580
FXUS65 KCYS 090806
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
206 AM MDT WED SEP 9 2026
KEY MESSAGES
- DRY CONDITIONS EXPECTED THROUGH THURSDAY ALONGSIDE CRITICAL
FIRE WEATHER CONDITIONS. COOLER ON WEDNESDAY WITH TEMPERATURES
WARMER AGAIN ON THURSDAY AND FRIDAY.
- MOISTURE AND COOLER TEMPERATURES RETURN FRIDAY THROUGH THE
WEEKEND, WITH ANOTHER SHOT OF COOLER AIR TO START NEXT WEEK.
SHORT TERM /THROUGH FRIDAY/
ISSUED AT 200 AM MDT WED SEP 9 2026
NEXT COUPLE OF DAYS OF THE FORECAST LOOK TO BE MOSTLY BENIGN
ASIDE FROM CRITICAL FIRE WEATHER CONDITIONS UNDER DRY ZONAL FLOW
ALOFT THAT WILL TRANSITION TO A TRANSIENT RIDGE ON THURSDAY.
WITH THE COLD FRONT HAVING PASSED THROUGH THE REGION, LOOK FOR
TEMPERATURES NEAR NORMAL WITH HIGHS IN THE 70'S TO LOW 80'S, A
NICE RESPITE FROM THE CONTINUOUS SUMMER WE'VE BEEN EXPERIENCING.
MEANWHILE SURFACE PRESSURE GRADIENTS WILL PROMOTE BREEZY WINDS,
MOSTLY IN THE WESTERN SECTIONS OF OUR CWA, AND WITH DAYTIME RH
VALUES DESCENDING INTO THE TEENS TO SINGLE DIGITS, A RED FLAG
WARNING HAS BEEN ISSUED FOR MANY OF THESE ZONES. AND WITH
OVERNIGHT RECOVERIES VERY LOW, ONLY PEAKING IN THE 20-30% RANGE,
THIS WARNING EXTENDS OVERNIGHT INTO THURSDAY, WHERE RH VALUES
SHOULD BE EVEN LOWER AND MORE WIDESPREAD (LOW SINGLE DIGITS TO
LOW TEENS). OUR WINDS MAY ALSO BE A BIT MORE WIDESPREAD AS
COMPARED TO TODAY, SO THESE PRODUCTS MAY NEED TO BE EXTENDED
FURTHER TOMORROW. WITH TRANSIENT RIDGING OVER THE AREA, LOOK
FOR TEMPERATURES TO JUMP BACK UP AS WELL TO COINCIDE WITH THE DRY
CONDITIONS, AS HIGHS REACH BACK INTO THE 80'S TO 90'S,
PARTICULARLY EAST OF THE LARAMIE RANGE. FRIDAY WE'LL SEE FLOW
BEGIN TO TURN BACK WESTERLY TO SOUTHWESTERLY WITH A PAIR OF
SURFACE TROUGHS MOVING ACROSS THE REGION AND A COLD FRONT
KNOCKING ON OUR DOORSTEP. THIS WILL BEGIN TO RETURN MOISTURE TO
THE AREA, WITH A FEW SHOWERS AND STORMS LIKELY FIRING OFF OF
THESE BOUNDARIES DURING THE LATE AFTERNOON AND INTO THE EVENING.
FAVORABLE INSTABILITY WILL REMAIN JUST EAST OF THE CWA, AND
WITH CONDITIONS REMAINING MOSTLY DRY AT THE SURFACE, MOST OF
THIS WILL LIKELY BE DRY IN NATURE PRODUCING VIRGA AND THE
ATTENDANT GUSTY SHOWERS OR DRY STORMS, SUPPORTED BY INVERTED V
PROFILES. BUT THIS SHOULD BE THE THE PRECURSOR TO OUR WEEKEND,
WHEN FURTHER MOISTURE RETURNS AND WE COOL OFF YET AGAIN.
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
ISSUED AT 200 AM MDT WED SEP 9 2026
MOVING INTO THE WEEKEND, A COLD FRONT WILL DROP ACROSS THE AREA
ON SATURDAY, LIFT BACK UP AS A WARM FRONT INTO SUNDAY, AND THEN
DROP RIGHT BACK THROUGH BY MONDAY. THIS WILL BE IN RESPONSE TO A
DEEP LOW ALOFT MOVING OVER THE PACNW AND THEN ACROSS OUR AREA
THROUGH EARLY NEXT WEEK. WITH FLOW REMAINING SOUTHWESTERLY,
MONSOONAL MOISTURE WILL CONTINUE TO INCREASE WITH PWAT VALUES
125-150% OF NORMAL, POSSIBLY EVEN NEARING 175% FOR PORTIONS OF
THE NEBRASKA PANHANDLE SUNDAY INTO MONDAY. BETTER INSTABILITY
AND SHEAR WILL ALSO SUPPORT STRONGER STORM ACTIVITY AND MAY
SIGNAL THE RETURN OF STRONG TO SEVERE STORMS. INTO MONDAY
MOISTURE WILL BEGIN TO EXIT ALONG WITH THESE SYSTEMS, BUT WE
SHOULD EXPERIENCE THE COOLEST DAY WE'VE SEEN SINCE THE START OF
SUMMER, WITH HIGHS NOT EXPECTED TO PEAK OUTSIDE OF THE 60'S TO
70'S, A SIGN OF FALL TO COME. BUT INTO TUESDAY RIDGING WILL
BEGIN TO REBOUND, THIS TIME ACROSS THE SOUTHEASTERN US, WITH A
SLIGHT WARMING TREND TO END THE LONG TERM.
AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
ISSUED AT 1055 PM MDT TUE SEP 8 2026
WEST TO NORTHWEST FLOW ALOFT WILL CONTINUE THROUGH WEDNESDAY NIGHT.
DRIER AIR WILL BRING A TEMPORARY LULL IN RECENT THUNDERSTORM ACTIVITY
ACROSS WESTERN NEBRASKA AND SOUTHEAST WYOMING.
HAZARDS/WEATHER TRENDS: VFR CONDITIONS WILL PREVAIL OVER THE NEXT 24
HOURS WITH MOSTLY CLEAR SKIES. BREEZY CONDITIONS ARE EXPECTED AT KRWL,
KLAR, AND KCYS WITH GUSTS OF 25 TO 30 KNOTS POSSIBLE AFTER 17Z
WEDNESDAY.
CYS WATCHES/WARNINGS/ADVISORIES
WY...RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM MDT THURSDAY
FOR WYZ419>422-425-427.
NE...NONE.
SHORT TERM...CG
LONG TERM...CG
AVIATION...TT
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