Heat Blankets Much of U.S.

Heat Wave Ihel Gordello waters down "Show Me More" at the Chagrin Valley Hunter Jumper Classic Thursday, July 18, 2013, in Moreland Hills, Ohio. Temperatures will rise to the 90's in northeast Ohio Thursday with a heat index close to 100. (AP Photo/Tony Dejak)

AP Photo/Tony Dejak

Angel Agostini Angel Agostini cools herself off while watering her lawn and plants at her home on Wednesday, July 17, 2013, in Albany, N.Y. Forecasters warned of potentially dangerous temperatures from Minnesota to Massachusetts, as the nation's largest heat wave of the summer stretched out and stagnated, with relief in many places still days away. (AP Photo/Mike Groll)

AP Photo/Mike Groll

Heat Wave Dogs splash in canine wading pools in Hudson River Park during a heat wave, Tuesday, July 16, 2013 in New York. Forecasts are predicting temperatures in the 90s through Saturday. (AP Photo/Mark Lennihan)

AP Photo/Mark Lennihan

Jim Keith Groundskeeper Jim Keith drinks water while taking a break from painting lines on a football field at the University at Albany on Wednesday, July 17, 2013, in Albany, N.Y. Forecasters warned of potentially dangerous temperatures from Minnesota to Massachusetts, as the nation's largest heat wave of the summer stretched out and stagnated, with relief in many places still days away. (AP Photo/Mike Groll)

AP Photo/Mike Groll

Heat Wave Thomas Grant fans himself with his T-shirt while taking a break from gardening in the Jackie Robinson Community Garden, Wednesday, July 17, 2013, in New York. Humid air made it all feel worse, with heat indexes in some places over 100. Parts of 19 states were under weather advisories. (AP Photo/Kathy Willens)

AP Photo/Kathy Willens

Heat Wave Two young men wade near the base of the fast-falling Minnehaha Falls, Thursday, July 18, 2013 in Minneapolis where temperatures hovered near the mid-90's amid a continuing heat wave which has hit much of Minnesota and other parts of the U.S. Recent heavy rains have added to Minnehaha Creek which feeds the falls. (AP Photo/Jim Mone)

AP Photo/Jim Mone

Heat Wave Amalio Medina sits in front of his un-air conditioned shop in the midday heat, Thursday, July 18, 2013, in Philadelphia. An excessive heat warning is again in effect for the Philadelphia region with highs expected to head up to the high-90s (AP Photo/Matt Rourke)

AP Photo/Matt Rourke

Heat Wave Angel Figueroa, right, stands out side his un-air conditioned shop, while his neighbor Jose Leyes sits in the shade, Thursday, July 18, 2013, in Philadelphia. An excessive heat warning is again in effect for the Philadelphia region with highs expected to head up to the high-90s (AP Photo/Matt Rourke)

AP Photo/Matt Rourke

Heat Wave A kayaker glides across Jordan Lake near Farrington Point in Chapel Hill, N.C., Thursday, July 18, 2013. Hot and humid conditions persist throughout the south as a heat wave grips many parts of the country. (AP Photo/Gerry Broome)

AP Photo/Gerry Broome

Heat Wave Alex Roman, 10, keeps cool in a sprinkler at Fairview Park Wednesday, July 17, 2013, in Cleveland. Forecasters warned of potentially dangerous temperatures from Minnesota to Massachusetts, as the nation's largest heat wave of the summer stretched out and stagnated, with relief in many places still days away. (AP Photo/Tony Dejak)

AP Photo/Tony Dejak

Heat Wave A man washes "Aruba" to cool him down at the Chagrin Valley Hunter Jumper Classic Thursday, July 18, 2013, in Moreland Hills, Ohio. Temperatures will rise to the 90's in northeast Ohio Thursday with a heat index close to 100. (AP Photo/Tony Dejak)

AP Photo/Tony Dejak

"I'm sure it feels like 105," Mayi Molh tweeted on July 15. (Courtesy of @yiyiliz)

Courtesy of @yiyiliz

Heat Wave Frank Hathaway pushes his 9-month-old son, James, down the street under an umbrella in the noontime heat, Wednesday, July 17, 2013 in Barre, Vt. The heat wave continued on Wednesday in Vermont. (AP Photo/Toby Talbot)

