ACUS11 KWNS 171950
SWOMCD
SPC MCD 171949=20
WIZ000-IAZ000-MNZ000-172145-

Mesoscale Discussion 0476
NWS Storm Prediction Center Norman OK
0249 PM CDT Fri Apr 17 2026

Areas affected...central/eastern Iowa into southeastern Minnesota

Concerning...Tornado Watch 129...

Valid 171949Z - 172145Z

The severe weather threat for Tornado Watch 129 continues.

SUMMARY...Threat for large to very large hail, wind, and tornadoes
continues within WW129.

DISCUSSION...Thunderstorm activity has increased along the cold
front in central Iowa into southeastern Minnesota. Mode is rather
mixed, with clusters and more semi-discrete supercells along and
ahead of the front. Reports of large hail 1-1.75 inches in diameter
and a tornado were reported near Olmstead, MN. The threat for large
hail, tornadoes, and damaging wind will continue over the next
several hours. Daytime heating and warm air advection has yielded
MLCAPE around 2000-3000 J/kg. The 18z RAOB from DVN shows this well,
with analyzed 2100 J/kg MLCAPE, steep low to mid-level lapse rates
and an enlarged clock-wise low-level hodograph.

As the front moves eastward and mode shifts to become more linear,
the main threats will shift to damaging wind and continued potential
for line embedded tornadoes. With any supercells that can maintain
ahead of the line (particularly from eastern Iowa into southern
Wisconsin), large hail, and strong tornado potential will continue.

..Thornton.. 04/17/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!9M5SBdhyDa_3b-Cx4mmQk5DdMjinsidWXaRiSxJbLWFXuav36CYXFlA42_-1RbTaWvlzzChkn= MSTt7pHB59fhxFE5Ys$ for graphic product...

ATTN...WFO...DVN...ARX...MPX...DMX...

LAT...LON 44689181 44719166 44089098 43199071 42469086 41279180
40809269 40839376 41469364 43379278 44239250 44559207
44689181=20

MOST PROBABLE PEAK TORNADO INTENSITY...120-150 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN


=3D =3D =3D
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