850
FXUS63 KUNR 222324
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
524 PM MDT Fri Aug 22 2025

.KEY MESSAGES...

- Isolated thunderstorms possible tonight.

- Mild temperatures and with mostly dry conditions this weekend
  and into next week.

&&

.DISCUSSION...(This Evening Through Friday)
Issued at 1256 PM MDT Fri Aug 22 2025

Water vapor imagery shows the low across south central Canada
continuing to push of to the east with the broad trough axis
draped across the northern Plains. This trough axis has pushed
some drier air into the region today and has pushed the bulk of
the deeper moisture south into Nebraska. Residual moisture is
still pooled within the Black Hills as evident by an expansive
cumulus field that is developing this afternoon over the Black
Hills. Radar and VIS satellite show a few convective towers trying
to initiate and this trend will continue into the evening hours
with the possible of some isolated thunderstorms developing.

Storms that do develop will primarily stick to the terrain as
upper level forcing is quite weak with the exiting trough to the
east and a building ridge and increasing heights progged to come
into the region from the west, so any ongoing convection tonight
should come to an end quickly.

The aforementioned ridge axis builds across the southern Rockies
and per model guidance looks to be the main weather driver this
weekend and into much of next week. Persistent northwest flow will
usher in both cooler and drier air into the region allowing for
temperatures to drop to seasonal normals. A few models have some
weak disturbances coming through the NW flow that could initiate
some precipitation chances but with the drier air working its way
into the region the forecast will only advertise isolated, low end
(<20%) PoP chances throughout the week.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Saturday Evening)
Issued At 524 PM MDT Fri Aug 22 2025

VFR conditions will prevail at both TAF sites next 24hrs. Broken
mid clouds will prevail at both sites this evening and then
dissipate, leaving scattered cirrus over the sites remainder of
the night and into tomorrow morning. However, more broken AC
around 10kft will develop over the sites for late tomorrow morning
and continue into the afternoon. Winds at RAP will be northerly
until tomorrow morning and then become variable. Winds at GCC will
be northeasterly this evening, then become variable late
tonight...then switch to southeast tomorrow.

&&

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

$$

DISCUSSION/KEY MESSAGES...Woodward
AVIATION...Auten