375
FXUS65 KCYS 051141
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
540 AM MDT SUN JUL 5 2026
KEY MESSAGES
- SUNDAY WILL BE DRY AS AN UPPER LEVEL RIDGE BUILDS OVER THE
AREA.
- HOT TEMPERATURES EXPECTED SUNDAY AND MONDAY, WITH HIGHS
TOPPING OUT IN THE MID 80S TO MID 90S.
- CONDITIONAL THUNDERSTORM CHANCES RETURN MONDAY THROUGH AT
LEAST THURSDAY IN RESPONSE TO INCREASING MOISTURE.
SHORT TERM /THROUGH MONDAY NIGHT/
ISSUED AT 200 AM MDT SUN JUL 5 2026
ALL MODELS SHOW A QUIET SUNDAY WITH DRY CONDITIONS AS A STRONG
UPPER LEVEL RIDGE AXIS DEVELOPS OVER THE FRONT RANGE AND BUILDS
NORTHWARD. INCREASING 700MB TEMPERATURES EXPECTED WITH FORECAST
VALUES BETWEEN 14C TO 19C ACROSS THE REGION, WARMEST OVER
CENTRAL WYOMING. EXPECT EVEN RAWLINS AND LARAMIE TO SEE HIGHS
IN THE MID TO POSSIBLY UPPER 80S THIS AFTERNOON. WITH DRY AIR
ALOFT MIXING DOWN TO THE SURFACE, RESULTING FROM INCREASING
MIDLEVEL SUBSIDENCE ASSOCIATED WITH THE UPPER LEVEL RIDGE,
EXPECT DAYTIME CONVECTION TO STRUGGLE TO DEVELOP TODAY. HIGH
RESOLUTION MODEL DATA ALL SHOW NO SHOWER OR THUNDERSTORM
ACTIVITY, SO LOWERED POP BELOW 10 PERCENT THROUGH THE EVENING
HOURS. OTHER THAN SOME FAIR WEATHER CU DEVELOPING AND MOVING
EAST, MOSTLY SUNNY SKIES ARE EXPECTED WITH RELATIVELY LIGHT
WINDS BECOMING SOUTH TO SOUTHEASTERLY THROUGH THE AFTERNOON
HOURS. EXPECT A LOW LEVEL JET AROUND 800MB TO DEVELOP ACROSS
THE HIGH PLAINS LATE THIS EVENING, WHICH IS PRETTY TYPICAL THIS
TIME OF THE YEAR IN THE LATE EVENING HOURS, WITH WINDS
INCREASING OUT OF THE SOUTHEAST AFTER SUNSET. MAY SEE SOME GUSTS
OF 30 TO 40 MPH IN AND AROUND THE PINE RIDGE AND THE CHEYENNE
RIDGE.
LOW LEVEL JET WILL DIMINISH SHORTLY BEFORE SUNRISE ON MONDAY AS
THE UPPER LEVEL RIDGE AXIS SLOWLY DRIFTS EASTWARD THROUGH THE
MORNING HOURS. THE LOW LEVEL JET WILL RESULT IN SOME MOISTURE
ADVECTION FROM THE GREAT PLAINS WITH DEWPOINTS RETURNING TO THE
40S AND 50S ALONG AND EAST OF THE I-25 CORRIDOR. WITH THE RIDGE
AXIS NOT AS STRONG AS SUNDAY, THIS WILL ALLOW A WEAK SHORTWAVE
TO CLIP THE NORTHERN ZONES MONDAY AFTERNOON. EXPECT ISOLATED
SHOWERS AND THUNDERSTORMS TO DEVELOP ALONG AND AHEAD OF THIS
SHORTWAVE AS IT DIGS SLIGHTLY SOUTHEAST. KEPT POP AROUND 15 TO
30 PERCENT MONDAY AFTERNOON AND EVENING ALONG AND EAST OF THE
LARAMIE RANGE. LARAMIE VALLEY MAY GET SOME OF THIS ACTIVITY, BUT
SURFACE MOISTURE WON'T BE AS FAVORABLE IN THE AFTERNOON.
THUNDERSTORMS LOOK SUB-SEVERE AT THIS TIME WITH ONLY ABOUT 20 TO
25 KNOTS OF SHEAR AND MLCAPE BETWEEN 400 TO 1000 J/KG, HIGHEST
OVER THE SOUTHERN NEBRASKA PANHANDLE. GUSTY OUTFLOW WINDS APPEAR
TO BE THE MAIN THREAT FROM ANY THUNDERSTORM ACTIVITY. OTHERWISE,
HIGH TEMPERATURES WILL BE SIMILAR TO SUNDAY AND MAYBE EVEN A FEW
DEGREES WARMER WITH CHEYENNE AROUND 90 DEGREES FOR AN AFTERNOON
HIGH. LOW LEVEL JET WILL INTENSIFY AGAIN MONDAY NIGHT, BUT NOT
QUITE AS STRONG AS SUNDAY NIGHT/EARLY MONDAY.
