776
FXUS65 KCYS 101759
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1159 AM MDT WED SEP 10 2025
KEY MESSAGES
- DAILY CHANCES FOR AFTERNOON SHOWERS AND THUNDERSTORMS CONTINUE
THROUGH THURSDAY WITH GUSTY WINDS, DOWNPOURS, AND ISOLATED
HAIL POSSIBLE.
- A COLD FRONT WILL IMPACT THE AREA LATER THIS WEEK BRINGING
COOLER TEMPERATURES AND CHANCES FOR SHOWERS ON FRIDAY AND
SATURDAY.
SHORT TERM /THROUGH THURSDAY/
ISSUED AT 349 AM MDT WED SEP 10 2025
WITH AN UPPER-LEVEL RIDGE MOVING OVER THE CWA TODAY, EXPECT A MILD
FALL DAY ACROSS THE AREA. SOUTHWEST FLOW ALOFT WILL USHER IN WARMER
700 MB TEMPERATURES AROUND +14C, LEADING TO HIGH TEMPERATURES
ROUGHLY 5 DEGREES ABOVE AVERAGE FOR THIS TIME OF YEAR. HIGHS ACROSS
THE AREA WILL MAINLY BE IN THE 80S WITH PERHAPS EVEN A 90 DEGREE
TEMPERATURES OR TWO FOR PARTS OF THE NEBRASKA PANHANDLE.
UNFORTUNATELY, THE RIDGE WILL NOT BE ENOUGH TO KEEP PRECIPITATION
CHANCES AT BAY. A WEAK SHORTWAVE MOVING THROUGH THE RIDGE THIS
AFTERNOON WILL PROVIDE LIFT FOR SHOWERS AND THUNDERSTORMS TO
DEVELOP. HI-RES GUIDANCE HAS STORMS DEVELOPING BY MID-AFTERNOON
IN SOUTHEAST WYOMING AND PUSHING EASTWARD INTO NEBRASKA BY THE
EVENING HOURS. COVERAGE OF STORMS WILL LIKELY BE LESS THAN
TUESDAY, SO SOME LOCATIONS MAY SEE SOME RAIN WHILE OTHERS MAY
NOT. CANNOT RULE OUT SEVERE STORMS WITH GFS MODEL SOUNDINGS
SHOWING POCKETS OF MUCAPE UP TO 2000 J/KG IN THE PANHANDLE.
STRONGER STORMS COULD CONTAIN SEVERE HAIL AS WELL AS SEVERE
WIND GUSTS WITH DCAPE VALUES OVER 1000 J/KG. STORMS WILL MOVE
OUT DURING THE EVENING HOURS, HOWEVER, A FEW SHOWERS WILL LINGER
INTO THE OVERNIGHT HOURS AS THE DISTURBANCE MOVES OUT OF THE
AREA.
ON THURSDAY, THE UPPER-LEVEL RIDGE WILL BE EAST OF THE CWA, ALLOWING
A DEEP TROUGH TO GRADUALLY MOVE INTO THE AREA. 700 MB TEMPERATURES
WILL BE ROUGHLY THE SAME AS TODAY, RESULTING IN SIMILAR HIGH
TEMPERATURES ON THURSDAY. WITH THE APPROACHING TROUGH, VORTICITY
MAXES WILL MOVE INTO THE CWA, SPARKING MORE STORMS. MODELS SHOW
GREATER COVERAGE OF PRECIPITATION WITH WIDESPREAD SCATTERED SHOWERS
AND STORMS EXPECTED FOR MOST OF THE CWA. WITH MUCAPE VALUES UP TO
1300 J/KG IN THE PANHANDLE ON THURSDAY, CANNOT RULE OUT A MARGINALLY
SEVERE STORM OR TWO. DCAPE VALUES ARE ALSO ABOVE 1000 J/KG SO BOTH
HAIL AND GUSTY WINDS COULD BE POSSIBLE IN STORMS.
