730 

ACUS01 KWNS 191300

SWODY1

SPC AC 191258



Day 1 Convective Outlook  

NWS Storm Prediction Center Norman OK

0758 AM CDT Tue May 19 2026



Valid 191300Z - 201200Z



...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN

PLAINS INTO THE LOWER MISSISSIPPI VALLEY/MID-SOUTH...OHIO

VALLEY...AND LOWER GREAT LAKES...



...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.



...Southern Plains into the Lower Mississippi Valley...

Numerous thunderstorms are ongoing this morning across

central/eastern OK into northwest AR and southern MO. Most of this

activity is occurring along and north of a southward-moving cold

front, and should therefore pose a limited severe risk in the short

term. Eventual regeneration along the cold front and/or

strengthening of ongoing activity should occur later today across TX

into the lower MS Valley/Mid-South. Mid-level flow is forecast to

remain fairly modest, and deep-layer shear for most areas will tend

to be marginal. Still, filtered daytime heating of a moist low-level

airmass will support moderate to strong instability along/ahead of

the front by early afternoon. Scattered severe/damaging winds should

be the main threat with loosely organized clusters and bowing line

segments. This wind threat may continue to the TX/LA Coast this

evening/overnight. Some potential for supercells should also exist

across parts of west-central TX and vicinity, where steeper

mid-level lapse rates and greater instability is forecast to be in

place. Large hail appears possible with any supercells that can be

sustained, and isolated 2+ inch diameter hail may occur. With time

this evening, this convection may also grow upscale into a bowing

cluster and pose a greater severe wind risk.



...Ohio Valley into the Lower Great Lakes and Northeast...

Modestly enhanced mid-level southwesterly flow will be present today

over the OH Valley and lower Great Lakes regions, as a positively

tilted mid/upper-level trough moves from the Upper Midwest into

eastern Canada. Isolated to scattered thunderstorms should develop

along/ahead of a surface cold front this afternoon as the

pre-frontal airmass gradually destabilizes. Stronger instability

should be present this afternoon across the OH Valley, but greater

deep-layer shear may tend to remain mostly displaced farther north.

Even so, some thunderstorm organization should occur, with

multicells and bowing line segments possible. Scattered

severe/damaging winds should be the main threat, although isolated

hail could occur with the strongest cores. This convection should

spread into the lower Great Lakes by mid to late evening, before

eventually weakening across the Northeast late tonight. A separate

area of convection may develop this afternoon across parts of New

England, and also pose a threat for mainly occasional damaging

winds.



..Gleason/Marsh.. 05/19/2026



$$