067
FXUS65 KCYS 301146
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
446 AM MST THU JAN 30 2025
KEY MESSAGES
- THERE IS A SLIGHT CHANCE FOR SLUSHY SNOW ACCUMULATIONS IN
CHEYENNE COUNTY THIS MORNING.
- MILD TEMPERATURES CONTINUE INTO SATURDAY FOR AREAS ALONG AND
EAST OF I-25, BUT AREAS TO THE WEST WILL REMAIN COLD,
ESPECIALLY AT NIGHT.
- HIGH WIND WATCH GOES INTO EFFECT TONIGHT FOR THE WIND PRONES
AS STRONG WINDS ARE EXPECTED THROUGH SATURDAY EVENING.
- BETTER MODEL AGREEMENT CONCERNING TEMPERATURES AND THE
PRECIPITATION POTENTIAL FOR SUNDAY ONWARDS.
SHORT TERM /THROUGH FRIDAY NIGHT/
ISSUED AT 402 AM MST THU JAN 30 2025
THE QUIET WEATHER PERIOD IS ENDING AND THE HIGH WIND FESTIVAL LOOKS
TO BEGIN TONIGHT. THE UPPER LEVEL LOW THAT IS EXPECTED TO GIVE THE
SOUTHERN PORTION OF THE NEBRASKA PANHANDLE A CHANCE FOR SNOW IS
SITTING ON THE CO/NM BORDER. IT'S STILL PROJECTED TO TRAVEL
NORTHEAST FROM ITS CURRENT POSITION TO GIVE MAYBE KIMBALL TO SIDNEY
NEBRASKA SOME LIGHT PRECIPITATION BUT LOOKING AT RADAR AND SATELLITE
NOT QUITE CERTAIN IF THAT WILL HAPPEN OR NOT. HOWEVER, I STILL KEPT
20-30 POPS FOR THIS MORNING THROUGH 20Z. THROUGHOUT THE DAY AN AREA
OF HIGH PRESSURE MOVES SOUTHEAST INTO NORTHWEST COLORADO. BY TONIGHT
OR 06Z FRIDAY, THE PRESSURE GRADIENT STARTS TO TIGHTEN (AROUND 6-
10MB DIFFERENCE ACROSS THE WIND PRONES) AND BEGIN OUR POSSIBLY MULTI-
DAY HIGH WIND FESTIVAL. THERE IS ALSO A 700MB JET THAT STARTS TO
DEVELOP ALOFT STARTING AROUND 12Z FRIDAY GRADUALLY INCREASING FROM
50-55KTS TO 60-70KTS BY 03Z SATURDAY. THE CRAIG TO CASPER 850MB
GRADIENT IS ALSO AROUND 70 TO 75 METERS. WITH 60 TO 80 PERCENT
PROBABILITIES OF REACHING HIGH WIND CRITERIA FROM OUR IN HOUSE
MACHINE LEARNING ALGORITHM. GIVEN THAT THE GFS AND NAM OMEGA FIELDS
DEPICT A MOUNTAIN WAVE SETUP A HIGH WIND WATCH WAS ISSUED FOR
ARLINGTON, BORDEAUX, MUDDY GAP, AND THE I-80 SUMMIT AND FOOTHILLS
AREAS. WHILE CONFIDENCE IS THERE THAT THE HIGH WIND FESTIVAL WILL
HAPPEN THERES A LITTLE UNCERTAINTY WITH THE INITIATION TIMING OF THE
HIGH WINDS. THE HIGH WIND WATCH ALSO CANCELS AT 00Z SUNDAY WHEN THE
HEIGHT GRADIENTS DROP BELOW 40 METERS AND THE 700MB JET DIES DOWN.
HOWEVER, THE GFS AND NAM OMEGA FIELDS SHOW MAXED OUT SUBSIDENT FLOW
INDICATING THERE STILL COULD BE MOUNTAIN WAVE ACTIVITY TO SUSTAIN
THIS WIND FESTIVAL FURTHER. FRIDAY INTO THIS WEEKEND, THE UPPER
LEVEL PATTERN SWITCHES TO A FLAT ZONAL PATTERN WITH INCREASING
CHANCES FOR PRECIPITATION AND MORE HEADLINES THIS WEEKEND.
LONG TERM /SATURDAY THROUGH WEDNESDAY/
ISSUED AT 402 AM MST THU JAN 30 2025
LITTLE CHANGE MADE TO THE LONG TERM AS ZONAL FLOW IS STILL EXPECTED
TO DOMINATE CONUS THIS WEEKEND AND INTO NEXT WEEK. MODELS HAVE COME
INTO BETTER AGREEMENT REGARDING PLACEMENT OF THE 250 MB JET WHICH
HAS LEAD TO AN INCREASE IN CONFIDENCE FOR THE FORECAST. BOTH THE GFS
AND ECMWF PLACE THE MAIN JET STREAK IN NORTHERN WYOMING. THIS ALLOWS
FOR GREATER CERTAINTY IN THE WIND, PRECIPITATION, AND TEMPERATURE
FORECAST IN THE LONG TERM.