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/
ISSUED AT 330 PM MDT TUE SEP 9 2025
LONG TERM SHOULD REMAIN ACTIVE INITIALLY AS A DEEP TROUGH AND
LOW PRESSURE SYSTEM MOVES ACROSS THE REGION, DISPLACING A HIGH
PRESSURE RIDGE OFF TO OUR EAST AND COOLING US BACK OFF, BUT AS
THIS TROUGH WEAKENS OVER THE WEEKEND WE SHOULD SEE PRECIPITATION
CHANCES WANE AND TEMPERATURES MODERATE THEMSELVES TO NEAR NORMAL
TO END THE PERIOD.
THURSDAY SHOULD BE THE LAST DAY OUR REGION REMAINS UNDER THE
INFLUENCE OF THE RIDGE AS IT BEGINS TO RIDE EASTWARDS IN
RESPONSE TO AN APPROACHING PACIFIC TROUGH. THIS TROUGH THEN
MOVES INTO THE REGION THURSDAY INTO FRIDAY, BRINGING AN INCREASE
IN PRECIPITATION CHANCES AND HIGHS DROPPING INTO THE 70'S WITH
EVEN SOME UPPER 60'S SHOWING UP BY SATURDAY. MEANWHILE PWAT
VALUES WILL MAX OUT AROUND 125-150% OF NORMAL, ALLOWING FOR
RAINFALL ACROSS THE ENTIRETY OF THE CWA ON FRIDAY. WHILE
PRECIPITATION CHANCES DO CONTINUE ON SATURDAY, THEY SHOULD BE
WANING AS THE TROUGH WILL BROADEN AND LESS FORCING MAKES ITS WAY
ACROSS OUR AREA. THEN MOVING INTO SUNDAY AND THE BEGINNING OF
NEXT WEEK, A TRANSIENT RIDGE WILL MOVE ACROSS AS THE TROUGH
BREAKS DOWN, BUT ANOTHER WEAKER LOW WILL BE ON THE HEELS OF THIS
SYSTEM JUST BEYOND THE SHORT TERM. THIS OVERALL PATTERN BRINGS
COOLER TEMPERATURES WITH THE COOLEST CONDITIONS EXPECTED ON
SATURDAY, WITH A SLIGHT WARMING TREND FOR SUNDAY AND MONDAY
ALBEIT ONLY A FEW DEGREES AT BEST. MEANWHILE THE PRECIPITATION
CHANCES START OFF STRONG, BUT SHOULD TAPER OFF FOR SUNDAY INTO
MONDAY PRIOR TO THE NEXT SYSTEM MOVING IN. ENSEMBLE MODEL
CLUSTERS ARE IN FAIR AGREEMENT, BUT DO SHOW SOME DISCREPANCIES
IN BOTH THE PLACEMENT AND STRENGTH OF THE AFOREMENTIONED
SYSTEMS, LEADING TO A MODERATE (60%) CONFIDENCE IN THE OVERALL
FORECAST.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 1157 AM MDT WED SEP 10 2025
VFR CONDITIONS EXPECTED OVER THE NEXT 24 HOURS, OUTSIDE OF ANY
THUNDERSTORMS THAT MOVE DIRECTLY OVER SITES WHICH COULD BRING
BRIEF MVFR OR LOWER CONDITIONS. STORMS ALREADY APPEARING THIS
AFTERNOON, AND WILL CONTINUE THROUGH THE LATE EVENING HOURS
BEFORE DISSIPATING. ALL SITES HAVE A POSSIBILITY OF A PASSING
STORM, THOUGH PROBABILITIES ARE TOO LOW FOR KRWL/KSNY TO INCLUDE
AT THIS TIME. STORMS MAY ALSO PRODUCE GUSTY AND VARIABLE WINDS.
CLOUD DECKS GENERALLY MID LEVEL, AROUND 10K FEET.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...SF
LONG TERM...CG
AVIATION...CG
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