ACUS11 KWNS 130950
SWOMCD
SPC MCD 130949
IAZ000-NEZ000-131145-

Mesoscale Discussion 1965
NWS Storm Prediction Center Norman OK
0449 AM CDT Thu Aug 13 2026

Areas affected...parts of east central Nebraska into
central/southwestern Iowa

Concerning...Severe Thunderstorm Watch 580...

Valid 130949Z - 131145Z

The severe weather threat for Severe Thunderstorm Watch 580
continues.

SUMMARY...The risk for strong to severe wind gusts continues with an
organized cluster of storms moving along and north of the I-80
corridor into central Iowa through 6-7 AM CDT. Trends are
continuing to be monitored for the possibility of an additional
downstream severe weather watch.

DISCUSSION...The relatively compact mesoscale convective system has
been generally maintaining intensity and organization, based on
latest radar, satellite and lightning data. Intense westerly rear
inflow in excess of 80 kt, at least at mid-levels, persists to the
southwest of a MCV now crossing the Missouri River near Tekamah,
based on radar data from Des Moines. However, peak gusts reaching
the surface have weakened based on recent surface observations.
Still a gust to 48 kt was recorded at Tekamah, and given current
convective trends, there remains potential for downward momentum
transfer to contribute to strengthen strong to severe gusts near and
north of the I-80 corridor into central Iowa over the next few
hours.

Stronger forcing for ascent associated with lower/mid-tropospheric
warm advection is becoming focused to the rear/southwest of the
convective system. As near-surface updraft inflow begins to emanate
from a somewhat less moist/unstable air mass across and east of the
Greater Des Moines vicinity, potential evolution becomes more
uncertain. It is possible instability remains sufficient to
maintain vigorous convective development near the eastward migrating
MCV. Renewed strong thunderstorm development also might not be out
of the question a bit farther to the south and west, closer to the
nose of the lingering southerly low-level jet.

..Kerr.. 08/13/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!5IDbsMkvwG1yAsbWvmle0gPc81i48fU7tmFyshIvCX236mi0LFzrBfrLWpZVmqzW6L0krhK-DgVWhNVP_0xaT1x1V7A$ for graphic product...

ATTN...WFO...DMX...FSD...OAX...

LAT...LON 42189574 42259506 42049382 41599344 41139316 40979384
40949479 40839545 40999609 41699545 42189574

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 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)