599
FXUS65 KCYS 201139
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
439 AM MST SAT DEC 20 2025
KEY MESSAGES
- HIGH WINDS CONTINUE THIS MORNING BUT SHOULD FINALLY RELAX
DURING THE LATE EVENING THROUGH EARLY AFTERNOON HOURS.
- WINTER WEATHER ADVISORIES ARE IN EFFECT FOR THE SNOWY AND
SIERRA-MADRE RANGES DUE TO MODERATE AMOUNTS OF MOUNTAIN
SNOWFALL THROUGH THIS EVENING.
- WHILE WINDY CONDITIONS MAY RETURN BEGINNING SUNDAY THROUGH
MONDAY AND ONCE AGAIN ON CHRISTMAS DAY, THE BULK OF THE
STRONGER ACTIVITY SHOULD REMAIN RELEGATED TO OUR USUAL WIND
PRONE LOCATIONS.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED AT 210 AM MST SAT DEC 20 2025
NOW THAT WE'RE ON THE BACKSIDE OF THE STRONG WIND EVENT, A
CALMER FORECAST IS IN STORE FOR THE SHORT TERM, EVEN IF IT DOES
LEAD TO ANOTHER ROUND OF STRONGER WINDS BY THE END OF THE
PERIOD. AT THE UPPER LEVELS, A STRONG TROUGH THAT HELPED SPUR
THIS EVENT WILL CONTINUE ITS PATH EASTWARDS ACROSS SOUTHERN
CANADA AND THE NORTHERN US, WITH RIDGING STARTING TO AMPLIFY
OVER THE CWA INTO SUNDAY, BUT A QUICK SHORTWAVE WILL MOVE ACROSS
THROUGH MONDAY TO HELP PRODUCE ANOTHER ROUND OF DISTURBED
CONDITIONS.
FOR TODAY, HIGH WINDS WILL LINGER THROUGH THE MORNING HOURS,
WITH CONDITIONS FINALLY CALMING INTO THE LATE MORNING AND EARLY
AFTERNOON FOR ALL ZONES. PRECIPITATION SHOULD ALSO LINGER
ACROSS THE CWA THROUGH THE EARLY AFTERNOON, WITH LIGHT RAIN/SNOW
MIX FOR LOWER ELEVATIONS WITH MINIMAL ACCUMULATIONS, AND MODEST
SNOWFALL IN THE HIGH ELEVATIONS WITH A WINTER WEATHER ADVISORY
OUT THROUGH THIS EVENING FOR THE SNOWY AND SIERRA-MADRE RANGES.
THEREAFTER, A CALMER PERIOD WITH WINDS CAN BE EXPECTED THROUGH
SUNDAY MORNING, BUT THE AFOREMENTIONED SHORTWAVE'S APPROACH WILL
FUEL A NEW ROUND OF GUSTY WINDS ON SUNDAY. THE USUAL 700MB JET
SHOULD START TO PEAK BACK UP AROUND THE EVENING HOURS ON SUNDAY
WITH SPEEDS OF 60-70 KNOTS, AND IN HOUSE GUIDANCE SHOWING A GOOD
CONSENSUS ON HIGH WIND LEVEL GUSTS (58+ MPH) BEGINNING SOMETIME
AROUND 18-21Z ON SUNDAY AND PERSISTING THROUGH AROUND 18Z ON
MONDAY. THANKFULLY, THIS WON'T BE NEARLY THE WIDESPREAD EVENT
WE'VE SEEN OVER THE PAST SEVERAL DAYS, AND STRONGER GUSTS WORTHY
OF HIGHLIGHTS WILL BE LIMITED TO OUR USUAL WIND PRONE SPOTS
ACROSS WYOMING. OTHERWISE, BEHIND THE COLD FRONT TODAY LOOK FOR
WARMER THAN NORMAL BUT COOLER OVERALL TEMPERATURES IN THE HIGH
30'S TO 40'S, WITH THE STRENGTHENING RIDGE BRINGING UNSEASONABLE
40'S AND 50'S BACK ON SUNDAY.
LONG TERM /MONDAY THROUGH FRIDAY/
ISSUED AT 210 AM MST SAT DEC 20 2025
THE LONG TERM WILL BE A VERY WARM BUT OTHERWISE FAIRLY BENIGN
PERIOD FOR THE CWA, WITH ANOTHER SHOT OF STRONGER WINDS
POTENTIALLY ON CHRISTMAS DAY. OVERALL THE PATTERN SHOULD BE
MOSTLY SIMPLE AS DEEP UPPER LEVEL RIDGING CONTROLS MUCH OF THE
US FROM IT'S CENTER IN THE SOUTHERN US, BUT A SHORTWAVE ON
THURSDAY INTO FRIDAY BRINGS A QUICK DISRUPTION TO THAT OVERALL
FLOW PATTERN FOR OUR CWA.
