345
FXUS63 KUNR 301951
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
151 PM MDT Sat Aug 30 2025

.KEY MESSAGES...

- Chances of showers and an isolated storm through Sunday
  afternoon, drier Monday.

- Cool Sunday, warmer Monday, but still seasonal.

- Cold front Tuesday night brings cooler temperatures for
  Wednesday.

&&

.DISCUSSION...(This Evening Through Saturday)
Issued at 149 PM MDT Sat Aug 30 2025

Latest analysis has a stacked low over central South Dakota with
showers and a few thunderstorms rotating around the low across the
northern and eastern portions of the forecast area. This system will
be the main forecast driver for the short term period, resulting in
chances for showers and storms through Sunday afternoon.

For tonight, wrap-around moisture will continue, with the highest
QPF east of a line from Buffalo to Union Center to Philip. Some
of this area has already received 2 to 4 inches of rain. Reports
from the area have said the water is mostly soaking into the
ground, with a little bit of standing water in the ditches and
draws. With expected breaks and lulls in the intensity, the
vegetation in combination with ground cracks and dry draws/creeks,
should keep flooding concerns at bay.

For Sunday, the low will drop southeastward into northeast Nebraska,
shifting the wrap around showers to the southeast and the heaviest
precipitation axis over south central South Dakota, before exiting
Sunday night. HREF are still giving 50-70% probs of greater than an
inch of precipitation just east of a line from Bison to Philip and
White River to Mission.

As this low exits the area, mainly dry conditions are expected as
the upper ridge builds over the Rockies and a strong upper low moves
eastward into Ontario, resulting in northwest flow over the forecast
area. A cold front drops down Tuesday night, bringing a chance for
showers/storms late Tuesday into Wednesday. Behind the front,
ensembles indicate 850 temps will drop by 10C, resulting in a 15F to
20F drop in high temperatures on Wednesday.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Sunday)
Issued At 1113 AM MDT Sat Aug 30 2025

MVFR conditions expected this afternoon at KRAP with brief IFR
conditions possible in heavier shower or storms this afternoon.
Chances are lower of seeing showers and storms at KGCC, but kept a
PROB30 -TSRA group as a few storms may approach the TAF site
during peak heating. Overnight, light winds are expected with
lingering low level moisture over the plains of western Sound
Dakota, which may allow for fog/low stratus formation.

&&

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

$$

DISCUSSION/KEY MESSAGES...Smith
AVIATION...Cooley