245
FXUS63 KUNR 011134
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
534 AM MDT SAT AUG 1 2026
KEY MESSAGES
- DRY CONDITIONS THIS WEEKEND WITH NO THUNDERSTORMS EXPECTED.
- VERY HOT THIS WEEKEND WITH HIGHS IN THE 90S AND LOWER 100S ON
THE PLAINS, BEFORE A BRIEF RELATIVE COOL-DOWN EARLY NEXT WEEK.
- ELEVATED TO NEAR-CRITICAL FIRE WEATHER CONDITIONS THIS WEEKEND
INTO MONDAY.
UPDATE
ISSUED AT 1051 PM MDT FRI JUL 31 2026
NO MAJOR CHANGES WERE NEEDED WITH THIS EVENING'S FORECAST UPDATE.
GREAT CONSENSUS AMONG THE CAMS IN NO ISOLATED THUNDERSTORM RISK
THIS WEEKEND. SUNDAY STILL LOOKS LIKE THE HOTTEST DAY AND BEST
CANDIDATE FOR AT LEAST A FEW OF OUR SOUTH DAKOTA PLAINS ZONES TO
NEED HEAT ADVISORIES, BUT STILL SOMEWHAT MARGINAL AND WILL
CONTINUE TO HOLD OFF ON ANY ISSUANCES THIS EARLY. SPEAKING OF
TEMPERATURES...HAVE YOU SEEN TUESDAY'S FORECAST?! IT'S ONLY FOR
ONE DAY, BUT HIGHS HOLDING IN THE UPPER 60S OVER THE BLACK HILLS
TO THE UPPER 70S ACROSS NORTHEAST WYOMING AND OUR SOUTH DAKOTA
PLAINS!
DISCUSSION
(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 1121 AM MDT FRI JUL 31 2026
WESTERN CONUS UPPER RIDGE WILL SHIFT EAST INTO THE NORTHERN
PLAINS AND SUPPORT HOT AND DRY WEATHER AS A STRONGER UPPER TROUGH
MOVES INTO THE PAC NW. WEAK SHORTWAVE ADVECTING INTO THE FA TODAY
AND WILL MERGE WITH THE DEEPER TROUGH OVER THE UPPER MIDWEST.
LINGERING MOISTURE AND WEAK CIN WILL ALLOW A FEW SHOWERS AND
ISOLATED TS TO DEVELOP ACROSS THE WESTERN THIRD THIS AFTERNOON,
SPECIFICALLY NORTHEAST WY, THE SOUTHERN BH, AND MAYBE FAR NW SD.
LACK OF APPRECIABLE CAPE AND INSUFFICIENT DEEP LAYER SHEAR WILL
SUPPORT WEAK PULSE CONVECTION. HENCE, SEVERE WEATHER IS NOT
EXPECTED OTHER THAN GUSTY WINDS. CONVECTION WILL QUICKLY WANE THIS
EVENING. THERMAL RIDGE WILL SLOWLY SHIFT EAST AHEAD OF THE
ADVANCING NW PAC UPPER TROUGH, SUPPORTING HOT CONDS SAT AND SUN.
THE WARMEST DAY WILL BE SUNDAY WHEN HIGHS WILL REACH THE LOWER
100S AT MANY LOCATIONS ON THE PLAINS. A HEAT ADV MAY BE NEEDED ON
PORTIONS OF THE SD PLAINS SUNDAY AS HEAT INDEX READINGS WILL
REACH 100-105 IN SOME AREAS. LEE-SIDE TROUGH WILL SETTLE INTO THE
FA SUNDAY. HOWEVER, COOLER AIR WON'T ADVECT INTO THE FA UNTIL
MONDAY WHEN HIGHS WILL BE IN THE 80S AND LOW 90S, COOLEST NW.
STRONGER COLD FRONT WILL ARRIVE MONDAY NIGHT, WHICH WILL REALLY
KNOCK TEMPS DOWN FOR TUE. THIS SYSTEM MAY ALSO SUPPORT SOME
CONVECTION MONDAY NIGHT AS THE ENTRANCE REGION OF THE UPPER JET
WILL PUSH THROUGH THE REGION COUPLED WITH DEEP LAYER ASCENT AND
SUFFICIENT MOISTURE. HIGHS WILL MAINLY BE IN THE 70S TUE, THE
FIRST BELOW NORMAL DAY IN LONG WHILE. WESTERN RIDGE WILL FLATTEN
AS A DEEP UPPER LOW SLOWLY PUSHES EAST ACROSS INTERIOR CANADA.
THIS WILL SUPPORT A SLOW WARM UP AS SE RETURN FLOW ENSUES.
INCREASING LL MOISTURE WILL SUPPORT ISOLATED TS CHANCES BY WED AS
WEAK IMPULSES ADVECT THROUGH THE REGION IN NW FLOW.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 534 AM MDT SAT AUG 1 2026
VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD.
UNR WATCHES/WARNINGS/ADVISORIES
SD...HEAT ADVISORY FROM 10 AM TO 8 PM MDT SUNDAY FOR SDZ013-014-026-
027-030>032-041>044-072>077.
WY...NONE.
UPDATE...KSMITH
DISCUSSION...JC
AVIATION...13
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