339
FXUS65 KCYS 040004
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
505 PM MST MON NOV 3 2025
KEY MESSAGES
- WINDY, MILD, AND DRY CONDITIONS EXPECTED THROUGHOUT MUCH OF
THE WEEK DUE TO A ZONAL FLOW PATTERN.
- STRONG WINDS AND COOLING TEMPERATURES EXPECTED DURING THE
LATER HALF OF THE WEEK AND INTO THE WEEKEND.
SHORT TERM /THROUGH TUESDAY NIGHT/
ISSUED AT 250 PM MST MON NOV 3 2025
A CHALLENGING AND UNCERTAIN WIND FORECAST IS EXPECTED OVER THE NEXT
30 HOURS OR SO AS A SHORTWAVE MOVES ACROSS THE AREA AND A STRONG 250
MB JET SETS UP JUST TO THE NORTH OF THE CWA. THIS UPPER-LEVEL
SHORTWAVE WILL ENTER THE CWA THIS EVENING, CAUSING MSLP GRADIENTS TO
TIGHTEN. A SURFACE HIGH DEVELOPING OVER WESTERN COLORADO AND A
SURFACE TROUGH OVER THE LARAMIE RANGE WILL STEEPEN GRADIENTS WEST OF
THE LARAMIE RANGE, INCREASING WINDS IN AND AROUND THE ARLINGTON
ZONE. CAG TO CPR 850 AND 700 MB HEIGHT GRADIENTS WILL ALSO SEE AN
UPTICK TONIGHT INTO TOMORROW, BUT NOT ENOUGH TO IMMEDIATELY SIGNAL
HIGH WINDS. REGARDLESS, STEEPENING GRADIENTS WILL CAUSE WINDS ALOFT
TO INCREASE TO ABOUT 50 KTS OVER THE USUAL SOUTHEAST WYOMING WIND
PRONES. VERY STRONG SUBSIDENCE WILL ALSO DEVELOP OVERNIGHT, BUT WILL
LIKELY NOT BE CO-LOCATED WITH THE STRONGEST WINDS ALOFT PER THE GFS.
DESPITE THIS, IN-HOUSE GUIDANCE STILL SHOWS ELEVATED POTENTIALS FOR
HIGH WINDS IN THE WIND PRONES OVERNIGHT. DECIDED TO HOLD OFF ON
ISSUING ANY HIGH WIND HEADLINES TONIGHT, MAINLY BECAUSE OF THE
POSITION OF THE SURFACE TROUGH. BOTH THE GFS AND NAM SHOW THE TROUGH
OVER THE LARAMIE RANGE, WHICH TYPICALLY DOESN'T BODE WELL FOR HIGH
WINDS AT BORDEAUX OR THE SOUTH LARAMIE RANGE AND FOOTHILLS. HOWEVER,
DID MAKE SURE TO AT LEAST INCREASE WINDS AND WIND GUSTS IN THE
FORECAST TO JUST UNDER HIGH WIND CRITERIA AS IT WILL STILL BE VERY
WINDY OVERNIGHT.
HIGH WIND POTENTIALS CONTINUE INTO THE DAY TUESDAY WITH IN-HOUSE
GUIDANCE PREDICTING HIGH WINDS DESPITE ONLY SHOWING ABOUT 40
PERCENT PROBABILITIES FOR HIGH WINDS ACTUALLY OCCURRING IN THE
WIND PRONES. A 250 MB JET WILL PUSH INTO NORTHERN WYOMING ON
TUESDAY, FORCING A COLD FRONT DOWN INTO THE CWA DURING THE
AFTERNOON AND EVENING HOURS. THIS FRONT WILL EFFECTIVELY WEAKEN
MSLP GRADIENTS CAUSING WINDS ALOFT TO ALSO WEAKEN. STRONG
SUBSIDENCE WILL STILL EXIST, SO WIND GUSTS OVER 50 MPH ARE STILL
LIKELY FOR THE WIND PRONES, HOWEVER, GIVEN THE SET UP, DID NOT
HAVE THE CONFIDENCE TO ISSUE ANY HEADLINES. GIVEN THE STRONG
WESTERLY WINDS EXPECTED TOMORROW, TEMPERATURES WILL BE QUITE
MILD DUE TO DOWNSLOPING. NBM GUIDANCE SEEMED TOO LOW, SO WENT
AHEAD AND RAISED TEMPERATURES. HIGH TEMPERATURES IN THE 60S AND
70S ARE EXPECTED, WITH A FEW LOCATIONS COMING WITHIN A FEW
DEGREES OF THEIR RECORD HIGHS. HOWEVER, THERE IS A CHANCE
TEMPERATURES DO NOT GET AS HIGH AS FORECAST DUE TO MOUNTAIN WAVE
CLOUDS OBSTRUCTING THE SUN DURING DAYTIME HEATING HOURS.
