDS. LACK OF MOISTURE WITH LARGE SCALE SINK
LOCALLY...EXPECTED TO SUPPORT DRY CONDS IN THE FA. INCREASING RETURN
FLOW FORCED BY SHORTWAVE RIDGING AHEAD OF THE APPROACHING STRONGER
NW FLOW IMPULSE...WILL SUPPORT A WARMER DAY MONDAY WITH CONTINUED
DRY CONDS...BEFORE SNOW AND WIND RETURN TO THE REGION MONDAY NIGHT.

TODAY...ANOTHER NW FLOW IMPULSE EXPECTED INTO THE REGION. ALTHOUGH
MOST IF NOT ALL OF THE LSA/UVM WILL PASS NORTH OF THE FA...CANNOT
RULE OUT A FEW HIGH BASED SNOW SHOWERS OVER THE NORTH HALF OF THE FA
AND OVER THE BLACK HILLS GIVEN FAIRLY STEEP LL LAPSE RATES.
HOWEVER...GIVEN DRY PROFILES...VIRGA WOULD BE ANTICIPATED THUS NO
POPS WARRANTED. STEEP LL LAPSE RATES PER INSOLATION AND MIXING WILL
FORCE FASTER FLOW DOWN SUPPORTING BREEZY CONDS...ESP ON THE SD
PLAINS WITH 15 TO 25 MPH WINDS EXPECTED. THERMAL FIELDS WILL
BASICALLY SEE NEAR NEUTRAL TEMP ADV...WITH TEMPS SIMILAR TO SAT/S
NUMBERS...SLIGHTLY WARMER. ASSOCIATED SFC HIGH WILL SHIFT SE OF THE
REGION TONIGHT...WITH GUSTY SOUTHERLY RETURN FLOW DEVELOPING OVER NE
WY AND PORTIONS OF THE SD PLAINS.

MONDAY...RETURN FLOW WILL REV UP WITH SOUTHERLY WINDS INCREASING
THROUGH THE DAY. WAA WILL BE ONGOING WITH MOST LOCATIONS SEEING 40S
FOR HIGHS...POSSIBLY NEAR 50 IN THE LEE OF THE BLACK HILLS. STRONG
NW FLOW UPPER TROUGH AND THE EJECTING SW CONUS UPPER LOW WILL
SUPPORT INCREASING LARGE SCALE ASCENT ACROSS THE SOUTHERN HALF OF
THE FA MONDAY EVENING WITH INCREASING MOISTURE AND FORCING
SUPPORTING INCREASING CHANCES FOR SNOW. BETTER CHANCES WILL ARRIVE
LATER MONDAY NIGHT AS A STRONG COLD FRONT IS FORCED THROUGH THE
FA...SUPPORTING INCREASING FGEN ACROSS MOST OF THE FA...ESP THE
SOUTHERN THIRD. DECENT LL MOISTURE COUPLED WITH MODEST FORCING WILL
AT LEAST SUPPORT UP TO A COUPLE INCHES OF SNOW ACROSS SCENTRAL
SD...WITH LESSER AMOUNTS OUTSIDE OF THE NORTHERN BLACK HILLS.
INCREASING FLOW WITH SUFFICIENT LL MOISTURE AND FORCING IN THE DGZ
WILL SUPPORT A GOOD PERIOD OF UPSLOPE IN THE NORTHERN HILLS WITH A
FEW INCHES POSSIBLE THERE BY TUE MORNING. STRONG CAA COUPLED WITH
FAST LL MOMENTUM WILL SUPPORT STRONG GUSTY WINDS NW WINDS ON THE SD
PLAINS EARLY TUES MORNING. ALTHOUGH SNOW AMOUNTS LOOK MINIMAL ON
THE PLAINS...BLOWING SNOW AND HAZARDOUS TRAVEL IS A CONCERN AND
WILL CERTAINLY NEED TO BE MONITORED WITH FUTURE FORECAST PACKAGES.
VERY COLD AIR WILL BEGIN TO ADVECT INTO THE REGION EARLY TUE MORNING
OVER THE NW HALF...WITH WINDCHILLS FALLING BELOW ZERO BY DAWN MOST
PLACES THERE.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 237 AM MST SUN MAR 1 2015

ARCTIC HIGH PRESSURE CONTINUES TO SURGE INTO THE NORTHERN PLAINS ON
TUESDAY...WITH STRONG NORTHWESTERLY WINDS PERSISTING THROUGH MUCH OF
THE DAY...AND TEMPERATURES STEADY OR CONTINUING TO FALL INTO THE
EVENING. LIGHT SNOW WILL BE LIKELY FROM NORTHEAST WYOMING THROUGH
SOUTHERN SOUTH DAKOTA...WITH SNOWFALL DIMINISHING FROM NORTH TO
SOUTH DURING THE DAY. TEMPERATURES WILL FALL BELOW ZERO ACROSS MUCH
OF THE AREA TUESDAY NIGHT.

THE BITTER COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP
IS EXPECTED. THIS NEXT WARM UP...HOWEVER...LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 237 AM MST SUN MAR 1 2015

LCL MVFR CIGS WILL BE POSSIBLE ACROSS NORTHEAST WYOMING AND THE
BLACK HILLS AREA THROUGH 18Z. OTHERWISE...VFR CONDITIONS ARE
EXPECTED THROUGH MONDAY MORNING.


&&

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

$$

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







000
FXUS63 KUNR 011544
AFDUNR

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

.UPDATE...
ISSUED AT 836 AM MST SUN MAR 1 2015

UPPER WAVE PASSING THROUGH EASTERN MT/WESTERN DAKOTAS IS PRODUCING
SOME SNOW SHOWERS ACROSS THE WYOMING BLACK HILLS AND AREAS
NORTHWEST OF THE CWA. HULETT IS REPORTING REDUCED
VISIBILITIES...SO ADDED SOME ISOLATED SNOW SHOWERS TO THE NORTHERN
HILLS. ALSO ADDED SOME SCATTERED FLURRIES ACROSS NORTHWEST SD
TODAY. UPDATED SKY GRIDS TO MATCH POPS/WX...BUT REST OF FORECAST
LOOKS ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 237 AM MST SUN MAR 1 2015

NW FLOW WILL PREVAIL IN THE PERIOD WITH A STRONG
PHASING SYSTEM ON TRACK MONDAY INTO TUES. A STRONG NW FLOW UPPER
LEVEL TROUGH WILL MERGE WITH THE EJECTING SW CONUS UPPER LEVEL
TROUGH...HELPING TO FORCE OF PERIOD OF LONG TRAJECTORY NORTHERLY
FLOW. THIS WILL SUPPORT ANOTHER ROUND OF ARCTIC AIR INTO THE
CONUS...ALONG WITH SOME SNOW AND WIND LOCALLY. A WEAKER SHORTWAVE
WILL TRAVERSE THE NORTHERN PLAINS TODAY...SUPPORTING REINFORCING
COLD THERMAL FIELDS. LACK OF MOISTURE WITH LARGE SCALE SINK
LOCALLY...EXPECTED TO SUPPORT DRY CONDS IN THE FA. INCREASING RETURN
FLOW FORCED BY SHORTWAVE RIDGING AHEAD OF THE APPROACHING STRONGER
NW FLOW IMPULSE...WILL SUPPORT A WARMER DAY MONDAY WITH CONTINUED
DRY CONDS...BEFORE SNOW AND WIND RETURN TO THE REGION MONDAY NIGHT.

TODAY...ANOTHER NW FLOW IMPULSE EXPECTED INTO THE REGION. ALTHOUGH
MOST IF NOT ALL OF THE LSA/UVM WILL PASS NORTH OF THE FA...CANNOT
RULE OUT A FEW HIGH BASED SNOW SHOWERS OVER THE NORTH HALF OF THE FA
AND OVER THE BLACK HILLS GIVEN FAIRLY STEEP LL LAPSE RATES.
HOWEVER...GIVEN DRY PROFILES...VIRGA WOULD BE ANTICIPATED THUS NO
POPS WARRANTED. STEEP LL LAPSE RATES PER INSOLATION AND MIXING WILL
FORCE FASTER FLOW DOWN SUPPORTING BREEZY CONDS...ESP ON THE SD
PLAINS WITH 15 TO 25 MPH WINDS EXPECTED. THERMAL FIELDS WILL
BASICALLY SEE NEAR NEUTRAL TEMP ADV...WITH TEMPS SIMILAR TO SAT/S
NUMBERS...SLIGHTLY WARMER. ASSOCIATED SFC HIGH WILL SHIFT SE OF THE
REGION TONIGHT...WITH GUSTY SOUTHERLY RETURN FLOW DEVELOPING OVER NE
WY AND PORTIONS OF THE SD PLAINS.

MONDAY...RETURN FLOW WILL REV UP WITH SOUTHERLY WINDS INCREASING
THROUGH THE DAY. WAA WILL BE ONGOING WITH MOST LOCATIONS SEEING 40S
FOR HIGHS...POSSIBLY NEAR 50 IN THE LEE OF THE BLACK HILLS. STRONG
NW FLOW UPPER TROUGH AND THE EJECTING SW CONUS UPPER LOW WILL
SUPPORT INCREASING LARGE SCALE ASCENT ACROSS THE SOUTHERN HALF OF
THE FA MONDAY EVENING WITH INCREASING MOISTURE AND FORCING
SUPPORTING INCREASING CHANCES FOR SNOW. BETTER CHANCES WILL ARRIVE
LATER MONDAY NIGHT AS A STRONG COLD FRONT IS FORCED THROUGH THE
FA...SUPPORTING INCREASING FGEN ACROSS MOST OF THE FA...ESP THE
SOUTHERN THIRD. DECENT LL MOISTURE COUPLED WITH MODEST FORCING WILL
AT LEAST SUPPORT UP TO A COUPLE INCHES OF SNOW ACROSS SCENTRAL
SD...WITH LESSER AMOUNTS OUTSIDE OF THE NORTHERN BLACK HILLS.
INCREASING FLOW WITH SUFFICIENT LL MOISTURE AND FORCING IN THE DGZ
WILL SUPPORT A GOOD PERIOD OF UPSLOPE IN THE NORTHERN HILLS WITH A
FEW INCHES POSSIBLE THERE BY TUE MORNING. STRONG CAA COUPLED WITH
FAST LL MOMENTUM WILL SUPPORT STRONG GUSTY WINDS NW WINDS ON THE SD
PLAINS EARLY TUES MORNING. ALTHOUGH SNOW AMOUNTS LOOK MINIMAL ON
THE PLAINS...BLOWING SNOW AND HAZARDOUS TRAVEL IS A CONCERN AND
WILL CERTAINLY NEED TO BE MONITORED WITH FUTURE FORECAST PACKAGES.
VERY COLD AIR WILL BEGIN TO ADVECT INTO THE REGION EARLY TUE MORNING
OVER THE NW HALF...WITH WINDCHILLS FALLING BELOW ZERO BY DAWN MOST
PLACES THERE.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 237 AM MST SUN MAR 1 2015

ARCTIC HIGH PRESSURE CONTINUES TO SURGE INTO THE NORTHERN PLAINS ON
TUESDAY...WITH STRONG NORTHWESTERLY WINDS PERSISTING THROUGH MUCH OF
THE DAY...AND TEMPERATURES STEADY OR CONTINUING TO FALL INTO THE
EVENING. LIGHT SNOW WILL BE LIKELY FROM NORTHEAST WYOMING THROUGH
SOUTHERN SOUTH DAKOTA...WITH SNOWFALL DIMINISHING FROM NORTH TO
SOUTH DURING THE DAY. TEMPERATURES WILL FALL BELOW ZERO ACROSS MUCH
OF THE AREA TUESDAY NIGHT.

THE BITTER COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP
IS EXPECTED. THIS NEXT WARM UP...HOWEVER...LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 237 AM MST SUN MAR 1 2015

LCL MVFR CIGS WILL BE POSSIBLE ACROSS NORTHEAST WYOMING AND THE
BLACK HILLS AREA THROUGH 18Z. OTHERWISE...VFR CONDITIONS ARE
EXPECTED THROUGH MONDAY MORNING.


&&

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

$$

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







000
FXUS63 KUNR 011544
AFDUNR

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

.UPDATE...
ISSUED AT 836 AM MST SUN MAR 1 2015

UPPER WAVE PASSING THROUGH EASTERN MT/WESTERN DAKOTAS IS PRODUCING
SOME SNOW SHOWERS ACROSS THE WYOMING BLACK HILLS AND AREAS
NORTHWEST OF THE CWA. HULETT IS REPORTING REDUCED
VISIBILITIES...SO ADDED SOME ISOLATED SNOW SHOWERS TO THE NORTHERN
HILLS. ALSO ADDED SOME SCATTERED FLURRIES ACROSS NORTHWEST SD
TODAY. UPDATED SKY GRIDS TO MATCH POPS/WX...BUT REST OF FORECAST
LOOKS ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 237 AM MST SUN MAR 1 2015

NW FLOW WILL PREVAIL IN THE PERIOD WITH A STRONG
PHASING SYSTEM ON TRACK MONDAY INTO TUES. A STRONG NW FLOW UPPER
LEVEL TROUGH WILL MERGE WITH THE EJECTING SW CONUS UPPER LEVEL
TROUGH...HELPING TO FORCE OF PERIOD OF LONG TRAJECTORY NORTHERLY
FLOW. THIS WILL SUPPORT ANOTHER ROUND OF ARCTIC AIR INTO THE
CONUS...ALONG WITH SOME SNOW AND WIND LOCALLY. A WEAKER SHORTWAVE
WILL TRAVERSE THE NORTHERN PLAINS TODAY...SUPPORTING REINFORCING
COLD THERMAL FIELDS. LACK OF MOISTURE WITH LARGE SCALE SINK
LOCALLY...EXPECTED TO SUPPORT DRY CONDS IN THE FA. INCREASING RETURN
FLOW FORCED BY SHORTWAVE RIDGING AHEAD OF THE APPROACHING STRONGER
NW FLOW IMPULSE...WILL SUPPORT A WARMER DAY MONDAY WITH CONTINUED
DRY CONDS...BEFORE SNOW AND WIND RETURN TO THE REGION MONDAY NIGHT.

TODAY...ANOTHER NW FLOW IMPULSE EXPECTED INTO THE REGION. ALTHOUGH
MOST IF NOT ALL OF THE LSA/UVM WILL PASS NORTH OF THE FA...CANNOT
RULE OUT A FEW HIGH BASED SNOW SHOWERS OVER THE NORTH HALF OF THE FA
AND OVER THE BLACK HILLS GIVEN FAIRLY STEEP LL LAPSE RATES.
HOWEVER...GIVEN DRY PROFILES...VIRGA WOULD BE ANTICIPATED THUS NO
POPS WARRANTED. STEEP LL LAPSE RATES PER INSOLATION AND MIXING WILL
FORCE FASTER FLOW DOWN SUPPORTING BREEZY CONDS...ESP ON THE SD
PLAINS WITH 15 TO 25 MPH WINDS EXPECTED. THERMAL FIELDS WILL
BASICALLY SEE NEAR NEUTRAL TEMP ADV...WITH TEMPS SIMILAR TO SAT/S
NUMBERS...SLIGHTLY WARMER. ASSOCIATED SFC HIGH WILL SHIFT SE OF THE
REGION TONIGHT...WITH GUSTY SOUTHERLY RETURN FLOW DEVELOPING OVER NE
WY AND PORTIONS OF THE SD PLAINS.

MONDAY...RETURN FLOW WILL REV UP WITH SOUTHERLY WINDS INCREASING
THROUGH THE DAY. WAA WILL BE ONGOING WITH MOST LOCATIONS SEEING 40S
FOR HIGHS...POSSIBLY NEAR 50 IN THE LEE OF THE BLACK HILLS. STRONG
NW FLOW UPPER TROUGH AND THE EJECTING SW CONUS UPPER LOW WILL
SUPPORT INCREASING LARGE SCALE ASCENT ACROSS THE SOUTHERN HALF OF
THE FA MONDAY EVENING WITH INCREASING MOISTURE AND FORCING
SUPPORTING INCREASING CHANCES FOR SNOW. BETTER CHANCES WILL ARRIVE
LATER MONDAY NIGHT AS A STRONG COLD FRONT IS FORCED THROUGH THE
FA...SUPPORTING INCREASING FGEN ACROSS MOST OF THE FA...ESP THE
SOUTHERN THIRD. DECENT LL MOISTURE COUPLED WITH MODEST FORCING WILL
AT LEAST SUPPORT UP TO A COUPLE INCHES OF SNOW ACROSS SCENTRAL
SD...WITH LESSER AMOUNTS OUTSIDE OF THE NORTHERN BLACK HILLS.
INCREASING FLOW WITH SUFFICIENT LL MOISTURE AND FORCING IN THE DGZ
WILL SUPPORT A GOOD PERIOD OF UPSLOPE IN THE NORTHERN HILLS WITH A
FEW INCHES POSSIBLE THERE BY TUE MORNING. STRONG CAA COUPLED WITH
FAST LL MOMENTUM WILL SUPPORT STRONG GUSTY WINDS NW WINDS ON THE SD
PLAINS EARLY TUES MORNING. ALTHOUGH SNOW AMOUNTS LOOK MINIMAL ON
THE PLAINS...BLOWING SNOW AND HAZARDOUS TRAVEL IS A CONCERN AND
WILL CERTAINLY NEED TO BE MONITORED WITH FUTURE FORECAST PACKAGES.
VERY COLD AIR WILL BEGIN TO ADVECT INTO THE REGION EARLY TUE MORNING
OVER THE NW HALF...WITH WINDCHILLS FALLING BELOW ZERO BY DAWN MOST
PLACES THERE.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 237 AM MST SUN MAR 1 2015

ARCTIC HIGH PRESSURE CONTINUES TO SURGE INTO THE NORTHERN PLAINS ON
TUESDAY...WITH STRONG NORTHWESTERLY WINDS PERSISTING THROUGH MUCH OF
THE DAY...AND TEMPERATURES STEADY OR CONTINUING TO FALL INTO THE
EVENING. LIGHT SNOW WILL BE LIKELY FROM NORTHEAST WYOMING THROUGH
SOUTHERN SOUTH DAKOTA...WITH SNOWFALL DIMINISHING FROM NORTH TO
SOUTH DURING THE DAY. TEMPERATURES WILL FALL BELOW ZERO ACROSS MUCH
OF THE AREA TUESDAY NIGHT.

THE BITTER COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP
IS EXPECTED. THIS NEXT WARM UP...HOWEVER...LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 237 AM MST SUN MAR 1 2015

LCL MVFR CIGS WILL BE POSSIBLE ACROSS NORTHEAST WYOMING AND THE
BLACK HILLS AREA THROUGH 18Z. OTHERWISE...VFR CONDITIONS ARE
EXPECTED THROUGH MONDAY MORNING.


&&

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

$$

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







000
FXUS63 KUNR 011544
AFDUNR

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

.UPDATE...
ISSUED AT 836 AM MST SUN MAR 1 2015

UPPER WAVE PASSING THROUGH EASTERN MT/WESTERN DAKOTAS IS PRODUCING
SOME SNOW SHOWERS ACROSS THE WYOMING BLACK HILLS AND AREAS
NORTHWEST OF THE CWA. HULETT IS REPORTING REDUCED
VISIBILITIES...SO ADDED SOME ISOLATED SNOW SHOWERS TO THE NORTHERN
HILLS. ALSO ADDED SOME SCATTERED FLURRIES ACROSS NORTHWEST SD
TODAY. UPDATED SKY GRIDS TO MATCH POPS/WX...BUT REST OF FORECAST
LOOKS ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 237 AM MST SUN MAR 1 2015

NW FLOW WILL PREVAIL IN THE PERIOD WITH A STRONG
PHASING SYSTEM ON TRACK MONDAY INTO TUES. A STRONG NW FLOW UPPER
LEVEL TROUGH WILL MERGE WITH THE EJECTING SW CONUS UPPER LEVEL
TROUGH...HELPING TO FORCE OF PERIOD OF LONG TRAJECTORY NORTHERLY
FLOW. THIS WILL SUPPORT ANOTHER ROUND OF ARCTIC AIR INTO THE
CONUS...ALONG WITH SOME SNOW AND WIND LOCALLY. A WEAKER SHORTWAVE
WILL TRAVERSE THE NORTHERN PLAINS TODAY...SUPPORTING REINFORCING
COLD THERMAL FIELDS. LACK OF MOISTURE WITH LARGE SCALE SINK
LOCALLY...EXPECTED TO SUPPORT DRY CONDS IN THE FA. INCREASING RETURN
FLOW FORCED BY SHORTWAVE RIDGING AHEAD OF THE APPROACHING STRONGER
NW FLOW IMPULSE...WILL SUPPORT A WARMER DAY MONDAY WITH CONTINUED
DRY CONDS...BEFORE SNOW AND WIND RETURN TO THE REGION MONDAY NIGHT.

TODAY...ANOTHER NW FLOW IMPULSE EXPECTED INTO THE REGION. ALTHOUGH
MOST IF NOT ALL OF THE LSA/UVM WILL PASS NORTH OF THE FA...CANNOT
RULE OUT A FEW HIGH BASED SNOW SHOWERS OVER THE NORTH HALF OF THE FA
AND OVER THE BLACK HILLS GIVEN FAIRLY STEEP LL LAPSE RATES.
HOWEVER...GIVEN DRY PROFILES...VIRGA WOULD BE ANTICIPATED THUS NO
POPS WARRANTED. STEEP LL LAPSE RATES PER INSOLATION AND MIXING WILL
FORCE FASTER FLOW DOWN SUPPORTING BREEZY CONDS...ESP ON THE SD
PLAINS WITH 15 TO 25 MPH WINDS EXPECTED. THERMAL FIELDS WILL
BASICALLY SEE NEAR NEUTRAL TEMP ADV...WITH TEMPS SIMILAR TO SAT/S
NUMBERS...SLIGHTLY WARMER. ASSOCIATED SFC HIGH WILL SHIFT SE OF THE
REGION TONIGHT...WITH GUSTY SOUTHERLY RETURN FLOW DEVELOPING OVER NE
WY AND PORTIONS OF THE SD PLAINS.

MONDAY...RETURN FLOW WILL REV UP WITH SOUTHERLY WINDS INCREASING
THROUGH THE DAY. WAA WILL BE ONGOING WITH MOST LOCATIONS SEEING 40S
FOR HIGHS...POSSIBLY NEAR 50 IN THE LEE OF THE BLACK HILLS. STRONG
NW FLOW UPPER TROUGH AND THE EJECTING SW CONUS UPPER LOW WILL
SUPPORT INCREASING LARGE SCALE ASCENT ACROSS THE SOUTHERN HALF OF
THE FA MONDAY EVENING WITH INCREASING MOISTURE AND FORCING
SUPPORTING INCREASING CHANCES FOR SNOW. BETTER CHANCES WILL ARRIVE
LATER MONDAY NIGHT AS A STRONG COLD FRONT IS FORCED THROUGH THE
FA...SUPPORTING INCREASING FGEN ACROSS MOST OF THE FA...ESP THE
SOUTHERN THIRD. DECENT LL MOISTURE COUPLED WITH MODEST FORCING WILL
AT LEAST SUPPORT UP TO A COUPLE INCHES OF SNOW ACROSS SCENTRAL
SD...WITH LESSER AMOUNTS OUTSIDE OF THE NORTHERN BLACK HILLS.
INCREASING FLOW WITH SUFFICIENT LL MOISTURE AND FORCING IN THE DGZ
WILL SUPPORT A GOOD PERIOD OF UPSLOPE IN THE NORTHERN HILLS WITH A
FEW INCHES POSSIBLE THERE BY TUE MORNING. STRONG CAA COUPLED WITH
FAST LL MOMENTUM WILL SUPPORT STRONG GUSTY WINDS NW WINDS ON THE SD
PLAINS EARLY TUES MORNING. ALTHOUGH SNOW AMOUNTS LOOK MINIMAL ON
THE PLAINS...BLOWING SNOW AND HAZARDOUS TRAVEL IS A CONCERN AND
WILL CERTAINLY NEED TO BE MONITORED WITH FUTURE FORECAST PACKAGES.
VERY COLD AIR WILL BEGIN TO ADVECT INTO THE REGION EARLY TUE MORNING
OVER THE NW HALF...WITH WINDCHILLS FALLING BELOW ZERO BY DAWN MOST
PLACES THERE.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 237 AM MST SUN MAR 1 2015

ARCTIC HIGH PRESSURE CONTINUES TO SURGE INTO THE NORTHERN PLAINS ON
TUESDAY...WITH STRONG NORTHWESTERLY WINDS PERSISTING THROUGH MUCH OF
THE DAY...AND TEMPERATURES STEADY OR CONTINUING TO FALL INTO THE
EVENING. LIGHT SNOW WILL BE LIKELY FROM NORTHEAST WYOMING THROUGH
SOUTHERN SOUTH DAKOTA...WITH SNOWFALL DIMINISHING FROM NORTH TO
SOUTH DURING THE DAY. TEMPERATURES WILL FALL BELOW ZERO ACROSS MUCH
OF THE AREA TUESDAY NIGHT.

THE BITTER COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP
IS EXPECTED. THIS NEXT WARM UP...HOWEVER...LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 237 AM MST SUN MAR 1 2015

LCL MVFR CIGS WILL BE POSSIBLE ACROSS NORTHEAST WYOMING AND THE
BLACK HILLS AREA THROUGH 18Z. OTHERWISE...VFR CONDITIONS ARE
EXPECTED THROUGH MONDAY MORNING.


&&

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

$$

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







000
FXUS63 KUNR 011544
AFDUNR

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

.UPDATE...
ISSUED AT 836 AM MST SUN MAR 1 2015

UPPER WAVE PASSING THROUGH EASTERN MT/WESTERN DAKOTAS IS PRODUCING
SOME SNOW SHOWERS ACROSS THE WYOMING BLACK HILLS AND AREAS
NORTHWEST OF THE CWA. HULETT IS REPORTING REDUCED
VISIBILITIES...SO ADDED SOME ISOLATED SNOW SHOWERS TO THE NORTHERN
HILLS. ALSO ADDED SOME SCATTERED FLURRIES ACROSS NORTHWEST SD
TODAY. UPDATED SKY GRIDS TO MATCH POPS/WX...BUT REST OF FORECAST
LOOKS ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 237 AM MST SUN MAR 1 2015

NW FLOW WILL PREVAIL IN THE PERIOD WITH A STRONG
PHASING SYSTEM ON TRACK MONDAY INTO TUES. A STRONG NW FLOW UPPER
LEVEL TROUGH WILL MERGE WITH THE EJECTING SW CONUS UPPER LEVEL
TROUGH...HELPING TO FORCE OF PERIOD OF LONG TRAJECTORY NORTHERLY
FLOW. THIS WILL SUPPORT ANOTHER ROUND OF ARCTIC AIR INTO THE
CONUS...ALONG WITH SOME SNOW AND WIND LOCALLY. A WEAKER SHORTWAVE
WILL TRAVERSE THE NORTHERN PLAINS TODAY...SUPPORTING REINFORCING
COLD THERMAL FIELDS. LACK OF MOISTURE WITH LARGE SCALE SINK
LOCALLY...EXPECTED TO SUPPORT DRY CONDS IN THE FA. INCREASING RETURN
FLOW FORCED BY SHORTWAVE RIDGING AHEAD OF THE APPROACHING STRONGER
NW FLOW IMPULSE...WILL SUPPORT A WARMER DAY MONDAY WITH CONTINUED
DRY CONDS...BEFORE SNOW AND WIND RETURN TO THE REGION MONDAY NIGHT.

TODAY...ANOTHER NW FLOW IMPULSE EXPECTED INTO THE REGION. ALTHOUGH
MOST IF NOT ALL OF THE LSA/UVM WILL PASS NORTH OF THE FA...CANNOT
RULE OUT A FEW HIGH BASED SNOW SHOWERS OVER THE NORTH HALF OF THE FA
AND OVER THE BLACK HILLS GIVEN FAIRLY STEEP LL LAPSE RATES.
HOWEVER...GIVEN DRY PROFILES...VIRGA WOULD BE ANTICIPATED THUS NO
POPS WARRANTED. STEEP LL LAPSE RATES PER INSOLATION AND MIXING WILL
FORCE FASTER FLOW DOWN SUPPORTING BREEZY CONDS...ESP ON THE SD
PLAINS WITH 15 TO 25 MPH WINDS EXPECTED. THERMAL FIELDS WILL
BASICALLY SEE NEAR NEUTRAL TEMP ADV...WITH TEMPS SIMILAR TO SAT/S
NUMBERS...SLIGHTLY WARMER. ASSOCIATED SFC HIGH WILL SHIFT SE OF THE
REGION TONIGHT...WITH GUSTY SOUTHERLY RETURN FLOW DEVELOPING OVER NE
WY AND PORTIONS OF THE SD PLAINS.

MONDAY...RETURN FLOW WILL REV UP WITH SOUTHERLY WINDS INCREASING
THROUGH THE DAY. WAA WILL BE ONGOING WITH MOST LOCATIONS SEEING 40S
FOR HIGHS...POSSIBLY NEAR 50 IN THE LEE OF THE BLACK HILLS. STRONG
NW FLOW UPPER TROUGH AND THE EJECTING SW CONUS UPPER LOW WILL
SUPPORT INCREASING LARGE SCALE ASCENT ACROSS THE SOUTHERN HALF OF
THE FA MONDAY EVENING WITH INCREASING MOISTURE AND FORCING
SUPPORTING INCREASING CHANCES FOR SNOW. BETTER CHANCES WILL ARRIVE
LATER MONDAY NIGHT AS A STRONG COLD FRONT IS FORCED THROUGH THE
FA...SUPPORTING INCREASING FGEN ACROSS MOST OF THE FA...ESP THE
SOUTHERN THIRD. DECENT LL MOISTURE COUPLED WITH MODEST FORCING WILL
AT LEAST SUPPORT UP TO A COUPLE INCHES OF SNOW ACROSS SCENTRAL
SD...WITH LESSER AMOUNTS OUTSIDE OF THE NORTHERN BLACK HILLS.
INCREASING FLOW WITH SUFFICIENT LL MOISTURE AND FORCING IN THE DGZ
WILL SUPPORT A GOOD PERIOD OF UPSLOPE IN THE NORTHERN HILLS WITH A
FEW INCHES POSSIBLE THERE BY TUE MORNING. STRONG CAA COUPLED WITH
FAST LL MOMENTUM WILL SUPPORT STRONG GUSTY WINDS NW WINDS ON THE SD
PLAINS EARLY TUES MORNING. ALTHOUGH SNOW AMOUNTS LOOK MINIMAL ON
THE PLAINS...BLOWING SNOW AND HAZARDOUS TRAVEL IS A CONCERN AND
WILL CERTAINLY NEED TO BE MONITORED WITH FUTURE FORECAST PACKAGES.
VERY COLD AIR WILL BEGIN TO ADVECT INTO THE REGION EARLY TUE MORNING
OVER THE NW HALF...WITH WINDCHILLS FALLING BELOW ZERO BY DAWN MOST
PLACES THERE.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 237 AM MST SUN MAR 1 2015

ARCTIC HIGH PRESSURE CONTINUES TO SURGE INTO THE NORTHERN PLAINS ON
TUESDAY...WITH STRONG NORTHWESTERLY WINDS PERSISTING THROUGH MUCH OF
THE DAY...AND TEMPERATURES STEADY OR CONTINUING TO FALL INTO THE
EVENING. LIGHT SNOW WILL BE LIKELY FROM NORTHEAST WYOMING THROUGH
SOUTHERN SOUTH DAKOTA...WITH SNOWFALL DIMINISHING FROM NORTH TO
SOUTH DURING THE DAY. TEMPERATURES WILL FALL BELOW ZERO ACROSS MUCH
OF THE AREA TUESDAY NIGHT.

