134
FXUS65 KCYS 020511
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1111 PM MDT SUN JUN 1 2025
KEY MESSAGES
- A PASSING WEATHER DISTURBANCE AND RELATIVELY STRONG COLD FRONT
FOR EARLY JUNE WILL MOVE ACROSS THE FORECAST AREA ON MONDAY,
PRODUCING WIDESPREAD SHOWERS AND SCATTERED THUNDERSTORMS
MONDAY AFTERNOON AND NIGHT. SOME OF THE THUNDERSTORMS SOUTH OF
A CHEYENNE TO CHADRON LINE MAY BECOME SEVERE MONDAY AFTERNOON
AND EVENING.
- COOLER AND WETTER WEATHER WILL PREVAIL FOR TUESDAY AND
WEDNESDAY BEFORE A WARMING TREND DEVELOPS FOR THURSDAY
THROUGH SATURDAY, WITH CHANCES FOR LATE DAY SHOWERS AND
THUNDERSTORMS EACH DAY.
SHORT TERM /THROUGH MONDAY NIGHT/
ISSUED AT 147 PM MDT SUN JUN 1 2025
TONIGHT...VISIBLE SATELLITE IMAGERY, WSR-88D REFLECTIVITY AND MODEL
GUIDANCE SUGGESTS ISOLATED TO WIDELY SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH EARLY THIS EVENING, MAINLY FOR SOUTHEAST
WYOMING. AS THE COLD FRONT APPROACHES OUR NORTHERN COUNTIES, WE MAY
SEE AN UPTICK IN SHOWER COVERAGE LATE THIS EVENING ACROSS CONVERSE
COUNTY. RELATIVELY QUIESCENT WEATHER AFTER MIDNIGHT IN ADVANCE OF
THE COLD FRONT.
MONDAY...QUITE AN ACTIVE DAY EXPECTED. AS THE PROGRESSIVE SHORTWAVE
TROUGH ALOFT MOVES INTO THE DAKOTAS, ITS ASSOCIATED COLD FRONT WILL
SWEEP SOUTHWARD ACROSS OUR COUNTIES, USHERING IN COOLER NORTH WINDS
AND WIDESPREAD LOW CLOUDS. WITH STRONG FRONTAL LIFTING AND A DEEP
MOIST AIRMASS, WE ANTICIPATE NUMEROUS SHOWERS AND THUNDERSTORMS TO
DEVELOP, ESPECIALLY IN THE AFTERNOON ALONG AND NEAR THE COLD FRONT.
WITH THE COMBINATION OF SHEAR AND INSTABILITY, SOME OF THE
THUNDERSTORMS WILL LIKELY BECOME SEVERE FROM LARAMIE COUNTY OF
SOUTHEAST WYOMING ACROSS THE SOUTHERN TWO-THIRDS OF THE NEBRASKA
PANHANDLE, WHERE THE STORM PREDICTION CENTER HAS THEIR SLIGHT RISK
AREA. MAXIMUM TEMPERATURES WILL BE TOUGH TO CALL BASED ON THE
STRENGTH OF THE COLD FRONT AND CLOUD COVER.
MONDAY NIGHT...AS THE COLD FRONTAL BAND IS OVERRIDDEN BY MOIST FLOW
ALOFT, NUMEROUS SHOWERS AND SCATTERED THUNDERSTORMS WILL CONTINUE
INTO THE EVENING HOURS, MOST NUMEROUS SOUTH OF A LARAMIE TO ALLIANCE
LINE. SOME OF THE STORMS MAY BE SEVERE EARLY IN THE EVENING IN THIS
CORRIDOR. SCATTERED TO POSSIBLY NUMEROUS SHOWERS WILL CONTINUE AFTER
MIDNIGHT IN THE MOIST AIRMASS, WITH CHILLY TEMPERATURES AS 700 MB
TEMPERATURES FALL TO -2 CELSIUS. THERE MAY BE SOME AREAS OF FOG
DEVELOPMENT IN AREAS WHERE RAIN DECREASES IN COVERAGE.
