The Chicago area forecast continues to include thunderstorms this afternoon and evening with severe storms most likely later afternoon/early evening. The National Storm Prediction Center Outlook (see headlined map) has much of northern Illinois under a Slight Risk of severe storms (yellow-shaded) mainly for damaging winds and large hail, with a smaller risk of tornadoes.
Low pressure will move east out of Iowa with warm moist air surging north into Illinois and the associated cold front approaching our area from the west. A band of strong to severe thunderstorms is expected to develop in the warm air in advance of the cold front over eastern Iowa into western Illinois early this afternoon and move into western portions of our area by mid afternoon, reaching Chicago and points east later in the afternoon/early evening.
Low pressure is forecast to pass just to our north around midnight tonight with winds here shifting to the northwest and strengthening, bringing cooler air and showers Wednesday.