Weather balloon releases — tracking temperature, pressure and wind speed — have been suspended or reduced in the Midwest and Great Plains.

National Weather Service officials are expecting Wednesday waves of showers and thunderstorms to hit the Chicago area capable of producing damaging winds and large hail and possibly tornadoes.

An AccuWeather Alert has been issued for Wednesday, when the entire Chicago area will be under a Level 3 risk for severe weather.

Hurricane-force winds were also reported in parts of the area. Wind gusts topped out at 81 mph in Valparaiso, Indiana, 75 mph in Lakes of the Four Seasons in Indiana, and 74 mph in Gary, Indiana, and Lynwood, Illinois.

A tornado warning was issued in northwest Indiana and most Chicago-area counties saw severe thunderstorm warnings on an eventful Sunday afternoon.

Nearly 68,500 customers are without power as of 10:50 p.m. after another tornado watch was issued for Marion County. This time the outages hit areas in southern portions of Indianapolis, including clusters in Fountain Square, Whispering Pines and University Heights.

Hail and massive wind gusts pelted the Chicago area as severe thunderstorms rumbled through Sunday afternoon. The system had prompted a tornado watch covering most of northeastern Illinois and northwest Indiana, but the National Weather Service canceled it by 3:15 p.m. with storms rolling out over Lake Michigan.

Several states in the central U.S. were hit hard overnight by a deadly storm that reportedly caused flash flooding and even destructive tornadoes.