547
FXUS63 KUNR 022259
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
459 PM MDT Thu Oct 2 2025

.KEY MESSAGES...

- Above normal temperatures and dry conditions continue through
  Friday.

- Elevated to critical fire weather conditions through Friday.

- Pattern change over the weekend toward cooler temperatures and
  increasing chances for precipitation.

&&

.DISCUSSION...(This Evening Through Thursday)
Issued at 141 PM MDT Thu Oct 2 2025

Current Water Vapor and upper air models show upper ridge over the
Great Lakes region flattening out, as the upper trough slides over
the west coast, with southwest flow over the forecast area.
Surface analysis shows a low over eastern North Dakota, while
surface high sits over MT/WY region. Winds currently are mainly
out of the south to southeast, with temperatures in the upper 70s
and 80s.

Upper ridge builds into the northern and central plains later
today into Friday, prompting an increase in temperatures. Some
record daily highs could be possible on Friday, with HREF
probabilities of 90 degrees or higher in the afternoon reaching
into the 60-95 percent range for much of the western SD plains.
Deep mixing will also allow for some breezy winds Friday
afternoon, with gusts 25 to 35 mph over some areas of the plains.

We`ll start to see a pattern shift Saturday, as upper trough digs
into the Rockies Saturday and over the northern plains by Sunday.
A shortwave and associated cold front is expected to move through
around this same time frame. Models show a 15-20 degree change,
with highs on Sunday only in the 50s to mid 60s. Better forcing
and moisture with this wave will bring a good chance for wetting
precipitation later Saturday into Sunday. LREF probabilities for
0.5" QPF or greater show a widespread signal of 50-70% chances
later Saturday into Sunday. The Black hills will see low
temperatures in the 30s Sunday morning, with some higher elevation
areas potentially seeing a transition to some light snow in the
coldest hours. Strong pressure rises behind the front will also
prompt gusty northwest winds that may require wind advisory
headlines.

This pattern looks to stick around at least through early next
week, with temperatures staying at or below normal, and perhaps a
few chances for precipitation. Models diverge greatly the middle
of next week, bringing some uncertainty to any local weather
impacts.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Friday Evening)
Issued At 457 PM MDT Thu Oct 2 2025

VFR conditions will continue through the forecast period. South-
southwesterly winds will increase after 15-17z Friday morning,
with gusts 20 to 30 knots expected across NE WY and the western SD
plains.

&&

.FIRE WEATHER...
Issued At 141 PM MDT Thu Oct 2 2025

Elevated fire weather conditions can be expected today mainly
across northeast WY and southwest SD. Although RH`s will drop to
around 15 to 20 percent, winds will be generally light today.
Warmer temperatures, deeper mixing, and breezy southwest winds are
expected Friday for much of the area. RH`s will fall to around 10
to 15 percent across parts of northeast WY and southwest SD in
the afternoon with breezy southwest winds developing (frequent
gusts over 25 mph likely). Given dry fuels and these concerns,
issued a Red Flag Warning for Friday afternoon for much of
northeast WY and southwest SD.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Red Flag Warning from noon to 7 PM MDT Friday for SDZ321-322-
     324>326-329-332.
WY...Red Flag Warning from noon to 7 PM MDT Friday for WYZ314>317.
&&

$$

DISCUSSION/KEY MESSAGES...Dye
AVIATION...SE
FIRE WEATHER...Dye