CHICAGO – A dangerous stretch of weather is unfolding across the Midwest this Friday, with severe thunderstorms expected to impact areas from southeastern Iowa to northern Illinois and parts of southern Wisconsin. Chicago and Milwaukee are both in the path of storms capable of producing damaging winds, large hail, and even a few tornadoes.
Tornado threat heightened in parts of Iowa and Illinois
Forecasters at the FOX Forecast Center have raised the tornado risk to a Level 3 out of 5 across southeastern Iowa, including the Quad Cities, extending into far western Illinois. This is the area where conditions are most favorable for tornadic development late Friday evening. Meanwhile, Chicago remains under a Level 2 risk, meaning a few rotating storms could reach the city as the evening progresses.
Supercells expected to spark first round of storms
The first storms are likely to develop by mid-to-late afternoon, forming as isolated supercells across northern Missouri, southern and eastern Iowa, and northern Illinois. These types of storms are notorious for producing large hail and brief tornadoes, especially during the early stages. Cities like Chicago, Rockford, and even parts of southern Wisconsin should be on alert through the early evening hours.
As the sun sets, these storms are expected to merge into larger clusters, spreading east and southeast with increasing risk for widespread damaging wind gusts. Forecast models suggest gusts could exceed 70 mph, enough to knock down trees and power lines.
Heat and humidity fueling the storms
Friday’s atmosphere is loaded with energy. Temperatures in Chicago are topping out near 89°F (32°C), and dew points in the low to mid-70s°F (21–24°C) are making the air feel thick and unstable — perfect fuel for storms. This combination of heat and moisture is creating the ideal setup for strong, fast-developing convection.
Storm threat continues Saturday into the Great Lakes
The risk doesn’t end with Friday. By Saturday, July 12, the focus shifts east into the Great Lakes, including portions of Indiana, Michigan, and northeastern Illinois. The FOX Forecast Center has issued another Level 2 severe weather threat for the day, as a cold front and jet stream disturbance push through the region. Severe storms could once again develop during the afternoon and evening, with the potential for large hail and destructive wind gusts.
Temperatures are expected to stay hot, with readings in the upper 80s to low 90s°F (31–33°C). Combined with the lingering humidity, the environment will remain primed for dangerous storms.
Flash flood risk on the rise
In addition to the severe thunderstorm threat, flash flooding is becoming a growing concern. Repeated rounds of storms — especially those forming in quick succession — are likely to dump heavy rainfall over already saturated ground. A Level 2 out of 4 flash flood risk is now in effect from northern Missouri and Iowa through northern Illinois, including the Chicago metro area.
Some places have already been hit hard. On Thursday, more than 3 inches (76 mm) of rain fell in Rockport, Illinois, triggering a Flash Flood Warning. With more storms lined up for the evening and overnight, forecasters warn that urban flooding and rapidly rising creeks and rivers could become a real issue.
Communities across the region are being urged to stay weather-aware and monitor updates closely as the situation evolves through the weekend.
