The storms struck Thursday, and at one point that evening, severe thunderstorm watches were in effect for a continuous stretch from Oklahoma through New Jersey.
A 61-year-old man in Brooklyn, New York, died after lightning struck a church, sending a scaffold crashing down on him Thursday, authorities said.
Witnesses reported trees in the region buckling under the severe weather's impact.
"The trees were bending sideways, (and) the sky just went really dark and green," said Mark Ventrini, a photographer, as he headed toward Belmar, New Jersey. "Some of the storms were pretty intense."
The National Weather Service had received reports of possible tornadoes touching down in Elmira, New York, and in Brookville, Pennsylvania.
Emergency managers in Broome County, New York, reported people trapped inside a home because of downed trees in the town of Vestal.
Strong storms also caused damage in Binghamton, New York, but the weather service said no injuries or fatalities have been reported there.
There were also extensive power outages. More than 100,000 First Energy customers in Pennsylvania didn't have electricity Thursday night, while other utilities such as PECO and PPL reported tens of thousands of others similarly in the dark.
New York Gov. Andrew Cuomo issued a news release stating there were nearly 95,000 customers without power in that state, mostly NYSEG and Central Hudson customers.
Cuomo also declared a state of emergency for hard-hit Chemung County in the southwestern part of the state.
"The brunt of the storm itself was intense but short -- there was very strong rain and wind for about 15 minutes, at which point the rain cleared and the lightning show began," said Matthew Burke, a CNN iReporter who photographed lightning sprawling across the New York City skyline.