841
FXUS65 KCYS 111923
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
123 PM MDT SAT JUL 11 2026
KEY MESSAGES
- STRONG RIDGING ALOFT WILL PRODUCE A DRY AND HOT PERIOD FOR
TODAY THROUGH TUESDAY, WITH THE PRIMARY CHALLENGES BEING THE
ABOVE NORMAL HEAT AND FIRE WEATHER CONDITIONS.
- ISOLATED HIGH-BASED THUNDERSTORMS POSSIBLE ON WEDNESDAY
THROUGH THE END OF THE WEEK, ALONG WITH A SLOW COOLING TREND.
TEMPERATURES WILL REMAIN ABOVE NORMAL THOUGH.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED AT 123 PM MDT SAT JUL 11 2026
AN UPPER-LEVEL RIDGE WILL BECOME DOMINANT OVER THE REGION TODAY,
EXPECT ALL LEVELS INCLUDING THE SURFACE, TO DRY OUT. THIS WILL
BRING SOME GOOD AND SOME BAD. THE GOOD, EXPECT A BEAUTIFUL SUNNY
AFTERNOON, AS EVIDENT ON LATEST SATELLITE IMAGERY, WITH AMPLE
HEATING AS HIGHS SOAR INTO THE 90S TO NEAR 100 FOR A FEW
LOCATIONS ACROSS OUR NORTHERN FORECAST COUNTIES. THE BAD, THIS
HEAT COUPLED WITH MIN RH VALUES TANKING TO AROUND 15% ACROSS
SOUTHEAST WYOMING AND TO AROUND 20% FOR THE NEBRASKA PANHANDLE,
MAKES THE ENVIRONMENT PRIME FOR ELEVATED FIRE WEATHER
CONDITIONS/CONCERNS. THEREFORE, WE HAVE A FIRE WEATHER WATCH IN
PLACE THROUGH SUNDAY MORNING. HI-RES GUIDANCE, SUCH AS THE NAM
NEST, TRIES TO SHOW SOME WIDELY SCATTERED SHOWER DEVELOPMENT
THIS AFTERNOON. HOWEVER, DUE TO THE CURRENT ENVIRONMENT WE ARE
IN, THIS MAY BE A LITTLE AGGRESSIVE AND NOTHING IN FACT MAY
TRANSPIRE. RINSE AND REPEAT FOR SUNDAY, WITH THE UPPER- LEVEL
RIDGE CONTINUING TO DOMINATE, DRY CONDITIONS WILL CONTINUE AND
THE FIRE WEATHER WATCH THAT IS OUT WILL BE UPGRADED TO A RED
FLAG WARNING FROM NOON SUNDAY INTO MONDAY. THIS IS IN PART DUE
TO OUR SURFACE GRADIENT TIGHTENING, RESULTING IN WINDS BECOMING
A TAD GUSTY TO AROUND 25 MPH. THE 'WARM' DAYS WILL CONTINUE AS
LOWS ONLY DIP INTO THE 60S AND AS SUCH, THEREFORE THE HEAT
ADVISORY WE ARE UNDER WILL EXTEND INTO THE LONG TERM PERIOD AS
HIGHS CONTINUE TO SOAR INTO AND THROUGH THE 90S, WITH MANY
LOCATIONS POSSIBLY HITTING THE CENTURY MARK.
LONG TERM /MONDAY THROUGH FRIDAY/
ISSUED AT 123 PM MDT SAT JUL 11 2026
THE WEATHER OVER THE MEDIUM TO LONG RANGE WILL BE DOMINATED BY
THE QUASI-STATIONARY UPPER LEVEL HIGH, FORECAST TO REMAIN OVER
THE SOUTH-CENTRAL TO CENTRAL UNITED STATES, INCLUDING THE ROCKY
MOUNTAIN REGION. TO PUT IT IN PERSPECTIVE, MODELS SHOW THE
POSITION OF THE UPPER LEVEL HIGH (CENTER) DRIFTING WESTWARD BY A
FEW HUNDRED MILES FROM MONDAY TO NEXT SATURDAY. THEREFORE, NOT
EXPECTING CONDITIONS TO CHANGE TOO MUCH THROUGH NEXT WEEK.
