A refreshing dose of cooler, drier Canadian air reached O’Hare Airport at 8:30 a.m. Tuesday morning, sweeping south of the region a few hours later. The effects were dramatic: Winds switched to the north, visibility sparkled and humidity began to drop. By afternoon, Chicago was reporting some of the nicest holiday weather in the country.
In the days ahead, this air mass inches eastward, passing Chicago Thursday night, and finally settles in the Southeast as the western extension of the Bermuda high by early next week. In summer, slow-moving Canadian highs tend to warm up, entrain humidity and haze, and eventually become the source of summer heat and humidity. As a result, temperatures and humidity should gradually warm with time. Fresh air with a lake breeze turns warmer and more humid over the weekend, and hot and humid with a chance of thunderstorms early next week.
--By Dennis Haller, WGN-TV Weather Center Meteorologist
WGN-TV Chief Meteorologist Tom Skilling and the WGN Weather Center staff provide daily coverage of weather in the Chicago area.
