Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0740 AM CDT Fri Apr 03 2026
Valid 031300Z - 041200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN
MISSOURI AND SOUTHERN IOWA INTO WEST/NORTHWEST ILLINOIS...
...SUMMARY...
A few tornadoes and isolated very large hail are possible late this
afternoon and evening across northern Missouri into southern Iowa
and north-central Illinois with any sustained supercells that
develop. Storms are otherwise expected to evolve into an extensive
line by Friday evening from Iowa to Oklahoma and northwest Texas,
with the primary threats of large hail and damaging winds.
...Northern Missouri/southern Iowa/north-central Illinois...
The shortwave trough emerging from the north-central High Plains
this morning will spread east-northeastward toward the Upper Midwest
through early Saturday. This will be accompanied by a strengthening
(70+ kt) belt of cyclonically curved mid/high-level westerlies. A
surface low across the south-central Plains will transition
northeastward toward the Iowa/Illinois border vicinity tonight,
while a warm front shifts northward from northern Missouri into Iowa
and across northern portions of Illinois/Indiana, where low/middle
60s F dewpoints will become common across the Midwest near and south
of the warm front.
Within the warm sector, residually steep mid-level lapse rates and
modest insolation will contribute to MLCAPE values up to 2000 J/kg
(and MUCAPE values approach 3000 J/kg). Deep-layer shear will be
sufficient for supercells along and south of the warm front and east
of the Pacific cold front/dryline. While the likelihood/extent of
semi-discrete supercellular development remains a bit uncertain, the
main potential for such will increase during the afternoon near the
triple point around the Kansas/Missouri/Iowa border vicinity and
eastward, potentially as far east into western/north-central
Illinois in vicinity of the northward-shifting warm front.
Semi-discrete development would offer tornado/very large hail
potential, as well as a possible multi-round scenario of severe
storms in some of this corridor via a more prevalent line of storms
during the evening, with a damaging wind risk and some continued
tornado potential as the low-level restrengthens.
...Northern Indiana to western portions of Pennsylvania/New York...
Relatively strong westerlies atop the frontal zone, which will be
more southeast-progressive as a cold front with eastward extent,
will support at least isolated severe thunderstorms late this
afternoon into evening, including a few supercells regionally.
...Southeast Kansas/Southwest Missouri to Northwest Texas...
Thunderstorms will develop southward from northern Missouri into
Oklahoma during the afternoon as the Pacific cold front/dryline
advances southeastward into an increasingly unstable airmass. At the
same time, additional thunderstorms are likely to develop across
Northwest Texas and southwest Oklahoma in association with a subtle
perturbation within the subtropical jet. Forecast wind fields
indicate low-level flow will be weaker here than areas farther north
and east. The combination of this wind field and the widespread
nature of the convection would lend itself to large hail and
damaging winds as the main severe hazards, although a tornado could
occur with any discrete storm or along the leading edge of any
organized linear segments.
...Southwest Texas...
Isolated thunderstorms are expected by late afternoon and early
evening in vicinity of the dry line and near some of the
mountains/higher terrain. Wind fields will support supercells
capable of producing large hail and localized severe-caliber winds.
..Guyer/Weinman.. 04/03/2026
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