647
FXUS63 KUNR 112338
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
538 PM MDT Fri Jul 11 2025

.KEY MESSAGES...

-Dry this weekend with temperatures climbing back into the 90s

-Daily chances of afternoon thunderstorms return to the forecast
 next week

-Chance of strong to severe thunderstorms possible Tuesday

&&

.DISCUSSION...(This Evening Through Next Friday) Issued at 115 PM
MDT Fri Jul 11 2025

Current analysis shows a broad upper trough continuing to
influence much of the region, maintaining cooler than normal
average temperatures and scattered to widespread showers with
embedded thunderstorms across much of western South Dakota and
northeastern Wyoming. A pattern shift is expected heading into the
weekend as a strong upper ridge builds over the central CONUS,
allowing for a period of hot and dry conditions. This ridge will
begin to break down early next week, allowing daily thunderstorm
chances to return, with a risk of more organized storms by
Tuesday.

Cloud cover and lingering showers are progged to continue through
today as the upper trough slowly exits the region. Highs will
remain below seasonal norms, generally in the 60s and low 70s
across the plains, with cooler readings in the Black Hills. Patchy
drizzle and light rain will taper off by the evening as subsidence
increases behind the departing wave. The gusty northwest winds
will also decrease heading into the evening hours.

By Saturday, a pronounced upper-level ridge begins to build across
the central and northern Plains. This will result in a sharp
warming trend, with highs climbing into the upper 80s to mid 90s
across much of the forecast area. Sunday will be the hottest day
of the period, with widespread highs in the mid to upper 90s and
some triple-digit readings possible across the southern plains.
The ridge will begin to flatten late Sunday into Monday as
shortwave energy approaches from the Pacific Northwest. Starting
Monday, daily chances for afternoon and evening thunderstorms will
return, particularly across the Black hills and adjacent plains.
Moisture advection and increasing instability will support
convective development, though coverage may remain isolated early
in the week.

Tuesday will see the strongest shortwave trough passage as it
exits the northern Rockies and enters the northern Plains. This
system will bring enhanced shear and with a modest moist influx at
the surface instability increase to around 1500 J/kg Tuesday
afternoon. Organized strong to potentially severe thunderstorms
maybe possible across western South Dakota. Confidence in timing
and placement will improve by the end of the weekend.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Saturday Evening)
Issued At 533 PM MDT Fri Jul 11 2025

Generally VFR conditions are expected. The exception will be MVFR
conditions in scattered showers and isolated thunderstorms, which
will be possible across southern South Dakota, south and east of
KRAP through 06Z. Those showers and storms should move east of
KICR by 06Z, with VFR conditions expected across the entire area
through the end of the TAF period.

&&

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

$$

DISCUSSION/KEY MESSAGES...Woodward
AVIATION...15