Travel warnings for an area stretching from Vermont and upstate New York to Virginia, Pennsylvania and western Long Island and Connectcut were in effect from 4 to 10 p.m., meteorologist Joe Cioffi said.
Humidity will continue to climb during the day, with isolated downpours possible, he said.
"If you a travelling to a vacation destination it might be easier to go earlier before thunderstorms arrive," Cioffi said.
"I am not forecasting anything catastrophic," he added. "This is simply a matter of thunderstorms threatening the 4 p.m.-10 p.m. time rush."
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