Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 182308

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
508 PM MDT Tue Oct 18 2016

.SHORT TERM...(This Evening Through Wednesday Night)
Issued at 243 PM MDT Tue Oct 18 2016

Current surface analysis shows a nearly stationary cold front
across northern MN, ND, and northern MT. Weak high pressure is
centered to the southwest of the area. Upper level analysis shows
near zonal flow over the northern US, with strong jet in place
from CA to the Great Lakes region. Skies are mostly sunny to
partly cloudy across the area with temps mostly in the mid 50s to
mid 60s. A few light showers and sprinkles have developed from the
Black Hills to the west central SD plains this afternoon. This
activity should end around sunset. Winds are from the west-
northwest at 5 to 15 mph, with some higher gusts over northwest
and central SD.

Unsettled weather is expected over the short term period as a series
of disturbances move across the area through Wednesday night. The
strongest wave will impact the area Wednesday afternoon into
Wednesday night, bringing a good chance for rain from the Black
Hills area to portions of central SD.

For tonight, clouds will increase from northeast WY to southern SD
as a weak disturbance moves across mostly southern WY and Neb. Some
rain and snow showers are possible overnight into early Wednesday
for areas mainly south of I-90, with the best chances over far
southern SD. Lows will mostly be in the 30s, with some 40s over
south central SD.

As one disturbance exits south central SD in the morning, another
stronger shortwave disturbance will bring increasing clouds and
chances for pcpn over western areas by midday. The best chances for
showers will be in the afternoon and evening hours. This wave will
track a bit further north than tonight`s disturbance, so chances for
showers will be fairly widespread, with the best chances from the
Black Hills to south central SD. There is enough instability
forecast for the Black Hills and southwest SD to include an isolated
thunderstorm mention in the afternoon. With clouds and pcpn around,
temps will be cooler than today, with highs mostly in the 50s, some
40s over portions of northeast WY and the Black Hills. A little snow
could mix in with rain over some areas Wednesday night before pcpn
ends, especially over the Black Hills and the Pine Ridge. Lows will
be in the upper 20s and 30s.

.LONG TERM...(Thursday Through Tuesday)
Issued at 243 PM MDT Tue Oct 18 2016

Dry weather is expected from Thursday through Tuesday
as a broad upper ridge develops over the CONUS. High temperatures
will be near or slightly warmer than average through the period.
Model solutions diverge greatly after the middle of next week, but
point to a more active weather pattern.


.AVIATION...(For the 00Z TAFS Through 00Z Wednesday Evening)
Issued At 506 PM MDT Tue Oct 18 2016

Rain or snow showers are possible later tonight across parts of
northeastern Wyoming and southwestern South Dakota where local
MVFR ceilings are possible. Otherwise, area of stratus may move
into northwest South Dakota overnight with IFR ceilings.  VFR
conditions elsewhere.




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