Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 281955

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
155 PM MDT Sun May 28 2017

.DISCUSSION...(This Evening Through Sunday)
Issued at 153 PM MDT Sun May 28 2017

19z surface analysis had low over southern SK with trough into NE
and another into eastern MT. Upper low spinning over the southeast
SK with pinwheeling disturbances rotating around it into the
Dakotas. Upper/surface features tapping into 250-500J/kg MLCAPE to
produce another round of popcorn -TSRA this afternoon/evening.
Activity focused on Black Hills terrain and surface trough. A few
gusty storms will occur given 20-35kt 850mb winds. Activity will
end by 06z tonight as subsidence/drying takes hold. Temperatures
tonight will be tricky with dry air and clearing skies creating
widely varying readings.

Monday and Tuesday, modest upper ridge will bring a couple of nice
days. Little instability noted with general synoptic scale
subsidence supporting continued dry forecast. Temperatures will be

Wednesday through Sunday, split flow regime develops with
increasingly active northern branch of westerlies. PoPs will be
largely diurnal, except perhaps by next weekend when decent
cyclonic/northwest flow develops. Temperatures will be 5-10F above
normal on average.


.AVIATION...(For the 18Z TAFS Through 18Z Monday)
Issued At 1112 AM MDT Sun May 28 2017

Mainly VFR conditions are expected today. Some MVFR conditions
will be possible near showers and thunderstorms. A few storms may
be strong to severe. Northwest winds will be breezy this
afternoon, especially across northwestern SD.




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