610 FXUS63 KUNR 181125 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 425 AM MST Tue Feb 18 2020 .DISCUSSION...(Today Through Monday) Issued at 252 AM MST Tue Feb 18 2020 Current surface analysis shows nearly stationary frontal boundary from eastern MT to northwest and central SD. Upper level analysis shows northwest flow across the region, with main shortwave energy upstream from the northern Rockies into the Canadian Rockies. Upper level jet wraps around from the Pacific NW into the central Rockies and Plains. KUDX radar starting to show a few snow showers over far northwest SD, with regional radars showing bulk of snow showers from central MT to western ND, moving southeastward. Temps are mostly in the teens and lower 20s with light winds. Shortwave energy will move southeast into the region today and tonight, helping to push the front southward through the area. Snow showers will increase in coverage from northwest to southeast, with the best chances generally from northeast WY to northwest SD, and eventually the Black Hills by midday as instability increases. Accumulations will mostly be light and scattered, but local amounts of 1 to 3 inches are certainly possible, especially over the Black Hills. Highs will mostly be in the morning or midday, teens north to around 30 far south, with temps steady or slowly falling in the afternoon as the front sags southward and northerly winds become breezy on the SD plains. Snow showers should dissipate in the evening, with variably cloudy skies and chilly temps overnight. Lows drop to the single digits to around zero in most areas with winds becoming light. Wednesday will be cold, but should see some sunshine, especially in the afternoon. Highs will be in the mid teens to mid 20s. Secondary shortwave moving southeast through the region could bring a little light snow to far southern SD, but better chances will be farther south across Nebraska. A few snow showers are also possible over the Black Hills area in the afternoon. Wednesday night will be cold again, with lows in the single digits, but warm air advection will take place late Wednesday night and especially on Thursday, with temps rebounding to near average levels in many areas on Thursday. The rest of the week and the weekend look to be dry and mild as large ridge over the western US moves east and flattens out over the Plains. Highs Friday through Sunday will mostly be in the 40s and 50s, though parts of northeast WY and areas with heavier snowpack may stay in the 30s. Unsettled and colder weather will return next week as one system likely slides south of the region late in the weekend and another pushes through the Rockies and into the Plains early next week. A lot of uncertainty on how the second system evolves as it moves into the region, but colder air will accompany it, along with increasing chances for snow. && .AVIATION...(For the 12Z TAFS Through 12Z Wednesday Morning) Issued At 421 AM MST Tue Feb 18 2020 A cold front will move from north to south across the region today followed by areas of MVFR/LCL IFR CIGS along with areas of MVFR VSBYS in snow showers. Expect local IFR conditions over and near the Black Hills this afternoon/evening. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION...26 AVIATION...10