Heat Wave

Washington Nationals first baseman Adam LaRoche uses a wet towel on his head to cool off in the dugout during a baseball game against the Colorado Rockies on Saturday, July 7, 2012 in Washington. The Nationals won 4-1. (AP Photo/Alex Brandon)

A fan wears a towel over his head during a baseball game between the Washington Nationals and the Colorado Rockies on Saturday, July 7, 2012, in Washington. The Nationals won 4-1. (AP Photo/Alex Brandon)

Nia Bailey, 8, of Washington, left, and Amari Swint, 8, of Philadelphia, throw water balloons while in an inflatable pool during a seventh annual block party on Newton Street in northwest Washington, during record heat with temperatures in the triple digits, Saturday, July 7, 2012. (AP Photo/Jacquelyn Martin)

Tracy Canty, of Washington, wears a towel over his head against the sun and heat while cleaning off a grill in Washington, during record heat with temperatures in the triple digits, Saturday, July 7, 2012. (AP Photo/Jacquelyn Martin)

Holding a fan, Sandra Bears, left, dances along with Tracy Canty, center, and Tony Crowder, all of Washington, during a seventh annual block party on Newton Street in northwest Washington, during record heat with temperatures in the triple digits, Saturday, July 7, 2012. (AP Photo/Jacquelyn Martin)

De-Ashia Buchanan, 7, of Washington, leans back in a inflated pool during the seventh annual block party on Newton Street in northwest Washington, during record heat with temperatures in the triple digits, on Saturday, July 7, 2012. (AP Photo/Jacquelyn Martin)

Sophie, 3, from Connecticut, frolics with a water sprinkler set up at the National Mall near the Lincoln Memorial, rear, in Washington Saturday, July 7, 2012. The heat gripping much of the country is set to peak Saturday in many places, including some Northeast cities, where temperatures close to or surpassing 100 degrees are expected. (AP Photo/Manuel Balce Ceneta)

Visitors get much needed relief from a water sprinkler set up at the National Mall near the Lincoln Memorial, rear, in Washington Saturday, July 7, 2012. The heat gripping much of the country is set to peak Saturday in many places, including some Northeast cities, where temperatures close to or surpassing 100 degrees are expected. (AP Photo/Manuel Balce Ceneta)

Frank Moralez sells cold beverages to motorists on the Roosevelt Boulevard, Saturday, July 7, 2012, in the Feltonville section of Philadelphia. Temperatures of more than 100 degrees were forecast in Philadelphia and excessive heat warnings were issued for several states in the Midwest as a heat wave continued. (AP Photo/Joseph Kaczmarek)

Avery Gass, 4, slips her way through streams of cooling water, Friday, July 6, 2012, at the Thorton Murphy Park splash pad in Spokane, Wash. The National Weather Service says the high pressure system responsible for heat in much of the country is building into the Northwest this weekend. (AP Photo/The Spokesman-Review, Dan Pelle)

Mikel Welch, 9, floats on his back as he cools off in a fountain Friday, July 6, 2012, in St. Louis. Excessive-heat warnings remained in place Friday for all of Iowa, Indiana and Illinois as well as much of Wisconsin, Michigan, Missouri, Ohio and Kentucky. (AP Photo/Jeff Roberson)

Birds try to deal with triple digit temperatures by panting with open beaks at the Henry Doorly Zoo in Omaha, Neb., Friday, July 6, 2012. The National Weather Service said the record-breaking heat that has baked the nation’s midsection for several days was slowly moving into the mid-Atlantic states and Northeast. (AP Photo/Nati Harnik)

A sleepy jaguar yawns as she prepares for a nap in the heat at the Montgomery Zoo in Montgomery, Ala., Friday, July 6, 2012. (AP Photo/Dave Martin)

Six-year-old Alexander Merrill of Sioux Falls, S.D., cools off in a cloud of mist at the Henry Doorly Zoo in Omaha, Neb., Friday, July 6, 2012, as temperatures reached triple digits. The National Weather Service reported late Thursday that the record-breaking heat that has baked the nation's midsection for several days was slowly moving into the mid-Atlantic states and Northeast. That forecast followed excessive-heat warnings Thursday for all of Illinois and Indiana, as well as parts of Iowa, Minnesota, Wisconsin, Missouri, Kentucky, Ohio and Michigan.(AP Photo/Nati Harnik)

Ethan Pastore, front left, and his brother Evan swim their family's pool Thursday, June 5, 2012, at their home near Lafayette, Ind. Extreme heat continues in the Lafayette area for the second day in a row with temperatures exceeding 100 degrees. (AP Photo/Journal & Courier, Michael Heinz)