THE BITTER COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP
IS EXPECTED. THIS NEXT WARM UP...HOWEVER...LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 237 AM MST SUN MAR 1 2015

LCL MVFR CIGS WILL BE POSSIBLE ACROSS NORTHEAST WYOMING AND THE
BLACK HILLS AREA THROUGH 18Z. OTHERWISE...VFR CONDITIONS ARE
EXPECTED THROUGH MONDAY MORNING.


&&

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

$$

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







000
FXUS63 KUNR 011544
AFDUNR

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

.UPDATE...
ISSUED AT 836 AM MST SUN MAR 1 2015

UPPER WAVE PASSING THROUGH EASTERN MT/WESTERN DAKOTAS IS PRODUCING
SOME SNOW SHOWERS ACROSS THE WYOMING BLACK HILLS AND AREAS
NORTHWEST OF THE CWA. HULETT IS REPORTING REDUCED
VISIBILITIES...SO ADDED SOME ISOLATED SNOW SHOWERS TO THE NORTHERN
HILLS. ALSO ADDED SOME SCATTERED FLURRIES ACROSS NORTHWEST SD
TODAY. UPDATED SKY GRIDS TO MATCH POPS/WX...BUT REST OF FORECAST
LOOKS ON TRACK FOR NOW.

&&

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 237 AM MST SUN MAR 1 2015

NW FLOW WILL PREVAIL IN THE PERIOD WITH A STRONG
PHASING SYSTEM ON TRACK MONDAY INTO TUES. A STRONG NW FLOW UPPER
LEVEL TROUGH WILL MERGE WITH THE EJECTING SW CONUS UPPER LEVEL
TROUGH...HELPING TO FORCE OF PERIOD OF LONG TRAJECTORY NORTHERLY
FLOW. THIS WILL SUPPORT ANOTHER ROUND OF ARCTIC AIR INTO THE
CONUS...ALONG WITH SOME SNOW AND WIND LOCALLY. A WEAKER SHORTWAVE
WILL TRAVERSE THE NORTHERN PLAINS TODAY...SUPPORTING REINFORCING
COLD THERMAL FIELDS. LACK OF MOISTURE WITH LARGE SCALE SINK
LOCALLY...EXPECTED TO SUPPORT DRY CONDS IN THE FA. INCREASING RETURN
FLOW FORCED BY SHORTWAVE RIDGING AHEAD OF THE APPROACHING STRONGER
NW FLOW IMPULSE...WILL SUPPORT A WARMER DAY MONDAY WITH CONTINUED
DRY CONDS...BEFORE SNOW AND WIND RETURN TO THE REGION MONDAY NIGHT.

TODAY...ANOTHER NW FLOW IMPULSE EXPECTED INTO THE REGION. ALTHOUGH
MOST IF NOT ALL OF THE LSA/UVM WILL PASS NORTH OF THE FA...CANNOT
RULE OUT A FEW HIGH BASED SNOW SHOWERS OVER THE NORTH HALF OF THE FA
AND OVER THE BLACK HILLS GIVEN FAIRLY STEEP LL LAPSE RATES.
HOWEVER...GIVEN DRY PROFILES...VIRGA WOULD BE ANTICIPATED THUS NO
POPS WARRANTED. STEEP LL LAPSE RATES PER INSOLATION AND MIXING WILL
FORCE FASTER FLOW DOWN SUPPORTING BREEZY CONDS...ESP ON THE SD
PLAINS WITH 15 TO 25 MPH WINDS EXPECTED. THERMAL FIELDS WILL
BASICALLY SEE NEAR NEUTRAL TEMP ADV...WITH TEMPS SIMILAR TO SAT/S
NUMBERS...SLIGHTLY WARMER. ASSOCIATED SFC HIGH WILL SHIFT SE OF THE
REGION TONIGHT...WITH GUSTY SOUTHERLY RETURN FLOW DEVELOPING OVER NE
WY AND PORTIONS OF THE SD PLAINS.

MONDAY...RETURN FLOW WILL REV UP WITH SOUTHERLY WINDS INCREASING
THROUGH THE DAY. WAA WILL BE ONGOING WITH MOST LOCATIONS SEEING 40S
FOR HIGHS...POSSIBLY NEAR 50 IN THE LEE OF THE BLACK HILLS. STRONG
NW FLOW UPPER TROUGH AND THE EJECTING SW CONUS UPPER LOW WILL
SUPPORT INCREASING LARGE SCALE ASCENT ACROSS THE SOUTHERN HALF OF
THE FA MONDAY EVENING WITH INCREASING MOISTURE AND FORCING
SUPPORTING INCREASING CHANCES FOR SNOW. BETTER CHANCES WILL ARRIVE
LATER MONDAY NIGHT AS A STRONG COLD FRONT IS FORCED THROUGH THE
FA...SUPPORTING INCREASING FGEN ACROSS MOST OF THE FA...ESP THE
SOUTHERN THIRD. DECENT LL MOISTURE COUPLED WITH MODEST FORCING WILL
AT LEAST SUPPORT UP TO A COUPLE INCHES OF SNOW ACROSS SCENTRAL
SD...WITH LESSER AMOUNTS OUTSIDE OF THE NORTHERN BLACK HILLS.
INCREASING FLOW WITH SUFFICIENT LL MOISTURE AND FORCING IN THE DGZ
WILL SUPPORT A GOOD PERIOD OF UPSLOPE IN THE NORTHERN HILLS WITH A
FEW INCHES POSSIBLE THERE BY TUE MORNING. STRONG CAA COUPLED WITH
FAST LL MOMENTUM WILL SUPPORT STRONG GUSTY WINDS NW WINDS ON THE SD
PLAINS EARLY TUES MORNING. ALTHOUGH SNOW AMOUNTS LOOK MINIMAL ON
THE PLAINS...BLOWING SNOW AND HAZARDOUS TRAVEL IS A CONCERN AND
WILL CERTAINLY NEED TO BE MONITORED WITH FUTURE FORECAST PACKAGES.
VERY COLD AIR WILL BEGIN TO ADVECT INTO THE REGION EARLY TUE MORNING
OVER THE NW HALF...WITH WINDCHILLS FALLING BELOW ZERO BY DAWN MOST
PLACES THERE.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 237 AM MST SUN MAR 1 2015

ARCTIC HIGH PRESSURE CONTINUES TO SURGE INTO THE NORTHERN PLAINS ON
TUESDAY...WITH STRONG NORTHWESTERLY WINDS PERSISTING THROUGH MUCH OF
THE DAY...AND TEMPERATURES STEADY OR CONTINUING TO FALL INTO THE
EVENING. LIGHT SNOW WILL BE LIKELY FROM NORTHEAST WYOMING THROUGH
SOUTHERN SOUTH DAKOTA...WITH SNOWFALL DIMINISHING FROM NORTH TO
SOUTH DURING THE DAY. TEMPERATURES WILL FALL BELOW ZERO ACROSS MUCH
OF THE AREA TUESDAY NIGHT.

THE BITTER COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP
IS EXPECTED. THIS NEXT WARM UP...HOWEVER...LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 237 AM MST SUN MAR 1 2015

LCL MVFR CIGS WILL BE POSSIBLE ACROSS NORTHEAST WYOMING AND THE
BLACK HILLS AREA THROUGH 18Z. OTHERWISE...VFR CONDITIONS ARE
EXPECTED THROUGH MONDAY MORNING.


&&

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

$$

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








000
FXUS65 KCYS 011225 CCA
AFDCYS

AREA FORECAST DISCUSSION...AMENDED AVIATION SECTION.
NATIONAL WEATHER SERVICE CHEYENNE WY
524 AM MST SUN MAR 1 2015

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 400 AM MST SUN MAR 1 2015

LATEST GOES WATER VAPOR IMAGERY SHOWED THE SPLIT CLOSED UPPER LOW
SLOWLY SINKING SOUTHEAST ALONG THE CENTRAL CA COAST. THE BASE OF
THE NORTHERN STREAM TROUGH WAS MOVING EAST ACROSS THE DAKOTAS. A
DEFORMATION ZONE STRETCHED NORTHEAST TO SOUTHWEST FROM WESTERN NE
ACROSS NORTHERN CO. NARROW BAND OF UPPER LIFT COMBINED WITH MOISTURE
AND WEAK UPSLOPE RESULTED IN AN AREA OF LIGHT SNOW OVER PORTIONS
OF SOUTHEAST WY AND WESTERN NE. HRRR MODEL PROGS THIS AREA TO WEAKEN
AS IT MOVES FURTHER EAST THROUGH DAYBREAK. TEMPERATURES WERE IN THE
SINGLE DIGITS AND TEENS WITH LIGHT WINDS.

FORECAST CONCERNS DURING THE SHORT TERM WILL FOCUS ON THE DEVELOPING
WINTER STORM AND ITS IMPACTS ON OUR AREA...PARTICULARLY FROM LATE
TONIGHT THROUGH TUESDAY. CLOSED UPPER LOW NEAR SOUTHERN CA COAST
GRADUALLY OPENS UP AND EJECTS NORTHEAST AS ANOTHER SHORTWAVE DROPS
SOUTH ALONG THE CA COAST DURING THE NEXT 24 TO 48 HOURS. THE MODEL
CONSENSUS PROGS A LOW PRESSURE SYSTEM TO FORM NEAR THE FOUR CORNERS
REGION AND TRACK NORTHEAST ACROSS COLORADO. LIGHT SNOW REDEVELOPS
LATER TODAY OVER THE SOUTHERN MOUNTAINS AND BECOMES MORE WIDESPREAD
AND HEAVIER LATE TONIGHT INTO MONDAY. THE GFS IS SLIGHTLY DEEPER
AND FASTER THAN THE ECMWF WITH REGARDS TO THE SURFACE LOW AND ITS
MOTION. THEY ARE SIMILAR WITH THE EASTWARD TRACK OF THE LOW INTO
THE CENTRAL PLAINS EARLY TUESDAY MORNING. THEY ALSO AGREE WITH THE
ARCTIC COLD FRONTAL PASSAGE DURING THIS TIME PERIOD. WINDS SHIFT
TO NORTHERLY AND BECOME GUSTY TUESDAY. SNOW WILL BE WIDESPREAD
OVER THE CWA MONDAY NIGHT AND TUESDAY. THE COMBINATION OF FALLING
AND BLOWING SNOW WILL RESULT IN HAZARDOUS TRAVEL WEST OF THE
LARAMIE RANGE...ESPECIALLY MONDAY THROUGH TUESDAY. LATEST WPC
GUIDANCE PROGS 1-2 FT OF SNOW FOR THE SNOWY/SIERRA MADRE RANGES
WITH UP TO A FOOT FOR THE NEARBY VALLEYS. ISSUED A WINTER STORM
WATCH FOR WY ZONES 111-114 LATE TONIGHT THROUGH LATE TUESDAY NIGHT
FOR THE POTENTIAL OF HEAVY SNOW. FURTHER NORTH AND EAST...WE`RE
LOOKING AT ADVISORY ACCUMULATIONS...GENERALLY 4-8 INCHES. THE
SOUTHERN LARAMIE RANGE COULD GET CLOSE TO A FOOT AS WELL. THE NEXT
SHIFT MAY UPGRADE AND/OR EXTEND THE WINTER HEADLINES AFTER LOOKING
AT THE 12Z/18Z MODEL GUIDANCE.

HIGHS TODAY WILL BE SIMILAR TO SATURDAY WITH MOSTLY UPPER TEENS TO
UPPER 20S. LOWS TONIGHT AND MONDAY NIGHT WILL AVERAGE IN THE TEENS.
MONDAY WILL BE MILDER WITH SOUTHWESTERLY WINDS. EXPECT HIGHS IN THE
30S TO AROUND 40. TEMPERATURES TUESDAY WILL NOT RISE MUCH FROM THE
EARLY MORNING LOWS...AND WILL BE FALLING THROUGH THE DAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM MST SUN MAR 1 2015

THE MAIN CHALLENGE IN THE EXTENDED WILL BE TEMPERATURE TRENDS AS WE
STILL ANTICIPATE A BAND OF NEW SNOWPACK SOMEWHERE IN THE CWA. GFS/EC
BOTH SHOW A SECONDARY SHORTWAVE DIVING ACROSS WY BETWEEN 00Z AND 12Z
WED. MODEST PVA SHOULD BE ENOUGH FOR SNOW SHOWERS TO LINGER INTO WED
MORNING OR PERHAPS EARLY AFTERNOON. MEDIUM RANGE 700-300 MILLIBAR RH
PROGS SUGGEST A DRYING COLUMN BY THIS TIME...SO EXPECT LESS THAN AN
INCH OF ADDITIONAL ACCUMULATION OVER THE LOWER ELEVATIONS AFTER 00Z
WED. TEMPERATURES WILL BE TRICKY ON TUE NIGHT AS CLOUDS WILL PREVENT
SIGNIFICANT RADIATIONAL COOLING. HOWEVER...MODELS AGREE WITH STRONG
LOW LEVEL COLD ADVECTION PUSHING H7 TEMPS AS LOW AS -20 DEG C BY 12Z
WED PER THE EURO. GIVEN AN AIR MASS THIS COLD...CONFIDENCE IS FAIRLY
HIGH THAT MANY AREAS WILL BE BELOW ZERO FOR LOWS. DID NOT STRAY TOO
FAR AWAY FROM GUIDANCE THOUGH. COOLEST TEMPERATURES ON WED SHOULD BE
FOUND OVER THE MOST SUBSTANTIAL SNOWPACK. GUIDANCE SUGGESTS THE BEST
CHANCE FOR LOW-ELEVATION SIGNIFICANT SNOWFALL EARLY IN THE WEEK WILL
BE WEST OF THE LARAMIE RANGE...SO UNDERCUT MOS BY SEVERAL DEGREES IN
THOSE AREAS. KEPT HIGHS BELOW GUIDANCE ACROSS THE BOARD WITH MUCH OF
THE AREA LIKELY TO RECEIVE ACCUMULATING SNOW IN THE SHORT TERM.

IMPROVING TEMPERATURES LATER IN THE WEEK AS UPPER-LEVEL RIDGING AND
LOW LEVEL DOWNSLOPE RETURN TO THE REGION. A BACK DOOR COLD FRONT IS
PROGGED TO SINK SOUTHWARD ON FRI AFTERNOON...POSSIBLY HAVING A SMALL
IMPACT ON HIGHS WITH COLD ADVECTION ALOFT. CANNOT RULE OUT ISOLATED
RAIN OR SNOW SHOWERS ON FRI NIGHT OR SAT MORNING WITH THE ARRIVAL OF
BETTER MID LEVEL SUPPORT. HOWEVER...KEPT THE FORECAST DRY FOR NOW AS
THIS SYSTEM LOOKS TO BE A BIT MOISTURE STARVED. STILL EXPECT A WINDY
PERIOD FROM WED NIGHT THROUGH FRI OVER THE WIND PRONE AREAS. THE GFS
HAS BEEN CONSISTENT WITH A STRONG H85 CAG-CPR GRADIENT IN EXCESS OF
60 METERS AND 45 TO 50 KT FLOW OVER ARL AND BRX AT H75 THROUGH MUCH
OF THAT TIME PERIOD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 515 AM MST SUN MAR 1 2015

SNOW SHOWERS WILL CONTINUE TO DIMINISH THIS MORNING WITH GENERALLY
VFR CONDITIONS PREVAILING. SPORADIC MVFR CIGS ARE POSSIBLE THROUGH
THE MORNING BENEATH A STRATUS DECK AROUND 5K FEET AGL. A COLD FRONT
WILL SWEEP ACROSS THE AREA TONIGHT...BRINGING ANOTHER ROUND OF SNOW
TO AREAS ALONG AND SOUTH OF I80. MVFR TO IFR CIGS/VSBYS ARE LIKELY
AFTER 06Z MON. WINDS WILL GENERALLY BE LIGHT THROUGH THE TAF PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 321 AM MST SUN MAR 1 2015

A WEAK UPPER LEVEL DISTURBANCE WILL PRODUCE LIGHT SNOW EARLY THIS
MORNING OVER FAR SOUTHEAST WYOMING AND SOUTHERN NEBRASKA PANHANDLE.
A LOW PRESSURE SYSTEM AND ASSOCIATED UPPER LEVEL TROUGH WILL APPROACH
FROM THE SOUTHWEST TONIGHT AND MONDAY...AND MOVE ACROSS THE CENTRAL
ROCKIES MONDAY NIGHT AND TUESDAY. SNOW WILL DEVELOP TONIGHT ACROSS
SOUTH CENTRAL WYOMING AND BECOME MORE WIDESPREAD MONDAY AND MONDAY
NIGHT. THE SNOW WILL BE HEAVY AT TIMES...ESPECIALLY OVER THE HIGHER
TERRAIN. THE SNOW WILL TAPER OFF TUESDAY NIGHT. A ARCTIC COLD FRONT
WILL PLUNGE SOUTH THROUGH THE DISTRICT MONDAY NIGHT. BITTERLY COLD
TEMPERATURES AND WIND CHILLS WILL PREVAIL TUESDAY THROUGH WEDNESDAY
BEFORE GRADUALLY MODERATING TEMPERATURES LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE TUESDAY NIGHT
     FOR WYZ111>114.

NE...NONE.
&&

$$

SHORT TERM...MAJ
LONG TERM...CLH
AVIATION...CLH
FIRE WEATHER...MAJ




000
FXUS65 KCYS 011225 CCA
AFDCYS

AREA FORECAST DISCUSSION...AMENDED AVIATION SECTION.
NATIONAL WEATHER SERVICE CHEYENNE WY
524 AM MST SUN MAR 1 2015

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 400 AM MST SUN MAR 1 2015

LATEST GOES WATER VAPOR IMAGERY SHOWED THE SPLIT CLOSED UPPER LOW
SLOWLY SINKING SOUTHEAST ALONG THE CENTRAL CA COAST. THE BASE OF
THE NORTHERN STREAM TROUGH WAS MOVING EAST ACROSS THE DAKOTAS. A
DEFORMATION ZONE STRETCHED NORTHEAST TO SOUTHWEST FROM WESTERN NE
ACROSS NORTHERN CO. NARROW BAND OF UPPER LIFT COMBINED WITH MOISTURE
AND WEAK UPSLOPE RESULTED IN AN AREA OF LIGHT SNOW OVER PORTIONS
OF SOUTHEAST WY AND WESTERN NE. HRRR MODEL PROGS THIS AREA TO WEAKEN
AS IT MOVES FURTHER EAST THROUGH DAYBREAK. TEMPERATURES WERE IN THE
SINGLE DIGITS AND TEENS WITH LIGHT WINDS.

FORECAST CONCERNS DURING THE SHORT TERM WILL FOCUS ON THE DEVELOPING
WINTER STORM AND ITS IMPACTS ON OUR AREA...PARTICULARLY FROM LATE
TONIGHT THROUGH TUESDAY. CLOSED UPPER LOW NEAR SOUTHERN CA COAST
GRADUALLY OPENS UP AND EJECTS NORTHEAST AS ANOTHER SHORTWAVE DROPS
SOUTH ALONG THE CA COAST DURING THE NEXT 24 TO 48 HOURS. THE MODEL
CONSENSUS PROGS A LOW PRESSURE SYSTEM TO FORM NEAR THE FOUR CORNERS
REGION AND TRACK NORTHEAST ACROSS COLORADO. LIGHT SNOW REDEVELOPS
LATER TODAY OVER THE SOUTHERN MOUNTAINS AND BECOMES MORE WIDESPREAD
AND HEAVIER LATE TONIGHT INTO MONDAY. THE GFS IS SLIGHTLY DEEPER
AND FASTER THAN THE ECMWF WITH REGARDS TO THE SURFACE LOW AND ITS
MOTION. THEY ARE SIMILAR WITH THE EASTWARD TRACK OF THE LOW INTO
THE CENTRAL PLAINS EARLY TUESDAY MORNING. THEY ALSO AGREE WITH THE
ARCTIC COLD FRONTAL PASSAGE DURING THIS TIME PERIOD. WINDS SHIFT
TO NORTHERLY AND BECOME GUSTY TUESDAY. SNOW WILL BE WIDESPREAD
OVER THE CWA MONDAY NIGHT AND TUESDAY. THE COMBINATION OF FALLING
AND BLOWING SNOW WILL RESULT IN HAZARDOUS TRAVEL WEST OF THE
LARAMIE RANGE...ESPECIALLY MONDAY THROUGH TUESDAY. LATEST WPC
GUIDANCE PROGS 1-2 FT OF SNOW FOR THE SNOWY/SIERRA MADRE RANGES
WITH UP TO A FOOT FOR THE NEARBY VALLEYS. ISSUED A WINTER STORM
WATCH FOR WY ZONES 111-114 LATE TONIGHT THROUGH LATE TUESDAY NIGHT
FOR THE POTENTIAL OF HEAVY SNOW. FURTHER NORTH AND EAST...WE`RE
LOOKING AT ADVISORY ACCUMULATIONS...GENERALLY 4-8 INCHES. THE
SOUTHERN LARAMIE RANGE COULD GET CLOSE TO A FOOT AS WELL. THE NEXT
SHIFT MAY UPGRADE AND/OR EXTEND THE WINTER HEADLINES AFTER LOOKING
AT THE 12Z/18Z MODEL GUIDANCE.

HIGHS TODAY WILL BE SIMILAR TO SATURDAY WITH MOSTLY UPPER TEENS TO
UPPER 20S. LOWS TONIGHT AND MONDAY NIGHT WILL AVERAGE IN THE TEENS.
MONDAY WILL BE MILDER WITH SOUTHWESTERLY WINDS. EXPECT HIGHS IN THE
30S TO AROUND 40. TEMPERATURES TUESDAY WILL NOT RISE MUCH FROM THE
EARLY MORNING LOWS...AND WILL BE FALLING THROUGH THE DAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM MST SUN MAR 1 2015

THE MAIN CHALLENGE IN THE EXTENDED WILL BE TEMPERATURE TRENDS AS WE
STILL ANTICIPATE A BAND OF NEW SNOWPACK SOMEWHERE IN THE CWA. GFS/EC
BOTH SHOW A SECONDARY SHORTWAVE DIVING ACROSS WY BETWEEN 00Z AND 12Z
WED. MODEST PVA SHOULD BE ENOUGH FOR SNOW SHOWERS TO LINGER INTO WED
MORNING OR PERHAPS EARLY AFTERNOON. MEDIUM RANGE 700-300 MILLIBAR RH
PROGS SUGGEST A DRYING COLUMN BY THIS TIME...SO EXPECT LESS THAN AN
INCH OF ADDITIONAL ACCUMULATION OVER THE LOWER ELEVATIONS AFTER 00Z
WED. TEMPERATURES WILL BE TRICKY ON TUE NIGHT AS CLOUDS WILL PREVENT
SIGNIFICANT RADIATIONAL COOLING. HOWEVER...MODELS AGREE WITH STRONG
LOW LEVEL COLD ADVECTION PUSHING H7 TEMPS AS LOW AS -20 DEG C BY 12Z
WED PER THE EURO. GIVEN AN AIR MASS THIS COLD...CONFIDENCE IS FAIRLY
HIGH THAT MANY AREAS WILL BE BELOW ZERO FOR LOWS. DID NOT STRAY TOO
FAR AWAY FROM GUIDANCE THOUGH. COOLEST TEMPERATURES ON WED SHOULD BE
FOUND OVER THE MOST SUBSTANTIAL SNOWPACK. GUIDANCE SUGGESTS THE BEST
CHANCE FOR LOW-ELEVATION SIGNIFICANT SNOWFALL EARLY IN THE WEEK WILL
BE WEST OF THE LARAMIE RANGE...SO UNDERCUT MOS BY SEVERAL DEGREES IN
THOSE AREAS. KEPT HIGHS BELOW GUIDANCE ACROSS THE BOARD WITH MUCH OF
THE AREA LIKELY TO RECEIVE ACCUMULATING SNOW IN THE SHORT TERM.

IMPROVING TEMPERATURES LATER IN THE WEEK AS UPPER-LEVEL RIDGING AND
LOW LEVEL DOWNSLOPE RETURN TO THE REGION. A BACK DOOR COLD FRONT IS
PROGGED TO SINK SOUTHWARD ON FRI AFTERNOON...POSSIBLY HAVING A SMALL
IMPACT ON HIGHS WITH COLD ADVECTION ALOFT. CANNOT RULE OUT ISOLATED
RAIN OR SNOW SHOWERS ON FRI NIGHT OR SAT MORNING WITH THE ARRIVAL OF
BETTER MID LEVEL SUPPORT. HOWEVER...KEPT THE FORECAST DRY FOR NOW AS
THIS SYSTEM LOOKS TO BE A BIT MOISTURE STARVED. STILL EXPECT A WINDY
PERIOD FROM WED NIGHT THROUGH FRI OVER THE WIND PRONE AREAS. THE GFS
HAS BEEN CONSISTENT WITH A STRONG H85 CAG-CPR GRADIENT IN EXCESS OF
60 METERS AND 45 TO 50 KT FLOW OVER ARL AND BRX AT H75 THROUGH MUCH
OF THAT TIME PERIOD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 515 AM MST SUN MAR 1 2015

SNOW SHOWERS WILL CONTINUE TO DIMINISH THIS MORNING WITH GENERALLY
VFR CONDITIONS PREVAILING. SPORADIC MVFR CIGS ARE POSSIBLE THROUGH
THE MORNING BENEATH A STRATUS DECK AROUND 5K FEET AGL. A COLD FRONT
WILL SWEEP ACROSS THE AREA TONIGHT...BRINGING ANOTHER ROUND OF SNOW
TO AREAS ALONG AND SOUTH OF I80. MVFR TO IFR CIGS/VSBYS ARE LIKELY
AFTER 06Z MON. WINDS WILL GENERALLY BE LIGHT THROUGH THE TAF PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 321 AM MST SUN MAR 1 2015

A WEAK UPPER LEVEL DISTURBANCE WILL PRODUCE LIGHT SNOW EARLY THIS
MORNING OVER FAR SOUTHEAST WYOMING AND SOUTHERN NEBRASKA PANHANDLE.
A LOW PRESSURE SYSTEM AND ASSOCIATED UPPER LEVEL TROUGH WILL APPROACH
FROM THE SOUTHWEST TONIGHT AND MONDAY...AND MOVE ACROSS THE CENTRAL
ROCKIES MONDAY NIGHT AND TUESDAY. SNOW WILL DEVELOP TONIGHT ACROSS
SOUTH CENTRAL WYOMING AND BECOME MORE WIDESPREAD MONDAY AND MONDAY
NIGHT. THE SNOW WILL BE HEAVY AT TIMES...ESPECIALLY OVER THE HIGHER
TERRAIN. THE SNOW WILL TAPER OFF TUESDAY NIGHT. A ARCTIC COLD FRONT
WILL PLUNGE SOUTH THROUGH THE DISTRICT MONDAY NIGHT. BITTERLY COLD
TEMPERATURES AND WIND CHILLS WILL PREVAIL TUESDAY THROUGH WEDNESDAY
BEFORE GRADUALLY MODERATING TEMPERATURES LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE TUESDAY NIGHT
     FOR WYZ111>114.

NE...NONE.
&&

$$

SHORT TERM...MAJ
LONG TERM...CLH
AVIATION...CLH
FIRE WEATHER...MAJ



000
FXUS65 KCYS 011130
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
430 AM MST SUN MAR 1 2015

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 400 AM MST SUN MAR 1 2015

LATEST GOES WATER VAPOR IMAGERY SHOWED THE SPLIT CLOSED UPPER LOW
SLOWLY SINKING SOUTHEAST ALONG THE CENTRAL CA COAST. THE BASE OF
THE NORTHERN STREAM TROUGH WAS MOVING EAST ACROSS THE DAKOTAS. A
DEFORMATION ZONE STRETCHED NORTHEAST TO SOUTHWEST FROM WESTERN NE
ACROSS NORTHERN CO. NARROW BAND OF UPPER LIFT COMBINED WITH MOISTURE
AND WEAK UPSLOPE RESULTED IN AN AREA OF LIGHT SNOW OVER PORTIONS
OF SOUTHEAST WY AND WESTERN NE. HRRR MODEL PROGS THIS AREA TO WEAKEN
AS IT MOVES FURTHER EAST THROUGH DAYBREAK. TEMPERATURES WERE IN THE
SINGLE DIGITS AND TEENS WITH LIGHT WINDS.

FORECAST CONCERNS DURING THE SHORT TERM WILL FOCUS ON THE DEVELOPING
WINTER STORM AND ITS IMPACTS ON OUR AREA...PARTICULARLY FROM LATE
TONIGHT THROUGH TUESDAY. CLOSED UPPER LOW NEAR SOUTHERN CA COAST
GRADUALLY OPENS UP AND EJECTS NORTHEAST AS ANOTHER SHORTWAVE DROPS
SOUTH ALONG THE CA COAST DURING THE NEXT 24 TO 48 HOURS. THE MODEL
CONSENSUS PROGS A LOW PRESSURE SYSTEM TO FORM NEAR THE FOUR CORNERS
REGION AND TRACK NORTHEAST ACROSS COLORADO. LIGHT SNOW REDEVELOPS
LATER TODAY OVER THE SOUTHERN MOUNTAINS AND BECOMES MORE WIDESPREAD
AND HEAVIER LATE TONIGHT INTO MONDAY. THE GFS IS SLIGHTLY DEEPER
AND FASTER THAN THE ECMWF WITH REGARDS TO THE SURFACE LOW AND ITS
MOTION. THEY ARE SIMILAR WITH THE EASTWARD TRACK OF THE LOW INTO
THE CENTRAL PLAINS EARLY TUESDAY MORNING. THEY ALSO AGREE WITH THE
ARCTIC COLD FRONTAL PASSAGE DURING THIS TIME PERIOD. WINDS SHIFT
TO NORTHERLY AND BECOME GUSTY TUESDAY. SNOW WILL BE WIDESPREAD
OVER THE CWA MONDAY NIGHT AND TUESDAY. THE COMBINATION OF FALLING
AND BLOWING SNOW WILL RESULT IN HAZARDOUS TRAVEL WEST OF THE
LARAMIE RANGE...ESPECIALLY MONDAY THROUGH TUESDAY. LATEST WPC
GUIDANCE PROGS 1-2 FT OF SNOW FOR THE SNOWY/SIERRA MADRE RANGES
WITH UP TO A FOOT FOR THE NEARBY VALLEYS. ISSUED A WINTER STORM
WATCH FOR WY ZONES 111-114 LATE TONIGHT THROUGH LATE TUESDAY NIGHT
FOR THE POTENTIAL OF HEAVY SNOW. FURTHER NORTH AND EAST...WE`RE
LOOKING AT ADVISORY ACCUMULATIONS...GENERALLY 4-8 INCHES. THE
SOUTHERN LARAMIE RANGE COULD GET CLOSE TO A FOOT AS WELL. THE NEXT
SHIFT MAY UPGRADE AND/OR EXTEND THE WINTER HEADLINES AFTER LOOKING
AT THE 12Z/18Z MODEL GUIDANCE.

