Area Forecast Discussion
Issued by NWS Rapid City, SD
Issued by NWS Rapid City, SD
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092 FXUS63 KUNR 010900 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 300 AM MDT Sat Jun 1 2024 .KEY MESSAGES... - Warming up this weekend with chances of showers and thunderstorms at times across the Black Hills and areas to the east. Some storms could be strong to severe over the weekend. - Warm weather expected for much of next week with drier conditions mid to late week. && .DISCUSSION...(Today Through Friday) Issued at 300 AM MDT Sat Jun 1 2024 Current surface analysis shows weak high pressure over western/central SD, with weakening front to the south and east of the region. Upper level analysis shows low pressure still over central Canada, with trough extending south into the northern Plains. Another trough is located over the lower MS river valley, with ridging in place over the Pacific NW. Skies are clear to partly cloudy in most areas, with some showers/storms over western NE into far southwest SD as mid level theta-e advection increases. Temps are in the 40s and lower 50s with light winds. Warmer air is starting to push into the region tonight as the surface high begins to shift east of the area this morning. Highs today will reach into the 70s across much of the area, with 60s and lower 70s over the Black Hills. Winds will turn to the south and southeast later this morning and afternoon, but are expected to remain relatively light. Showers and storms will likely continue to develop further north and east into southwest and south central SD early this morning. Brief heavy rain and perhaps some small hail are possible with any stronger cells. This morning activity may end up limiting potential for additional storms later today across these areas, but some additional development is possible this afternoon into tonight from the Black Hills and southwest SD to south central SD. MLCAPE values of 500 to near 1500 j/kg are progged for areas from the Black Hills to south central SD as low level moisture increases, highest values toward south central SD. Shear looks favorable for supercell development if storms can develop. Large hail would be the primary threat from stronger storms, but strong winds are also possible. The more favorable environment looks to be south of the forecast area, across the central high Plains. Additional showers and storms are also possible late tonight into early Sunday across mostly western and south central SD as low level jet intensifies over western NE into the western Dakotas. For Sunday, a more widespread chance for showers and storms is expected as a cold front and stronger disturbance aloft approach the area. Highs on Sunday will range from the lower 70s over northeast WY and the higher Black Hills to at least the mid 80s over south central SD. Timing of the cold front passage looks to be early enough in the day to limit severe potential to areas mainly east of the Black Hills and especially into central SD, where CAPE values are progged to exceed 2000 j/kg in the afternoon ahead of the front. Strong winds and hail would be the main threats as a line of storms could eventually develop toward central SD later in the afternoon. The front will generally wash out to the southeast of the area Sunday night with a quick return to warmer temps for Monday. Another cold front and stronger shortwave trough will swing through south central Canada and the northern Plains later Monday into Tuesday. This system should bring the best chances for showers and storms from northeast WY to northwest SD. Any severe threat looks rather low at this time. For the rest of the week, a building ridge over the western US and a large scale trough over the eastern half of the US 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 06Z TAFS Through 06Z Saturday Night) Issued At 1027 PM MDT Fri May 31 2024 Showers and isolated thunderstorms are expected after 06z tonight through Saturday morning across southwest South Dakota...which may include the Black Hills area up to Interstate 90. This precipitation will move off toward central SD through the morning tomorrow. More isolated to scattered thunderstorms are expected across the area tomorrow afternoon and evening. MVFR conditions are possible in and near any storms. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION/KEY MESSAGES...26 AVIATION...13