446
FXUS63 KUNR 051120
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
520 AM MDT Sun Oct 5 2025

.KEY MESSAGES...

-Much cooler with showers today

-Chance of rain (high elevation snow) over the southwest third
 tonight

-Frost possible in portions of the region the next two nights

-Gradual warming trend after Monday with dry weather

&&

.DISCUSSION...(Today Through Saturday)
Issued at 106 AM MDT Sun Oct 5 2025

Mean upper trough over the central NOAM will support much cooler
conds the next 2 days, with lingering showers today. Main batch of
lift and associated rain has shifted into ND, with a lingering
deformation zone across the NW third of the area. Some fog was
also observed along the northern foothills where NE upslope flow
has developed. Trowel will shift east and dissipate through
morning as the main area of forcing exits the region. This will
result in the best chances for rain this morning. A period of
breezy NW winds can be expected this morning as the main cold
front moves through the area. A few gusts over 40 mph can be
expected on the western SD Plains this morning, with speeds slowly
coming down through the day. Otherwise, scattered showers will be
possible this afternoon per diurnal heating. Things will dry out
this evening most places. However, a secondary upper trough on the
back of the mean upper trough may support another round of light
rain or high elevation snow across the southwest third tonight
into Monday morning. The best forcing and better moisture will
remain southwest of the FA with dry air beginning to push in from
the north. Hence, not expecting much QPF if precip materializes in
the FA. Profiles will certainly be cold enough for snow across
the higher elevations of the BH as well as portions of the WY
Plains. Any accums would be very light. Where skies clear and
winds drop off, areas of frost will be possible, mainly across NW
SD tonight and far western SD and northeast WY Monday night. Upper
trough will shift east out of the area by Tues with upper ridging
mid week. This will allow for a warming trend and dry weather. An
upper trough looks to top the ridge and support a backdoor cool
front Thurs-Fri. However, the degree of height falls and local
effects remains at low confidence per continued large model
spreads. Growing indications for unsettled weather later next
weekend or early next week as a deep upper trough moves into the
Rockies, with low confidence in any details wrt this feature attm.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Monday Morning)
Issued At 517 AM MDT Sun Oct 5 2025

A storm system will continue to bring rain along with MVFR/IFR
conditions through the morning hours. Drier air will move in later
this afternoon and evening with conditions trending VFR most
areas. However, another system may bring some MVFR-IFR conds
across northeast WY into SW SD later tonight into Monday
morning. Winds this morning will increase from the northwest with
gusts over 35 knots as a cold front crosses the area.

&&

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

$$

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