492
FXUS63 KUNR 071145
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
545 AM MDT TUE JUL 7 2026
KEY MESSAGES
- ACTIVE THROUGH MID WEEK AS A SERIES OF DISTURBANCES MOVE
THROUGH THE REGION, WITH SEVERE THUNDERSTORMS POSSIBLE.
- VERY HOT THIS WEEKEND WITH RECORD HIGH TEMPS POSSIBLE AND
DANGEROUS HEAT SATURDAY AND SUNDAY.
UPDATE
ISSUED AT 1010 PM MDT MON JUL 6 2026
FORECAST REMAINS MOSTLY ON TRACK THIS EVENING. MAIN CONCERN FOR
THE OVERNIGHT HOURS WILL BE ELEVATED CONVECTION. CURRENTLY THE
SURFACE BOUNDARY RUNS FROM NORTHEASTERN SD, DOWN INTO SOUTHWESTERN
SD, AND CENTRAL WY. A MID- LEVEL IMPULSE IS SUPPORTING ELEVATED
CONVECTION BEHIND THE BOUNDARY IN NORTHEASTERN WY DOWN INTO FALL
RIVER COUNTY. SHEAR IS TOO WEAK TO SEE MUCH IN THE WAY OF
ORGANIZED CONVECTION, HOWEVER STORMS WILL BE CAPABLE OF STRONG
WIND GUSTS AS THEY TRAVERSE NORTHEAST IN THE OVERNIGHT HOURS.
ATTENTION THEN TURNS TO THE SEVERE STORM POTENTIAL FOR TUESDAY, AS
THE BOUNDARY LIES MOSTLY STATIONARY OVER THE FORECAST AREA.
STORMS EXPECTED TO DEVELOP IN THE AFTERNOON. BEST SHEAR LIES IN
THE NORTHERN HALF OF THE FA TUESDAY AFTERNOON, WITH 0-6KM SHOWING
BETWEEN 40-50 KTS. COUPLED WITH CAPE VALUES IN THE 1000-2000 J/KG
RANGE, WILL SUPPORT POTENTIAL FOR ISOLATED TO SCATTERED SEVERE
STORMS IN THE AFTERNOON AND EVENING.
DISCUSSION
(THIS AFTERNOON THROUGH SUNDAY)
ISSUED AT 1118 AM MDT MON JUL 6 2026
IMPULSE FILLED WESTERLY FLOW WILL BE IN PLACE OVER THE REGION
THROUGH MID WEEK AS A FRONTAL BOUNDARY STALLS OVER THE REGION.
NEAR DAILY CHANCES FOR THUNDERSTORMS CAN BE EXPECTED WITH SEVERE
STORMS POSSIBLE AT TIMES. TUES LOOKS TO BE THE BEST CHANCE FOR
SEVERE STORMS AS APPRECIABLE CAPE AND MODERATE BULK DEEP LAYER
SHEAR WILL BE IN PLACE. FRONTAL BOUNDARY HAS SHIFTED SOUTH THROUGH
MOST THE FA THIS MORNING AND WILL HANG UP IN SCENTRAL SD. SFC
BASED TS WILL BE POSSIBLE ALONG THE FRONT THIS AFTERNOON AS
DIURNAL HEATING ALLOWS THE CAP TO BE OVERCOME. FURTHER WEST,
ISOLATED TS WILL BE POSSIBLE OVER THE CENTRAL AND SOUTHERN BH
WHERE EDDY CONVERGENCE WILL BE IN PLACE WITH INCREASING MOISTURE
BEHIND THE FRONT. CONVECTION WILL WANE ACROSS THESE AREAS INTO THE
EVENING. HOWEVER, AN UPPER LEVEL IMPULSE WILL SUPPORT POS THETA-E
ADV ACROSS NORTHEAST WY OVERNIGHT, WITH A COMPLEX OF STORMS
POSSIBLE, AS HINTED AT IN HIRES MODELS. STORMS WILL CARRY ACROSS
NW SD OVERNIGHT INTO TUE MORNING. SFC FRONT WILL BE STALLED ACROSS
THE FA TUE, THE LOCATION OF WHICH WILL BE DICTATED BY OUTFLOW
FROM STORMS TO THE NORTH. MODERATELY STRONG IMPULSE WILL KICK OUT
OF WY/MT IN THE THE AFTERNOON AND EVENING AND WILL DRIVE CI THERE.
