084 
FXUS63 KUNR 232247
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
347 PM MST Tue Dec 23 2025

.KEY MESSAGES...

- Breezy, mainly dry, and unseasonably warm this week.

- Record to near-record high temperatures on Christmas Day.

- Chance of snow and much cooler, but seasonal, this weekend.

&&

.DISCUSSION...(This Evening Through Tuesday)
Issued at 1236 PM MST Tue Dec 23 2025

20Z upper level analysis has large ridge across the central CONUS,
with mainly high cloudiness streaming across the Northern Rockies
and Northern Plains. At the surface, high pressure resides across
south central Canada into the Northern Plains, with a weak surface
low and stationary boundary from southeast Montana into eastern
Wyoming. Cool southeast boundary layer flow is present across much
of western SD, with warmer southwest flow across northeast WY into
far southwest SD. Temperatures across the forecast area at 1 pm
range from the 30s across far northern SD, to around 60 across
northeast WY and far southwest SD.

Central CONUS upper level ridge remains fairly stationary for the
remainder of the week, with dry conditions and much above average
temperatures expected. Weak surface boundary will waver across the
forecast area during this time period. North of this boundary
across northwestern SD, temps will remain near to slightly above
average through Friday. But south of the boundary, southerly to
southwesterly flow will persist, with temperatures well above
average. Several temperature records are likely to fall over the
next 3 days.

For Wednesday, high temps will be in the 60s from northeast WY
through south central SD, with low 70s possible along the SD-NE
border. 

On Thursday, the boundary shifts just a little further north, with
60s expected across much of the area, except far northwestern SD.

For Friday, slightly cooler air moves into the area, with temps
mainly in the 50s to mid 60s expected.

Upper ridge finally shifts east for the weekend, as a strong upper
trof crosses the Northern Rockies. Temperatures will fall back to
more seasonal readings on Saturday, with some light snow possible
across northeast WY and the Black Hills area, with little 
accumulation expected. Sunday will be the coldest day, with high 
temperatures remaining in the teens and 20s.

Upper ridge moves into the western CONUS early next week, with the
Northern Plains remaining under fast northwest flow. Temperatures
will moderate from the chilly temps over the weekend, with mainly
dry conditions continuing.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Wednesday Evening)
Issued At 347 PM MST Tue Dec 23 2025

VFR conditions to continue through the valid forecast period. 

&&

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

$$

DISCUSSION/KEY MESSAGES...15
AVIATION...Wong