HIGHS TODAY WILL BE SIMILAR TO SATURDAY WITH MOSTLY UPPER TEENS TO
UPPER 20S. LOWS TONIGHT AND MONDAY NIGHT WILL AVERAGE IN THE TEENS.
MONDAY WILL BE MILDER WITH SOUTHWESTERLY WINDS. EXPECT HIGHS IN THE
30S TO AROUND 40. TEMPERATURES TUESDAY WILL NOT RISE MUCH FROM THE
EARLY MORNING LOWS...AND WILL BE FALLING THROUGH THE DAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM MST SUN MAR 1 2015

THE MAIN CHALLENGE IN THE EXTENDED WILL BE TEMPERATURE TRENDS AS WE
STILL ANTICIPATE A BAND OF NEW SNOWPACK SOMEWHERE IN THE CWA. GFS/EC
BOTH SHOW A SECONDARY SHORTWAVE DIVING ACROSS WY BETWEEN 00Z AND 12Z
WED. MODEST PVA SHOULD BE ENOUGH FOR SNOW SHOWERS TO LINGER INTO WED
MORNING OR PERHAPS EARLY AFTERNOON. MEDIUM RANGE 700-300 MILLIBAR RH
PROGS SUGGEST A DRYING COLUMN BY THIS TIME...SO EXPECT LESS THAN AN
INCH OF ADDITIONAL ACCUMULATION OVER THE LOWER ELEVATIONS AFTER 00Z
WED. TEMPERATURES WILL BE TRICKY ON TUE NIGHT AS CLOUDS WILL PREVENT
SIGNIFICANT RADIATIONAL COOLING. HOWEVER...MODELS AGREE WITH STRONG
LOW LEVEL COLD ADVECTION PUSHING H7 TEMPS AS LOW AS -20 DEG C BY 12Z
WED PER THE EURO. GIVEN AN AIR MASS THIS COLD...CONFIDENCE IS FAIRLY
HIGH THAT MANY AREAS WILL BE BELOW ZERO FOR LOWS. DID NOT STRAY TOO
FAR AWAY FROM GUIDANCE THOUGH. COOLEST TEMPERATURES ON WED SHOULD BE
FOUND OVER THE MOST SUBSTANTIAL SNOWPACK. GUIDANCE SUGGESTS THE BEST
CHANCE FOR LOW-ELEVATION SIGNIFICANT SNOWFALL EARLY IN THE WEEK WILL
BE WEST OF THE LARAMIE RANGE...SO UNDERCUT MOS BY SEVERAL DEGREES IN
THOSE AREAS. KEPT HIGHS BELOW GUIDANCE ACROSS THE BOARD WITH MUCH OF
THE AREA LIKELY TO RECEIVE ACCUMULATING SNOW IN THE SHORT TERM.

IMPROVING TEMPERATURES LATER IN THE WEEK AS UPPER-LEVEL RIDGING AND
LOW LEVEL DOWNSLOPE RETURN TO THE REGION. A BACK DOOR COLD FRONT IS
PROGGED TO SINK SOUTHWARD ON FRI AFTERNOON...POSSIBLY HAVING A SMALL
IMPACT ON HIGHS WITH COLD ADVECTION ALOFT. CANNOT RULE OUT ISOLATED
RAIN OR SNOW SHOWERS ON FRI NIGHT OR SAT MORNING WITH THE ARRIVAL OF
BETTER MID LEVEL SUPPORT. HOWEVER...KEPT THE FORECAST DRY FOR NOW AS
THIS SYSTEM LOOKS TO BE A BIT MOISTURE STARVED. STILL EXPECT A WINDY
PERIOD FROM WED NIGHT THROUGH FRI OVER THE WIND PRONE AREAS. THE GFS
HAS BEEN CONSISTENT WITH A STRONG H85 CAG-CPR GRADIENT IN EXCESS OF
60 METERS AND 45 TO 50 KT FLOW OVER ARL AND BRX AT H75 THROUGH MUCH
OF THAT TIME PERIOD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 425 AM MST SUN MAR 1 2015

SNOW SHOWERS WILL CONTINUE TO DIMINISH THIS MORNING WITH VFR
CONDITIONS PREVAILING. A COLD FRONT WILL SWEEP ACROSS THE AREA
THIS EVENING AND OVERNIGHT...BRINGING ANOTHER ROUND OF SNOW TO
AREAS ALONG AND SOUTH OF INTERSTATE 80. MVFR TO IFR CIGS/VSBYS
ARE LIKELY AFTER 06Z MON. WINDS WILL GENERALLY BE LIGHT THROUGH
THE TAF PERIOD.

&&

.FIRE WEATHER...
ISSUED AT 321 AM MST SUN MAR 1 2015

A WEAK UPPER LEVEL DISTURBANCE WILL PRODUCE LIGHT SNOW EARLY THIS
MORNING OVER FAR SOUTHEAST WYOMING AND SOUTHERN NEBRASKA PANHANDLE.
A LOW PRESSURE SYSTEM AND ASSOCIATED UPPER LEVEL TROUGH WILL APPROACH
FROM THE SOUTHWEST TONIGHT AND MONDAY...AND MOVE ACROSS THE CENTRAL
ROCKIES MONDAY NIGHT AND TUESDAY. SNOW WILL DEVELOP TONIGHT ACROSS
SOUTH CENTRAL WYOMING AND BECOME MORE WIDESPREAD MONDAY AND MONDAY
NIGHT. THE SNOW WILL BE HEAVY AT TIMES...ESPECIALLY OVER THE HIGHER
TERRAIN. THE SNOW WILL TAPER OFF TUESDAY NIGHT. A ARCTIC COLD FRONT
WILL PLUNGE SOUTH THROUGH THE DISTRICT MONDAY NIGHT. BITTERLY COLD
TEMPERATURES AND WIND CHILLS WILL PREVAIL TUESDAY THROUGH WEDNESDAY
BEFORE GRADUALLY MODERATING TEMPERATURES LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE TUESDAY NIGHT
     FOR WYZ111>114.

NE...NONE.
&&

$$

SHORT TERM...MAJ
LONG TERM...CLH
AVIATION...CLH
FIRE WEATHER...MAJ




000
FXUS65 KCYS 011106
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
406 AM MST SUN MAR 1 2015

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 400 AM MST SUN MAR 1 2015

LATEST GOES WATER VAPOR IMAGERY SHOWED THE SPLIT CLOSED UPPER LOW
SLOWLY SINKING SOUTHEAST ALONG THE CENTRAL CA COAST. THE BASE OF
THE NORTHERN STREAM TROUGH WAS MOVING EAST ACROSS THE DAKOTAS. A
DEFORMATION ZONE STRETCHED NORTHEAST TO SOUTHWEST FROM WESTERN NE
ACROSS NORTHERN CO. NARROW BAND OF UPPER LIFT COMBINED WITH MOISTURE
AND WEAK UPSLOPE RESULTED IN AN AREA OF LIGHT SNOW OVER PORTIONS
OF SOUTHEAST WY AND WESTERN NE. HRRR MODEL PROGS THIS AREA TO WEAKEN
AS IT MOVES FURTHER EAST THROUGH DAYBREAK. TEMPERATURES WERE IN THE
SINGLE DIGITS AND TEENS WITH LIGHT WINDS.

FORECAST CONCERNS DURING THE SHORT TERM WILL FOCUS ON THE DEVELOPING
WINTER STORM AND ITS IMPACTS ON OUR AREA...PARTICULARLY FROM LATE
TONIGHT THROUGH TUESDAY. CLOSED UPPER LOW NEAR SOUTHERN CA COAST
GRADUALLY OPENS UP AND EJECTS NORTHEAST AS ANOTHER SHORTWAVE DROPS
SOUTH ALONG THE CA COAST DURING THE NEXT 24 TO 48 HOURS. THE MODEL
CONSENSUS PROGS A LOW PRESSURE SYSTEM TO FORM NEAR THE FOUR CORNERS
REGION AND TRACK NORTHEAST ACROSS COLORADO. LIGHT SNOW REDEVELOPS
LATER TODAY OVER THE SOUTHERN MOUNTAINS AND BECOMES MORE WIDESPREAD
AND HEAVIER LATE TONIGHT INTO MONDAY. THE GFS IS SLIGHTLY DEEPER
AND FASTER THAN THE ECMWF WITH REGARDS TO THE SURFACE LOW AND ITS
MOTION. THEY ARE SIMILAR WITH THE EASTWARD TRACK OF THE LOW INTO
THE CENTRAL PLAINS EARLY TUESDAY MORNING. THEY ALSO AGREE WITH THE
ARCTIC COLD FRONTAL PASSAGE DURING THIS TIME PERIOD. WINDS SHIFT
TO NORTHERLY AND BECOME GUSTY TUESDAY. SNOW WILL BE WIDESPREAD
OVER THE CWA MONDAY NIGHT AND TUESDAY. THE COMBINATION OF FALLING
AND BLOWING SNOW WILL RESULT IN HAZARDOUS TRAVEL WEST OF THE
LARAMIE RANGE...ESPECIALLY MONDAY THROUGH TUESDAY. LATEST WPC
GUIDANCE PROGS 1-2 FT OF SNOW FOR THE SNOWY/SIERRA MADRE RANGES
WITH UP TO A FOOT FOR THE NEARBY VALLEYS. ISSUED A WINTER STORM
WATCH FOR WY ZONES 111-114 LATE TONIGHT THROUGH LATE TUESDAY NIGHT
FOR THE POTENTIAL OF HEAVY SNOW. FURTHER NORTH AND EAST...WE`RE
LOOKING AT ADVISORY ACCUMULATIONS...GENERALLY 4-8 INCHES. THE
SOUTHERN LARAMIE RANGE COULD GET CLOSE TO A FOOT AS WELL. THE NEXT
SHIFT MAY UPGRADE AND/OR EXTEND THE WINTER HEADLINES AFTER LOOKING
AT THE 12Z/18Z MODEL GUIDANCE.

HIGHS TODAY WILL BE SIMILAR TO SATURDAY WITH MOSTLY UPPER TEENS TO
UPPER 20S. LOWS TONIGHT AND MONDAY NIGHT WILL AVERAGE IN THE TEENS.
MONDAY WILL BE MILDER WITH SOUTHWESTERLY WINDS. EXPECT HIGHS IN THE
30S TO AROUND 40. TEMPERATURES TUESDAY WILL NOT RISE MUCH FROM THE
EARLY MORNING LOWS...AND WILL BE FALLING THROUGH THE DAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM MST SUN MAR 1 2015

THE MAIN CHALLENGE IN THE EXTENDED WILL BE TEMPERATURE TRENDS AS WE
STILL ANTICIPATE A BAND OF NEW SNOWPACK SOMEWHERE IN THE CWA. GFS/EC
BOTH SHOW A SECONDARY SHORTWAVE DIVING ACROSS WY BETWEEN 00Z AND 12Z
WED. MODEST PVA SHOULD BE ENOUGH FOR SNOW SHOWERS TO LINGER INTO WED
MORNING OR PERHAPS EARLY AFTERNOON. MEDIUM RANGE 700-300 MILLIBAR RH
PROGS SUGGEST A DRYING COLUMN BY THIS TIME...SO EXPECT LESS THAN AN
INCH OF ADDITIONAL ACCUMULATION OVER THE LOWER ELEVATIONS AFTER 00Z
WED. TEMPERATURES WILL BE TRICKY ON TUE NIGHT AS CLOUDS WILL PREVENT
SIGNIFICANT RADIATIONAL COOLING. HOWEVER...MODELS AGREE WITH STRONG
LOW LEVEL COLD ADVECTION PUSHING H7 TEMPS AS LOW AS -20 DEG C BY 12Z
WED PER THE EURO. GIVEN AN AIR MASS THIS COLD...CONFIDENCE IS FAIRLY
HIGH THAT MANY AREAS WILL BE BELOW ZERO FOR LOWS. DID NOT STRAY TOO
FAR AWAY FROM GUIDANCE THOUGH. COOLEST TEMPERATURES ON WED SHOULD BE
FOUND OVER THE MOST SUBSTANTIAL SNOWPACK. GUIDANCE SUGGESTS THE BEST
CHANCE FOR LOW-ELEVATION SIGNIFICANT SNOWFALL EARLY IN THE WEEK WILL
BE WEST OF THE LARAMIE RANGE...SO UNDERCUT MOS BY SEVERAL DEGREES IN
THOSE AREAS. KEPT HIGHS BELOW GUIDANCE ACROSS THE BOARD WITH MUCH OF
THE AREA LIKELY TO RECEIVE ACCUMULATING SNOW IN THE SHORT TERM.

IMPROVING TEMPERATURES LATER IN THE WEEK AS UPPER-LEVEL RIDGING AND
LOW LEVEL DOWNSLOPE RETURN TO THE REGION. A BACK DOOR COLD FRONT IS
PROGGED TO SINK SOUTHWARD ON FRI AFTERNOON...POSSIBLY HAVING A SMALL
IMPACT ON HIGHS WITH COLD ADVECTION ALOFT. CANNOT RULE OUT ISOLATED
RAIN OR SNOW SHOWERS ON FRI NIGHT OR SAT MORNING WITH THE ARRIVAL OF
BETTER MID LEVEL SUPPORT. HOWEVER...KEPT THE FORECAST DRY FOR NOW AS
THIS SYSTEM LOOKS TO BE A BIT MOISTURE STARVED. STILL EXPECT A WINDY
PERIOD FROM WED NIGHT THROUGH FRI OVER THE WIND PRONE AREAS. THE GFS
HAS BEEN CONSISTENT WITH A STRONG H85 CAG-CPR GRADIENT IN EXCESS OF
60 METERS AND 45 TO 50 KT FLOW OVER ARL AND BRX AT H75 THROUGH MUCH
OF THAT TIME PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 952 PM MST SAT FEB 28 2015

TOUGH FORECAST FOR OUR SOUTHEAST WYOMING AIRPORTS. RADAR SHOWING
AREA OF SNOW FILLING IN FROM KCYS TO KLAR...BUT IT IS NOT TOO HEAVY
AND BARELY RESTRICTING VISIBILITIES. GOING TO HOLD OFF LOWERING
CONDITIONS UNTIL AFTER 12Z AND CONFINE LOWER CONDITIONS TO KLAR.

&&

.FIRE WEATHER...
ISSUED AT 321 AM MST SUN MAR 1 2015

A WEAK UPPER LEVEL DISTURBANCE WILL PRODUCE LIGHT SNOW EARLY THIS
MORNING OVER FAR SOUTHEAST WYOMING AND SOUTHERN NEBRASKA PANHANDLE.
A LOW PRESSURE SYSTEM AND ASSOCIATED UPPER LEVEL TROUGH WILL APPROACH
FROM THE SOUTHWEST TONIGHT AND MONDAY...AND MOVE ACROSS THE CENTRAL
ROCKIES MONDAY NIGHT AND TUESDAY. SNOW WILL DEVELOP TONIGHT ACROSS
SOUTH CENTRAL WYOMING AND BECOME MORE WIDESPREAD MONDAY AND MONDAY
NIGHT. THE SNOW WILL BE HEAVY AT TIMES...ESPECIALLY OVER THE HIGHER
TERRAIN. THE SNOW WILL TAPER OFF TUESDAY NIGHT. A ARCTIC COLD FRONT
WILL PLUNGE SOUTH THROUGH THE DISTRICT MONDAY NIGHT. BITTERLY COLD
TEMPERATURES AND WIND CHILLS WILL PREVAIL TUESDAY THROUGH WEDNESDAY
BEFORE GRADUALLY MODERATING TEMPERATURES LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE TUESDAY NIGHT
     FOR WYZ111>114.

NE...NONE.
&&

$$

SHORT TERM...MAJ
LONG TERM...CLH
AVIATION...GCC
FIRE WEATHER...MAJ



000
FXUS65 KCYS 011106
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
406 AM MST SUN MAR 1 2015

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 400 AM MST SUN MAR 1 2015

LATEST GOES WATER VAPOR IMAGERY SHOWED THE SPLIT CLOSED UPPER LOW
SLOWLY SINKING SOUTHEAST ALONG THE CENTRAL CA COAST. THE BASE OF
THE NORTHERN STREAM TROUGH WAS MOVING EAST ACROSS THE DAKOTAS. A
DEFORMATION ZONE STRETCHED NORTHEAST TO SOUTHWEST FROM WESTERN NE
ACROSS NORTHERN CO. NARROW BAND OF UPPER LIFT COMBINED WITH MOISTURE
AND WEAK UPSLOPE RESULTED IN AN AREA OF LIGHT SNOW OVER PORTIONS
OF SOUTHEAST WY AND WESTERN NE. HRRR MODEL PROGS THIS AREA TO WEAKEN
AS IT MOVES FURTHER EAST THROUGH DAYBREAK. TEMPERATURES WERE IN THE
SINGLE DIGITS AND TEENS WITH LIGHT WINDS.

FORECAST CONCERNS DURING THE SHORT TERM WILL FOCUS ON THE DEVELOPING
WINTER STORM AND ITS IMPACTS ON OUR AREA...PARTICULARLY FROM LATE
TONIGHT THROUGH TUESDAY. CLOSED UPPER LOW NEAR SOUTHERN CA COAST
GRADUALLY OPENS UP AND EJECTS NORTHEAST AS ANOTHER SHORTWAVE DROPS
SOUTH ALONG THE CA COAST DURING THE NEXT 24 TO 48 HOURS. THE MODEL
CONSENSUS PROGS A LOW PRESSURE SYSTEM TO FORM NEAR THE FOUR CORNERS
REGION AND TRACK NORTHEAST ACROSS COLORADO. LIGHT SNOW REDEVELOPS
LATER TODAY OVER THE SOUTHERN MOUNTAINS AND BECOMES MORE WIDESPREAD
AND HEAVIER LATE TONIGHT INTO MONDAY. THE GFS IS SLIGHTLY DEEPER
AND FASTER THAN THE ECMWF WITH REGARDS TO THE SURFACE LOW AND ITS
MOTION. THEY ARE SIMILAR WITH THE EASTWARD TRACK OF THE LOW INTO
THE CENTRAL PLAINS EARLY TUESDAY MORNING. THEY ALSO AGREE WITH THE
ARCTIC COLD FRONTAL PASSAGE DURING THIS TIME PERIOD. WINDS SHIFT
TO NORTHERLY AND BECOME GUSTY TUESDAY. SNOW WILL BE WIDESPREAD
OVER THE CWA MONDAY NIGHT AND TUESDAY. THE COMBINATION OF FALLING
AND BLOWING SNOW WILL RESULT IN HAZARDOUS TRAVEL WEST OF THE
LARAMIE RANGE...ESPECIALLY MONDAY THROUGH TUESDAY. LATEST WPC
GUIDANCE PROGS 1-2 FT OF SNOW FOR THE SNOWY/SIERRA MADRE RANGES
WITH UP TO A FOOT FOR THE NEARBY VALLEYS. ISSUED A WINTER STORM
WATCH FOR WY ZONES 111-114 LATE TONIGHT THROUGH LATE TUESDAY NIGHT
FOR THE POTENTIAL OF HEAVY SNOW. FURTHER NORTH AND EAST...WE`RE
LOOKING AT ADVISORY ACCUMULATIONS...GENERALLY 4-8 INCHES. THE
SOUTHERN LARAMIE RANGE COULD GET CLOSE TO A FOOT AS WELL. THE NEXT
SHIFT MAY UPGRADE AND/OR EXTEND THE WINTER HEADLINES AFTER LOOKING
AT THE 12Z/18Z MODEL GUIDANCE.

HIGHS TODAY WILL BE SIMILAR TO SATURDAY WITH MOSTLY UPPER TEENS TO
UPPER 20S. LOWS TONIGHT AND MONDAY NIGHT WILL AVERAGE IN THE TEENS.
MONDAY WILL BE MILDER WITH SOUTHWESTERLY WINDS. EXPECT HIGHS IN THE
30S TO AROUND 40. TEMPERATURES TUESDAY WILL NOT RISE MUCH FROM THE
EARLY MORNING LOWS...AND WILL BE FALLING THROUGH THE DAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM MST SUN MAR 1 2015

THE MAIN CHALLENGE IN THE EXTENDED WILL BE TEMPERATURE TRENDS AS WE
STILL ANTICIPATE A BAND OF NEW SNOWPACK SOMEWHERE IN THE CWA. GFS/EC
BOTH SHOW A SECONDARY SHORTWAVE DIVING ACROSS WY BETWEEN 00Z AND 12Z
WED. MODEST PVA SHOULD BE ENOUGH FOR SNOW SHOWERS TO LINGER INTO WED
MORNING OR PERHAPS EARLY AFTERNOON. MEDIUM RANGE 700-300 MILLIBAR RH
PROGS SUGGEST A DRYING COLUMN BY THIS TIME...SO EXPECT LESS THAN AN
INCH OF ADDITIONAL ACCUMULATION OVER THE LOWER ELEVATIONS AFTER 00Z
WED. TEMPERATURES WILL BE TRICKY ON TUE NIGHT AS CLOUDS WILL PREVENT
SIGNIFICANT RADIATIONAL COOLING. HOWEVER...MODELS AGREE WITH STRONG
LOW LEVEL COLD ADVECTION PUSHING H7 TEMPS AS LOW AS -20 DEG C BY 12Z
WED PER THE EURO. GIVEN AN AIR MASS THIS COLD...CONFIDENCE IS FAIRLY
HIGH THAT MANY AREAS WILL BE BELOW ZERO FOR LOWS. DID NOT STRAY TOO
FAR AWAY FROM GUIDANCE THOUGH. COOLEST TEMPERATURES ON WED SHOULD BE
FOUND OVER THE MOST SUBSTANTIAL SNOWPACK. GUIDANCE SUGGESTS THE BEST
CHANCE FOR LOW-ELEVATION SIGNIFICANT SNOWFALL EARLY IN THE WEEK WILL
BE WEST OF THE LARAMIE RANGE...SO UNDERCUT MOS BY SEVERAL DEGREES IN
THOSE AREAS. KEPT HIGHS BELOW GUIDANCE ACROSS THE BOARD WITH MUCH OF
THE AREA LIKELY TO RECEIVE ACCUMULATING SNOW IN THE SHORT TERM.

IMPROVING TEMPERATURES LATER IN THE WEEK AS UPPER-LEVEL RIDGING AND
LOW LEVEL DOWNSLOPE RETURN TO THE REGION. A BACK DOOR COLD FRONT IS
PROGGED TO SINK SOUTHWARD ON FRI AFTERNOON...POSSIBLY HAVING A SMALL
IMPACT ON HIGHS WITH COLD ADVECTION ALOFT. CANNOT RULE OUT ISOLATED
RAIN OR SNOW SHOWERS ON FRI NIGHT OR SAT MORNING WITH THE ARRIVAL OF
BETTER MID LEVEL SUPPORT. HOWEVER...KEPT THE FORECAST DRY FOR NOW AS
THIS SYSTEM LOOKS TO BE A BIT MOISTURE STARVED. STILL EXPECT A WINDY
PERIOD FROM WED NIGHT THROUGH FRI OVER THE WIND PRONE AREAS. THE GFS
HAS BEEN CONSISTENT WITH A STRONG H85 CAG-CPR GRADIENT IN EXCESS OF
60 METERS AND 45 TO 50 KT FLOW OVER ARL AND BRX AT H75 THROUGH MUCH
OF THAT TIME PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 952 PM MST SAT FEB 28 2015

TOUGH FORECAST FOR OUR SOUTHEAST WYOMING AIRPORTS. RADAR SHOWING
AREA OF SNOW FILLING IN FROM KCYS TO KLAR...BUT IT IS NOT TOO HEAVY
AND BARELY RESTRICTING VISIBILITIES. GOING TO HOLD OFF LOWERING
CONDITIONS UNTIL AFTER 12Z AND CONFINE LOWER CONDITIONS TO KLAR.

&&

.FIRE WEATHER...
ISSUED AT 321 AM MST SUN MAR 1 2015

A WEAK UPPER LEVEL DISTURBANCE WILL PRODUCE LIGHT SNOW EARLY THIS
MORNING OVER FAR SOUTHEAST WYOMING AND SOUTHERN NEBRASKA PANHANDLE.
A LOW PRESSURE SYSTEM AND ASSOCIATED UPPER LEVEL TROUGH WILL APPROACH
FROM THE SOUTHWEST TONIGHT AND MONDAY...AND MOVE ACROSS THE CENTRAL
ROCKIES MONDAY NIGHT AND TUESDAY. SNOW WILL DEVELOP TONIGHT ACROSS
SOUTH CENTRAL WYOMING AND BECOME MORE WIDESPREAD MONDAY AND MONDAY
NIGHT. THE SNOW WILL BE HEAVY AT TIMES...ESPECIALLY OVER THE HIGHER
TERRAIN. THE SNOW WILL TAPER OFF TUESDAY NIGHT. A ARCTIC COLD FRONT
WILL PLUNGE SOUTH THROUGH THE DISTRICT MONDAY NIGHT. BITTERLY COLD
TEMPERATURES AND WIND CHILLS WILL PREVAIL TUESDAY THROUGH WEDNESDAY
BEFORE GRADUALLY MODERATING TEMPERATURES LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE TUESDAY NIGHT
     FOR WYZ111>114.

NE...NONE.
&&

$$

SHORT TERM...MAJ
LONG TERM...CLH
AVIATION...GCC
FIRE WEATHER...MAJ



000
FXUS65 KCYS 011106
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
406 AM MST SUN MAR 1 2015

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 400 AM MST SUN MAR 1 2015

LATEST GOES WATER VAPOR IMAGERY SHOWED THE SPLIT CLOSED UPPER LOW
SLOWLY SINKING SOUTHEAST ALONG THE CENTRAL CA COAST. THE BASE OF
THE NORTHERN STREAM TROUGH WAS MOVING EAST ACROSS THE DAKOTAS. A
DEFORMATION ZONE STRETCHED NORTHEAST TO SOUTHWEST FROM WESTERN NE
ACROSS NORTHERN CO. NARROW BAND OF UPPER LIFT COMBINED WITH MOISTURE
AND WEAK UPSLOPE RESULTED IN AN AREA OF LIGHT SNOW OVER PORTIONS
OF SOUTHEAST WY AND WESTERN NE. HRRR MODEL PROGS THIS AREA TO WEAKEN
AS IT MOVES FURTHER EAST THROUGH DAYBREAK. TEMPERATURES WERE IN THE
SINGLE DIGITS AND TEENS WITH LIGHT WINDS.

FORECAST CONCERNS DURING THE SHORT TERM WILL FOCUS ON THE DEVELOPING
WINTER STORM AND ITS IMPACTS ON OUR AREA...PARTICULARLY FROM LATE
TONIGHT THROUGH TUESDAY. CLOSED UPPER LOW NEAR SOUTHERN CA COAST
GRADUALLY OPENS UP AND EJECTS NORTHEAST AS ANOTHER SHORTWAVE DROPS
SOUTH ALONG THE CA COAST DURING THE NEXT 24 TO 48 HOURS. THE MODEL
CONSENSUS PROGS A LOW PRESSURE SYSTEM TO FORM NEAR THE FOUR CORNERS
REGION AND TRACK NORTHEAST ACROSS COLORADO. LIGHT SNOW REDEVELOPS
LATER TODAY OVER THE SOUTHERN MOUNTAINS AND BECOMES MORE WIDESPREAD
AND HEAVIER LATE TONIGHT INTO MONDAY. THE GFS IS SLIGHTLY DEEPER
AND FASTER THAN THE ECMWF WITH REGARDS TO THE SURFACE LOW AND ITS
MOTION. THEY ARE SIMILAR WITH THE EASTWARD TRACK OF THE LOW INTO
THE CENTRAL PLAINS EARLY TUESDAY MORNING. THEY ALSO AGREE WITH THE
ARCTIC COLD FRONTAL PASSAGE DURING THIS TIME PERIOD. WINDS SHIFT
TO NORTHERLY AND BECOME GUSTY TUESDAY. SNOW WILL BE WIDESPREAD
OVER THE CWA MONDAY NIGHT AND TUESDAY. THE COMBINATION OF FALLING
AND BLOWING SNOW WILL RESULT IN HAZARDOUS TRAVEL WEST OF THE
LARAMIE RANGE...ESPECIALLY MONDAY THROUGH TUESDAY. LATEST WPC
GUIDANCE PROGS 1-2 FT OF SNOW FOR THE SNOWY/SIERRA MADRE RANGES
WITH UP TO A FOOT FOR THE NEARBY VALLEYS. ISSUED A WINTER STORM
WATCH FOR WY ZONES 111-114 LATE TONIGHT THROUGH LATE TUESDAY NIGHT
FOR THE POTENTIAL OF HEAVY SNOW. FURTHER NORTH AND EAST...WE`RE
LOOKING AT ADVISORY ACCUMULATIONS...GENERALLY 4-8 INCHES. THE
SOUTHERN LARAMIE RANGE COULD GET CLOSE TO A FOOT AS WELL. THE NEXT
SHIFT MAY UPGRADE AND/OR EXTEND THE WINTER HEADLINES AFTER LOOKING
AT THE 12Z/18Z MODEL GUIDANCE.

HIGHS TODAY WILL BE SIMILAR TO SATURDAY WITH MOSTLY UPPER TEENS TO
UPPER 20S. LOWS TONIGHT AND MONDAY NIGHT WILL AVERAGE IN THE TEENS.
MONDAY WILL BE MILDER WITH SOUTHWESTERLY WINDS. EXPECT HIGHS IN THE
30S TO AROUND 40. TEMPERATURES TUESDAY WILL NOT RISE MUCH FROM THE
EARLY MORNING LOWS...AND WILL BE FALLING THROUGH THE DAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM MST SUN MAR 1 2015

THE MAIN CHALLENGE IN THE EXTENDED WILL BE TEMPERATURE TRENDS AS WE
STILL ANTICIPATE A BAND OF NEW SNOWPACK SOMEWHERE IN THE CWA. GFS/EC
BOTH SHOW A SECONDARY SHORTWAVE DIVING ACROSS WY BETWEEN 00Z AND 12Z
WED. MODEST PVA SHOULD BE ENOUGH FOR SNOW SHOWERS TO LINGER INTO WED
MORNING OR PERHAPS EARLY AFTERNOON. MEDIUM RANGE 700-300 MILLIBAR RH
PROGS SUGGEST A DRYING COLUMN BY THIS TIME...SO EXPECT LESS THAN AN
INCH OF ADDITIONAL ACCUMULATION OVER THE LOWER ELEVATIONS AFTER 00Z
WED. TEMPERATURES WILL BE TRICKY ON TUE NIGHT AS CLOUDS WILL PREVENT
SIGNIFICANT RADIATIONAL COOLING. HOWEVER...MODELS AGREE WITH STRONG
LOW LEVEL COLD ADVECTION PUSHING H7 TEMPS AS LOW AS -20 DEG C BY 12Z
WED PER THE EURO. GIVEN AN AIR MASS THIS COLD...CONFIDENCE IS FAIRLY
HIGH THAT MANY AREAS WILL BE BELOW ZERO FOR LOWS. DID NOT STRAY TOO
FAR AWAY FROM GUIDANCE THOUGH. COOLEST TEMPERATURES ON WED SHOULD BE
FOUND OVER THE MOST SUBSTANTIAL SNOWPACK. GUIDANCE SUGGESTS THE BEST
CHANCE FOR LOW-ELEVATION SIGNIFICANT SNOWFALL EARLY IN THE WEEK WILL
BE WEST OF THE LARAMIE RANGE...SO UNDERCUT MOS BY SEVERAL DEGREES IN
THOSE AREAS. KEPT HIGHS BELOW GUIDANCE ACROSS THE BOARD WITH MUCH OF
THE AREA LIKELY TO RECEIVE ACCUMULATING SNOW IN THE SHORT TERM.

