867
FXUS63 KUNR 101116
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
516 AM MDT Sun Aug 10 2025

.KEY MESSAGES...

- Areas smoke/haze through Monday, especially for western SD
- Seasonally warm/hot temperatures expected next week with
  elevated fire weather conditions developing

&&

.DISCUSSION...(Today Through Saturday)
Issued at 131 AM MDT Sun Aug 10 2025

07z surface analysis had weak high over the CWA. Smoke/haze is
likely filtering into western SD per extrapolation of last
evening`s satellite loops/HRRR smoke guidance. Water vapour loop
had upper low over central MB with trough into the southern
Rockies.

Today/tonight, upper trough shifts east as 100kt jet on back side
slides into the plains. Weak lift over the CWA may assist limited
buoyancy/shear and produce some thunderstorms this
afternoon/early evening from the Black Hills southward.
Temperatures will be tempered by forecast smoke a skosh.

Monday, northwest flow aloft becomes well-established as upper
trough shifts northeast into Hudson Bay. Weak wave looks to drop a
weak cool front through the area during peak insolation. Moisture
will be limited, but a few CAMs sprinkle northwest SD with
isolated convection. If smoke shifts east as forecast,
temperatures should be near guidance.

Tuesday will slightly cooler on the western SD plains behind the
cool front, but then southwest flow aloft develops for
Wednesday/Thursday allowing thermal ridge to expand into the
northern plains. Sharp warm-up per ensemble guidance with 90s
common for MaxT and perhaps a few 100F readings as ground dries
out. A slightly more active pattern develops by Friday into next
weekend as weak shortwaves rotate around upper ridge in place over
the south-central CONUS. Temperature spreads expand, so
confidence decreases with regard to warm vs hot MaxTs.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Monday Morning)
Issued At 513 AM MDT Sun Aug 10 2025

Local MVFR VSBYS due to wildfire smoke may affect northwestern SD
through the forecast period. Isolated thunderstorms are possible
this afternoon/early evening from the Black Hills southward.

&&

.FIRE WEATHER...
Issued At 131 AM MDT Sun Aug 10 2025

Drier weather expected through Thursday with hot temperatures
returning for Wednesday/Thursday along with minimum afternoon
relative humidities in the teens for northeastern WY/southwestern
SD. Wind speeds may be sufficient for the development of elevated
fire weather conditions, particularly in areas where seasonal
fuels are starting to dry out significantly.

&&

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

$$

DISCUSSION/KEY MESSAGES...Helgeson
AVIATION...Helgeson
FIRE WEATHER...Helgeson