728
FXUS63 KUNR 220847
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
147 AM MST Sat Nov 22 2025

.KEY MESSAGES...

- Mild and dry today and Sunday.
- Colder air mass arrives Tuesday with light rain/snow possible.
- Cold persists through Thanksgiving into next weekend.

&&

.DISCUSSION...(Today Through Friday)
Issued at 146 AM MST Sat Nov 22 2025

Water vapor imagery shows multiple shortwave troughs embedded
within the northwest flow upstream of the forecast area. The first
initial wave is quickly shifting east into the Upper Midwest with
increased high level clouds across the forecast area. A second,
stronger wave, is pushing into eastern MT and is forecast to push
through ND later today. A surface trough will pivot through the
region as this wave shifts through, bringing gusty (25-35 mph)
northwest winds to the western SD plains this afternoon. Highs
will be in the 50s with cooler temperatures in the higher
elevations of the Black Hills and along the ND/SD border.

Warm air advection resumes overnight tonight into Sunday with dry
west-southwest flow aloft resulting in a mild and sunny day to end
the weekend; highs will be ~5-15F+ above normal Sunday afternoon.

Currently, a closed upper low is analyzed off the Baja Coast. This
low will eject into the Central/Southern Plains overnight Sunday
into Monday, clipping south-central SD. Light rain showers
possible for south-central SD early Monday morning. Another
shortwave is forecast to drop into the Northern Plains late Monday
with a strong cold front to follow. This front will arrive late
Monday night/early Tuesday with much colder air spilling into the
Northern Plains. As this system pushes through, light rain/snow
will transition to all snow through the day Tuesday, with
accumulations limited to the higher terrain of the northern and
Wyoming Black Hills (~35-40% probability of >1" snow per NBM
probs). Advisory level winds are possible behind the front Tuesday
across the western SD plains.

Ensembles and deterministic guidance both show decent agreement in
a deeper trough to impact the central US by next weekend, although
considerable track differences remain, limiting predictability in
the precipitation forecast. Will continue to monitor the snow
potential, although confidence is high that even colder air will
filter into the region next weekend with ~30% chance of sub-zero
temperatures Dec 1-2.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Saturday Night)
Issued At 926 PM MST Fri Nov 21 2025

VFR conditions are expected through the TAF period.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...SE
AVIATION...Wong