FXUS63 KUNR 240446 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 1046 PM MDT Thu Oct 23 2025 .KEY MESSAGES... - Dry, with warming temperatures through the weekend - Widespread elevated fire weather conditions expected on Saturday, and south & west of the Black Hills on Sunday - Cooler and unsettled Sunday night through Tuesday && .DISCUSSION...(This Evening Through Thursday) Issued at 132 PM MDT Thu Oct 23 2025 19Z upper level analysis has large closed low across southeast Canada, with a ridge building across the Rockies and the Northern Plains. Another weaker closed low is currently spinning over the Four Corners region, producing abundant convection. Across the North Plains, mostly sunny skies are observed, with just a few high clouds moving through. At the surface, high pressure resides across the Northern Plains with a weak warm front draped across the area. Temperatures across the forecast area at 1pm are in the mid 50s to mid 60s, with south to southeast winds at 10 to 20 mph. Upper ridge will build across the Northern Plains over the next couple of days as the weak Four Corners low slides to the south of the forecast area. This Rex Block will produce mainly sunny skies and very mild temperatures for the area through Saturday. High temperatures will be in the 60s on Friday, and winds will remain relatively light out of the south. As a strong upper trof approaches the area on Saturday, southerly winds will increase, along with temperatures climbing into the 70s most areas. Dry atmosphere in place will see relative humidity values fall to around 20% Saturday afternoon. This combination of warm temps, breezy winds and low RHs will put most of the area in elevated fire weather conditions Saturday afternoon. Western upper trof crosses the Rockies on Sunday as strong surface lee trof develops east of the Rockies. Should be one more mainly dry day for Sunday, with temperatures slightly cooler than Saturday. Strong southwesterly flow along with continued dry conditions will keep elevated fire conditions in place across areas south and west of the Black Hills. Models differ a bit on timing and strength of precip moving across the area Sunday night into Monday - regardless, a change in the weather is on tap early next week, with cooler temperatures, chances for precip, and some light snow possible across the higher elevations of northeast Wyoming and the Black Hills. Unsettled and cool weather continues into Tuesday, before system finally exits the area on Wednesday. && .AVIATION...(For the 06Z TAFS Through 06Z Friday Night) Issued At 1045 PM MDT Thu Oct 23 2025 VFR conditions will persist through the forecast period. && .FIRE WEATHER... Issued At 132 PM MDT Thu Oct 23 2025 Upper ridge breaks down across the Northern Plains on Saturday, as strong western trof crosses the Rockies. Strong southerly flow, combined with low relative humidity will produce elevated fire weather conditions across northeast Wyoming and far western South Dakota Saturday afternoon. Strong southwesterly to westerly flow and low RHs continue into Sunday morning, south and west of the Black Hills area. Conditions moderate late on Sunday as cooler air moves back into the region. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION/KEY MESSAGES...15 AVIATION...SE FIRE WEATHER...15