Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0102 AM CDT Thu Apr 02 2026
Valid 021200Z - 031200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS EASTERN
IOWA...NORTHERN ILLINOIS...AND FAR SOUTHERN WISCONSIN...
...SUMMARY...
Severe thunderstorms capable of producing a few tornadoes appear
probable across parts of eastern Iowa, northern Illinois, and
southern Wisconsin this afternoon. Additionally, damaging
thunderstorm winds will be possible from eastern Iowa northeast into
Michigan.
... Overview ...
A negatively tilted trough will quickly lift northward through the
Plains and across the Great Lakes today and tonight. As this occurs,
a modest surface low will race northeast from north-central Kansas
this morning into Ontario by Friday morning. Attendant to this
surface low, a west-east oriented warm front will lift northward
across the Great Lakes during the day and a north-south cold front
will push east across the region during the late afternoon and
overnight.
... Eastern Iowa east-north into Michigan ...
A strong low-level jet at the start of the forecast period will
support widespread showers and thunderstorms across the area. The
low-level jet will strengthen through the morning as the midlevel
trough approaches and the H850 low intensifies. This will maintain
showers and thunderstorms through at least midday across Iowa and
Illinois before the H850 low moves far enough north and east for the
core of the low-level jet to focus farther east, taking the
precipitation with it.
In the wake of the morning/early afternoon convection, a narrow
corridor of destabilization should occur across central/eastern Iowa
and northwest Illinois to the south of the warm front and east of
the cold front. Scattered supercells are expected to develop along
the cold front during the afternoon where MUCAPE in excess of 1000
J/kg and deep-layer shear on the order of 45 knots exists. Strong
low-level kinematic fields will support a tornado and wind threat
with these initial storms, and, despite modest lapse-rates, the
presence of supercells within a modestly unstable environment will
support some hail potential.
By late afternoon/early evening these supercells should move into a
less stable environment characterized by decreasing CAPE but
increasing low-level shear. Current expectation is that the initial
discrete storms will eventually grow upscale into one or more linear
segments, along the advancing cold front. Despite the decreasing
instability, the strength of the low-level wind field will support a
continued wind threat eastward into Lower Michigan during the
evening and overnight hours.
... Northeast Arkansas, Southeast Missouri, western Tennessee, and
western Kentucky ...
Isolated thunderstorms will be possible during the afternoon along
and ahead of the surface cold front, where modest warm-air advection
is forecast to persist through the day. Despite weakening kinematic
fields, deep-layer shear on the order of 30 knots and MUCAPE between
1000-2000 J/kg will support at least some severe potential --
including a tornado or two -- during the late afternoon and early
evening.
..Marsh/Chalmers.. 04/02/2026
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