745
FXUS63 KUNR 111732
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1032 AM MST Thu Dec 11 2025

.KEY MESSAGES...

-Freezing rain continues across northwestern SD this morning with
 up to 0.1" of ice.

-Gusty winds are possible across portions of the western SD plains
 this afternoon with gusts of 45+ mph possible

-Accumulating snowfall possible tonight through Saturday where
 3-5" of snow are possible across northwestern SD and the Black
 Hills.

-Very cold temperatures Friday and Saturday with highs in the
 teens to 20s and lows below zero

&&

.DISCUSSION...(Today Through Wednesday)
Issued at 249 AM MST Thu Dec 11 2025

Current water vapor imagery shows northwesterly upper level flow
bringing decent influx of Pacific moisture into the Northern
Plains. A strong, 130-145kt 300-mb jet stream is situated over the
Northern Plains per 07z upper air analysis. Rain/freezing rain is
ongoing across northwestern into south central SD. This precip
should continue through this morning with areas in northwestern
and central SD picking up additional ice accumulations of up to
0.1". Have made no changes to the current Winter Weather Advisory.

Warm today ahead of the next clipper system with many areas
across the southern half of our CWA seeing temps in the 50s to low
60s. Strong 850-700mb wind max will move overhead late this
morning into this afternoon and will bring a brief window of gusty
winds to the CWA. BUFKIT soundings show the potential for 50kt
gusts to mix to the sfc in our usual breezy spots along the
Piedmont/Sturgis foothills and adjacent plains. HREF ensemble
guidance paint 90+% probs of wind gusts exceeding 45 mph in these
areas. Due to the short duration of these winds, opting to not
hoist any wind headlines for this afternoon.

Colder air moves into the region later this evening into the
overnight hours as cold front pushes southward into the CWA. By
Friday, highs progged to be in the teens to 20s with lows in the
single digits. Colder on Saturday with highs in the single digits
towards central SD and in the 20s over northeastern WY into
southwestern SD. Lows Saturday night will dip below zero across
northwestern into south central SD with wind chills in the
negative teens.

Baroclinic zone will stall out over the region with several weak
impulses agitating the flow. With Pacific moisture continuing to
stream into the region, this should support several rounds of
light precip late tonight through Saturday morning. Precip will
start out as rain before transitioning to snow later tonight as
the cold air pushes into the region. In terms of snow amounts,
have bumped them up slightly from the previous forecast. Most
recent forecast thermal profiles show the DGZ extending up to
700-600 mb in northwestern SD by Saturday morning, pointing at
efficient snow growth and higher SLRs. All in all, northwestern
into south central SD and the Black Hills should see
accumulations of 3-5". Southwestern SD will pick up around 1-2"
of snow. Winter weather headlines may be needed for northwestern
into south central SD and the Northern Black Hills late tonight
through Saturday, however with the ongoing weather will opt to
shunt any headline decisions to the day shift. With the moisture
and easterly upslope flow, could also see some fog Friday into
Saturday.

Upper ridge moves east Sunday with warming trend on tap for late
this weekend into next week.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Friday)
Issued At 1031 AM MST Thu Dec 11 2025

MVFR/IFR conditions in freezing rain over northwestern SD will
continue through this morning. Elsewhere, mainly VFR conditions
expected for a short period through early afternoon, but then
MVFR/IFR conditions due to rain/snow will develop late in the
period and affect the entire area after 12/00z.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory until 11 AM MST this morning for SDZ002-
     013-014-032-078.
     Wind Advisory until 5 PM MST this afternoon for SDZ027-041.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...Wong
AVIATION...Dye