Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 210939
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
239 AM MST Sat Jan 21 2017

.SHORT TERM...(Today Through Sunday Night)
Issued at 233 AM MST Sat Jan 21 2017

Some residual rain/snow east of the Blkhls will continue to
diminish early this morning as upper energy shifts further east of
the region. Clouds along with some morning fog will also be on
the decrease today. High temps will be near or a bit above
seasonal averages.

More sunshine along with near average temps expected on Sunday as
the area comes under the influence of weak upper ridge.

.LONG TERM...(Monday Through Friday)
Issued at 233 AM MST Sat Jan 21 2017

Weak upper level ridge shifts east of the area Monday as trough
over the west coast moves into the Rockies. Shortwave energy in
southwest flow ahead of the trough could bring some light snow to
parts of northeast WY and northwest SD Monday afternoon. Highs
will mostly be near average, with above average temps over south
central SD.

Upper trough is progged by most models to move across the Rockies
Monday night and into the central high plains Tuesday morning. 00z
medium range models still having some difficulty on where developing
low will evolve over the central plains on Tuesday. GFS still the
most north of the models, moving a low across far northern Neb,
while the EC still has one tracking further south across southern
Neb. GEM is generally between the two, while the NAM has now entered
the picture at 84 hrs with the low much further west and generally
south of the others at that time. There is general agreement on
moving the low and more significant snowfall into the area a little
later than previous runs and still moving the low across the region
rather quickly Tuesday and Tuesday night. Will continue to use the
blended models with regard to pcpn and snowfall amounts at this
point, which come in lower than yesterday for most areas. Still
plenty of uncertainty this far out on where heavier snowfall with
this system develops over the region, but amounts as high as 6
inches are certainly possible over a portion of the forecast area
based on the more likely tracks. Brisk winds Tuesday into Tuesday
night could produce some areas of blowing snow as well.

Snow will taper off and end from west to east Tuesday night, with
northwest flow aloft in place for the rest of the week. This will
keep temps below average, with breezy conditions at times. Weak
energy passing over the northern Black Hills and Bear Lodge Mts
could produce a few snow showers at times Wednesday into Thursday.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Sunday Morning)
Issued At 233 AM MST Sat Jan 21 2017

Areas of MVFR/IFR conditions along with patchy LIFR and fog can
be expected this morning, especially across northeast WY and east
of the Black Hills toward central SD. VFR conditions are then
expected across much of the area this afternoon and into tonight.

&&

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

$$

SHORT TERM...Johnson
LONG TERM...26
AVIATION...26



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