Area Forecast Discussion
Issued by NWS Rapid City, SD

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690
FXUS63 KUNR 300351
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
851 PM MST Tue Nov 29 2016

.UPDATE...
Issued at 834 PM MST Tue Nov 29 2016

Closed low continues to support broad lift and strong ll winds
over the region. Main area of lift has shifted east toward central
SD with ll flow starting to dry over the far west. This has ended
snow over much of the far west away from the Black Hills. Upslope
forcing continues over the Black Hills, although in a diminishing
capacity as the ll/s dry and forcing shunts out of the DGZ.
Biggest issue continues to be the wind across the area, with
several areas still gusting to 40-50 mph on the plains. This will
support blowing and drifting snow across the area most of the
night. Downgraded most of the plains to an adv given lack of sig
vis restriction in blowing snow with not much more snow expected,
mainly an adv for areas blowing/drifting snow. Retained the
warnings over the Black Hills for treacherous conds with an
additional 1-3 inches (high elevations), several inches on the
ground supporting blowing/drifting snow, and several roads closed.
Also retained the warning in the far NE given additional 1-3
inches overnight, with deeper snow pac and a better chances for
sig blowing snow at times. Also ext all areas (except for the BH)
through 8 am MST.

&&

.SHORT TERM...(This Evening Through Wednesday Night)
Issued at 136 PM MST Tue Nov 29 2016

Stacked low has remained stationary over wrn MN today and
continues to result in gusty northwest winds and snow for much of
the cwfa, with heavy upslope snow in the northern Blkhls and
nrn/nern foothills. Very pronounced downslope hole persists from
Rapid City through far swrn SD. Secondary upslope band of snow extends
from far ern Fall River county into scntrl SD. Snow totals around
2 feet have been reported at both the Blind Park and North Rapid
Creek Snotel sites. Extremely difficult travel conditions have
resulted in several road closure and no travel advisories around
the nrn Blkhls region. I-90 from Rapid City to Spearfish remains
closed.

Satellite imagery shows some drying working swd through ern MT and
wrn ND. As this drying progresses swd late this evening, expect
snow to slowly decrease in intensity across far western SD. The
upslope snow signature in the nrn Blkhls will likely be the last
to erode, so expect heavy snow to continue there well into the
evening before decreasing. Snow on the SD plains will likely
linger through the night. Winds will slowly diminish tonight as
well, but will still remain strong enough to produce restricted
visibilities in blowing snow, even after the snow decreases. Thus,
will keep current winter weather highlights going through the
night.

Lingering snow will slowly end from west to east during the day
Wednesday as the low pressure system moves ewd from the upper
midwest into the Great Lakes. Breezy northwest winds will
persist with highs in the mid 20s to mid 30s. Surface high will
settle into nern WY and wrn SD Wednesday night.

.LONG TERM...(Thursday Through Tuesday)
Issued at 136 PM MST Tue Nov 29 2016

Dry weather expected late this week and this weekend for most of
the area as drier flow aloft from the west-northwest develops over
the region. Weak disturbances in the flow will bring clouds at
times and possibly a few snow showers from far northeast WY into
the Black Hills. Temperatures will mostly be near average through
the weekend, upper 20s and 30s Thursday and Friday, mid 30s to mid
40s over the weekend. Medium range models have been consistently
showing some arctic air surging into the Northern Plains sometime
in the first half of next week on the backside of a storm system
which is at this time expected to stay south and east of the CWA.
There will still be chances for light snow with the arctic air.
Temperatures look to be well below average Tuesday and at least
the middle of next week.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Wednesday Evening)
Issued At 420 PM MST Tue Nov 29 2016

MVFR/IFR conditions will continue across the much of the area
through the forecast period...with some gradual improvement
expected through tonight. The exception is VFR conditions across
the southern Black Hills and far southwest SD. Strong
northwesterly winds will continue through much of this
evening...with a few gusts to near 50 kt across the west central
SD plains. Winds will begin to gradually decrease later this
evening through Wed.


&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Storm Warning until 5 AM MST Wednesday for SDZ024-025-028-
     072.

     Winter Weather Advisory until 8 AM MST /9 AM CST/ Wednesday for
     SDZ001-012-013-031-032-042>044-046-047-049-073.

     Winter Storm Warning until 8 AM MST Wednesday for SDZ002-014.

WY...Winter Storm Warning until 5 AM MST Wednesday for WYZ057.

     Winter Weather Advisory until 8 AM MST Wednesday for WYZ071.

&&

$$

Update...JC
SHORT TERM...Johnson
LONG TERM...13
AVIATION...JC



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