686 FXUS63 KUNR 211715 AFDUNRArea Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 1115 AM MDT Sun Sep 21 2025
.KEY MESSAGES...
-Sunny and warm today
-Cool front will bring breezy winds and a few showers to the area Monday
-Dry with above normal temperatures mid-week on
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.DISCUSSION...(Today Through Saturday) Issued at 1256 AM MDT Sun Sep 21 2025
Upper ridge ahead of the Pac NW upper trough will support sunny and warm conds today. After this trough passes through the region, blocking ridge will build into the region, supporting dry and warm weather. Clear skies and light winds across the FA this morning. Moist easterly upslope flow may allow for a few areas of fog this morning on the SD Plains. Otherwise, sunny and dry weather can be expected today with highs in the 70s and 80s. Upper trough will dive SE into the central Rockies Monday, forcing a cold front into the region. Models have shifted the track of this system further SW, the result of which has decreased rain chances locally, with the best rain chances SW of the FA. Still expecting isolated showers across the area, mainly south of I90, with some thunder possible across scentral SD. Gusty northwest of 25 to 40 mph are likely on the SD Plains, breeziest east of the Black Hills. Rain chances shift south Monday night, with dry weather expected the rest of week. Upper ridge will build across the Northern Plains as a quasi-omega block develops, with dry weather and above normal temps looking likely across the region. Highs will generally be in the 70s and 80s with mostly clear skies.
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.AVIATION...(For the 18Z TAFS Through 18Z Monday) Issued At 1113 AM MDT Sun Sep 21 2025
A cold front will slide through the forecast area between 22/06Z and 22/12z. Northwest winds will increase behind this front. Otherwise VFR conds are expected through the valid forecast period.
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.UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. &&
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DISCUSSION/KEY MESSAGES...JC AVIATION...Hintz
NWS UNR Office Area Forecast Discussion