Wisconsin Storms Poised for MCS Upscale with 90 MPH Gusts — SevereWX

Storms flickering across portions of central and northern Wisconsin are showing signs of intensifying, with the Storm Prediction Center eyeing potential upscale growth into a damaging-wind MCS through the overnight hours.

Latest SPC Mesoscale Discussion 1751 flags a complex setup where ongoing convection in a warm-air advection regime is racing toward a corridor of extreme instability—up to 4000 J/kg MLCAPE fueled by steep 7-8 C/km lapse rates over mid-70s dewpoints. Effective shear near 50 knots supports supercell structures that could merge into a bow-echo MCS, carving out a swath of severe winds.

However, challenges loom: Convective inhibition (MLCINH), outflow boundaries, stabilizing lake breezes, and Canadian wildfire smoke could stifle development. CAM guidance like WoFS leans toward the main threat after 06Z, but forecasters are monitoring closely for a possible watch issuance (60% probability) within the next couple hours.

Peak hazards include 75-90 mph wind gusts, 2-3.5 inch hail, and 85-110 mph tornadoes (EF1-EF2). The action spans from central WI northward into western Upper Michigan, impacting areas under WFOs GRB, MQT, and others.

Stay prepared: Enable wireless emergency alerts, monitor radar via apps like RadarLive or SPC site, and have a severe weather plan ready—secure outdoors, seek shelter if storms intensify.