LONG TERM /TUESDAY THROUGH SUNDAY/
ISSUED AT 147 PM MDT SUN JUN 1 2025
MULTIPLE SHORTWAVES WILL GIVES US PRECIPITATION
CHANCES THROUGHOUT THE WORK WEEK MAINLY IN THE AFTERNOON AND
EVENING. HOWEVER, STARTING WEDNESDAY WE BEGIN TO HAVE OUR WESTERLY
DOWNSLOPE BECOME THE PREDOMINANT PATTERN ALLOWING TEMPERATURES TO
RISE FROM THE MID 60'S AND INTO THE 70'S THURSDAY WITH MORE
WIDESPREAD 70'S ON FRIDAY INTO THE WEEKEND.
TUESDAY, ANOTHER SHORTWAVE SWINGS THROUGH THE INTERMOUNTAIN WEST
FROM THE EARLY AFTERNOON AND INTO THE EVENING. THERE LOOKS TO BE A
VORT MAX ASSOCIATED WITH THIS SHORTWAVE THAT MAY BE THE PRIMARY
MEANS FOR LIFT. ON TOP OF THE VORT MAX THERE WILL BE A LITTLE BIT OF
SOME RESIDUAL MOISTURE FOR THE VORT MAX TO LIFT FOR SOME LIGHT
SHOWERS. GIVEN THE LACK OF REAL SYNOPTIC SUPPORT ANYTHING SEVERE IS
NOT LIKELY, HOWEVER SOME LIGHTNING AND THUNDER MAY BE POSSIBLE.
WEDNESDAY INTO THURSDAY, A MIDLEVEL TROUGH PUSHES THROUGH CONTINUING
THE RAIN CHANCES FOR THE INTERMOUNTAIN WEST. THERE SHOULD BE ENOUGH
SYNOPTIC LIFT AND WELL AS THE VORTICITY GRADIENT TO PRODUCE STRONGER
STORMS THAN TUESDAY. HOWEVER, MODEL GUIDANCE SHOWS DRY AIR FILLING
INTO THE REGION POTENTIALLY CUTTING OFF ANY CONVECTION INTO THE
OVERNIGHT HOURS OR EVENING IF THAT DRY AIR ARRIVES SOONER.
THURSDAY INTO FRIDAY, WESTERLY FLOW STARTS TO DOMINATE THE PATTERN
ALLOWING US TO GET A SMALL BREAK FROM THE PRECIPITATION CHANCES. DRY
AIR LOOKS TO START FILING INTO THE LOWER ELEVATIONS GIVING US A DRY
LAYER NEAR THE SURFACE THAT MAY POSSIBLY NOT ALLOW PRECIPITATION
FROM REACHING THE SURFACE.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 1107 PM MDT SUN JUN 1 2025
ISOLATED SHOWERS AND STORMS HAVE COME TO AN END ACROSS SOUTHEAST
WYOMING AND WESTERN NEBRASKA WITH A CALM NIGHT AND EARLY MORNING
EXPECTED. A BRIEF PERIOD OF PATCHY FOG IS POSSIBLE AROUND KCYS,
BUT CONFIDENCE IN THIS FOG DEVELOPING IS LOW. WINDS REMAINS
LIGHT AND VARIABLE OVERNIGHT INTO THE EARLY MORNING HOURS BEFORE
INCREASING WITH THE PASSING COLD FRONT LATER THIS AFTERNOON AND
EVENING. THIS COLD FRONT WILL INITIATE STRONG TO SEVERE STORMS
ACROSS THE REGION WITH ALL TERMINALS POTENTIALLY SEEING IMPACTS
FROM STORMS. GUSTY, ERRATIC WINDS AND LARGE HAIL WILL BE
POSSIBLE IN AND AROUND ALL STORMS THAT DEVELOP. STORMS WILL COME
TO AN END IN THE EVENING WITH LOW CEILINGS MOVING IN OVERNIGHT.
CYS WATCHES/WARNINGS/ADVISORIES
WY...NONE.
NE...NONE.
SHORT TERM...RUBIN
LONG TERM...MM
AVIATION...AM
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