680
FXUS65 KCYS 012346
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
546 PM MDT SAT AUG 1 2026
KEY MESSAGES
- A HEAT WAVE WILL BUILD INTO THE AREA SATURDAY THROUGH MONDAY,
PRODUCING NEAR RECORD HIGH TEMPERATURES FOR SUNDAY.
- ELEVATED TO CRITICAL FIRE WEATHER CONDITIONS ARE EXPECTED
SUNDAY AND MONDAY.
- SOME RELIEF OF THE HEAT IS POSSIBLE DURING THE MIDDLE OF NEXT
WEEK AS A CANADIAN COLD FRONT MOVES TOWARDS THE FRONT RANGE.
SHORT TERM /THROUGH SUNDAY NIGHT/
ISSUED AT 130 PM MDT SAT AUG 1 2026
HIGH PRESSURE RIDGING REMAINS FIRMLY IN PLACE TODAY, KEEPING OUR
TEMPERATURES WARM WITH MINIMAL CONCERNS OUTSIDE OF THE HOT
WEATHER, AT LEAST FOR TODAY. THIS AFTERNOON AND TONIGHT, WHILE
TEMPERATURES AREN'T EXCEPTIONALLY HOT, EXPECT HIGHS TO MAX OUT
THIS AFTERNOON IN THE 90'S ACROSS MOST OF OUR CWA, THOUGH A
ROGUE 100 COULD OCCUR FOR THE UPPER PANHANDLE OR FAR EASTERN
WYOMING. OVERNIGHT LOWS SHOULD REMAIN COOL ENOUGH, DIPPING INTO
THE UPPER 50'S TO LOW 70'S. BUT THEN MOVING INTO SUNDAY WE'LL
SEE A SCORCHER OF A DAY ACROSS THE ENTIRE REGION. HIGH
TEMPERATURES ARE WIDESPREAD IN THE MID 90'S TO UPPER 100'S, AT
OR ABOVE THE 99TH PERCENTILE FOR THE ENTIRE REGION. THIS HAS
PROMPTED A HEAT ADVISORY FOR A MAJORITY OF THE CWA, VALID DURING
THE DAY THROUGH THE EVENING. ALSO OF NOTE WILL BE THE DRY
CONDITIONS COUPLED WITH BREEZY WINDS, LEADING TO AN EXPECTED
CRITICAL FIRE WEATHER ENVIRONMENT. PRESSURE GRADIENTS WILL BE ON
THE RISE THANKS TO A TROUGH OVERTAKING THE PACIFIC NORTHWEST
AND MOVING EASTWARDS TOWARDS OUR REGION, CAUSING SURFACE FLOW TO
STRENGTHEN AND BRING ELEVATED WINDS. THE STRONGEST WINDS WILL
BE PRIMARILY ALONG OUR EAST AND WEST BORDERS, WITH A RED FLAG
WARNING IN EFFECT FOR TOMORROW FOR THE NEBRASKA PANHANDLE, AND
A TWO-DAY RED FLAG WARNING FOR OUR FAR WESTERN ZONES OF CARBON
COUNTY AS THIS ENVIRONMENT PERSISTS INTO MONDAY ALONGSIDE POOR
OVERNIGHT RECOVERIES OF 20 TO 30%. FINALLY, SOME HIGH RESOLUTION
GUIDANCE INDICATES THE POTENTIAL FOR SOME CLOUDS AND EVEN A
VERY LOW RISK OF A SHOWER OR TWO COMING OFF OF THE MOUNTAINS
TOMORROW, BUT WITH A VERY DRY LOW LEVEL ENVIRONMENT PRODUCING
STOUT INVERTED V SIGNALS AND SOME MODEST DCAPE, LIKELY THESE
WILL BE NOTHING MORE THAN WEAK VIRGA WITH POTENTIAL FOR SOME
GUSTY OUTFLOW.
LONG TERM /MONDAY THROUGH SATURDAY/
ISSUED AT 130 PM MDT SAT AUG 1 2026
THE WORK WEEK WILL BEGIN UNDER ZONAL FLOW ALOFT AS THE HIGH
AMPLITUDE, POSITIVELY-TILTED RIDGE THAT WAS RESPONSIBLE FOR THE
ANOMALOUS WARMTH OVER THE WEEKEND PROGRESSES TOWARDS THE EAST. A
COLD FRONT IS EXPECTED TO PUSH ACROSS SE WYOMING AND WESTERN
NEBRASKA SOMETIME MONDAY MORNING, WHICH WILL INTRODUCE A COOLER AIR
MASS RELATIVE TO THE NEAR RECORD-BREAKING TEMPERATURES THAT ARE
EXPECTED ON SUNDAY. WITH PWAT LARGELY BELOW THE 50TH PERCENTILE PER
LONG RANGE ENSEMBLE GUIDANCE AND ANY LARGE-SCALE FORCING FOR ASCENT,
PRECIPITATION CHANCES LOOK MINIMAL AT THIS TIME. THE MAIN NOTICEABLE
CHANGE WILL BE THE 10-15 DEGREE DROP IN HIGH TEMPERATURES, WITH
LOCATIONS WEST OF THE I-25 CORRIDOR SEEING HIGHS IN THE MID TO UPPER
80S, AND OUR NEBRASKA COUNTIES BARELY PEAKING ABOVE 90 DEGREES.
