Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
224 ACUS02 KWNS 071747 SWODY2 SPC AC 071746 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 PM CDT Mon Sep 07 2026 Valid 081200Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE CENTRAL PLAINS TO THE UPPER MIDWEST... ...SUMMARY... Strong to severe storms are possible on Tuesday from the central Plains into the Upper Midwest. ...Central Plains to Upper Midwest... An upper-level shortwave trough currently translating through the northern Rockies will move into the Canadian Prairies and northern Plains on Tuesday. A secondary upper-level feature will translate from the northern Rockies to the northern Plains through the period. South of these features, enhanced mid-to upper-level southwesterly flow will overspread the Mid-Missouri and Upper Mississippi Valleys. At the surface, a low over Manitoba will lift northeastward into Ontario by early Wednesday. A trailing cold front will move eastward across the Upper Midwest while the southern extent of the boundary is forecast to stall over southern Nebraska. Ahead of the front, persistent southerly return flow will maintain a moist warm-sector with weak to moderate instability ahead of the front. Most CAM guidance depicts elevated thunderstorms Tuesday morning across parts of Minnesota and Wisconsin, near the nose of the low-level jet. This early activity will likely pose an initial risk for marginally severe hail and isolated strong wind gusts. Further south, severe potential is expected to gradually increase during the evening ahead of the front across Iowa, eastern Nebraska, and potentially northern Kansas. Deep-layer shear will progressively lessen with southward extent but strong convergence along the stalling boundary should support convective initiation within the moderately unstable boundary-layer. Initial cells will likely have a threat for isolated large hail and strong wind gusts, but are expected to quickly grow upscale into line segments with a greater damaging wind threat later Tuesday evening. ..Bentley.. 09/07/2026 $$