BY SATURDAY, THE CWA WILL ALREADY BE IN THE MIDST OF A HIGH WIND
EVENT, WITH HIGH WIND WATCHES ALREADY IN PLACE FOR THE WIND PRONE
AREAS THROUGH SATURDAY AFTERNOON. WHILE IT APPEARS WINDS IN THE WIND
PRONE AREAS MAY PEAK LATE FRIDAY NIGHT, HIGH WINDS COULD SPILL OVER
INTO WIND PRONE ADJACENT AREAS DURING THE DAY SATURDAY. A SURGE OF
50 TO 60 KT WINDS ALOFT WILL PUSH INTO EASTERN WYOMING AND EVEN INTO
THE NEBRASKA PANHANDLE. SUBSIDENCE SUPPORTS THESE WINDS
POTENTIALLY MAKING IT DOWN TO THE SURFACE IN EASTERN WYOMING
AND EVEN IN THE NEBRASKA PANHANDLE. THIS WILL BE SOMETHING TO
MONITOR IN THE COMING SHIFTS AS HIGH WIND WATCHES MAY NEED TO BE
EXPANDED. HIGH WINDS IN THE WIND PRONE AREAS ALSO LOOK SOLID
DURING THIS TIME. 60 KT WINDS ALOFT WITH GREAT SUBSIDENCE SHOULD
BRING THESE WINDS DOWN TO THE SURFACE. CAG-CPR 700 MB GRADIENTS
ALSO SUPPORT HIGH WINDS, WITH IN- HOUSE GUIDANCE ALSO
SUGGESTING HIGH WINDS DURING THE DAY SATURDAY. IT IS POSSIBLE
THAT AFTER A BRIEF LULL, HIGH WINDS COULD BE BACK AS SOON AS
SATURDAY NIGHT. ALTHOUGH IN-HOUSE GUIDANCE IS NOT TOTALLY
CAPTURING IT JUST YET, THE GFS DOES SHOW 55 TO 60 KT WINDS ALOFT
WITH GOOD SUBSIDENCE. CAG-CPR 700 MB HEIGHT GRADIENTS ALSO
REMAIN ELEVATED SATURDAY NIGHT. IN THE CURRENT FLOW PATTERN,
HIGH WINDS COULD BE POSSIBLE ACROSS THE SOUTHEAST WYOMING WIND
PRONES THROUGH MONDAY.
THE GFS AND ECMWF HAVE COME INTO BETTER AGREEMENT REGARDING
PRECIPITATION, ALBEIT THE GFS STILL PORTRAYS A WETTER SOLUTION.
REGARDLESS, BOTH SHOW A PROLONGED MOUNTAIN SNOW EVENT AS MID-LEVEL
MOISTURE IS ESSENTIALLY FUNNELED IN FROM THE PACIFIC. WEST TO
SOUTHWEST FLOW WILL SET THE STAGE FOR A PROLIFIC OROGRAPHIC SNOW
EVENT FOR THE SIERRA MADRES. THIS ZONE WILL LIKELY BE THE BIG WINNER
AND SEE THE HIGHEST SNOWFALL TOTALS AFTER ALL IS SAID AND DONE. A
COUPLE FEET OF SNOW COULD BE POSSIBLE HERE AND THE SNOWYS THIS
WEEKEND AND INTO NEXT WEEK. PRECIPITATION WILL LIKELY SPREAD INTO
THE PLAINS BY SUNDAY EVENING AND LINGER THROUGH MID-WEEK. MODELS ARE
IN FAIRLY GOOD AGREEMENT KEEPING MOST OF THE PRECIPITATION CONFINED
TO THE NORTHERN ZONES OF THE CWA, CLOSER TO THE 250 MB JET. SNOW
ACCUMULATIONS COULD BE POSSIBLE SUNDAY NIGHT, SO THIS WILL BE
SOMETHING TO KEEP AN EYE ON.
TEMPERATURES OVER THE WEEKEND WILL BE ON THE MILD SIDE, ESPECIALLY
SATURDAY. DOWNSLOPING WINDS AND 700 MB TEMPERATURES NEAR 0C WILL
MAKE FOR A FAIRLY WARM DAY WITH TEMPERATURES IN THE 50S FOR MANY
LOCATIONS EAST OF THE LARAMIE RANGE. FROM HERE, IT IS POSSIBLE THAT
TEMPERATURES WILL GRADUALLY GET COOLER THROUGH MID-WEEK. HOWEVER,
THIS IS WHERE THE ECMWF AND THE GFS DIFFER. THE GFS GRADUALLY USHERS
IN COOLER TEMPERATURES AS IT PUSHES A STATIONARY BOUNDARY FURTHER
SOUTH THROUGH THE WEEK. THE ECMWF SOLUTION IS ACTUALLY LIKELY TO
INCREASE TEMPERATURES THROUGH MID-WEEK AS WEAK RIDGING OVER THE
ROCKIES PUSHES THE STATIONARY BOUNDARY FURTHER NORTH ALLOWING WARMER
700 MB AIR INTO THE CWA. FOR NOW, DECIDED TO TREND TEMPERATURES
DOWNWARD THROUGHOUT THE WEEK, BUT NOT AS AGGRESSIVELY AS SOME
MODELS.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 445 AM MST THU JAN 30 2025
MINIMAL AVIATION IMPACTS ARE EXPECTED TODAY. MOSTLY CLEAR SKIES AND
LIGHT WINDS CAN BE EXPECTED AT MOST TERMINALS DURING THE DAY TODAY.
KSNY COULD SEE SOME WRAP AROUND SHOWER ACTIVITY FROM A STORM SYSTEM
IN COLORADO TODAY. CANNOT RULE OUT MVFR CIGS AS WELL AS LIGHT
SNOW AND VISIBILITY DROPS DOWN TO IFR. SHOWER ACTIVITY WILL
CLEAR OUT BY THIS EVENING, LEADING TO A QUIET OVERNIGHT.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HIGH WIND WATCH FROM FRIDAY MORNING THROUGH SATURDAY AFTERNOON
FOR WYZ104.
HIGH WIND WATCH FROM LATE TONIGHT THROUGH SATURDAY AFTERNOON
FOR WYZ106-110.
HIGH WIND WATCH FROM FRIDAY AFTERNOON THROUGH SATURDAY
AFTERNOON FOR WYZ116-117.
NE...NONE.
SHORT TERM...MM
LONG TERM...SF
AVIATION...SF
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