791
FXUS65 KCYS 171130
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
430 AM MST WED DEC 17 2025
KEY MESSAGES
- WIDESPREAD STRONG TO LOCALLY DAMAGING WINDS WILL RETURN TODAY
THROUGH THURSDAY MORNING. ANOTHER SIGNIFICANT WIND EVENT IS
EXPECTED THURSDAY NIGHT INTO FRIDAY, POSSIBLY LINGERING INTO
EARLY SATURDAY.
- WIDESPREAD GUSTS OF 60 TO 80 MPH ARE EXPECTED TODAY IN
SOUTHEAST WYOMING. THIS WILL TRANSITION TO GUSTS OF 55 TO 65
MPH OVER THE HIGH PLAINS WEDNESDAY NIGHT INTO THURSDAY MORNING
BEHIND A COLD FRONT.
- I-25 WIND PRONE AREAS CAN EXPECT WIND GUSTS UP TO 90 MPH
WEDNESDAY, PARTICULARLY IN PLATTE COUNTY.
- HIGH GRASSLAND WILDFIRE DANGER WILL BE PRESENT THROUGH FRIDAY.
- A COLD FRONT WILL SWEEP THROUGH THIS AFTERNOON AND EVENING,
BRINGING SCATTERED RAIN AND SNOW SHOWERS. TRAVEL IMPACTS ARE
POSSIBLE ALONG AND WEST OF THE LARAMIE RANGE.
SHORT TERM /THROUGH THURSDAY/
ISSUED AT 330 AM MST WED DEC 17 2025
FORECAST REMAINS ON TRACK FOR OUR EXPECTED LONG DURATION HIGH
WIND EVENT ACROSS THE REGION BEGINNING TODAY AND CONTINUING
THROUGH FRIDAY. MODELS CONTINUE TO SHOW AN IMPRESSIVE UPPER
LEVEL PACIFIC SYSTEM MOVING INLAND TODAY AND QUICKLY
OVERSPREADING INTO THE REGION, WITH AN UPPER LOW DEVELOPING JUST
ALONG THE BORDERS OF THE US AND CANADA IN MONTANA AND THEN
TRACKING ACROSS THE NORTHERN PLAINS AND INTO THE GREAT LAKES
THURSDAY INTO FRIDAY. MOVING DOWN TO 700MB, THE JET STREAK WILL
BEGIN TO STRENGTHEN IN A FEW HOURS FIRST ABOVE OUR WIND PRONE
LOCATIONS, AND THEN OVERSPREAD ACROSS MOST OF EASTERN WYOMING
THROUGH THE AFTERNOON AND EVENING HOURS, WITH A SECOND JET
STREAK DEVELOPING OVERNIGHT WEDNESDAY INTO THURSDAY AS THE LOW
STRENGTHENS AND THEN SWINGS THIS FEATURE INTO THE WY/SD/NE
BORDER REGION THROUGH THURSDAY AFTERNOON. SPEEDS AT THE 700MB
LEVEL OF 80-90+ KNOTS ARE EXPECTED OVER OUR CWA, WITH THE
INITIAL STRONGEST ROUND THIS AFTERNOON WITH A SECOND OCCURRING
THURSDAY MORNING. FINALLY, SURFACE GRADIENTS WILL SEE AN
IMPRESSIVE INCREASE WITH THIS SYSTEM, AS CRAIG TO CASPER
PRESSURE GRADIENTS PEAK AT AROUND 90 METERS BY THIS AFTERNOON.
