Day 1 Convective Outlook
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Summary
An organized threat of severe thunderstorms is expected from eastern Ohio into western New York on Wednesday. Isolated to widespread severe thunderstorms are also possible across the Midwest and central Plains throughout the day.
Product Text
000 ACUS01 KWNS 090543 SWODY1 SPC AC 090541 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1241 AM CDT Wed Sep 09 2026 Valid 091200Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN OHIO INTO WESTERN NEW YORK... ...SUMMARY... Isolated strong to severe thunderstorms are possible across portions of the central Plains to the Ohio Valley on Wednesday. A more organized severe weather threat is expected from eastern Ohio to western New York. ...Synopsis... A belt of enhanced mid-level flow will move through the broad upper-level trough across Ontario, overspreading the Great Lakes into Upstate New York and Quebec. A cold front will extend from a deep surface low across northern Ontario south through the Upper Midwest and into the central High Plains. Isolated to widely scattered thunderstorm activity is expected near the surface trough across the Ohio Valley into the Northeast and along the front from the Midwest to the central High Plains. ...Eastern Ohio into western New York... Across the eastern Ohio Valley into portions of the Northeast, strengthening mid-level flow will overspread the region with thunderstorms developing along the cold front and pre-frontal surface trough. Upper 60s to 70s dew points and filtered daytime heating will yield moderate instability amid ample deep layer shear for organization. Mode will likely be a mix of multi-cell clusters and transient supercells, with potential for damaging wind. Generally weak lapse rate profiles and quick mode transition to clusters/linear segments should limit hail and tornado potential. Nonetheless, as the low-level jet increases into the afternoon and clockwise curvature increases in hodographs a tornado may be possible. ...Ohio Valley to the Midwest and the central Plains... Morning convection will be likely across much of the Midwest/Mid-Missouri Valley into the northwestern Ohio Valley. Remnant shower activity/cloud cover will likely limit severe potential with northern extent. Nonetheless, isolated to widely scattered thunderstorm activity is expected to develop by the afternoon along the front and remnant outflow from the eastern Ohio Valley through portions of the Midwest and into the central Plains. Flow will be fairly weak across the central Plains, with generally a marginal damaging wind threat with multi-cell clusters as daytime heating steepens low-level lapse rates amid deeply mixed profiles. Slightly better flow aloft may favor a more focused cluster across the Mid-Mississippi Valley into western Kentucky/Tennessee. ..Thornton/Chalmers.. 09/09/2026 $$