Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 222147

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
247 PM MST Thu Feb 22 2018

.DISCUSSION...(This Evening Through Thursday)
Issued at 247 PM MST Thu Feb 22 2018

Deep upper trough is persisting across the western CONUS, with
southwesterly flow over the central Rockies through the northern
Plains and upper Midwest. Broad surface low pressure is deepening
across the central Plains into central South Dakota. KUDX radar
shows snow moving into central South Dakota over the last few hours.
Snow will continue to fall tonight mainly over south central SD
where anywhere from 1 to 4 inches of accumulation are expected. It
still looks like the higher snowfall amounts will be limited to
Tripp County. Will continue with the Winter Weather Advisory for
Tripp until 9 PM CST. Snow will quickly end by mid to late evening.
Lows tonight will drop to around 5 below to 10 above zero. Surface
high pressure and weak upper ridging will build in for Friday. Dry
weather is expected with highs similar to today. The western upper
trough will slide eastward Saturday with a surface low strengthening
near Kansas/Nebraska. Wrap around precip will move into the region,
but mostly stay south and east of the CWA. South central South
Dakota will likely see another round of accumulating snow. Right now
it appears to be another 1 to 3 inches total late Friday night into
Saturday. Generally dry weather is then expected through Sunday and
Monday. Highs will be in the upper 20s into the 30s. Right now
models are indicating some light snow possible Tuesday or Wednesday
as a shortwave trough pushes through.


.AVIATION...(For the 18Z TAFS Through 18Z Friday)
Issued At 1028 AM MST Thu Feb 22 2018

Light snow, and associated MVFR to IFR cigs/vsbys, will gradually
overspread much of the SD Plains through early afternoon. Lower
cigs may extend as far west as KRAP by late afternoon, but IFR
conditions are generally expected to remain east of the terminal.
VFR conditions should prevail at KGCC through the TAF period.


SD...Winter Weather Advisory until 9 PM CST this evening for SDZ049.



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