ACUS11 KWNS 181948
SWOMCD
SPC MCD 181947
IAZ000-MNZ000-SDZ000-182145-

Mesoscale Discussion 2025
NWS Storm Prediction Center Norman OK
0247 PM CDT Tue Aug 18 2026

Areas affected...Far southeast South Dakota into southern Minnesota
and northern Iowa

Concerning...Severe potential...Watch possible

Valid 181947Z - 182145Z

Probability of Watch Issuance...40 percent

SUMMARY...While uncertainty in storm coverage remains, large hail
and damaging winds would be possible with storms that may develop
along the cold front. Convective trends will be monitored through
the afternoon for a possible watch.

DISCUSSION...Cumulus have been deepening near a weak mesoscale low
in southeast South Dakota. Additional cumulus towers have been
observed along the cold front farther east, though convergence is
much weaker and agitated cumulus have not been long lived. With
around 50 kt of shear and destabilization occurring south of the
front, large hail (potentially near 2 in.) and damaging winds would
be possible. The main question will be how many storms will be able
to form this afternoon. The weak surface convergence across much of
the front and upper-level clouds moving in from the west limit
confidence in this regard. Some CAM guidance has suggested storm
development along the front may be delayed until late
afternoon/early evening when a stronger southerly surge of the front
is expected. Convective trends will need to be monitored for a
possible watch.

..Wendt/Guyer.. 08/18/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!4BeZQvWIzFKLrQ2lufe8GSV5-M4Q-FPnt0Mo3Wo2zbxm1KeySKjDdEUtTf_CtGF9VV3Hy3mfk4Z5uR8VwvkROAO9ETA$ for graphic product...

ATTN...WFO...MPX...DMX...FSD...

LAT...LON 44159704 44409669 44019512 43939408 43669375 43429368
42739352 42499362 42499396 42569417 42629467 43159654
43899706 44159704

MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN


= = =
To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.
--- scorpsmtpd
* Origin: capitolcityonline.net * KY, USA (1:2320/107)