Supercells Closing in on Southern Wisconsin, Northern Illinois with Imminent Watch — SevereWX

Supercells Closing in on Southern Wisconsin, Northern Illinois with Imminent Watch

An outflow boundary from this morning's storms is lifting north across northern Illinois into southern Wisconsin this afternoon, setting the stage for intensifying severe weather. The SPC's Mesoscale Discussion 1441 highlights ongoing supercells to the west straddling this boundary and tracking east, posing threats of 1-1.75-inch hail, 65-80 mph wind gusts, and a locally higher tornado risk up to 90 mph—especially where storms latch onto the boundary.

Strong heating north of the boundary is fueling northward motion, with storms expected to evolve and potentially spark new development farther east. A downstream watch appears probable by 4 PM CDT (MD valid until 5 PM), or sooner if activity surges along the line. Northern Illinois (including areas near Rockford) and southern Wisconsin (Madison vicinity) are in the crosshairs as these storms push through during peak heating.

Peak Threats:

This setup builds on earlier Iowa activity but focuses on the downstream evolution. Monitor radar closely as WFOs LOT, MKX, DVN, and ARX issue updates.

Stay prepared: Have multiple alert sources (NOAA radio, apps like SevereWX.net), secure outdoor items, and know your safe spot indoors away from windows. Act quickly if warnings are issued near you.