995
FXUS63 KUNR 230005
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
605 PM MDT Sun Jun 22 2025

.KEY MESSAGES...

- Chance of thunderstorms this afternoon and evening across southern
SD
- Unsettled this week with seasonable temperatures and a slight
  risk (2 out of 5) of severe thunderstorms Tuesday

&&

.DISCUSSION...(This Evening Through Sunday)
Issued at 117 PM MDT Sun Jun 22 2025

Upper low over ID places the northern plains in SW
flow, with an upper jet streak to our west. At the surface, low
pressure is over south central SD, with breezy NW winds across the
CWA. Low clouds persist over much of the area, resulting in cool
temperatures: 60s over northeastern WY, northwestern SD, and BH;
meanwhile, south central SD is in the 80s.

With persistent low clouds and cooler temperatures across
southwestern SD, confidence is low on severe storms developing
there this afternoon/evening. Buoyancy will be very weak, but
shear will be strong, so it`s not out of the question for a strong
to severe storm to develop as the shortwave pushes through early
this evening. This would be more likely across south central SD,
where MLCAPE is expected to be 500-1000 J/kg.

High pressure moves in Monday, resulting in a mild and calm day.
Highs will be in the 70s, with 60s in the BH. Meanwhile, a low
pressure system will come ashore over CA and begin sending shortwave
energy our way. This could spark some weak showers/storms over
northeastern WY Monday night.

Return flow will bring warm/moist air into the region Tuesday. Up to
1500 J/kg MLCAPE is expected to develop across northeastern WY,
where the cap will be weakest. With 0-6 km shear around 60 kts,
strong to severe storms will be possible as a shortwave pushes into
the western CWA Tues afternoon. Showers/storms could persist into
Tuesday night and Wednesday, as shortwave energy continues to pass
over the region. Beneath transient ridging Thurs/Fri, a warming
trend and mostly dry weather is expected. However, the upper-level
pattern remains messy into next weekend, so expect at least
occasional showers/storms each day.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Monday Evening)
Issued At 604 PM MDT Sun Jun 22 2025

Isolated to scattered showers and thunderstorms will become more
numerous this afternoon and early evening with localized MVFR to
IFR conditions, particularly across southern SD.

&&

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

$$

DISCUSSION/KEY MESSAGES...Pojorlie
AVIATION...Dye