IMPROVING TEMPERATURES LATER IN THE WEEK AS UPPER-LEVEL RIDGING AND
LOW LEVEL DOWNSLOPE RETURN TO THE REGION. A BACK DOOR COLD FRONT IS
PROGGED TO SINK SOUTHWARD ON FRI AFTERNOON...POSSIBLY HAVING A SMALL
IMPACT ON HIGHS WITH COLD ADVECTION ALOFT. CANNOT RULE OUT ISOLATED
RAIN OR SNOW SHOWERS ON FRI NIGHT OR SAT MORNING WITH THE ARRIVAL OF
BETTER MID LEVEL SUPPORT. HOWEVER...KEPT THE FORECAST DRY FOR NOW AS
THIS SYSTEM LOOKS TO BE A BIT MOISTURE STARVED. STILL EXPECT A WINDY
PERIOD FROM WED NIGHT THROUGH FRI OVER THE WIND PRONE AREAS. THE GFS
HAS BEEN CONSISTENT WITH A STRONG H85 CAG-CPR GRADIENT IN EXCESS OF
60 METERS AND 45 TO 50 KT FLOW OVER ARL AND BRX AT H75 THROUGH MUCH
OF THAT TIME PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 952 PM MST SAT FEB 28 2015

TOUGH FORECAST FOR OUR SOUTHEAST WYOMING AIRPORTS. RADAR SHOWING
AREA OF SNOW FILLING IN FROM KCYS TO KLAR...BUT IT IS NOT TOO HEAVY
AND BARELY RESTRICTING VISIBILITIES. GOING TO HOLD OFF LOWERING
CONDITIONS UNTIL AFTER 12Z AND CONFINE LOWER CONDITIONS TO KLAR.

&&

.FIRE WEATHER...
ISSUED AT 321 AM MST SUN MAR 1 2015

A WEAK UPPER LEVEL DISTURBANCE WILL PRODUCE LIGHT SNOW EARLY THIS
MORNING OVER FAR SOUTHEAST WYOMING AND SOUTHERN NEBRASKA PANHANDLE.
A LOW PRESSURE SYSTEM AND ASSOCIATED UPPER LEVEL TROUGH WILL APPROACH
FROM THE SOUTHWEST TONIGHT AND MONDAY...AND MOVE ACROSS THE CENTRAL
ROCKIES MONDAY NIGHT AND TUESDAY. SNOW WILL DEVELOP TONIGHT ACROSS
SOUTH CENTRAL WYOMING AND BECOME MORE WIDESPREAD MONDAY AND MONDAY
NIGHT. THE SNOW WILL BE HEAVY AT TIMES...ESPECIALLY OVER THE HIGHER
TERRAIN. THE SNOW WILL TAPER OFF TUESDAY NIGHT. A ARCTIC COLD FRONT
WILL PLUNGE SOUTH THROUGH THE DISTRICT MONDAY NIGHT. BITTERLY COLD
TEMPERATURES AND WIND CHILLS WILL PREVAIL TUESDAY THROUGH WEDNESDAY
BEFORE GRADUALLY MODERATING TEMPERATURES LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE TUESDAY NIGHT
     FOR WYZ111>114.

NE...NONE.
&&

$$

SHORT TERM...MAJ
LONG TERM...CLH
AVIATION...GCC
FIRE WEATHER...MAJ



000
FXUS65 KCYS 011106
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
406 AM MST SUN MAR 1 2015

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 400 AM MST SUN MAR 1 2015

LATEST GOES WATER VAPOR IMAGERY SHOWED THE SPLIT CLOSED UPPER LOW
SLOWLY SINKING SOUTHEAST ALONG THE CENTRAL CA COAST. THE BASE OF
THE NORTHERN STREAM TROUGH WAS MOVING EAST ACROSS THE DAKOTAS. A
DEFORMATION ZONE STRETCHED NORTHEAST TO SOUTHWEST FROM WESTERN NE
ACROSS NORTHERN CO. NARROW BAND OF UPPER LIFT COMBINED WITH MOISTURE
AND WEAK UPSLOPE RESULTED IN AN AREA OF LIGHT SNOW OVER PORTIONS
OF SOUTHEAST WY AND WESTERN NE. HRRR MODEL PROGS THIS AREA TO WEAKEN
AS IT MOVES FURTHER EAST THROUGH DAYBREAK. TEMPERATURES WERE IN THE
SINGLE DIGITS AND TEENS WITH LIGHT WINDS.

FORECAST CONCERNS DURING THE SHORT TERM WILL FOCUS ON THE DEVELOPING
WINTER STORM AND ITS IMPACTS ON OUR AREA...PARTICULARLY FROM LATE
TONIGHT THROUGH TUESDAY. CLOSED UPPER LOW NEAR SOUTHERN CA COAST
GRADUALLY OPENS UP AND EJECTS NORTHEAST AS ANOTHER SHORTWAVE DROPS
SOUTH ALONG THE CA COAST DURING THE NEXT 24 TO 48 HOURS. THE MODEL
CONSENSUS PROGS A LOW PRESSURE SYSTEM TO FORM NEAR THE FOUR CORNERS
REGION AND TRACK NORTHEAST ACROSS COLORADO. LIGHT SNOW REDEVELOPS
LATER TODAY OVER THE SOUTHERN MOUNTAINS AND BECOMES MORE WIDESPREAD
AND HEAVIER LATE TONIGHT INTO MONDAY. THE GFS IS SLIGHTLY DEEPER
AND FASTER THAN THE ECMWF WITH REGARDS TO THE SURFACE LOW AND ITS
MOTION. THEY ARE SIMILAR WITH THE EASTWARD TRACK OF THE LOW INTO
THE CENTRAL PLAINS EARLY TUESDAY MORNING. THEY ALSO AGREE WITH THE
ARCTIC COLD FRONTAL PASSAGE DURING THIS TIME PERIOD. WINDS SHIFT
TO NORTHERLY AND BECOME GUSTY TUESDAY. SNOW WILL BE WIDESPREAD
OVER THE CWA MONDAY NIGHT AND TUESDAY. THE COMBINATION OF FALLING
AND BLOWING SNOW WILL RESULT IN HAZARDOUS TRAVEL WEST OF THE
LARAMIE RANGE...ESPECIALLY MONDAY THROUGH TUESDAY. LATEST WPC
GUIDANCE PROGS 1-2 FT OF SNOW FOR THE SNOWY/SIERRA MADRE RANGES
WITH UP TO A FOOT FOR THE NEARBY VALLEYS. ISSUED A WINTER STORM
WATCH FOR WY ZONES 111-114 LATE TONIGHT THROUGH LATE TUESDAY NIGHT
FOR THE POTENTIAL OF HEAVY SNOW. FURTHER NORTH AND EAST...WE`RE
LOOKING AT ADVISORY ACCUMULATIONS...GENERALLY 4-8 INCHES. THE
SOUTHERN LARAMIE RANGE COULD GET CLOSE TO A FOOT AS WELL. THE NEXT
SHIFT MAY UPGRADE AND/OR EXTEND THE WINTER HEADLINES AFTER LOOKING
AT THE 12Z/18Z MODEL GUIDANCE.

HIGHS TODAY WILL BE SIMILAR TO SATURDAY WITH MOSTLY UPPER TEENS TO
UPPER 20S. LOWS TONIGHT AND MONDAY NIGHT WILL AVERAGE IN THE TEENS.
MONDAY WILL BE MILDER WITH SOUTHWESTERLY WINDS. EXPECT HIGHS IN THE
30S TO AROUND 40. TEMPERATURES TUESDAY WILL NOT RISE MUCH FROM THE
EARLY MORNING LOWS...AND WILL BE FALLING THROUGH THE DAY IN THE
WAKE OF THE COLD FRONTAL PASSAGE.

.LONG TERM...(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 330 AM MST SUN MAR 1 2015

THE MAIN CHALLENGE IN THE EXTENDED WILL BE TEMPERATURE TRENDS AS WE
STILL ANTICIPATE A BAND OF NEW SNOWPACK SOMEWHERE IN THE CWA. GFS/EC
BOTH SHOW A SECONDARY SHORTWAVE DIVING ACROSS WY BETWEEN 00Z AND 12Z
WED. MODEST PVA SHOULD BE ENOUGH FOR SNOW SHOWERS TO LINGER INTO WED
MORNING OR PERHAPS EARLY AFTERNOON. MEDIUM RANGE 700-300 MILLIBAR RH
PROGS SUGGEST A DRYING COLUMN BY THIS TIME...SO EXPECT LESS THAN AN
INCH OF ADDITIONAL ACCUMULATION OVER THE LOWER ELEVATIONS AFTER 00Z
WED. TEMPERATURES WILL BE TRICKY ON TUE NIGHT AS CLOUDS WILL PREVENT
SIGNIFICANT RADIATIONAL COOLING. HOWEVER...MODELS AGREE WITH STRONG
LOW LEVEL COLD ADVECTION PUSHING H7 TEMPS AS LOW AS -20 DEG C BY 12Z
WED PER THE EURO. GIVEN AN AIR MASS THIS COLD...CONFIDENCE IS FAIRLY
HIGH THAT MANY AREAS WILL BE BELOW ZERO FOR LOWS. DID NOT STRAY TOO
FAR AWAY FROM GUIDANCE THOUGH. COOLEST TEMPERATURES ON WED SHOULD BE
FOUND OVER THE MOST SUBSTANTIAL SNOWPACK. GUIDANCE SUGGESTS THE BEST
CHANCE FOR LOW-ELEVATION SIGNIFICANT SNOWFALL EARLY IN THE WEEK WILL
BE WEST OF THE LARAMIE RANGE...SO UNDERCUT MOS BY SEVERAL DEGREES IN
THOSE AREAS. KEPT HIGHS BELOW GUIDANCE ACROSS THE BOARD WITH MUCH OF
THE AREA LIKELY TO RECEIVE ACCUMULATING SNOW IN THE SHORT TERM.

IMPROVING TEMPERATURES LATER IN THE WEEK AS UPPER-LEVEL RIDGING AND
LOW LEVEL DOWNSLOPE RETURN TO THE REGION. A BACK DOOR COLD FRONT IS
PROGGED TO SINK SOUTHWARD ON FRI AFTERNOON...POSSIBLY HAVING A SMALL
IMPACT ON HIGHS WITH COLD ADVECTION ALOFT. CANNOT RULE OUT ISOLATED
RAIN OR SNOW SHOWERS ON FRI NIGHT OR SAT MORNING WITH THE ARRIVAL OF
BETTER MID LEVEL SUPPORT. HOWEVER...KEPT THE FORECAST DRY FOR NOW AS
THIS SYSTEM LOOKS TO BE A BIT MOISTURE STARVED. STILL EXPECT A WINDY
PERIOD FROM WED NIGHT THROUGH FRI OVER THE WIND PRONE AREAS. THE GFS
HAS BEEN CONSISTENT WITH A STRONG H85 CAG-CPR GRADIENT IN EXCESS OF
60 METERS AND 45 TO 50 KT FLOW OVER ARL AND BRX AT H75 THROUGH MUCH
OF THAT TIME PERIOD.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 952 PM MST SAT FEB 28 2015

TOUGH FORECAST FOR OUR SOUTHEAST WYOMING AIRPORTS. RADAR SHOWING
AREA OF SNOW FILLING IN FROM KCYS TO KLAR...BUT IT IS NOT TOO HEAVY
AND BARELY RESTRICTING VISIBILITIES. GOING TO HOLD OFF LOWERING
CONDITIONS UNTIL AFTER 12Z AND CONFINE LOWER CONDITIONS TO KLAR.

&&

.FIRE WEATHER...
ISSUED AT 321 AM MST SUN MAR 1 2015

A WEAK UPPER LEVEL DISTURBANCE WILL PRODUCE LIGHT SNOW EARLY THIS
MORNING OVER FAR SOUTHEAST WYOMING AND SOUTHERN NEBRASKA PANHANDLE.
A LOW PRESSURE SYSTEM AND ASSOCIATED UPPER LEVEL TROUGH WILL APPROACH
FROM THE SOUTHWEST TONIGHT AND MONDAY...AND MOVE ACROSS THE CENTRAL
ROCKIES MONDAY NIGHT AND TUESDAY. SNOW WILL DEVELOP TONIGHT ACROSS
SOUTH CENTRAL WYOMING AND BECOME MORE WIDESPREAD MONDAY AND MONDAY
NIGHT. THE SNOW WILL BE HEAVY AT TIMES...ESPECIALLY OVER THE HIGHER
TERRAIN. THE SNOW WILL TAPER OFF TUESDAY NIGHT. A ARCTIC COLD FRONT
WILL PLUNGE SOUTH THROUGH THE DISTRICT MONDAY NIGHT. BITTERLY COLD
TEMPERATURES AND WIND CHILLS WILL PREVAIL TUESDAY THROUGH WEDNESDAY
BEFORE GRADUALLY MODERATING TEMPERATURES LATE IN THE WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...WINTER STORM WATCH FROM LATE TONIGHT THROUGH LATE TUESDAY NIGHT
     FOR WYZ111>114.

NE...NONE.
&&

$$

SHORT TERM...MAJ
LONG TERM...CLH
AVIATION...GCC
FIRE WEATHER...MAJ



000
FXUS63 KUNR 010938
AFDUNR

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

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 237 AM MST SUN MAR 1 2015

NW FLOW WILL PREVAIL IN THE PERIOD WITH A STRONG
PHASING SYSTEM ON TRACK MONDAY INTO TUES. A STRONG NW FLOW UPPER
LEVEL TROUGH WILL MERGE WITH THE EJECTING SW CONUS UPPER LEVEL
TROUGH...HELPING TO FORCE OF PERIOD OF LONG TRAJECTORY NORTHERLY
FLOW. THIS WILL SUPPORT ANOTHER ROUND OF ARCTIC AIR INTO THE
CONUS...ALONG WITH SOME SNOW AND WIND LOCALLY. A WEAKER SHORTWAVE
WILL TRAVERSE THE NORTHERN PLAINS TODAY...SUPPORTING REINFORCING
COLD THERMAL FIELDS. LACK OF MOISTURE WITH LARGE SCALE SINK
LOCALLY...EXPECTED TO SUPPORT DRY CONDS IN THE FA. INCREASING RETURN
FLOW FORCED BY SHORTWAVE RIDGING AHEAD OF THE APPROACHING STRONGER
NW FLOW IMPULSE...WILL SUPPORT A WARMER DAY MONDAY WITH CONTINUED
DRY CONDS...BEFORE SNOW AND WIND RETURN TO THE REGION MONDAY NIGHT.

TODAY...ANOTHER NW FLOW IMPULSE EXPECTED INTO THE REGION. ALTHOUGH
MOST IF NOT ALL OF THE LSA/UVM WILL PASS NORTH OF THE FA...CANNOT
RULE OUT A FEW HIGH BASED SNOW SHOWERS OVER THE NORTH HALF OF THE FA
AND OVER THE BLACK HILLS GIVEN FAIRLY STEEP LL LAPSE RATES.
HOWEVER...GIVEN DRY PROFILES...VIRGA WOULD BE ANTICIPATED THUS NO
POPS WARRANTED. STEEP LL LAPSE RATES PER INSOLATION AND MIXING WILL
FORCE FASTER FLOW DOWN SUPPORTING BREEZY CONDS...ESP ON THE SD
PLAINS WITH 15 TO 25 MPH WINDS EXPECTED. THERMAL FIELDS WILL
BASICALLY SEE NEAR NEUTRAL TEMP ADV...WITH TEMPS SIMILAR TO SAT/S
NUMBERS...SLIGHTLY WARMER. ASSOCIATED SFC HIGH WILL SHIFT SE OF THE
REGION TONIGHT...WITH GUSTY SOUTHERLY RETURN FLOW DEVELOPING OVER NE
WY AND PORTIONS OF THE SD PLAINS.

MONDAY...RETURN FLOW WILL REV UP WITH SOUTHERLY WINDS INCREASING
THROUGH THE DAY. WAA WILL BE ONGOING WITH MOST LOCATIONS SEEING 40S
FOR HIGHS...POSSIBLY NEAR 50 IN THE LEE OF THE BLACK HILLS. STRONG
NW FLOW UPPER TROUGH AND THE EJECTING SW CONUS UPPER LOW WILL
SUPPORT INCREASING LARGE SCALE ASCENT ACROSS THE SOUTHERN HALF OF
THE FA MONDAY EVENING WITH INCREASING MOISTURE AND FORCING
SUPPORTING INCREASING CHANCES FOR SNOW. BETTER CHANCES WILL ARRIVE
LATER MONDAY NIGHT AS A STRONG COLD FRONT IS FORCED THROUGH THE
FA...SUPPORTING INCREASING FGEN ACROSS MOST OF THE FA...ESP THE
SOUTHERN THIRD. DECENT LL MOISTURE COUPLED WITH MODEST FORCING WILL
AT LEAST SUPPORT UP TO A COUPLE INCHES OF SNOW ACROSS SCENTRAL
SD...WITH LESSER AMOUNTS OUTSIDE OF THE NORTHERN BLACK HILLS.
INCREASING FLOW WITH SUFFICIENT LL MOISTURE AND FORCING IN THE DGZ
WILL SUPPORT A GOOD PERIOD OF UPSLOPE IN THE NORTHERN HILLS WITH A
FEW INCHES POSSIBLE THERE BY TUE MORNING. STRONG CAA COUPLED WITH
FAST LL MOMENTUM WILL SUPPORT STRONG GUSTY WINDS NW WINDS ON THE SD
PLAINS EARLY TUES MORNING. ALTHOUGH SNOW AMOUNTS LOOK MINIMAL ON
THE PLAINS...BLOWING SNOW AND HAZARDOUS TRAVEL IS A CONCERN AND
WILL CERTAINLY NEED TO BE MONITORED WITH FUTURE FORECAST PACKAGES.
VERY COLD AIR WILL BEGIN TO ADVECT INTO THE REGION EARLY TUE MORNING
OVER THE NW HALF...WITH WINDCHILLS FALLING BELOW ZERO BY DAWN MOST
PLACES THERE.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 237 AM MST SUN MAR 1 2015

ARCTIC HIGH PRESSURE CONTINUES TO SURGE INTO THE NORTHERN PLAINS ON
TUESDAY...WITH STRONG NORTHWESTERLY WINDS PERSISTING THROUGH MUCH OF
THE DAY...AND TEMPERATURES STEADY OR CONTINUING TO FALL INTO THE
EVENING. LIGHT SNOW WILL BE LIKELY FROM NORTHEAST WYOMING THROUGH
SOUTHERN SOUTH DAKOTA...WITH SNOWFALL DIMINISHING FROM NORTH TO
SOUTH DURING THE DAY. TEMPERATURES WILL FALL BELOW ZERO ACROSS MUCH
OF THE AREA TUESDAY NIGHT.

THE BITTER COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP
IS EXPECTED. THIS NEXT WARM UP...HOWEVER...LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 237 AM MST SUN MAR 1 2015

LCL MVFR CIGS WILL BE POSSIBLE ACROSS NORTHEAST WYOMING AND THE
BLACK HILLS AREA THROUGH 18Z. OTHERWISE...VFR CONDITIONS ARE
EXPECTED THROUGH MONDAY MORNING.

&&

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

$$

SHORT TERM...JC
LONG TERM...15
AVIATION...15







000
FXUS63 KUNR 010938
AFDUNR

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

.SHORT TERM...TODAY THROUGH MONDAY NIGHT
ISSUED AT 237 AM MST SUN MAR 1 2015

NW FLOW WILL PREVAIL IN THE PERIOD WITH A STRONG
PHASING SYSTEM ON TRACK MONDAY INTO TUES. A STRONG NW FLOW UPPER
LEVEL TROUGH WILL MERGE WITH THE EJECTING SW CONUS UPPER LEVEL
TROUGH...HELPING TO FORCE OF PERIOD OF LONG TRAJECTORY NORTHERLY
FLOW. THIS WILL SUPPORT ANOTHER ROUND OF ARCTIC AIR INTO THE
CONUS...ALONG WITH SOME SNOW AND WIND LOCALLY. A WEAKER SHORTWAVE
WILL TRAVERSE THE NORTHERN PLAINS TODAY...SUPPORTING REINFORCING
COLD THERMAL FIELDS. LACK OF MOISTURE WITH LARGE SCALE SINK
LOCALLY...EXPECTED TO SUPPORT DRY CONDS IN THE FA. INCREASING RETURN
FLOW FORCED BY SHORTWAVE RIDGING AHEAD OF THE APPROACHING STRONGER
NW FLOW IMPULSE...WILL SUPPORT A WARMER DAY MONDAY WITH CONTINUED
DRY CONDS...BEFORE SNOW AND WIND RETURN TO THE REGION MONDAY NIGHT.

TODAY...ANOTHER NW FLOW IMPULSE EXPECTED INTO THE REGION. ALTHOUGH
MOST IF NOT ALL OF THE LSA/UVM WILL PASS NORTH OF THE FA...CANNOT
RULE OUT A FEW HIGH BASED SNOW SHOWERS OVER THE NORTH HALF OF THE FA
AND OVER THE BLACK HILLS GIVEN FAIRLY STEEP LL LAPSE RATES.
HOWEVER...GIVEN DRY PROFILES...VIRGA WOULD BE ANTICIPATED THUS NO
POPS WARRANTED. STEEP LL LAPSE RATES PER INSOLATION AND MIXING WILL
FORCE FASTER FLOW DOWN SUPPORTING BREEZY CONDS...ESP ON THE SD
PLAINS WITH 15 TO 25 MPH WINDS EXPECTED. THERMAL FIELDS WILL
BASICALLY SEE NEAR NEUTRAL TEMP ADV...WITH TEMPS SIMILAR TO SAT/S
NUMBERS...SLIGHTLY WARMER. ASSOCIATED SFC HIGH WILL SHIFT SE OF THE
REGION TONIGHT...WITH GUSTY SOUTHERLY RETURN FLOW DEVELOPING OVER NE
WY AND PORTIONS OF THE SD PLAINS.

MONDAY...RETURN FLOW WILL REV UP WITH SOUTHERLY WINDS INCREASING
THROUGH THE DAY. WAA WILL BE ONGOING WITH MOST LOCATIONS SEEING 40S
FOR HIGHS...POSSIBLY NEAR 50 IN THE LEE OF THE BLACK HILLS. STRONG
NW FLOW UPPER TROUGH AND THE EJECTING SW CONUS UPPER LOW WILL
SUPPORT INCREASING LARGE SCALE ASCENT ACROSS THE SOUTHERN HALF OF
THE FA MONDAY EVENING WITH INCREASING MOISTURE AND FORCING
SUPPORTING INCREASING CHANCES FOR SNOW. BETTER CHANCES WILL ARRIVE
LATER MONDAY NIGHT AS A STRONG COLD FRONT IS FORCED THROUGH THE
FA...SUPPORTING INCREASING FGEN ACROSS MOST OF THE FA...ESP THE
SOUTHERN THIRD. DECENT LL MOISTURE COUPLED WITH MODEST FORCING WILL
AT LEAST SUPPORT UP TO A COUPLE INCHES OF SNOW ACROSS SCENTRAL
SD...WITH LESSER AMOUNTS OUTSIDE OF THE NORTHERN BLACK HILLS.
INCREASING FLOW WITH SUFFICIENT LL MOISTURE AND FORCING IN THE DGZ
WILL SUPPORT A GOOD PERIOD OF UPSLOPE IN THE NORTHERN HILLS WITH A
FEW INCHES POSSIBLE THERE BY TUE MORNING. STRONG CAA COUPLED WITH
FAST LL MOMENTUM WILL SUPPORT STRONG GUSTY WINDS NW WINDS ON THE SD
PLAINS EARLY TUES MORNING. ALTHOUGH SNOW AMOUNTS LOOK MINIMAL ON
THE PLAINS...BLOWING SNOW AND HAZARDOUS TRAVEL IS A CONCERN AND
WILL CERTAINLY NEED TO BE MONITORED WITH FUTURE FORECAST PACKAGES.
VERY COLD AIR WILL BEGIN TO ADVECT INTO THE REGION EARLY TUE MORNING
OVER THE NW HALF...WITH WINDCHILLS FALLING BELOW ZERO BY DAWN MOST
PLACES THERE.

.LONG TERM...TUESDAY THROUGH SATURDAY
ISSUED AT 237 AM MST SUN MAR 1 2015

ARCTIC HIGH PRESSURE CONTINUES TO SURGE INTO THE NORTHERN PLAINS ON
TUESDAY...WITH STRONG NORTHWESTERLY WINDS PERSISTING THROUGH MUCH OF
THE DAY...AND TEMPERATURES STEADY OR CONTINUING TO FALL INTO THE
EVENING. LIGHT SNOW WILL BE LIKELY FROM NORTHEAST WYOMING THROUGH
SOUTHERN SOUTH DAKOTA...WITH SNOWFALL DIMINISHING FROM NORTH TO
SOUTH DURING THE DAY. TEMPERATURES WILL FALL BELOW ZERO ACROSS MUCH
OF THE AREA TUESDAY NIGHT.

THE BITTER COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP
IS EXPECTED. THIS NEXT WARM UP...HOWEVER...LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING
ISSUED AT 237 AM MST SUN MAR 1 2015

LCL MVFR CIGS WILL BE POSSIBLE ACROSS NORTHEAST WYOMING AND THE
BLACK HILLS AREA THROUGH 18Z. OTHERWISE...VFR CONDITIONS ARE
EXPECTED THROUGH MONDAY MORNING.

&&

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

$$

SHORT TERM...JC
LONG TERM...15
AVIATION...15






000
FXUS65 KRIW 010911
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
211 AM MST SUN MAR 1 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

AN INTERESTING FORECAST PERIOD ACROSS WESTERN AND CENTRAL WYOMING. A
FAIRLY QUIET BEGINNING AS LINGER ACTIVITY OTHER SOUTHERN WYOMING
TAPERS OFF THIS MORNING. MORNING INVERSIONS WILL DEVELOP...WITH
PATCHY FOG POSSIBLE ACROSS MUCH OF THE LOW LYING AREAS.

A BRIEF PERIOD OF DRY CONDITIONS ANTICIPATED THROUGH THE OVERNIGHT
HOURS. WHILE THE DRY PERIOD IS ONGOING...AN AREA OF LOW PRESSURE
WILL MOVE SOUTH ALONG THE PACIFIC COASTLINE...FINALLY HEADING INLAND
TOWARDS THE FOUR CORNERS REGION LATE TONIGHT AND INTO MONDAY. AS
THIS SYSTEM PROGRESSES IT WILL SEND SNOWFALL ACROSS THE SOUTHERN
THIRD OF THE FORECAST AREA...ESPECIALLY IMPACTING SOUTHERN
SWEETWATER COUNTY BY MONDAY MORNING. SNOWFALL WILL INCREASE MONDAY
AFTERNOON AND MONDAY NIGHT...AND IS FAVORABLE TO BECOME HEAVY AT
TIMES. SNOWFALL ACCUMULATIONS OF 4 TO 7 INCHES ARE POSSIBLE BY
TUESDAY EVENING...AND ARE SUPPORTED BY NATIONAL CENTERS. SOME
HIGHER AMOUNTS ARE POSSIBLE SOUTH OF INTERSTATE 80. WITH CONCERNS
RELATING TO THIS SYSTEM MOUNTING...HAVE ISSUED A WINTER STORM WATCH
FOR THE COUNTY. INTERSTATE 80 WILL BE IMPACTED...THOUGH AGAIN...THE
GREATEST AREA OF IMPACT LOOKS TO BE SOUTH OF THE
INTERSTATE...ESPECIALLY ALONG THE WYOMING AND COLORADO BORDER.

AS THIS SYSTEM IS IMPACTING THE SOUTHERN PORTION OF THE FORECAST
AREA... A WAVE OF LOW PRESSURE LOOKS TO SEND A CANADIAN SYSTEM INTO
NORTHERN WYOMING BY LATE MONDAY NIGHT. SNOWFALL WITH THIS SYSTEM
WILL ESPECIALLY IMPACT THE NORTHERN MOUNTAINS...AND WILL CONTINUE TO
BE MONITORED. EVENTUALLY...THE NORTHERN SYSTEM LOOKS TO TAKE OVER
THE SOUTHERN SYSTEM...WITH SNOWFALL SPREADING TO INCLUDE THE VAST
MAJORITY OF THE FORECAST AREA DURING THE VERY EARLY MORNING HOURS OF
TUESDAY. ALL SITUATIONS WILL CONTINUE TO BE MONITORED...THOUGH
REGARDLESS EVEN TO AMOUNTS...EXPECT A RETURN TO COOLER WEATHER WITH
SNOWFALL VERY FAVORABLE OVER THE AREA.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

NORTHWEST FLOW IS EXPECTED TO DOMINATE THE EXTENDED WITH AT LEAST
ONE DISTINCT SHORTWAVE TROUGH AND ASSOCIATED WEAK COLD FRONT SLIDING
ACROSS THE AREA IN THE FRIDAY/FRIDAY NIGHT TIME FRAME. OTHERWISE...A
RELATIVELY DRY NORTHWEST FLOW IS EXPECTED. WILL INTRODUCE SLIGHT
MOUNTAIN POPS FOR THIS SYSTEM FRIDAY/FRIDAY NIGHT...BUT KEPT THE
LOWER ELEVATIONS DRY FOR NOW...AS THIS SYSTEM APPEARS TO HAVE
LIMITED AVAILABLE MOISTURE.  CANNOT RULE OUT ISOLATED MOUNTAIN SNOW
SHOWERS ON OTHER DAYS MAINLY OVER THE NORTHWEST/NORTHERN
MOUNTAINS...BUT PREVIOUS FORECASTS WERE DRY...AND MOISTURE IS NOT
EXCITING...THUS HAVE KEPT THE ONGOING DRY FORECAST.

TEMPERATURES ON WEDNESDAY WILL BE 15 TO 25 DEGREES BELOW
AVERAGE...WITH SOME AREAS SEEING HIGHS ABOUT 30 DEGREES BELOW
AVERAGE. A WARMING TREND WILL OCCUR LATE THIS WEEK WITH MOST AREAS
RETURNING TO SEASONAL LEVELS BY FRIDAY. THE EXCEPTION WILL PROBABLY
BE TYPICAL TRAPPED CENTRAL BASINS WHERE MODELS TEND TO WARM THEM UP
TOO QUICKLY. A WEAK COLD FRONT FRIDAY/FRIDAY NIGHT...MIGHT ACTUALLY
HELP MIX OUT THOSE TRAPPED BASINS.

&&

.AVIATION.../12Z ISSUANCE/

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

VFR TO MVFR CONDITIONS WILL OCCUR THROUGH 18Z WITH AREAS OF LOW
CLOUDS AND FLURRIES TO LIGHT SNOW. EXPECT SOME MOUNTAIN OBSCURATION
UNTIL 18Z AS WELL. VFR CONDITIONS WILL PREVAIL BY 21Z AND THEN
THROUGH 12Z MONDAY.

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

OVER THE SOUTH UNTIL 15Z VFR TO MVFR CONDITIONS WILL OCCUR DUE TO
LOWER CLOUDS AND AREAS OF LIGHT SNOW. LOW CLOUDS WILL LINGER IN SOME
AREAS UNTIL 19Z. AFTER 22Z VFR CONDITIONS WILL PREVAIL OVER THE
REGION THROUGH 12Z MONDAY.

KPNA...KBPI AND KJAC AIRPORTS WILL SEE VFR CONDITIONS PREVAIL THROUGH
THE FORECAST PERIOD.

&&

.FIRE WEATHER...

