A persistent weather pattern is bringing unusually hot temperatures to the eastern United States, with forecasters predicting that record high temperatures could be broken Wednesday in major cities including New York, Philadelphia and Washington, D.C.

The heat wave is notable both for its intensity in mid-April and its expected duration, with near-record temperatures forecast to continue through the weekend. The National Weather Service projects a high of 86 degrees for Central Park in New York City on Wednesday, just one degree below the record of 87 set in 1941. Philadelphia could see temperatures reach 92 degrees, while Washington, D.C. may hit 94 degrees and Atlanta could reach 88 degrees.

According to meteorologists, while temperatures approaching 90 degrees in April are not unprecedented, the duration of such a heat wave at this time of year is rarely seen. "That's borderline unprecedented as far as the duration of it this time of year," said John Feerick, a senior meteorologist at AccuWeather.

The unusual weather pattern follows severe storms that struck Kansas, Minnesota and Wisconsin on Monday, with additional storms threatening the nation's midsection on Tuesday. A strong ridge of high pressure is responsible for bringing the hot air mass to the eastern United States, according to the National Weather Service.

Health officials note that early-season heat can be particularly stressful on the human body since people have not yet acclimated to higher temperatures. Heat is the leading weather-related cause of death in the United States, with infants, young children, older adults, people with chronic medical conditions and pregnant women being especially vulnerable.

The heat wave is expected to continue through Friday, with the Weather Prediction Center forecasting widespread temperatures in the lower to middle 90s across the Carolinas that could set additional daily records. Relief is anticipated by Sunday as a strong cold front moves toward the eastern seaboard, bringing cooler conditions by Monday.