Area Forecast Discussion
Issued by NWS Rapid City, SD
Issued by NWS Rapid City, SD
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140 FXUS63 KUNR 292017 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 217 PM MDT Sat Jun 29 2024 .KEY MESSAGES... - Chance for isolated storms Sunday with the possibility of a strong to severe storm or two in northeastern WY. - Elevated fire weather concerns over northeastern WY Sunday afternoon. - Chance for storms on Monday with strong to severe storms possible, especially towards central SD. - Unsettled weather will continue through the week with near daily chances for showers/storms. && .DISCUSSION...(This Evening Through Saturday) Issued at 216 PM MDT Sat Jun 29 2024 It`s shaping up to be a pleasant afternoon across much of the CWA with temperatures in the mid 60s to 70s. Skies are mostly clear across northeastern WY into southwestern SD with patchy cloud cover over northwestern into south central SD. WV imagery depicts broad ridging over the western US with dry air mass in place across much of the central and northern plains. Sfc analysis depicts large sfc high over the northern plains. Moisture advection from a LLJ coupled with forcing from a weak impulse will bring the potential for isolated thunderstorms across western SD late tonight into the early morning hours. Lee trough develops through the day Sunday with the tightening pressure gradient over the western SD plains lending to strong southerly winds. Gusts may approach advsy level in some spots but coverage and duration of these gusts preclude any issuance of an advsy at this time. Temperatures tomorrow will be much warmer than today with highs in the upper 80s to 90s across much of the area. Weak wave crosses the region late in the afternoon, while low level moisture will be decent across the western SD plains thanks to the southerly flow - drier air at the mid levels will result in a strong cap which will limit any storm development. Better chances for storms will be out in northeastern WY along the dryline with a narrow corridor of 1500-2500 J/kg MUCAPE. While the potential for storms are better in WY, they`re still not great. Fcst soundings over northeastern WY still depict dry air at the mid levels with very dry air at the sfc. If anything does get going, 0-6 km shear values of 40-50kt will be supportive of strong to marginally severe storms. Convection will make its way into western SD by the evening hours, though strength and coverage will be limited due to aforementioned conditions. Afternoon RHs over northeastern WY will drop into the teens to low 20s. The very hot and dry conditions coupled with breezy southerly flow and the potential for afternoon convection will result in elevated fire wx concerns across portions of Campbell and Weston Counties in northeastern WY. Upper level trough with attendant front will cross the region Monday, bringing chances for storms to the region once more. Severe threat will be better Monday afternoon, especially towards central SD where deeper moisture will be available. Upper trough will move to the east by the midweek with quasi- zonal flow setting up over the region. Temperatures will moderate with highs in the 70s to 80s for most of the week. Impulses riding along the flow will result in daily chances for showers and storms. && .AVIATION...(For the 18Z TAFS Through 18Z Sunday) Issued At 1120 AM MDT Sat Jun 29 2024 Lingering areas of MVFR cigs from far northeast WY to northwest SD will become VFR during the early afternoon, with clouds gradually decreasing across northern and eastern portions of the area through the afternoon and early evening. VFR conditions are expected tonight into Sunday morning, with southeasterly winds becoming breezy from west to east across much of the area later tonight and Sunday morning. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION/KEY MESSAGES...Wong AVIATION...26