FXUS63 KUNR 121924

AFDUNR



Area Forecast Discussion For Western SD and Northeastern WY

National Weather Service Rapid City SD

1224 PM MST Fri Dec 12 2025



.KEY MESSAGES...



-Cold tonight with snow accums mainly across NW SD



-Rapid warm up Sunday with temps in the 60s in parts of the Black

 Hills and adjacent foothills



-Warm and dry the first half of next week with active weather and

 fluctuating temps after



&&



.DISCUSSION...(This Evening Through Friday)

Issued at 1223 PM MST Fri Dec 12 2025



Massive western CONUS ridge will drive the weather in the period 

as the active northern stream continues to alter its northern 

extent. Arctic front stalled over the region today, with rounds of

FGEN snow continuing. Another impulse is will shift the main FGEN

area back north with weak WAA aloft. This will support a round of

light to moderate snow across northwest into central SD tonight 

into Sat morning. Still expect low end adv snow there, with 

perhaps a slight downtrend in amounts compared to previous model 

runs. Expect cold temps tonight with lows below zero across NW SD,

warmer to the southwest. Frontal boundary will shift back south 

Sat, as weak CAA ensues behind the impulse. Some lingering clouds 

and flurries will be possible across the SW half Sat afternoon. 

Temps will drop off Sat night most places, esp the SD Plains where

subzero temps can be expected. However, WAA will ensue Sat night 

across western areas with temps starting to rise, esp in the BH. 

WAA will ramp up Sun as breezy SW winds develop across northeast 

WY and the BH, and foothills by afternoon. H85 temps are progged 

to warm to 20C by afternoon, which will support aggressive 

warming, esp in the BH and foothills where 60s are forecast for 

highs. Warm air will spread east with mild and dry weather 

expected through mid week. However, the active northern stream 

will force the frontal boundary back south later in the week, with

a roller coaster setup ensuing as several stronger shortwaves 

progress through semi-westerly flow. 



&&



.AVIATION...(For the 18Z TAFS Through 18Z Saturday)

Issued At 1024 AM MST Fri Dec 12 2025



Widespread MVFR/IFR conditions and -SN will continue across the

forecast area through today into tonight. Transient LIFR 

conditions are possible in heavier bands of snow through the day 

today.



&&



.UNR WATCHES/WARNINGS/ADVISORIES...

SD...Winter Weather Advisory from 5 PM this afternoon to 8 AM MST 

     Saturday for SDZ001-002-013-014-032-078.

WY...None.

&&



$$



DISCUSSION/KEY MESSAGES...JC

AVIATION...Dye