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Girls leap through a wall of water at Yards Park in Washington, on Thursday, June 21, 2012. Heat index values are expected to exceed 100 degrees across the northeast on Thursday, according to the National Weather Service. (AP Photo/Jacquelyn Martin)

Northeast heat wave

The second day of a heat wave blanketed the U.S. mid-Atlantic and Northeast on Thursday, June 21, sparking power cuts in New York City and forcing utilities across the region to ask customers to conserve electricity.