Area Forecast Discussion
Issued by NWS Rapid City, SD

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000 FXUS63 KUNR 042326 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 426 PM MST Thu Mar 4 2021 .DISCUSSION...(This Evening Through Thursday) Issued at 153 PM MST Thu Mar 4 2021 20z surface analysis had lee trough from central MT into eastern WY. Stationary front from western ND into central NE. East/southeast flow over the CWA as thin cirrus pushes through in response to upper low spinning over eastern CO. Tonight, upper low spins east well south of the CWA. Nearly stationary front may slip eastward overnight. Low/mid 30s Td/s along boundary slip westward into the eastern reaches of the CWA. Forecast lows east of the Black Hills in the mid 20s to lower 30s so some fog/stratus may develop. NAM most aggressive with fog/stratus. If this happens, it may have an effect on temperatures Friday from KD07 to KPHP to KICR. Friday/Saturday, upper ridge dominates with spring-like temperatures. Morning fog/stratus may affect temperatures over eastern reaches of CWA each morning, but northeast WY into far northwest/southwest SD should reach guidance forecast. Some warmer than guidance readings possible Saturday afternoon given thermal ridge/downslope southwest boundary layer flow. A few records may be in jeopardy. Upper trough moves through Saturday night pushing a dry cold front through the CWA. Sunday through Tuesday, southwest flow aloft and less of a cooldown compared to previous ensemble guidance. Temperatures will remain 10-15F above normal. Tuesday night through the end of the week, mean upper trough develops over the Rockies, extending into the plains states. This trend is warmer than previous probabilistic guidance along with less moisture. Still looks like "typical" March weather with some snow at times, particularly at night. && .AVIATION...(For the 00Z TAFS Through 00Z Friday Evening) Issued At 421 PM MST Thu Mar 4 2021 VFR conditions will continue through the evening and overnight hours for much of the area. Light, easterly flow across portions of the central/western SD plains may result in the development of fog and low clouds. MVFR/IFR conditions will be possible with any fog that develops. However, do not expect that fog will reach KRAP or KGCC. Fog will diminish Friday morning with VFR conditions across the region. && .FIRE WEATHER... Issued At 153 PM MST Thu Mar 4 2021 Unseasonably warm weather will occur Saturday with highs in the 60s to lower 70s and minimum RHes dropping into the 20s - some upper teens over the Black Hills. Gusty south/southwest winds will occur. Elevated fire weather conditions expected. If it looks a little drier/warmer, a Fire Weather Watch/Red Flag Warning may be needed. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ DISCUSSION...Helgeson AVIATION...Eagan FIRE WEATHER...Helgeson

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