171
FXUS63 KUNR 250809
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
209 AM MDT WED JUN 25 2025
KEY MESSAGES
- TSRA CHANCES CONTINUE TODAY, LOWER THURSDAY THROUGH SATURDAY,
THEN PICK BACK UP AGAIN SUNDAY INTO EARLY NEXT WEEK
- SUFFICIENT BUOYANCY/SHEAR FOR STRONG/SEVERE STORMS THROUGH THE
PERIOD, BUT LOW CONFIDENCE IN DETAILS
- WARMEST TEMPERATURES FRIDAY/SATURDAY
DISCUSSION
(TODAY THROUGH TUESDAY)
ISSUED AT 206 AM MDT WED JUN 25 2025
07Z SURFACE ANALYSIS HAD LOW OVER SOUTHEAST WY WITH SEVERAL
BOUNDARIES EXTENDING FROM IT INTO EASTERN MT AND SOUTHERN SD.
WATER VAPOUR LOOP HAD RIGHT ENTRANCE REGION OF 130KT JET STEAK
OVER THE CWA WHICH WAS ASSISTING A COUPLE CLUSTERS OF TSRA EARLY
THIS MORNING IN AN ENVIRONMENT CHARACTERIZED BY 0.5-1KJ/KG
MUCAPE/25-35KT EFFECTIVE BULK SHEAR. A COUPLE OF STRONGER STORMS
HAVE BEEN NOTED OVER THE PAST FEW HOURS. MAIN CONCERN THIS
FORECAST IS CONVECTION CHANCES.
TODAY/TONIGHT, UPPER TROUGH OVER UT/NV MOVES NORTHEAST AS IT
WEAKENS AND IS ABSORBED INTO WEST/SOUTHWEST FLOW ALOFT. EARLY
MORNING ELEVATED TSRA SHOULD WANE AND THEN PICK BACK UP AGAIN
DURING PEAK SOLAR INSOLATION THIS AFTERNOON. 0.5-1.5KJ/KG CAPE
WILL BE AVAILABLE WITH SUFFICIENT SHEAR FOR STRONG/ISOLATED SEVERE
THUNDERSTORMS. HOWEVER, ENOUGH SBCIN SHOULD BE AROUND TO SUPPRESS
ORGANIZED CONVECTION ESPECIALLY WITH LOW CLOUDS TO START THE DAY
FOR SOME AREAS. TEMPERATURES WILL BE NEAR GUIDANCE.
THURSDAY, THERMAL RIDGE EXPANDS INTO THE CWA WITH DECREASING
CAPE/SHEAR WHICH SHOULD LIMIT TSRA CHANCES, EXCEPT IN/NEAR THE
BLACK HILLS WHERE TERRAIN INFLUENCES WILL OCCUR. FRIDAY WILL BE
THE WARMEST DAY OF THE WEEK WITH TEMPERATURES WELL INTO THE 90S ON
THE SD PLAINS. A SURFACE TROUGH WILL MOVE THROUGH DURING PEAK
HEATING, WHICH MAY TRIGGER STRONG/SEVERE THUNDERSTORMS EAST OF THE
BLACK HILLS. WARM DAY SATURDAY WILL BECOME SLIGHTLY COOLER FOR
SUNDAY INTO EARLY NEXT WEEK AS NORTHWEST FLOW SETS UP PER UPPER
RIDGE BUILDING OVER THE ROCKIES. THIS RIDGE WILL EVENTUALLY PUSH
BACK INTO THE PLAINS.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING)
ISSUED AT 1030 PM MDT TUE JUN 24 2025
EASTERLY UPSLOPE FLOW WILL CONTINUE TO PROMOTE IFR/MVFR CIGS OVER
MUCH OF THE AREA LATER TONIGHT AS THE BL COOLS, WITH PATCHY FOG AS
WELL. STORMS WILL BE POSSIBLE LATE OVER THE NORTHWEST THIRD, WITH
ISOLATED ACTIVITY ELSEWHERE. IFR CONDS ARE CERTAINLY POSSIBLE
AROUND KRAP WED MORNING WITH UPSLOPE FLOW AND A SATURATED BL IN
PLACE. BETTER CHANCE FOR STORMS WED, ESP FROM THE BH EAST WHERE
COVERAGE WILL BE THE HIGHEST. EXPECT CONDS TO TREND VFR BY
AFTERNOON ALL PLACES.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...HELGESON
AVIATION...JC
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page