ACUS11 KWNS 042043
SWOMCD
SPC MCD 042042=20
OHZ000-MIZ000-INZ000-ILZ000-WIZ000-IAZ000-042245-

Mesoscale Discussion 0638
NWS Storm Prediction Center Norman OK
0342 PM CDT Mon May 04 2026

Areas affected...portions of the Midwest and southern Great Lakes

Concerning...Severe potential...Watch possible=20

Valid 042042Z - 042245Z

Probability of Watch Issuance...40 percent

SUMMARY...Widely scattered to scattered thunderstorm development is
expected late this afternoon, with potential for severe/damaging
wind gusts and large hail. Watch issuance is possible for a portion
of the discussion area.

DISCUSSION...Prevailing southwesterly flow has yielded modest
moisture return across portions of the Midwest into the southern
Great Lakes region, with dewpoints climbing into the 40s/low-50s.
While a surface cold front remains displaced to the northwest,
expectation is for widely scattered to scattered strong to severe
thunderstorms to develop within the warm conveyor this afternoon as
convective temperatures are reached and remaining inhibition is
removed. A 700-mb speed max associated with an approaching shortwave
trough will help to promote 30-40 kts of effective bulk shear across
the region, with MLCAPE forecast in the 500-1250 J/kg range. This
will be sufficient to support storm organization into
multicells/clusters and perhaps transient supercell structures;
although, the lack stronger flow aloft and limited hodograph
elongation is likely to limit supercell intensity/persistence.

Dry mid-level air and well-mixed boundary layers (as sampled by
regional ACARS profiles and the 18z DVN observed sounding) will
support a risk for severe/damaging wind gusts. Large hail will also
be possible given modestly steep mid-level lapse rates (>7 C/km per
latest mesoanalysis). While a strengthening of 850 mb flow and some accompanying increase in low-level hodograph curvature is expected
this evening (especially across northern Indiana and northwest Ohio
within the 21-00z time frame), the tornado threat remains uncertain
owing to the expectation for boundary layer moisture quality to
remain more limited across the region.=20

Thus, given the potential for these hazards, a Severe Thunderstorm
Watch is possible for a portion of the discussion area, particularly
from northeastern Illinois into northwestern Ohio where the
potential coverage of severe hazards appears greater.

..Chalmers/Smith.. 05/04/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!-FEslyVCZ2k6ZuZuK1CnXnj65zLXJVywzU4Jbfhx8L5NlU1g6BSGSgUv6j2_8knN6NcfShmmA= QYmeLUocDAWaEKq9Jw$ for graphic product...

ATTN...WFO...CLE...ILN...DTX...IWX...GRR...IND...LOT...ILX...
MKX...DVN...

LAT...LON 40518958 40679037 41009087 41529106 42019081 42459004
42658882 42808808 42928668 42858577 42578475 42178393
41858341 41368312 40998314 40728341 40518462 40438591
40448725 40458834 40478912 40518958=20

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


=3D =3D =3D
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