772
FXUS63 KUNR 112017
AFDUNR

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

.KEY MESSAGES...

-Strong cold front will shift into the region tonight with some
 light snow expected, mainly across the western third

-Cold and snowy Friday into Sat with snow accums expected,
 heaviest across NW SD Friday night

-Warm and dry the first half of next week

&&

.DISCUSSION...(This Evening Through Thursday)
Issued at 113 PM MST Thu Dec 11 2025

Active northern stream will continue to bring large swings in
temps along with precip chances through the end of the week.
Massive western CONUS ridge has directed another clipper system
along the top of the ridge. First cold front has settled south
into western SD with mainly 30s behind it and 50s-60s ahead to
the south. Lingering WAA precip cross NW SD is expected to taper
off this afternoon. CAA will ramp up overnight as NW winds
increase and the secondary arctic front drops into the region.
Some light precip will develop over the western third this
evening. Precip may start as rain first then quickly switch to
snow. An inch or 2 of accums will be possible across northeast WY
and the northern Black Hills. Baroclinic zone will then stall
over the region with several weak impulses agitating the flow and
supporting rounds of light snow. Accums will range form 1 to 2
inches in the SW half to third with 3 to 6 inches across the NE
half, heaviest across far NW SD. This prolonged period of FGEN is
expected to ensue sometime Friday morning and spread southeast
over the region, intensifying Friday night when the strong lift is
expected. Will defer headlines to the mid shift to allow fine
tuning of timing and amounts. In addition, some upslope fog will
also be possible later Friday into Sat. Expect much colder temps
with readings below zero across NW SD Sat morning and Sunday
morning, supporting wind chills 15 to 25 below there. The cold
spell will be short lived though. Upper ridge begins to shift east
Sunday with things quickly warming back up next week, along with
breezy conds as the nearby active northern stream supports
traversing impulses. The warm up will be quite strong Sun with
northeast WY and the higher elevations of the Black Hills expected
to see highs back in the 50s. The warm air will spread east on
the Plains Sunday, but will hinge on the strength of the wind,
with stronger wind allowing for better mixing and warmer temps.
Expect warm and dry conds into Wed at which time a stronger
clipper system will support a cold front into the region along
with chances for rain and snow.

&&

.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 2 PM MST this afternoon for SDZ014-
     032.
     Wind Advisory until 5 PM MST this afternoon for SDZ027-041.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...Dye