131
FXUS63 KUNR 021714
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1114 AM MDT Sat Aug 2 2025

.KEY MESSAGES...

-Unsettled conditions through the weekend with isolated to
 scattered showers/storms at times

-Warmer and drier next week

&&

.DISCUSSION...(Today Through Friday)
Issued at 146 AM MDT Sat Aug 2 2025

Semi-unsettled westerly flow will continue through this weekend
with chances for showers and thunderstorms in parts of the region.
Flow will amplify next week, with drier and warmer SW flow
becoming established, although weak passing waves will support
isolated TS chances at times in the area. Lee side trough will
shift east with warmer and drier conds today over the majority of
the FA, esp over northeast WY where dewpoints will fall in the 40s
and even a few 30s. East of the trough/dryline in western SD,
semi-humid conds will continue. Slow moving compact mcv/upper low
will shift into the eastern part of SD today, with a few lingering
morning showers possible toward central SD, possibly lingering
into early afternoon. Dry weather expected over the remainder of
the FA most of the day. However, the next impulse will shift into
the region late in the day, supporting chances for showers and
storms as convection fires on the high terrain of WY and shifts
east, possibly skirting the far SW in the late afternoon and early
evening. Another area of expected activity will be over eastern
MT, with storms developing there in the late afternoon/early
evening and possibly sagging into the FA this evening. Broad
brushed low pops over most of the FA this evening as the weak
impulse shifts east, with storms likely being driven by outflow
boundaries and local effects, making it difficult to pinpoint
exactly where storms will develop and propagate. Sufficient CAPE
will be in place, however deep layer shear will again be lacking.
Main threat with any stronger storms will be strong gusty winds
given deeper BL mixing expected today and appreciable downdraft
CAPE. Expect warmer highs today with mainly 80s expected. Any
lingering storms will shift east and wane overnight. Sunday is
trending drier with shortwave ridging expected. The best chance
for any storms will be over the Black Hills given conditional
instability in place with weak CIN. Hence, have the highest pops
there and on the adjacent Plains to the east. Outside of the
Hills, there really isn`t a strong signal for convective forcing
other than a sfc trough stalled over NW SD. Hence have cut pops
and limited to 20 most other places. Lack of deep layer shear, and
marginal CAPE will support a low threat for severe weather, with
gusty winds being the main threat. Digging western CONUS trough
early next week will support warmer temps over the Northern Plains
and a drying trend, with the bulk of TS coverage expected to be
more isolated. Expect some 90s to return Monday and Tues, with TS
chances being driven by any passing impulses.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Sunday)
Issued At 1112 AM MDT Sat Aug 2 2025

Some isold storms are possible aft 00z across the Black Hills
region as well as across south central SD. This should last
through 05Z. Otherwise VFR conditions are expected through the
valid forecast period.

&&

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

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...Hintz