198
FXUS63 KUNR 221933
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1233 PM MST Wed Jan 22 2025

.KEY MESSAGES...

-Moderate to locally heavy snow accumulations in the northern
 Black Hills through tonight, with an additional inch or so on
 the northeast WY plains

-Gusty winds along with areas of blowing snow will diminish
 tonight

-Unsettled and cool into the weekend, drier and warmer weather for
 much of next week

&&

.DISCUSSION...(This Evening Through Wednesday)
Issued at 1215 PM MST Wed Jan 22 2025

Water vapor shows clipper tracking southeast across the Northern
Plains/Upper Midwest with next upstream clipper over central
ALTA/SASK. Upper high is offshore the west coast with ridge
extending into the Pac NW. At the surface, tight pressure gradient
resulting in gusty northwest winds. Snow continues across
northeast WY with persistent upslope snow into the northern Black
Hills, with scattered snow showers across the SD plains.

Snow will continue through much of tonight across northeast WY and
the northern Black Hills, reinforced by the next upstream clipper.
Additional snow amounts overnight around an inch in northeast WY
with several more inches in the northern Black Hills. Most
accumulations on the SD plains should remain light; half an inch
or less. Blowing snow issues should gradually diminish overnight
as winds relax.

Snow should end rather quickly Thursday morning behind departing
clipper, with breezy northwest in the morning slowly relaxing in
the afternoon. Highs most in the 20s, with possibly lower 30s on
the eastern slopes of the Black Hills.

Next trof pushes through Friday into Saturday, with some gusty
northwest winds and light snow. Available moisture should be
considerably less with this trof, so any accumulations will be
light and mainly across northeast WY and the northern Black Hills.
A bit of modified arctic air will push back into the area with
highs Saturday in the mid teens to mid 20s, but it should be
rather short lived with temps rising about 5 to 10 degrees for
Sunday.

Rather flat upper ridge will dominate our weather for much of
next week, with mainly dry and warmer weather expected. However,
with lighter winds aloft, an occasional back door front associated
with any waves embedded in the northwest flow over central Canada
could knock temps at times.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Thursday)
Issued At 1043 AM MST Wed Jan 22 2025

Light snow will continue today and tonight across much of the
area. Widespread MVFR/IFR conditions are expected through much of the
forecast period, improving overnight into Thursday morning.
VFR conditions are expected at times on the leeside of the Black
Hills, including KRAP. Gusty northwesterly winds will continue
today, with gusts to 30 to 45 kt.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory until 5 PM MST this afternoon for SDZ001-002-012-
     013-026-030-031-041-072-073-078.
     Winter Weather Advisory until 8 AM MST Thursday for SDZ024.
WY...Winter Weather Advisory until 8 AM MST Thursday for WYZ057.
     Winter Weather Advisory until 5 AM MST Thursday for WYZ054>056-
     058-060.
&&

$$

DISCUSSION/KEY MESSAGES...Johnson
AVIATION...Dye