477
FXUS63 KUNR 311957
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
157 PM MDT SUN MAY 31 2026
KEY MESSAGES
- UNSETTLED WEATHER PATTERN CONTINUES WITH DAILY CHANCES OF
SHOWERS AND THUNDERSTORMS TODAY THROUGHOUT THIS COMING WEEK.
- OVERALL SEVERE WEATHER RISK WILL REMAIN ISOLATED TODAY AND
MONDAY, BUT WILL INCREASE TUESDAY WITH DAMAGING WINDS AND LARGE
HAIL POSSIBLE.
DISCUSSION
(THIS EVENING THROUGH SUNDAY)
ISSUED AT 157 PM MDT SUN MAY 31 2026
AN AREA OF LOW PRESSURE JUST TO OUR WEST WILL SUPPORT ADDITIONAL
ROUNDS OF ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TODAY AND
MONDAY. TODAY, CELLS ARE ESPECIALLY FIRING OVER THE BLACK HILLS
CORRIDOR (ALTHOUGH A FEW CELLS HAVE BEEN NOTED IN NORTHEASTERN
WYOMING TOO) AND WILL PUSH EAST WITH TIME. TODAY'S ENVIRONMENT
FEATURES MODEST CAPE, BUT VERY LITTLE WIND SHEAR, SO THE SEVERE
WEATHER THREAT SEEMS VERY LIMITED/ISOLATED AND BRIEF IN DURATION
WITH A "PULSE" STORM MODE. IT IS WORTH NOTING THAT ANY STORMS THAT
CAN TRACK EAST OFF THE TERRAIN INTO THE SOUTH DAKOTA PLAINS WILL
HAVE ACCESS TO THE BEST INSTABILITY AND SFC MOISTURE PER
MESOANALYSIS AND SHORT-TERM MODEL PROJECTIONS, YET THE LACK OF SHEAR
WILL TEND TO LIMIT STORM ORGANIZATION AND LONGEVITY. MONDAY, WIND
SHEAR INCREASES, BUT INSTABILITY REMAINS MODEST, SO THE OVERALL
SEVERE THREAT REMAINS LOW/ISOLATED WITH PERHAPS GUSTY WINDS OR HAIL
ON A FEW OF THE STRONGER CELLS. NORTHEAST WYOMING, THE BLACK HILLS,
AND ADJACENT SOUTH DAKOTA PLAINS WILL AGAIN BE FAVORED FOR ISOLATED
TO SCATTERED ACTIVITY. HIGH TEMPERATURES BOTH DAYS WILL GENERALLY
TOP OUT IN THE 70S, WITH SOME 80S POSSIBLE ACROSS OUR SOUTHERN SOUTH
DAKOTA COUNTIES.
TUESDAY IS STARTING TO LOOK MORE CONCERNING, WITH A SIGNIFICANT
INCREASE IN BOTH DEEP-LAYER WIND SHEAR (AS HIGH AS 30-40KTS)
OVERLAPPING WITH HIGHER INSTABILITY (POSSIBLY 2,000 J/KG SBCAPE),
PUTTING US AT RISK FOR A MULTICELL TO SUPERCELL STORM MODE WITH
GREATER RISKS FOR DAMAGING WINDS AND LARGE HAIL...ALL AHEAD OF A
SHORTWAVE AND COLD FRONT. MOISTURE CONTINUES TO LOOK GOOD AS WELL.
THE NWS STORM PREDICTION CENTER HAS ISSUED A SLIGHT RISK (LEVEL 2 OF
5) FOR SEVERE THUNDERSTORMS ACROSS MOST OF OUR SOUTH DAKOTA
COUNTIES, AND A MARGINAL RISK (LEVEL 1 OF 5) ACROSS NORTHEASTERN
WYOMING. WE'LL DEFINITELY BE KEEPING AN EYE ON TUESDAY'S ENVIRONMENT
IN THE DAYS AHEAD. STORM INITIATION CURRENTLY LOOKS TO OCCUR
BETWEEN 1 PM AND 3 PM.
AN UNSETTLED PATTERN WITH DAILY CHANCES OF AT LEAST ISOLATED SHOWERS
AND THUNDERSTORMS WILL CONTINUE THROUGH THE END OF THE WEEK. HIGH
TEMPERATURES BY NEXT WEEKEND MAY MAKE A RUN BACK TOWARD THE 90S.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z MONDAY)
ISSUED AT 1116 AM MDT SUN MAY 31 2026
AREAS OF LOW VFR/MVFR CIGS ARE PRESENT ACROSS NORTHEAST WY AND
WILL PERSIST THROUGH THE REMAINDER OF THE AFTERNOON. VSBYS WILL
REMAIN VFR UNTIL SCT SHOWERS DEVELOP BY 21Z, THEN MAY FALL INTO
MVFR STATUS WITH SOME OF THE HEAVIER SHOWERS. VFR CONDITIONS ARE
PRESENT ACROSS MUCH OF WESTERN SD WITH TSRA DEVELOPING ACROSS THE
BLACK HILLS PRESENTLY. SCT TSRA ALSO PRESENT WEST OF KCUT IN
WYOMING. THUNDERSTORMS WILL BECOME MORE NUMEROUS THROUGH THE
AFTERNOON, WITH MVFR CIGS/VSBYS PRESENT WITH THE STRONGER STORMS.
THE STORMS ARE EXPECTED TO END BY 01/06Z ACROSS THE AREA WITH VFR
CONDITIONS PRESENT AFTERWORDS.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION/KEY MESSAGES...KSMITH
AVIATION...HINTZ
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