Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 281122

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
422 AM MST Tue Feb 28 2017

.SHORT TERM...(Today Through Wednesday Night)
Issued at 346 AM MST Tue Feb 28 2017

Upper level analysis has trof crossing the Northern Rockies with
unsettled southwest flow across the Northern Plains. Skies are
cloudy across much of the Dakotas with upper shortwave crossing
the area at the moment. Regional radar shows wide area of snow
across Northwest SD. At the surface, weak frontal boundary extends
from southeast Montana into southern South Dakota with light east
to northeast boundary layer flow. Lower atmosphere has moistened
up in the last several hours, leading to widespread stratus and
fog across much of western SD. Temperatures at 3am are mainly in
the 20s.

Today...Unsettled southwest flow aloft will continue through
tonight, with a couple of weak disturbances bringing areas of
snow. Current shortwave disturbance will continue to move across
northern portions of the CWA, eventually exiting into central
South Dakota this afternoon. Next shortwave will slide through
late this afternoon into this evening with likely snows across the
Black Hills area. Around an inch of snow accumulation will be
possible across these areas with both of these systems.
Temperatures will be slightly cooler today, mainly in the 30s for
highs and teens to lower 20s for lows.

Wednesday...Upper trof finally shifts east of the area with
northwest flow taking over. Drier conditions expected with
temperatures remaining slightly below average.

.LONG TERM...(Thursday Through Monday)
Issued at 346 AM MST Tue Feb 28 2017

Northwest flow continues into Thursday as upper ridge begins to
build across the west. Dry weather is expected again on Thursday
with near average temperatures. Western ridge will begin to build
over the region Friday and then continue into the weekend.
Temperatures will be above average Friday through the weekend,
with the warmest temperatures over the weekend. Some model
differences on the timing of cold fronts later in the weekend and
into early next week. EC is coming into better agreement with GFS
on keeping Sunday mild, before a strong cold front and upper level
disturbance brings colder temps and chances for pcpn Sunday night
into Monday morning. Mild conditions look to continue into next


.AVIATION...(For the 12Z TAFS Through 12Z Wednesday Morning)
Issued At 346 AM MST Tue Feb 28 2017

A couple of weather disturbances will bring low stratus, fog, and
snow across Northeast WY, the Black Hills, and northwest SD
today. Widespread MVFR/IFR conditions can be expected, with local
LIFR conditions likely in fog and snow through midday. MVFR/IFR
conditions will continue through Tues evening across the Black
Hills area as second system moves through.




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