269
FXUS63 KUNR 090354
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
954 PM MDT WED JUL 8 2026
KEY MESSAGES
-UNSETTLED THROUGH THURSDAY AS A SERIES OF DISTURBANCES MOVE
THROUGH THE REGION
-SUFFICIENT MOISTURE AND SHEAR IS IN PLACE TO SUPPORT A FEW
STRONG TO SEVERE STORMS
-VERY HOT THIS WEEKEND INTO EARLY NEXT WEEK WITH RECORD HIGH
TEMPS POSSIBLE AND DANGEROUS HEAT
UPDATE
ISSUED AT 950 PM MDT WED JUL 8 2026
CONVECTION CONTINUES THIS EVENING ACROSS PORTIONS OF NORTHEASTERN
WYOMING, NORTHWESTERN SOUTH DAKOTA, AND SOUTHWESTERN SOUTH DAKOTA.
THE SEVERE THREAT HAS LARGELY ENDED.
NO MAJOR CHANGES TO THE FORECAST. MEAGER WESTERLY FLOW COUPLED
WITH WEAK LARGE-SCALE ASCENT WILL LIMIT OVERALL COVERAGE AND A
MORE WIDESPREAD SEVERE THREAT. EXPECT CONVECTION INITIATION ON
THE BLACK HILLS AFTER 1200-1300 THURSDAY AFTERNOON, WHERE MARGINAL
EFFECTIVE BULK SHEAR WILL BE IN PLACE (~25-30 KNOTS). A FEW
STRONG TO SEVERE STORMS ARE POSSIBLE; LARGE HAIL IS A THREAT WITH
ANY SUPERCELLULAR STRUCTURES THAT CAN SUSTAIN THEMSELVES. SIMILAR
TO THE PAST FEW DAYS, UP TO GOLF BALL SIZED HAIL ARE POSSIBLE
WITH THE STRONGEST TRANSIENT SINGLE CELLS.
BEYOND THE SEVERE THREAT TOMORROW, BUILDING HEAT WILL BECOME THE
DOMINANT WEATHER STORY ALONG WITH WORSENING FIRE WEATHER
CONDITIONS THROUGH THE WEEKEND INTO NEXT WEEK.
DISCUSSION
(THIS AFTERNOON THROUGH TUESDAY)
ISSUED AT 1103 AM MDT WED JUL 8 2026
IMPULSE FILLED WESTERLY FLOW REMAINS IN PLACE OVER THE FA. DAILY
CHANCES FOR THUNDERSTORMS CAN BE EXPECTED WITH STRONG TO SEVERE
STORMS POSSIBLE AT TIMES, THROUGH THURSDAY. WEAK IMPULSE WILL
ADVECT THROUGH THE SW THIRD THIS AFTERNOON AND SUPPORT TS
CLUSTERS. AMPLE LL MOISTURE IN PLACE COMBINED WITH SUFFICIENT DEEP
LAYER SHEAR WILL SUPPORT A FEW STRONG TO SEVERE STORMS, WITH
LARGE HAIL AND DAMAGING WIND THE MAIN THREATS, MAINLY INVOF OF THE
BLACK HILLS. GIVEN ML CAPE OF 1-2 KJ/KG, DEEP BULK LAYER SHEAR OF
35 TO 40 KNOTS EXPECT ISOLATED SUPERCELLS TO BE POSSIBLE, CAPABLE
OF PRODUCING LARGE HAIL AND DAMAGING WINDS. STORMS WILL CARRY SE
ACROSS THE SW FA THROUGH THE EVENING. MORE STORMS ARE EXPECTED
THUR AS SUFFICIENT LL MOISTURE WILL BE IN PLACE WITH WEAK
STABILITY AND ANOTHER IMPULSE. BEST CHANCES FOR STORMS WILL BE IN
THE AFTERNOON/EVENING. SIMILAR CAPE/SHEAR PARAMETERS WILL BE IN
PLACE TO AGAIN SUPPORT A FEW STRONG TO SEVERE STORMS, ESP OVER THE
SW THIRD. UPPER RIDGE BUILDS INTO THE REGION THIS WEEKEND, WITH
DRY AND HOT CONDS EXPECTED. HOT TEMPS AROUND 35C AT H85 WITH CLOSE
TO 6000M H5 HEIGHTS OVER WY, WILL OFFER RECORD TO NEAR RECORD
HIGHS WELL INTO THE 100S WITH SOME AREAS SEEING READINGS AROUND
110 ON PORTIONS OF THE PLAINS, ESP SUNDAY AND MONDAY. HOWEVER,
GIVEN HOW DRY THE BL WILL BE WITH DEWPOINTS FALLING INTO THE 20S
IN THE WEST TO THE 50S EAST, APPARENT T'S WILL ONLY TOP OUT IN THE
UPPER 90S TO LOWER 100S, HIGHEST ON THE SD PLAINS, SUPPORTING ADV
LEVEL NUMBERS. RIDGE BEGINS TO RETROGRADE THE MIDDLE OF NEXT
WEEK, WITH STORM CHANCES RETURNING AS THE ACTIVE NORTHERN
PERIPHERY OF THE RIDGE SETTLES BACK SOUTH.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z THURSDAY NIGHT)
ISSUED AT 954 PM MDT WED JUL 8 2026
THUNDERSTORMS WILL CONTINUE MOVE ACROSS PORTIONS OF WESTERN SOUTH
DAKOTA THROUGH THE OVERNIGHT HOURS. TRANSIENT MVFR CONDITIONS
ARE STILL POSSIBLE AROUND ANY HEAVIER PRECIPITATION CORES.
CONDITIONS WILL BEGIN TO IMPROVE BETWEEN 09/08-10Z AS STORMS
DIMINISH AND MOVE OUT OF THE REGION.
ANOTHER ROUND OF STORMS WILL BEGIN TO DEVELOP OVER NORTHEAST
WYOMING AND WESTERN SOUTH DAKOTA AROUND 09/18Z AND LASTING
THROUGH THE REMAINDER OF THE FORECAST PERIOD. HAIL, FREQUENT
LIGHTNING, AND GUSTY/ERRATIC WINDS CAN BE EXPECTED WITH ANY
STRONGER CONVECTIVE CORES. TRANSIENT MVFR/IFR CONDITIONS ALSO
EXPECTED AROUND ANY HEAVIER PRECIPITATION CORES.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
UPDATE...SE
DISCUSSION...JC
AVIATION...SCHULTZ
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