904
FXUS63 KUNR 052326
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
526 PM MDT Sat Sep 5 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

&&

.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 00Z TAFS Through 00Z Sunday Evening)
Issued At 521 PM MDT Sat Sep 5 2026

Isolated/scattered thunderstorms will continue this evening over
western SD, waning overnight as they move northeast. Local MVFR
conditions will occur with the strongest storms as well as gusty,
erratic winds and perhaps some hail. KRAP will be affected
through 06/01z. Additional storms will develop 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.
&&

$$

DISCUSSION...GS
AVIATION...Helgeson
FIRE WEATHER...GS