Winner, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

227
FXUS63 KUNR 130849
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
249 AM MDT Fri Jun 13 2025

.KEY MESSAGES...

-Areas of fog early this morning, mainly on the SD Plains

-Unsettled into next week with near daily chances for showers and
 storms, some possibly severe at times

-Seasonal temps most of the period

&&

.DISCUSSION...(Today Through Thursday)
Issued at 247 AM MDT Fri Jun 13 2025

Upper air analysis shows near zonal flow across the northern Plains,
transitioning to WSW flow over the western CONUS ahead of a stalled
PAC coast trough. Southerly low level flow continues across the
Great Plains, which is advecting in warm/moist air into the region.
Webcams/surface obs shows fog developing across portions of the
western SD plains into the northern/eastern foothills of the Black
Hills. Fog will dissipate by mid morning today. A shortwave over
Idaho will be the next one to bring storms to the CWA today. Models
continue to show southeasterly low-level flow w/ a corridor of
enhanced Theta E stretching from SW SD through NE WY. Across this
area, MLCAPE of 1500-2000 J/kg and sufficient bulk shear will
support some supercell development in the late afternoon/early
evening hours. Large hail and damaging winds will be the main
threats today, but can`t completely rule out a tornado with some
pockets of higher 0-1k shear where surface winds become more
easterly. Convection will move east across the Black Hills area
around sunset. Then storms will push into the western SD plains in
the evening along an axis of increasing Theta E advection. The
threat will become more wind-based across the SD plains. Another
shortwave will cross the upper level southwesterly flow on Saturday.
CAMs show storm development across northeast WY and the Black Hills
Sat afternoon, then pushing eastward across the western SD plains in
the evening, mainly south of I-90. Large hail and damaging winds are
again the main threats, then becoming more wind based east of the
Black Hills. Daily chances of strong/severe storms are expected
early next week, as little change to the overall pattern is
expected.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Friday Night)
Issued At 936 PM MDT Thu Jun 12 2025

Thunderstorms may move into northeastern WY and southwestern SD
tonight, with brief MVFR conditions possible.

Low stratus with MVFR/IFR CIGS across NW SD will spread southwest
into the Black Hills region tonight, with patchy fog reducing
VSBY. Conditions will gradually improve to VFR Friday afternoon.

Another round of thunderstorms will be possible across northeastern
WY and far western SD Friday evening.

&&

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

$$

DISCUSSION/KEY MESSAGES...13
AVIATION...Pojorlie