FXUS63 KUNR 110501 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 1001 PM MST Wed Dec 10 2025 .KEY MESSAGES... -Mixed precip expected across the area tonight, with some icing across portions of NW SD -Warm Thurs ahead of an arctic front -Cold and snowy Thur night into Sat with some snow accums, heaviest across NW SD where a few inches are possible -Warm and dry next week && .DISCUSSION...(This Evening Through Wednesday) Issued at 128 PM MST Wed Dec 10 2025 Active northern stream will continue to bring wild swings in temps along with precip chances through the end of the week. Massive western CONUS ridge will support another CP front into the region tomorrow as a clipper system tops the ridge. This system is supporting strong WAA over the region today, with high centered upglide supporting a developing band of precip over the region this afternoon. Precip is fighting a very dry layer in the lower atmosphere, indicated by the 18Z UNR raob. However, this layer will eventually saturate with precip reaching the ground this evening on the Plains. Still expecting a good chance of icing across portions of NW SD, esp from Lemmon to Dupree where a tenth or so of ice is expected. Did trim back the adv in the far west given staunch WAA, which now supports a very narrow window of mixed precip across Harding and esp Butte Counties. Temps there should rise above freezing this evening and remain above freezing through the night. The other question mark will be Haakon County where precip chances look more limited with marginal profiles. Most places will see warm temps Thur ahead of the clipper with westerly flow supporting decent mixing. Expecting highs in the 50s and 60s across the southern half of the FA, warmest in SW SD. Coolest locations will be in NW SD. Cold front will settle into the region Thur afternoon/evening with temps falling through the night. Baroclinic zone will setup over the region and stall with several weak impulses agitating the flow and supporting rounds of light snow. Accums will range form 1 to 2 inches in the SW half to third with 2 to 4 inches across the NE half. Easterly upslope flow may allow for some enhancement in the BH foothills, esp given cold profiles supporting higher snow ratios. In addition, some upslope fog will also be possible Friday into Sat. Upper ridge begins to shift east Sunday with things warming back up next week, along with breezy conds as the nearby active northern stream supports traversing impulses, which could eventually bring another round of cold air toward the end of the week. && .AVIATION...(For the 06Z TAFS Through 06Z Thursday Night) Issued At 1000 PM MST Wed Dec 10 2025 A band of mixed precipitation continues to push eastward through the forecast area with MVFR/IFR conditions in heavier precipitation. Mainly VFR conditions expected for a short period Thursday morning/early afternoon, but then MVFR/IFR conditions due to snow will develop late in the period and affect the entire area after 12/00z. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...Winter Weather Advisory until 11 PM MST this evening for SDZ001. Winter Weather Advisory until 11 AM MST Thursday for SDZ002-013- 014-032-078. WY...None. && $$ DISCUSSION/KEY MESSAGES...JC AVIATION...SE