317 

FXUS63 KUNR 302328

AFDUNR



Area Forecast Discussion For Western SD and Northeastern WY

National Weather Service Rapid City SD

428 PM MST Tue Dec 30 2025



.KEY MESSAGES...



- Mild and dry conditions will persist through the weekend



&&



.DISCUSSION...(This Evening Through Tuesday)

Issued at 1236 PM MST Tue Dec 30 2025



20Z upper level analysis has a cutoff low off the southern 

California coast, broad ridge over the western CONUS, and a broad 

trof across the eastern CONUS. Fast northwest flow is in place 

across the Northern Plains, with mostly clear skies and high 

clouds streaming through at times. At the surface, broad high 

pressure is in place across much of the western United States, 

with the forecast area on the eastern periphery. Temperatures 

across the forecast area at 2pm are in the 40s to lower 50s, with 

breezy northwest winds across the SD plains.



Western upper ridge will remain nearly stationary through the end

of the week. Mild and dry conditions will persist for the next

several days, with breezy west to northwest winds at times.

Temperatures will range from the upper 30s in far northwest and

central SD areas, to the mid 50s further south and west. Weak

baroclinic zone will wiggle a little further west on Friday,

allowing the cooler 30s to cover more of the western SD plains, 

with 40s elsewhere.



As the western upper ridge shifts into the northern Rockies and

Plains for the weekend, the baroclinic zone wiggles back east, 

with widespread 40s and 50s expected across the area again.



Upper ridge stands pat over the central CONUS into early next

week, with dry and mild conditions continuing across the area.

Temperatures remain well above average into the middle of next

week.



&&



.AVIATION...(For the 00Z TAFS Through 00Z Wednesday Evening)

Issued At 428 PM MST Tue Dec 30 2025



Local IFR CIGS may develop over the far eastern reaches of the CWA

from KD07-KICR after 31/21z. Otherwise, expect VFR conditions

through the period.



&&



.UNR WATCHES/WARNINGS/ADVISORIES...

SD...None.

WY...None.

&&



$$



DISCUSSION/KEY MESSAGES...15

AVIATION...Helgeson