ANOTHER RETURN TO WINTER EXPECTED OVER THE NEXT FEW DAYS. GENERALLY
DRY CONDITIONS ANTICIPATED TODAY...WITH MORNING INVERSIONS AND
RELATED PATCHY FOG POSSIBLE. A WINTRY SYSTEM WILL THEN MOVE INTO
SOUTHERN WYOMING MONDAY MORNING...SPREADING SNOWFALL ACROSS
SWEETWATER COUNTY. ANOTHER SYSTEM WILL THEN MOVE INTO NORTHERN
WYOMING MONDAY NIGHT SPREADING SNOWFALL ACROSS THE NORTHERN THIRD OF
THE FORECAST AREA. THESE TWO SYSTEM ARE EXPECTED TO JOIN DURING THE
VERY EARLY MORNING OF TUESDAY...WITH WIDESPREAD SNOWFALL
ANTICIPATED. IT APPEARS AS THOUGH THE GREATEST SNOWFALL AMOUNTS MAY
FALL OVER SOUTHERN WYOMING...WITH A WINTER STORM WATCH ISSUED FOR
THE AREA. STAY TUNED FOR UPDATES TO THIS UPCOMING STORM SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
WYZ028>030.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...AR
FIRE WEATHER...BRANHAM







000
FXUS65 KRIW 010911
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
211 AM MST SUN MAR 1 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

AN INTERESTING FORECAST PERIOD ACROSS WESTERN AND CENTRAL WYOMING. A
FAIRLY QUIET BEGINNING AS LINGER ACTIVITY OTHER SOUTHERN WYOMING
TAPERS OFF THIS MORNING. MORNING INVERSIONS WILL DEVELOP...WITH
PATCHY FOG POSSIBLE ACROSS MUCH OF THE LOW LYING AREAS.

A BRIEF PERIOD OF DRY CONDITIONS ANTICIPATED THROUGH THE OVERNIGHT
HOURS. WHILE THE DRY PERIOD IS ONGOING...AN AREA OF LOW PRESSURE
WILL MOVE SOUTH ALONG THE PACIFIC COASTLINE...FINALLY HEADING INLAND
TOWARDS THE FOUR CORNERS REGION LATE TONIGHT AND INTO MONDAY. AS
THIS SYSTEM PROGRESSES IT WILL SEND SNOWFALL ACROSS THE SOUTHERN
THIRD OF THE FORECAST AREA...ESPECIALLY IMPACTING SOUTHERN
SWEETWATER COUNTY BY MONDAY MORNING. SNOWFALL WILL INCREASE MONDAY
AFTERNOON AND MONDAY NIGHT...AND IS FAVORABLE TO BECOME HEAVY AT
TIMES. SNOWFALL ACCUMULATIONS OF 4 TO 7 INCHES ARE POSSIBLE BY
TUESDAY EVENING...AND ARE SUPPORTED BY NATIONAL CENTERS. SOME
HIGHER AMOUNTS ARE POSSIBLE SOUTH OF INTERSTATE 80. WITH CONCERNS
RELATING TO THIS SYSTEM MOUNTING...HAVE ISSUED A WINTER STORM WATCH
FOR THE COUNTY. INTERSTATE 80 WILL BE IMPACTED...THOUGH AGAIN...THE
GREATEST AREA OF IMPACT LOOKS TO BE SOUTH OF THE
INTERSTATE...ESPECIALLY ALONG THE WYOMING AND COLORADO BORDER.

AS THIS SYSTEM IS IMPACTING THE SOUTHERN PORTION OF THE FORECAST
AREA... A WAVE OF LOW PRESSURE LOOKS TO SEND A CANADIAN SYSTEM INTO
NORTHERN WYOMING BY LATE MONDAY NIGHT. SNOWFALL WITH THIS SYSTEM
WILL ESPECIALLY IMPACT THE NORTHERN MOUNTAINS...AND WILL CONTINUE TO
BE MONITORED. EVENTUALLY...THE NORTHERN SYSTEM LOOKS TO TAKE OVER
THE SOUTHERN SYSTEM...WITH SNOWFALL SPREADING TO INCLUDE THE VAST
MAJORITY OF THE FORECAST AREA DURING THE VERY EARLY MORNING HOURS OF
TUESDAY. ALL SITUATIONS WILL CONTINUE TO BE MONITORED...THOUGH
REGARDLESS EVEN TO AMOUNTS...EXPECT A RETURN TO COOLER WEATHER WITH
SNOWFALL VERY FAVORABLE OVER THE AREA.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

NORTHWEST FLOW IS EXPECTED TO DOMINATE THE EXTENDED WITH AT LEAST
ONE DISTINCT SHORTWAVE TROUGH AND ASSOCIATED WEAK COLD FRONT SLIDING
ACROSS THE AREA IN THE FRIDAY/FRIDAY NIGHT TIME FRAME. OTHERWISE...A
RELATIVELY DRY NORTHWEST FLOW IS EXPECTED. WILL INTRODUCE SLIGHT
MOUNTAIN POPS FOR THIS SYSTEM FRIDAY/FRIDAY NIGHT...BUT KEPT THE
LOWER ELEVATIONS DRY FOR NOW...AS THIS SYSTEM APPEARS TO HAVE
LIMITED AVAILABLE MOISTURE.  CANNOT RULE OUT ISOLATED MOUNTAIN SNOW
SHOWERS ON OTHER DAYS MAINLY OVER THE NORTHWEST/NORTHERN
MOUNTAINS...BUT PREVIOUS FORECASTS WERE DRY...AND MOISTURE IS NOT
EXCITING...THUS HAVE KEPT THE ONGOING DRY FORECAST.

TEMPERATURES ON WEDNESDAY WILL BE 15 TO 25 DEGREES BELOW
AVERAGE...WITH SOME AREAS SEEING HIGHS ABOUT 30 DEGREES BELOW
AVERAGE. A WARMING TREND WILL OCCUR LATE THIS WEEK WITH MOST AREAS
RETURNING TO SEASONAL LEVELS BY FRIDAY. THE EXCEPTION WILL PROBABLY
BE TYPICAL TRAPPED CENTRAL BASINS WHERE MODELS TEND TO WARM THEM UP
TOO QUICKLY. A WEAK COLD FRONT FRIDAY/FRIDAY NIGHT...MIGHT ACTUALLY
HELP MIX OUT THOSE TRAPPED BASINS.

&&

.AVIATION.../12Z ISSUANCE/

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

VFR TO MVFR CONDITIONS WILL OCCUR THROUGH 18Z WITH AREAS OF LOW
CLOUDS AND FLURRIES TO LIGHT SNOW. EXPECT SOME MOUNTAIN OBSCURATION
UNTIL 18Z AS WELL. VFR CONDITIONS WILL PREVAIL BY 21Z AND THEN
THROUGH 12Z MONDAY.

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

OVER THE SOUTH UNTIL 15Z VFR TO MVFR CONDITIONS WILL OCCUR DUE TO
LOWER CLOUDS AND AREAS OF LIGHT SNOW. LOW CLOUDS WILL LINGER IN SOME
AREAS UNTIL 19Z. AFTER 22Z VFR CONDITIONS WILL PREVAIL OVER THE
REGION THROUGH 12Z MONDAY.

KPNA...KBPI AND KJAC AIRPORTS WILL SEE VFR CONDITIONS PREVAIL THROUGH
THE FORECAST PERIOD.

&&

.FIRE WEATHER...

ANOTHER RETURN TO WINTER EXPECTED OVER THE NEXT FEW DAYS. GENERALLY
DRY CONDITIONS ANTICIPATED TODAY...WITH MORNING INVERSIONS AND
RELATED PATCHY FOG POSSIBLE. A WINTRY SYSTEM WILL THEN MOVE INTO
SOUTHERN WYOMING MONDAY MORNING...SPREADING SNOWFALL ACROSS
SWEETWATER COUNTY. ANOTHER SYSTEM WILL THEN MOVE INTO NORTHERN
WYOMING MONDAY NIGHT SPREADING SNOWFALL ACROSS THE NORTHERN THIRD OF
THE FORECAST AREA. THESE TWO SYSTEM ARE EXPECTED TO JOIN DURING THE
VERY EARLY MORNING OF TUESDAY...WITH WIDESPREAD SNOWFALL
ANTICIPATED. IT APPEARS AS THOUGH THE GREATEST SNOWFALL AMOUNTS MAY
FALL OVER SOUTHERN WYOMING...WITH A WINTER STORM WATCH ISSUED FOR
THE AREA. STAY TUNED FOR UPDATES TO THIS UPCOMING STORM SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
WYZ028>030.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...AR
FIRE WEATHER...BRANHAM







000
FXUS65 KRIW 010911
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
211 AM MST SUN MAR 1 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

AN INTERESTING FORECAST PERIOD ACROSS WESTERN AND CENTRAL WYOMING. A
FAIRLY QUIET BEGINNING AS LINGER ACTIVITY OTHER SOUTHERN WYOMING
TAPERS OFF THIS MORNING. MORNING INVERSIONS WILL DEVELOP...WITH
PATCHY FOG POSSIBLE ACROSS MUCH OF THE LOW LYING AREAS.

A BRIEF PERIOD OF DRY CONDITIONS ANTICIPATED THROUGH THE OVERNIGHT
HOURS. WHILE THE DRY PERIOD IS ONGOING...AN AREA OF LOW PRESSURE
WILL MOVE SOUTH ALONG THE PACIFIC COASTLINE...FINALLY HEADING INLAND
TOWARDS THE FOUR CORNERS REGION LATE TONIGHT AND INTO MONDAY. AS
THIS SYSTEM PROGRESSES IT WILL SEND SNOWFALL ACROSS THE SOUTHERN
THIRD OF THE FORECAST AREA...ESPECIALLY IMPACTING SOUTHERN
SWEETWATER COUNTY BY MONDAY MORNING. SNOWFALL WILL INCREASE MONDAY
AFTERNOON AND MONDAY NIGHT...AND IS FAVORABLE TO BECOME HEAVY AT
TIMES. SNOWFALL ACCUMULATIONS OF 4 TO 7 INCHES ARE POSSIBLE BY
TUESDAY EVENING...AND ARE SUPPORTED BY NATIONAL CENTERS. SOME
HIGHER AMOUNTS ARE POSSIBLE SOUTH OF INTERSTATE 80. WITH CONCERNS
RELATING TO THIS SYSTEM MOUNTING...HAVE ISSUED A WINTER STORM WATCH
FOR THE COUNTY. INTERSTATE 80 WILL BE IMPACTED...THOUGH AGAIN...THE
GREATEST AREA OF IMPACT LOOKS TO BE SOUTH OF THE
INTERSTATE...ESPECIALLY ALONG THE WYOMING AND COLORADO BORDER.

AS THIS SYSTEM IS IMPACTING THE SOUTHERN PORTION OF THE FORECAST
AREA... A WAVE OF LOW PRESSURE LOOKS TO SEND A CANADIAN SYSTEM INTO
NORTHERN WYOMING BY LATE MONDAY NIGHT. SNOWFALL WITH THIS SYSTEM
WILL ESPECIALLY IMPACT THE NORTHERN MOUNTAINS...AND WILL CONTINUE TO
BE MONITORED. EVENTUALLY...THE NORTHERN SYSTEM LOOKS TO TAKE OVER
THE SOUTHERN SYSTEM...WITH SNOWFALL SPREADING TO INCLUDE THE VAST
MAJORITY OF THE FORECAST AREA DURING THE VERY EARLY MORNING HOURS OF
TUESDAY. ALL SITUATIONS WILL CONTINUE TO BE MONITORED...THOUGH
REGARDLESS EVEN TO AMOUNTS...EXPECT A RETURN TO COOLER WEATHER WITH
SNOWFALL VERY FAVORABLE OVER THE AREA.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

NORTHWEST FLOW IS EXPECTED TO DOMINATE THE EXTENDED WITH AT LEAST
ONE DISTINCT SHORTWAVE TROUGH AND ASSOCIATED WEAK COLD FRONT SLIDING
ACROSS THE AREA IN THE FRIDAY/FRIDAY NIGHT TIME FRAME. OTHERWISE...A
RELATIVELY DRY NORTHWEST FLOW IS EXPECTED. WILL INTRODUCE SLIGHT
MOUNTAIN POPS FOR THIS SYSTEM FRIDAY/FRIDAY NIGHT...BUT KEPT THE
LOWER ELEVATIONS DRY FOR NOW...AS THIS SYSTEM APPEARS TO HAVE
LIMITED AVAILABLE MOISTURE.  CANNOT RULE OUT ISOLATED MOUNTAIN SNOW
SHOWERS ON OTHER DAYS MAINLY OVER THE NORTHWEST/NORTHERN
MOUNTAINS...BUT PREVIOUS FORECASTS WERE DRY...AND MOISTURE IS NOT
EXCITING...THUS HAVE KEPT THE ONGOING DRY FORECAST.

TEMPERATURES ON WEDNESDAY WILL BE 15 TO 25 DEGREES BELOW
AVERAGE...WITH SOME AREAS SEEING HIGHS ABOUT 30 DEGREES BELOW
AVERAGE. A WARMING TREND WILL OCCUR LATE THIS WEEK WITH MOST AREAS
RETURNING TO SEASONAL LEVELS BY FRIDAY. THE EXCEPTION WILL PROBABLY
BE TYPICAL TRAPPED CENTRAL BASINS WHERE MODELS TEND TO WARM THEM UP
TOO QUICKLY. A WEAK COLD FRONT FRIDAY/FRIDAY NIGHT...MIGHT ACTUALLY
HELP MIX OUT THOSE TRAPPED BASINS.

&&

.AVIATION.../12Z ISSUANCE/

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

VFR TO MVFR CONDITIONS WILL OCCUR THROUGH 18Z WITH AREAS OF LOW
CLOUDS AND FLURRIES TO LIGHT SNOW. EXPECT SOME MOUNTAIN OBSCURATION
UNTIL 18Z AS WELL. VFR CONDITIONS WILL PREVAIL BY 21Z AND THEN
THROUGH 12Z MONDAY.

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

OVER THE SOUTH UNTIL 15Z VFR TO MVFR CONDITIONS WILL OCCUR DUE TO
LOWER CLOUDS AND AREAS OF LIGHT SNOW. LOW CLOUDS WILL LINGER IN SOME
AREAS UNTIL 19Z. AFTER 22Z VFR CONDITIONS WILL PREVAIL OVER THE
REGION THROUGH 12Z MONDAY.

KPNA...KBPI AND KJAC AIRPORTS WILL SEE VFR CONDITIONS PREVAIL THROUGH
THE FORECAST PERIOD.

&&

.FIRE WEATHER...

ANOTHER RETURN TO WINTER EXPECTED OVER THE NEXT FEW DAYS. GENERALLY
DRY CONDITIONS ANTICIPATED TODAY...WITH MORNING INVERSIONS AND
RELATED PATCHY FOG POSSIBLE. A WINTRY SYSTEM WILL THEN MOVE INTO
SOUTHERN WYOMING MONDAY MORNING...SPREADING SNOWFALL ACROSS
SWEETWATER COUNTY. ANOTHER SYSTEM WILL THEN MOVE INTO NORTHERN
WYOMING MONDAY NIGHT SPREADING SNOWFALL ACROSS THE NORTHERN THIRD OF
THE FORECAST AREA. THESE TWO SYSTEM ARE EXPECTED TO JOIN DURING THE
VERY EARLY MORNING OF TUESDAY...WITH WIDESPREAD SNOWFALL
ANTICIPATED. IT APPEARS AS THOUGH THE GREATEST SNOWFALL AMOUNTS MAY
FALL OVER SOUTHERN WYOMING...WITH A WINTER STORM WATCH ISSUED FOR
THE AREA. STAY TUNED FOR UPDATES TO THIS UPCOMING STORM SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
WYZ028>030.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...AR
FIRE WEATHER...BRANHAM







000
FXUS65 KRIW 010911
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
211 AM MST SUN MAR 1 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

AN INTERESTING FORECAST PERIOD ACROSS WESTERN AND CENTRAL WYOMING. A
FAIRLY QUIET BEGINNING AS LINGER ACTIVITY OTHER SOUTHERN WYOMING
TAPERS OFF THIS MORNING. MORNING INVERSIONS WILL DEVELOP...WITH
PATCHY FOG POSSIBLE ACROSS MUCH OF THE LOW LYING AREAS.

A BRIEF PERIOD OF DRY CONDITIONS ANTICIPATED THROUGH THE OVERNIGHT
HOURS. WHILE THE DRY PERIOD IS ONGOING...AN AREA OF LOW PRESSURE
WILL MOVE SOUTH ALONG THE PACIFIC COASTLINE...FINALLY HEADING INLAND
TOWARDS THE FOUR CORNERS REGION LATE TONIGHT AND INTO MONDAY. AS
THIS SYSTEM PROGRESSES IT WILL SEND SNOWFALL ACROSS THE SOUTHERN
THIRD OF THE FORECAST AREA...ESPECIALLY IMPACTING SOUTHERN
SWEETWATER COUNTY BY MONDAY MORNING. SNOWFALL WILL INCREASE MONDAY
AFTERNOON AND MONDAY NIGHT...AND IS FAVORABLE TO BECOME HEAVY AT
TIMES. SNOWFALL ACCUMULATIONS OF 4 TO 7 INCHES ARE POSSIBLE BY
TUESDAY EVENING...AND ARE SUPPORTED BY NATIONAL CENTERS. SOME
HIGHER AMOUNTS ARE POSSIBLE SOUTH OF INTERSTATE 80. WITH CONCERNS
RELATING TO THIS SYSTEM MOUNTING...HAVE ISSUED A WINTER STORM WATCH
FOR THE COUNTY. INTERSTATE 80 WILL BE IMPACTED...THOUGH AGAIN...THE
GREATEST AREA OF IMPACT LOOKS TO BE SOUTH OF THE
INTERSTATE...ESPECIALLY ALONG THE WYOMING AND COLORADO BORDER.

AS THIS SYSTEM IS IMPACTING THE SOUTHERN PORTION OF THE FORECAST
AREA... A WAVE OF LOW PRESSURE LOOKS TO SEND A CANADIAN SYSTEM INTO
NORTHERN WYOMING BY LATE MONDAY NIGHT. SNOWFALL WITH THIS SYSTEM
WILL ESPECIALLY IMPACT THE NORTHERN MOUNTAINS...AND WILL CONTINUE TO
BE MONITORED. EVENTUALLY...THE NORTHERN SYSTEM LOOKS TO TAKE OVER
THE SOUTHERN SYSTEM...WITH SNOWFALL SPREADING TO INCLUDE THE VAST
MAJORITY OF THE FORECAST AREA DURING THE VERY EARLY MORNING HOURS OF
TUESDAY. ALL SITUATIONS WILL CONTINUE TO BE MONITORED...THOUGH
REGARDLESS EVEN TO AMOUNTS...EXPECT A RETURN TO COOLER WEATHER WITH
SNOWFALL VERY FAVORABLE OVER THE AREA.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

NORTHWEST FLOW IS EXPECTED TO DOMINATE THE EXTENDED WITH AT LEAST
ONE DISTINCT SHORTWAVE TROUGH AND ASSOCIATED WEAK COLD FRONT SLIDING
ACROSS THE AREA IN THE FRIDAY/FRIDAY NIGHT TIME FRAME. OTHERWISE...A
RELATIVELY DRY NORTHWEST FLOW IS EXPECTED. WILL INTRODUCE SLIGHT
MOUNTAIN POPS FOR THIS SYSTEM FRIDAY/FRIDAY NIGHT...BUT KEPT THE
LOWER ELEVATIONS DRY FOR NOW...AS THIS SYSTEM APPEARS TO HAVE
LIMITED AVAILABLE MOISTURE.  CANNOT RULE OUT ISOLATED MOUNTAIN SNOW
SHOWERS ON OTHER DAYS MAINLY OVER THE NORTHWEST/NORTHERN
MOUNTAINS...BUT PREVIOUS FORECASTS WERE DRY...AND MOISTURE IS NOT
EXCITING...THUS HAVE KEPT THE ONGOING DRY FORECAST.

TEMPERATURES ON WEDNESDAY WILL BE 15 TO 25 DEGREES BELOW
AVERAGE...WITH SOME AREAS SEEING HIGHS ABOUT 30 DEGREES BELOW
AVERAGE. A WARMING TREND WILL OCCUR LATE THIS WEEK WITH MOST AREAS
RETURNING TO SEASONAL LEVELS BY FRIDAY. THE EXCEPTION WILL PROBABLY
BE TYPICAL TRAPPED CENTRAL BASINS WHERE MODELS TEND TO WARM THEM UP
TOO QUICKLY. A WEAK COLD FRONT FRIDAY/FRIDAY NIGHT...MIGHT ACTUALLY
HELP MIX OUT THOSE TRAPPED BASINS.

&&

.AVIATION.../12Z ISSUANCE/

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

VFR TO MVFR CONDITIONS WILL OCCUR THROUGH 18Z WITH AREAS OF LOW
CLOUDS AND FLURRIES TO LIGHT SNOW. EXPECT SOME MOUNTAIN OBSCURATION
UNTIL 18Z AS WELL. VFR CONDITIONS WILL PREVAIL BY 21Z AND THEN
THROUGH 12Z MONDAY.

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

OVER THE SOUTH UNTIL 15Z VFR TO MVFR CONDITIONS WILL OCCUR DUE TO
LOWER CLOUDS AND AREAS OF LIGHT SNOW. LOW CLOUDS WILL LINGER IN SOME
AREAS UNTIL 19Z. AFTER 22Z VFR CONDITIONS WILL PREVAIL OVER THE
REGION THROUGH 12Z MONDAY.

KPNA...KBPI AND KJAC AIRPORTS WILL SEE VFR CONDITIONS PREVAIL THROUGH
THE FORECAST PERIOD.

&&

.FIRE WEATHER...

ANOTHER RETURN TO WINTER EXPECTED OVER THE NEXT FEW DAYS. GENERALLY
DRY CONDITIONS ANTICIPATED TODAY...WITH MORNING INVERSIONS AND
RELATED PATCHY FOG POSSIBLE. A WINTRY SYSTEM WILL THEN MOVE INTO
SOUTHERN WYOMING MONDAY MORNING...SPREADING SNOWFALL ACROSS
SWEETWATER COUNTY. ANOTHER SYSTEM WILL THEN MOVE INTO NORTHERN
WYOMING MONDAY NIGHT SPREADING SNOWFALL ACROSS THE NORTHERN THIRD OF
THE FORECAST AREA. THESE TWO SYSTEM ARE EXPECTED TO JOIN DURING THE
VERY EARLY MORNING OF TUESDAY...WITH WIDESPREAD SNOWFALL
ANTICIPATED. IT APPEARS AS THOUGH THE GREATEST SNOWFALL AMOUNTS MAY
FALL OVER SOUTHERN WYOMING...WITH A WINTER STORM WATCH ISSUED FOR
THE AREA. STAY TUNED FOR UPDATES TO THIS UPCOMING STORM SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
WYZ028>030.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...AR
FIRE WEATHER...BRANHAM







000
FXUS65 KRIW 010911
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
211 AM MST SUN MAR 1 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

AN INTERESTING FORECAST PERIOD ACROSS WESTERN AND CENTRAL WYOMING. A
FAIRLY QUIET BEGINNING AS LINGER ACTIVITY OTHER SOUTHERN WYOMING
TAPERS OFF THIS MORNING. MORNING INVERSIONS WILL DEVELOP...WITH
PATCHY FOG POSSIBLE ACROSS MUCH OF THE LOW LYING AREAS.

A BRIEF PERIOD OF DRY CONDITIONS ANTICIPATED THROUGH THE OVERNIGHT
HOURS. WHILE THE DRY PERIOD IS ONGOING...AN AREA OF LOW PRESSURE
WILL MOVE SOUTH ALONG THE PACIFIC COASTLINE...FINALLY HEADING INLAND
TOWARDS THE FOUR CORNERS REGION LATE TONIGHT AND INTO MONDAY. AS
THIS SYSTEM PROGRESSES IT WILL SEND SNOWFALL ACROSS THE SOUTHERN
THIRD OF THE FORECAST AREA...ESPECIALLY IMPACTING SOUTHERN
SWEETWATER COUNTY BY MONDAY MORNING. SNOWFALL WILL INCREASE MONDAY
AFTERNOON AND MONDAY NIGHT...AND IS FAVORABLE TO BECOME HEAVY AT
TIMES. SNOWFALL ACCUMULATIONS OF 4 TO 7 INCHES ARE POSSIBLE BY
TUESDAY EVENING...AND ARE SUPPORTED BY NATIONAL CENTERS. SOME
HIGHER AMOUNTS ARE POSSIBLE SOUTH OF INTERSTATE 80. WITH CONCERNS
RELATING TO THIS SYSTEM MOUNTING...HAVE ISSUED A WINTER STORM WATCH
FOR THE COUNTY. INTERSTATE 80 WILL BE IMPACTED...THOUGH AGAIN...THE
GREATEST AREA OF IMPACT LOOKS TO BE SOUTH OF THE
INTERSTATE...ESPECIALLY ALONG THE WYOMING AND COLORADO BORDER.

AS THIS SYSTEM IS IMPACTING THE SOUTHERN PORTION OF THE FORECAST
AREA... A WAVE OF LOW PRESSURE LOOKS TO SEND A CANADIAN SYSTEM INTO
NORTHERN WYOMING BY LATE MONDAY NIGHT. SNOWFALL WITH THIS SYSTEM
WILL ESPECIALLY IMPACT THE NORTHERN MOUNTAINS...AND WILL CONTINUE TO
BE MONITORED. EVENTUALLY...THE NORTHERN SYSTEM LOOKS TO TAKE OVER
THE SOUTHERN SYSTEM...WITH SNOWFALL SPREADING TO INCLUDE THE VAST
MAJORITY OF THE FORECAST AREA DURING THE VERY EARLY MORNING HOURS OF
TUESDAY. ALL SITUATIONS WILL CONTINUE TO BE MONITORED...THOUGH
REGARDLESS EVEN TO AMOUNTS...EXPECT A RETURN TO COOLER WEATHER WITH
SNOWFALL VERY FAVORABLE OVER THE AREA.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

NORTHWEST FLOW IS EXPECTED TO DOMINATE THE EXTENDED WITH AT LEAST
ONE DISTINCT SHORTWAVE TROUGH AND ASSOCIATED WEAK COLD FRONT SLIDING
ACROSS THE AREA IN THE FRIDAY/FRIDAY NIGHT TIME FRAME. OTHERWISE...A
RELATIVELY DRY NORTHWEST FLOW IS EXPECTED. WILL INTRODUCE SLIGHT
MOUNTAIN POPS FOR THIS SYSTEM FRIDAY/FRIDAY NIGHT...BUT KEPT THE
LOWER ELEVATIONS DRY FOR NOW...AS THIS SYSTEM APPEARS TO HAVE
LIMITED AVAILABLE MOISTURE.  CANNOT RULE OUT ISOLATED MOUNTAIN SNOW
SHOWERS ON OTHER DAYS MAINLY OVER THE NORTHWEST/NORTHERN
MOUNTAINS...BUT PREVIOUS FORECASTS WERE DRY...AND MOISTURE IS NOT
EXCITING...THUS HAVE KEPT THE ONGOING DRY FORECAST.

TEMPERATURES ON WEDNESDAY WILL BE 15 TO 25 DEGREES BELOW
AVERAGE...WITH SOME AREAS SEEING HIGHS ABOUT 30 DEGREES BELOW
AVERAGE. A WARMING TREND WILL OCCUR LATE THIS WEEK WITH MOST AREAS
RETURNING TO SEASONAL LEVELS BY FRIDAY. THE EXCEPTION WILL PROBABLY
BE TYPICAL TRAPPED CENTRAL BASINS WHERE MODELS TEND TO WARM THEM UP
TOO QUICKLY. A WEAK COLD FRONT FRIDAY/FRIDAY NIGHT...MIGHT ACTUALLY
HELP MIX OUT THOSE TRAPPED BASINS.

&&

.AVIATION.../12Z ISSUANCE/

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

VFR TO MVFR CONDITIONS WILL OCCUR THROUGH 18Z WITH AREAS OF LOW
CLOUDS AND FLURRIES TO LIGHT SNOW. EXPECT SOME MOUNTAIN OBSCURATION
UNTIL 18Z AS WELL. VFR CONDITIONS WILL PREVAIL BY 21Z AND THEN
THROUGH 12Z MONDAY.

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

OVER THE SOUTH UNTIL 15Z VFR TO MVFR CONDITIONS WILL OCCUR DUE TO
LOWER CLOUDS AND AREAS OF LIGHT SNOW. LOW CLOUDS WILL LINGER IN SOME
AREAS UNTIL 19Z. AFTER 22Z VFR CONDITIONS WILL PREVAIL OVER THE
REGION THROUGH 12Z MONDAY.

KPNA...KBPI AND KJAC AIRPORTS WILL SEE VFR CONDITIONS PREVAIL THROUGH
THE FORECAST PERIOD.

&&

.FIRE WEATHER...

ANOTHER RETURN TO WINTER EXPECTED OVER THE NEXT FEW DAYS. GENERALLY
DRY CONDITIONS ANTICIPATED TODAY...WITH MORNING INVERSIONS AND
RELATED PATCHY FOG POSSIBLE. A WINTRY SYSTEM WILL THEN MOVE INTO
SOUTHERN WYOMING MONDAY MORNING...SPREADING SNOWFALL ACROSS
SWEETWATER COUNTY. ANOTHER SYSTEM WILL THEN MOVE INTO NORTHERN
WYOMING MONDAY NIGHT SPREADING SNOWFALL ACROSS THE NORTHERN THIRD OF
THE FORECAST AREA. THESE TWO SYSTEM ARE EXPECTED TO JOIN DURING THE
VERY EARLY MORNING OF TUESDAY...WITH WIDESPREAD SNOWFALL
ANTICIPATED. IT APPEARS AS THOUGH THE GREATEST SNOWFALL AMOUNTS MAY
FALL OVER SOUTHERN WYOMING...WITH A WINTER STORM WATCH ISSUED FOR
THE AREA. STAY TUNED FOR UPDATES TO THIS UPCOMING STORM SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
WYZ028>030.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...AR
FIRE WEATHER...BRANHAM








000
FXUS65 KRIW 010911
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
211 AM MST SUN MAR 1 2015

.SHORT TERM...TODAY THROUGH TUESDAY NIGHT

AN INTERESTING FORECAST PERIOD ACROSS WESTERN AND CENTRAL WYOMING. A
FAIRLY QUIET BEGINNING AS LINGER ACTIVITY OTHER SOUTHERN WYOMING
TAPERS OFF THIS MORNING. MORNING INVERSIONS WILL DEVELOP...WITH
PATCHY FOG POSSIBLE ACROSS MUCH OF THE LOW LYING AREAS.

A BRIEF PERIOD OF DRY CONDITIONS ANTICIPATED THROUGH THE OVERNIGHT
HOURS. WHILE THE DRY PERIOD IS ONGOING...AN AREA OF LOW PRESSURE
WILL MOVE SOUTH ALONG THE PACIFIC COASTLINE...FINALLY HEADING INLAND
TOWARDS THE FOUR CORNERS REGION LATE TONIGHT AND INTO MONDAY. AS
THIS SYSTEM PROGRESSES IT WILL SEND SNOWFALL ACROSS THE SOUTHERN
THIRD OF THE FORECAST AREA...ESPECIALLY IMPACTING SOUTHERN
SWEETWATER COUNTY BY MONDAY MORNING. SNOWFALL WILL INCREASE MONDAY
AFTERNOON AND MONDAY NIGHT...AND IS FAVORABLE TO BECOME HEAVY AT
TIMES. SNOWFALL ACCUMULATIONS OF 4 TO 7 INCHES ARE POSSIBLE BY
TUESDAY EVENING...AND ARE SUPPORTED BY NATIONAL CENTERS. SOME
HIGHER AMOUNTS ARE POSSIBLE SOUTH OF INTERSTATE 80. WITH CONCERNS
RELATING TO THIS SYSTEM MOUNTING...HAVE ISSUED A WINTER STORM WATCH
FOR THE COUNTY. INTERSTATE 80 WILL BE IMPACTED...THOUGH AGAIN...THE
GREATEST AREA OF IMPACT LOOKS TO BE SOUTH OF THE
INTERSTATE...ESPECIALLY ALONG THE WYOMING AND COLORADO BORDER.

