As the sky clears up today, humidity will move in and could push the heat index to over 100 degrees by Wednesday.

The sun will come out and the high will temperature will reach the low 80s, but humidity will make it feel hotter.

Wednesday will bring a 20% chance of additional rain and a high temperature of 91, but humidity will drive the heat index to as high as 103, said Lee Hendricks, a meteorologist with the National Weather Service in Pittsburgh.

A 40% chance of rain Wednesday night will be followed Thursday by rain and high humidity during the day and the possibility of severe thunderstorms in the evening.