LONG TERM /TUESDAY THROUGH SATURDAY/
ISSUED AT 1212 PM MDT SAT JUL 4 2026
THE LONG-TERM LOOKS TO BE DOMINATED BY A STUBBORN UPPER LEVEL RIDGE
THAT WILL POSITION ITSELF OVER THE FOUR CORNERS AREA. WE WILL BE ON
THE NORTHERN END OF THIS RIDGE WHICH MAY ALLOW A FEW SUBTLE
SHORTWAVES TO PASS NEARBY TO ADD SOME UNSETTLED WEATHER CHANCES.
OTHERWISE, EXPECT TYPICAL EARLY SUMMER TIME CONDITIONS TO BECOME
MORE PREVALENT THROUGH AT LEAST THE NEXT WEEK.
TUESDAY THROUGH THURSDAY WILL KEEP THE CONDITIONAL AFTERNOON
THUNDERSTORM TREND GOING. THE PLUME OF MONSOON MOISTURE WILL KEEP
PWATS ELEVATED OF 0.75 TO 1.5" ACROSS THE REGION. ENOUGH LOW LEVEL
CONVERGENCE WILL PROVIDE LIFT FOR THUNDERSTORMS. ADDITIONALLY, BULK
WIND SHEAR OF 35-45 KNOTS MAY BE ENOUGH TO SUPPORT MORE ORGANIZED
CONVECTION AND SOME SEVERE RISKS. MACHINE LEARNING MODELS ARE
HIGHLIGHTING LOW END CHANCES OF SEVERE WEATHER THROUGH THIS PERIOD
FROM THE GFS ENSEMBLE MODELS.
THURSDAY THROUGH SATURDAY WE WILL FOCUS ATTENTION AT ELEVATED FIRE
WEATHER CONCERNS. THE MOISTURE THAT HAD KEPT RELATIVE HUMIDITY
VALUES UP MAY HAVE ADVECTED EAST AND OUT OF THE AREA BY THIS TIME.
MINIMUM HUMIDITY VALUES MAY DROP INTO THE TEENS AND SINGLE DIGITS
FOR THE WESTERN COUNTIES THURSDAY AND SPREAD TO BE AREA WIDE FRIDAY
AND SATURDAY. HIGH TEMPERATURES START RISING AS WELL. SOME SPOTS MAY
GET CLOSE TO REACHING THE TRIPLE DIGITS FOR THE FIRST TIME THIS YEAR
DURING THIS PERIOD. WINDS SHOULD NOT BE VERY STRONG IN THIS RIDGING
REGIME WHICH WILL HELP KEEP MORE WIDESPREAD CRITICAL FIRE CONDITIONS
DOWN. FUELS ARE STARTING TO BECOME CRITICAL IN OUR WESTERN ZONES.
THE RAINS WE HAVE GOTTEN THE LAST FEW WEEKS HAVE INDUCED FLOODING IN
VERY LOCALIZED SPOTS AND AT LEAST AN INCH IN MANY PLACES, HOWEVER IT
WAS NOT ENOUGH TO OFFSET THE LACKLUSTER WINTER SEASON WE SAW. AS WE
GO INTO THE HOTTER AND DRIER PORTIONS OF SUMMER WE ANTICIPATE FUELS
TO CONTINUE TO CURE AND BECOME MORE SUSCEPTIBLE TO COMBUSTION AND
FIRE SPREAD. SINCE THIS IS FAIRLY FAR INTO THE FORECAST EXPECT
CHANGES TO DETAILS.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 540 AM MDT SUN JUL 5 2026
UPPER LEVEL RIDGE AXIS WILL BUILD NORTH AND STRENGTHEN OVER THE AREA
TODAY. MOSTLY SUNNY SKIES AND MINIMAL AVIATION IMPACTS ARE EXPECTED.
HAZARDS/WEATHER TRENDS: VFR CONDITIONS WILL PREVAIL OVER THE NEXT 24
HOURS. SOUTHEAST TO EASTERLY WINDS WILL BECOME GUSTY AFTER 22Z
TODAY, BUT MAINLY BETWEEN 02Z AND 10Z TONIGHT OVER THE EASTERN
PLAINS TERMINALS AND KLAR. CAN'T RULE OUT SOME GUSTS UP TO 35 KNOTS
NEAR KCDR AND KAIA.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...TJT
LONG TERM...RV
AVIATION...TJT
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page