AP Photo/Toby Talbot

Mario Caamano Worker Mario Caamano takes a water break from the heat during road construction Thursday, July 18, 2013, in Lambertville, N.J. Forecasters say temperatures in the 90s will combine with humidity to make it feel like 105 degrees in parts of the state Thursday. Experts say the heat poses the biggest threat to the very young, the very old and pets. The National Weather Service expects the heat wave to break in the form of showers and thunderstorms on Saturday. (AP Photo/Mel Evans)

AP Photo/Mel Evans

Heat Wave Corn stalks start to show stress under the sun and heat Wednesday, July 17, 2013, in Farmingdale, Ill. The National Weather Service says daily temperatures are expected to reach highs in the mid to upper 90s throughout the Midwest. (AP Photo/Seth Perlman)

AP Photo/Seth Perlman

APTOPIX Heat Wave House painter Jesus Rubela wipes the sweat from his face while restoring a home in the South Boston neighborhood, Wednesday, July 17, 2013 in Boston. Temperatures in the Boston area reached the 90's, extending a heat wave. (AP Photo/Charles Krupa)

AP Photo/Charles Krupa

Virginia Weather Taejan Gray, 11, of Richmond, Va. shows off his form while jumping into the Randolph Community Pool on Monday, July 15, 2013, trying to beat the heat. Kameron Johnson, 8, was already in the water, below. Sizzling temperatures are moving into the Mid-Atlantic region with temperatures forecast to hit near the century mark later in the week. (AP PHOTO/The Richmond Times-Dispatch, Joe Mahoney)

AP PHOTO/The Richmond Times-Dispatch, Joe Mahoney

Wesley Traeger, Alex Traeger Wesley Traeger, 3, left, and his brother Alex, 5, right, both from Washington DC, run through the water fountains to cool off at the Yards Park, near the Washington Nationals baseball stadium, where temperatures were in the mid-90s on Tuesday, July 16, 2013 in Washington. (AP Photo/Pablo Martinez Monsivais)

AP Photo/Pablo Martinez Monsivais

Heat Wave A man sunbathes in Hudson River Park during a heat wave, Tuesday, July 16, 2013 in New York. Forecasts are predicting temperatures in the 90s through Saturday. (AP Photo/Mark Lennihan)

AP Photo/Mark Lennihan

APTOPIX Heat Wave A man cools off on the shore of Castle Island in the South Boston neighborhood, Wednesday, July 17, 2013 in Boston. Temperatures in the Boston area reached the 90s, extending a heat wave. (AP Photo/Charles Krupa)

AP Photo/Charles Krupa

West Heat Wave Children play in a water fountain in Bertha Henschel Park in Sacramento, Calif., Tuesday, July 2, 2013. Temperatures soared into the triple-digits as a heat wave continues in the west. (AP Photo/Rich Pedroncelli)

AP Photo/Rich Pedroncelli

Heat Wave Youngsters frolic on a raft in Curtis Pond to cool off on Tuesday, July 16, 2013 in Calais, Vt. A heat wave will scorch the Northeast this week, as some of the hottest weather of the summer envelops the region. (AP Photo/Toby Talbot)

AP Photo/Toby Talbot

Heat Wave People keep cool by swimming in the water at the Lower Falls of the Swift River, Tuesday, July 16, 2013 in Albany, N.H. A weeklong heat wave continues to bear down on much of the region. (AP Photo/Jim Cole)

AP Photo/Jim Cole

Heat Wave People keep cool by swimming in the water at the Lower Falls of the Swift River, Tuesday, July 16, 2013 in Albany, N.H. A weeklong heat wave continues to bear down on much of the region. (AP Photo/Jim Cole)

AP Photo/Jim Cole

Heat Wave People keep cool while swimming in the water at the Lower Falls of the Swift River, Tuesday, July 16, 2013 in Albany, N.H. A weeklong heat wave continues to bear down on much of the region. (AP Photo/Jim Cole)

AP Photo/Jim Cole

Heat Wave Pam Clark cuts hay at Dimond Hill farm, Wednesday, July 17, 2013 in Concord, N.H. Clark said they have been waiting for this heat wave to hay the fields. (AP Photo/Jim Cole)

