040
FXUS65 KCYS 172309
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
409 PM MST SUN NOV 17 2024
KEY MESSAGES
- A HIGH WIND WATCHES REMAIN IN EFFECT FOR THE SOUTHEAST WYOMING
WIND PRONE AREAS FROM 8AM MST MONDAY TO AFTER MIDNIGHT ON
TUESDAY.
- THE NEXT STORM SYSTEM WINDS WILL BRING ANOTHER ROUND OF STRONG WINDS
AND SCATTERED SNOW SHOWERS MONDAY AND MONDAY NIGHT, FOLLOWED
BY MUCH COLDER TEMPERATURES TUESDAY.
- A PROLONGED PERIOD OF STRONG WINDS IS EXPECTED TUESDAY THROUGH
THURSDAY. HIGH WINDS WILL BE POSSIBLE IN THE SOUTHEAST WYOMING
WIND PRONES DURING THIS TIME.
SHORT TERM /THROUGH TUESDAY/
ISSUED AT 1253 PM MST SUN NOV 17 2024
LATEST UPPER AIR ANALYSIS DEPICTS A SOMEWHAT SPLIT FLOW REGIME WITH
A CLOSED LOW DEVELOPING ACROSS THE FOUR CORNERS, LEAVING BEHIND A
SHORTWAVE TROUGH PUSHING EAST ACROSS THE NORTHERN PORTION OF THE
INTERMOUNTAIN WEST INTO THE HIGH PLAINS. LOOKING OFF TO THE EAST,
STARTING TO SEE THE LARGE SCALE BLOCKING RIDGE DEVELOP ACROSS THE
GULF AND EXTENDING NORTHWARD INTO THE GREAT LAKES. MUCH OF THIS
BLOCKING FEATURE WILL HELP SHAPE THE TRAJECTORY OF THE INCOMING
SYSTEMS, WHICH WILL DRIVE THE WEATHER ACROSS THE CWA. CONDITIONS
THROUGHOUT THE MORNING HAVE SEEN GUSTY TO STRONG WINDS ACROSS
PORTIONS OF SOUTHEAST WYOMING, WITH INHERITED HIGH WIND WARNINGS
ACROSS OUR WIND PRONE AREAS IN ARLINGTON AND BORDEAUX, IN ADDITION
TO NORTHWEST CARBON COUNTY, THROUGH 3PM TODAY. RIDING WITHIN THE
MAIN FLOW, DISTURBANCES HAVE BEGUN KICKING UP WIND SPEEDS ACROSS
NORTHERN HALF OF PLATTE COUNTY IN COLEMAN ON THE I-25 CORRIDOR. WENT
AHEAD AND ADDED THE REST OF PLATTE COUNTY TO THE HIGH WIND WARNING
THROUGH 3PM. SHOULD BEGIN TO SEE STRONG WINDS DECREASE IN THE LATE
AFTERNOON HOURS AS THE MAIN SHORTWAVE EJECTS OUT TO THE EAST
TOWARDS THE MIDWEST WITH QUASI-ZONAL FLOW BRIEFING DEVELOPING
ACROSS THE NORTH CONUS.
GOOD AMOUNT OF MODEL CONSISTENCY THROUGHOUT THE COURSE OF LAST WEEK,
WITH THE DEVELOPMENT AND PLACEMENT OF THE AFOREMENTIONED CUTOFF LOW,
WHICH IS EXPECTED TO LIFT TO THE NORTHEAST FROM THE ARIZONA/NEW
MEXICO TOWARDS THE HIGH PLAINS. MUCH OF THE PATH OF THIS LOW WILL BE
INFLUENCED BY THE BLOCKING FEATURE ACROSS THE GULF, WITH MODELS
COMING INTO MUCH BETTER FOCUS AS THE UPPER LEVEL RIDGE WILL SLIGHTLY
BREAK DOWN, ALLOWING FOR THE CLOSED LOW TO TRACK A BIT FURTHER
EAST AND ULTIMATELY REDUCING UPSLOPE FLOW ACROSS THE CWA BEFORE
BECOMING ABSORBED INTO THE INTO THE NEXT PACIFIC TROUGH BEGINS
TO SWING THROUGH THE AREA MONDAY AFTERNOON AND EVENING.
CONFIDENCE HAS CONTINUED TO INCREASE FOR ADDITIONAL HIGH WINDS
AS THE PRESSURE GRADIENTS TIGHTEN BETWEEN THESE TWO FEATURES,
WITH THE NBM V4.2 PROBABILITY OF EXCEEDING 48KTS HAS BEGUN TO
COME INTO AGREEMENT WITH THE LATEST MODEL GUIDANCE, WITH A HIGH
LIKELIHOOD OF GREATER THAN 48 KNOT WINDS ACROSS THE SOUTHERN TO
CENTRAL LARAMIE RANGE AND SPILLING OVER INTO THE I-25 CORRIDOR
NEAR BORDEAUX, AND EVEN ACROSS THE I-80 CORRIDOR ALONG THE
SUMMIT AND ARLINGTON. THESE SIGNALS GENERALLY HAVE A HIGH
LIKELIHOOD FOR CRITICAL LEVEL WIND GUST THRESHOLDS WITH THE NBM
UNDER FORECASTING WIND SPEEDS FOR WYOMING. WILL ALSO NEED TO
MONITOR FOR HIGH WINDS THROUGH LARAMIE COUNTY, INCLUDING THE
CITY OF CHEYENNE, WITH THE NBM V4.2 PROBABILITY OF EXCEEDING
41KTS HOVERING ON THE NORTH SIDE OF 60% FOR STRONGER WINDS.