TEMPERATURES WILL COOL OFF AND WINDS WILL EASE TUESDAY NIGHT
BEHIND THE COLD FRONT.
LONG TERM /WEDNESDAY THROUGH SUNDAY/
ISSUED AT 250 PM MST MON NOV 3 2025
THE LONG TERM WILL BE ACTIVE AS WE SEE MULTIPLE DAYS IN A ROW
OF STRONG TO HIGH WINDS AS SEVERAL SYSTEMS MOVE ACROSS THE
REGION, ALSO COOLING US BACK DOWN FROM OUR ABOVE NORMAL
TEMPERATURES BACK TO NEAR NORMAL BY THE WEEKEND. WEDNESDAY
STARTS WITH A QUICK MOVING SHORTWAVE THAT WILL BRING BREEZY
CONDITIONS AND LOWER TEMPERATURES COMPARED TO TUESDAY, BUT WE
ARE EXPECTED TO REMAIN SEVERAL DEGREES ABOVE NORMAL ACROSS THE
CWA. THE REAL STORY FOR MORE ACTIVE CONDITIONS STARTS INTO
THURSDAY MORNING AS A DEEPER TROUGH SWINGS IN AND SHIFTS RIDGING
OUT OF OUR AREA. THIS WILL CAUSE TEMPERATURES WEST OF THE
LARAMIE RANGE TO DROP BACK DOWN TO NEAR NORMAL WITH HIGHS IN THE
UPPER 40'S TO LOW 50'S, BUT LOCATIONS EAST OF THIS WILL REMAIN
WARM AS WE SEE 50'S TO MID 60'S LINGERING THROUGH FRIDAY. BUT
THE ENHANCED PRESSURE GRADIENT FROM THIS SYSTEM WILL PROMOTE
WIDESPREAD 700MB WINDS IN THE 50 KNOT RANGE WITH FAVORABLE
DOWNWARD OMEGA VALUES BRINGING THESE SPEEDS DOWN TO THE SURFACE.
AND THEN OVER THE WEEKEND THE WINDS DON'T STOP AS A QUICK
MOVING UPPER LEVEL PACIFIC LOW THEN SWINGS THROUGH, CONTINUING
HIGH WINDS THROUGH SATURDAY AND ALSO FINALLY DROPPING
TEMPERATURES ACROSS THE WHOLE CWA BACK TO NEAR NORMAL. MEANWHILE
THIS PATTERN SHOULD SET OFF SOME LIGHT PRECIPITATION ON
THURSDAY AND AGAIN FRIDAY, BUT WITH A LACK OF STRONGER MOISTURE
AND FORCING, EXPECT ANY SHOWERS THAT CAN OCCUR TO BE LIMITED TO
THE HIGH TERRAIN AND MOUNTAINS, WITH MINIMAL ACCUMULATIONS OF
SNOW AND/OR RAIN/SNOW MIX.
AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/
ISSUED AT 505 PM MST MON NOV 3 2025
A SUBTLE SHORTWAVE DISTURBANCE ALOFT WILL MOVE EAST OF THE REGION
THIS EVENING WITH GRADUAL DECREASING CLOUDS. CLEARING SKIES ARE
EXPECTED BY 06Z. OTHERWISE, BREEZY CONDITIONS ARE EXPECTED THROUGH
TONIGHT FOR MOST TERMINALS.
HAZARDS/WEATHER TRENDS: VFR CONDITIONS WILL PERSIST TONIGHT AND
TUESDAY. MAIN AVIATION CONCERN WILL BE SURFACE WINDS AND LLWS. KEPT
LLWS IN FOR TERMINALS THAT SEE WINDS DECOUPLE FROM WINDS ALOFT.
OTHERWISE, GUSTS UP TO 25 MPH FROM THE SOUTH OR SOUTHWEST WILL
CONTINUE. WINDS WILL INCREASE AFTER 17Z TUESDAY WITH GUSTS UP TO 35
KNOTS POSSIBLE.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...SF
LONG TERM...CG
AVIATION...TJT
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