Area Forecast Discussion
Issued by NWS Rapid City, SD

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495
FXUS63 KUNR 151658
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
958 AM MST Mon Jan 15 2018

.DISCUSSION...(Today Through Sunday)
Issued at 239 AM MST Mon Jan 15 2018

Current surface map shows 1050mb arctic high dropping south across
southern Saskatchewan. Temperatures range from the single digits
above zero across portions of northeast Wyoming and Black Hills,
to around 10 below zero across northwest South Dakota. With
northwest winds gusting 20-30mph, wind chill values around 30
below across northwest South Dakota. With arctic high over western
Dakotas today, very cold temperatures expected. Highs will remain
below zero across northwest South Dakota. Clear skies and light
winds will allow temps to drop below zero again tonight, with
some lows in the 20s below from northwest into central SD.

Dry weather is then expected through early Friday as ridge over
the west coast moves east through the plains. This will also bring
much warmer weather, especially by Wednesday and Thursday, with
temperatures above average for late week. Southwest flow develops
by the end of the week into next weekend as large scale trough
moves across the western US Friday into Saturday. Medium range
models are showing differences with the specifics of the trough as
it moves into the plains over the weekend. ECMWF/GFS/GEM continue
to show best chance of snow across southern portions of forecast
area. However, ensemble members show wide spread in precipitation
amounts due to N-S spread in storm track. Temperatures will
drop back to near or slightly below average for the weekend.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Tuesday)
Issued At 955 AM MST Mon Jan 15 2018

MVFR to IFR ceilings are lingering across portions of northeast
WY, along the eastern foothills, and toward central SD. These low
clouds may stick around for a few more hours, before gradually
dissipating this afternoon. VFR conditions are expected elsewhere.
NW winds of 15 to 25 kts will persist today across the western SD
plains, before becoming light and southerly tonight.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Chill Advisory until 11 AM MST /noon CST/ Tuesday for
     SDZ001-002-012>014-025-031-032-042>044-046-047-049-072-073.

WY...Wind Chill Advisory until 11 AM MST Tuesday for WYZ071.

&&

$$

DISCUSSION...7
AVIATION...Pojorlie



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