Fort Pierre, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

296
FXUS63 KUNR 230751
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
151 AM MDT Mon Jun 23 2025

.KEY MESSAGES...

- Nice today, but TSRA return tonight
- Slight risk (2 out of 5) of severe thunderstorms Tuesday
  afternoon/evening
- Unsettled for the rest of the week with trends pointing toward
  warmer/hotter weather for Thursday through Saturday

&&

.DISCUSSION...(Today Through Sunday)
Issued at 149 AM MDT Mon Jun 23 2025

07z surface analysis had cool front well southeast of the CWA
with modest high building from the Rockies into the northern
Plains. Water vapour loop had upper trough from southwest Canada
into southwest CONUS. Tail end of shortwave over the eastern
Dakotas with decreasing shra/TS over south-central SD per regional
radar loop. Main forecast concern this week revolves around
severe potential.

Today, subsidence/drying in wake of shortwave leading to a nice
day with near seasonal temperatures, which will be close to
guidance. Tonight, southwest CONUS shortwave moves into the
Rockies with weak low developing over CO, promoting weak low level
jet/theta-e advection into the region. Elevated TSRA will occur.
Lows tonight will be near guidance.

Tuesday, shortwave moves into WY allowing surface low to slowly
deepen and a warm front to develop ahead of it extending from
north-central WY into the NE panhandle by afternoon.
Southeasterly low level flow will be topped by southwesterly mid-
level flow lengthening hodographs with 40-50+kts 0-6km bulk shear.
1-2KJ/kg SBCAPE forecast by afternoon. When cap breaks (it should
given warm front/shortwave approaching), supercells are a good
bet over northeastern WY, which will support large (possible very
large) hail and damaging wind gusts as they move east around 20kts
(right mover) or northeast around 25kts (left mover). Forecast
hodographs suggest splitting storms may occur. 0-1km shear not
sounding the tornado klaxon, but with northeastern WY positioned
near the warm front and northeast of the surface low, conditions
may become favorable for isolated tornadoes. How far east the
severe storms make it in question given less favorable
environment further east in western SD. Temperatures will be near
guidance.

Wednesday, another shortwave will move through with additional
TSRA chances. Wouldn`t be surprised to see active storms given
pattern with CSU MLP and SPC painting potential for severe
hail/wind. Thursday through Saturday, ensemble guidance trends
have been trending hotter, especially Friday, but confidence in
details not particularly high given 5-10F temperatures spreads in
NBM guidance. Generally drier weather foreseen, but a stronger
system/cold front may drop late Saturday with higher PoPs.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Monday Night)
Issued At 1002 PM MDT Sun Jun 22 2025

Scattered showers and storms over parts of the western SD plains
tonight will taper off from west to east in the overnight hours.
Localized MVFR to IFR conditions will be possible in storms.
Otherwise expect VFR conditions through the TAF period.

&&

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

$$

DISCUSSION/KEY MESSAGES...Helgeson
AVIATION...Dye