The intense heat has been blamed for nearly two dozen deaths, including in Missouri, where officials are investigating whether 13 deaths were heat-related, CNN reported. Four heat-related deaths in Oklahoma have been confirmed.
Excessive-heat watches, warnings and heat advisories were in effect in more than 30 states Wednesday, as triple-digit temperatures and tropical-level dew points combined for hot, soupy conditions.
Jeff Hershberger, a spokesman for the Kansas City Health Department, said it would take at least six weeks for officials to process toxicology tests to determine whether all 13 victims died of heat-related causes.
In Oklahoma, the state medical examiner's office said another eight deaths could be heat-related. Triple-digit temperatures are forecast in the eastern United States through Saturday before cooling off slightly to the mid-90s by Sunday, the National Weather Service said.
The peak of the heat wave will be Friday for the major cities of the Northeast, AccuWeather.com said. Highs will soar well into the 90s in Boston and New York, while Philadelphia and Washington could see temperatures topping 100 degrees.
"When all is said and done, with the number of days of extreme heat and humidity of the current heat wave, it may be more significant and impact a larger area than the deadly 1995 heat wave of July 12-15," AccuWeather Senior Meteorologist Jim Andrews said.
The 1995 Chicago heat wave led to approximately 750 heat-related deaths in Chicago during a 5-day period.