(CBS News) NEW YORK - On Tuesday, America was one nation under a blazing sun. There were red-hot temperatures from coast to coast. The high in Boston hit 93. Washington and New York both hit 95. It was 96 degrees in Baltimore.
The National Weather Service put out a heat alert that stretches from New York to Boston. Three straight days of 90-plus temperatures in New York makes it an official heat wave -- but still far from the record of 12 straight days, back in 1953.
The oppressive humidity means there is little relief, even when the sun goes down. That keeps demand for power high well into the evening hours.
The temperature felt like 104 degrees above ground. And below, it wasn't much better.
"The heat, there's no way to escape it," said Tyrone Barnett, a street musician playing in the New York City subway. "It's just there. You gotta deal with it. You gotta tough through it."
The city's largest power company, Consolidated Edison, has activated its emergency command center to handle what could be record-breaking demand for power.
"We are all on 12 hour shifts through the weekend to make sure whatever comes our way we can deal with, said John Miksad of the Con Ed Command Center in New York City.
Miksad is in charge of the center, where electricity is constantly monitored. He estimates nearly six million air conditioners are running at full power.
"We have not broken any records, but later in the week we are expecting to," he said. "In our history, (it was) something like 13,200 megawatts sometime, probably 5 o'clock on Thursday."
Con Ed has already arranged for power to be supplied from upstate New York or New Jersey, if needed.
Across the Northeast, other utilities have made their own arrangements to meet demand, including asking customers to conserve electricity.
"So far so good right now, but certainly have our eye out for the rest of the week," Miksad said.
Con Ed spent half a billion dollars repairing damage from Superstorm Sandy last fall. That work was just completed in June, and the heat wave is the first real test of those repairs.
Residents in suburban Washington, D.C. are also worried about a water shortage.
A water main in Prince Georges County, Maryland is being shut down for repairs for three to five days. As many as 200,000 people could be affected.
CBS News correspondent Chip Reid reports the many aren't happy the water is being cut off when temperatures are in the 90s, but people doing the work say its urgent business because the pipe is so fragile, it could explode like a bomb at any moment.
Resident Sondra Maith and her 79-year-old father Luther, who's had problems with his kidneys and multiple bouts with cancer, told Reid they are storing water everywhere they can.
Her biggest concern is that her father "gets enough water, because he drinks plenty of water. At least seven bottles a day. And he has to have it for health reasons," she said.
Fire officials are making contingency plans, Reid reports; they're bringing in additional water tankers and even identifying nearby swimming pools as sources for water in case of emergency.
© 2013 CBS Interactive Inc. All Rights Reserved.