929
FXUS63 KUNR 010001
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
601 PM MDT FRI JUL 31 2026
KEY MESSAGES
- HOT THIS WEEKEND WITH HIGHS IN THE 90S AND LOWER 100S ON THE
PLAINS.
- ELEVATED TO NEAR CRITICAL FIRE WEATHER CONDITIONS THIS WEEKEND
INTO MONDAY.
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 00Z TAFS THROUGH 00Z SATURDAY EVENING)
ISSUED AT 601 PM MDT FRI JUL 31 2026
ISOLATED SHOWERS AND THUNDERSTORMS HAVE ENDED FOR THE EVENING,
WITH VFR CONDITIONS EXPECTED TONIGHT AND SATURDAY. BREEZY SOUTH
WINDS ARE EXPECTED OVERNIGHT AT KGCC, AND THEN ACROSS THE SOUTH
DAKOTA PLAINS INCLUDING KRAP STARTING MID-MORNING SATURDAY AND
CONTINUING THROUGH THE DAY INTO SATURDAY NIGHT. NO THUNDERSTORMS
ARE CURRENTLY EXPECTED SATURDAY.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION...JC
AVIATION...KSMITH
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