615 FXUS63 KUNR 052205 AFDUNRArea Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 405 PM MDT Fri Sep 5 2025
.KEY MESSAGES...
- A Frost Advisory has been issued. Please view hazard details at weather.gov/unr
- Warming trend will lead to temperatures climbing above seasonal normals for much of next week
- Expect dry conditions throughout the weekend
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.DISCUSSION...(This Evening Through Friday) Issued at 118 PM MDT Fri Sep 5 2025
A big upper level low continues to move east across the UP of Michigan this afternoon. In its wake cool and dry cyclonic flow persists across much of western SD and eastern Wyoming. Even with ample sunshine the CAA and stiff NW winds have kept temperatures on the cooler side with widespread 60s common across the region. Building heights are expected as the ridge continues to build across much of the Intermountain west and transition eastward. This will east the pressure gradient across the area and allow the breezy conditions to diminish during the evening hours. With drier air mixing in and allowing for mostly clear to clear skies, temperatures are progged to fall into the 30s this evening across a large portion of the region. The sheltered valleys and those typically cold spots could see temperatures approach freezing. Confidence is high across northwestern SD to see temperatures drop and last for several hours and this as prompted for a Frost Advisory to be issued for these areas. Lower elevations across the Black Hills and Rapid City eastward will hold on to some light, downsloping winds that will keep temperatures from turning too cold but minimum temperatures could still drop to around 38-40F this evening across these areas.
Ridging becomes the dominant weather feature by the latter part of the weekend and most of next week. Temperatures will rebound as multiple days under the ridge will lead to a moderating thermal ridge which will lead to temperatures warming back into the mid to upper 80s for several days next week with mostly dry conditions.
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.AVIATION...(For the 00Z TAFS Through 00Z Saturday Evening) Issued At 404 PM MDT Fri Sep 5 2025
VFR conditions are expected for the next 24 hours. Gusty northwest winds will decrease after sunset. Winds will be light and variable overnight.
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.UNR WATCHES/WARNINGS/ADVISORIES... SD...Frost Advisory from 2 AM to 7 AM MDT Saturday for SDZ001-002-012- 078. WY...Frost Advisory from 2 AM to 7 AM MDT Saturday for WYZ056-060. &&
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DISCUSSION/KEY MESSAGES...Woodward AVIATION...Wong
NWS UNR Office Area Forecast Discussion