FOR EARLY IN THE WEEK, BROAD CENTER OF THE 600DM UPPER LEVEL
HIGH WILL BE GENERALLY LOCATED IN THE CENTRAL ROCKY MOUNTAIN
REGION EXTENDING NORTHEAST INTO THE GREAT LAKES REGION. GFS AND
ECMWF STANDARDIZED 500MB ANOMALIES SHOW BETWEEN 1-3 SD'S ABOVE
AVERAGE...WHICH IS PRETTY IMPRESSIVE SINCE WE'RE CURRENTLY
ENTERING THE HOTTEST WEEK OF THE YEAR...CLIMATOLOGICALLY
SPEAKING. FORECAST HIGH TEMPERATURES WILL BE 90S FOR MOST OF
SOUTHEAST WYOMING, INCLUDING THE HIGH VALLEYS WEST OF THE
LARAMIE RANGE. FOR WESTERN NEBRASKA, 95 TO 105 EXPECTED EACH
DAY. THERE MAY BE SOME SILVERING LINING FOR THE SOUTH FACING
RIDGES. DUE TO SOUTH TO SOUTHEASTERLY WINDS, SOME LOCALIZED
UPSLOPE MAY PREVENT TEMPERATURES FROM CLIMBING EVEN HIGHER. KEPT
TEMPERATURES A FEW DEGREES COOLER (COMPARED TO THE SURROUNDING
AREAS) IN THESE LOCATIONS, WHICH INCLUDE CHEYENNE, KIMBALL,
SIDNEY, ALLIANCE, AND LUSK. HOWEVER, ANY WESTERLY WIND SHIFT OR
LIGHT AND VARIABLE WINDS WILL RESULT IN A RAPID WARM-UP.
AS WE HEAD INTO LATER IN THE WEEK, CENTER OF THE UPPER LEVEL
HIGH WILL DRIFT OVERHEAD, AND EVEN RETROGRADE WESTWARD A BIT.
ALTHOUGH WINDS WILL REMAIN OUT OF THE SOUTHEAST, OR SHIFT INTO
THE EAST DURING THIS TIME, WIND SPEEDS WILL DECREASE OR BECOME
LIGHT AND VARIABLE. THIS MAY ACTUALLY LEAD TO THE HOTTEST
TEMPERATURES OVER THE SOUTH FACING RIDGES. OTHERWISE,
TEMPERATURES WILL BE A FEW DEGREES COOLER ACROSS MOST OF THE
AREA...ALTHOUGH IT WILL BE HARDLY NOTICEABLE. ENSEMBLES AND NBM
75TH TO 90TH PERCENTILE SHOW HIGH TEMPERATURES ONLY A FEW
DEGREES HIGHER THAN THE CURRENT FORECAST, SO KEPT HIGH
TEMPERATURES CLOSE TO THE 50TH PERCENTILE OF THE NBM. LOW
CONFIDENCE ON ANY PRECIPITATION DURING THIS TIME. SUBTROPICAL
MONSOON MOISTURE IS EXPECTED TO CREEP NORTH OUT OF MEXICO AND
THE SOUTHWESTERN US. HOWEVER, THE POSITION OF THE UPPER LEVEL
HIGH OVERHEAD MAY RESULT IN THE MONSOON MOISTURE PLUME OVER
IDAHO, UTAH, AND WESTERN WYOMING. THEREFORE, MOST OF THE MENTION
OF POP AND THUNDERSTORMS WILL BE LIMITED TO THE MOUNTAINS AND
ADJACENT VALLEYS FOR NOW THROUGH NEXT SATURDAY.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1122 AM MDT SAT JUL 11 2026
VFR CONDITIONS WILL PREVAIL ACROSS ALL TERMINALS FOR THE DURATION OF
THIS TAF PERIOD. WINDS WILL GUST UP TO AROUND 20 KNOTS FOR MOST OF
THE DAYLIGHT HOURS TODAY, WINDING DOWN DURING THE EVENING. AS THE
SURFACE GRADIENT TIGHTENS SUNDAY, EXPECT WINDS TO RAMP UP AGAIN
ACROSS ALL SITES WITH SOUTHERLY GUSTS TOPPING OUT AROUND 25 KNOTS BY
ABOUT 18Z SUNDAY.
CYS WATCHES/WARNINGS/ADVISORIES
WY...FIRE WEATHER WATCH THROUGH SUNDAY MORNING FOR WYZ417-418-423-
430>433.
HEAT ADVISORY UNTIL MIDNIGHT MDT TUESDAY NIGHT FOR WYZ101-102-
107-108-118-119.
RED FLAG WARNING FROM NOON SUNDAY TO 8 PM MDT MONDAY FOR
WYZ417>420-423-427-430>433.
NE...FIRE WEATHER WATCH THROUGH SUNDAY MORNING FOR NEZ434.
HEAT ADVISORY UNTIL MIDNIGHT MDT TUESDAY NIGHT FOR NEZ002-003-
019>021-054-055-095-096.
RED FLAG WARNING FROM NOON SUNDAY TO 8 PM MDT MONDAY FOR
NEZ434.
SHORT TERM...RZ
LONG TERM...TJT
AVIATION...RZ
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