Area Forecast Discussion
Issued by NWS Rapid City, SD

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007
FXUS63 KUNR 090932
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
232 AM MST Fri Dec 9 2016

.SHORT TERM...(Today Through Saturday Night)
Issued at 230 AM MST Fri Dec 9 2016

High clouds are streaming into the northern plains through
northwest flow, and mid/low clouds are pushing into western and
central SD. Surface high pressure stretches north to south across
much of the central CONUS. Radar has begun to indicate some weak
echoes over southwestern SD. Winds across the CWA are 5-10 kts and
generally from the east, while temperatures at 2 AM are in the
single digits above and below zero. Despite the light winds, wind
chills have dipped below -20 across northwestern SD. Expecting
wind chills to reach -25 to -30 this morning, although low clouds
moving in may keep temps a bit warmer. Will go ahead with a Wind
Chill Advisory this morning for northwestern SD.

Warmer air will begin pushing into the area from the southwest.
Overrunning warm air is expected to produce an area of light snow
across southwestern SD early this morning, transitioning into
central SD today. Accumulations will be minimal. Highs today will
range from near zero across northwestern SD to the teens across
northeastern WY, the Black Hills, and southern SD. Skies will be
mostly cloudy.

Warmer air will continue to move into the region tonight as low-
level winds will become southwesterly ahead of an approaching
trough. As isentropic lift increases, another band of snow is
expected to develop along the baroclinic zone. Forcing strengthens
late Saturday morning and afternoon, but quickly shifts into eastern
SD. Portions of central SD could see around an inch of snow before
noon, with minimal accumulations across the rest of the CWA. Chances
for light snow will continue Saturday night, as a weak upper wave
passes through the region.

Highs Saturday will range from the single digits across northwestern
SD, to the 20s and 30s across northeastern WY, the Black Hills, and
southern SD.

.LONG TERM...(Sunday Through Thursday)
Issued at 230 AM MST Fri Dec 9 2016

Shortwave crossing the area will bring a chance of light snow to
much of the area on Sunday morning...moving off to the east in the
afternoon. Sunday will be the warmest day of the extended forecast
period, although high temperatures will only range from the teens
over parts of northwestern SD to the upper 20s over northeastern
Wyoming and the Black Hills. Another surge of arctic are will
arrive on Monday, with breezy to windy northwest winds and falling
daytime temperatures. Cold temperatures will continue through next
week with even colder air arriving next weekend. Widespread snow
is likely from late Thursday through Friday as the colder air
pushes into the region.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Saturday Morning)
Issued At 230 AM MST Fri Dec 9 2016

Areas of MVFR/LCL IFR conditions in -SN are expected over
parts of southwestern and south central South Dakota this morning
into early afternoon. VFR conditions are then expected into the
evening. Widespread IFR conditions in -SN are expected to develop
aft 06Z tonight.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Chill Advisory until 11 AM MST this morning for SDZ001-002-
     012-013.

WY...None.
&&

$$

SHORT TERM...Pojorlie
LONG TERM...10
AVIATION...10



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