130
FXUS65 KCYS 202031
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
131 PM MST SAT DEC 20 2025
KEY MESSAGES
- WINTER WEATHER ADVISORIES ARE STILL IN EFFECT FOR THE SNOWY
AND SIERRA-MADRE RANGES DUE TO ADDITIONAL MODERATE SNOWFALL
THROUGH THIS EVENING.
- WINDY CONDITIONS LOOK TO RETURN BY SUNDAY AFTERNOON FOR THE
KNOWN WINDIER PRONE LOCATIONS THROUGH MOST OF MONDAY.
- WHAT ABOUT CHRISTMAS DAY, WINDIER CONDITIONS ARE POSSIBLE ONCE
AGAIN, ESPECIALLY IN THE WIND PRONE LOCATIONS.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED AT 131 PM MST SAT DEC 20 2025
WHAT A DIFFERENCE A DAY MAKES! THAT GLORIOUS COLD FRONT THAT TREKKED
SOUTH OVERNIGHT HAS ENDED THE HIGH WINDS, FOR THE TIME BEING, AND
THE EXTREME FIRE WEATHER THREAT. THIS FRONT IS RESPONSIBLE FOR THE
DIP IN TEMPERATURES THAT YOU'LL FEEL ON YOUR SKIN TODAY IF YOU GO
OUTSIDE AND THAT DUSTING OF SNOW, SOME PLACES AROUND AN INCH, THAT
YOU MAY HAVE WOKEN UP TO. MOST OF THE PRECIPITATION HAS LEFT THE
CWA, JUST TO OUR SOUTH ALONG I-25 THERE HAS BEEN A PESKY SNOW BAND
WITH AN ORIENTATION WEST TO EAST; HOWEVER, THIS BAND SHOULD STAY TO
OUR SOUTH AS THE FRONT CONTINUES ITS SOUTHERN PUSH. A CAVEAT,
MODERATE SNOW WILL CONTINUE TO FALL ACROSS THE SIERRA-MADRE AND
SNOWY RANGES WHERE AN ADDITIONAL 3 TO 5 INCHES IS LIKELY THROUGH
THIS AFTERNOON. THEREFORE, WINTER WEATHER ADVISORIES REMAIN OUT
UNTIL 8PM THIS EVENING. THEREAFTER, BENIGN CONDITIONS WILL DOMINATE
THE REMAINDER OF THE EVENING INTO TONIGHT ACROSS THE CWA AS A RIDGE
ALOFT PUSHES IN.
SO, NOW LETS LOOK AT SUNDAY AND WHAT WE CAN EXPECT. AT THE START OF
THE DAY INTO THE EARLY AFTERNOON HOURS WILL BE PLEASANT, LIGHT WINDS
AND MAINLY CLEAR SKIES. THEN THINGS BEGIN TO CHANGE FOR THE LATTER
PART OF THE AFTERNOON, THE SURFACE GRADIENT TIGHTENS ACROSS THE
HIGHER TERRAIN WHILE A LEE-SIDE TROUGH DEVELOPS TO THE EAST,
ESSENTIALLY OVER THE I-25 CORRIDOR. THIS COMBINED WITH A 70 KNOT
700MB JET AND SUBSIDENCE, SURFACE WINDS WILL REALLY RAMP UP ONCE
AGAIN, ESPECIALLY IN THE WIND PRONE AREAS ALONG I-25 AND I-80, WITH
GUSTS EXCEEDING 60MPH. THESE STRONGER WINDS WILL PERSIST BEYOND THE
SHORT TERM PERIOD INTO THE LONG TERM AND MAY INITIATE THE NEED FOR
MORE WIND PRODUCTS THAT WILL BE ISSUED LATER THIS AFTERNOON. IF YOU
WERE ONE OF THE LUCKY ONES AND RECEIVED THAT DUSTING OR SO OF SNOW,
YOU MAY BE WONDERING IF MORE IS ON THE WAY? WELL, I HAVE SOME BAD
NEWS ESPECIALLY FOR THE SNOW LOVERS OUT THERE, WITH MINIMAL
PRECIPITATION CHANCES, NO MORE SNOW IS IN THE FORECAST FOR THE SHORT
TERM PERIOD. THE OTHER THING YOU MAY HAVE NOTICED THIS MORNING, OR
FELT, IS THAT THE AIR FELT A LITTLE BIT CRISPER. EXPECT COOLER
TEMPERATURES TODAY WITH HIGHS ONLY TOPPING OUT IN THE 40S TO NEAR 50
WHILE LOWS TONIGHT WILL DIP INTO THE UPPER 10S TO 20S. THESE COOLER
TEMPS ARE SHORT LIVED, THEY REBOUND NICELY FOR SUNDAY WITH HIGHS
SOARING BACK INTO THE UPPER 40S TO MID/UPPER 50S, POSSIBLY NEAR 60
FOR A FEW OF THE WARMER LOCATIONS MAINLY EAST OF I-25. WHILE LOWS ON
SUNDAY WILL ONLY DROP INTO THE MID/UPPER 30S TO LOWER 40S.
