975
FXUS65 KCYS 171009
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
309 AM MST TUE DEC 17 2024
KEY MESSAGES
- A WINTER STORM WARNING IS IN EFFECT UNTIL 8 PM TONIGHT FOR THE SNOWY
RANGE, WITH A WINTER WEATHER ADVISORY UNTIL 8 PM TONIGHT FOR
THE SIERRA MADRE RANGE. A HIGH WIND WARNING WILL CONTINUE
UNTIL 11 AM TODAY FOR WIND PRONE LOCATIONS OF SOUTHEAST
WYOMING.
- ANOTHER HIGH WIND EVENT IS LOOKING LIKELY FOR LATE TUESDAY
NIGHT THROUGH LATE WEDNESDAY NIGHT FOR ARLINGTON, BORDEAUX,
THE I-80 SUMMIT AND FOOTHILLS AND FOR NORTHERN CARBON COUNTY.
- RELATIVELY MILD AND DRY WEATHER WILL CONTINUE FOR THURSDAY
THROUGH THE WEEKEND.
SHORT TERM /THROUGH WEDNESDAY NIGHT/
ISSUED AT 123 AM MST TUE DEC 17 2024
TODAY...AN INCOMING SHORTWAVE TROUGH AND OROGRAPHIC SNOWS LOOK ON
TRACK PER THE MODELS, AND WITH QPF LOOKING A BIT HIGHER FROM WPC AND
THE MODELS, WE EXPECT SOME HIGHER SNOWFALL AMOUNTS FOR THE SNOWY
RANGE SO WE HAVE UPGRADED TO A WINTER STORM WARNING THERE FOR 12 TO
15 INCHES TOTAL. LESSER SNOWFALL TOTALS EXPECTED FOR THE SIERRA
MADRE RANGE WITH 5 TO 10 INCHES TOTAL ACCUMULATION.
AS FAR AS WINDS GO, PEAK WINDS SHOULD DECREASE THIS MORNING AS THE
CRAIG TO CASPER 850/700 MB HEIGHT DIFFERENCES DECREASE FROM 54/50
METERS AT 12Z TO 26/36 METERS AT 18Z, THUS THE 11 AM ENDING OF THE
HIGH WIND WARNING LOOKS ON TRACK. OVERALL, IT WILL BE A BREEZY TO
WINDY AFTERNOON WITH NEAR SEASONABLE TEMPERATURES.
TONIGHT...ANOTHER HIGH WIND EVENT LOOKS MORE LIKELY LATE TONIGHT
UNDER STRONG NORTHWEST FLOW ALOFT. CRAIG TO CASPER 850/700 MB HEIGHT
DIFFERENCES INCREASE TO 73/57 METERS BY 12Z WITH OUR LOCAL HIGH WIND
MODEL SUGGESTING WINDS INCREASING AFTER MIDNIGHT, THUS WE HAVE
ISSUED A HIGH WIND WATCH FOR OUR WIND PRONE LOCATIONS STARTING AT 2
AM, INCLUDING ARLINGTON, BORDEAUX, THE I-80 SUMMIT AND FOOTHILLS AND
NORTHERN CARBON COUNTY.
WEDNESDAY...NORTHWEST FLOW ALOFT STRENGTHENS EVEN FURTHER WITH THE
CRAIG-CASPER 850/700 MB HEIGHT DIFFERENCES INCREASING TO 87/67
METERS BY 00Z AND 700 MB WINDS NEAR 50 KNOTS WITH LOCAL HIGH WIND
MODELS SUGGESTING WINDS EXCEEDING HIGH WIND CRITERIA FOR OUR WIND
PRONE LOCATIONS, AND POSSIBLY NEARBY LOCATIONS. THUS WINDS EXPECTED
TO RAMP UP EVEN MORE FOR OUR WIND PRONE LOCATIONS AND THE HIGH WIND
WATCH CONTINUES. TEMPERATURES WILL BE WARMER WITH 700 MB
TEMPERATURES NEAR 2 CELSIUS.
WEDNESDAY NIGHT...LOW AND MID LEVEL GRADIENTS REMAIN STRONG ALTHOUGH
CRAIG TO CASPER 850/700 MB HEIGHT DIFFERENCES SLOWLY DECREASE TO
64/57 METERS BY 12Z, THUS THE HIGH WIND WATCH CONTINUES FOR OUR WIND
PRONE LOCATIONS. NOT AS COLD AS THE PREVIOUS NIGHT DUE TO EXPECTED
WINDS AND A MODERATING AIRMASS.
