837
FXUS65 KCYS 152141
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
341 PM MDT WED JUL 15 2026
KEY MESSAGES
- HOT, DRY AND BREEZY CONDITIONS EXPECTED THROUGH THE END OF THE
WEEK.
- MOSTLY DRY WEATHER WILL CONTINUE FOR FRIDAY AND SATURDAY,
WITH DAILY INCREASING CHANCES FOR AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS FOR SUNDAY THROUGH WEDNESDAY DUE TO
MONSOONAL MOISTURE SPREADING EASTWARD ACROSS SOUTHEAST WYOMING
AND WESTERN NEBRASKA.
- MAXIMUM TEMPERATURES WILL REMAIN HOT FRIDAY AND SATURDAY,
WITH A DECENT COOLING TREND IN HIGH TEMPERATURES FOR SUNDAY
INTO MIDWEEK DUE TO INCREASING CLOUD COVER AND INCREASING
SHOWER AND THUNDERSTORM COVERAGE.
SHORT TERM /THROUGH THURSDAY NIGHT/
ISSUED AT 140 PM MDT WED JUL 15 2026
SHORT TERM REMAINS MUCH OF THE SAME AS A RIDGE OF HIGH PRESSURE
ALOFT CONTINUES TO SIT OVER THE REGION WITH A VERY WEAK SURFACE
FRONT ASSOCIATED WITH A TROUGH MOVING INTO THE CWA THROUGH
THURSDAY NIGHT. AS THIS WEAK BOUNDARY MAKES ITS WAY INTO OUR
AREA, SOME HIGH RESOLUTION GUIDANCE IS TRYING TO FORM SOME
INITIATION OFF OF IT AND BRING A CHANCE FOR THUNDERSTORMS, BUT
WITH INCREDIBLY DRY SURFACE PROFILES PRODUCING INVERTED V
SOUNDINGS AND DAYTIME DEWPOINTS IN THE 40'S, MORE THAN LIKELY IF
ANYTHING CAN FORM OFF OF THIS BOUNDARY IT'S GOING TO BE HIGH
BASED WITH VIRGA STRUGGLING TO REACH THE SURFACE AS RAIN, AND
THREATENING ONLY DRY LIGHTNING OR A GUSTY OUTFLOW. BUT ASIDE
FROM A COUPLE OF THE HIGH RESOLUTION MODELS, STRUGGLING TO SEE
MUCH IN THE WAY OF MEANINGFUL OR EVEN WEAK PRECIPITATION BEING
POSSIBLE, AND SO HAVE LEFT THE NBM AS IS WITH NO ADDITIONS TO
PRECIPITATION CHANCES AT THIS TIME. OTHERWISE THIS FRONT ISN'T
GOING TO OFFER MUCH IN THE WAY OF RELIEF AS TEMPERATURES ARE
NEARLY IDENTICAL TO TODAY WITH HIGHS IN THE UPPER 80'S TO UPPER
90'S, WITH PERHAPS A DEGREE OR TWO SHAVED OFF WEST OF THE I-25
CORRIDOR, BUT OTHERWISE RELIEF NOT IN SIGHT FROM THIS SUMMER
HEATWAVE. AS FOR HEADLINES, PRESSURE GRADIENTS WILL WEAKEN
ENOUGH THAT WINDS SHOULD LESSEN INTO THURSDAY AND RH VALUES WILL
AT LEAST RISE INTO THE UPPER TEENS TO LOW 20'S, ENOUGH THAT RED
FLAG CONDITIONS WILL BE ALLOWED TO EXPIRE TODAY. HEAT ADVISORY
FOR THURSDAY ALSO FEELS UNNECESSARY WITH ONLY A SITE OR TWO
EXPECTED TO REACH TRIPLE DIGITS, AND SO WILL LET THOSE EXPIRE
THIS EVENING, BUT A NEW HEAT ADVISORY MAY BE NEEDED FOR THE
WEEKEND WHEN TEMPERATURES RISE ONCE AGAIN.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
ISSUED AT 140 PM MDT WED JUL 15 2026
FRIDAY...RIDGING ALOFT REMAINS ENTRENCHED OVER OUR REGION, WHILE
THERE SHOULD BE A SLIGHT INCREASE IN MID LEVEL MONSOONAL MOISTURE,
THOUGH LIKELY NOT ENOUGH MID LEVEL MOISTURE TO INITIATE THUNDERSTORM
DEVELOPMENT, BECAUSE OF THE WARM MID LEVEL 700 MB TEMPERATURES FROM
15 TO 20 CELSIUS, PRODUCING ENOUGH CIN, CONVECTIVE INHIBITION, TO
KEEP POPS NEAR NIL. NEAR PERFECT DAY WEATHERWISE FOR OUTDOOR WEATHER
ACTIVITIES, WITH MAXIMUM TEMPERATURES IN THE MID TO UPPER 80S WEST
OF I-25, AND 90S TO NEAR 100 DEGREES EAST OF I-25. PLEASE BE SURE TO
DRINK PLENTY OF WATER AND STAY HYDRATED WHEN OUTDOORS FOR ANY
SIGNIFICANT LENGTH OF TIME.