AS THIS SYSTEM IS IMPACTING THE SOUTHERN PORTION OF THE FORECAST
AREA... A WAVE OF LOW PRESSURE LOOKS TO SEND A CANADIAN SYSTEM INTO
NORTHERN WYOMING BY LATE MONDAY NIGHT. SNOWFALL WITH THIS SYSTEM
WILL ESPECIALLY IMPACT THE NORTHERN MOUNTAINS...AND WILL CONTINUE TO
BE MONITORED. EVENTUALLY...THE NORTHERN SYSTEM LOOKS TO TAKE OVER
THE SOUTHERN SYSTEM...WITH SNOWFALL SPREADING TO INCLUDE THE VAST
MAJORITY OF THE FORECAST AREA DURING THE VERY EARLY MORNING HOURS OF
TUESDAY. ALL SITUATIONS WILL CONTINUE TO BE MONITORED...THOUGH
REGARDLESS EVEN TO AMOUNTS...EXPECT A RETURN TO COOLER WEATHER WITH
SNOWFALL VERY FAVORABLE OVER THE AREA.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

NORTHWEST FLOW IS EXPECTED TO DOMINATE THE EXTENDED WITH AT LEAST
ONE DISTINCT SHORTWAVE TROUGH AND ASSOCIATED WEAK COLD FRONT SLIDING
ACROSS THE AREA IN THE FRIDAY/FRIDAY NIGHT TIME FRAME. OTHERWISE...A
RELATIVELY DRY NORTHWEST FLOW IS EXPECTED. WILL INTRODUCE SLIGHT
MOUNTAIN POPS FOR THIS SYSTEM FRIDAY/FRIDAY NIGHT...BUT KEPT THE
LOWER ELEVATIONS DRY FOR NOW...AS THIS SYSTEM APPEARS TO HAVE
LIMITED AVAILABLE MOISTURE.  CANNOT RULE OUT ISOLATED MOUNTAIN SNOW
SHOWERS ON OTHER DAYS MAINLY OVER THE NORTHWEST/NORTHERN
MOUNTAINS...BUT PREVIOUS FORECASTS WERE DRY...AND MOISTURE IS NOT
EXCITING...THUS HAVE KEPT THE ONGOING DRY FORECAST.

TEMPERATURES ON WEDNESDAY WILL BE 15 TO 25 DEGREES BELOW
AVERAGE...WITH SOME AREAS SEEING HIGHS ABOUT 30 DEGREES BELOW
AVERAGE. A WARMING TREND WILL OCCUR LATE THIS WEEK WITH MOST AREAS
RETURNING TO SEASONAL LEVELS BY FRIDAY. THE EXCEPTION WILL PROBABLY
BE TYPICAL TRAPPED CENTRAL BASINS WHERE MODELS TEND TO WARM THEM UP
TOO QUICKLY. A WEAK COLD FRONT FRIDAY/FRIDAY NIGHT...MIGHT ACTUALLY
HELP MIX OUT THOSE TRAPPED BASINS.

&&

.AVIATION.../12Z ISSUANCE/

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

VFR TO MVFR CONDITIONS WILL OCCUR THROUGH 18Z WITH AREAS OF LOW
CLOUDS AND FLURRIES TO LIGHT SNOW. EXPECT SOME MOUNTAIN OBSCURATION
UNTIL 18Z AS WELL. VFR CONDITIONS WILL PREVAIL BY 21Z AND THEN
THROUGH 12Z MONDAY.

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

OVER THE SOUTH UNTIL 15Z VFR TO MVFR CONDITIONS WILL OCCUR DUE TO
LOWER CLOUDS AND AREAS OF LIGHT SNOW. LOW CLOUDS WILL LINGER IN SOME
AREAS UNTIL 19Z. AFTER 22Z VFR CONDITIONS WILL PREVAIL OVER THE
REGION THROUGH 12Z MONDAY.

KPNA...KBPI AND KJAC AIRPORTS WILL SEE VFR CONDITIONS PREVAIL THROUGH
THE FORECAST PERIOD.

&&

.FIRE WEATHER...

ANOTHER RETURN TO WINTER EXPECTED OVER THE NEXT FEW DAYS. GENERALLY
DRY CONDITIONS ANTICIPATED TODAY...WITH MORNING INVERSIONS AND
RELATED PATCHY FOG POSSIBLE. A WINTRY SYSTEM WILL THEN MOVE INTO
SOUTHERN WYOMING MONDAY MORNING...SPREADING SNOWFALL ACROSS
SWEETWATER COUNTY. ANOTHER SYSTEM WILL THEN MOVE INTO NORTHERN
WYOMING MONDAY NIGHT SPREADING SNOWFALL ACROSS THE NORTHERN THIRD OF
THE FORECAST AREA. THESE TWO SYSTEM ARE EXPECTED TO JOIN DURING THE
VERY EARLY MORNING OF TUESDAY...WITH WIDESPREAD SNOWFALL
ANTICIPATED. IT APPEARS AS THOUGH THE GREATEST SNOWFALL AMOUNTS MAY
FALL OVER SOUTHERN WYOMING...WITH A WINTER STORM WATCH ISSUED FOR
THE AREA. STAY TUNED FOR UPDATES TO THIS UPCOMING STORM SYSTEM.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM LATE TONIGHT THROUGH TUESDAY AFTERNOON
WYZ028>030.

&&

$$

SHORT TERM...BRANHAM
LONG TERM...WM
AVIATION...AR
FIRE WEATHER...BRANHAM







000
FXUS65 KRIW 010502
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1002 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 253 PM MST)

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../06Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z SUNDAY
WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE WIDESPREAD
MOUNTAIN OBSCURATIONS THROUGH 18Z SUNDAY. SOME CLEARING WILL OCCUR
OVER THE REGION AFTER 18Z WITH VFR CONDITIONS PREVAILING BY 21Z.

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

WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL FOG OVER THE
SOUTH THROUGH 12Z WITH IFR TO MVFR CONDITIONS. CONDITIONS WILL
IMPROVE AFTER 19Z WITH VFR CONDITIONS PREVAILING BY 22Z.

THE REST OF THE REGION WILL HAVE VFR CEILINGS OVERNIGHT INTO SUNDAY
MORNING. CLOUDS WILL DECREASE AROUND 18Z SUNDAY BUT THEN INCREASE
AGAIN SUNDAY NIGHT WITH VFR CEILINGS BY 03Z MONDAY.

KJAC AIRPORT WILL SEE VFR CONDITIONS PREVAIL THROUGH THE FORECAST
PERIOD.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

&&

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...AR
FIRE WEATHER...C.BAKER












000
FXUS65 KRIW 010502
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1002 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 253 PM MST)

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../06Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z SUNDAY
WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE WIDESPREAD
MOUNTAIN OBSCURATIONS THROUGH 18Z SUNDAY. SOME CLEARING WILL OCCUR
OVER THE REGION AFTER 18Z WITH VFR CONDITIONS PREVAILING BY 21Z.

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

WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL FOG OVER THE
SOUTH THROUGH 12Z WITH IFR TO MVFR CONDITIONS. CONDITIONS WILL
IMPROVE AFTER 19Z WITH VFR CONDITIONS PREVAILING BY 22Z.

THE REST OF THE REGION WILL HAVE VFR CEILINGS OVERNIGHT INTO SUNDAY
MORNING. CLOUDS WILL DECREASE AROUND 18Z SUNDAY BUT THEN INCREASE
AGAIN SUNDAY NIGHT WITH VFR CEILINGS BY 03Z MONDAY.

KJAC AIRPORT WILL SEE VFR CONDITIONS PREVAIL THROUGH THE FORECAST
PERIOD.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

&&

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...AR
FIRE WEATHER...C.BAKER












000
FXUS65 KRIW 010502
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1002 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 253 PM MST)

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../06Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z SUNDAY
WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE WIDESPREAD
MOUNTAIN OBSCURATIONS THROUGH 18Z SUNDAY. SOME CLEARING WILL OCCUR
OVER THE REGION AFTER 18Z WITH VFR CONDITIONS PREVAILING BY 21Z.

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

WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL FOG OVER THE
SOUTH THROUGH 12Z WITH IFR TO MVFR CONDITIONS. CONDITIONS WILL
IMPROVE AFTER 19Z WITH VFR CONDITIONS PREVAILING BY 22Z.

THE REST OF THE REGION WILL HAVE VFR CEILINGS OVERNIGHT INTO SUNDAY
MORNING. CLOUDS WILL DECREASE AROUND 18Z SUNDAY BUT THEN INCREASE
AGAIN SUNDAY NIGHT WITH VFR CEILINGS BY 03Z MONDAY.

KJAC AIRPORT WILL SEE VFR CONDITIONS PREVAIL THROUGH THE FORECAST
PERIOD.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

&&

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...AR
FIRE WEATHER...C.BAKER












000
FXUS65 KRIW 010502
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1002 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 253 PM MST)

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../06Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z SUNDAY
WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE WIDESPREAD
MOUNTAIN OBSCURATIONS THROUGH 18Z SUNDAY. SOME CLEARING WILL OCCUR
OVER THE REGION AFTER 18Z WITH VFR CONDITIONS PREVAILING BY 21Z.

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

WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL FOG OVER THE
SOUTH THROUGH 12Z WITH IFR TO MVFR CONDITIONS. CONDITIONS WILL
IMPROVE AFTER 19Z WITH VFR CONDITIONS PREVAILING BY 22Z.

THE REST OF THE REGION WILL HAVE VFR CEILINGS OVERNIGHT INTO SUNDAY
MORNING. CLOUDS WILL DECREASE AROUND 18Z SUNDAY BUT THEN INCREASE
AGAIN SUNDAY NIGHT WITH VFR CEILINGS BY 03Z MONDAY.

KJAC AIRPORT WILL SEE VFR CONDITIONS PREVAIL THROUGH THE FORECAST
PERIOD.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

&&

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...AR
FIRE WEATHER...C.BAKER












000
FXUS65 KRIW 010502
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1002 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 253 PM MST)

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../06Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z SUNDAY
WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE WIDESPREAD
MOUNTAIN OBSCURATIONS THROUGH 18Z SUNDAY. SOME CLEARING WILL OCCUR
OVER THE REGION AFTER 18Z WITH VFR CONDITIONS PREVAILING BY 21Z.

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

WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL FOG OVER THE
SOUTH THROUGH 12Z WITH IFR TO MVFR CONDITIONS. CONDITIONS WILL
IMPROVE AFTER 19Z WITH VFR CONDITIONS PREVAILING BY 22Z.

THE REST OF THE REGION WILL HAVE VFR CEILINGS OVERNIGHT INTO SUNDAY
MORNING. CLOUDS WILL DECREASE AROUND 18Z SUNDAY BUT THEN INCREASE
AGAIN SUNDAY NIGHT WITH VFR CEILINGS BY 03Z MONDAY.

KJAC AIRPORT WILL SEE VFR CONDITIONS PREVAIL THROUGH THE FORECAST
PERIOD.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

&&

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...AR
FIRE WEATHER...C.BAKER











000
FXUS65 KRIW 010502
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1002 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 253 PM MST)

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../06Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z SUNDAY
WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE WIDESPREAD
MOUNTAIN OBSCURATIONS THROUGH 18Z SUNDAY. SOME CLEARING WILL OCCUR
OVER THE REGION AFTER 18Z WITH VFR CONDITIONS PREVAILING BY 21Z.

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

WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL FOG OVER THE
SOUTH THROUGH 12Z WITH IFR TO MVFR CONDITIONS. CONDITIONS WILL
IMPROVE AFTER 19Z WITH VFR CONDITIONS PREVAILING BY 22Z.

THE REST OF THE REGION WILL HAVE VFR CEILINGS OVERNIGHT INTO SUNDAY
MORNING. CLOUDS WILL DECREASE AROUND 18Z SUNDAY BUT THEN INCREASE
AGAIN SUNDAY NIGHT WITH VFR CEILINGS BY 03Z MONDAY.

KJAC AIRPORT WILL SEE VFR CONDITIONS PREVAIL THROUGH THE FORECAST
PERIOD.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

&&

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...AR
FIRE WEATHER...C.BAKER











000
FXUS65 KRIW 010502
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1002 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 253 PM MST)

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../06Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z SUNDAY
WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE WIDESPREAD
MOUNTAIN OBSCURATIONS THROUGH 18Z SUNDAY. SOME CLEARING WILL OCCUR
OVER THE REGION AFTER 18Z WITH VFR CONDITIONS PREVAILING BY 21Z.

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

WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL FOG OVER THE
SOUTH THROUGH 12Z WITH IFR TO MVFR CONDITIONS. CONDITIONS WILL
IMPROVE AFTER 19Z WITH VFR CONDITIONS PREVAILING BY 22Z.

THE REST OF THE REGION WILL HAVE VFR CEILINGS OVERNIGHT INTO SUNDAY
MORNING. CLOUDS WILL DECREASE AROUND 18Z SUNDAY BUT THEN INCREASE
AGAIN SUNDAY NIGHT WITH VFR CEILINGS BY 03Z MONDAY.

KJAC AIRPORT WILL SEE VFR CONDITIONS PREVAIL THROUGH THE FORECAST
PERIOD.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

&&

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...AR
FIRE WEATHER...C.BAKER











000
FXUS65 KRIW 010502
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1002 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY (ISSUED AT 253 PM MST)

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../06Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z SUNDAY
WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE WIDESPREAD
MOUNTAIN OBSCURATIONS THROUGH 18Z SUNDAY. SOME CLEARING WILL OCCUR
OVER THE REGION AFTER 18Z WITH VFR CONDITIONS PREVAILING BY 21Z.

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

WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL FOG OVER THE
SOUTH THROUGH 12Z WITH IFR TO MVFR CONDITIONS. CONDITIONS WILL
IMPROVE AFTER 19Z WITH VFR CONDITIONS PREVAILING BY 22Z.

THE REST OF THE REGION WILL HAVE VFR CEILINGS OVERNIGHT INTO SUNDAY
MORNING. CLOUDS WILL DECREASE AROUND 18Z SUNDAY BUT THEN INCREASE
AGAIN SUNDAY NIGHT WITH VFR CEILINGS BY 03Z MONDAY.

KJAC AIRPORT WILL SEE VFR CONDITIONS PREVAIL THROUGH THE FORECAST
PERIOD.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

&&

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...AR
FIRE WEATHER...C.BAKER











000
FXUS65 KCYS 010500
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1000 PM MST SAT FEB 28 2015

.UPDATE...
ISSUED AT 952 PM MST SAT FEB 28 2015

LOOKING AT RADAR MOSAIC...SNOW IS REALLY HAVING A TOUGH TIME
GETTING OVER THE SOUTH LARAMIE RANGE THIS EVENING. GETTING SOME
SNOW WEST OF THE LARAMIE RANGE...BUT NOTHING SO FAR TO THE EAST.
WENT AHEAD AND LOWERED POPS SOME FOR THE OVERNIGHT HOURS. UPDATES
HAVE BEEN SENT.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 340 PM MST SAT FEB 28 2015

A FEW SNOW FLURRIES WILL LINGER ALONG THE EASTERN FRINGES OF THE
SOUTHERN LARAMIE RANGE THROUGH THIS AFTERNOON. THE MAIN CHANCES
FOR ACCUMULATING SNOW WILL OCCUR THIS EVENING AND INTO THE
OVERNIGHT AS SUBTLE SHORTWAVE FEATURES MOVE INTO SOUTHEAST WYOMING
FROM COLORADO...AND ELEVATED WARM ADVECTION DEVELOPS. THE BEST
CHANCES FOR SNOW ACCUMULATIONS OUTSIDE OF THE MOUNTAINS WILL BE
ALONG AND NEAR THE COLORADO BORDER BUT EVEN THERE ANY
ACCUMULATIONS WILL BE MINIMAL AND GENERALLY LESS THAN ONE INCH.
KEPT SLIGHT CHANCES GOING INTO EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE...BUT IT IS LOOKING LESS LIKELY THAT
ANY SNOW WILL OCCUR IN THOSE AREAS TONIGHT OR TOMORROW WITH THE
BEST UPPER LEVEL FORCING WELL TO THE SOUTH.

WILL HAVE TO KEEP AN EYE ON HOW THE UPPER LEVELS EVOLVE EARLY NEXT
WEEK. MODELS SHOWING A CUT OFF LOW EJECTING NORTHEASTWARD OUT OF
CALIFORNIA AS A KICKER DROPS SOUTH OFF THE PACIFIC NORTHWEST
COAST. ECMWF INITIALLY KEEPS MUCH OF THE ENERGY OVER SOUTHCENTRAL
WYOMING MONDAY INTO MONDAY NIGHT AND THEN QUICKLY PUSHES THINGS
EASTWARD. THE GFS BRINGS THE MAIN ENERGY OVER FAR SOUTHEAST
WYOMING AND PRODUCES HIGHER AMOUNTS OF PRECIPITATION THERE. NOT
CONFIDENT IN EITHER SOLUTION AND SOMEWHAT SURPRISED HOW MUCH
PRECIPITATION THE MODELS ARE PRODUCING GIVEN THE PLACEMENT OF THE
UPPER LEVEL JET.

DEPENDING ON THE NEXT ROUND OF MODEL RUNS...MAY NEED WINTER WEATHER
HEADLINES FOR SOUTHCENTRAL WYOMING MONDAY THROUGH MONDAY NIGHT.
LIGHT SNOW COULD START FALLING IN THAT AREA LATE SUNDAY NIGHT BUT
AT THIS TIME IT APPEARS A MAJORITY OF THE SNOW WILL FALL AFTER 12Z
MONDAY THROUGH MONDAY NIGHT ACROSS THIS AREA.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 315 PM MST SAT FEB 28 2015

MAIN FORECAST CONCERN IN THE MEDIUM RANGE WILL BE THE CONTINUING
WINTER WEATHER EVENT ON TUESDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT WITH THIS STORM SYSTEM...SHOWING A SECONDARY SHORTWAVE
ALOFT DIGGING SOUTHWARD...WHICH WILL BE ASSOCIATED WITH THE
ARCTIC AIRMASS MOVING INTO WYOMING EARLY TUESDAY MORNING. HIGH
TEMPERATURES ON TUESDAY WILL LIKELY BE SIMILAR TO THE LOW
TEMPERATURES MONDAY NIGHT...AND GENERALLY IN THE TEENS TO LOW 20S.
TEMPERATURES WILL LOWER INTO THE SINGLE DIGITS AND LOW TEENS
THROUGH THE AFTERNOON AS THE 1035MB ARCTIC HIGH AT THE SURFACE
MOVES INTO THE AREA. KEPT A 60 PCT TO 80 PCT CHANCE OF SNOW FOR
MOST OF SOUTHEAST WYOMING INTO TUESDAY EVENING FOR AN ADDITIONAL 1
TO 3 INCHES OF SNOW ACCUMULATION. LOW TEMPERATURES TUESDAY NIGHT
WILL BE TRICKY AND WILL GREATLY DEPEND ON THE EXTENT OF SURFACE
SNOW COVER...DEPTH...AND IF SKIES CLEAR OUT OR NOT. CONSIDERING HOW
PROGRESSIVE THE SYSTEM IS AS INDICATED BY MODELS...BELIEVE MOST OF
THE FORECAST AREA AND ESPECIALLY NORTH OF I80...WILL HAVE CLEARING
SKIES OVERNIGHT. LOW TEMPERATURES MAY APPROACH -15 TO -20 IN THE
MORE SHELTERED VALLEYS ACROSS SOUTHEAST WYOMING WITH THE CENTER OF
THE ARCTIC HIGH JUST EAST OF THE LARAMIE RANGE.
ELSEWHERE...TEMPERATURES BETWEEN -5 TO -10 APPEAR LIKELY AT THIS
TIME IF BROKEN TO OVERCAST CONDITIONS CONTINUE THROUGH MOST OF THE
NIGHT.

WEDNESDAY THROUGH THE END OF THE WEEK...SOME FLURRIES ARE POSSIBLE
AS THE STORM SYSTEM EXITS THE REGION TO OUR SOUTH. WEDNESDAY WILL
BE THE COLDEST DAY OF THE WEEK WITH HIGHS STRUGGLING TO REACH THE
LOW TO MID TEENS. KEPT HIGHS A FEW DEGREES ABOVE MOS...BUT GAMBLING
THAT THE WESTERLY WINDS AND MARCH SUNSHINE WILL RESULT IN
TEMPERATURES A FEW DEGREES HIGHER THAN GUIDANCE.
OTHERWISE...TEMPERATURES MAY BE STUCK IN THE SINGLE DIGITS THROUGH
THE AFTERNOON. EITHER WAY...A WARMING TREND IS EXPECTED FOR THE
REMAINDER OF THE WEEK AS THE STRONG EASTERN PACIFIC RIDGE EXPANDS
EASTWARD A BIT INTO THE CENTRAL AND SOUTHERN ROCKY MOUNTAINS. DUE
TO POTENTIAL SNOW COVER...DID KEEP TEMPERATURES LOWER THAN MOS
THROUGH THE WEEK...WITH TEMPERATURES ABOVE GUIDANCE BY NEXT
WEEKEND AS MOST OF THE SNOW SHOULD MELT BY THAT TIME. EXPECT HIGHS
TO RETURN TO THE 40S TO AROUND 50 BY FRIDAY AND SATURDAY
AFTERNOON.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 952 PM MST SAT FEB 28 2015

TOUGH FORECAST FOR OUR SOUTHEAST WYOMING AIRPORTS. RADAR SHOWING
AREA OF SNOW FILLING IN FROM KCYS TO KLAR...BUT IT IS NOT TOO
HEAVY AND BARELY RESTRICTING VISIBILITIES. GOING TO HOLD OFF
ONLOWERING CONDITIONS UNTIL AFTER 12Z AND CONFINE LOWER CONDITIONS
TO KLAR.

&&

.FIRE WEATHER...

ISSUED AT 240 AM MST SAT FEB 28 2015

C0LDER THAN NORMAL TEMPERATURES...AMPLE SURFACE MOISTURE FROM
SNOWFALL...AND HIGH RELATIVE HUMIDITIES WILL PRECLUDE FIRE WEATHER
CONCERNS THROUGH NEXT WEEK.

&&

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

$$

UPDATE...GCC
SHORT TERM...SML
LONG TERM...TJT
AVIATION...GCC
FIRE WEATHER...MAJ



000
FXUS65 KCYS 010500
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1000 PM MST SAT FEB 28 2015

.UPDATE...
ISSUED AT 952 PM MST SAT FEB 28 2015

LOOKING AT RADAR MOSAIC...SNOW IS REALLY HAVING A TOUGH TIME
GETTING OVER THE SOUTH LARAMIE RANGE THIS EVENING. GETTING SOME
SNOW WEST OF THE LARAMIE RANGE...BUT NOTHING SO FAR TO THE EAST.
WENT AHEAD AND LOWERED POPS SOME FOR THE OVERNIGHT HOURS. UPDATES
HAVE BEEN SENT.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 340 PM MST SAT FEB 28 2015

A FEW SNOW FLURRIES WILL LINGER ALONG THE EASTERN FRINGES OF THE
SOUTHERN LARAMIE RANGE THROUGH THIS AFTERNOON. THE MAIN CHANCES
FOR ACCUMULATING SNOW WILL OCCUR THIS EVENING AND INTO THE
OVERNIGHT AS SUBTLE SHORTWAVE FEATURES MOVE INTO SOUTHEAST WYOMING
FROM COLORADO...AND ELEVATED WARM ADVECTION DEVELOPS. THE BEST
CHANCES FOR SNOW ACCUMULATIONS OUTSIDE OF THE MOUNTAINS WILL BE
ALONG AND NEAR THE COLORADO BORDER BUT EVEN THERE ANY
ACCUMULATIONS WILL BE MINIMAL AND GENERALLY LESS THAN ONE INCH.
KEPT SLIGHT CHANCES GOING INTO EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE...BUT IT IS LOOKING LESS LIKELY THAT
ANY SNOW WILL OCCUR IN THOSE AREAS TONIGHT OR TOMORROW WITH THE
BEST UPPER LEVEL FORCING WELL TO THE SOUTH.

WILL HAVE TO KEEP AN EYE ON HOW THE UPPER LEVELS EVOLVE EARLY NEXT
WEEK. MODELS SHOWING A CUT OFF LOW EJECTING NORTHEASTWARD OUT OF
CALIFORNIA AS A KICKER DROPS SOUTH OFF THE PACIFIC NORTHWEST
COAST. ECMWF INITIALLY KEEPS MUCH OF THE ENERGY OVER SOUTHCENTRAL
WYOMING MONDAY INTO MONDAY NIGHT AND THEN QUICKLY PUSHES THINGS
EASTWARD. THE GFS BRINGS THE MAIN ENERGY OVER FAR SOUTHEAST
WYOMING AND PRODUCES HIGHER AMOUNTS OF PRECIPITATION THERE. NOT
CONFIDENT IN EITHER SOLUTION AND SOMEWHAT SURPRISED HOW MUCH
PRECIPITATION THE MODELS ARE PRODUCING GIVEN THE PLACEMENT OF THE
UPPER LEVEL JET.

DEPENDING ON THE NEXT ROUND OF MODEL RUNS...MAY NEED WINTER WEATHER
HEADLINES FOR SOUTHCENTRAL WYOMING MONDAY THROUGH MONDAY NIGHT.
LIGHT SNOW COULD START FALLING IN THAT AREA LATE SUNDAY NIGHT BUT
AT THIS TIME IT APPEARS A MAJORITY OF THE SNOW WILL FALL AFTER 12Z
MONDAY THROUGH MONDAY NIGHT ACROSS THIS AREA.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 315 PM MST SAT FEB 28 2015

MAIN FORECAST CONCERN IN THE MEDIUM RANGE WILL BE THE CONTINUING
WINTER WEATHER EVENT ON TUESDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT WITH THIS STORM SYSTEM...SHOWING A SECONDARY SHORTWAVE
ALOFT DIGGING SOUTHWARD...WHICH WILL BE ASSOCIATED WITH THE
ARCTIC AIRMASS MOVING INTO WYOMING EARLY TUESDAY MORNING. HIGH
TEMPERATURES ON TUESDAY WILL LIKELY BE SIMILAR TO THE LOW
TEMPERATURES MONDAY NIGHT...AND GENERALLY IN THE TEENS TO LOW 20S.
TEMPERATURES WILL LOWER INTO THE SINGLE DIGITS AND LOW TEENS
THROUGH THE AFTERNOON AS THE 1035MB ARCTIC HIGH AT THE SURFACE
MOVES INTO THE AREA. KEPT A 60 PCT TO 80 PCT CHANCE OF SNOW FOR
MOST OF SOUTHEAST WYOMING INTO TUESDAY EVENING FOR AN ADDITIONAL 1
TO 3 INCHES OF SNOW ACCUMULATION. LOW TEMPERATURES TUESDAY NIGHT
WILL BE TRICKY AND WILL GREATLY DEPEND ON THE EXTENT OF SURFACE
SNOW COVER...DEPTH...AND IF SKIES CLEAR OUT OR NOT. CONSIDERING HOW
PROGRESSIVE THE SYSTEM IS AS INDICATED BY MODELS...BELIEVE MOST OF
THE FORECAST AREA AND ESPECIALLY NORTH OF I80...WILL HAVE CLEARING
SKIES OVERNIGHT. LOW TEMPERATURES MAY APPROACH -15 TO -20 IN THE
MORE SHELTERED VALLEYS ACROSS SOUTHEAST WYOMING WITH THE CENTER OF
THE ARCTIC HIGH JUST EAST OF THE LARAMIE RANGE.
ELSEWHERE...TEMPERATURES BETWEEN -5 TO -10 APPEAR LIKELY AT THIS
TIME IF BROKEN TO OVERCAST CONDITIONS CONTINUE THROUGH MOST OF THE
NIGHT.

WEDNESDAY THROUGH THE END OF THE WEEK...SOME FLURRIES ARE POSSIBLE
AS THE STORM SYSTEM EXITS THE REGION TO OUR SOUTH. WEDNESDAY WILL
BE THE COLDEST DAY OF THE WEEK WITH HIGHS STRUGGLING TO REACH THE
LOW TO MID TEENS. KEPT HIGHS A FEW DEGREES ABOVE MOS...BUT GAMBLING
THAT THE WESTERLY WINDS AND MARCH SUNSHINE WILL RESULT IN
TEMPERATURES A FEW DEGREES HIGHER THAN GUIDANCE.
OTHERWISE...TEMPERATURES MAY BE STUCK IN THE SINGLE DIGITS THROUGH
THE AFTERNOON. EITHER WAY...A WARMING TREND IS EXPECTED FOR THE
REMAINDER OF THE WEEK AS THE STRONG EASTERN PACIFIC RIDGE EXPANDS
EASTWARD A BIT INTO THE CENTRAL AND SOUTHERN ROCKY MOUNTAINS. DUE
TO POTENTIAL SNOW COVER...DID KEEP TEMPERATURES LOWER THAN MOS
THROUGH THE WEEK...WITH TEMPERATURES ABOVE GUIDANCE BY NEXT
WEEKEND AS MOST OF THE SNOW SHOULD MELT BY THAT TIME. EXPECT HIGHS
TO RETURN TO THE 40S TO AROUND 50 BY FRIDAY AND SATURDAY
AFTERNOON.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 952 PM MST SAT FEB 28 2015

TOUGH FORECAST FOR OUR SOUTHEAST WYOMING AIRPORTS. RADAR SHOWING
AREA OF SNOW FILLING IN FROM KCYS TO KLAR...BUT IT IS NOT TOO
HEAVY AND BARELY RESTRICTING VISIBILITIES. GOING TO HOLD OFF
ONLOWERING CONDITIONS UNTIL AFTER 12Z AND CONFINE LOWER CONDITIONS
TO KLAR.

&&

.FIRE WEATHER...

ISSUED AT 240 AM MST SAT FEB 28 2015

C0LDER THAN NORMAL TEMPERATURES...AMPLE SURFACE MOISTURE FROM
SNOWFALL...AND HIGH RELATIVE HUMIDITIES WILL PRECLUDE FIRE WEATHER
CONCERNS THROUGH NEXT WEEK.

&&

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

$$

UPDATE...GCC
SHORT TERM...SML
LONG TERM...TJT
AVIATION...GCC
FIRE WEATHER...MAJ



000
FXUS65 KCYS 010500
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1000 PM MST SAT FEB 28 2015

.UPDATE...
ISSUED AT 952 PM MST SAT FEB 28 2015

LOOKING AT RADAR MOSAIC...SNOW IS REALLY HAVING A TOUGH TIME
GETTING OVER THE SOUTH LARAMIE RANGE THIS EVENING. GETTING SOME
SNOW WEST OF THE LARAMIE RANGE...BUT NOTHING SO FAR TO THE EAST.
WENT AHEAD AND LOWERED POPS SOME FOR THE OVERNIGHT HOURS. UPDATES
HAVE BEEN SENT.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 340 PM MST SAT FEB 28 2015

A FEW SNOW FLURRIES WILL LINGER ALONG THE EASTERN FRINGES OF THE
SOUTHERN LARAMIE RANGE THROUGH THIS AFTERNOON. THE MAIN CHANCES
FOR ACCUMULATING SNOW WILL OCCUR THIS EVENING AND INTO THE
OVERNIGHT AS SUBTLE SHORTWAVE FEATURES MOVE INTO SOUTHEAST WYOMING
FROM COLORADO...AND ELEVATED WARM ADVECTION DEVELOPS. THE BEST
CHANCES FOR SNOW ACCUMULATIONS OUTSIDE OF THE MOUNTAINS WILL BE
ALONG AND NEAR THE COLORADO BORDER BUT EVEN THERE ANY
ACCUMULATIONS WILL BE MINIMAL AND GENERALLY LESS THAN ONE INCH.
KEPT SLIGHT CHANCES GOING INTO EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE...BUT IT IS LOOKING LESS LIKELY THAT
ANY SNOW WILL OCCUR IN THOSE AREAS TONIGHT OR TOMORROW WITH THE
BEST UPPER LEVEL FORCING WELL TO THE SOUTH.

