036
FXUS63 KUNR 242324
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
524 PM MDT WED JUN 24 2026
KEY MESSAGES
- ISOLATED SEVERE THUNDERSTORMS POSSIBLE THIS AFTERNOON/EVENING
ACROSS PORTIONS OF NORTHEASTERN WY AND SOUTHWESTERN SD. MAIN HAZARDS
WILL BE LARGE HAIL (1+" IN DIAMETER) AND DAMAGING WIND GUSTS (60+
MPH)
- SLIGHT RISK OF SEVERE THUNDERSTORMS THURSDAY AFTERNOON/EVENING,
MAINLY ACROSS NORTHEASTERN WY
- ACTIVE PATTERN CONTINUES WITH CHANCES FOR SEVERE STORMS FRIDAY AND
SATURDAY, THOUGH THERE IS STILL SOME UNCERTAINTY IN LOCATION AND
TIMING.
DISCUSSION
(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1149 AM MDT WED JUN 24 2026
UPPER AIR ANALYSIS DEPICTS WEAK WAVE MOVING ACROSS NORTHEASTERN
WY INTO WESTERN SD. THE DISTURBANCE HAS TRIGGERED THE DEVELOPMENT
OF A FEW SHOWERS/STORMS OVER NORTHEASTERN WY AND THE BLACK HILLS.
THIS ACTIVITY SHOULD CONTINUE THROUGH THE AFTERNOON AND EVENING
HOURS AS 500 MB SPEED MAX REMAINS OVER THE REGION. BULK SHEAR
VALUES OF 40-50KT AND MODEST INSTABILITY OF 500-1000 J/KG SHOULD
CONTRIBUTE TO A MARGINAL SEVERE THREAT ACROSS PORTIONS OF
NORTHEASTERN WY INTO SOUTHWESTERN SD WITH THE MAIN HAZARDS BEING
LARGE HAIL AND DAMAGING WINDS.
NEAR ZONAL FLOW PATTERN CONTINUES THROUGH THURSDAY WITH ANOTHER
SHORTWAVE MOVING ACROSS THE NORTHERN PLAINS BY THE
AFTERNOON/EVENING HOURS. MORNING CLOUD COVER MAY LIMIT DAYTIME
HEATING AND OVERALL SEVERE POTENTIAL WITH 12Z MODELS SHOWING
~500-1500 J/KG CAPE OVER THE FAR WESTERN REACHES OF OUR CWA BY 3
PM TOMORROW AFTERNOON. MOST RECENT CAMS INDICATE A LINE OF STORMS
DEVELOPING OFF THE BIG HORNS TOMORROW AFTERNOON WITH INITIAL STORM
DEVELOPMENT HAVING THE GREATEST SEVERE POTENTIAL (MAIN HAZARDS
WILL BE LARGE HAIL AND DAMAGING WINDS). THE LINE OF STORMS WILL
MOVE EASTWARD THROUGH THE CWA AS THE EVENING PROGRESSES. WHILE A
FEW STORMS MAY BECOME STRONG AND WE COULD SEE SOME SEVERE CALIBER
WIND GUSTS AS THE LINE MOVES THROUGH, AS OF NOW NOT ANTICIPATING
ANY WIDESPREAD SEVERE WEATHER ACROSS WESTERN SD AS THE STORMS MOVE
THROUGH.
LONGWAVE TROUGH MOVES INTO THE WESTERN US ON FRIDAY WITH ZONAL
WESTERLY FLOW OVER OUR NECK OF THE WOODS TRANSITIONING TO
SOUTHWEST FLOW. SOUTHEASTERLY SFC FLOW WILL BRING WARM, MOIST AIR
INTO THE REGION WITH ML CAPE VALUES RISING TO 2000 TO 3000 J/KG
ACROSS WESTERN SD BY THE LATE AFTERNOON/EVENING HOURS. HOWEVER
WEAK UPPER LEVEL RIDGING AND WARM 750 MB TEMPS CONTRIBUTING TO A
STRONG CAP WILL LIKELY KEEP THE SEVERE THREAT CONDITIONAL FOR
FRIDAY.
ATTENTION TURNS TO SEVERE POTENTIAL ON SATURDAY AS A SHORTWAVE
AND ATTENDANT LEE CYCLONE MOVES THROUGH THE REGION. THERE'S STILL
SOME UNCERTAINTY AS TO THE TIMING AND LOCATION OF THE LEE CYCLONE
AND WHERE THE GREATEST INSTABILITY WILL BE BY THE AFTERNOON. SO
CORRESPONDINGLY, CONFIDENCE IS LOW IN THE EXACT LOCATION AND
TIMING OF ANY SEVERE WEATHER RISKS FOR SATURDAY WITH THE MOST
LIKELY AREA TO SEE SEVERE WEATHER ACROSS PORTIONS OF NORTHWESTERN
AND NORTH CENTRAL SD.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z THURSDAY EVENING)
ISSUED AT 521 PM MDT WED JUN 24 2026
LOW VFR (040-100) CIGS ARE EXPECTED FOR MUCH OF THE TAF PERIOD FOR
THE SOUTHERN HALF OF OUR FORECAST AREA. THE TAF SITES ARE NOT
EXPECTED TO GO BELOW VFR. FAR SOUTHWESTERN SD INTO THE SOUTHERN
BLACK HILLS COULD SEE MVFR/IFR CIGS THURSDAY MORNING INTO THE
AFTERNOON. SHOWERS/STORMS ARE ONGOING EAST OF THE BLACK HILLS INTO
SOUTH CENTRAL SD AND WILL CONTINUE TO MOVE EAST THIS EVENING. MORE
SHOWER/STORMS MOVE IN TONIGHT INTO THURSDAY MORNING, AFFECTING
MAINLY SOUTHWESTERN SD AND NORTHEAST WYOMING. LOW CONFIDENCE THAT
THEY WILL AFFECT THE TAF SITES.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION...WONG
AVIATION...DYE
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page