Area Forecast Discussion
Issued by NWS Rapid City, SD
Issued by NWS Rapid City, SD
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324 FXUS63 KUNR 012353 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 553 PM MDT Sat Jun 1 2024 .KEY MESSAGES... - Warming up through weekend with chances of showers and thunderstorms at times across the Black Hills and areas to the south/east. Some storms could be strong to severe this weekend. - Warm weather expected for much of next week with drier conditions mid to late week. && .DISCUSSION...(This Evening Through Saturday) Issued at 1238 PM MDT Sat Jun 1 2024 Water vapor shows upper trof axis over the far eastern Dakotas, weak ridge over the Northern Rockies, and next trof over the far western CONUS. At the surface, high is over southern ND with weak surface trof near I-90 across western SD. Early afternoon temps in the 60s/70s with weak easterly flow resulting in some towering cu and a developing thunderstorm over the northern Black Hills. Even though there is ample CAPE/shear near and south of I-90 across western SD, short wave ridging building in is trying to keep a lid on development this afternoon (outside of the Black Hills) and may limit overall coverage. The best locations for development this afternoon/early evening would be across the Black Hills into southwest/south-central SD where a stronger storm or two is possible. Better chance for activity arrives later this evening and overnight as jet streak moves through the weak ridge and modest low level jet develops. On Sunday, upper trof works through the Rockies with a cold front working eastward across our zones. The cold front will likely push through all but central SD by about noon. Given the timing of the front, best severe threat will be across our south-central SD zones in the afternoon to early evening where CAPE/shear will be ample for supercells. This looks to be depicted well by most CAMs. Highs will likely range from the lower/mid 70s in northeast WY to the west of the front, and well into the 80s south/east of the Black Hills. Much of Monday looks mostly dry behind departing upper trof, but temps should rebound quickly as return flow gets going early in the day. However, storms will be possible again by late Monday in our western zones as next trof dives quickly into the Northern Rockies. Storms may linger into Tuesday before trof pushes east. For the rest of the week, a building ridge over the western CONUS and a large scale trough over the eastern CONUS will likely keep our area at least seasonably warm and mostly dry. There is uncertainty with the temp forecast for mid to late week, depending on whether the ridge can eventually progress eastward into the Plains toward the end of the week. && .AVIATION...(For the 00Z TAFS Through 00Z Sunday Evening) Issued At 550 PM MDT Sat Jun 1 2024 Isolated showers and thunderstorms are possible tonight. Scattered thunderstorms are possible Sunday afternoon and evening, especially toward central South Dakota. MVFR conditions are possible near any precipitation. Otherwise VFR conditions will prevail through the forecast period. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION/KEY MESSAGES...Johnson AVIATION...13