Osage, Wyoming Weather Forecast Discussion

922
FXUS63 KUNR 111922
AFDUNR
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
122 PM MDT Thu Sep 11 2025
.KEY MESSAGES...
-Seasonally warm through Friday
-Isolated showers and thunderstorms through Friday with better
 coverage of showers this weekend most places
-Cooler after Monday next week
&&
.DISCUSSION...(This Evening Through Thursday)
Issued at 121 PM MDT Thu Sep 11 2025
Mean western CONUS trough continues to support semi-unsettled
weather across much of the Northern Plains and Rockies. This
system will continue to slowly shift east the next two days, with
better forcing shifting east by this weekend. This will support
increasingly unsettled weather in the Northern Plains. Weak
impulses will continue to shift northeast into the region ahead
the upper trough and support daily isolated shower/TS chances
through Friday. Gusty winds will be the main impact from any
stronger cells given plenty of low level dry air in place off the
sfc. Upper trough will shift east by this weekend with the main
batch of LSA and forcing spreading over the region. The the best
overlap of forcing and moisture will be well north of the FA.
However, the NAM and Canadian support higher precip totals over
the FA, likely due to convective contamination. However, most
other models generally keep the higher precip numbers north and
east of most of the area, which makes the most sense given the
best progged overlap of moisture and lift. Hence, will keep the
higher pops toward NW SD, with any rain over the southern 2/3 of
the FA expected to be convective and scattered. Cooler weather can
be expected this weekend with all the moisture and clouds around,
but there is really is not much of any CAA with this system.
Things dry out for the first part of next week, with warmer temps
Monday, but another upper trough moves into the region later in
the week, supporting additional rain chances as well as a cooler
temps. However, confidence in the track, strength, and resultant
precip chances remain very low attm given progged semi-blocked
flow, which typically leads to high forecast model uncertainty.
&&
.AVIATION...(For the 18Z TAFS Through 18Z Friday)
Issued At 1147 AM MDT Thu Sep 11 2025
Mainly VFR conditions are expected today into tonight. Isolated to
scattered thunderstorms will be possible across most of the area
this afternoon into tonight, with brief MVFR conditions in the
vicinity of stronger storms. Best chances for storms in and around
KRAP and KGCC will be from 22Z through 03Z.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION/KEY MESSAGES...JC
AVIATION...Dye

NWS UNR Office Area Forecast Discussion