(Reuters) - Severe thunderstorms unleashed heavy rain and strong winds across parts of the Midwest and Northeast on Thursday, delaying hundreds of flights and leaving tens of thousands of people without power.
The storms spawned a tornado that touched down in Elmira, New York, damaging a mall and a local country club, the National Weather Service said.
There were no immediate reports of serious injuries.
New York Governor Andrew Cuomo said in a statement that the storms knocked out power for nearly 20,000 utility customers.
The storms formed along a cold front stretching from the Northeast into the Ohio Valley and threatened widespread damaging winds, hail and tornadoes, according to the Weather Channel.
Flight delays were reported at airports in Baltimore, Boston, Chicago, New York City, Philadelphia and Washington D.C., the Federal Aviation Administration said on its website.
A severe thunderstorm watch was issued for portions of Indiana, Kentucky, Maryland, New York, Ohio, Pennsylvania and West Virginia.
The National Weather Service's Storm Prediction Center warned that "hail (up) to 2 inches in diameter, thunderstorm wind gusts to 80 miles per hour and dangerous lightning are possible in these areas."
A line of thunderstorms that swept through Westchester County, north of New York City, toppled trees and caused power outages.
Trees that fell across the tracks of the Metro North commuter rail system's Harlem Line brought train traffic to a halt on the line north of Chappaqua, the town that is home to former U.S. President Bill Clinton and U.S. Secretary of State Hilary Clinton.
(Reporting by Kevin Gray; Additional reporting by Dan Burns; Editing by Stacey Joyce)
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