Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 132311
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
411 PM MST Sat Jan 13 2018

.DISCUSSION...(This Evening Through Saturday)
Issued at 151 PM MST Sat Jan 13 2018

Current surface map places warm front across southeast Montana,
through the Black Hills, into western Nebraska. Shortwave in
northwest flow, is bringing some light snow across much of
northeast Wyoming/western South Dakota. Steep low level lapse
rates resulting in upslope enhancement for northern Black Hills.
Shortwave quickly dives southeast tonight, with snow ending
across much of the area this evening. May be some lingering
upslope snow in the northern Black Hills past midnight. Warm front
continues to push east overnight with very little drop off in
temperatures across northeast Wyoming and the Black Hills. Western
South Dakota plains should see slowly rising temperatures
overnight. Temperatures near to slightly above average on Sunday,
especially across southwest South Dakota. Upper trough rotating
around the west side of a Hudson Bay low will drop through the
Dakotas Sunday afternoon into Sunday night. This will bring
another round of light snow as arctic front drops through the
forecast area. Will eventually need wind chill headlines Sunday
night as wind chill drops to around -35F in far northwest South
Dakota. With 1050mb high across across the Dakotas Monday, will be
another cold day.

Models in decent agreement for the middle of the week with upper
level ridge shifting into the northern plains. Warm front will
bisect the forecast area Tuesday...with some uncertainty as to how
fast plains of western South Dakota will warmup. Above average
temperatures and dry weather expected Wed-Fri. Increasing chance
of precipitation going into the weekend as upper trof moves into
the plains.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Sunday Evening)
Issued At 402 PM MST Sat Jan 13 2018

Widespread MVFR conditions in light snow from NE WY through
western SD, with IFR conditions around the Black Hills, will
gradually improve by later this evening. However, areas of MVFR
cigs will likely persist through the night into Sunday morning.
Next arctic front moves through late Sunday morning with MVFR
conditions in light snow spreading south behind the arctic front.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION...7
AVIATION...Johnson


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