WILL HAVE TO KEEP AN EYE ON HOW THE UPPER LEVELS EVOLVE EARLY NEXT
WEEK. MODELS SHOWING A CUT OFF LOW EJECTING NORTHEASTWARD OUT OF
CALIFORNIA AS A KICKER DROPS SOUTH OFF THE PACIFIC NORTHWEST
COAST. ECMWF INITIALLY KEEPS MUCH OF THE ENERGY OVER SOUTHCENTRAL
WYOMING MONDAY INTO MONDAY NIGHT AND THEN QUICKLY PUSHES THINGS
EASTWARD. THE GFS BRINGS THE MAIN ENERGY OVER FAR SOUTHEAST
WYOMING AND PRODUCES HIGHER AMOUNTS OF PRECIPITATION THERE. NOT
CONFIDENT IN EITHER SOLUTION AND SOMEWHAT SURPRISED HOW MUCH
PRECIPITATION THE MODELS ARE PRODUCING GIVEN THE PLACEMENT OF THE
UPPER LEVEL JET.

DEPENDING ON THE NEXT ROUND OF MODEL RUNS...MAY NEED WINTER WEATHER
HEADLINES FOR SOUTHCENTRAL WYOMING MONDAY THROUGH MONDAY NIGHT.
LIGHT SNOW COULD START FALLING IN THAT AREA LATE SUNDAY NIGHT BUT
AT THIS TIME IT APPEARS A MAJORITY OF THE SNOW WILL FALL AFTER 12Z
MONDAY THROUGH MONDAY NIGHT ACROSS THIS AREA.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 315 PM MST SAT FEB 28 2015

MAIN FORECAST CONCERN IN THE MEDIUM RANGE WILL BE THE CONTINUING
WINTER WEATHER EVENT ON TUESDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT WITH THIS STORM SYSTEM...SHOWING A SECONDARY SHORTWAVE
ALOFT DIGGING SOUTHWARD...WHICH WILL BE ASSOCIATED WITH THE
ARCTIC AIRMASS MOVING INTO WYOMING EARLY TUESDAY MORNING. HIGH
TEMPERATURES ON TUESDAY WILL LIKELY BE SIMILAR TO THE LOW
TEMPERATURES MONDAY NIGHT...AND GENERALLY IN THE TEENS TO LOW 20S.
TEMPERATURES WILL LOWER INTO THE SINGLE DIGITS AND LOW TEENS
THROUGH THE AFTERNOON AS THE 1035MB ARCTIC HIGH AT THE SURFACE
MOVES INTO THE AREA. KEPT A 60 PCT TO 80 PCT CHANCE OF SNOW FOR
MOST OF SOUTHEAST WYOMING INTO TUESDAY EVENING FOR AN ADDITIONAL 1
TO 3 INCHES OF SNOW ACCUMULATION. LOW TEMPERATURES TUESDAY NIGHT
WILL BE TRICKY AND WILL GREATLY DEPEND ON THE EXTENT OF SURFACE
SNOW COVER...DEPTH...AND IF SKIES CLEAR OUT OR NOT. CONSIDERING HOW
PROGRESSIVE THE SYSTEM IS AS INDICATED BY MODELS...BELIEVE MOST OF
THE FORECAST AREA AND ESPECIALLY NORTH OF I80...WILL HAVE CLEARING
SKIES OVERNIGHT. LOW TEMPERATURES MAY APPROACH -15 TO -20 IN THE
MORE SHELTERED VALLEYS ACROSS SOUTHEAST WYOMING WITH THE CENTER OF
THE ARCTIC HIGH JUST EAST OF THE LARAMIE RANGE.
ELSEWHERE...TEMPERATURES BETWEEN -5 TO -10 APPEAR LIKELY AT THIS
TIME IF BROKEN TO OVERCAST CONDITIONS CONTINUE THROUGH MOST OF THE
NIGHT.

WEDNESDAY THROUGH THE END OF THE WEEK...SOME FLURRIES ARE POSSIBLE
AS THE STORM SYSTEM EXITS THE REGION TO OUR SOUTH. WEDNESDAY WILL
BE THE COLDEST DAY OF THE WEEK WITH HIGHS STRUGGLING TO REACH THE
LOW TO MID TEENS. KEPT HIGHS A FEW DEGREES ABOVE MOS...BUT GAMBLING
THAT THE WESTERLY WINDS AND MARCH SUNSHINE WILL RESULT IN
TEMPERATURES A FEW DEGREES HIGHER THAN GUIDANCE.
OTHERWISE...TEMPERATURES MAY BE STUCK IN THE SINGLE DIGITS THROUGH
THE AFTERNOON. EITHER WAY...A WARMING TREND IS EXPECTED FOR THE
REMAINDER OF THE WEEK AS THE STRONG EASTERN PACIFIC RIDGE EXPANDS
EASTWARD A BIT INTO THE CENTRAL AND SOUTHERN ROCKY MOUNTAINS. DUE
TO POTENTIAL SNOW COVER...DID KEEP TEMPERATURES LOWER THAN MOS
THROUGH THE WEEK...WITH TEMPERATURES ABOVE GUIDANCE BY NEXT
WEEKEND AS MOST OF THE SNOW SHOULD MELT BY THAT TIME. EXPECT HIGHS
TO RETURN TO THE 40S TO AROUND 50 BY FRIDAY AND SATURDAY
AFTERNOON.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 952 PM MST SAT FEB 28 2015

TOUGH FORECAST FOR OUR SOUTHEAST WYOMING AIRPORTS. RADAR SHOWING
AREA OF SNOW FILLING IN FROM KCYS TO KLAR...BUT IT IS NOT TOO
HEAVY AND BARELY RESTRICTING VISIBILITIES. GOING TO HOLD OFF
ONLOWERING CONDITIONS UNTIL AFTER 12Z AND CONFINE LOWER CONDITIONS
TO KLAR.

&&

.FIRE WEATHER...

ISSUED AT 240 AM MST SAT FEB 28 2015

C0LDER THAN NORMAL TEMPERATURES...AMPLE SURFACE MOISTURE FROM
SNOWFALL...AND HIGH RELATIVE HUMIDITIES WILL PRECLUDE FIRE WEATHER
CONCERNS THROUGH NEXT WEEK.

&&

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

$$

UPDATE...GCC
SHORT TERM...SML
LONG TERM...TJT
AVIATION...GCC
FIRE WEATHER...MAJ




000
FXUS63 KUNR 010412
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
912 PM MST SAT FEB 28 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 205 PM MST SAT FEB 28 2015

UPPER TROUGH STRETCHES ACROSS THE CENTRAL AND WESTERN
STATES...WITH LOW SPINNING OVER CA. NORTHERNMOST WAVE WITHIN THE
TROUGH IS PUSHING THROUGH MT. AXIS OF SURFACE TROUGH HAS PASSED
THROUGH THE WESTERN DAKOTAS. COLDER AIR AND CLOUDS ARE MOVING IN
FROM THE NORTHWEST. TEMPS HAVE RISEN INTO THE LOWER 30S ACROSS SOUTH
CENTRAL SD...BUT THE NORTHWESTERN CWA REMAINS IN THE TEENS.
NORTHWEST WINDS ARE AROUND 20 KTS ACROSS THE WESTERN SD PLAINS.

UPPER WAVE WILL QUICKLY SWEEP THROUGH THE NORTHERN PLAINS TONIGHT AS
CLOSED LOW CONTINUES TO SPIN OVER THE SOUTHWEST US. PRECIPITATION
ASSOCIATED WITH THE SOUTHWEST LOW MAY REACH PARTS OF NORTHEAST WY
AND FAR SOUTHWEST SD TONIGHT...BUT WITH SURFACE HIGH SLIDING INTO
THE REGION...EXPECT MAINLY DRY CONDITIONS. DETERMINISTIC MODELS HAVE
BROUGHT PRECIP FARTHER SOUTH OF THE CWA...BUT THE SREF CONTINUES TO
SHOW SOME SLIGHT CHANCE POPS. DID KEEP SLIGHTLY HIGHER POPS OVER THE
SOUTHERN HILLS/CONVERGENCE ZONE. LOWS TONIGHT WILL BE IN THE
SINGLE DIGITS.

UPPER FLOW BECOMES MORE NORTHWESTERLY ON SUNDAY AND SURFACE HIGH
CONTINUES TO PUSH INTO THE REGION. PRESSURE GRADIENT TIGHTENS A BIT
OVER NORTHWEST SD BY MIDDAY SO EXPECT SOME BREEZY WINDS ACROSS THE
WESTERN SD PLAINS. ADDED A FEW UPSLOPE SNOW SHOWERS OVER THE
NORTHERN HILLS AS FROUDE NUMBER SHOOTS UP IN THE AFTERNOON.
ELSEWHERE...SKIES WILL BE MOSTLY SUNNY. HIGHS WILL BE IN THE 20S TO
LOWER 30S. UNDER MOSTLY CLEAR SKIES...LOWS WILL BE IN THE SINGLE
DIGITS TO LOWER TEENS.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 205 PM MST SAT FEB 28 2015

MONDAY WILL FEATURE A BRIEF WARM UP ACROSS THE CWA AS SURFACE WINDS
SWITCH FROM NW TO THE SOUTH AND UPPER LEVEL FLOW TURNS MORE
WESTERLY. AN ARCTIC FRONT WILL COME CRASHING INTO THE CWA BY MONDAY
EVENING...BRINGING STRONG NORTHWESTERLY WINDS...BITTERLY COLD
TEMPERATURES...AND LIGHT ACCUMULATIONS OF SNOW. TEMPERATURES
DURING THE DAY TUESDAY WILL STRUGGLE TO RISE AS STRONG CAA TAKES
PLACE.

THE COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP IS
EXPECTED. THIS NEXT WARM UP... HOWEVER... LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE WELL ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 911 PM MST SAT FEB 28 2015

AREAS OF MVFR CIGS AT TIMES CAN BE EXPECTED ACROSS NERN WY AND FAR
WRN SD THROUGH THE PERIOD...WITH VFR CONDITIONS ELSEWHERE.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...MCKEMY
AVIATION...JOHNSON







000
FXUS63 KUNR 010412
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
912 PM MST SAT FEB 28 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 205 PM MST SAT FEB 28 2015

UPPER TROUGH STRETCHES ACROSS THE CENTRAL AND WESTERN
STATES...WITH LOW SPINNING OVER CA. NORTHERNMOST WAVE WITHIN THE
TROUGH IS PUSHING THROUGH MT. AXIS OF SURFACE TROUGH HAS PASSED
THROUGH THE WESTERN DAKOTAS. COLDER AIR AND CLOUDS ARE MOVING IN
FROM THE NORTHWEST. TEMPS HAVE RISEN INTO THE LOWER 30S ACROSS SOUTH
CENTRAL SD...BUT THE NORTHWESTERN CWA REMAINS IN THE TEENS.
NORTHWEST WINDS ARE AROUND 20 KTS ACROSS THE WESTERN SD PLAINS.

UPPER WAVE WILL QUICKLY SWEEP THROUGH THE NORTHERN PLAINS TONIGHT AS
CLOSED LOW CONTINUES TO SPIN OVER THE SOUTHWEST US. PRECIPITATION
ASSOCIATED WITH THE SOUTHWEST LOW MAY REACH PARTS OF NORTHEAST WY
AND FAR SOUTHWEST SD TONIGHT...BUT WITH SURFACE HIGH SLIDING INTO
THE REGION...EXPECT MAINLY DRY CONDITIONS. DETERMINISTIC MODELS HAVE
BROUGHT PRECIP FARTHER SOUTH OF THE CWA...BUT THE SREF CONTINUES TO
SHOW SOME SLIGHT CHANCE POPS. DID KEEP SLIGHTLY HIGHER POPS OVER THE
SOUTHERN HILLS/CONVERGENCE ZONE. LOWS TONIGHT WILL BE IN THE
SINGLE DIGITS.

UPPER FLOW BECOMES MORE NORTHWESTERLY ON SUNDAY AND SURFACE HIGH
CONTINUES TO PUSH INTO THE REGION. PRESSURE GRADIENT TIGHTENS A BIT
OVER NORTHWEST SD BY MIDDAY SO EXPECT SOME BREEZY WINDS ACROSS THE
WESTERN SD PLAINS. ADDED A FEW UPSLOPE SNOW SHOWERS OVER THE
NORTHERN HILLS AS FROUDE NUMBER SHOOTS UP IN THE AFTERNOON.
ELSEWHERE...SKIES WILL BE MOSTLY SUNNY. HIGHS WILL BE IN THE 20S TO
LOWER 30S. UNDER MOSTLY CLEAR SKIES...LOWS WILL BE IN THE SINGLE
DIGITS TO LOWER TEENS.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 205 PM MST SAT FEB 28 2015

MONDAY WILL FEATURE A BRIEF WARM UP ACROSS THE CWA AS SURFACE WINDS
SWITCH FROM NW TO THE SOUTH AND UPPER LEVEL FLOW TURNS MORE
WESTERLY. AN ARCTIC FRONT WILL COME CRASHING INTO THE CWA BY MONDAY
EVENING...BRINGING STRONG NORTHWESTERLY WINDS...BITTERLY COLD
TEMPERATURES...AND LIGHT ACCUMULATIONS OF SNOW. TEMPERATURES
DURING THE DAY TUESDAY WILL STRUGGLE TO RISE AS STRONG CAA TAKES
PLACE.

THE COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP IS
EXPECTED. THIS NEXT WARM UP... HOWEVER... LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE WELL ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 911 PM MST SAT FEB 28 2015

AREAS OF MVFR CIGS AT TIMES CAN BE EXPECTED ACROSS NERN WY AND FAR
WRN SD THROUGH THE PERIOD...WITH VFR CONDITIONS ELSEWHERE.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...MCKEMY
AVIATION...JOHNSON






000
FXUS63 KUNR 010412
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
912 PM MST SAT FEB 28 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 205 PM MST SAT FEB 28 2015

UPPER TROUGH STRETCHES ACROSS THE CENTRAL AND WESTERN
STATES...WITH LOW SPINNING OVER CA. NORTHERNMOST WAVE WITHIN THE
TROUGH IS PUSHING THROUGH MT. AXIS OF SURFACE TROUGH HAS PASSED
THROUGH THE WESTERN DAKOTAS. COLDER AIR AND CLOUDS ARE MOVING IN
FROM THE NORTHWEST. TEMPS HAVE RISEN INTO THE LOWER 30S ACROSS SOUTH
CENTRAL SD...BUT THE NORTHWESTERN CWA REMAINS IN THE TEENS.
NORTHWEST WINDS ARE AROUND 20 KTS ACROSS THE WESTERN SD PLAINS.

UPPER WAVE WILL QUICKLY SWEEP THROUGH THE NORTHERN PLAINS TONIGHT AS
CLOSED LOW CONTINUES TO SPIN OVER THE SOUTHWEST US. PRECIPITATION
ASSOCIATED WITH THE SOUTHWEST LOW MAY REACH PARTS OF NORTHEAST WY
AND FAR SOUTHWEST SD TONIGHT...BUT WITH SURFACE HIGH SLIDING INTO
THE REGION...EXPECT MAINLY DRY CONDITIONS. DETERMINISTIC MODELS HAVE
BROUGHT PRECIP FARTHER SOUTH OF THE CWA...BUT THE SREF CONTINUES TO
SHOW SOME SLIGHT CHANCE POPS. DID KEEP SLIGHTLY HIGHER POPS OVER THE
SOUTHERN HILLS/CONVERGENCE ZONE. LOWS TONIGHT WILL BE IN THE
SINGLE DIGITS.

UPPER FLOW BECOMES MORE NORTHWESTERLY ON SUNDAY AND SURFACE HIGH
CONTINUES TO PUSH INTO THE REGION. PRESSURE GRADIENT TIGHTENS A BIT
OVER NORTHWEST SD BY MIDDAY SO EXPECT SOME BREEZY WINDS ACROSS THE
WESTERN SD PLAINS. ADDED A FEW UPSLOPE SNOW SHOWERS OVER THE
NORTHERN HILLS AS FROUDE NUMBER SHOOTS UP IN THE AFTERNOON.
ELSEWHERE...SKIES WILL BE MOSTLY SUNNY. HIGHS WILL BE IN THE 20S TO
LOWER 30S. UNDER MOSTLY CLEAR SKIES...LOWS WILL BE IN THE SINGLE
DIGITS TO LOWER TEENS.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 205 PM MST SAT FEB 28 2015

MONDAY WILL FEATURE A BRIEF WARM UP ACROSS THE CWA AS SURFACE WINDS
SWITCH FROM NW TO THE SOUTH AND UPPER LEVEL FLOW TURNS MORE
WESTERLY. AN ARCTIC FRONT WILL COME CRASHING INTO THE CWA BY MONDAY
EVENING...BRINGING STRONG NORTHWESTERLY WINDS...BITTERLY COLD
TEMPERATURES...AND LIGHT ACCUMULATIONS OF SNOW. TEMPERATURES
DURING THE DAY TUESDAY WILL STRUGGLE TO RISE AS STRONG CAA TAKES
PLACE.

THE COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP IS
EXPECTED. THIS NEXT WARM UP... HOWEVER... LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE WELL ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 911 PM MST SAT FEB 28 2015

AREAS OF MVFR CIGS AT TIMES CAN BE EXPECTED ACROSS NERN WY AND FAR
WRN SD THROUGH THE PERIOD...WITH VFR CONDITIONS ELSEWHERE.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...MCKEMY
AVIATION...JOHNSON







000
FXUS63 KUNR 010412
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
912 PM MST SAT FEB 28 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 205 PM MST SAT FEB 28 2015

UPPER TROUGH STRETCHES ACROSS THE CENTRAL AND WESTERN
STATES...WITH LOW SPINNING OVER CA. NORTHERNMOST WAVE WITHIN THE
TROUGH IS PUSHING THROUGH MT. AXIS OF SURFACE TROUGH HAS PASSED
THROUGH THE WESTERN DAKOTAS. COLDER AIR AND CLOUDS ARE MOVING IN
FROM THE NORTHWEST. TEMPS HAVE RISEN INTO THE LOWER 30S ACROSS SOUTH
CENTRAL SD...BUT THE NORTHWESTERN CWA REMAINS IN THE TEENS.
NORTHWEST WINDS ARE AROUND 20 KTS ACROSS THE WESTERN SD PLAINS.

UPPER WAVE WILL QUICKLY SWEEP THROUGH THE NORTHERN PLAINS TONIGHT AS
CLOSED LOW CONTINUES TO SPIN OVER THE SOUTHWEST US. PRECIPITATION
ASSOCIATED WITH THE SOUTHWEST LOW MAY REACH PARTS OF NORTHEAST WY
AND FAR SOUTHWEST SD TONIGHT...BUT WITH SURFACE HIGH SLIDING INTO
THE REGION...EXPECT MAINLY DRY CONDITIONS. DETERMINISTIC MODELS HAVE
BROUGHT PRECIP FARTHER SOUTH OF THE CWA...BUT THE SREF CONTINUES TO
SHOW SOME SLIGHT CHANCE POPS. DID KEEP SLIGHTLY HIGHER POPS OVER THE
SOUTHERN HILLS/CONVERGENCE ZONE. LOWS TONIGHT WILL BE IN THE
SINGLE DIGITS.

UPPER FLOW BECOMES MORE NORTHWESTERLY ON SUNDAY AND SURFACE HIGH
CONTINUES TO PUSH INTO THE REGION. PRESSURE GRADIENT TIGHTENS A BIT
OVER NORTHWEST SD BY MIDDAY SO EXPECT SOME BREEZY WINDS ACROSS THE
WESTERN SD PLAINS. ADDED A FEW UPSLOPE SNOW SHOWERS OVER THE
NORTHERN HILLS AS FROUDE NUMBER SHOOTS UP IN THE AFTERNOON.
ELSEWHERE...SKIES WILL BE MOSTLY SUNNY. HIGHS WILL BE IN THE 20S TO
LOWER 30S. UNDER MOSTLY CLEAR SKIES...LOWS WILL BE IN THE SINGLE
DIGITS TO LOWER TEENS.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 205 PM MST SAT FEB 28 2015

MONDAY WILL FEATURE A BRIEF WARM UP ACROSS THE CWA AS SURFACE WINDS
SWITCH FROM NW TO THE SOUTH AND UPPER LEVEL FLOW TURNS MORE
WESTERLY. AN ARCTIC FRONT WILL COME CRASHING INTO THE CWA BY MONDAY
EVENING...BRINGING STRONG NORTHWESTERLY WINDS...BITTERLY COLD
TEMPERATURES...AND LIGHT ACCUMULATIONS OF SNOW. TEMPERATURES
DURING THE DAY TUESDAY WILL STRUGGLE TO RISE AS STRONG CAA TAKES
PLACE.

THE COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP IS
EXPECTED. THIS NEXT WARM UP... HOWEVER... LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE WELL ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 911 PM MST SAT FEB 28 2015

AREAS OF MVFR CIGS AT TIMES CAN BE EXPECTED ACROSS NERN WY AND FAR
WRN SD THROUGH THE PERIOD...WITH VFR CONDITIONS ELSEWHERE.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...MCKEMY
AVIATION...JOHNSON






000
FXUS65 KCYS 282237
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
337 PM MST SAT FEB 28 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 340 PM MST SAT FEB 28 2015

A FEW SNOW FLURRIES WILL LINGER ALONG THE EASTERN FRINGES OF THE
SOUTHERN LARAMIE RANGE THROUGH THIS AFTERNOON. THE MAIN CHANCES
FOR ACCUMULATING SNOW WILL OCCUR THIS EVENING AND INTO THE
OVERNIGHT AS SUBTLE SHORTWAVE FEATURES MOVE INTO SOUTHEAST WYOMING
FROM COLORADO...AND ELEVATED WARM ADVECTION DEVELOPS. THE BEST
CHANCES FOR SNOW ACCUMULATIONS OUTSIDE OF THE MOUNTAINS WILL BE
ALONG AND NEAR THE COLORADO BORDER BUT EVEN THERE ANY
ACCUMULATIONS WILL BE MINIMAL AND GENERALLY LESS THAN ONE INCH.
KEPT SLIGHT CHANCES GOING INTO EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE...BUT IT IS LOOKING LESS LIKELY THAT
ANY SNOW WILL OCCUR IN THOSE AREAS TONIGHT OR TOMORROW WITH THE
BEST UPPER LEVEL FORCING WELL TO THE SOUTH.

WILL HAVE TO KEEP AN EYE ON HOW THE UPPER LEVELS EVOLVE EARLY NEXT
WEEK. MODELS SHOWING A CUT OFF LOW EJECTING NORTHEASTWARD OUT OF
CALIFORNIA AS A KICKER DROPS SOUTH OFF THE PACIFIC NORTHWEST
COAST. ECMWF INITIALLY KEEPS MUCH OF THE ENERGY OVER SOUTHCENTRAL
WYOMING MONDAY INTO MONDAY NIGHT AND THEN QUICKLY PUSHES THINGS
EASTWARD. THE GFS BRINGS THE MAIN ENERGY OVER FAR SOUTHEAST
WYOMING AND PRODUCES HIGHER AMOUNTS OF PRECIPITATION THERE. NOT
CONFIDENT IN EITHER SOLUTION AND SOMEWHAT SURPRISED HOW MUCH
PRECIPITATION THE MODELS ARE PRODUCING GIVEN THE PLACEMENT OF THE
UPPER LEVEL JET.

DEPENDING ON THE NEXT ROUND OF MODEL RUNS...MAY NEED WINTER WEATHER
HEADLINES FOR SOUTHCENTRAL WYOMING MONDAY THROUGH MONDAY NIGHT.
LIGHT SNOW COULD START FALLING IN THAT AREA LATE SUNDAY NIGHT BUT
AT THIS TIME IT APPEARS A MAJORITY OF THE SNOW WILL FALL AFTER 12Z
MONDAY THROUGH MONDAY NIGHT ACROSS THIS AREA.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 315 PM MST SAT FEB 28 2015

MAIN FORECAST CONCERN IN THE MEDIUM RANGE WILL BE THE CONTINUING
WINTER WEATHER EVENT ON TUESDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT WITH THIS STORM SYSTEM...SHOWING A SECONDARY SHORTWAVE
ALOFT DIGGING SOUTHWARD...WHICH WILL BE ASSOCIATED WITH THE
ARCTIC AIRMASS MOVING INTO WYOMING EARLY TUESDAY MORNING. HIGH
TEMPERATURES ON TUESDAY WILL LIKELY BE SIMILAR TO THE LOW
TEMPERATURES MONDAY NIGHT...AND GENERALLY IN THE TEENS TO LOW 20S.
TEMPERATURES WILL LOWER INTO THE SINGLE DIGITS AND LOW TEENS
THROUGH THE AFTERNOON AS THE 1035MB ARCTIC HIGH AT THE SURFACE
MOVES INTO THE AREA. KEPT A 60 PCT TO 80 PCT CHANCE OF SNOW FOR
MOST OF SOUTHEAST WYOMING INTO TUESDAY EVENING FOR AN ADDITIONAL 1
TO 3 INCHES OF SNOW ACCUMULATION. LOW TEMPERATURES TUESDAY NIGHT
WILL BE TRICKY AND WILL GREATLY DEPEND ON THE EXTENT OF SURFACE
SNOW COVER...DEPTH...AND IF SKIES CLEAR OUT OR NOT. CONSIDERING HOW
PROGRESSIVE THE SYSTEM IS AS INDICATED BY MODELS...BELIEVE MOST OF
THE FORECAST AREA AND ESPECIALLY NORTH OF I80...WILL HAVE CLEARING
SKIES OVERNIGHT. LOW TEMPERATURES MAY APPROACH -15 TO -20 IN THE
MORE SHELTERED VALLEYS ACROSS SOUTHEAST WYOMING WITH THE CENTER OF
THE ARCTIC HIGH JUST EAST OF THE LARAMIE RANGE.
ELSEWHERE...TEMPERATURES BETWEEN -5 TO -10 APPEAR LIKELY AT THIS
TIME IF BROKEN TO OVERCAST CONDITIONS CONTINUE THROUGH MOST OF THE
NIGHT.

WEDNESDAY THROUGH THE END OF THE WEEK...SOME FLURRIES ARE POSSIBLE
AS THE STORM SYSTEM EXITS THE REGION TO OUR SOUTH. WEDNESDAY WILL
BE THE COLDEST DAY OF THE WEEK WITH HIGHS STRUGGLING TO REACH THE
LOW TO MID TEENS. KEPT HIGHS A FEW DEGREES ABOVE MOS...BUT GAMBLING
THAT THE WESTERLY WINDS AND MARCH SUNSHINE WILL RESULT IN
TEMPERATURES A FEW DEGREES HIGHER THAN GUIDANCE.
OTHERWISE...TEMPERATURES MAY BE STUCK IN THE SINGLE DIGITS THROUGH
THE AFTERNOON. EITHER WAY...A WARMING TREND IS EXPECTED FOR THE
REMAINDER OF THE WEEK AS THE STRONG EASTERN PACIFIC RIDGE EXPANDS
EASTWARD A BIT INTO THE CENTRAL AND SOUTHERN ROCKY MOUNTAINS. DUE
TO POTENTIAL SNOW COVER...DID KEEP TEMPERATURES LOWER THAN MOS
THROUGH THE WEEK...WITH TEMPERATURES ABOVE GUIDANCE BY NEXT
WEEKEND AS MOST OF THE SNOW SHOULD MELT BY THAT TIME. EXPECT HIGHS
TO RETURN TO THE 40S TO AROUND 50 BY FRIDAY AND SATURDAY
AFTERNOON.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH SUNDAY EVENING)
ISSUED AT 231 PM MST SAT FEB 28 2015

MVFR CIGS WILL CONTINUE FOR PORTIONS OF SOUTHEAST WYOMING AND
WESTERN NEBRASKA LATE THIS AFTERNOON AND INTO THIS EVENING DUE TO
LLVL UPSLOPE FLOW. ISOLATE SNOW FLURRIES WILL GENERALLY STAY NEAR
KCYS INTO THIS EVENING...UNTIL LIGHT SNOW DEVELOPS FROM SOUTH TO
NORTH ALONG THE I80 CORRIDOR BY 04Z LATE THIS EVENING. IFR
CONDITIONS AND LIGHT SNOW ARE EXPECTED NEAR KLAR...KCYS...AND
POSSIBLY KSNY AFTER 03Z. THE NORTHWARD EXTENT OF THIS SNOW SHOULD
REMAIN SOUTH OF A LINE FROM KRWL TO KAIA. THIS SNOW SHOULD
DIMINISH IN INTENSITY BY SUNDAY MORNING WITH A RETURN TO MVFR OR
HIGHER CONDITIONS BY THE AFTERNOON.

&&

.FIRE WEATHER...

ISSUED AT 240 AM MST SAT FEB 28 2015

C0LDER THAN NORMAL TEMPERATURES...AMPLE SURFACE MOISTURE FROM
SNOWFALL...AND HIGH RELATIVE HUMIDITIES WILL PRECLUDE FIRE WEATHER
CONCERNS THROUGH NEXT WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...

WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...SML
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...MAJ




000
FXUS65 KCYS 282237
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
337 PM MST SAT FEB 28 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 340 PM MST SAT FEB 28 2015

A FEW SNOW FLURRIES WILL LINGER ALONG THE EASTERN FRINGES OF THE
SOUTHERN LARAMIE RANGE THROUGH THIS AFTERNOON. THE MAIN CHANCES
FOR ACCUMULATING SNOW WILL OCCUR THIS EVENING AND INTO THE
OVERNIGHT AS SUBTLE SHORTWAVE FEATURES MOVE INTO SOUTHEAST WYOMING
FROM COLORADO...AND ELEVATED WARM ADVECTION DEVELOPS. THE BEST
CHANCES FOR SNOW ACCUMULATIONS OUTSIDE OF THE MOUNTAINS WILL BE
ALONG AND NEAR THE COLORADO BORDER BUT EVEN THERE ANY
ACCUMULATIONS WILL BE MINIMAL AND GENERALLY LESS THAN ONE INCH.
KEPT SLIGHT CHANCES GOING INTO EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE...BUT IT IS LOOKING LESS LIKELY THAT
ANY SNOW WILL OCCUR IN THOSE AREAS TONIGHT OR TOMORROW WITH THE
BEST UPPER LEVEL FORCING WELL TO THE SOUTH.

WILL HAVE TO KEEP AN EYE ON HOW THE UPPER LEVELS EVOLVE EARLY NEXT
WEEK. MODELS SHOWING A CUT OFF LOW EJECTING NORTHEASTWARD OUT OF
CALIFORNIA AS A KICKER DROPS SOUTH OFF THE PACIFIC NORTHWEST
COAST. ECMWF INITIALLY KEEPS MUCH OF THE ENERGY OVER SOUTHCENTRAL
WYOMING MONDAY INTO MONDAY NIGHT AND THEN QUICKLY PUSHES THINGS
EASTWARD. THE GFS BRINGS THE MAIN ENERGY OVER FAR SOUTHEAST
WYOMING AND PRODUCES HIGHER AMOUNTS OF PRECIPITATION THERE. NOT
CONFIDENT IN EITHER SOLUTION AND SOMEWHAT SURPRISED HOW MUCH
PRECIPITATION THE MODELS ARE PRODUCING GIVEN THE PLACEMENT OF THE
UPPER LEVEL JET.