STORMS MAY ALSO FIRE ALONG THE FRONT IF CAPPING CAN BE OVERCOME,
THE STRENGTH OF WHICH VARIES IN FORECAST MODELS (CAPPING THAT IS).
GIVEN PROGGED ML CAPE OF 1-2 KJ/KG, DEEP BULK LAYER SHEAR OF 40
TO 50 KNOTS, EXPECT SUPERCELLS TO BE POSSIBLE WITH STRONG ROTATING
UPDRAFTS, CAPABLE OF PRODUCING LARGE HAIL AND DAMAGING WINDS. IN
ADDITION, GIVEN ESE FLOW INVOF OF THE SFC FRONT, THERE WILL BE A
SMALL CHANCE FOR TORNADOES. STORMS WILL CARRY ACROSS THE REGION
THROUGH THE EVENING. MORE STORMS ARE POSSIBLE WED AND THUR AS
SUFFICIENT LL MOISTURE WILL BE IN PLACE WITH WEAK STABILITY AND
ADDITIONAL IMPULSES. UPPER RIDGE BUILDS INTO THE REGION THIS
WEEKEND, WITH DRY AND HOT CONDS EXPECTED. IMPRESSIVE TEMPS OF 35
TO ALMOST 40C AT H85 WITH CLOSE TO 6000 H5 HEIGHTS OVER WY, WILL
OFFER RECORD TO NEAR RECORD HIGHS WELL INTO THE 100S WITH 110 TO
115 POSSIBLE ON PORTIONS OF THE PLAINS, ESP SUNDAY.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 545 AM MDT TUE JUL 7 2026
MVFR CIGS ARE IN PLACE OVER KRAP AND THE PLAINS SURROUNDING THE
BLACK HILLS FOR A FEW HOURS THIS MORNING. MANY SOURCES OF GUIDANCE
ARE NOT MODELING THIS WELL AND CONFIDENCE IS LOW ON EXACTLY HOW
QUICKLY IT WILL BURN OFF, BUT CURRENT THINKING IS AROUND 15Z/9AM
WITH DIURNAL HEATING. ATTENTION THEN TURNS TO THE POTENTIAL FOR
STRONG TO SEVERE THUNDERSTORMS TO DEVELOP ACROSS THE REGION
STARTING AS EARLY AS 21Z/3PM. ONGOING TEMPO FOR KRAP AND PROB30
FOR KGCC LOOK GOOD, BUT TWEAKED LOCAL TIMING BASED ON THE LATEST
CAMS AND ALSO INCREASED WIND POTENTIAL WITH THUNDERSTORMS AS THE
HREF ENSEMBLE WIND GUST MAX AND FORECAST SOUNDINGS ARE SHOWING
NUMEROUS CORES AND OUTFLOWS POTENTIALLY EXCEEDING 40-45KTS. STORMS
THIS AFTERNOON AND EVENING COULD PRODUCE LARGE HAIL, DAMAGING
WINDS, AND EVEN A TORNADO OR TWO. BIG PICTURE, THE STRONGEST AND
MOST WIDESPREAD ACTIVITY IS EXPECTED THROUGH 04-05Z/10-11PM, WITH
A STRAY STORM OR SHOWERS POTENTIALLY LINGERING A BIT LATER INTO
THE NIGHT. EXPECT SUDDEN DROPS TO AT LEAST MVFR CIGS/VSBYS NEAR
AND UNDER THUNDERSTORM CORES. CONDITIONS TREND QUIETER AND VFR
OVERNIGHT TONIGHT, BUT SOME LOWER CLOUDS MAY TRY TO BUILD ACROSS
THE SOUTH DAKOTA PLANS WESTWARD TOWARD KRAP NEAR OR JUST BEYOND
THE END OF THE CURRENT TAF PERIOD WEDNESDAY MORNING.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
UPDATE...DYE
DISCUSSION...JC
AVIATION...KSMITH
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