Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0253 PM CDT Tue May 19 2026
Valid 192000Z - 201200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
OHIO VALLEY INTO THE LOWER GREAT LAKES...AND PARTS OF CENTRAL/SOUTH
TEXAS...
...SUMMARY...
Scattered severe thunderstorms will be possible today from the
southern Plains into the lower Mississippi Valley/Mid-South, Ohio
Valley, and lower Great Lakes. Damaging winds and hail will be the
primary threats. A greater threat for large to very large hail
should exist across parts of west-central Texas.
...20Z Update...
The primary change to the forecast was to increase wind
probabilities in parts of South Texas. Convection within the Rolling
Plains should continue to develop this afternoon along a slowly
moving cold front. Given the moisture surge ahead of this activity,
it seems plausible that cold pool development will be robust enough
to support continued development southward into the overnight.
Recent HRRR guidance and the ECMWF support this possibility.
Elsewhere, only minor changes where made based on current
observations.
..Wendt.. 05/19/2026
.PREV DISCUSSION... /ISSUED 1119 AM CDT Tue May 19 2026/
...OH Valley and Lower Great Lakes...
Deep southwesterly flow is present today from southern IL into much
of the OH Valley and NY. Visible satellite imagery shows mostly
clear skies in the region, allowing strong destabilization and
steepening low-level lapse rates. The result will be a rather large
zone of favorable environment for strong/damaging wind gusts this
afternoon with any organized convection. Given the continued trend
in morning model guidance of scattered clusters of storms in this
corridor, the SLGT risk area has been maintained.
...South-central TX...
A warm/moist and unstable air mass will develop this afternoon
across parts of west-central TX. Scattered thunderstorm development
is expected along a cold front sagging into the region. with weak
supercells structures possible. These storms will track
southeastward through the late afternoon/evening with a large hail
threat. Eventual upscale growth into bowing structures may extend
the severe risk overnight into south-central TX.
...East TX/LA/AR...
Widespread overnight convection continues to build southeastward
across southeast OK and western AR. This activity will persist much
of the day and spread across much of AR/East TX/northern LA, in a
region of relatively weak vertical shear and poor lapse rates.
Storms may occasionally pose a risk of gusty/damaging winds, but the
overall threat appears marginal.
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