Chicago Thunderstorms Eye Large Hail, Damaging Gusts Late Tonight — SevereWX

Thunderstorms are sparking along a subtle low-level confluence band in northeast Illinois, just ahead of an outflow boundary pushing in from the west. SPC's Mesoscale Discussion 1456 highlights a risk of large hail up to 1.25 inches and damaging wind gusts of 55-70 mph through around 12:45 AM CDT.

Recent observations, including an ACARS sounding near Midway Airport, show a buoyant but modestly sheared environment over the Chicago area. Stronger mid-level flow (around 40 knots) is arriving from upstream, boosting potential for storm organization. Convection could evolve into clusters, with a supercell or two possible along or behind the boundary.

Coverage and intensity remain key watches—guidance struggles with this setup, and storms might weaken nearing Lake Michigan. But if trends sharpen, a tornado watch carries 40% odds.

This threatens the greater Chicago region into extreme southeast Wisconsin late tonight. Monitor radar closely as storms develop.

Stay prepared: Have multiple alert sources, secure outdoor items, and know your safe spot for severe weather. Check SPC for updates.