Mesoscale Discussion 1735
NWS Storm Prediction Center Norman OK
0735 AM CDT Sun Jul 20 2025
Areas affected...Portions of far east-central IL into central IN
Concerning...Severe potential...Watch possible
Valid 201235Z - 201430Z
Probability of Watch Issuance...40 percent
SUMMARY...A small complex of thunderstorms may pose a gradually
increasing threat for damaging winds over the next few hours. Watch
issuance is possible later this morning if this activity can
intensify.
DISCUSSION...Thunderstorms are ongoing this morning across parts of
central IL, aided by modest west-southwesterly low-level warm
advection and a low-amplitude mid-level perturbation. This
convection should continue to track generally east-southeastward
this morning across parts of central IN along an instability
gradient evident in latest mesoanalysis. While low/mid-level flow is
not overly strong, recent VWPs from KILX/KIND do show some
strengthening with height through mid levels. Resultant 25-30 kt of
effective bulk shear should continue to support some updraft
organization, with a recent supercell structure noted with a
thunderstorm near the IL/IN border. If a small bowing cluster can
become established as some recent high-resolution guidance suggests,
then a greater threat for scattered severe/damaging winds may be
realized across parts of central IN later this morning as the
boundary layer gradually destabilizes with filtered daytime heating.
While not immediately likely, Severe Thunderstorm Watch issuance may
eventually be needed if the ongoing activity can intensify.