846
FXUS63 KUNR 091727
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1127 AM MDT Wed Jul 9 2025

.KEY MESSAGES...

-Isolated to scattered thunderstorms continue over the next
 couple days, some of which may be strong to severe today,
 especially this afternoon in western South Dakota

-Hot today, with moderating temps through the weekend behind a
 cold front

-Mainly dry this weekend with unsettled conds possible again next
 week

&&

.DISCUSSION...(Today Through Tuesday)
Issued at 123 AM MDT Wed Jul 9 2025

Mean WNW flow aloft will continue, supporting near daily impulses
through the region the next few days. A stronger system will
force a cold front through the region Thursday night, with things
cooling down Friday and mainly dry weather this weekend. Weak
impulse currently supporting elevated pos theta-e adv across
scentral SD this morning. Expect isold TS to continue there,
shifting east through early morning. A few stronger cells are
possible, supporting hail and gusty winds. Lee-side trough will
slowly push into the region today and will provide the focus for
sct SHRA and TS this afternoon, in addition to expected convection
over the Black Hills. Weakly capped environment with abundant ll
moisture will be in place ahead of the trough, with weak forcing
aloft providing the additional support needed to fire convection.
ML CAPE of 1500-3000 J/JG will be enough for isold strong to
severe storms when coupled with increasing shear as a jetlet
advects into the region later. Storms will shift east this
evening. However, another round of elevated pos theta-e adv will
support slight chances for TS overnight across much of the area,
although there would likely be banding in cells where the nose of
the strongest advection occurs. Another slug of monsoon moisture
will advect over the region Thurs ahead of a stronger impulse.
This combined with residual LL moisture will support another round
of sct-isold TS Thurs afternoon and evening, with the bulk of
convection shifting into central and eastern SD in the evening.
Breezy NW winds will develop behind the cold front Thur night with
cooling and drying ongoing. Residual moisture may force a few
showers/storms over the far SW Friday, but most places will
probably end up dry. Mainly sunny and dry this weekend, although
return flow may support convection by Sunday over the far west.
Unsettled flow then looks to return next week as a baroclinic zone
stalls near or over the region with sufficient moisture and fast
flow aloft.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Thursday)
Issued At 1126 AM MDT Wed Jul 9 2025

Generally VFR conditions are expected through the TAF period.
Isolated to scattered storms are expected this afternoon and
evening. Brief MVFR conditions may be possible in storms.


&&

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

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...Dye