155
FXUS63 KUNR 291144
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
544 AM MDT Tue Sep 29 2026

.KEY MESSAGES...

-Leftover clouds will decrease today from west to east, leading to
 sunny to mostly sunny skies this afternoon.

-Seasonal and mostly dry the rest of the week. Next chance for any
 passing rain is late Thursday into Thursday night.

&&

.UPDATE...
Issued at 947 PM MDT Mon Sep 28 2026

Thunderstorms continue to move across western SD at this hour. A
few storms in northwestern SD are on the stronger side and radar
analysis indicates they`re producing some small hail. With current
mesoanalysis depicting 500-1000 J/kg MU CAPE with marginal shear
over northwestern SD, these storms should remain subsevere as they
move east over the next few hours, though they may produce some
gusty winds, hail, and brief heavy rainfall.

Expecting warmer and drier days on tap for Tuesday and Wednesday
as heights rise in the wake of the upper wave and quasi-zonal
upper level flow establishes itself. Next chances for precip will
be on Thursday as a cool front pushes through the region.

&&

.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 12Z TAFS Through 12Z Wednesday Morning)
Issued At 534 AM MDT Tue Sep 29 2026

VFR conditions moved into the area overnight and will continue to
move into the area for the rest of today.

&&

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

$$

UPDATE...Wong
DISCUSSION...JC
AVIATION...GS