Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1117 AM CDT Tue Sep 15 2026
Valid 151630Z - 161200Z
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS PARTS OF THE CENTRAL PLAINS AND MIDWEST....
...SUMMARY...
Strong to locally severe thunderstorms may occur from the
south-central Plains into parts of the Midwest this afternoon and
evening, with at least isolated damaging wind gusts possible.
...Central Plains into Midwest...
Moderately fast zonal flow remains across the northern US today,
with the primary surface boundary extending from the TX Panhandle
east-northeastward into parts of KS/MO/IL. This boundary will be
enhanced by daytime differential heating, and will provide the focus
for scattered thunderstorms along its length. Most of this activity
will be relatively disorganized, but in an environment of moderate
CAPE and steep low-level lapse rates favorable for occasional
strong/severe downdrafts.
One area of greater concern extends across northern MO into
west-central IL. Morning CAM solutions suggest higher confidence in
storm coverage in this area, and forecast soundings show sufficient
deep-layer shear for organized multicell or occasional supercell
structures. However, much of this activity may occur on the north
side of the baroclinic zone with slightly weaker support for intense
downburst winds. Warm temperatures aloft should limit hail concern.
Therefore, have opted to maintain the MRGL risk category and
re-evaluate at the 20z update.
..Hart/Chalmers.. 09/15/2026
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