417
FXUS63 KUNR 011714
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1114 AM MDT Mon Jul 1 2024

.KEY MESSAGES...

-A few severe storms are possible today from southwest to central
 SD

-Unsettled pattern will bring near daily chances for
 showers/storms through Thursday

-Temps will be around normal, or on the cool side of normal most
 of this week, coolest Thur

-Warmer and drier this weekend

&&

.DISCUSSION...(Today Through Sunday)
Issued at 120 AM MDT Mon Jul 1 2024

Fairly active northern stream will prevail this week with near
daily chances for showers and storms through Thur as a frontal
boundary wavers over the region and mean troughing prevails
through mid week. Sfc cool front will slide into the region today
as another stronger impulse ejects out of the Rockies. This
impulse will support a good deal of LSA and strong forcing,
allowing TS to develop in the afternoon over far western SD.
Storms should grow upscale into isolated supercells and convective
line segments, supporting large hail and damaging winds given
bulk shear of 35-45 knots. CAPE will be somewhat limited in
western SD topping out AOA 1000 J/kg, however dynamic forcing
should make up for the lack of sig CAPE there. Deeper moisture and
better CAPE will reside over central SD where storms will likely
intensify as they shift east in the late afternoon. Further west
across WY, plenty of shear will be in place for very isolated
supercells, but given conditional nature of convection and limited
CAPE, any severe threat will be very isolated. Temps will top out
in the lower 90s from SW to central SD where skies clear out
ahead of the cool front, with 70s and 80s elsewhere. Sfc front
will settle south of the region tonight. Another impulse will
support shower development along and north of the front across the
SW third, with any activity being sct-isold. Diurnal heating with
a conditionally unstable env may support shra/ts in the afternoon
Tues. Otherwise, it will be slightly cooler with highs in the 70s
and 80s. Deeper upper trough will settle into the Northern Plains
Wed, supporting more chances for showers and storms as return
flow ahead of the wave increases. The best chance for storms will
be on the SD Plains, esp toward central SD where deeper moisture
will reside. This area will also see the better chances for strong
to severe storms given decent shear profiles. Upper trough will
linger over the area Thur with cool conds and chances for showers
per cold pool aloft. CAPE will be limited, hence not expecting any
severe weather. Things will then dry out into the weekend with
warmer temps.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Tuesday)
Issued At 1110 AM MDT Mon Jul 1 2024

Scattered showers and thunderstorms will develop this
afternoon across northeastern WY and far western SD, spreading
east into central SD by early evening. Storms are expected to exit
the CWA by 02Z. Gusty, erratic winds will accompany any stronger
cores along with MVFR/transient IFR conditions. Outside of
thunderstorms, VFR conditions will prevail through the forecast
period.

&&

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

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...Pojorlie