The heat wave that's covering the Midwest is slowly moving eastward, but it will be a few days before people in the central part of the country begin to feel any relief.
A combination of stagnant heat and humidity has lead to some type of heat advisory in more than 30 states. In many cases, temperatures are reaching well into the 90s or even topping 100 degrees, with heat index values well into the triple digits.
Melissa Eland was carrying three water bottles, trying to stay cool, as she walked to class at Indiana University.
"It's killer," she said. "But I got plenty of water so it's not that bad."
The National Weather Service says it is unusual for this kind of oppressive heat to stick around for so long. If it continues through the weekend as forecast, this would be the longest heat wave to hit Indiana in 40 years.
Elevated Power Demand
In the Northeast, temperatures are expected in the mid-90s Thursday and Friday, but forecasters predict the heat index could make it feel more like 105 degrees.
Meteorologist Allan Dunham with the National Weather Service in Taunton, Mass., says the high dew point level, combined with hot temperatures, will drench the North Atlantic states in Florida-like conditions.
"This is going to cover basically all of southern New England, getting up into southern New Hampshire all the way back towards New York and down along the mid-Atlantic seaboard," he said.
Dunham added that seniors, children and people with respiratory problems should take precautions.
Nationwide, Thursday and Friday will be hotter than any time since 1950, says Hartman.
"It's going to mean elevated power demand for an extended period of time for a lot of people," said Travis Hartman, the Energy Weather Manager at MDA Earthstat, which proves forecasts for utilities and other weather-dependent businesses.
Utilities say they're ready for high power demand and widespread electricity shortages or outages are unlikely.
Much of the heat is due to a heat "dome" caused by a huge area of high pressure that's compressing hot, moist air beneath it.
"It's hot no matter what you're doing or where you are," said Tim Prader, a 50-year-old construction worker who was taking a break Tuesday at a job site in St. Louis. Although his huge Caterpillar excavator has air conditioning, he couldn't entirely escape. "When you're done for the day, you're ready to eat, drink and hit the couch."
Kim Kristensen, an in-homecare nurse in Madison, Wis., has been checking in with the elderly.
"The one client that we are really worried about are the elderly population who unfortunately don't have any assistance ... they're very much at risk in this hot weather," she told NPR's Michele Norris.
In Manhattan, N.Y., food-truck operator Tan Vir said heat waves like this one are not good for business.
"People don't go out like they normally go out," he said. "So it does affect business here, about 30 percent."
A few blocks south, Joseph Jackson stood in the middle of Broadway, hawking tickets to tour the Empire State building. He said he stays cool with lots of water.
"That's the best thing to do," he said. "Anything else doesn't help."
While heat domes aren't uncommon, this one is unusual because of its size and duration. It began three days ago and may last seven to 10 days in some locations. And it's moving eastward, with temperatures expected to reach 100 degrees in Washington, D.C., by Thursday.
Cooler Temperatures Next Week
National Oceanic and Atmospheric Administration records show that the United States broke 25 local high records for the date on Monday, including 103 degrees in both Edgemont S.D., and Victoria, Texas.
On Tuesday, it was 102 in Manhattan, Kan., and Valentine, Neb. The mercury rose to 100 in Joplin, Mo., and Rockford, Ill., which tied that city's record for the date set in 1930. And in some cities it will be even hotter Wednesday: Chicago reached 93 degrees Tuesday, with 97 forecast for Wednesday.
No widespread deaths have been reported, but the heat sent dozens of people to hospitals.
As hot air blew over the cooler waters of Lake Michigan on Tuesday, a thick fog shrouded many of Chicago's beaches. Lifeguards had to turn away swimmers because they could not see beyond the water's edge.
In South Dakota, up to 1,500 head of cattle died across the state from the heat. And in eastern Iowa, the scorching sun caused a portion of Interstate 380 to buckle.
A Veterans Affairs hospital in Fargo, N.D., had to reschedule more than 50 surgeries after cooling systems struggled to keep up with the weather. Some floors and other surfaces became wet, potentially compromising the sterile environment needed to operate.
In Detroit, more than 70 schools without air conditioning were to close Wednesday afternoon. Power outages and mechanical problems closed several others.
Relief is on the way. Cooler air should begin moving into the Plains states this weekend, as a strong pool of air from the jet stream begins to push hot air out of the way in the Dakotas and into Minnesota before making its way east.
By Monday, temperatures will drop into the mid-80s in the north. Cities in the East could still be sweltering.
NPR's Joel Rose, Sara Wittmeyer of member station WFIU and Bradley Campbell of member station WRNI contributed to this report, which includes material from The Associated Press