922 FXUS63 KUNR 111922 AFDUNRArea Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 122 PM MDT Thu Sep 11 2025
.KEY MESSAGES...
-Seasonally warm through Friday
-Isolated showers and thunderstorms through Friday with better coverage of showers this weekend most places
-Cooler after Monday next week
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.DISCUSSION...(This Evening Through Thursday) Issued at 121 PM MDT Thu Sep 11 2025
Mean western CONUS trough continues to support semi-unsettled weather across much of the Northern Plains and Rockies. This system will continue to slowly shift east the next two days, with better forcing shifting east by this weekend. This will support increasingly unsettled weather in the Northern Plains. Weak impulses will continue to shift northeast into the region ahead the upper trough and support daily isolated shower/TS chances through Friday. Gusty winds will be the main impact from any stronger cells given plenty of low level dry air in place off the sfc. Upper trough will shift east by this weekend with the main batch of LSA and forcing spreading over the region. The the best overlap of forcing and moisture will be well north of the FA. However, the NAM and Canadian support higher precip totals over the FA, likely due to convective contamination. However, most other models generally keep the higher precip numbers north and east of most of the area, which makes the most sense given the best progged overlap of moisture and lift. Hence, will keep the higher pops toward NW SD, with any rain over the southern 2/3 of the FA expected to be convective and scattered. Cooler weather can be expected this weekend with all the moisture and clouds around, but there is really is not much of any CAA with this system. Things dry out for the first part of next week, with warmer temps Monday, but another upper trough moves into the region later in the week, supporting additional rain chances as well as a cooler temps. However, confidence in the track, strength, and resultant precip chances remain very low attm given progged semi-blocked flow, which typically leads to high forecast model uncertainty.
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.AVIATION...(For the 18Z TAFS Through 18Z Friday) Issued At 1147 AM MDT Thu Sep 11 2025
Mainly VFR conditions are expected today into tonight. Isolated to scattered thunderstorms will be possible across most of the area this afternoon into tonight, with brief MVFR conditions in the vicinity of stronger storms. Best chances for storms in and around KRAP and KGCC will be from 22Z through 03Z.
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.UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. &&
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DISCUSSION/KEY MESSAGES...JC AVIATION...Dye
NWS UNR Office Area Forecast Discussion