ALTHOUGH, LOCAL IN-HOUSE MODEL GUIDANCE DOES KEEP KCYS WINDS
ELEVATED, BUT NOT QUITE REACHING CRITICAL THRESHOLDS MONDAY INTO
TUESDAY, UNLIKE THE WIND PRONE COUNTERPARTS. WENT AHEAD AND
ISSUED HIGH WIND WATCHES ACROSS OUR WIND PRONE AREAS IN KBRX AND
KARL, IN ADDITION TO THE SUMMIT AND WEST LARAMIE COUNTY.
IN ADDITION TO THE WINDS, WILL SEE SOME SNOW DEVELOP ACROSS OUR
WESTERN ZONES AND ACROSS THE HIGHER TERRAINS TOMORROW MORNING WITH
THE ARRIVAL OF THE FRONTAL BOUNDARY. AS PREVIOUSLY MENTIONED, NOT
EXPECTING MUCH PRECIPITATION THE MAIN LIFT BEING ASSOCIATED WITH THE
FRONT AND NOT MUCH INFLUENCE WITH THE UPPER LEVEL CLOSED LOW WHICH
WOULD HAVE PROVIDED BETTER UPSLOPE FLOW AND INCREASED PRECIPITATION
FOR THE REGION. NEVERTHELESS, STILL SOME MINOR SNOW
ACCUMULATIONS ARE POSSIBLE, PRIMARILY ACROSS THE HIGHER
TERRAINS, WITH THE SIERRA MADRES HOVERING AROUND 2 TO 4 INCHES
AND SNOWY RANGE 1 TO 2 INCHES DUE TO A SHADOWING ACROSS THE
SNOWY RANGE FROM THE OVERALL FLOW PATTERN. SOME CONCERNS WITH
THE STRONGER WINDS AND AREAS OF SNOW FOR BLOWING SNOW WILL BE
POSSIBLE, BUT WITH MUCAPE VALUES BEING ESSENTIALLY NON-
EXISTENT, WILL KEEP ANY MENTIONS OF SNOW SQUALLS TO A MINIMUM.
LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/
ISSUED AT 1253 PM MST SUN NOV 17 2024
THE MEDIUM RANGE TO EXTENDED FORECAST REGIME LOOKS TO HAVE VERY
LITTLE IN TERMS OF DETERMINISTIC CHANGES. THE GUSTY WINDS LOOK TO
REMAIN ENTRENCHED ACROSS THE WIND PRONE AND GAP AREAS FOR A
PROLONGED PERIOD AS WELL. WE WILL LIKELY HAVE WIND GUSTS EXCEEDING
50-60MPH IN MANY AREAS OF SOUTHEAST WY FOR EARLY WEDNESDAY MORNING
THROUGH THURSDAY MORNING. OVER THAT PERIOD OF TIME, WE WILL SEE A
SLOW AND GRADUAL DECREASE IN THE GUSTY WINDS TO MORE TYPICAL
(BREEZY) THRESHOLDS OF 10-20MPH. THE GOOD NEWS IS THAT THE CHILLY
TEMPERATURES WE CAN EXPECT TO ACCOMPANY THE GUSTY WINDS ON WEDNESDAY
WILL MAKE A REBOUND BEGINNING THURSDAY. DAYTIME HIGHS IN THE 30S AND
40S ON WEDNESDAY WILL SURGE 10-15 DEGREES FAHRENHEIT FOR AFTERNOON
HIGHS ON THURSDAY. UPPER LEVEL RIDGING WILL AMPLIFY FROM FRIDAY
THROUGH THE SATURDAY, RESULTING IN DRY CONDITIONS AND SLIGHTLY ABOVE
AVERAGE TEMPERATURES PERSISTING. FROM THERE, DIFFERENCES IN
DETERMINISTIC MODELS SHOW A PROGRESSIVE WAVE COMING FROM THE PACIFIC
NW TOWARD OUR CWA. TIMING AND LOCATION ARE AREAS OF CONCERN FOR
WHERE ANY RAIN AND SNOW SHOWERS WOULD EVENTUALLY OCCUR. HIGHEST
CONFIDENCE WOULD BE FOR LIGHT SNOWFALL ACCUMULATIONS IN THE MOUNTAIN
ZONES, WITH COLDER AIR PUSHING IN BEHIND THE UPPER LEVEL
DISTURBANCE BEGINNING ON SUNDAY.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 402 PM MST SUN NOV 17 2024
WINDS EASING THIS EVENING...BUT WILL ONCE AGAIN PICK UP MONDAY.
STRONGER WINDS EXPECTED THAN TODAY AT KRWL...KLAR AND KCYS. VFR
CONDITIONS EXPECTED...BUT STRONG WIND GUSTS MAY PRESENT SOME
FLIGHT IMPACTS AT THESE AIRPORTS.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HIGH WIND WATCH FROM MONDAY MORNING THROUGH LATE MONDAY NIGHT
FOR WYZ106-110-116-117.
NE...NONE.
SHORT TERM...MRD
LONG TERM...BW
AVIATION...GCC
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