TL;DR

The NOAA Storm Prediction Center (SPC) has issued a Slight Risk for severe thunderstorms across portions of the Midwest and Great Lakes today, August 9, 2026. Scattered damaging winds are the primary threat from southern Minnesota and eastern Iowa eastward across northern Illinois, southern Wisconsin, southern Lower Michigan, northwest Ohio, and northern Indiana. Storms will peak this afternoon through evening, with northern Illinois facing the greatest potential for intense activity.

What's driving today's severe weather?

A warm front draped across the Corn Belt this morning is slowly advancing northward into the southwest Great Lakes region. Behind this boundary, an increasingly unstable airmass is developing, fueled by a 40-knot southwesterly low-level jet pumping moisture northward.

Surface dewpoints in the lower to mid-70s°F are spreading into northern portions of Illinois and Indiana, creating ample CAPE—the atmospheric fuel for thunderstorms. According to the SPC's 0737 AM CDT outlook, "adequately strong and vertically veering wind profiles will support 30-40 kt effective shear magnitudes."

Early morning showers and thunderstorms moved eastward from northern Missouri into southern Minnesota and western Wisconsin. While these storms may produce localized hail and wind through midday, the main severe weather window opens this afternoon as the atmosphere recovers and destabilizes south and west of the warm front.

Where is the highest risk today?

The Slight Risk area stretches from southern Minnesota and eastern Iowa eastward across:

  • Northern Illinois
  • Southern Wisconsin
  • Southern Lower Michigan
  • Northwest Ohio
  • Northern Indiana

Within this zone, northern Illinois holds the greatest potential for severe weather later this afternoon through evening. The SPC notes that "it seems the greatest potential for severe will be centered over northern IL later this afternoon through the evening," though considerable uncertainty remains regarding exactly where the most intense thunderstorm clusters will develop.

Cities in the risk area include Chicago, Milwaukee, Des Moines, Cedar Rapids, Indianapolis, Fort Wayne, and Toledo.

When will the storms hit?

Morning through midday: A corridor of showers and thunderstorms will continue shifting eastward across the Mississippi River toward Lake Michigan. Localized hail and wind may accompany this activity.

Afternoon and evening: The main severe weather window opens as the atmosphere destabilizes. Expect thunderstorm development over northern Illinois and adjacent areas, with activity continuing into the evening hours. The SPC forecasts storms capable of producing damaging winds as the primary hazard.

Overnight: Severe potential diminishes after dark, though isolated strong storms may persist into the late evening.

What hazards to expect

Damaging winds are the primary threat today. Scattered wind gusts capable of downing trees and power lines are expected across the Slight Risk area. Yesterday's severe weather across 29 states produced 164 wind reports, demonstrating the active pattern currently in place.

Large hail is a secondary concern, particularly with any supercells that develop in favorable environments near the warm front. Low-level storm-relative helicity may be locally enhanced along the effective boundary, supporting organized storm structures.

Tornadoes are not emphasized in today's outlook, though the SPC notes that low-level wind shear could be boosted near the warm front if supercells or linear segments favorably interact with the boundary.

Other areas to watch

Dakotas and western Nebraska

A surface front pushing southward across the central Plains will support scattered severe storms capable of large hail and damaging winds. The SPC outlook states that "supercell wind profiles and steep low-level lapse rates will support initial storms capable of large hail and severe gusts, especially as this activity over the western Dakotas moves southeastward into richer moisture."

A small cluster of storms may evolve overnight with continued severe potential.

Southern Appalachians

Scattered thunderstorms over higher terrain may produce locally strong wind gusts from wet microbursts through early evening within a seasonally moist and unstable airmass.

Arizona

Another day of monsoon activity is expected, with storms developing over higher terrain and spreading westward. Strong outflow gusts are possible as convection moves off the mountains.

Forecast uncertainty

The SPC emphasizes considerable uncertainty in today's forecast for the Midwest. Morning convection and associated outflow boundaries will influence how the atmosphere recovers this afternoon. Model guidance showed poor agreement on where the most intense thunderstorm clusters will ultimately develop.

This uncertainty means the severe risk area and probability levels may need spatial refinements as the day progresses. Monitor updates from the SPC throughout the afternoon—outlooks are issued at 1630Z (11:30 AM CDT) and 20Z (3:00 PM CDT).

What you should do

If you're in the Slight Risk area:

  • Monitor weather conditions through the afternoon and evening. Conditions can change quickly.
  • Have multiple ways to receive warnings. Outdoor sirens may not be audible indoors. Third-party weather apps are silenced by Do Not Disturb, though Wireless Emergency Alerts for tornado warnings still break through on most phones by default.
  • Secure outdoor objects that could become projectiles in strong winds.
  • Identify your safe place now—an interior room on the lowest floor, away from windows.
  • Delay outdoor activities if storms approach. Lightning kills more people than tornadoes in an average year.

If a severe thunderstorm warning is issued for your location, move to your safe place immediately. Damaging winds can arrive with little warning, and most wind-related injuries occur from falling trees and flying debris.

Tomorrow's outlook

The SPC Day 2 outlook maintains a Slight Risk across portions of the Northern Plains, Midwest, and Great Lakes for Monday, August 10. Nebraska, South Dakota, Iowa, Illinois, Indiana, Ohio, and Pennsylvania are included in the risk area as the active weather pattern continues.

VORTEX is a free web app at vortexintel.app that monitors severe weather nationwide. Pro ($4.99/month) places phone calls to your phone when a tornado or flash flood warning is issued for a location you care about — calls can ring through Do Not Disturb once you enable Emergency Bypass for the number, unlike most third-party app notifications.