625
FXUS63 KUNR 061129
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
529 AM MDT Sun Sep 6 2026

.KEY MESSAGES...

- Above average temperatures remain in the forecast. The hottest
  day will be today with highs in the mid to upper 90s with 80s
  and 90s expected Sunday and Monday.

- Elevated fire weather conditions are expected through the
  weekend.

- Isolated to scattered thunderstorms are expected through
  Sunday, focusing on this evening and Sunday afternoon/evening

&&

.UPDATE...
Issued at 1032 PM MDT Sat Sep 5 2026

Storms have moved out of the region, though elevated instability
remains across much of the region with recent mesoanalysis depicting
1000-2000 J/kg MUCAPE over much of the western SD plains. With a
lack of forcing, we likely won`t see much, if any, convection
overnight. Still looking like we`ll see chances for storms tomorrow
afternoon and evening as a shortwave grazes the region. Have made no
major changes to the forecast aside from some minor adjustments to
PoPs overnight into tomorrow afternoon based off of latest CAMs.

&&

.DISCUSSION...(This Afternoon Through Friday)
Issued at 1139 AM MDT Sat Sep 5 2026

For the rest of today, isolated storms are drifting northwards.
But with weak flow and weak large scale forcing, storm coverage
will be limited, which will help lower the overall severe risk.
Enough instability exists that severe wind gusts and severe hail
are possible. For now, thinking is these storms drifting
northwards will travel east to northeast this afternoon, tracking
through the SD plains through tonight. Today`s afternoon temps
will be much above normal, in the 90s to near 100. Overnight temps
will cool to the 60s for most of the area, little cooler in the
Black Hills.

Around round of passing storms is likely tomorrow/Sunday. An
upper level trough, currently sitting and spinning over the
pacific northwest, will swing over Montana. This trough will
likely be the main weather maker for the area for a couple days.
As it kicks east and north, thunderstorms will be likely ahead of
the trough. And this kind of pattern has had a history of
producing severe weather. The SPC has placed a marginal severe
risk out for Sunday over the Black Hills and to the north and
machine learning severe weather models are hinting at the risk of
severe weather centered over the CWA Sunday into Monday. For now,
thunderstorms will likely get going around noon over the Black
Hills and those will track northward. Then late Sunday into Sunday
night, a reinforcing round of moisture and storms will drift
northward through the area. Now is a good time to be sure of
having a way of being informed of severe weather in your area.

For next week, very low chances for precip lingers in the
forecast with slightly cooler weather Tuesday and Wednesday,
before the upper 80s to 90s return later in the week.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Monday Morning)
Issued At 529 AM MDT Sun Sep 6 2026

Isolated to scattered thunderstorms will develop this
afternoon/evening with local MVFR conditions. Have left storms out
of the terminals for now given low confidence in location of
convective initiation Sunday afternoon. Outside of thunderstorms,
VFR conditions are expected through the period.

&&

.FIRE WEATHER...
Issued At 1139 AM MDT Sat Sep 5 2026

Warm and dry conditions are still found around the area today,
especially over northeastern WY and parts of western SD but the
winds aren`t as strong as they have been. So elevated fire
weather conditions are expected today.

Temperatures will be hot again tomorrow and Sunday with highs
well into the 90s to near 100 degrees. Very low humidity is also
expected to continue, dropping to near 15 to 20 percent in the
afternoons across northeastern WY and portions of far western SD.
The winds will continue to be not as strong, so at this time, Red
Flag Warning thresholds are not expected to be met so a Red Flag
Warning extension is not expected at this time.

&&

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

$$

UPDATE...Wong
DISCUSSION...GS
AVIATION...Dye
FIRE WEATHER...GS