Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 140515

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1015 PM MST Fri Jan 13 2017

.SHORT TERM...(This Evening Through Saturday Night)
Issued at 1258 PM MST Fri Jan 13 2017

The arctic air continues to erode early this afternoon across
much of the region, especially nern WY through the Blkhls and swrn
SD, as center of arctic high has shifted into the western Great
Lakes Region. Some readings already into the 40s in the Blkhls and
ern foothills. Water vapor shows mainly dry zonal flow across the
nrn plains.

Even warmer temps expected on Saturday as Pacific air continues to
filter into the region. However, temps will struggle to warm into
the 20s on the nwrn SD plains where deeper snow cover exists. Mostly
sunny skies expected along with relatively light winds.

.LONG TERM...(Sunday Through Friday)
Issued at 1258 PM MST Fri Jan 13 2017

An upper level low will move from far northern Mexico Sunday
morning to the southern and central plains on Monday. Some model
disagreement on the exact track of the storm, especially as it
moves into the plains on Monday. EC continues to be an outlier,
with a further north and west movement of low compared to NAM,
GFS, and Canadian models. The latter three all show a northern
stream shortwave that will help to push the low at least a bit
further east Monday and Monday night, keeping most or all pcpn
south and east of the forecast area. Will lean forecast toward the
better consensus and just keep a chance for pcpn over south
central SD for Sunday night and Monday. However, if pcpn does make
it into south central SD, there would likely be some freezing rain
Sunday night/early Monday before any pcpn becomes all snow.

Otherwise, a mainly dry and mild weather pattern can be expected for
much of next week. Ridging will help to bring above average
temperatures across the CWA by midweek. Snow cover will limit
temperature potential in some areas, especially to the northeast of
the Black Hills, where deeper snowpack is in place. The warmest days
look to be Wednesday and Thursday, with highs in the upper 30s and
40s. Some 50s look increasingly likely over the eastern slopes of
the Black Hills and into the foothills if westerly winds develop as
expected. Medium range models are in pretty good agreement at this
point on the next system ejecting out of the western states on
Friday, with increasing chances for mostly snow Friday into Saturday
as some colder air also builds back into the region.


.AVIATION...(For the 06Z TAFS Through 06Z Saturday Night)
Issued At 1014 PM MST Fri Jan 13 2017

VFR conditions expected across most of the area through Saturday
evening. Patchy IFR/LIFR vis are possible over northeast WY into
far southwest SD late tonight/early Saturday.




SHORT TERM...Johnson
AVIATION...JC is the U.S. government's official web portal to all federal, state and local government web resources and services.