Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 122140

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
240 PM MST Sun Feb 12 2017

.SHORT TERM...(This Evening Through Monday Night)
Issued at 240 PM MST Sun Feb 12 2017

Current surface analysis shows high pressure centered over
southern Neb. Upper level analysis shows near zonal flow across
the northwest and north central US, with low pressure cut off from
the main flow across the southwest US and northwest Mexico. Skies
are clear across the area with temps in the upper 30s to mid 40s,
warmest generally over snow free areas. Southwesterly winds are
breezy this afternoon in some areas, mainly from far northeast WY
to northwest SD.

Quiet wx to continue through the short term period as upper low over
the southwest US tracks well to the south of the region and ridge
builds over the northwest US tonight and Monday. Dry northwesterly
flow aloft will keep skies mainly clear, with some high clouds
passing over later tonight and Monday morning. Lows tonight will be
in the upper teens and 20s. Winds will remain from the west to
southwest tonight. Would not totally rule out patchy valley fog in a
few areas late tonight, especially over far southwest SD and snow
covered areas of northeast WY, but sufficient wind looks to keep the
chances rather low, so will leave out of the forecast. Highs on
Monday will be in the 40s to around 50 degrees with mostly sunny
skies. West to northwest winds will become breezy across northwest
SD by the afternoon.

.LONG TERM...(Tuesday Through Sunday)
Issued at 240 PM MST Sun Feb 12 2017

Ridge over the northwest US early in the week will slowly shift
east into the plains late in the week. A gradual warming trend
will take place through the work week, with the warmest days
looking to be Thursday and Friday in most areas. Highs in the 40s
and 50s Tuesday and Wednesday will rise to the 50s and 60s
Thursday and Friday. Warmest conditions will continue to be from
parts of northeast WY through the Black Hills and southern SD.

As ridge weakens and shifts east of the area over the weekend, some
cooler air will filter in, but above average temperatures are still
expected. Southwest flow on the back side of the ridge could bring a
bit of unsettled weather over the weekend, but models diverge on
specifics at this point, especially later in the weekend. Will go
with some low chances for showers Saturday night and Sunday over
mainly SD at this point. 12z GFS and to a lesser extent the EC are
showing a stronger system possibly impacting eastern portions of the
CWA Sunday night into Monday, with a better chance for mainly rain.


.AVIATION...(For the 00Z TAFS Through 00Z Monday Evening)
Issued At 240 PM MST Sun Feb 12 2017

VFR conditions are expected through the forecast period.




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