AP Photo/Jim Cole

Heat Wave Minneapolis United soccer team players receive a cool mist spray during a break in their game against a team from Canada in the Schwan's USA Cup International Youth Soccer Tournament Wednesday, July 17, 2013 in Blaine, Minn., as a heat wave continued, sending temperatures into the 90's with high humidity and a heat advisory for the Minneapolis-St. Paul area. The tournament showcases more than 950 teams and 14,000 soccer players from over 20 states and 16 countries. (AP Photo/Jim Mone)

AP Photo/Jim Mone

Heat Wave A woman uses a magazine to fan herself while waiting for the trains at the Barclays subway station, Thursday, July 18, 2013 in New York. A heat advisory remains in effect for the New York metropolitan area. (AP Photo/Mary Altaffer)

AP Photo/Mary Altaffer

Heat Wave Teammates of Minneapolis United soccer team huddle in the shade of an umbrella during their game against a team from Canada in the Schwan's USA Cup International Youth Soccer Tournament Wednesday, July 17, 2013 in Blaine, Minn., as a heat wave continued, sending temperatures into the 90's with high humidity and a heat advisory for the Minneapolis-St. Paul area. The tournament showcases more than 950 teams and 14,000 soccer players from over 20 states and 16 countries. (AP Photo/Jim Mone)

AP Photo/Jim Mone

Heat Wave A Minneapolis United soccer player, right, applies a cold wet towel to cool off during their game against a team from Canada in the Schwan's USA Cup International Yourth Soccer Tournament Wednesday, July 17, 2013 in Blaine, Minn., as a heat wave continued, sending temperatures into the 90's with high humidity and a heat advisory for the Minneapolis-St. Paul area. The tournament showcases more than 950 teams and 14,000 soccer players from over 20 states and 16 countries.(AP Photo/Jim Mone)

AP Photo/Jim Mone

West Heat Wave Las Vegas Tourists watch the Bellagio fountain show during a heat wave Thursday, June 27, 2013 in Las Vegas. (AP Photo/Julie Jacobson)

AP Photo/Julie Jacobson

Heat Wave Two women take refuge from the heat in a fountain at the University at Albany on Wednesday, July 17, 2013, in Albany, N.Y. Forecasters warned of potentially dangerous temperatures from Minnesota to Massachusetts, as the nation's largest heat wave of the summer stretched out and stagnated, with relief in many places still days away. (AP Photo/Mike Groll)

AP Photo/Mike Groll

West Heat Wave Photo Gallery Betty Lu Guapo, 4, cools off in the heat at the Los Angeles Fountain Thursday June 27, 2013 in Los Angeles. California prepared Thursday for a scorching weekend that could see temperatures hit 120 in the deserts as a massive heat wave rolled through the West, authorities said. (AP Photo/Nick Ut)

AP Photo/Nick Ut

Heat Wave Frank Hathaway pushes his 9-month-old son, James, down the street under an umbrella in the noontime heat, Wednesday, July 17, 2013 in Barre, Vt. The heat wave continued on Wednesday in Vermont. (AP Photo/Toby Talbot)

AP Photo/Toby Talbot

Heat Wave Dogs splash in a canine wading pool in Hudson River Park during a heat wave, Tuesday, July 16, 2013 in New York. Forecasts say on Wednesday and Thursday, the heat index could reach 100 degrees in New York. (AP Photo/Mark Lennihan)

AP Photo/Mark Lennihan

Heat Wave With the sun beating down, house painter Jesus Rubela climbs up a ladder while restoring a home in the South Boston neighborhood, Wednesday, July 17, 2013 in Boston. Temperatures in the Boston area reached the 90s, extending a heat wave. (AP Photo/Charles Krupa)

AP Photo/Charles Krupa

Heat Wave Art Phillips, left, sells cold drinks along Ashland Avenue on Chicago's Southside as temperatures climb into the high 90's with the heat index breaking 100, Friday, July 19, 2013, in Chicago. (AP Photo/Charles Rex Arbogast)

AP Photo/Charles Rex Arbogast

Heat Wave A street performer who dresses up as a cartoon character takes a break in the shade from posing for pictures with tourists in New York's Times Square, Friday, July 19, 2013. A punishing heat wave continues to scorch New York, threatening to break heat records and putting a huge strain on the state’s overworked power grid. (AP Photo/Mary Altaffer)

