Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 161750

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1050 AM MST Sat Dec 16 2017

.DISCUSSION...(Today Through Friday)
Issued at 340 AM MST Sat Dec 16 2017

Northwest upper flow continues across the northern plains...but is
becoming more westerly this morning as an upper trough crosses the
western CONUS. Forcing ahead of this wave will result in snow
developing across Wyoming over the next few hours. This snow will
develop eastward into northeast Wyoming this morning...and into the
Black Hills late this morning into the afternoon hours. Models are
showing generally 1 to 3 inches of snow across these areas...with
the maximum of 4 inches across southern Campbell. Generally 2 or 3
inches of snow...possibly up to 4 expected across the
Black Hills, but this will be more spread out over 18 hours or
so. Not planning on expanding the current advisory. Aside from
some lingering snow showers, drier weather is expected Sunday as
the main trough axis crosses the CWA. Warm air advection will
develop with highs reaching the 40s to mid 50s by Monday and
continuing through Wednesday. A cold front will cross the region
sometime late Wednesday into Wednesday night bringing colder air
to the area. This system will also bring good chances of snow to a
wide area...though QPF amounts won`t be very high. At this time
it looks like 1 to 3 inches of snow is what most areas will
receive. Cooler than average temperatures are expected to continue
through the rest of the week.


.AVIATION...(For the 18Z TAFS Through 18Z Sunday)
Issued At 1046 AM MST Sat Dec 16 2017

IFR (local LIFR) conditions due to low stratus and -SN will
persist through evening around the Black Hills and west. Expect
MVFR conds east of the Black Hills with areas of IFR conds in
snow. Mainly VFR to high end MVFR can be expected over the NE
third. IFR to MVFR conds will linger through the night SW third,
esp around the Black Hills, with some improvement NE-SW as drier
air works into the region.


WY...Winter Weather Advisory until midnight MST tonight for WYZ055.



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