466
FXUS63 KUNR 210455
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
955 PM MST Thu Nov 20 2025

.KEY MESSAGES...

-Seasonally mild and dry through the weekend

-Turning colder next week with some light snow possible

&&

.DISCUSSION...(This Evening Through Thursday)
Issued at 117 PM MST Thu Nov 20 2025

Mild Pac flow will continue into early next week as split flow
persists. Sfc front has stalled over the SW third. This supported
an area of low clouds and fog this morning with a large portion
of the fog and clouds having since burned off. The same area
across the SW third to half will likely see low clouds and patchy
fog once again tonight as LL moisture will remain in place with
ESE upslope flow. WAA will ensue overnight into Fri allowing for
mild conds most areas Fri, with mild conds most places persisting
through the weekend as zonal Pac flow continues over the northern
CONUS Rockies. Any morning clouds and fog will dissipate Fri
morning as dry air mixes down from aloft. Expect highs mainly in
the 50s and 60s through Monday, with some 40s over northeast areas
Friday. Pattern change will ensue next week as a large ridge of
high pressure in the north Pac dislodges a CP airmass into the
northern CONUS. This will ensue via a stronger cold front Mon
night into Tue, with breezy NW winds expected Tue. Some light snow
will be possible Tue into Wed across the western third, mainly
northeast WY and the northern BH. Additional precip chances later
in the week will depend on where the frontal boundary sets up next
week as impulses ride SE along the baroclinic zone.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Friday Night)
Issued At 954 PM MST Thu Nov 20 2025

Low stratus/fog and associated areas of MVFR/IFR/LCL LIFR
conditions will continue to overspread much of western SD into
northeastern WY. Conditions will slowly improve late Friday
morning.

&&

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

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...Wong