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The potentially dangerous heat comes after , and more storms threaten Tuesday in the nation’s midsection.

While it's not unprecedented to see high temperatures climb toward 90 degrees (32 Celsius) on an April day, the length of such an April heat wave is rarely seen, experts say.

“That’s borderline unprecedented as far as the duration of it this time of year,” said John Feerick, senior meteorologist at the forecasting firm .

Feerick said that starting Wednesday “we're going to have records challenged from basically Georgia all the way up through the New York City area and back towards the Ohio Valley.�

The National Weather Service is projecting a high temperature around 86 degrees (30 Celsius) for Central Park in New York City on Wednesday. The record high for the date is 87, which has stood since 1941.

Even hotter weather is expected in Philadelphia, where Wednesday's high is expected to be 92 degrees (33.3 C). Other likely hot spots include Washington, D.C., which could see a high of 94 (34.4 C); and Atlanta, where the high is projected to be 88 (31.1 C).

"It's really some very impressive heat for the middle of April, for sure," Feerick said.

“The good thing about this is that the humidity is not summer-time levels,� he added. That means it won't feel as hot as a sizzling July day.

However, the early-season heat can be more stressful on people's bodies since they haven't had a chance to acclimate.

"It's kind of one of those things where it’s a little more stressful to the body because you're not used to it the first time around," Feerick said.

Heat is , the weather service warns. Infants and young children; older adults, people with chronic medical conditions and pregnant women are especially vulnerable to heat-related injuries and death.

A strong ridge of high pressure fueling moisture into the southern plains was responsible for bringing the unusual heat to the eastern U.S., the weather service said.

Though Wednesday is a day when many records could fall, the heat wave will continue through Friday in many areas, forecasters said.

“Widespread lower to even middle 90s are expected Friday across the lower elevations of the Carolinas, which could set additional daily records and perhaps come close to some monthly records,� the agency's Weather Prediction Center wrote in a memo.

The heat wave should finally be breaking down by Sunday as a strong cold front moves toward the eastern seaboard, and then it should be “pleasantly cooler� by Monday with the front heading out to sea, the weather service said.