662 ACUS03 KWNS 131922 SWODY3 SPC AC 131921 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0221 PM CDT Mon Apr 13 2026 Valid 151200Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PORTION OF THE SOUTHERN PLAINS INTO SOUTHERN WISCONSIN... ...SUMMARY... Severe thunderstorms posing a risk for large hail and strong wind gusts will be possible across portions of the southern Plains toward the Great Lakes on Wednesday afternoon and evening. ...Synopsis... The upper-level trough will move eastward from the Plains into the Upper Midwest on Wednesday, with continued enhanced west to southwesterly flow across the southern Plains into the Great Lakes Region. The surface dryline will remain in a similar location from Tuesday, extending across western Oklahoma into southwestern and western Texas. A surface low will shift eastward across IA into WI, with a cold front shifting south and east through the period. Scattered thunderstorm development is expected from the Southern Plains into the Upper Midwest along the aforementioned boundaries Wednesday afternoon and evening. ...Southern Plains to Great Lakes... Widely scattered showers and thunderstorms will be ongoing at the start of the period at 12z Wednesday across much of the Slight Risk region. A secondary round of thunderstorm development is likely to occur near and ahead of the dryline extending from west Texas into western Oklahoma Wednesday afternoon. It remains somewhat uncertain how morning convection will evolve and what the resulting effect on the thermodynamic environment will be. Most guidance suggests that in the area ahead of the dryline across central OK to the Red River in northern Texas will develop at least moderate instability (1000-2000 J/kg of MLCAPE). Deep layer shear profiles will remain strong favoring supercells as the primary mode. The main threat will be for large to very large hail and damaging wind, given linearly elongated hodographs and weaker low-level shear. Thunderstorms are also expected to re-develop further north across the central Plains into the Great Lakes region along the dryline/cold front intersection. A messy mode with mix of supercells and multi-cell clusters is likely given the eventual southward moving cold front. Similarly, the main risks will be for damaging wind and large hail across these regions. ...Northeast... Shower and thunderstorm activity is expected to develop along and south of a diffuse frontal boundary across the Great Lakes into southern NY/northern PA. Modestly unstable profiles, steepening lapse rates, and strong deep layer shear will allow for some isolated severe storm risk. Primary risk would be for damaging wind and small hail, though, a tornado could be possible near the boundary. ..Thornton.. 04/13/2026 $$