LONG TERM /MONDAY THROUGH FRIDAY/
ISSUED AT 131 PM MST SAT DEC 20 2025
THE LONG TERM FORECAST IS MAINLY DOMINATED BY AN
UPPER RIDGE PATTERN CENTERED OVER EASTERN TEXAS FOR THE MOST PART.
HOWEVER, MONDAY WILL START WITH HIGH WINDS THAT WILL HAVE CONTINUED
FROM SUNDAY NIGHT. THE PRESSURE GRADIENT SLOWLY RELAXES THROUGHOUT
THE DAY CAUSING THE 700MB JET TO WEAKEN. EARLY MORNING MONDAY THE
700MB JET WILL CONTAIN WINDS BETWEEN 60 TO 70KTS WITH STRONG
SUBSIDENT FLOW OVER SOUTHEAST WYOMING. AS THE JET WEAKENS, THE WINDS
SLOWLY DECREASE TO 45 TO 55KTS BY THE EARLY EVENING. SO WHILE WINDS
WILL CONTINUE TO BE GUSTY THEY SHOULD BE OUT OF THE HIGH WIND
CRITERIA BY LATE AFTERNOON TO EARLY EVENING. AS THESE WINDS DIE DOWN
THE UPPER LEVEL RIDGE BECOMES MORE AMPLIFIED AS AN UPPER LEVEL LOW
MOVES CLOSER TO THE PACIFIC NORTHWEST. THE WINDS WILL BE QUITE WEAK
COMPARED TO THE PREVIOUS WEEK BUT STILL MAINTAIN A SLIGHT BREEZE
TUESDAY INTO WEDNESDAY. 700MB TEMPERATURES ARE EXPECTED TO RAISE
FROM THE 3 TO 4C RANGE ON MONDAY INTO THE 5 TO 6C RANGE ON TUESDAY
INTO WEDNESDAY. THIS SLIGHT INCREASE IN 700MB TEMPERATURES WILL LEAD
TO SURFACE TEMPERATURES TO BU IN THE 50'S WEST OF I-25 AND INTO THE
60'S EAST OF I-25 TO CONTINUE THIS WARM PATTERN. THERE IS A SLIGHT
DISTURBANCE IN THE UPPER LEVELS COME WEDNESDAY AFTERNOON INTO
THURSDAY (CHRISTMAS). WEDNESDAY AFTERNOON, THE UPPER LEVEL LOW DIVES
DOWN THE PACIFIC COASTLINE SENDING A SHORTWAVE ACROSS OUR RIDGE
ALONG THE CANADIAN BORDER. THE SHORTWAVE WILL PRODUCE A COLD FRONT
ACROSS SOUTHEAST WYOMING AND THE PANHANDLE PRODUCING SOME POSSIBLE
SNOW SHOWERS FOR THE MOUNTAINS AND AREAS WEST OF I-25. GIVEN THE
CONTINUED WESTERLY FLOW ITS A LITTLE UNCERTAIN IF THOSE SHOWERS WILL
CONTINUE INTO THE LOWER ELEVATIONS. ALSO, DUE TO THE SHORTWAVE
COMPRESSING THE PRESSURE GRADIENT AS IT TRAVELS EASTWARD, IT COULD
ALSO RENEW THE POSSIBILITY OF ANOTHER HIGH WIND EVENT. LOOKING AT
CLUSTER ANALYSIS THERE IS SOME VARIABILITY INTO THE HOW FAR THE
SHORTWAVE IS ACTUALLY ABLE TO DIG OVER THE ROCKY MOUNTAINS. SO THIS
SHORTWAVE WILL BE THE NEXT FEATURE TO KEEP AN EYE ON IN THE LONG
TERM PERIOD FOR POSSIBLE IMPACTS.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1030 AM MST SAT DEC 20 2025
LOW CIGS FOR KCYS SHOULD CLEAR OUT AND LIFT OVER THE NEXT HOUR
OR SO AS COLD FRONT CONTINUES TO PUSH SOUTH. OTHERWISE, THERE
SHOULD BE NO OTHER AVIATION CONCERNS AS VFR CONDITIONS SHOULD
PREVAIL FOR THE DURATION OF THIS TAF PERIOD. BREEZY CONDITIONS
WILL PERSIST ACROSS WYOMING TERMINALS THROUGH ABOUT 00Z SUNDAY,
CONTINUING A DOWNWARD TREND TO GENERALLY LESS THAN 15 KNOTS THIS
EVENING AND OVERNIGHT. THESE CALMER CONDITIONS WILL HOLD FIRM
FOR MOST OF THIS TAF PERIOD, BUT JUST OUT SIDE THIS FORECAST,
WINDS RAMP UP ONCE AGAIN.
CYS WATCHES/WARNINGS/ADVISORIES
WY...WINTER WEATHER ADVISORY UNTIL 8 PM MST THIS EVENING FOR WYZ112-
114.
NE...NONE.
SHORT TERM...RZ
LONG TERM...MM
AVIATION...RZ
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page