Area Forecast Discussion
Issued by NWS Rapid City, SD

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FXUS63 KUNR 232327

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
427 PM MST Fri Feb 23 2018

.DISCUSSION...(This Evening Through Friday)
Issued at 125 PM MST Fri Feb 23 2018

A large upper trough stretches across the central and
western CONUS, with southwest flow over the CWA. Satellite shows
mostly clear skies over western SD and northeastern WY. At the
surface, high pressure sits over SD. Winds across the CWA are 5-10
mph, and temperatures are in the single digits and teens, with some
20s and 30s in the Hills. Smoke from Black Hills pile burning
continues to linger around the Rapid City area under the inversion.

Snow will begin spreading across the area tonight as the initial
wave associated with the upper trough crosses the northern plains.
Most of the snow will be across eastern SD on Saturday, where there
will be better moisture and forcing. South central SD may see a
couple inches of snow by Saturday evening, with lesser amounts
farther west. Secondary impulse will move through Sunday, but mostly
dry weather is expected, except for the possibility of a few upslope
snow showers over the northern Hills.

Mainly dry conditions are expected next week under somewhat zonal
flow. Models are showing a low pressure system developing over
southern CA early in the week, but most of the energy associated
with this system should stay south of the CWA. Temperatures will
remain slightly below average this weekend into next week, with
highs in the 30s.


.AVIATION...(For the 00Z TAFS Through 00Z Saturday Evening)
Issued At 425 PM MST Fri Feb 23 2018

VFR conditions should continue through approximately 03z tonight.
After this, MVFR cigs/IFR vsbys will overspread portions of
northeastern WY and southwestern SD as snow enters the area from the
south. Reduced cigs/vsbys will persist over the SD Plains through
much of the day tomorrow before improving by 21-00z.

High-resolution models are trending farther east with the bulk of
this snowfall. As a result, have chosen to remove mention of -SN
from the KRAP TAF for now. If KRAP does happen to see snowfall, it
would likely be in the 12-15z time frame Saturday morning.
Conditions at KGCC should remain VFR through the TAF period.




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