Tornado Caused 'Extensive Damage' In Eastern PA Monday: NWS

This story was last updated at 9:56 p.m. Tuesday.

PENNSYLVANIA— A tornado touched down in eastern Pennsylvania during fierce storms on Monday night, the National Weather Service confirmed.

Storm assessment teams surveyed damage on Tuesday in the Philadelphia and Allentown areas. NWS meteorologists confirmed that a tornado caused "extensive damage" in the Midway Manor section of Allentown.

"The survey team has confirmed that the extensive damage that occurred was due to a tornado," said the weather service.

Downed trees covered lawns and sidewalks on Club Avenue in Allentown on Tuesday morning, according to video posted by CBS Philadelphia's Nikki DeMentri.

Storm surveyors also looked at a storm path moving from Delaware northeast into Pennsylvania, with the area including Chadds Ford and Glen Mills. The survey team there determined that damage "was due to straight line winds," said the NWS.

The initial reports did not say how strong the winds were; the NWS will release more information as the storm surveys continue.

Fierce thunderstorms, with expected gusts of wind up to 70 miles per hour, moved through the region Monday. Several tornado warnings were issued, including in Chester, Delaware, Montgomery, and Philadelphia counties.

Thousands of people were without power in suburban Philadelphia communities Monday night, and the outages persisted into Tuesday: Nearly 22,000 people were without power in Chester County on Tuesday morning, as were thousands more in Marple, Newtown, and Lower Merion Township.