Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 261122
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
422 AM MST Sat Nov 26 2016

.SHORT TERM...(Today Through Sunday Night)
Issued at 245 AM MST Sat Nov 26 2016

Current surface map shows weak trof across the western Dakotas.
Upper level ridge located across the northern plains with mid/high
clouds across the forecast area. Weak southwesterly flow across
the Black Hills is keeping temperatures in the 40s for
northern/eastern foothills. Another warm day across the area as
low level thermal ridge. Highs around 15F above average.

Upper ridge breaks down tonight with strong trof approaches the
Rockies. The upper trof moves into the northern plains Sunday.
Models in decent agreement with 700-500mb low closing off across
eastern South Dakota late Sunday into Sunday night. Surface low
deepens across central Nebraska and tracks into eastern South
Dakota. Should remain dry across the area for much of Sunday, with
some showers across south central South Dakota late Sunday
afternoon. As upper low closes off, best chance of precipitation
will be along eastern portion of forecast area Sunday night. Will
become windy Sunday night on the plains.

.LONG TERM...(Monday Through Friday)
Issued at 245 AM MST Sat Nov 26 2016

Upper level low will be positioned somewhere to the
east-northeast of the forecast area Monday morning, likely over
eastern SD or southeast ND, then move slowly east-northeast through
the early part of the week. Medium range models still showing some
differences on track of low and extent of eastern movement early in
the week as blocking pattern to the east complicates matters. No
particular model has been consistent, so will continue to use more
of a blend at this point. As the low hangs to the east of the area,
shortwave energy and moisture will wrap around the system, bringing
areas of mostly light snow from Monday through at least Tuesday,
along with gusty northwesterly winds. The best chances for snow
across the plains at this point will generally be across northwest
SD into central SD, especially if the low ends up further north and
east of the CWA early in the week. A prolonged period of upslope
snowfall is likely across the northern Black Hills from sometime
Monday into Tuesday as strong and relatively moist north-northwest
flow remains across the area. Extent of accumulating snowfall there
will depend on how the low tracks and this is relatively uncertain
at this point. However, at least several inches of snow is looking
increasingly likely through the period over the northern Hills.
Elsewhere, accumulations of up to a few inches look possible early
next week from northwest SD into portions of central SD, with light
accumulations possible elsewhere. Gusty winds would cause some
blowing and drifting of any snow that falls.

Improving conditions are expected mid week, but still could see a
few areas of light snow as system slowly departs the region. The
latter part of the week into the weekend is now looking mainly dry.
Temperatures through the week will be near or below average, with
highs mostly in the upper 20s and 30s from Tuesday through Friday.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Sunday Morning)
Issued At 422 AM MST Sat Nov 26 2016

VFR conditions are expected through the period. Breezy
southwesterly winds can be expected across portions of northeast
WY.

&&

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

$$

SHORT TERM...7
LONG TERM...26
AVIATION...26



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