195
FXUS63 KUNR 112338
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
538 PM MDT Sat Oct 11 2025

.KEY MESSAGES...

- Gusty downslope winds for the northern and eastern slopes of
  the Black Hills overnight tonight
- Upper level trough and cold front Sunday will bring very windy
  northwesterly winds, colder weather, and PoPs in the northwest
- Freezing temperatures likely most areas Monday morning

&&

.DISCUSSION...(This Evening Through Saturday)
Issued at 128 PM MDT Sat Oct 11 2025

19Z upper level analysis has high amplitude ridge over the central
CONUS, and deep trof across the far western CONUS. Nicely defined
upper shortwave is currently lifting north in fast southwest flow
across Wyoming, bringing some light to moderate rain in places,
along with a large cloud shield. Some light rain is just now
moving into far southwestern portions of the area. At the
surface, low pressure is located across eastern Montana, with a
warm frontal boundary across western portions of the forecast
area. The cold front is well west in central Montana.

Upper trof will slowly move across the Northern Rockies tonight,
as the surface low deepens across eastern Montana. Forecast area
will be in the warm sector of this system overnight, with mild
temperatures expected.

As the surface low and cold front inch closer to the area, strong
southwesterly winds are likely across the northern and eastern
Black Hills foothills with gusts of 35-45 mph likely. Then shortly
before sunrise Sunday, the main cold front will enter the area
with winds switching to the northwest. Wind gusts to 50 mph will
be possible as the front crosses the forecast area early Sunday
morning, with winds diminishing a bit by late morning. By
afternoon, 2-4mb/3hr pressure rises, along with best mixing will
allow westerly winds to pick back up to 45-55 mph gusts across
northwest SD - finally beginning to diminish by early evening. A
wind advisory has been issued from 3am-7pm Sunday from the
northern and eastern foothills of the Black Hills, across most of
northwestern SD.

In addition to the winds on Sunday, the upper trof axis will
swing into the Northern Plains, producing some light precipitation
across northeastern Wyoming and the Black Hills. A few snowflakes
are possible across the higher elevations. Precip dries out
quickly Sunday afternoon as the upper trof lifts into Canada. With
the frontal passage, a wide range of temperatures will be found
across the area, with highs around 50 across northeast WY, to the
70s across far south central SD.

Weak ridging redevelops over the area Sunday night into early next
week. Surface high pressure slides into the area late Sunday night
with skies clearing behind the exiting system. Surface winds will
likely go light by early Monday morning, allowing temperatures to
plummet to near or slightly below freezing. Some frost/freeze
headlines will likely be needed early Monday morning.

Upper ridge holds fast across the central CONUS as a deep closed
low settles south along the northern California coast.
Temperatures will slowly moderate through the first part of next
week, warming back above average for mid to late week. A weak
shortwave lifts across the area early in the week with only small
chances for some rain showers. Better shortwave energy looks to
lift across the area later in the week.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Sunday Evening)
Issued At 535 PM MDT Sat Oct 11 2025

A cold front will move through the region between 06Z and 12Z.
Gusty northwest winds, up to 35kts, will be found behind this
cold front. Additionally, a stratus deck accompanying the cold
front could create localized MVFR conditions.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from 3 AM to 7 PM MDT Sunday for SDZ001-002-
     012>014-025-072-073-078.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...15
AVIATION...Smith