A "major heat wave" is expected to affect two-thirds of the American nation through this weekend.
On Tuesday night, an estimated 34 million people were under heat advisories and another 21 million were under excessive heat warnings, according to the weather service. Temperatures are expected to be between 85 and 97 degrees, with the hottest forecast on Saturday. In New York City, temperatures and heat indices are forecast to reach "dangerously high levels by the weekend", with temperatures in the mid- to upper-90s by Friday, with heat indices of close to 107 degrees on Saturday. Cooling centers are set to be open in New York City from Wednesday to Sunday. This heat wave is expected to bring the hottest temperatures so far this year in Chicago, Detroit, New York City and Washington, D.C.
Detroit is expected to see an afternoon heat index of up to 105 degrees Friday and Saturday; Chicago is forecast to get much of the same; and the Washington, D.C. area could see heat indices of up 100 to 115 degrees during the afternoons of Friday through Sunday. In the future, for the years to come, "Florida and southern Florida is looking at the highest increases in the amount of days with killer heat temperatures," said Dr. Juan Declet-Barreto with the Union of Concerned Scientists. "We have found across the USA we could quadruple the number of days with heat index above 105," he also said.