First 90 degree here in a week - but overall summer 90s down 20 percent
The Chicago area flirts with 90 degrees Tuesday for the first time in a week and only the sixth time this month. By almost every measure, meteorological summer 2007 has been a warm one. With just 4 days left in August and the meteorological summer season set to close at midnight this Friday, readings are running 1.7 degrees above normal, daily temperature averages have finished above normal 53 of the past 87 days (61% of the time) and overall air conditioning usage is estimated to have increased nearly 20%. Yet, despite all these warm weather indicators, the number of days at or above 90 degrees is actually off long term averages by 20%. A 91 degree high today marks the 17th 90 degree+ day this year—20 is considered normal.
At 3:30 p.m. on this date 17 years ago, the most powerful U.S. tornado to occur in August formed near Oswego and began a deadly 16.4 mile rampage through Crest Hill and Plainfield. By the time it had dissipated, 29 people were dead and more than 300 injured.
--By Tom Skilling, WGN-TV Chief Meteorologist