LONG TERM /THURSDAY THROUGH MONDAY/
ISSUED AT 123 AM MST TUE DEC 17 2024
DETERMINISTIC/ENSEMBLE MODELS ARE ALL DEPICTING THE UPPER LEVEL
SHORTWAVE MOVING INTO THE NORTHERN PLAINS ON THURSDAY.
FOLLOWING IN ITS TRACKS THE WPC CLUSTERS AND VARIOUS ENSEMBLES
ARE SHOWING AN UPPER LEVEL RIDGE BUILDING OVER THE CENTRAL AND
NORTHERN ROCKIES. THIS WILL CAUSE THE PRESSURE/HEIGHT GRADIENTS
TO SLACKEN DURING THE COURSE OF THE DAY ON THURSDAY. EVEN WITH
THE GRADIENTS WEAKENING WE MAY CONTINUE TO BE QUITE WINDY OVER
THE WIND PRONE AREAS ON THURSDAY MORNING, BUT THIS SHOULD NOT
LAST TOO LONG AS THE UPPER LEVEL RIDGE BUILDS INTO THE AREA.
THE REMAINDER OF THE WEEKEND IS LOOKING QUITE MILD WITH NAEFS
SHOWING TEMPERATURES AROUND ONE STANDARD DEVIATION ABOVE NORMAL
FOR THIS TIME OF YEAR. THIS ALSO AGREES WITH THE WPC CLUSTERS
WITH ALL FOUR CLUSTERS SHOWING THE ANOMALOUS UPPER LEVEL RIDGE
IN PLACE. AT THIS POINT, IT LOOKS LIKE A GOOD WEEKEND TO BE
OUTDOORS ESPECIALLY IN THE LOWER ELEVATIONS EAST OF THE I-25
CORRIDOR WHERE AFTERNOON HIGHS COULD REACH THE MID TO UPPER
50S.
THERE IS LITTLE MORE UNCERTAINTY EARLY NEXT WEEK ON HOW THE
PATTERN WILL EVOLVE. THERE IS A CHANCE THAT THE RIDGE MAY BREAK
DOWN A BIT. WE WILL ALSO NEED TO KEEP AN EYE ON THE TRACK OF A
CLOSED LOW MOVING TOWARDS THE CALIFORNIA COASTLINE EARLY NEXT
WEEK. AT THIS POINT IT IS TOO EARLY TO SAY WHETHER THIS CLOSED
LOW WILL HAVE ANY IMPACTS TO OUR REGION. STAY TUNED!
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1005 PM MST MON DEC 16 2024
CONFIDENCE GROWING THAT WE WILL SEE A LIGHT SNOW EVENT AT KRWL
AND KLAR STARTING EARLY TUESDAY MORNING AND POSSIBLE PERSISTING
THROUGH THE AFTERNOON. CONTINUED MVFR TO IFR CONDITIONS AT BOTH
AIRPORTS TO REFLECT THIS INCREASED CONFIDENCE. A COLD FRONT
APPROACHING FROM THE NORTH EXPECTED TO BRING SNOW TO CARBON AND
ALBANY COUNTIES THAT COULD LIMIT FLIGHT CONDITIONS FOR THESE TWO
AIRPORTS. LOOKING AT FAIRLY WIDESPREAD SNOW AS EARLY AS 10Z FOR
KRWL AND A LITTLE LATER FOR KLAR. VFR ELSEWHERE. WILL CONTINUE
TO MONITOR TAFS THIS EVENING AND TRY TO GET BETTER TIMING FOR
THE 12Z TAFS.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HIGH WIND WARNING UNTIL 11 AM MST THIS MORNING FOR WYZ104-106-
110.
HIGH WIND WATCH FROM LATE TONIGHT THROUGH LATE WEDNESDAY NIGHT
FOR WYZ104-106-110-116-117.
WINTER WEATHER ADVISORY UNTIL 8 PM MST THIS EVENING FOR WYZ112.
WINTER STORM WARNING UNTIL 8 PM MST THIS EVENING FOR WYZ114.
NE...NONE.
SHORT TERM...RUBIN
LONG TERM...REC
AVIATION...GCC
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