035
FXUS65 KCYS 190049
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
500 PM MST MON NOV 18 2024
KEY MESSAGES
- HIGH WIND WARNINGS REMAIN IN EFFECT UNTIL 2 AM TUESDAY FOR THE
SOUTHEAST WYOMING WIND PRONE LOCATIONS AS WELL AS FOR
WHEATLAND AND CHEYENNE.
- COLD AND BLUSTERY WEATHER LINGERING ON TUESDAY.
- WINDY AND NOT AS COLD FOR WEDNESDAY WITH ANOTHER ROUND OF
STRONG WINDS POSSIBLE FOR THE SOUTHEAST WYOMING WIND PRONE
LOCATIONS, ESPECIALLY THE SNOWY RANGE FOOTHILLS ALONG I-80.
SHORT TERM /THROUGH TUESDAY NIGHT/
ISSUED AT 208 PM MST MON NOV 18 2024
TONIGHT...PRIMARY CHALLENGE WILL AGAIN BE THE WINDS. A RATHER STRONG
COLD FRONT SWEEPS FROM WEST TO EAST ACROSS OUR COUNTIES THIS EVENING
WITH IMPRESSIVE COLD AIR ADVECTION AND PRESSURE RISES BEHIND THE
COLD FRONT. WITH THE STRENGTH OF THE COLD AIR ADVECTION, OUR LOCAL
WIND MODELS, AND WITH 700 MB WINDS PROGGED TO BE 50 TO 60 KNOTS THIS
EVENING, WE HAVE DECIDED TO UPGRADE THE WATCH TO A HIGH WIND WARNING
FOR WHEATLAND AND CHEYENNE THROUGH 2 AM. THE WARNING STILL LOOKS ON
TRACK FOR ARLINGTON, BORDEAUX AND THE I-80 SUMMIT. SCATTERED SNOW
SHOWERS WILL OCCUR OVER AND NEAR THE SNOWY, NORTHERN LARAMIE AND
SIERRA MADRE RANGES MAINLY WITH THE FRONT, AS WELL AS NEARBY
LOCATIONS OF CONVERSE COUNTY.
TUESDAY...EXPECT A BLUSTERY AND QUITE CHILLY DAY WITH BRISK
NORTHWEST FLOW ALOFT AND 700 MB TEMPERATURES NEAR -13 CELSIUS
YIELDING MAXIMUM TEMPERATURES ONLY FROM 25 TO 30 DEGREES WEST OF I-
25, WITH MID 30S TO MID 40S EAST OF I-25. WINDS LOOK TO REMAIN BELOW
HIGH WIND CRITERIA BASED ON LOCAL WIND MODELS AND PROGGED WINDS
ALOFT. SCATTERED OROGRAPHIC SNOW SHOWERS WILL OCCUR FOR THE SNOWY
AND SIERRA MADRE RANGES WITH THE WINDS PRODUCING AREAS OF BLOWING
SNOW.
TUESDAY NIGHT...LOW AND MID LEVEL GRADIENTS STRENGTHEN ONCE AGAIN
AND LOCAL WIND MODELS SUGGEST ANOTHER HIGH WIND EVENT POSSIBLE FOR
OUR SOUTHEAST WYOMING WIND PRONE LOCATIONS. WITH THE CURRENT HIGH
WIND WARNING IN EFFECT, FEEL IT WOULD BE BEST TO HOLD OFF ON MORE
HIGHLIGHTS FOR NOW TO AVOID CONFUSION. ANOTHER COLD OVERNIGHT WITH
700 MB TEMPERATURES NEAR -12 CELSIUS. WITH DRY LOW AND MID LEVELS OF
THE ATMOSPHERE, NO PRECIPITATION IS ANTICIPATED.
