Dangerous heat and humidity will extend through the weekend. Daily heat index values will range between 100-110° F. Stay cool. Respect the heat. And don't push it too hard out there.
Common sense ways to beat the heat. Hang in there. A big pattern change by the middle of next week will bring significantly cooler and less humid conditions.
Gusty thunderstorm winds (50-60 mph) and torrential downpours (1"/hr) are the potential hazards with any storm that may develop this evening across portions of central and northern Illinois. Main timeframe to watch is between 5pm and Midnight.