168 

ACUS02 KWNS 180556

SWODY2

SPC AC 180554



Day 2 Convective Outlook  

NWS Storm Prediction Center Norman OK

1254 AM CDT Mon May 18 2026



Valid 191200Z - 201200Z



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

LAKES TO THE SOUTHERN PLAINS...



...SUMMARY...

Widely scattered severe thunderstorms will be possible along a cold

front extending from the Great Lakes into the Ohio Valley and the

southern Plains on Tuesday. Damaging winds and large hail will be

the primary threats.



...Synopsis...

A mid-level trough will lift across the Great Lakes Region on

D2/Tuesday with a surface low moving east across southern Ontario

and Quebec. A trailing cold front will be located from the Great

Lakes south into the Ohio and mid Mississippi Valleys into the

Southern Plains. Convection will likely be ongoing across this

boundary at the beginning of the D2/Tuesday period. 



...Great Lakes Vicinity to the Lower Ohio Valley...

Some convection may be ongoing across the cold front towards the

beginning of the D2 period, with additional development likely by

the afternoon along the eastward shifting cold front. Enhanced

mid-level flow aloft and weak to moderate instability will support

organized storms with potential for damaging winds and isolated

large hail. Additional afternoon thunderstorm development may extend

into the Northeast with potential for large hail and damaging wind.



...Mid Mississippi Valley to Southern Plains...

Convection will be ongoing at the start of the period from the mid

Mississippi Valley driven by the cold front and potential cold pool

propagation. These boundaries will be the focus of

re-intensification of convection in the afternoon. Mid-level flow

aloft will be weaker across the region but sufficient shear for

organization should remain in place. A plume of more favorable

moderate to strong instability will be available across

central/northern Texas into southern Oklahoma. With afternoon

development, steep low to mid level lapse rates and moderate

instability will support potential for a few large hail reports.

With time, upscale growth will support a downstream damaging wind

risk.



..Thornton.. 05/18/2026



$$