257
FXUS63 KUNR 101718
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1118 AM MDT Fri Oct 10 2025

.KEY MESSAGES...

- Mild through Saturday with gusty southeasterly winds and
  limited precipitation chances
- Upper level trough and cold front Sunday will bring very windy
  northwesterly winds, colder weather, and some showers
- Unsettled weather next week

&&

.DISCUSSION...(Today Through Thursday)
Issued at 153 AM MDT Fri Oct 10 2025

07z surface analysis had high pressure over the Dakotas which has
pushed decaying cool front well south of the CWA. Water vapour
loop had upper ridge rebounding over MT/WY with some mid/high
clouds bubbling northeast from the Rockies. Mostly clear skies
over the CWA.

Today/Saturday, upper ridge shifts eastward as thermal ridge
builds back into the northern Plains by Saturday. Surface high
shifts east with decent pressure gradient behind it and 2-3mb/3hr
pressure falls across MT courtesy of warm air advection/lee trough
development. Result will be increasingly gusty southeast winds
during the day and moderate low level jet at night. Lower
tropospheric theta-e advection/limited buoyancy may support
isolated shra/TS late today/tonight mainly east of the Black
Hills. Temperatures will be near guidance.

Saturday night/Sunday, upper trough approaches as lead shortwave
zips into the northern Rockies. Double barrel cold front moves
through. First cold front arrives earlier Sunday and then a
reinforcing shot later Sunday as best QG-forcing/moisture stays
northwest of the CWA. PoPs still reasonable, but confidence in
meaningful QPF is rather low. Tight pressure gradient will support
very windy northwest winds, particularly with the second cold
front when 3-5mb/3hr pressure rises may occur. Have limited wind
gusts to 55mph given NBM probability of >55mph <40% in a limited
area over northwestern SD. Suspect wind headlines will be needed
as we watch wind gust trends unfold.

Next week will be unsettled as upper trough/cyclonic flow spins a
series of shortwaves from the Rockies into the Plains. Confidence
is low in timing/impact of each wave, but suspect we`ll see a
couple rounds of showers. Temperatures will be cold enough for a
bit of snow over the highest elevations, but impactful
accumulation unlikely at this point.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Saturday)
Issued At 1115 AM MDT Fri Oct 10 2025

VFR conditions will continue through the forecast period. Southeast
wind gusts of 25-40kt will be common. LLWS may develop east of
the Black Hills tonight where the surface winds quickly drop off.

&&

.FIRE WEATHER...
Issued At 153 AM MDT Fri Oct 10 2025

Gusty southeasterly winds today/Saturday become very windy
northwest Sunday. Minimum relative humidities will dip into the
20s for some, but should remain high enough to preclude Fire
Weather headlines.

&&

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

$$

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