AP Photo/Mary Altaffer

Heat Wave A store employee uses a wet rag on his head to stay cool as he beckons customers into his store on the Fulton Mall Friday, July 19, 2013 in the Brooklyn borough of New York. A punishing heat wave continues to scorch New York, threatening to break heat records and putting a huge strain on the state’s overworked power grid. (AP Photo/Mary Altaffer)

AP Photo/Mary Altaffer

Heat Wave A street vendor adjusts his signs advertising cold water on Canal street in the Chinatown neighborhood of Manhattan, Friday, July 19, 2013. A punishing heat wave continues to scorch New York, threatening to break heat records and putting a huge strain on the state’s overworked power grid. (AP Photo/Mary Altaffer)

AP Photo/Mary Altaffer

weather Marcos Rivera Viruet and his dog Wess cool off from the afternoon heat at the Devil's Pool in Wissahickon Valley Park, Friday, July 19, 2013, in Philadelphia. An excessive heat warning is again in effect for the Philadelphia region with highs expected to head up to the high-90s. (AP Photo/Matt Rourke)

AP Photo/Matt Rourke

weather People cool off from the afternoon heat at the Devil's Pool in Wissahickon Valley Park, Friday, July 19, 2013, in Philadelphia. An excessive heat warning is again in effect for the Philadelphia region with highs expected to head up to the high-90s. (AP Photo/Matt Rourke)

AP Photo/Matt Rourke

Heat Wave Jessie Berman, left, and Alicia Bray, right, both of Windsor Conn. help their dog Chili cool off at Crystal Lake in Ellington Conn on Friday July 19 2013. The fourth heat wave of the summer is blanketing the region with oppressive heat but relief is in sight, cooler temperatures are predicted for early next week. MANDATORY CREDIT(AP Photo/Journal Inquirer, Jared Ramsdell)

AP Photo/Journal Inquirer, Jared Ramsdell

HEAT WAVE Trevor Alan Doss, 3, of Manchester Conn smiles as the fountain comes on spraying cool relief while held by his father Keith, in the water fountain at Henry Park in Vernon, Conn. as temperatures hit the upper 90's Friday afternoon July 19, 2013 as a heat wave grips the northeast, relief is predicted to come Saturday. MANDATORY CREDIT(AP Photo/Journal Inquirer, Jim Michaud)

AP Photo/Journal Inquirer, Jim Michaud

Heat Wave New York A woman sheltering from the sun under an umbrella cools herself with water from a fire hydrant on Canal Street in New York's Chinatown Friday, July 19, 2013. A punishing heat wave continues to scorch New York, threatening to break heat records and putting a huge strain on the state’s overworked power grid. (AP Photo/Jon Gerberg)

AP Photo/Jon Gerberg

weather Tourist shield themselves with umbrellas in front of Independence Hall on Friday, July 19, 2013, in Philadelphia. An excessive heat warning is again in effect for the Philadelphia region. (AP Photo/Matt Rourke)

AP Photo/Matt Rourke

Heat Wave Art Phillips, left, sells cold drinks along Ashland Avenue on Chicago's Southside while his girlfriend, Michelle Dyer fans herself with a ball cap as temperatures climb into the high 90's with the heat index breaking 100, Friday, July 19, 2013, in Chicago. (AP Photo/Charles Rex Arbogast)

AP Photo/Charles Rex Arbogast

Heat Wave New York A crossing guard tries to cool off with a bottle of water while working on a sweltering street in New York's Chinatown, Friday, July 19, 2013. A punishing heat wave continues to scorch New York, threatening to break heat records and putting a huge strain on the state’s overworked power grid. (AP Photo/Jon Gerberg)

AP Photo/Jon Gerberg

Heat Wave New York Vendors, shoppers and pedestrians take shelter from the sun under umbrellas in New York's Chinatown, Friday, July 19, 2013. A punishing heat wave continues to scorch New York, threatening to break heat records and putting a huge strain on the state’s overworked power grid. (AP Photo/Jon Gerberg)

