ACUS11 KWNS 032159
SWOMCD
SPC MCD 032159=20
INZ000-ILZ000-040000-

Mesoscale Discussion 0344
NWS Storm Prediction Center Norman OK
0459 PM CDT Fri Apr 03 2026

Areas affected...Central portions of Illinois into central and
northwest Indiana

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

Valid 032159Z - 040000Z

Probability of Watch Issuance...60 percent

SUMMARY...The severe threat may increase into the evening hours,
though the overall intensity and coverage of storms remains
uncertain at the moment.

DISCUSSION...Multicells and transient supercells persist along an
east-to-west oriented baroclinic zone across central IL/IN. These
storms are developing amid a moist boundary layer, characterized by
upper 60s F dewpoints amid small T/Td spreads, with over 1500 J/kg
MLCAPE present. The upper trough is currently displaced relatively
far to the west, so shorter term forcing mechanisms are
predominantly from stronger surface heating, and the ILX/IND VADs
currently depict short and modestly curved hodographs. The current
thinking is that storms should remain at their current degree of
organization and intensity for at least the next couple of hours.
Transient circulations potentially supporting isolated, brief
tornadoes is the most immediate threat.=20

A few hours from now, into the evening hours, the gradual approach
of the upper trough will support a substantial strengthening of the
850 mb flow (i.e. southerly low-level jet), especially in the 00-06Z
time frame. Should discrete, surface based storms persist in this
time frame, it is plausible that appreciable strengthening and
organization of supercell structures with sustained low-level
mesocyclones may be achieved. Such storms may pose a locally greater
tornado threat in addition to severe wind/hail. However, such a
threat is dependent on storms remaining surface based, with boundary
layer stabilization only gradually taking place. As such,
uncertainty remains. However, convective trends will continue to be
monitored through the evening hours as the low-level jet
intensifies.

..Squitieri/Smith.. 04/03/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!9n4dyXzRCW4z34YBMKv4nn-PHgl_Xp7Xbm9YXBCREFhbEBIZHIzeYVurkxPRvTglKHXncr7tJ= ALzHOQiA3_gjVgdnsw$ for graphic product...

ATTN...WFO...IWX...IND...LOT...ILX...LSX...DVN...

LAT...LON 41219007 41558879 41278654 40818576 40368573 39968598
39798676 39768817 39708945 39729011 39979053 40909034
41219007=20

MOST PROBABLE PEAK TORNADO INTENSITY...85-115 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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