Drizzle and dense fog greet many as Tuesday dawns across the Chicago metro area. It’s the second day ill-timed fog shrouds the area, a development which threatens additional flight delays. By late Monday evening, visibilities had already plummeted to less than a quarter mile from DeKalb to Aurora and DuPage Airport. Fog forms when nighttime cooling or the arrival of cool air from an adjacent area forces temperatures to fall to the dew point—the temperature of saturation. When the temp and dew point match, air holds as much moisture as it can. The relative humidity soars to 100% and fog often forms. An area from roughly I-80 northward is at greatest risk for fog, while areas south, including Kankakee and Rensselaer, Indiana, are in for springlike low 70s. Monday’s 62° high at Northerly Island and 66° at Kankakee were the area’s mildest readings in nearly a week.
--By Tom Skilling, WGN-TV Chief Meteorologist
WGN-TV Chief Meteorologist Tom Skilling and the WGN Weather Center staff provide daily coverage of weather in the Chicago area.
