951 FXUS63 KUNR 270757 AFDUNRArea Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 157 AM MDT Sat Sep 27 2025
.KEY MESSAGES...
- Mostly dry with above average temperatures through Thursday - Gusty southerly winds at times through Monday - Elevated fire weather conditions at times
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.DISCUSSION...(Today Through Friday) Issued at 155 AM MDT Sat Sep 27 2025
07z surface analysis had weak high pressure over the CWA with little evidence of clouds overhead. Water vapour loop had upper trough shifting into the Great Lakes as upper ridge rebounds into the northern Rockies and upper low spins over southern CA.
Today through Monday, upper ridges moves through the northern plains and then Midwest as thermal ridge builds back into the area. Southwest flow aloft develops on backside of ridge by Monday. Lee surface trough strengthens with decent gradient ahead of it supporting gusty southerly winds, particularly over the western SD plains. Wind gusts will flirt with advisory criteria during peak mixing over northwest SD today and then east of the Black Hills for Sunday/Monday. Probability of gusts >45mph 90F 50-90% east of the Black Hills.
Tuesday/Wednesday, southwest flow aloft continues as upper trough becomes established over the northwest CONUS. This trough then moves into the northern Plains for the end of the week into next weekend, but timing may slowed by upper ridge over the eastern half of the CONUS. Trend will be cooler temperatures and increasing PoPs, but substantial QPF chances low.
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.AVIATION...(For the 06Z TAFS Through 06Z Saturday Night) Issued At 921 PM MDT Fri Sep 26 2025
VFR conds through the period. Gusty southerly winds can be expected Saturday.
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.FIRE WEATHER... Issued At 155 AM MDT Sat Sep 27 2025
Elevated fire danger continues through Monday as sustained dry and unseasonably warm weather continues. Gusty southerly winds will develop, especially over northwestern SD this afternoon and east of the Black Hills Sunday/Monday. MinRH in the 20s expected with some 30s over central South Dakota Monday. High to very high grassland fire danger expected through the period over portions of the western SD plains.
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.UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. &&
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DISCUSSION/KEY MESSAGES...Helgeson AVIATION...JC FIRE WEATHER...Helgeson
NWS UNR Office Area Forecast Discussion