670
FXUS63 KUNR 041953
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
153 PM MDT Sat Oct 4 2025

.KEY MESSAGES...

- Widespread rain and colder temperatures today into Sunday.

- Warming trend early next week, with drier conditions.


&&

.DISCUSSION...(This Evening Through Saturday)
Issued at 104 PM MDT Sat Oct 4 2025

Current Water Vapor and upper air models show upper trough from
western MT down into UT this afternoon as broad upper ridge sits
over the Great Lakes region. Surface analysis shows an initial
frontal boundary that has moved through the forecast area today
currently stretching from northeastern SD down into western NE,
and a stronger cold front that will impact the area later
currently over MT into western ND. Radar currently shows
scattered showers over northeastern WY and parts of western SD
this afternoon behind the initial front. Winds are generally out
of the north to northeast with gusts 20 to 25 mph, and
temperatures sit in the mid 60s to mid 70s for most places, while
south central SD sits in the low 80s.

As the upper trough moves towards the northern/central plains
later today, expect an increase in showers and maybe a few
embedded thunderstorms this afternoon and evening. Limited CAPE
given the cloud coverage early in the day, but LLJ shifting over
the area will help increase TS potential. The higher QPF amounts
are expected this evening through Sunday morning where the better
moisture and lift will be over the forecast area. HREF
probabilities of 0.5" precip over the next 24 hours shows a strong
signal from northeastern WY into northern SD, as well as the
Black Hills. Gusty northwest winds are expected behind the 2nd
front on Sunday. GFS/NAM models have dialed back a bit on the
pressure changes behind the front now, more in the 3-5 mb/3hr
range late Sunday morning into the afternoon. Still could see a
short timeframe just behind the front of 45-50 mph gusts as it`s
going through. Expect much colder temperatures for Sunday and
Monday behind the front, with highs in the 40s over the Black
Hills, and 50s elsewhere. A secondary upper trough may support
another round of light rain or snow across mainly the southwest
third Sunday night into Monday morning.

Lingering precipitation will taper off early Monday, and upper
trough slides east of the Region later Monday into Tuesday.
Meanwhile broad upper ridge builds over the western CONUS Tuesday,
sparking a warming trend towards mid-week and drier conditions.
The Euro and GFS both point to a potential shortwave crossing the
northern plains later next week, though differ timing and strength.
Both models show scant moisture with this disturbance, however it
is still pretty far out. Will monitor trends to see the degree of
local effects.



&&

.AVIATION...(For the 18Z TAFS Through 18Z Sunday)
Issued At 1130 AM MDT Sat Oct 4 2025

A storm system will bring showers and isolated thunderstorms as
well as MVFR/IFR conditions through the rest of the forecast
period. The lowest cigs and heaviest precipitation will be found
from northeast WY into NW SD tonight. Winds will increase from the
northwest after 06Z, with gusts over 35 knots as a cold front
moves from northwest to southeast across the area Sunday morning.

&&

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

$$

DISCUSSION/KEY MESSAGES...Dye
AVIATION...Smith