Area Forecast Discussion
Issued by NWS Rapid City, SD
Issued by NWS Rapid City, SD
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036 FXUS63 KUNR 290431 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 1031 PM MDT Sun Apr 28 2024 .KEY MESSAGES... - Rain/showers gradually end from west to east across western and south central SD late today and tonight. - Near to above average temperatures return for the first half of the week, with chances for showers and gusty winds Monday night into Tuesday. - Cooler and unsettled weather develops for the middle and latter parts of the week, with some higher elevation snow possible. && .DISCUSSION...(This Evening Through Sunday) Issued at 245 PM MDT Sun Apr 28 2024 Current surface analysis shows low pressure system centered over western IA right now, with another area of low pressure over southeast AB and a warm front extending south across eastern MT into WY. Upper level analysis shows low located over south central SD, moving slowly northeastward. Swath of rain and showers extends west and northwest of the low to the Black Hills area, with the heaviest rainfall today being just east of the Black Hills into portions of central SD. Further west, a good amount of sunshine has been noted across much of northeast WY. Temps this afternoon range from the 40s over much of western SD to around 60 over Campbell County, WY. Some 30s have been noted over the Black Hills, with a few flurries over some of the higher elevations. Winds have mostly been from the north to northeast at 10 to 15 mph this afternoon. Rain/shower activity will gradually shift eastward out of western SD late today and tonight, exiting far eastern areas later tonight. Additional rainfall amounts will be on the light side. Weak ridging aloft builds over the region later tonight and Monday, with warm front sliding eastward across the area during the same time. Highs will reach into the 60s to around 70 degrees in most areas. Humidities will drop to 15 to 20 percent in the afternoon across southern portions of northeast WY to extreme southwest SD as southwesterly winds develop, but sustained speeds are not expected to exceed 15 mph or so. A few showers could develop over the Black Hills in the afternoon. The rest of the week looks to be unsettled at times as a series of systems cross the region in near zonal flow. The next one arrives Monday night with the associated upper low passing north of the area. Shortwave energy passing south of the low will bring chances for showers to most of the area Monday night into Tuesday. Temps could become cold enough for a little light snow over the higher Black Hills. Drier air will move into the area on Tuesday on the southwest side of the system behind a cold front, with humidities dropping to 15 to 25 percent across northeast WY and much of western SD. Gusty west-northwest winds will develop, especially across far northwest SD, where chances for winds reaching advisory criteria (gusts over 45 mph) are near or above 50 percent at this time. Another upper level trough is progged to move farther south across the region Wednesday night and Thursday. Medium range models differ some on the track of this system, with GFS further south than the EC and Canadian. Better chances for beneficial rainfall still look to be across southern portions of the forecast area, but this potential will likely shift some across the area with time. Depending on the track, temps could become cold enough later Wednesday night and Thursday for some accumulating snow across at least the higher elevations of the Black Hills and possibly northeast WY as well. Yet another system could bring showers Friday night and Saturday, with the potential for snow across at least the higher elevations. As far as temperatures go, near to slightly above temps Monday through Wednesday will become near to below average later in the week and into next weekend. && .AVIATION...(For the 06Z TAFS Through 06Z Monday Night) Issued At 1025 PM MDT Sun Apr 28 2024 Light rain will continue to exit western SD overnight. MVFR/IFR conditions across the western SD plains will improve, except where fog develops. Fog is still expected to remain east of KRAP. Fog will dissipate early Monday morning, and then widespread VFR conditions are expected through rest of the forecast period. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION/KEY MESSAGES...26 AVIATION...Pojorlie