WEDNESDAY...NORTHWEST FLOW ALOFT CONTINUES WITH HEIGHTS ALOFT RISING
SIGNIFICANTLY. WITH 700 MB TEMPERATURES NEAR -4 CELSIUS, MAXIMUM
TEMPERATURES WILL BE WARMER, IN THE 40S. LOCAL WIND MODELS, AS WELL
AS LOW AND MID LEVEL GRADIENTS, AND 700 MB WINDS NEAR 50 KNOTS
SUGGEST MORE HIGH WINDS POSSIBLE THROUGH THE DAY, PRIMARILY FOR OUR
WIND PRONE LOCATIONS SUCH AS ARLINGTON, BORDEAUX AND THE INTERSTATE
80 SUMMIT. CONTINUED DRY WITH LIMITED LOW AND MID LEVEL
MOISTURE.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
ISSUED AT 208 PM MST MON NOV 18 2024
WIND CORRIDORS OF SOUTHEAST WYOMING ON WEDNESDAY NIGHT AS STRONG
PRESSURE GRADIENTS REMAIN PRESENT OVER THE HIGHER TERRAIN. IN-HOUSE
MACHINE LEARNING GUIDANCE SUPPORTS THIS EVENT CONTINUING THROUGH AT
LEAST THE FIRST PORTION OF WEDNESDAY NIGHT IN THE SNOWY RANGE
FOOTHILLS WHERE PROBABILITIES OF EXCEEDING 50 KNOTS ARE OVER 60
PERCENT. THIS HIGH WIND EVENT WILL ONLY GRADUALLY RELAX THROUGH THE
NIGHT AND THROUGH THE DAY ON THURSDAY AS SOME MILD GRADIENT FORCE
AND STRONGER FLOW IN THE MID-LEVELS REMAIN PRESENT. RIDGING WILL
EVENTUALLY DEVELOP OVER THE CENTRAL ROCKIES AND HIGH PLAINS LATER ON
THURSDAY INTO FRIDAY. AS A RESULT, EXPECT WARMING TEMPERATURES ON
BOTH THURSDAY AND FRIDAY AT THE SURFACE WITH HIGHS EVENTUALLY
RETURNING TO ABOVE-AVERAGE. EXPECT DRY WEATHER THROUGH AT LEAST
SATURDAY EVENING AS RIDGING CONTINUES.
BY SATURDAY NIGHT INTO SUNDAY, FORECAST GUIDANCE BEGINS TO DIVERGE
WITH VARIOUS GLOBAL MODELS SHOWING DIFFERENT VERSIONS OF A SHORTWAVE
TROUGH MOVING THROUGH THE WESTERN CONUS. ENSEMBLE GUIDANCE IS HIGHLY
DISPERSIVE WITH THIS SYSTEM, SHOWING A WIDE RANGE OF SOLUTIONS THAT
CONTINUE TO VARY QUITE A BIT FROM RUN TO RUN. THE MOST LIKELY
OUTCOME AS OF MONDAY AFTERNOON FAVORS A COOL-DOWN ON SUNDAY WITH AN
UPTICK IN WINDS, PERHAPS UP TO HIGH-WIND CRITERIA, AS WELL AS SOME
LIGHT TO MODERATE SNOW FOR THE MOUNTAINS. SOME ENSEMBLE MEMBERS
FAVOR A STRONGER SYSTEM WITH MORE PRECIPITATION BY MONDAY, HOWEVER
THESE SNOWIER SOLUTIONS ARE SEEN IN ONLY ABOUT 20% OF GUIDANCE.
THEREFORE, WE WILL FAVOR COOLER TEMPS BUT MAINLY DRY WEATHER FOR
MOST LOCATIONS OUTSIDE OF THE HIGHER TERRAIN FOR NOW.
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 500 PM MST MON NOV 18 2024
A STRONG COLD FRONT WILL PUSH ACROSS THE REGION THIS EVENING. NOT
MUCH PRECIPITATION IS EXPECTED AT AREA TERMINALS, BUT VERY WINDY
CONDITIONS EXPECTED ACROSS SOUTHEAST WYOMING AND MOST OF WESTERN
NEBRASKA THROUGH TONIGHT AND INTO WEDNESDAY WITH A BRIEF LULL IN
WINDS BEFORE SUNRISE WEDNESDAY.
HAZARDS/WEATHER TRENDS: VFR WILL PREVAIL AT ALL TERMINALS TONIGHT
THROUGH 18Z TUESDAY. CAN'T RULE OUT A FEW SNOW SHOWERS NEAR KRWL AND
KLAR THIS EVENING, BUT ACTIVITY SHOULD BE LIGHT ENOUGH TO KEEP VFR
PREVAILING. ANY SNOW SHOWERS OR FLURRIES SHOULD END BY 03Z THIS
EVENING. WINDY CONDITIONS EXPECTED ALL NIGHT WITH WESTERLY
WINDS GUSTING 40 TO 50 KNOTS AT THE SE WYOMING TERMINALS, AND 30 TO 40
KNOTS ACROSS WESTERN NEBRASKA.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HIGH WIND WARNING UNTIL 2 AM MST TUESDAY FOR WYZ106-107-110-
116>118.
NE...NONE.
SHORT TERM...RUBIN
LONG TERM...MAC
AVIATION...TJT
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