225
FXUS63 KUNR 251724
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1124 AM MDT Sat Jul 25 2026

.KEY MESSAGES...

-Blocking pattern will support a large ridge of high pressure
 over the western CONUS into next week, with very hot temperatures
 and fire weather concerns at times

-Severe thunderstorms are possible this afternoon and evening
 from the Black Hills east, with damaging winds being the main
 threat

-Fire weather concerns today with high based dry thunderstorms
 possible

-Thunderstorms will be possible at times into next week as
 monsoon impulses advect around the ridge and into the region

&&

.DISCUSSION...(This Afternoon Through Friday)
Issued at 1106 AM MDT Sat Jul 25 2026

Upper level ridge will remain anchored over the Rockies into the
Plains supporting hot temperatures. Very hot temps the next two
days as the core of the thermal ridge passes over the region.
Expect temps into the 100s on most of the SD Plains and portions
of the WY Plains. Heat products look good most areas, did expand
the extreme heat warning west a couple zones given hotter than
expected temps, with heat index readings of 105 to 110 expected
there. A stronger shortwave filled with monsoon moisture will
advect around the ridge in SW flow and across the FA today,
supporting high based TS. Damaging winds will be possible with
thunderstorms given very high based nature and resultant
inverted-V profiles per drying BL. Sct wind gusts over 60 mph
(possibly over 80 mph in stronger cells) will be possible given
DCAPE over 2000 J/KG, esp on the SD Plains east of the Black
Hills. Not much rain expected with these cells, which will support
critical fire weather conds when coupled with dry fuels,
downburst winds, and low RH. Things will dry out tonight, but it
will remain very warm with lows in the 70s at many areas, with 80s
in the BH foothills. Another hot day Sunday with dry conds most
areas. The exception will be over the BH where diurnal convection
will be possible and with another impulse toward the evening and
overnight. Convection will be possible with this wave mainly in
the western third. Expect gusty winds once again. Ridge will
retrograde back west some by mid next week, supporting slightly
cooler but still hot temps as highs in the 90s are expected.
Isold-sct TS chances will continue as the lee trough interacts
will passing impulses. Main threat from storms will be strong
gusty winds given high LCL`s and inverted V profiles.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Sunday)
Issued At 1119 AM MDT Sat Jul 25 2026

Isolated to widely scattered thunderstorms are possible this
afternoon into the early evening from the Black Hills east onto
the western SD plains. These storms will be high based with little
rainfall expected. Main threat will be gusty winds possibly
exceeding 50kts at times. Not confident enough in exact location
to insert TSRA into KRAP terminal fcst.

Otherwise VFR conditions will prevail through the valid forecast
period.

&&

.FIRE WEATHER...
Issued At 1106 AM MDT Sat Jul 25 2026

Very hot temperatures will persist into next week as a ridge of
high pressure remains over the region. This will support elevated
to critical fire weather conditions as RH`s drop into the teens on
the Plains each day. Winds will be marginal most days, breeziest
Sunday on the SD Plains behind a trough where winds could gust to
30 mph for period. Poor recovery can also be expected most nights
across portions of northeast WY, the Black Hills, and far western
SD given warm overnight lows. In addition, there will be near
daily chances for isolated thunderstorms as batches of mid level
monsoon moisture push through the region. Storms may produce very
little rainfall and gusty winds, supporting a dry lightning threat
at times. This is especially the case this afternoon and evening
across northeast WY and western SD. TS`s will produce very little
rainfall and gusty/erratic winds. Wind gusts over 50 mph will be
possible with any cells, potentially higher with stronger cells. A
red flag warning remains in effect.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory until 8 PM MDT Sunday for SDZ001-002-012>014-
     025>027-030-031-041-042-072>076-078.
     Red Flag Warning until midnight MDT tonight for SDZ319>333.
     Extreme Heat Warning until 8 PM MDT /9 PM CDT/ Sunday for SDZ032-
     043-044-046-047-049-077.
WY...Heat Advisory until 8 PM MDT Sunday for WYZ054>056-058>060.
     Red Flag Warning until midnight MDT tonight for WYZ314>318.
&&

$$

DISCUSSION...JC
AVIATION...Hintz
FIRE WEATHER...JC