Area Forecast Discussion
Issued by NWS Rapid City, SD
Issued by NWS Rapid City, SD
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424 FXUS63 KUNR 142312 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 512 PM MDT Tue May 14 2024 .KEY MESSAGES... -Unsettled through the weekend with periodic chances for showers and thunderstorms, with best chances now through Wednesday morning. -A few strong storms are possible this afternoon and early evening in south central SD. -Seasonal temps through the weekend, with Friday the warmest day. && .DISCUSSION...(This Evening Through Tuesday) Issued at 1231 PM MDT Tue May 14 2024 Water vapor shows upper trof over the Northern Rockies/Northern Plains region with upper ridge over the Pac NW. First upper low within the trof is over southwest SD with the second over southeast ID. At the surface, trof extends from eastern CO northward through the western Dakotas, more specifically in our area extending from just east of Porcupine to northeast of KPHP. Scattered to numerous showers/storms cover northeast WY through the Black Hills into southwest SD early this afternoon. Current upper low over southwest SD will migrate slowly east the rest of this afternoon and evening, with scattered to numerous showers/storms continuing. There is some chance for a few stronger to severe storms across southwest into south-central SD through the afternoon, with the better chance over south-central SD in closer proximity to the surface trof where MLCAPE up to around 1000J/kg exists. Shear is marginal for rotating updrafts, but inverted-V profiles suggest some wind threat. Much of the threat should push east of our area by early evening. Next upper low moves in overnight and Wednesday morning, bringing another round of showers/storms. This activity should decrease from northwest to southwest during the afternoon Wednesday as low shifts east and drier/breezy northwest winds develop. Weak upper ridge in the northwest flow moves through the Northern Plains Thursday/Friday for somewhat drier and warmer temps. Friday looks to be the warmest day as thermal ridge peaks overhead, with many locations climbing into the 80s especially east of the Black Hills. Some showers/thunderstorms will remain possible, mostly diurnally driven and over higher terrain. A series of upper trofs will move through from the weekend through mid next week, typical of springtime weather. An unsettled pattern will result with a swing up/down of temps, but temps will remain relatively close to seasonal averages. && .AVIATION...(For the 00Z TAFS Through 00Z Wednesday Evening) Issued At 508 PM MDT Tue May 14 2024 Showers and isolated storms will continue tonight and into Wednesday afternoon. MVFR/IFR conditions are possible in and near any stronger cores. MVFR ceilings (even transient IFR) are expected at KGCC and NE WY overnight tonight, beginning around midnight and continuing into Wednesday morning. Showers will gradually end from northwest to southeast Wednesday afternoon. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION/KEY MESSAGES...Johnson AVIATION...Pojorlie