AP Photo/Jon Gerberg

Nyla Schira Nyla Schira, 6, swims through traffic at Firefighters Memorial Pool during a heat wave, Friday, July 19, 2013, in Union City, N.J. Thunderstorms are expected to hit the region Saturday, forcing the heat wave out of the area after a week in which temperatures reached the high 90s. (AP Photo/Julio Cortez)

AP Photo/Julio Cortez

Brianna Sanchez Brianna Sanchez, 10, reacts as water pours over her at Firefighters Memorial Pool during a heat wave, Friday, July 19, 2013, in Union City, N.J. Thunderstorms are expected to hit the region Saturday, forcing the heat wave out of the area after a week in which temperatures reached the high 90s. (AP Photo/Julio Cortez)

AP Photo/Julio Cortez

Heat Wave With the New York City skyline as a backdrop, people bathe at Firefighters Memorial Pool during a heat wave, Friday, July 19, 2013, in Union City, N.J. Thunderstorms are expected to hit the region Saturday, forcing the heat wave out of the area after a week in which temperatures reached the high 90s. (AP Photo/Julio Cortez)

AP Photo/Julio Cortez

Christmas in July at Outside the Box Festival IMAGE DISTRIBUTED FOR OUTSIDE THE BOX PERFORMING ARTS FESTIVAL - Outside the Box, the largest music and arts festival in Massachusetts history, provided relief from the scorching heat to hundreds of children by trucking in a ton of snow to transform Boston Common into a winter wonderland complete with a visit from Santa on Friday, July 19, 2013. For more information, please visit outsidetheboxboston.org (Bizuayehu Tesfaye/AP Images for Regan Communications for Outside the Box Performing Arts Festival/Boston, MA)

Christmas in July at Outside the Box Festival IMAGE DISTRIBUTED FOR OUTSIDE THE BOX PERFORMING ARTS FESTIVAL - Outside the Box, the largest music and arts festival in Massachusetts history, provided relief from the scorching heat to hundreds of children by trucking in a ton of snow to transform Boston Common into a winter wonderland complete with a visit from Santa on Friday, July 19, 2013. For more information, please visit outsidetheboxboston.org (Bizuayehu Tesfaye/AP Images for Regan Communications for Outside the Box Performing Arts Festival/Boston, MA)

Ralph Rosado Ralph Rosado, 52, stands under a fountain as water hits him during a warm day caused by a heat wave, Thursday, July 18, 2013, in Union City, N.J. (AP Photo/Julio Cortez)

AP Photo/Julio Cortez

Javier Soler Javier Soler, 20, of West New York, N.J., flips his head back as water from a fountain runs off his hair during a heat wave, Thursday, July 18, 2013, in Union City, N.J. (AP Photo/Julio Cortez)

AP Photo/Julio Cortez

Heat Wave Brookfield Zoo In this photo provided by the Chicago Zoological Society, Hudson, one of the polar bears at Brookfield Zoo in Brookfield, Ill., enjoys a cool swim Thursday, July 18, 2013, as temperatures climbed into the mid 90s. The National Weather Service says it will feel like 105 degrees across parts of the state Thursday as a heat wave continues to bake Illinois. (AP Photo/Chicago Zoological Society, Jim Schulz)

AP Photo/Chicago Zoological Society, Jim Schulz

Heat Wave Salesman Hyper Rosado cools off in between customers during the afternoon heat at Appliances R Us, Thursday, July 18, 2013, in Philadelphia. An excessive heat warning is again in effect for the Philadelphia region with highs expected to head up to the high-90s (AP Photo/Matt Rourke)

AP Photo/Matt Rourke

Heat Wave Salesmen Hyper Rosado, left, and Lu Pichardo take a moment in between customers next to pallets of air conditioners during the afternoon heat at Appliances R Us, Thursday, July 18, 2013, in Philadelphia. An excessive heat warning is again in effect for the Philadelphia region with highs expected to head up to the high-90s (AP Photo/Matt Rourke)

AP Photo/Matt Rourke

Heat Wave Commuters react to the heat while riding the subway, Thursday, July 18, 2013 in New York. A heat advisory remains in effect for the New York metropolitan area as the temperatures rise into the upper 90s. (AP Photo/Mary Altaffer)

