969
FXUS63 KFSD 242337
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
637 PM CDT Mon Aug 24 2026

.KEY MESSAGES...

- An isolated severe storm is possible this evening into the
  overnight, with better chances in central SD and also near
  and north of Highway 14. An isolated stronger storm may also
  develop across portions of northwest Iowa/southwest Minnesota
  late Tuesday afternoon.

- Seasonable temperatures through the week ahead with highs in
  the upper 70s and 80s, and lows in the upper 50s to mid 60s.

&&

.DISCUSSION...
Issued at 143 PM CDT Mon Aug 24 2026

Showers and thunderstorms are possible tonight into early Tuesday
morning as a wave skirts by to the north and west. For early this
evening, instability grows across central SD, with CAPE values of
2000-3000 J/kg, but only marginal shear. Initially storms will be
most likely west of the area, but some development could creep into
Gregory and Brule counties. Capping may preclude any development,
so only low confidence in storms actually developing. Later
tonight into early Tuesday morning a tail of convection could
build south towards highway 14 and into pars of southwest MN.
Here CAPE values of about 1000-1500 J/kg will be possible with
minor-moderate shear. Some question as the whether we see an
increase in moisture around 800 mb which appears to be needed to
produce a few updrafts. Once again this is somewhat lower
confidence set up. Isolated severe weather will be possible in
bth areas, half dollars and 70 mph winds in central SD and
quarters and 60 mph winds in southwest MN.

Warmer air aloft builds into the area Tuesday, but other than northwest
IA the threat for showers and thunderstorms will be fairly low.
If there is some elevated moisture there could be a little
activity in the morning. Northwest IA may see just enough
instability and shear on Tuesday afternoon for a couple of
strong to severe updrafts.

Behind this cooler and drier air builds into the area which appears to
bring dry and seasonally mild conditions for Wednesday and Thursday.

Stronger westerly winds aloft will spread across the area Friday into
the weekend. This should bring occasional chances for showers
and thunderstorms during this time. Friday night appears to be a
better chance right now. As the warmer conditions and somewhat
deeper instability build in Friday night into Saturday isolated
severe storms will be possible.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 636 PM CDT Mon Aug 24 2026

VFR conditions are expected for the majority of the period. Showers
and thunderstorms have developed across central South Dakota
and Nebraska along a cold front. These showers are expected to
travel slowly east with the front over the next 24 hours. As
they do they will encounter an increasingly stable environment.
In addition soundings indicate a fairly dry airmass in place.
These things combined result in low confidence in storms at any
of the TAF sites. However, should these storms become elevated
and enough moisture advects in ahead of the front at the 850 mb
level elevated strong to severe storms could be form.

Winds are currently out of the southeast and intermittently
gusting up to 22 kts. Gusts will quickly decrease as daytime
heating is lost, then winds will become light and variable
overnight. Winds will become diurnally breezy Tuesday afternoon
out of the northwest, gusting 17-22 kts.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...08
AVIATION...AJP