The high temperature has hit 90-plus for the third consecutive day in Philadelphia, meeting the government criterion for a "heat wave" for the first time in 2012.
At noon, the reading at International Airport was 92, after back-to-back daytime highs of 97.
Meanwhile, the winds of change are approaching. A severe thunderstorm is pounding Long Beach Island, and convection has been firing up elsewhere.
The National Weather Service says that some of the downdraft winds could gust past 40 m.p.h. once the storms start firing up.