371
FXUS63 KUNR 290047
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
647 PM MDT Mon Sep 28 2026

.KEY MESSAGES...

-Scattered showers and storms this afternoon and evening,
 shifting southeast overnight

-Seasonal and mainly dry the rest of the week

&&

.DISCUSSION...(This Afternoon Through Sunday)
Issued at 1015 AM MDT Mon Sep 28 2026

Deep moisture will shift east today via a northern stream
shortwave and associated sfc trough. This will transition the
region into WNW flow aloft and allow for occasional cool fronts
later in the week. Another monsoon wave will push NE into the
region this afternoon and interact with a sfc trough dropping into
the region. This will force showers and storms across the FA with
the best chances across NW SD late this afternoon and scentral SD
overnight. A few stronger storms are possible this afternoon
across NW SD where increased flow aloft may allow storms to
organize for a bit, supporting gusty winds and small hail. Things
will dry out NW-SE into Tue, with lingering shower chances reaming
across far eastern scentral SD through Tue morning. Seasonal and
dry Tue and Wed. Cool fronts will knock down temps Thur, and again
this weekend, with highs in the 60s behind these systems. Some
light rain may develop with the NW flow impulses if enough forcing
and moisture is realized, but these systems will be mainly dry.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Tuesday Evening)
Issued At 646 PM MDT Mon Sep 28 2026

Scattered thunderstorms in NW SD could cause locally strong winds
and heavy rainfall and may reduce conditions to being MVFR/IFR.
Conditions will improve starting in the west and moving east
through the night. However, south central SD will see showers
linger in the area which may result in IFR for CIGS/VSBY. VFR
conditions are expected in NE WY and will be widespread across
western SD by Tuesday morning.

&&

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

$$

DISCUSSION...JC
AVIATION...Ivory