NEW YORK (AP) — Heavy rain swept across parts of the U.S. Northeast on Monday night, inundating sections of New York and New Jersey with flash flooding that stranded vehicles in roadways, closed subway lines and led to a declaration of a state of emergency.

Millions across the Northeast and Mid-Atlantic remain under flash flood warnings early Tuesday as slow-moving summer storms bring heavy showers to the East Coast, impacting transportation and leaving people stranded in vehicles on waterlogged roads.

More than 50 million Americans throughout the Northeast are under flood watches on Monday, with flash flooding causing significant delays to New York City transportation. Flash flood warnings have been issued for cities including New York City,