ACUS11 KWNS 072329
SWOMCD
SPC MCD 072329
SDZ000-NEZ000-080100-

Mesoscale Discussion 2267
NWS Storm Prediction Center Norman OK
0629 PM CDT Mon Sep 07 2026

Areas affected...portions of southeastern South Dakota and far north-central/northeastern Nebraska

Concerning...Severe potential...Watch possible

Valid 072329Z - 080100Z

Probability of Watch Issuance...60 percent

SUMMARY...A threat for primarily large to very large hail and
perhaps a tornado exists across portions of southeastern South
Dakota and far north-central/northeastern Nebraska.

DISCUSSION...Isolated thunderstorm development has been noted near
the SD/NE border along a weak surface boundary/confluence zone in
the past 30-60 minutes. While the anticipated northeasterly motion
of this activity will result in developing storms crossing to the
cool side of a surface warm front, latest objective analysis and RAP
forecast soundings suggest that MUCAPE ranges from 2000 to as high
as 4000 J/kg across this region. Coupled with modestly steep
mid-level lapse rates around 7 C/km, ESRH of 200-400 m2/s2, and ~40
kts of effective shear, this environment favorable for primarily
large to very large hail. Clockwise-curved low-level hodographs may
also support a risk for a tornado should a supercell become rooted
in the boundary layer; although, this remains uncertain given the
presence of poor lapse rates and modest static stability within the
low-levels (particularly on the cool side of the warm front). Trends
will continue to be monitored, and a targeted WW may be needed
should ongoing activity continue to persist/intensify.

..Chalmers/Gleason.. 09/07/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fjg!8zhg2yv_RZJnOp950tqUwcPpusjPnyMiXc0lCTv8lrkUpNliEsvSDsoHQooax19qp55e3Ues0OFqNncagT7XwnbbT9U$ for graphic product...

ATTN...WFO...FSD...OAX...LBF...

LAT...LON 42729924 42899930 43329920 43989860 44189814 44269768
44149732 43899696 43549683 43109696 42799763 42729808
42619886 42729924

MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN


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