809
FXUS63 KUNR 302319
AFDUNR
AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY
NATIONAL WEATHER SERVICE RAPID CITY SD
519 PM MDT SUN AUG 30 2026
KEY MESSAGES
- ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON
AND EVENING FROM NORTHEAST WY, ACROSS THE BLACK HILLS, INTO THE
NORTHWESTERN SD. STRONG TO SEVERE STORMS COULD PRODUCE DAMAGING
WINDS OF 60-75 MPH, HAIL, AND FREQUENT LIGHTNING.
- VERY WARM WEATHER CONTINUES THROUGHOUT THE NEXT 7 DAYS.
- NEAR-CRITICAL FIRE WEATHER CONCERNS CONTINUE INTO EARLY NEXT
WEEK, MAINLY OVER NORTHEASTERN WY INTO SOUTHWESTERN SD.
DISCUSSION
(THIS AFTERNOON THROUGH SATURDAY)
ISSUED AT 1152 AM MDT SUN AUG 30 2026
UPPER AIR ANALYSIS DEPICTS UPPER SHORTWAVE OVER NORTHERN
ID/SOUTHERN SK. WATER VAPOR IMAGERY SHOWS LINE OF CONVECTION
DEVELOPING OVER CENTRAL MT/WY AND MOVING EASTWARD. THESE STORMS
WILL MOVE INTO THE CWA IN THE NEXT SEVERAL HOURS. INVERTED-V
SOUNDINGS INDICATE DAMAGING WIND GUSTS WILL BE THE MAIN CONCERNS
WITH THESE STORMS. SOME GUSTS OVER NW SD COULD EXCEED 75+ MPH.
RIGHT NOW, THERE'S SOME UNCERTAINTY AS TO HOW FAR SOUTH THESE
STORMS WILL EXTEND AND IF THEY'LL IMPACT THE RAPID CITY AREA.
BROAD UPPER LEVEL RIDGE BUILDS OVER THE CENTRAL/EASTERN HALF OF
THE US FOR THE BEGINNING OF THE WEEK. THIS WILL LEAD TO CONTINUING
WARM CONDITIONS OVER OUR CWA AND MOSTLY DRY CONDITIONS, THOUGH
AFTERNOON STORMS ARE POSSIBLE TOMORROW AND TUESDAY. DETERMINISTIC
MODELS SHOW THE RIDGE STRENGTHENING LATER IN THE WEEK, LEADING TO
MUCH WARMER CONDITIONS OVER WESTERN SD AND NORTHEASTERN WY WITH
HIGHS CLIMBING INTO THE MID TO UPPER 90S BY WEDNESDAY AND
THURSDAY. IN ADDITION TO THE HOT TEMPERATURES, THE VERY DRY
AIRMASS WILL LEAD TO ELEVATED TO NEAR-CRITICAL FIRE WEATHER
CONCERNS.
AVIATION
(FOR THE 00Z TAFS THROUGH 00Z MONDAY EVENING)
ISSUED AT 516 PM MDT SUN AUG 30 2026
AN IMPRESSIVE OUTFLOW BOUNDARY/COLD FRONT COMBINATION IS BLASTING
ACROSS WESTERN SD EARLY THIS EVENING WITH GUSTS AROUND 45KTS AND
BRIEF MVFR VSBYS DUE TO DUST. ISOLATED STRONG/SEVERE THUNDERSTORMS
WITH LOCAL IFR CONDITIONS WILL CONTINUE ALONG THE BOUNDARY NORTH
OF KPHP THROUGH 31/02Z. OTHERWISE, EXPECT VFR CONDITIONS THROUGH
THE PERIOD.
FIRE WEATHER
ISSUED AT 1152 AM MDT SUN AUG 30 2026
ISOLATED HIGH-BASED THUNDERSTORMS ARE POSSIBLE ACROSS
NORTHEASTERN WY THIS AFTERNOON AND EVENING. STORMS MAY PRODUCE
LIGHTNING AND GUSTY WINDS BUT NOT MUCH PRECIP. ELEVATED TO NEAR-
CRITICAL FIRE WEATHER CONDITIONS POSSIBLE OVER MUCH OF THE AREA
TOMORROW, ESPECIALLY OVER NORTHEASTERN WY WHERE HUMIDITIES MAY
DROP TO AS LOW AS 10%, HOWEVER WINDS ARE EXPECTED TO REMAIN LIGHT.
NEAR-CRITICAL FIRE WX CONDITIONS ARE POSSIBLE LATER THIS WEEK IN
THE WED/THU TIMEFRAME AS A HOT AND DRY AIRMASS MOVES INTO THE
REGION. AFTERNOON HUMIDITIES RANGING FROM 10 TO 20% AND BREEZY
SOUTHWEST WINDS WILL LEAD TO WIDESPREAD NEAR-CRITICAL FIRE WEATHER
CONCERNS ACROSS NORTHEASTERN WY INTO WESTERN SD.
UNR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
WY...NONE.
DISCUSSION...WONG
AVIATION...HELGESON
FIRE WEATHER...WONG
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