ALL OF THIS IS EXPECTED TO FUEL OUR NEXT ROUND OF HIGH WIND
ACTIVITY, WITH WIDESPREAD GUSTS OF 60-80 MPH FOR MOST OF
SOUTHEAST WYOMING AND THE NEBRASKA PANHANDLE, WITH GUSTS OF
85-90+ MPH POSSIBLE PRIMARILY INTO PLATTE COUNTY AS THIS
ACTIVITY BECOMES ENHANCED BY MOUNTAIN WAVES. THE TWO CAVEATS OF
NOTE HOWEVER WILL BE HOW BRIEF THE WINDOW FOR VERY STRONG WINDS
WILL BE THIS AFTERNOON LEADING TO ONLY A QUICK CHANCE OF THESE
85-90 MPH POTENTIAL GUSTS, AS WELL AS THE EXPECTATION OF THE
SECOND STREAK INTO THURSDAY MORNING OVER THE NEBRASKA PANHANDLE
WHICH WILL BE A POOR TIME FOR THE PRODUCTION OF STRONGER WIND
GUSTS. NONETHELESS, OMEGA VALUES SHOW AT LEAST SOME DOWNWARD
FORCING OF THESE WINDS EVEN IF IT ISN'T THE MOST FAVORABLE
SETUP, AND WITH THE POTENTIAL FOR AT LEAST A FEW GUSTS ACHIEVING
HIGH WIND CRITERIA, HAVE MADE THE DECISION TO UPGRADE TO
WARNINGS IN THE NEBRASKA PANHANDLE THIS MORNING. ALONGSIDE THIS,
HAVE EXTENDED THE HIGH WIND WARNINGS FOR OUR USUAL WIND PRONE
LOCATIONS (ARLINGTON, BORDEAUX, LARAMIE SUMMIT) THROUGH 15-18Z
THURSDAY TO ACCOUNT FOR SOME DOWNWARD MIXING OF THIS SECOND JET
STREAK AS WELL. AND FINALLY, WHILE WE SHOULDN'T ACHIEVE
CRITERIA FOR RED FLAG CONDITIONS ACROSS THE CWA, THE HIGH WINDS
ALONGSIDE FAIRLY LOW RH VALUES (20-25%) ACCOMPANIED BY THE LACK
OF NOTABLE PRECIPITATION SHOULD FUEL ENHANCED FIRE WEATHER
DANGER, AND IF ANY FIRES DO CROP UP EXPECT A RAPID SPREAD,
PRIMARILY IN OUR HIGH PLAINS ZONES.
WITH THIS SYSTEM, A COLD FRONT WILL MAKE ITS WAY ACROSS LATER
THIS EVENING, BRINGING A QUICK CHILL AS WE DESCEND BACK BELOW
FREEZING TONIGHT AND ALONGSIDE IT WILL BE THE POTENTIAL FOR A
QUICK SHOT OF PRECIPITATION, STRONGEST ACROSS OUR WESTERN
COUNTIES. STILL SEEING THE SIGNAL OF SOME FAVORABLE LAPSE RATES
AND THE POTENTIAL FOR QUICK SNOW SHOWERS THAT COULD EVEN TURN
INTO A STRONGER BAND THAT COULD PRODUCE SNOW SQUALL CRITERIA
INCLUDING BRIEF HEAVY SNOWFALL BRINGING VISIBILITIES UNDER A
QUARTER OF A MILE, AS WELL AS FLASH FREEZING LOCATIONS THAT GET
THE QUICK AND HEAVY SNOW. OTHERWISE THE MOUNTAINS HERE (SNOWY
AND SIERRA-MADRE RANGES) CONTINUE TO SEE THE POTENTIAL OF
AROUND 5-10 INCHES FROM THIS EVENT, WITH WINTER WEATHER
ADVISORIES STARTING LATER THIS MORNING FOR THOSE LOCATIONS.
BUT WE AREN'T DONE YET, AND ON THE HEELS OF THIS FIRST ROUND OF
HIGH WINDS, A SECOND WIND EVENT IS ONCE AGAIN EXPECTED LATER
THURSDAY INTO FRIDAY, POSSIBLY EVEN LINGERING THROUGH EARLY
SATURDAY, AS ANOTHER PACIFIC SYSTEM MOVES INLAND AND TIGHTENS
OUR PRESSURE GRADIENTS ONCE AGAIN WHILE ENHANCING THE 700MB FLOW
OVER THE REGION. CURRENTLY WE ARE SHOWING THIS YET AGAIN
OVERSPREADING MUCH OF SOUTHEASTERN WYOMING, WITH FURTHER WIND
HIGHLIGHTS YET AGAIN EXPECTED FOR MUCH OF THE REGION. THAT
BEING SAID, WITH ONGOING HIGH WIND WARNINGS ACROSS THE CWA AND
THE LAPSE OF AROUND 6-12 HOURS EXPECTED BETWEEN THESE EVENTS,
HAVE ELECTED TO HOLD OFF ON ANY HIGHLIGHTS FOR NOW, BUT WE WILL
LIKELY SEE ONE WIND EVENT LEAD INTO ANOTHER THROUGH THE COURSE
OF THE WEEK. OTHERWISE BEHIND THE AFOREMENTIONED FRONT ABOVE,
TEMPERATURES SHOULD BECOME A LOT MORE REASONABLE FOR DECEMBER ON
THURSDAY AS HIGHS PEAK IN THE 30'S TO 40'S, BUT WE'LL CATAPULT
RIGHT BACK INTO THE ABNORMAL WARMTH JUST BEYOND THE SHORT TERM
ON FRIDAY, SO THIS WILL BE A BRIEF RETURN TO WINTER AT BEST.