NEEDLESS TO SAY, THESE TEMPERATURES ARE STILL RUNNING AT OR EVEN
SLIGHTLY ABOVE AVERAGE. GUSTY WINDS ARE ALSO POSSIBLE ON MONDAY, AS
GRADIENT FLOW INCREASES THANKS TO LEE CYCLOGENESIS OCCURRING TO
OUR SOUTH OVER COLORADO COMBINED WITH A SURFACE HIGH BUILDING
IN BEHIND THE COLD FRONT. WITH 50TH PERCENTILE WIND GUSTS
RANGING FROM 25-30 MPH, MINIMUM RH VALUES DECREASING TO 15-25%
DURING THE AFTERNOON, AND PLENTY OF DRY FUELS WITH THE D3-D4
DROUGHT CONDITIONS, FIRE WEATHER CONCERNS PERSIST INTO EARLY
NEXT WEEK DESPITE THE SLIGHTLY COOLER TEMPERATURES.
ON TUESDAY, A SECONDARY SHOT OF COOLER AIR WILL EXTEND DOWN INTO OUR
AREA AS A SURFACE ANTICYCLONE BECOMES ESTABLISHED TO OUR NORTH OVER
THE DAKOTAS. WITH WEAK ISENTROPIC DESCENT/COLD ADVECTION BEHIND THE
FRONT, HIGH TEMPERATURES ARE EXPECTED TO BE 10-15 DEGREES COOLER
THAN MONDAY'S HIGHS, WITH MANY LOCATIONS STRUGGLING TO REACH
THE 80 DEGREE MARK. THIS IS A MUCH WELCOME CHANGE TO WHAT WE
HAVE SEEN SO FAR THIS SUMMER, BUT DON'T GET TOO EXCITED
CONSIDERING TRENDS INTO NEXT WEEKEND, AS I'M SURE MANY OF YOU
ARE BURNING TO KNOW...
EXPECT A SLIGHT INCREASE IN HIGH TEMPERATURES ON WEDNESDAY AS A 594
DAM MID-LEVEL RIDGE BUILDS ACROSS THE DESERT SOUTHWEST, WITH HIGH
TEMPERATURES AT OR SLIGHTLY BELOW CLIMATOLOGY (AVERAGE HIGH FOR
CHEYENNE ON WEDNESDAY IS 84 DEGREES). WE STILL LOOK TO REMAIN MOSTLY
DRY AS SE WYOMING/W NEBRASKA REMAIN UNDER WNW FLOW ALOFT, WHICH
ISN'T EXACTLY FAVORABLE FOR MONSOONAL MOISTURE TRANSPORT FROM THE
SOUTHWEST. THE RIDGE (AS DOES THE HEAT) BUILDS ON THURSDAY, WITH
ENSEMBLE GUIDANCE SUGGESTING MEDIAN HIGH TEMPERATURES IN THE LOW TO
MID-90S EAST OF THE LARAMIE RANGE, AND UPPER 80S TO THE WEST. WITH
PWAT PROGGED AROUND 15-25% RELATIVE TO CLIMATOLOGY, WE LOOK TO
REMAIN MOSTLY DRY. THE TREND CONTINUES ON FRIDAY INTO THE WEEKEND
(UNFORTUNATELY), AS 500 MB HEIGHTS RISE AND THE RIDGE REMAINS WELL-
ESTABLISHED OVER NEVADA AND ARIZONA. UNDER QUASI-ZONAL FLOW ALONG
THE NORTHERN PERIPHERY OF THE RIDGE, THERE AREN'T ANY STRONG SIGNALS
FOR ANY SUBSTANTIAL MONSOONAL MOISTURE MOVING INTO OUR AREA. SORRY
FOR SOUNDING LIKE A BROKEN RECORD, OR FOR ADVERTISING THE POTENTIAL
FOR MORE HEAT-RELAATED RECORDS BEING BROKEN, WE LOOK TO REMAIN HOT
AND DRY INTO LATER NEXT WEEK.
AVIATION /00Z TAFS THROUGH 00Z MONDAY/
ISSUED AT 530 PM MDT SAT AUG 1 2026
VFR CONDITIONS ARE EXPECTED THROUGHOUT THE FORECAST PERIOD.
WINDS ARE GENERALLY BELOW 15 KNOTS AT ALL TERMINALS. STARTING AT
02Z A NOCTURNAL LOW LEVEL JET WILL DEVELOP OVER MUCH OF THE
AREA. WINDS OF 20-30 KNOTS OUT OF THE SOUTH TO SOUTHEAST CAN BE
EXPECTED. THERE MAY BE SOME LOW LEVEL WIND SHEAR CONCERNS AT
KBFF STARTING AROUND 08Z THROUGH 11Z THAT MAY BE INCLUDED AT THE
06Z TAF. HIGH LEVEL CLOUD COVERAGE WILL INCREASE THROUGH THE
NIGHT. STARTING AROUND 08Z THROUGH EARLY AFTERNOON WINDS AT THE
WYOMING TERMINALS WILL BE CALM AND VARIABLE. CONTINUED VFR CONDITIONS
OF DIURNAL SCATTERED CUMULUS CLOUDS AND WINDS GENERALLY BELOW
25 KNOTS THROUGH LATE AFTERNOON.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HEAT ADVISORY FROM 11 AM TO 9 PM MDT SUNDAY FOR WYZ101-102-104-
107>109-111-118-119.
RED FLAG WARNING FROM NOON SUNDAY TO 9 PM MDT MONDAY FOR
WYZ421>423.
NE...HEAT ADVISORY FROM 11 AM TO 9 PM MDT SUNDAY FOR NEZ002-003-
019>021-054-055-095-096.
RED FLAG WARNING FROM NOON TO 9 PM MDT SUNDAY FOR NEZ434>437.
SHORT TERM...CG
LONG TERM...NB
AVIATION...RV
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