718
FXUS63 KUNR 241729
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1129 AM MDT Sun Aug 24 2025

.KEY MESSAGES...

- Mild temperatures continue through early next week (70s-80s).

- A few showers and storms possible across the Southern Hills and
  far southern areas through Wednesday (15-25%).

- More widespread shower and thunderstorm chances (30-40%) arrive
  for Thursday and Friday.

&&

.DISCUSSION...(Today Through Saturday)
Issued at 138 AM MDT Sun Aug 24 2025

Upper level analysis has high pressure over the Four Corners region
with a negatively tilted ridge extending northward into the Pacific
Northwest and a longwave trough extending down along the Mississippi
River Valley. At the surface, high pressure is building in from the
north as a few isolated showers/storms continue near the Nebraska
border.

For today, showers will end early this morning, leaving behind the
mid level clouds south of Interstate 90. The northeastern half of
the area will remain clear and dry. Temperatures will be mild and
winds light.

For tonight, expect a few isolated showers/storms to develop around
midnight close to the Nebraska border again due to warm air
advection, increasing low-level jet, moisture convergence and
elevated instability. Once again, these showers/storms will
dissipate/move southeastward just after sunrise.

The potential for isolated showers and storms will continue across
the southern portion of the forecast area Monday and Tuesday as the
upper ridge breaks down and pushes east in response to a developing
trof over the western CONUS.

The thermal ridge axis will be centered across the forecast area on
Wednesday, allowing 850 temps to warm to +20C to +23C corresponding
to highs well into the 80s. The ridge will flatten Thursday and
Friday, allowing active southwest flow to develop. With the return
of monsoonal moisture and shortwave energy ahead of the western
trof, expect unsettled conditions and higher chances for storms
across the entire area.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Monday)
Issued At 1120 AM MDT Sun Aug 24 2025

VFR conditions are expected through the TAF period. Some mid-level
cloud cover may brush near the TAF sites tonight; however,
confidence in this happening was low enough to omit from the TAF
with this issuance.

&&

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

$$

DISCUSSION/KEY MESSAGES...Smith
AVIATION...Cooley