Fox News Weather Center

Reports: Violent thunderstorms threaten northeastern US with flash flooding, isolated tornadoes

A strong storm system over southern Canada is forcing much cooler air from the Midwest to collide with warm, humid air over the northeastern United States.

Locally violent thunderstorms erupting from the Ohio Valley to the eastern Great Lakes region and central Appalachians will pose risks to lives and property into Friday night.

"In addition to the potential for damaging winds, large hail and flash flooding, a few tornadoes can be spawned in this severe weather event," said AccuWeather Senior Meteorologist Alex Sosnowski.

Thousands of customers across the northeastern U.S. are dealing with power outages as severe storms continue to impact the region.

As of 3:50 p.m. EDT Friday, 911 call centers and law enforcement have reported several downed trees in parts of West Virginia, Pennsylvania, Ohio and New York, blocking some roads, causing damage and knocking down power lines. Officials are urging drivers to take caution.

Waterspouts have been spotted over the Great Lakes region as severe storms move through the northeastern US and southern Canada early Friday afternoon. A resident of Crystal Beach, Ontario, filmed a waterspout over Lake Erie, about 6 miles from Buffalo, New York.

(YouTube video/deniskreze)