WITH THIS COMES CONSISTENT WEATHER THROUGH THE MIDDLE OF THE
WEEK, AS HIGHS STAY UNSEASONABLY WARM AND NEAR RECORD, WITH
TEMPERATURES IN THE 50'S TO 60'S THROUGH WEDNESDAY. THE ONLY
CONCERN THAT WILL BE HIGHLIGHT WORTHY OUTSIDE OF THE WARMTH WILL
BE THE STRONGER WINDS THAT PERSIST FROM SUNDAY INTO MONDAY, BUT
AS THESE WEAKEN ON MONDAY WE'LL SEE SOME BREEZINESS THROUGH THE
MIDDLE OF THE WEEK, BUT NOTHING STRONG ESPECIALLY FOR THIS PART
OF THE COUNTRY. INTO THURSDAY A SHORTWAVE ROUNDS THE PERIPHERY
OF THE RIDGE, AND WHILE THIS FEATURE WILL STRENGTHEN OUR
PRESSURE GRADIENTS AND POTENTIALLY CREATE A NEW ROUND OF WIND
HIGHLIGHTS FOR CHRISTMAS DAY, OVERALL CONCERNS ARE FAIRLY
MINIMAL FROM IT OTHERWISE. IN HOUSE GUIDANCE IS STARTING TO PICK
UP ON THIS FEATURE AND HINTING AT HIGH WINDS FOR OUR WIND PRONE
LOCATIONS, AND MODEL ANALYSIS INDICATES A STRONG 700MB JET
RETURNS WITH SOME OF THAT MIXING DOWN TO THE SURFACE. BUT
MOISTURE FROM THIS FEATURE WILL BE MINIMAL, AND GENERALLY WE
SHOULD ONLY SEE HIGHER ELEVATION RAIN/SNOW MIX AND MOUNTAIN
SNOWFALL OF LIGHT TO MODERATE AMOUNTS. A PERSISTENT
SOUTHWESTERLY FLOW COULD BRING UPSLOPE SNOWFALL ACCUMULATIONS
IN THE SIERRA-MADRE RANGE NEARING WINTER STORM WARNING LEVELS
(12+ INCHES), BUT THIS WILL BE SPREAD OUT OVER A 48 HOUR PERIOD
AS WELL AND VERY GRADUAL.
BY FRIDAY, TEMPERATURES SHOULD COOL SLIGHTLY AS A FRONT PASSES
ACROSS THE REGION, BUT DON'T EXPECT A QUICK DROP AS WE STILL AIM
FOR HIGHS IN THE 40'S TO 50'S. OVERALL THERE IS HIGH CONFIDENCE
(80-90%) IN THE FORECAST AS ENSEMBLES ARE IN FIRM AGREEMENT ON
THE STRONG RIDGE HOLDING MOST OF THE US HOSTAGE THROUGH
CHRISTMAS. IF YOU WERE HOPING FOR A WHITE CHRISTMAS, THIS IS
YOUR SIGN TO TEMPER YOUR EXPECTATIONS NOW, AS THE BEST THE
REGION CAN OFFER US IS UNSEASONABLE WARMTH AND MORE WIND.
AVIATION /12Z TAFS THROUGH 12Z SUNDAY/
ISSUED AT 436 AM MST SAT DEC 20 2025
CONDITIONS WILL BE A MIX OF FLIGHT CATEGORIES OVER THE NEXT FEW
HOURS FOR MOST SITES AS BANDS OF LIGHT WINTRY PRECIPITATION MAKE
THEIR WAY ACROSS THE AREA, MOSTLY LIGHT SNOW. MVFR TO IFR
POSSIBLE WITH THIS ACTIVITY. ONCE THIS MOVES OUT, VFR CONDITIONS
SHOULD DOMINATE THE REGION AND PERSIST THROUGH THE END OF THE
FORECAST PERIOD. WINDS REMAIN BREEZY FOR WY TERMINALS THROUGH
THE AFTERNOON, BUT SHOULD LESSEN TO AROUND 10-12 KNOTS OR LESS
THIS EVENING AND OVERNIGHT. CIGS WITH THE AFOREMENTIONED
PRECIPITATION WILL BE LOW TO MID LEVEL, WITH MID LEVEL DECKS
STICKING AROUND THROUGH THE MORNING BEFORE LIFTING AND CLEARING
INTO THE AFTERNOON AND OVERNIGHT.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HIGH WIND WARNING UNTIL 11 AM MST THIS MORNING FOR WYZ104-110-
116.
WINTER WEATHER ADVISORY UNTIL 8 PM MST THIS EVENING FOR WYZ112-
114.
NE...NONE.
SHORT TERM...CG
LONG TERM...CG
AVIATION...CG
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