'Significant damage' after possible tornado in Delaware as severe storms roil Northeast

Flash flooding is possible from Virginia up to Connecticut.

Authorities in Delaware said there is "significant damage" throughout parts of the city of Dover after a "likely" tornado touched down Thursday evening, including numerous downed trees, flooding and other damage.

The Dover Police Department, in a social media post, said a state of emergency was in effect and asked the public to stay off the roads.

Earlier, the National Weather Service issued a tornado warning for the Dover area, warning of a confirmed large and dangerous tornado on the ground.

It came amid a wave of severe weather that slammed parts of the Interstate 95 corridor during the Thursday evening rush hour, with thunderstorms and dangerous flash flooding

There was a significant risk for flash flooding in New York City, where rain inundated some roadways and subway stations, leading to delays, as well as Philadelphia. Overall, there was the potential for rainfall rates of 2 to 3 inches per hour and 3 to 7 inches of rain in just a matter of hours.

In Pennsylvania, Gov. Josh Shapiro said state emergency management officials were tracking reports of tornadoes and "significant damage in York and Lancaster counties."

Flight cancellations began piling up at Northeast airports, with more than 700 flights canceled as of about 6:30 p.m.

Flash flooding was possible from Virginia up to Connecticut. A flood watch is in effect from Philadelphia to New York City until 2 a.m. Friday.