Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 030948

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
248 AM MST Sat Dec 3 2016

.SHORT TERM...(Today Through Sunday Night)
Issued at 231 AM MST Sat Dec 3 2016

Upper level analysis has trough over the western and north
central CONUS, with a closed low over the gulf of California.
Skies are mostly clear across the area with a mid level stratus
deck lifting into south central SD at the moment. Some patchy fog
also evident across central SD. With surface high pressure over
the region, winds are light and variable across the SD plains, but
weak lee trof producing some breezy southerly winds across
northeast WY. Temperatures at 2am are in the teens and 20s.

Today...Upper trough will cross the region today, with increasing
clouds and winds becoming more westerly. Some limited moisture may
allow for a few snow showers or flurries over parts of
northeastern WY, the Black Hills, and northwestern SD, but most of
the CWA should remain dry. Temperatures will warm into the mid 30s
and lower 40s. With breezy winds and mostly cloudy skies, lows
tonight will be in the 20s.

Sunday...Weak shortwave upper ridge crosses the area on Sunday,
with partly sunny skies expected. West to southwest boundary layer
flow will advect in slightly warmer temperatures, with highs in
the upper 30s to mid 40s expected. The warm and dry weather is
short lived, as a strong system approaches the area Sunday night.
Chances for snow increase across northeastern WY after midnight.
Low temperatures will fall into the teens and 20s.

.LONG TERM...(Monday Through Friday)
Issued at 231 AM MST Sat Dec 3 2016

Arctic cold front plunges into the CWA Monday as upper trough
carves out across central North America and 1050mb surface high
builds into the northern Plains for the middle of the week. -SN
will occur along and behind the front as moisture squeezes out and
weak synoptic forcing crosses the CWA. Accumulations look to be
minor. Main effect will be temperatures 20-30F below normal with
wind chills dropping to -10F to -25F at times; perhaps colder
depending on wind speeds Tuesday and Wednesday afternoon.

Warmer air builds into western portions of the CWA Friday and most
areas Saturday.


.AVIATION...(For the 12Z TAFS Through 12Z Sunday Morning)
Issued At 231 AM MST Sat Dec 3 2016

Patchy IFR VSBYS due to FG possible through this morning over
western SD. Local MVFR CIGS possible due to ST/SC this morning.
Outside of these areas, VFR conditions expected most areas through
the forecast period. Local MVFR CIGS/VSBYS possible this
afternoon/tonight across the north -SHSNRA possible this
afternoon/early evening.




LONG TERM...Helgeson
AVIATION...Helgeson is the U.S. government's official web portal to all federal, state and local government web resources and services.