252
FXUS65 KCYS 140936
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
236 AM MST SUN DEC 14 2025
KEY MESSAGES
- A FEW FLURRIES POSSIBLE ACROSS THE NEBRASKA PANHANDLE THIS
AFTERNOON AS AN ARCTIC FRONT SURGES SOUTH CRASHING TEMPS INTO
THE TEENS AND 20S TONIGHT.
- WARMING TREND EXPECTED SUNDAY THROUGH EARLY NEXT WEEK WITH
STRONG WINDS RETURNING TO SOUTHEAST WYOMING TUESDAY THROUGH
THURSDAY
SHORT TERM /THROUGH MONDAY NIGHT/
ISSUED AT 225 AM MST SUN DEC 14 2025
LESS ACTIVE EARLY THIS MORNING COMPARED TO YESTERDAY AS WINDS
HAVE DIMINISHED SUBSTANTIALLY. ARCTIC COLD FRONT STILL REMAINS
OVER THE AREA AS A STATIONARY FRONT, POSITIONED JUST WEST OF THE
INTERSTATE 25 CORRIDOR NEAR THE LARAMIE RANGE. TEMPERATURES ARE
IN THE TEENS AND UPPER SINGLE DIGITS WELL TO THE EAST OF THE
FRONT INCLUDING FAR EASTERN WYOMING AND MOST OF WESTERN
NEBRASKA...WITH 20S NEAR THE STATIONARY FRONT. FURTHER WEST,
TEMPERATURES REMAINS IN THE 30S TO LOW 40S. SOME PATCHY FOG AND
LOW CLOUDS HAVE BEEN OBSERVED ACROSS THE CENTRAL AND SOUTHERN
NEBRASKA PANHANDLE...MAINLY IMPACTING BOX BUTTE, MORRILL, AND
CHEYENNE COUNTIES WITH VISIBILITY BELOW 1 MILE AT TIMES. DO NOT
EXPECT THIS FOG TO LAST TOO LONG THIS MORNING, SO NOT EXPECTING
TO ISSUE A DENSE FOG OR FREEZING FOG ADVISORY. FOG SHOULD LIFT
AROUND SUNRISE AS THE ARCTIC FRONT BEGINS TO RETREAT EASTWARD.
ALL MODELS IN GOOD AGREEMENT FOR TODAY AND MONDAY AND SHOW
PLEASANT AND BENIGN WEATHER FOR MID DECEMBER. MODELS AND ALL
ENSEMBLE GUIDANCE SHOW THE ARCTIC COLD FRONT RETREATING
EASTWARD SLOWLY BY LATE THIS MORNING AND INTO THIS AFTERNOON.
MODELS HAVE TRENDED A BIT SLOWER WITH MOVEMENT OF THE STATIONARY
FRONT, SO LOWERED HIGH TEMPERATURES ACROSS PORTIONS OF THE
NEBRASKA PANHANDLE TO REFLECT THIS TREND. FURTHER WEST, EXPECT
HIGHS IN THE MID 50S TO LOW 60S ACROSS SOUTHEAST WYOMING AND FAR
WESTERN NEBRASKA. THIS WILL RESULT IN A PRETTY NICE DAY WITH
RELATIVELY LIGHT WINDS. SIMILAR WEATHER EXPECTED FOR MONDAY AS
700MB TEMPERATURES REMAIN BETWEEN 3C TO 7C...RESULTING IN
AFTERNOON HIGHS A FEW DEGREES WARMER COMPARED TO TODAY. WINDS
WILL START TO INCREASE OVER THE WIND PRONE AREAS OF SOUTHEAST
WYOMING EARLY MONDAY MORNING, BUT HIGH WIND CRITERIA IS NOT
EXPECTED AT THIS TIME.
FOR MONDAY NIGHT, LOW TO MIDLEVEL PRESSURE GRADIENT BEGINS TO
INCREASE AHEAD OF THE NEXT PACIFIC SYSTEM, FORECAST TO IMPACT
WYOMING AS EARLY AS TUESDAY...BUT MOSTLY ON WEDNESDAY. 700MB
WINDS WILL CLIMB ABOVE 50 KNOTS LATER IN THE PERIOD TOWARDS DAY
BREAK ON TUESDAY. INCREASED WINDS USING IN-HOUSE WIND GUIDANCE
AS A TEMPLATE. LOW LEVEL SUBSIDENCE IS EXPECTED TO BE DELAYED BY
SEVERAL HOURS WITH THIS EVENT, WITH SUBSIDENCE PEAKING CLOSER TO
TUESDAY MORNING...EVEN THOUGH 700MB WINDS CLIMB ABOVE 50 KNOTS
AFTER MIDNIGHT MONDAY NIGHT. SINCE THIS EVENT IS STILL 48+ HOURS
OUT, WILL NOT ISSUE ANY HIGH WIND HEADLINES QUITE YET DUE TO THE
SUBTLE TIMING DIFFERENCES DISCUSSED ABOVE. DID INCREASE WIND
GUSTS ABOVE CRITERIA AND WILL LIKELY NEED A HIGH WIND WATCH
SHORTLY. THIS WIND EVENT LOOKS LIKE IT WILL MAINLY IMPACT THE
WIND PRONE AREAS TO START OFF, WITH WINDY CONDITIONS EXPECTED IN
THE HIGH VALLEYS AND THE EASTERN HIGH PLAINS.
