054 FXUS63 KUNR 080451 AFDUNRArea Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 1051 PM MDT Sun Sep 7 2025
.KEY MESSAGES...
- Mostly dry and hot conditions expected until mid-week.
- Precipitation chances increase towards the end of the week.
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.DISCUSSION...(This Evening Through Sunday) Issued at 135 PM MDT Sun Sep 7 2025
Current upper air models show upper ridge over the Rockies, with weak shortwave over western Wyoming and northwest flow over the forecast area this afternoon. Surface analysis shows high pressure now to our east, and a surface boundary running from central Montana into Wyoming. Satellite shows mid and high clouds invading from the west. Temperatures currently sit in the mid 70s to mid 80s this afternoon with breezy southeasterly winds.
Upper ridge broadens over the northern and central plains the rest of today through Monday, as upper low moves over the PAC NW. Deterministics also show the weak shortwave trekking across the forecast area during the day Monday. Limited moisture and energy has models a bit inconsistent as far as potential precipitation. CAMs do try to inject isolated showers Monday afternoon into the evening, however are inconsistent as to location. Have kept with the little to no PoP trend, and most places can expect to remain dry on Monday, however wont be surprised to see an isolated shower or two somewhere in western SD in the afternoon.
Upper ridge continues over the Rockies into the plains through Wednesday morning. Later Wednesday upper ridge axis slides east of the FA as the upper trough digs into the southwest CONUS, setting up southwest flow over the region. Shortwave energy ejecting up into the region the latter half of Wednesday will bring our next chance for showers/storms.
Upper flow gets a bit messy towards the end of the week, but deterministic models point towards the upper trough staying somewhere over the western CONUS, resulting in daily potential for precipitation through the weekend and possibly beyond.
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.AVIATION...(For the 06Z TAFS Through 06Z Monday Night) Issued At 1048 PM MDT Sun Sep 7 2025
VFR conditions are expected through the TAF period. Light and variable winds overnight will become gusty around 18 kts in the afternoon. There is a possibility of showers near KRAP tomorrow afternoon, however chances are too low to mention in the TAF at this time.
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.UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. &&
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DISCUSSION/KEY MESSAGES...Dye AVIATION...Pettett
NWS UNR Office Area Forecast Discussion