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/
ISSUED AT 400 PM MST TUE DEC 16 2025
A BROAD RIDGE STARTS TO DEVELOP OVER THE WESTERN
UNITED STATES GIVING US A WARM UP AFTER THE COLD FRONT PASSES
THROUGH ON THURSDAY. THE WINDS WILL GRADUALLY WEAKEN FRIDAY INTO
SATURDAY AS THE WEAK CLIPPER SYSTEM PUSHES EAST AND THE RIDGE AXIS
MOVES OVER THE INTERMOUNTAIN WEST. ANOTHER QUICK SHORTWAVE PASSES
THROUGH THE REGION SATURDAY MORNING AND INTO THE AFTERNOON. HOWEVER,
WITH THE CONTINUED WESTERLY FLOW THE STOUT DRY LAYER NEAR THE
SURFACE WILL LIKELY KEEP ANY PRECIPITATION CHANCES CONFINED TO THE
MOUNTAINOUS REGIONS. 700MB TEMPERATURES LOOK TO BE IN THE POSITIVES
MEANING THAT ANY PRECIPITATION THAT FALLS MAY COME DOWN AS RAIN OR A
RAIN/SNOW MIX, WHILE ONLY THE MOUNTAIN PEAKS WILL LIKELY SEE SNOW.
THESE WARMER 700MB TEMPERATURES LOOK TO REMAIN THROUGH THE WEEKEND
AND INTO THE BEGINNING OF THE WORK WEEK. THIS WARM AIRMASS COUPLED
WITH OUR WESTERLY FLOW WILL KEEP TEMPERATURES IN THE 50'S AND 60'S
FOR THE LOWER ELEVATIONS AND 40'S AND 50'S IN THE HIGHER ELEVATIONS
WEST OF I-25. THE WINDS LOOK TO TAKE A QUICK BREAK SATURDAY, BUT
WILL MAKE A RETURN SUNDAY INTO MONDAY AS A SHORTWAVE REVIVES OUR
700MB JET FOR POSSIBLE GUSTY WINDS BEFORE DIEING OFF AGAIN ON
TUESDAY.
AVIATION /12Z TAFS THROUGH 12Z THURSDAY/
ISSUED AT 429 AM MST WED DEC 17 2025
VFR CONDITIONS MOSTLY EXPECTED OVER THE NEXT 24 HOURS. WINDS
THE PRIMARY HAZARD AS ALL SITES SEE GUSTS INCREASE THROUGH THE
AFTERNOON AT 30-60+ KNOTS, ALONGSIDE LOW LEVEL WIND SHEAR AT
AROUND 2000 FEET IN EXCESS OF 50-70 KNOTS. CIGS START OUT HIGH,
AND SHOULD DROP TO MID LEVELS AS A ROUND OF PRECIPITATION MOVES
INTO THE REGION, WITH THE HIGHEST PRECIPITATION CHANCES FOR
KRWL/KLAR LATER THIS AFTERNOON AND EVENING. KRWL MAY SEE MVFR
OR LOWER CONDITIONS AS PRECIPITATION MOVES THROUGH INCLUDING
CIGS DROPPING TO 3000 FEET OR LOWER.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HIGH WIND WARNING FROM 11 AM THIS MORNING TO 11 AM MST
THURSDAY FOR WYZ102-108.
HIGH WIND WARNING UNTIL MIDNIGHT MST TONIGHT FOR WYZ101.
HIGH WIND WARNING UNTIL MIDNIGHT MST TONIGHT FOR WYZ103>105-
109.
HIGH WIND WARNING FROM 8 AM THIS MORNING TO 11 AM MST THURSDAY
FOR WYZ106.
HIGH WIND WARNING FROM 8 AM THIS MORNING TO MIDNIGHT MST
TONIGHT FOR WYZ107-113-115.
HIGH WIND WARNING UNTIL 11 AM MST THURSDAY FOR WYZ110.
WINTER WEATHER ADVISORY FROM 9 AM THIS MORNING TO 6 PM MST
THIS EVENING FOR WYZ112-114.
HIGH WIND WARNING UNTIL 11 AM MST THURSDAY FOR WYZ116.
HIGH WIND WARNING FROM 8 AM THIS MORNING TO 8 AM MST THURSDAY
FOR WYZ117.
HIGH WIND WARNING FROM 11 AM THIS MORNING TO MIDNIGHT MST
TONIGHT FOR WYZ118-119.
NE...HIGH WIND WARNING FROM 11 AM THIS MORNING TO 11 AM MST
THURSDAY FOR NEZ002-095.
HIGH WIND WARNING FROM 2 PM THIS AFTERNOON TO 11 AM MST
THURSDAY FOR NEZ003-019>021-054-055-096.
SHORT TERM...CG
LONG TERM...MM
AVIATION...CG
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