000 FXUS63 KUNR 041939 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 139 PM MDT Wed Oct 4 2023 .DISCUSSION...(This Evening Through Wednesday) Issued at 139 PM MDT Wed Oct 4 2023 Unsettled NW flow will continue over the region through the end of the work week. Steep low level lapse rates ahead of the approaching shortwave will support isold showers this afternoon, with most places not seeing much more than sprinkles where showers do materialize. Fast moving shortwave trough will push through the region tonight supporting chances for sct rain showers. Breezy NW winds will also develop as this system moves through. Showers will end most places by sunrise, with perhaps a few lingering showers over NW WY. Main impact from this wave will be gusty NW winds Thur afternoon. Wind speeds may reach low end adv levels for a period of time. However, given the downtrend in spreads from recent model runs and late arrival of faster winds, will let the night shift decide if an adv is needed for NW SD. In addition, steep ll lapse rates may support isold showers in the afternoon over much of the area, but given very dry profiles, will hold off on adding pops. Another fast moving clipper type system will push through the region Thu night, supporting another round of showers, possibly mixed with snow in the higher elevations of the Black Hills. This wave looks pretty dry attm, however, if a wetter solution, materializes, some light accums cannot be ruled out, esp above 6 kft. Temps will drop into the low to mid 30s most places Thur night with a few places dropping below freezing where skies clear and winds drop off. However, with the gusty winds and clouds, many locations may dodge a hard freeze or frost. Breezy and cool conds expected Friday. Sfc ridge will shift SE of the region Friday night with light winds, clear skies, and dry air allowing for strong radiational cooling. This will allow most locations to see a frost/freeze with temps falling around or below freezing. Upper ridge will then shift east into the Plains with dry weather and a warming trend expected through mid next week. && .AVIATION...(For the 18Z TAFS Through 18Z Thursday) Issued At 1127 AM MDT Wed Oct 4 2023 A weak disturbance crossing the area tonight will bring isolated showers and a period of breezy to windy northwest winds. LCL MVFR CIGS may occur with any showers, and also over and near the northern Black Hills. Otherwise, VFR conditions will prevail through the TAF period. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION...JC AVIATION...10