DEPENDING ON THE NEXT ROUND OF MODEL RUNS...MAY NEED WINTER WEATHER
HEADLINES FOR SOUTHCENTRAL WYOMING MONDAY THROUGH MONDAY NIGHT.
LIGHT SNOW COULD START FALLING IN THAT AREA LATE SUNDAY NIGHT BUT
AT THIS TIME IT APPEARS A MAJORITY OF THE SNOW WILL FALL AFTER 12Z
MONDAY THROUGH MONDAY NIGHT ACROSS THIS AREA.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 315 PM MST SAT FEB 28 2015

MAIN FORECAST CONCERN IN THE MEDIUM RANGE WILL BE THE CONTINUING
WINTER WEATHER EVENT ON TUESDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT WITH THIS STORM SYSTEM...SHOWING A SECONDARY SHORTWAVE
ALOFT DIGGING SOUTHWARD...WHICH WILL BE ASSOCIATED WITH THE
ARCTIC AIRMASS MOVING INTO WYOMING EARLY TUESDAY MORNING. HIGH
TEMPERATURES ON TUESDAY WILL LIKELY BE SIMILAR TO THE LOW
TEMPERATURES MONDAY NIGHT...AND GENERALLY IN THE TEENS TO LOW 20S.
TEMPERATURES WILL LOWER INTO THE SINGLE DIGITS AND LOW TEENS
THROUGH THE AFTERNOON AS THE 1035MB ARCTIC HIGH AT THE SURFACE
MOVES INTO THE AREA. KEPT A 60 PCT TO 80 PCT CHANCE OF SNOW FOR
MOST OF SOUTHEAST WYOMING INTO TUESDAY EVENING FOR AN ADDITIONAL 1
TO 3 INCHES OF SNOW ACCUMULATION. LOW TEMPERATURES TUESDAY NIGHT
WILL BE TRICKY AND WILL GREATLY DEPEND ON THE EXTENT OF SURFACE
SNOW COVER...DEPTH...AND IF SKIES CLEAR OUT OR NOT. CONSIDERING HOW
PROGRESSIVE THE SYSTEM IS AS INDICATED BY MODELS...BELIEVE MOST OF
THE FORECAST AREA AND ESPECIALLY NORTH OF I80...WILL HAVE CLEARING
SKIES OVERNIGHT. LOW TEMPERATURES MAY APPROACH -15 TO -20 IN THE
MORE SHELTERED VALLEYS ACROSS SOUTHEAST WYOMING WITH THE CENTER OF
THE ARCTIC HIGH JUST EAST OF THE LARAMIE RANGE.
ELSEWHERE...TEMPERATURES BETWEEN -5 TO -10 APPEAR LIKELY AT THIS
TIME IF BROKEN TO OVERCAST CONDITIONS CONTINUE THROUGH MOST OF THE
NIGHT.

WEDNESDAY THROUGH THE END OF THE WEEK...SOME FLURRIES ARE POSSIBLE
AS THE STORM SYSTEM EXITS THE REGION TO OUR SOUTH. WEDNESDAY WILL
BE THE COLDEST DAY OF THE WEEK WITH HIGHS STRUGGLING TO REACH THE
LOW TO MID TEENS. KEPT HIGHS A FEW DEGREES ABOVE MOS...BUT GAMBLING
THAT THE WESTERLY WINDS AND MARCH SUNSHINE WILL RESULT IN
TEMPERATURES A FEW DEGREES HIGHER THAN GUIDANCE.
OTHERWISE...TEMPERATURES MAY BE STUCK IN THE SINGLE DIGITS THROUGH
THE AFTERNOON. EITHER WAY...A WARMING TREND IS EXPECTED FOR THE
REMAINDER OF THE WEEK AS THE STRONG EASTERN PACIFIC RIDGE EXPANDS
EASTWARD A BIT INTO THE CENTRAL AND SOUTHERN ROCKY MOUNTAINS. DUE
TO POTENTIAL SNOW COVER...DID KEEP TEMPERATURES LOWER THAN MOS
THROUGH THE WEEK...WITH TEMPERATURES ABOVE GUIDANCE BY NEXT
WEEKEND AS MOST OF THE SNOW SHOULD MELT BY THAT TIME. EXPECT HIGHS
TO RETURN TO THE 40S TO AROUND 50 BY FRIDAY AND SATURDAY
AFTERNOON.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH SUNDAY EVENING)
ISSUED AT 231 PM MST SAT FEB 28 2015

MVFR CIGS WILL CONTINUE FOR PORTIONS OF SOUTHEAST WYOMING AND
WESTERN NEBRASKA LATE THIS AFTERNOON AND INTO THIS EVENING DUE TO
LLVL UPSLOPE FLOW. ISOLATE SNOW FLURRIES WILL GENERALLY STAY NEAR
KCYS INTO THIS EVENING...UNTIL LIGHT SNOW DEVELOPS FROM SOUTH TO
NORTH ALONG THE I80 CORRIDOR BY 04Z LATE THIS EVENING. IFR
CONDITIONS AND LIGHT SNOW ARE EXPECTED NEAR KLAR...KCYS...AND
POSSIBLY KSNY AFTER 03Z. THE NORTHWARD EXTENT OF THIS SNOW SHOULD
REMAIN SOUTH OF A LINE FROM KRWL TO KAIA. THIS SNOW SHOULD
DIMINISH IN INTENSITY BY SUNDAY MORNING WITH A RETURN TO MVFR OR
HIGHER CONDITIONS BY THE AFTERNOON.

&&

.FIRE WEATHER...

ISSUED AT 240 AM MST SAT FEB 28 2015

C0LDER THAN NORMAL TEMPERATURES...AMPLE SURFACE MOISTURE FROM
SNOWFALL...AND HIGH RELATIVE HUMIDITIES WILL PRECLUDE FIRE WEATHER
CONCERNS THROUGH NEXT WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...

WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...SML
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...MAJ



000
FXUS65 KCYS 282237
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
337 PM MST SAT FEB 28 2015

.SHORT TERM...(THIS EVENING THROUGH MONDAY NIGHT)
ISSUED AT 340 PM MST SAT FEB 28 2015

A FEW SNOW FLURRIES WILL LINGER ALONG THE EASTERN FRINGES OF THE
SOUTHERN LARAMIE RANGE THROUGH THIS AFTERNOON. THE MAIN CHANCES
FOR ACCUMULATING SNOW WILL OCCUR THIS EVENING AND INTO THE
OVERNIGHT AS SUBTLE SHORTWAVE FEATURES MOVE INTO SOUTHEAST WYOMING
FROM COLORADO...AND ELEVATED WARM ADVECTION DEVELOPS. THE BEST
CHANCES FOR SNOW ACCUMULATIONS OUTSIDE OF THE MOUNTAINS WILL BE
ALONG AND NEAR THE COLORADO BORDER BUT EVEN THERE ANY
ACCUMULATIONS WILL BE MINIMAL AND GENERALLY LESS THAN ONE INCH.
KEPT SLIGHT CHANCES GOING INTO EAST CENTRAL WYOMING AND THE
NORTHERN NEBRASKA PANHANDLE...BUT IT IS LOOKING LESS LIKELY THAT
ANY SNOW WILL OCCUR IN THOSE AREAS TONIGHT OR TOMORROW WITH THE
BEST UPPER LEVEL FORCING WELL TO THE SOUTH.

WILL HAVE TO KEEP AN EYE ON HOW THE UPPER LEVELS EVOLVE EARLY NEXT
WEEK. MODELS SHOWING A CUT OFF LOW EJECTING NORTHEASTWARD OUT OF
CALIFORNIA AS A KICKER DROPS SOUTH OFF THE PACIFIC NORTHWEST
COAST. ECMWF INITIALLY KEEPS MUCH OF THE ENERGY OVER SOUTHCENTRAL
WYOMING MONDAY INTO MONDAY NIGHT AND THEN QUICKLY PUSHES THINGS
EASTWARD. THE GFS BRINGS THE MAIN ENERGY OVER FAR SOUTHEAST
WYOMING AND PRODUCES HIGHER AMOUNTS OF PRECIPITATION THERE. NOT
CONFIDENT IN EITHER SOLUTION AND SOMEWHAT SURPRISED HOW MUCH
PRECIPITATION THE MODELS ARE PRODUCING GIVEN THE PLACEMENT OF THE
UPPER LEVEL JET.

DEPENDING ON THE NEXT ROUND OF MODEL RUNS...MAY NEED WINTER WEATHER
HEADLINES FOR SOUTHCENTRAL WYOMING MONDAY THROUGH MONDAY NIGHT.
LIGHT SNOW COULD START FALLING IN THAT AREA LATE SUNDAY NIGHT BUT
AT THIS TIME IT APPEARS A MAJORITY OF THE SNOW WILL FALL AFTER 12Z
MONDAY THROUGH MONDAY NIGHT ACROSS THIS AREA.

.LONG TERM...(TUESDAY THROUGH SATURDAY)
ISSUED AT 315 PM MST SAT FEB 28 2015

MAIN FORECAST CONCERN IN THE MEDIUM RANGE WILL BE THE CONTINUING
WINTER WEATHER EVENT ON TUESDAY. MODELS ARE IN PRETTY GOOD
AGREEMENT WITH THIS STORM SYSTEM...SHOWING A SECONDARY SHORTWAVE
ALOFT DIGGING SOUTHWARD...WHICH WILL BE ASSOCIATED WITH THE
ARCTIC AIRMASS MOVING INTO WYOMING EARLY TUESDAY MORNING. HIGH
TEMPERATURES ON TUESDAY WILL LIKELY BE SIMILAR TO THE LOW
TEMPERATURES MONDAY NIGHT...AND GENERALLY IN THE TEENS TO LOW 20S.
TEMPERATURES WILL LOWER INTO THE SINGLE DIGITS AND LOW TEENS
THROUGH THE AFTERNOON AS THE 1035MB ARCTIC HIGH AT THE SURFACE
MOVES INTO THE AREA. KEPT A 60 PCT TO 80 PCT CHANCE OF SNOW FOR
MOST OF SOUTHEAST WYOMING INTO TUESDAY EVENING FOR AN ADDITIONAL 1
TO 3 INCHES OF SNOW ACCUMULATION. LOW TEMPERATURES TUESDAY NIGHT
WILL BE TRICKY AND WILL GREATLY DEPEND ON THE EXTENT OF SURFACE
SNOW COVER...DEPTH...AND IF SKIES CLEAR OUT OR NOT. CONSIDERING HOW
PROGRESSIVE THE SYSTEM IS AS INDICATED BY MODELS...BELIEVE MOST OF
THE FORECAST AREA AND ESPECIALLY NORTH OF I80...WILL HAVE CLEARING
SKIES OVERNIGHT. LOW TEMPERATURES MAY APPROACH -15 TO -20 IN THE
MORE SHELTERED VALLEYS ACROSS SOUTHEAST WYOMING WITH THE CENTER OF
THE ARCTIC HIGH JUST EAST OF THE LARAMIE RANGE.
ELSEWHERE...TEMPERATURES BETWEEN -5 TO -10 APPEAR LIKELY AT THIS
TIME IF BROKEN TO OVERCAST CONDITIONS CONTINUE THROUGH MOST OF THE
NIGHT.

WEDNESDAY THROUGH THE END OF THE WEEK...SOME FLURRIES ARE POSSIBLE
AS THE STORM SYSTEM EXITS THE REGION TO OUR SOUTH. WEDNESDAY WILL
BE THE COLDEST DAY OF THE WEEK WITH HIGHS STRUGGLING TO REACH THE
LOW TO MID TEENS. KEPT HIGHS A FEW DEGREES ABOVE MOS...BUT GAMBLING
THAT THE WESTERLY WINDS AND MARCH SUNSHINE WILL RESULT IN
TEMPERATURES A FEW DEGREES HIGHER THAN GUIDANCE.
OTHERWISE...TEMPERATURES MAY BE STUCK IN THE SINGLE DIGITS THROUGH
THE AFTERNOON. EITHER WAY...A WARMING TREND IS EXPECTED FOR THE
REMAINDER OF THE WEEK AS THE STRONG EASTERN PACIFIC RIDGE EXPANDS
EASTWARD A BIT INTO THE CENTRAL AND SOUTHERN ROCKY MOUNTAINS. DUE
TO POTENTIAL SNOW COVER...DID KEEP TEMPERATURES LOWER THAN MOS
THROUGH THE WEEK...WITH TEMPERATURES ABOVE GUIDANCE BY NEXT
WEEKEND AS MOST OF THE SNOW SHOULD MELT BY THAT TIME. EXPECT HIGHS
TO RETURN TO THE 40S TO AROUND 50 BY FRIDAY AND SATURDAY
AFTERNOON.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH SUNDAY EVENING)
ISSUED AT 231 PM MST SAT FEB 28 2015

MVFR CIGS WILL CONTINUE FOR PORTIONS OF SOUTHEAST WYOMING AND
WESTERN NEBRASKA LATE THIS AFTERNOON AND INTO THIS EVENING DUE TO
LLVL UPSLOPE FLOW. ISOLATE SNOW FLURRIES WILL GENERALLY STAY NEAR
KCYS INTO THIS EVENING...UNTIL LIGHT SNOW DEVELOPS FROM SOUTH TO
NORTH ALONG THE I80 CORRIDOR BY 04Z LATE THIS EVENING. IFR
CONDITIONS AND LIGHT SNOW ARE EXPECTED NEAR KLAR...KCYS...AND
POSSIBLY KSNY AFTER 03Z. THE NORTHWARD EXTENT OF THIS SNOW SHOULD
REMAIN SOUTH OF A LINE FROM KRWL TO KAIA. THIS SNOW SHOULD
DIMINISH IN INTENSITY BY SUNDAY MORNING WITH A RETURN TO MVFR OR
HIGHER CONDITIONS BY THE AFTERNOON.

&&

.FIRE WEATHER...

ISSUED AT 240 AM MST SAT FEB 28 2015

C0LDER THAN NORMAL TEMPERATURES...AMPLE SURFACE MOISTURE FROM
SNOWFALL...AND HIGH RELATIVE HUMIDITIES WILL PRECLUDE FIRE WEATHER
CONCERNS THROUGH NEXT WEEK.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...

WY...NONE.
NE...NONE.

&&

$$

SHORT TERM...SML
LONG TERM...TJT
AVIATION...TJT
FIRE WEATHER...MAJ



000
FXUS65 KRIW 282153
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
253 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../00Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. IFR TO MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z
SUNDAY WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE
WIDESPREAD MOUNTAIN OBSCURATIONS. PARTIAL CLEARING WILL OCCUR ACROSS
THE NORTH 18Z SUNDAY TO 00Z MONDAY.

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. IFR TO MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z
SUNDAY WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE
WIDESPREAD MOUNTAIN OBSCURATIONS. PARTIAL CLEARING WILL OCCUR ACROSS
THE NORTH 18Z SUNDAY TO 00Z MONDAY.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER









000
FXUS65 KRIW 282153
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
253 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../00Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. IFR TO MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z
SUNDAY WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE
WIDESPREAD MOUNTAIN OBSCURATIONS. PARTIAL CLEARING WILL OCCUR ACROSS
THE NORTH 18Z SUNDAY TO 00Z MONDAY.

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. IFR TO MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z
SUNDAY WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE
WIDESPREAD MOUNTAIN OBSCURATIONS. PARTIAL CLEARING WILL OCCUR ACROSS
THE NORTH 18Z SUNDAY TO 00Z MONDAY.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER









000
FXUS65 KRIW 282153
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
253 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../00Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. IFR TO MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z
SUNDAY WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE
WIDESPREAD MOUNTAIN OBSCURATIONS. PARTIAL CLEARING WILL OCCUR ACROSS
THE NORTH 18Z SUNDAY TO 00Z MONDAY.

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. IFR TO MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z
SUNDAY WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE
WIDESPREAD MOUNTAIN OBSCURATIONS. PARTIAL CLEARING WILL OCCUR ACROSS
THE NORTH 18Z SUNDAY TO 00Z MONDAY.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER









000
FXUS65 KRIW 282153
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
253 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../00Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. IFR TO MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z
SUNDAY WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE
WIDESPREAD MOUNTAIN OBSCURATIONS. PARTIAL CLEARING WILL OCCUR ACROSS
THE NORTH 18Z SUNDAY TO 00Z MONDAY.

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. IFR TO MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z
SUNDAY WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE
WIDESPREAD MOUNTAIN OBSCURATIONS. PARTIAL CLEARING WILL OCCUR ACROSS
THE NORTH 18Z SUNDAY TO 00Z MONDAY.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER









000
FXUS65 KRIW 282153
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
253 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../00Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. IFR TO MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z
SUNDAY WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE
WIDESPREAD MOUNTAIN OBSCURATIONS. PARTIAL CLEARING WILL OCCUR ACROSS
THE NORTH 18Z SUNDAY TO 00Z MONDAY.

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. IFR TO MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z
SUNDAY WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE
WIDESPREAD MOUNTAIN OBSCURATIONS. PARTIAL CLEARING WILL OCCUR ACROSS
THE NORTH 18Z SUNDAY TO 00Z MONDAY.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER








000
FXUS65 KRIW 282153
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
253 PM MST SAT FEB 28 2015

.SHORT TERM...TONIGHT THROUGH SUNDAY

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG.  PARTIAL CLEARING WILL OCCUR ACROSS THE
NORTH SUNDAY AFTERNOON.  TEMPERATURES WILL REMAIN ON THE COLD SIDE.
LOCAL SNOWFALL OF AN INCH WITH VERY LOW DENSITY SNOW CAN BE
EXPECTED.

.LONG TERM...SUNDAY NIGHT THROUGH SATURDAY

AN UPPER LOW RACING DOWN THE BACK SIDE OF A TROUGH DIGGING TO OUR
SOUTHWEST WILL FUJIWHARA THE CLOSED UPPER LOW OVER SOUTHERN
CALIFORNIA...WHIPPING IT UP INTO THE FOUR CORNERS AREA. IT WILL
KICK UP SOME MOISTURE ASSOCIATED WITH THAT LOW FURTHER NORTH AND
EAST AS WELL...THIS COULD REACH OUR FAR SOUTHERN BORDER AREA WITH
COLORADO WITH SOME MODELS EVEN SUGGESTING SOME PRECIPITATION AS FAR
NORTH AS THE WIND RIVER RANGE AND CASPER ON MONDAY. SPREAD THE POPS
THAT FAR NORTH AS A RESULT BUT THE HEAVIER PRECIPITATION IS EXPECTED
TO REMAIN SOUTH OF THE FORECAST AREA THROUGH MONDAY AFTERNOON.

THIS DIGGING TROUGH WILL ALSO BE ACCOMPANIED BY A CYCLONICALLY
CURVING JET THAT WILL SERVE TO ENHANCE A SHORT WAVE MOVING IN MONDAY
NIGHT. THIS WAVE IS ASSOCIATED WITH A VERY COLD ARCTIC LOW PRESSURE
SYSTEM MOVING ACROSS CENTRAL CANADA. THIS SOUTHERN PIECE OF THAT
SYSTEM WILL INTERACT WITH THE MOISTURE SUPPLIED BY THE SOUTHERN
STORM...PROVIDING SOME SIGNIFICANT MOISTURE TO WORK WITH FOR THIS
TIME OF YEAR. ADDITIONALLY...THE MODELS ARE SHOWING AN ORGANIZED
BAROCLINIC ZONE WITH THE FRONT AS IT DROPS SOUTH THROUGH THE STATE
MONDAY NIGHT INTO TUESDAY FOLLOWED BY A LONG PERIOD OF UPSLOPE FLOW
FOR AREAS EAST OF THE DIVIDE AS HIGH PRESSURE AT THE SURFACE FILTERS
IN BEHIND THE FRONT. SO THERE WILL BE SEVERAL FEATURES THAT WOULD
SUGGEST SOME AREAS OF SIGNIFICANT SNOW ACCUMULATION WITH THIS
SYSTEM. HOWEVER...IT IS A PRETTY COLD SYSTEM ALOFT SO ONCE THAT
FRONT PASSES BY THE MOISTURE AVAILABLE FOR HEAVY SNOW WILL BE
SQUEEZED OUT AND SHUNTED SOUTH AND EAST. ADDITIONALLY...THERE IS NOT
A LOT OF INSTABILITY ALONG AND BEHIND THE FRONT SO THAT WILL KEEP
MOST OF THE SNOW BANDING AND LOCAL ENHANCEMENTS SOUTH AND WEST OF
THE DIVIDE FOR MONDAY NIGHT INTO TUESDAY.

TUESDAY NIGHT COULD BE A COLD ONE AS WE CLEAR FROM NORTH TO SOUTH.
THERE WILL BE SOME MILDER AIR JUST TO THE EAST IN A HURRY TO MOVE IN
HOWEVER...THIS WILL LIKELY LEAD TO SOME SHARP INVERSIONS AND PATCHY
FOG TUESDAY NIGHT AND WEDNESDAY MORNING BUT GIVEN THE EVER
INCREASING SUN ANGLE AND DEVELOPING LEE SIDE TROUGH ON
WEDNESDAY...THE COLD AIR SHOULD NOT BE TOO STUBBORN WITH AT LEAST
SOME MIXING EXPECTED ON WEDNESDAY IF NOT FULL MIXING BY THURSDAY IN
SOME OF THE SHALLOWER BASINS. AS A RESULT...TEMPERATURES COULD GO
FROM 15 BELOW IN SOME BASINS ON WEDNESDAY MORNING TO HIGHS NEAR 40
ON THURSDAY. THE WARMING TREND CONTINUES INTO FRIDAY AND SATURDAY
WITH NO SIGNIFICANT PRECIPITATION EXPECTED ONCE WE CLEAR OUT ON
TUESDAY.

&&

.AVIATION.../00Z ISSUANCE/

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. IFR TO MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z
SUNDAY WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE
WIDESPREAD MOUNTAIN OBSCURATIONS. PARTIAL CLEARING WILL OCCUR ACROSS
THE NORTH 18Z SUNDAY TO 00Z MONDAY.

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

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW IN THE MID LEVELS WILL CONTINUE TO PRODUCE CONDITIONS
FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO LIGHT SNOW AND LOCAL
FOG. IFR TO MVFR CONDITIONS WILL BE RATHER WIDESPREAD THROUGH 18Z
SUNDAY WITH LOCAL VFR CONDITIONS AT TIMES. THIS WILL CAUSE
WIDESPREAD MOUNTAIN OBSCURATIONS. PARTIAL CLEARING WILL OCCUR ACROSS
THE NORTH 18Z SUNDAY TO 00Z MONDAY.

&&

.FIRE WEATHER...

COLD NORTH NORTHEAST LOW LEVEL FLOW WITH WEAK WEST OVERRUNNING
FLOW...WITH LIMITED MOISTURE IN THE MID LEVELS...WILL CONTINUE TO
PRODUCE CONDITIONS FAVORABLE FOR WIDESPREAD STRATUS...FLURRIES TO
LIGHT SNOW AND LOCAL FOG. THIS WILL ALSO INCREASE STRONG
TEMPERATURE INVERSIONS PRODUCING STRONG THERMAL BELTS...LOW MIXING
HEIGHTS AND GENERALLY POOR SMOKE DISPERSAL.

&&

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

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER









000
FXUS63 KUNR 282111
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
211 PM MST SAT FEB 28 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 205 PM MST SAT FEB 28 2015

UPPER TROUGH STRETCHES ACROSS THE CENTRAL AND WESTERN
STATES...WITH LOW SPINNING OVER CA. NORTHERNMOST WAVE WITHIN THE
TROUGH IS PUSHING THROUGH MT. AXIS OF SURFACE TROUGH HAS PASSED
THROUGH THE WESTERN DAKOTAS. COLDER AIR AND CLOUDS ARE MOVING IN
FROM THE NORTHWEST. TEMPS HAVE RISEN INTO THE LOWER 30S ACROSS SOUTH
CENTRAL SD...BUT THE NORTHWESTERN CWA REMAINS IN THE TEENS.
NORTHWEST WINDS ARE AROUND 20 KTS ACROSS THE WESTERN SD PLAINS.

UPPER WAVE WILL QUICKLY SWEEP THROUGH THE NORTHERN PLAINS TONIGHT AS
CLOSED LOW CONTINUES TO SPIN OVER THE SOUTHWEST US. PRECIPITATION
ASSOCIATED WITH THE SOUTHWEST LOW MAY REACH PARTS OF NORTHEAST WY
AND FAR SOUTHWEST SD TONIGHT...BUT WITH SURFACE HIGH SLIDING INTO
THE REGION...EXPECT MAINLY DRY CONDITIONS. DETERMINISTIC MODELS HAVE
BROUGHT PRECIP FARTHER SOUTH OF THE CWA...BUT THE SREF CONTINUES TO
SHOW SOME SLIGHT CHANCE POPS. DID KEEP SLIGHTLY HIGHER POPS OVER THE
SOUTHERN HILLS/CONVERGENCE ZONE. LOWS TONIGHT WILL BE IN THE
SINGLE DIGITS.

UPPER FLOW BECOMES MORE NORTHWESTERLY ON SUNDAY AND SURFACE HIGH
CONTINUES TO PUSH INTO THE REGION. PRESSURE GRADIENT TIGHTENS A BIT
OVER NORTHWEST SD BY MIDDAY SO EXPECT SOME BREEZY WINDS ACROSS THE
WESTERN SD PLAINS. ADDED A FEW UPSLOPE SNOW SHOWERS OVER THE
NORTHERN HILLS AS FROUDE NUMBER SHOOTS UP IN THE AFTERNOON.
ELSEWHERE...SKIES WILL BE MOSTLY SUNNY. HIGHS WILL BE IN THE 20S TO
LOWER 30S. UNDER MOSTLY CLEAR SKIES...LOWS WILL BE IN THE SINGLE
DIGITS TO LOWER TEENS.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 205 PM MST SAT FEB 28 2015

MONDAY WILL FEATURE A BRIEF WARM UP ACROSS THE CWA AS SURFACE WINDS
SWITCH FROM NW TO THE SOUTH AND UPPER LEVEL FLOW TURNS MORE
WESTERLY. AN ARCTIC FRONT WILL COME CRASHING INTO THE CWA BY MONDAY
EVENING...BRINGING STRONG NORTHWESTERLY WINDS...BITTERLY COLD
TEMPERATURES...AND LIGHT ACCUMULATIONS OF SNOW. TEMPERATURES
DURING THE DAY TUESDAY WILL STRUGGLE TO RISE AS STRONG CAA TAKES
PLACE.

THE COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP IS
EXPECTED. THIS NEXT WARM UP... HOWEVER... LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE WELL ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING
ISSUED AT 205 PM MST SAT FEB 28 2015

MVFR CIGS WILL REMAIN ACROSS NORTHEAST WYOMING AND FAR WESTERN SOUTH
DAKOTA THROUGH THIS EVENING...WITH LCL IFR CIGS AROUND THE BLACK
HILLS. ISOLATED SNOW SHOWERS ARE ALSO POSSIBLE ACROSS NORTHEAST
WYOMING INTO THE BLACK HILLS...WITH MVFR/LCL IFR VSBY.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...MCKEMY
AVIATION...7






000
FXUS63 KUNR 282111
AFDUNR

AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
211 PM MST SAT FEB 28 2015

.SHORT TERM...THIS EVENING THROUGH SUNDAY NIGHT
ISSUED AT 205 PM MST SAT FEB 28 2015

UPPER TROUGH STRETCHES ACROSS THE CENTRAL AND WESTERN
STATES...WITH LOW SPINNING OVER CA. NORTHERNMOST WAVE WITHIN THE
TROUGH IS PUSHING THROUGH MT. AXIS OF SURFACE TROUGH HAS PASSED
THROUGH THE WESTERN DAKOTAS. COLDER AIR AND CLOUDS ARE MOVING IN
FROM THE NORTHWEST. TEMPS HAVE RISEN INTO THE LOWER 30S ACROSS SOUTH
CENTRAL SD...BUT THE NORTHWESTERN CWA REMAINS IN THE TEENS.
NORTHWEST WINDS ARE AROUND 20 KTS ACROSS THE WESTERN SD PLAINS.

UPPER WAVE WILL QUICKLY SWEEP THROUGH THE NORTHERN PLAINS TONIGHT AS
CLOSED LOW CONTINUES TO SPIN OVER THE SOUTHWEST US. PRECIPITATION
ASSOCIATED WITH THE SOUTHWEST LOW MAY REACH PARTS OF NORTHEAST WY
AND FAR SOUTHWEST SD TONIGHT...BUT WITH SURFACE HIGH SLIDING INTO
THE REGION...EXPECT MAINLY DRY CONDITIONS. DETERMINISTIC MODELS HAVE
BROUGHT PRECIP FARTHER SOUTH OF THE CWA...BUT THE SREF CONTINUES TO
SHOW SOME SLIGHT CHANCE POPS. DID KEEP SLIGHTLY HIGHER POPS OVER THE
SOUTHERN HILLS/CONVERGENCE ZONE. LOWS TONIGHT WILL BE IN THE
SINGLE DIGITS.

UPPER FLOW BECOMES MORE NORTHWESTERLY ON SUNDAY AND SURFACE HIGH
CONTINUES TO PUSH INTO THE REGION. PRESSURE GRADIENT TIGHTENS A BIT
OVER NORTHWEST SD BY MIDDAY SO EXPECT SOME BREEZY WINDS ACROSS THE
WESTERN SD PLAINS. ADDED A FEW UPSLOPE SNOW SHOWERS OVER THE
NORTHERN HILLS AS FROUDE NUMBER SHOOTS UP IN THE AFTERNOON.
ELSEWHERE...SKIES WILL BE MOSTLY SUNNY. HIGHS WILL BE IN THE 20S TO
LOWER 30S. UNDER MOSTLY CLEAR SKIES...LOWS WILL BE IN THE SINGLE
DIGITS TO LOWER TEENS.

.LONG TERM...MONDAY THROUGH SATURDAY
ISSUED AT 205 PM MST SAT FEB 28 2015

MONDAY WILL FEATURE A BRIEF WARM UP ACROSS THE CWA AS SURFACE WINDS
SWITCH FROM NW TO THE SOUTH AND UPPER LEVEL FLOW TURNS MORE
WESTERLY. AN ARCTIC FRONT WILL COME CRASHING INTO THE CWA BY MONDAY
EVENING...BRINGING STRONG NORTHWESTERLY WINDS...BITTERLY COLD
TEMPERATURES...AND LIGHT ACCUMULATIONS OF SNOW. TEMPERATURES
DURING THE DAY TUESDAY WILL STRUGGLE TO RISE AS STRONG CAA TAKES
PLACE.

THE COLD WILL LAST THROUGH WEDNESDAY BEFORE ANOTHER WARM UP IS
EXPECTED. THIS NEXT WARM UP... HOWEVER... LOOKS TO BE FAIRLY LONG
LIVED AND DRY. THE GFS AND ECMWF HAVE BEEN SHOWING A VERY STRONG
RIDGE BUILDING INTO THE WESTERN US BY MIDWEEK AND PERSISTING WELL
BEYOND THE END OF THE FORECAST PERIOD. EXPECT HIGHS DURING THAT
PERIOD TO BE WELL ABOVE CLIMATOLOGY FOR THIS TIME OF YEAR.

&&

.AVIATION...FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING
ISSUED AT 205 PM MST SAT FEB 28 2015

MVFR CIGS WILL REMAIN ACROSS NORTHEAST WYOMING AND FAR WESTERN SOUTH
DAKOTA THROUGH THIS EVENING...WITH LCL IFR CIGS AROUND THE BLACK
HILLS. ISOLATED SNOW SHOWERS ARE ALSO POSSIBLE ACROSS NORTHEAST
WYOMING INTO THE BLACK HILLS...WITH MVFR/LCL IFR VSBY.

&&

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

$$

SHORT TERM...POJORLIE
LONG TERM...MCKEMY
AVIATION...7







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