Dear Tom,
Regardless of the weather (stormy or settled), Lake Michigan is rougher in the winter than in the summer. Can you explain why?
Bob Meyer
Dear Bob,
It’s true that a given wind, say 15 knots, will build higher waves in the winter than in the summer. Air and water temperature differences hold the key.
Cold air over warm water (the winter situation) transfers more wind energy to the water than does warm air over cold water (the summer situation).
When cold air blows over warm water, the air warms, lifts off the water and is replaced by stronger winds from above. Strong winds are constantly sinking to the lake surface. In summer, it’s just the opposite. Cool, calm air hugs the water, and strong winds remain aloft.
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Tom Skilling is chief meteorologist at WGN-TV. His forecasts can be seen Monday through Friday on WGN-TV News at noon and 9 p.m.
WGN-TV meteorologists Steve Kahn, Richard Koeneman and Paul Dailey plus weather producer Bill Snyder contribute to this page.