AP Photo/Mary Altaffer

Mario Caamano, Paul Lancha Workers Mario Caamano, right, and Paul Lancha work in the hot sun on road construction Thursday, July 18, 2013, in Lambertville, N.J. Forecasters say temperatures in the 90s will combine with humidity to make it feel like 105 degrees in parts of the state Thursday. Experts say the heat poses the biggest threat to the very young, the very old and pets. (AP Photo/Mel Evans)

AP Photo/Mel Evans

Heatwave NYC Abass Asali squeeze a soaking rag of water onto his head while selling "ice cold" bottled water on Thursday, July 18, 2013 in Harlem, N.Y. An excessive heat warning is again in effect as the city hit the high-90s in a fifth day of a heatwave. (AP Photo/Bebeto Matthews)

AP Photo/Bebeto Matthews

Heat Wave Brookfield Zoo In this photo provided by the Chicago Zoological Society, a 6-month-old sloth bear cub cools off with a frozen treat at Brookfield Zoo in Brookfield, Ill., Thursday, July 18, 2013, as temperatures climbed into the 90s. The National Weather Service says it will feel like 105 degrees across parts of the state Thursday as a heat wave continues to bake Illinois. (AP Photo/Chicago Zoological Society, Jim Schulz)

AP Photo/Chicago Zoological Society, Jim Schulz

Christmas in July at Outside the Box Festival IMAGE DISTRIBUTED FOR OUTSIDE THE BOX PERFORMING ARTS FESTIVAL - Outside the Box, the largest music and arts festival in Massachusetts history, provided relief from the scorching heat to hundreds of children by trucking in a ton of snow to transform Boston Common into a winter wonderland complete with a visit from Santa on Friday, July 19, 2013. For more information, please visit outsidetheboxboston.org (Bizuayehu Tesfaye/AP Images for Regan Communications for Outside the Box Performing Arts Festival/Boston, MA)

Mylo Gomez Mylo Gomez, 6, leaps over a fountain while keeping cool during a heat wave, Thursday, July 18, 2013, in Union City, N.J. (AP Photo/Julio Cortez)

AP Photo/Julio Cortez

Heat Wave Brookfield Zoo In this photo provided by the Chicago Zoological Society, Isis, a 7-year-old African lion, enjoys an ice treat filled with beef bones at the Brookfield Zoo in Brookfield, Ill., Thursday, July 18, 2013, as temperatures climbed into the 90s. The National Weather Service says it will feel like 105 degrees across parts of the state on Thursday as a heat wave continues to bake Illinois. (AP Photo/Chicago Zoological Society, Jim Schulz)

AP Photo/Chicago Zoological Society, Jim Schulz

Heat Wave A bicyclist rides across the Manhattan bridge on Thursday, July 18, 2013, in New York. Temperatures climbed up into the 90's again on Thursday in what has become the largest heat wave of the summer. (AP Photo/Jon Gerberg)

AP Photo/Jon Gerberg

Heat Wave Jameek Delmonte of Brooklyn sells cold water on Atlantic Avenue in front of the Barclays Center on Thursday, July 18, 2013, in the Brooklyn borough of New York. Temperatures climbed up into the 90's again on Thursday in what has become the largest heat wave of the summer. (AP Photo/Jon Gerberg)

AP Photo/Jon Gerberg

Heat Wave Sonja Mason of St. Paul stands beneath one of the water falls at Upper Landing Park to stay cool, Thursday, July 18, 2013 in St. Paul, Minn. The largest heat wave of the summer has stagnated over large regions, bringing sizzling temperatures and little hope of relief without rain, a growing possibility for some hard-hit areas as the weekend approaches. (AP Photo/The Star Tribune, Elizabeth Flores) MANDATORY CREDIT; ST. PAUL PIONEER PRESS OUT; MAGS OUT; TWIN CITIES TV OUT

Heat Wave Tour bus salesman Shariff Davis takes a drink of water on Independence Mall in the heat of the midday on Friday, July 19, 2013, in Philadelphia. An excessive heat warning is again in effect for the Philadelphia region with highs expected to head up to the high-90s (AP Photo/Matt Rourke)

AP Photo/Matt Rourke

weather Tourist shield themselves with umbrellas in front of Independence Hall on Friday, July 19, 2013, in Philadelphia. An excessive heat warning is again in effect for the Philadelphia region. (AP Photo/Matt Rourke)

AP Photo/Matt Rourke