Flash flood threat as storms hit the Northeast

More than 50 million Americans throughout the Northeast are under flood watches on Monday, with a significant risk of flash flooding in some areas.

Flash flood warnings have been issued for cities including New York City, Washington, D.C., Baltimore, Newark, New Jersey, and Arlington, Virginia — including the Reagan National Airport — through Monday evening.

Life-threatening flooding was possible in western Union County, New Jersey, the National Weather Service warned.

Bergen County in northeastern New Jersey and Westchester County in New York are also under a flash flood warning.

New Jersey Gov. Phil Murphy declared a state of emergency due to the flash flooding and “high levels of rainfall in parts of the state.”

“Please stay indoors and avoid unnecessary travel,” he said on X.

Slow-moving storms are expected to drop a lot of rain quickly. Rainfall rates up to 3 to 4 inches per hour are possible.

Up to 5 inches of rain has already fallen in parts of northern and central Jersey.

Vehicles stranded due to flash flooding have been reported in areas including Union County, New Jersey, and Westchester County.

Widespread flash flooding was also reported in Lancaster County in southern Pennsylvania after heavy rain moved through the area earlier Monday.

This is a developing story. Please check back for updates.