


Area Forecast Discussion
Issued by NWS Rapid City, SD
Issued by NWS Rapid City, SD
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285 FXUS63 KUNR 141116 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 516 AM MDT Tue Oct 14 2025 .KEY MESSAGES... - Unsettled weather this week with gusty winds at times - Isolated severe thunderstorms Wednesday night - Best chance of rain later Wednesday into Thursday && .DISCUSSION...(Today Through Monday) Issued at 200 AM MDT Tue Oct 14 2025 07z surface analysis had high pressure from southern MB into the Ohio Valley. Moderate pressure gradient on the back side with gusty southeast winds at times. Water vapour loop had upper low just off the CA coast with speedy southwest flow over the northern Plains. Embedded shortwave spawning showers from northwest into southeast SD per regional radar loop early this morning. Looking upstream, several wiggles noted ahead of upper low. Disposition of upper low the main forecast concern. Through Thursday, upper low will move east today and then eject northeastward into the northern Plains by Thursday. A series of weak shortwaves ahead of it will bring a few showers to fruition. Sustained southeasterly upslope flow will eventually lead to a stratus fest, especially from the Black Hills eastward. Upslope fog not out of the question tonight given forecast boundary layer moisture profiles. Surface low will develop over eastern CO Wednesday per approach of upper low. This will focus narrow band of weak buoyancy over the CWA Wednesday night. Plenty of shear, so isolated severe thunderstorms could occur, especially if they emanate from better looking thermodynamic environment southwest of the CWA. Latest guidance is hinting at a signficant dry slot over the CWA by Thursday, which may cutoff PoPs earlier than current forecast portrays. NBM probability of >0.25" QPF over the next 3 days is 50-80%, highest over northwestern SD. Temperatures will be near guidance in the west where better solar insolation may develop during the day, but potentially lower over western SD where upslope flow/clouds will temper potential temperatures. Friday into the weekend, northwest flow aloft becomes an upper ridge leading to warmer weather for most folks. A colder upper trough may move in for the first half of next week. && .AVIATION...(For the 12Z TAFS Through 12Z Wednesday Morning) Issued At 513 AM MDT Tue Oct 14 2025 Isolated/scattered showers over western SD will shift east today and become more isolated. Additional showers will develop tonight as southeasterly upslope flow persists. Local MVFR/IFR ceilings over south-central SD will slowly spread westward today and become more widespread, invading the Black Hills area and KRAP terminal by 03z and then eventually KGCC after the forecast period. Patchy to areas IFR fog may develop after 03z. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION/KEY MESSAGES...Helgeson AVIATION...Helgeson