U.S. heat wave continues, shifts east

By Dr. Jeff Masters

Another day of dangerous heat in the Midwest
The dangerous Central U.S. heat wave of July 2011 will continue to bring another day of exceptionally humid heat to the Midwest today, and will also begin bringing temperatures in the mid-90s with high humidity to much of the mid-Atlantic and New England. The heat index--how hot the air feels when factoring in both the temperature and the humidity--exceeded 100°F in sixteen states in the center of the country on Tuesday, with the dangerous heat extending from Texas northwards to North Dakota, Minnesota, and Wisconsin. At least thirteen deaths are being blamed on the heat in the Midwest. The heat index hit a torrid 129°F at Newton, Iowa on Tuesday, and a heat index in excess of 120° was recorded at several locations in North Dakota, Iowa, Illinois, and Minnesota.

Heat wave headed to the Eastern U.S.
The extreme heat will shift slowly eastwards this week, peaking in Chicago today, Detroit and Pittsburgh on Thursday, and New York City and the mid-Atlantic states on Friday. The forecast high of 103° in Washington D.C. for Friday is just 3° below the hottest temperature ever recorded in the city, 106°. This will no doubt stimulate some predictable quotes on global warming. The heat will remain in place over the mid-Atlantic states through Sunday, then ease on Monday when a cold front is expected to pass through. Wunderground's climate change blogger Dr. Ricky Rood has some good insights on the current heat wave in his latest post.

Predicted maximum heat index for Friday, July 22, 2011. Portions of 35 states are predicted to have a heat index in excess of 100°, with a heat index in excess of 115° expected over large portions of Virginia, Maryland, and Delaware. Image credit: NOAA.

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