Dear Tom,
Has there ever been a day that no clouds were present in the sky in the whole United States?
Settimo Pollina, Hainsville, Ill.
Dear Settimo,
Records of such events are not kept, but we sampled the opinions of several meteorologists, locally and nationally, in operational and academic settings, and they all concur with our feeling: It does not happen, for a variety of reasons. The United States (Lower 48) is so huge that even the largest cloud-suppressing high pressure systems cannot simultaneously dominate the weather across the entire nation, and cloud-producing moisture is always readily available from the Pacific, Atlantic, Gulf and Great Lakes. Even in otherwise clear weather, mountainous terrain generates clouds when winds blow upslope. Afternoon cumulus clouds always form somewhere, and high-level winds (30,000 feet or more) often carry in cirrus clouds from storms thousands of miles distant.
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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.
Write to: ASK TOM WHY, 2501 Bradley Pl., Chicago, IL 60618 or asktomwhy@wgntv.com (Mail volume precludes personal response.)
WGN-TV meteorologists Steve Kahn, Richard Koeneman and Paul Dailey plus weather producer Bill Snyder contribute to this page.
