Summer started with a bang Wednesday with a blistering, record-smashing heat wave in the Northeast and Mid-Atlantic, where temperatures soared well into the 90s and hit 100 degrees in a few spots.

Record high temperatures were broken Wednesday in locations such as New York City's LaGuardia Airport (98 degrees), Newark, N.J. (98), Hartford, Conn. (97), and Burlington, Vt. (95 degrees).

Today and Friday should see more record-breaking heat before cooler air arrives in time for the weekend. For the Northeast and Mid-Atlantic, it was the season's first significant heat wave, which can be the most dangerous, said National Weather Service spokesman Chris Vaccaro.

"Early season heat outbreaks can lead to a high number of heat-related health issues," he says, "as our bodies aren't used to it yet." Mail carrier Connie Vincent was already sweating as she began her rounds in Manchester, Conn., Wednesday morning. "There's nothing you can do," she said as she dabbed her face with wet washcloths.

"Tomorrow's my day off, thank God. I've just got to make it through today." The weather service posted heat advisories and warnings in a continuous stretch from central Virginia to southern Maine, a distance of more than 600 miles.

The heat produced some bizarre weather statistics: It was much warmer on Wednesday in Concord, N.H. (96 degrees) than it was in Miami (79 degrees). Some spots in New Jersey neared 100 degrees. At an outdoor high school graduation in North Bergen, N.J., several relatives of graduates were treated for heat exhaustion and taken to a hospital.

The cause of the heat in the East, according to AccuWeather meteorologist Andy Mussoline, was a large high-pressure system that settled over the Mid-Atlantic, bringing in warm air from the South. Heat can build up pretty quickly in the summer under these high-pressure systems, he said. The worst of the heat in the Northeast and Mid-Atlantic should end late Friday, he said, thanks to a cold front that's forecast to move into the region, bringing the chance for showers and thunderstorms.

"Much more comfortable weather will move into the region by the weekend," Mussoline said. The typically torrid desert Southwest was seeing its own heat wave Wednesday, where highs were forecast to reach a scorching 115 degrees, hot even by the standards of that part of the nation. More extreme heat is likely today and Friday in the Southwest.

Excessive heat warnings were posted in southeastern California and southwestern Arizona, where highs of 110 to 115 degrees were again possible through Friday.

While the Northeast will get a reprieve from the heat over the weekend and into early next week, the central and southeastern USA should see some searing heat by next week. "Dallas could see its first 100-degree day of the year next week," Mussoline said.

By Doyle Rice USA TODAY