SATURDAY...WITH THE RIDGE ALOFT REMAINING PARKED OVER WYOMING, AND
WARM MID LEVEL TEMPERATURES PRODUCING ENOUGH CIN, CONVECTIVE
INHIBITION, THIS WILL LIMIT AREAL COVERAGE TO ISOLATED TO WIDELY
SCATTERED SHOWERS AND THUNDERSTORMS OVER OUR SNOWY AND SIERRA MADRE
RANGES IN THE AFTERNOON, AND OVER MUCH OF CARBON COUNTY INCLUDING
RAWLINS IN THE EVENING...OTHERWISE DRY.
SUNDAY...GFS PROGS THE RIDGE ALOFT OVER THE NORTHERN ROCKIES TO BE
FLATTENED SOMEWHAT WITH ZONAL FLOW DEVELOPING OVER MONTANA AND
NORTHERN WYOMING. A WEAK PERTURBATION, OR SHORTWAVE TROUGH ALOFT,
WILL MOVE ACROSS OUR COUNTIES IN THE AFTERNOON AND EVENING, WITH
MONSOONAL MOISTURE ADVECTING INTO OUR WESTERN COUNTIES WEST OF I-25,
WHERE WE ANTICIPATE SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP
IN THE AFTERNOON WEST OF I-25, WITH THE GREATEST AREAL COVERAGE OVER
THE SNOWY, SIERRA MADRE AND NORTHERN LARAMIE RANGES. SO, MORE
BENEFICIAL RAIN WILL OCCUR. MONSOONAL MOISTURE IS PROGGED TO ADVECT
FURTHER EASTWARD IN THE EVENING, SPAWNING ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS FOR OUR COUNTIES EAST OF I-25, WITH LESSER
COVERAGE OVER THE NEBRASKA PANHANDLE.
MONDAY...MONSOONAL MOISTURE AT LOW AND MID LEVELS INCREASES FURTHER,
AIDING IN ANOTHER INCREASE IN LATE DAY SHOWER AND THUNDERSTORM
COVERAGE, AND BENEFICIAL RAINS, WITH COVERAGE INCREASING TO
SCATTERED, 30 TO 60 PERCENT POPS, WITH THE GREATEST COVERAGE OVER
AND NEAR OUR MOUNTAIN ZONES.
TUESDAY AND WEDNESDAY...THE ZONAL FLOW ALOFT CONTINUES WITH ABUNDANT
MONSOONAL MOISTURE REMAINING OVER OUR CWA, COUNTY WARNING AREA,
HELPING TO PRODUCE SCATTERED TO NUMEROUS SHOWERS AND SCATTERED
THUNDERSTORMS IN THE AFTERNOONS AND EVENINGS WITH MORE BENEFICIAL
RAINFALL, AGAIN WITH THE HIGHEST AREAL COVERAGE OVER OUR SNOWY,
SIERRA MADRE AND LARAMIE RANGES.
AVIATION /18Z TAFS THROUGH 18Z THURSDAY/
ISSUED AT 334 PM MDT WED JUL 15 2026
A PERSISTENT RIDGE ALOFT WILL REMAIN ENTRENCHED ACROSS UTAH,
WYOMING AND COLORADO. AT THE SURFACE, LOW PRESSURE WILL
STRENGTHEN ACROSS NORTHWEST COLORADO BY THIS EVENING, PRODUCING
EAST AND SOUTHEAST UPSLOPE WINDS ALONG AND EAST OF I-25, THEN
OVERNIGHT A MODERATE SOUTHERLY LOW LEVEL JET WILL DEVELOP FOR
WESTERN NEBRASKA FOR THE LATE EVENING AND OVERNIGHT HOURS, WITH
A SURFACE TROUGH OR DISCONTINUITY FROM LARAMIE TO LUSK. THE
RINSE AND REPEAT EAST AND SOUTHEAST WINDS WILL ONCE AGAIN
DEVELOP THURSDAY MORNING.
WYOMING TAFS...HIGH CONFIDENCE IN NEARLY CLEAR VFR CONDITIONS.
SCATTERED HIGH BASED CUMULUS DEVELOPMENT IS EXPECTED THIS
AFTERNOON AND EVENING MAINLY WEST OF I-25. GUSTY WINDS FROM 25
TO 30 KNOTS WILL OCCUR THROUGH EARLY EVENING, THEN DIMINISH
OVERNIGHT. WIND GUSTS WILL INCREASE AGAIN TO 20 TO 25 KNOTS AT
RAWLINS AND CHEYENNE AFTER MID MORNING THURSDAY.
NEBRASKA TAFS...HIGH CONFIDENCE IN CLEAR SKIES AND VFR THROUGH
THE PERIOD, EXCEPT FOR SOME HIGH BASED CUMULUS CLOUDS THROUGH
SUNSET. GUSTY WINDS OF 25 TO 30 KNOTS THROUGH EARLY EVENING,
WITH WINDS DECREASING AFTER SUNSET, THEN SOUTH AND SOUTHEAST
WINDS INCREASING AGAIN TO GUSTS OF 25 TO 35 KNOTS FROM 06Z TO
14Z, BEFORE WINDS DECREASE AFTER DAYBREAK THURSDAY.
CYS WATCHES/WARNINGS/ADVISORIES
WY...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR WYZ417>420-
423-427-430>433.
HEAT ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR WYZ101-102-107-
108-118-119.
NE...RED FLAG WARNING UNTIL 8 PM MDT THIS EVENING FOR NEZ434>437.
HEAT ADVISORY UNTIL MIDNIGHT MDT TONIGHT FOR NEZ002-003-
019>021-054-055-095-096.
SHORT TERM...CG
LONG TERM...RUBIN
AVIATION...RUBIN
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