LONG TERM /TUESDAY THROUGH SATURDAY/
ISSUED AT 235 AM MST SUN DEC 14 2025
LONG RANGE FORECAST GENERALLY ON TRACK, MADE A FEW TWEAKS TO
WINDS AND TEMPERATURES AS WE HEAD INTO WEDNESDAY THROUGH LATE IN
THE WEEK. IN-HOUSE WIND GUIDANCE CONTINUES TO SHOW A FEW MORE
WIND EVENTS...WITH A SECOND ONE ON WEDNESDAY AND WEDNESDAY
NIGHT, AND POSSIBLY A THIRD STARTING THURSDAY NIGHT. THE THIRD
EVENT THURSDAY NIGHT/FRIDAY MAY BECOME MORE WIDESPREAD OVER
SOUTHEAST WYOMING WITH THE 00Z GFS SHOWING 85+ KNOT WINDS NEAR
THE LARAMIE RANGE AND APPARENT MOUNTAIN WAVE ACTIVITY LIKELY
EXTENDING EASTWARD INTO THE WESTERN NEBRASKA PANHANDLE. OTHER
MODELS AREN'T QUITE AS STRONG, BUT STILL SHOW A SOLID 70+ KNOTS.
CONFIDENCE IS LIMITED OF COURSE SINCE IT IS STILL 5 DAYS OUT,
BUT THE HIGH WIND SIGNAL IS SHOWING UP IN THE 25TH TO 75TH
INTERQUARTILE SPREAD OF THE GRAND ENSEMBLE.
INCREASED POP WEDNESDAY AND WEDNESDAY NIGHT AS THE PACIFIC
TROUGH MOVES THROUGH THE REGION. SEEMS TO BE ENOUGH FORCING
ALONG THE PACIFIC COLD FRONT FOR RAIN AND SNOW EVEN IN THE LOWER
ELEVATIONS. INCREASED POP A BIT TO REFLECT THIS TREND.
PREVIOUS LONG TERM DISCUSSION...
ISSUED AT 111 PM MST SAT DEC 13 2025
FOR THE LONGER TERM THINGS MAY NOT BE AS ZONAL ALOFT AS ONCE
THOUGHT WITH MULTIPLE SHORTWAVES LIKELY TO TRAVERSE THE CREST OF
THE FLATTENED RIDGE. THURSDAY THEN LOOKS TO BRING A MUCH MORE
AMPLIFIED AND IMPRESSIVE WAVE TO THE NORTHERN ROCKIES WITH A
700MB JET CROSSING RIGHT THROUGH THE SOUTHEAST WYOMING PLATEAU
AND MOUNTAIN GAP AREAS. GUIDANCE MUCH MORE HEAVILY FAVORS THIS
SYSTEM TO BRING HIGH WINDS TO THE REGION WITH GREATER THAN A 70%
CONFIDENCE FROM THE RANDOM FOREST MODEL THAT THIS WILL MEET
HIGH WIND WARNING CRITERIA WHICH IS AN IMPRESSIVE SIGNAL FOR
SOMETHING 5-6 DAYS OUT. ALONG WITH THE VERY LIKELY HIGH WINDS,
THIS SYSTEM SHOULD ALSO BRING MOISTURE TO THE WEST WITH SOME
HIGH ELEVATION SNOW. HOWEVER WITH IT FALLING OVER A MULTI DAY
PERIOD IT WOULD BE UNLIKELY TO MEET ADVISORY CRITERIA.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1020 PM MST SAT DEC 13 2025
LIFR CIGS HAVE NOT SCOURED OUT YET FOR KSNY, EXPECT THESE TO HOLD
FIRM INTO THE MORNING HOURS, AND THERE MAY OCCASIONALLY BE A
REDUCTION OF VIS DUE TO BR. THIS CLOUD DECK IS IN THE VC OF KAIA, SO
THERE IS A POSSIBILITY OF LOW CIGS OVER THE NEXT SEVERAL HOURS AND
AS SUCH, A TEMPO GROUP WAS ADDED FOR CIGS OF 400 FEET. OTHERWISE, NO
AVIATION WEATHER CONCERNS FOR ALL THE REMAINING TERMINALS AS VFR
CONDITIONS WILL PREVAIL FOR THIS TAF PERIOD. WINDS WILL BECOME
GUSTY AROUND 19Z SUNDAY, NO WHERE NEAR AS STRONG AS DAYS PRIOR.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...TJT
LONG TERM...TTX2
AVIATION...RZ
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