Triggered by a warm front, a wide band of showers – possibly including a few isolated thunderstorms – will spread east into northeast Illinois, southeast Wisconsin and northwest Indiana this evening with rain continuing off and on across the Chicago area much of the overnight hours.
Late this afternoon the warm front was located over eastern Nebraska across northern Missouri into southern Illinois. That front will slowly move east across Iowa tonight – at the same time slowly lifting north – probably moving through the Chicago area Thursday morning. Clouds will gradually increase and lower this evening, while winds shift from northeast to east and finally southeast late tonight. Initially this evening dew-points will be in the 20s, and rain falling from the clouds into the dry air will evaporate, but eventually the air will moisten enough for the rain to reach the ground.