ACUS01 KWNS 150534 SWODY1 SPC AC 150532 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1232 AM CDT Thu Oct 15 2026 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE MID MISSISSIPPI VALLEY INTO THE OHIO VALLEY...AND OVER PARTS OF THE SOUTHERN PLAINS... ...SUMMARY... Thunderstorms with isolated severe wind gusts and perhaps a tornado or two are possible today across parts of the mid Mississippi and Ohio Valleys. Additional storms with isolated severe wind gusts will be possible in parts of the southern Plains. ...Mid Mississippi and Ohio Valleys... At mid-levels, a ridge will move eastward today into the Northeast, as a large-scale trough moves into the Great Plains. Ahead of the trough, a surface low will track northeastward from the mid Mississippi Valley into the southwestern Great Lakes. Ahead of the surface low, a warm front will move northward through the Ohio Valley. To the south of the warm front, surface dewpoints will be in the upper 60s and lower 70s F. This will enable an axis of instability to develop by afternoon, with MLCAPE likely peaking around 1000 J/kg. Ahead of the trough, a mid-level jet will overspread the warm sector during the afternoon. This will create moderate deep-layer shear over much of the Ohio Valley, which will support isolated supercell development. In addition, RAP forecast soundings in the Ohio Valley by mid afternoon have 0-3 km storm-relative helicity in the 200 to 250 m2/s2 range suggesting that a tornado or two will be possible. Short line segments capable of isolated severe wind gusts will also be possible. Poor lapse rates will be the main limiting factor for a greater severe threat coverage and magnitude. ...Southern Plains... An upper-level trough will move into the Great Plains today, as mid-level flow remains southwesterly ahead of the trough. At the surface, a cold front will advance southward across the southern Plains, with the front located from west-central Texas into southeast Oklahoma by afternoon. Although large-scale ascent will be weak, low-level convergence along and near the front will result in thunderstorm development. Storms will move east-southeastward across a narrow corridor of instability, where MLCAPE is forecast to peak in the 1000 to 1500 J/kg range. As low-level lapse rates steepen in the afternoon, isolated severe wind gusts will be possible with multicells. However, deep-layer shear will be marginal for organized convection, and poor lapse rates will be a major limiting factor. ..Broyles/Chalmers.. 10/15/2026 $$