The National Weather Service urged people to avoid travel if a flash flood warning was in place for their area.

In Plainfield, New Jersey, two people were killed when their car was swept into Cedar Brook, city officials said. This comes days after two others were killed in severe storms in Plainfield on July 3.

A state of emergency was declared in New Jersey after slow-moving thunderstorms unloaded a significant amount of rain, resulting in dangerous flash flooding across the Northeast into Monday night. At least 2 were killed.

New York and New Jersey hit by torrential rain and flash floods, forcing highway closures, suspending subway lines and flight delays.

A flash flood warning was in effect in New York City until 9:45 p.m., and New Jersey Gov. Phil Murphy declared a state of emergency. Middlesex, Morris and Somerset counties remained under a flood warning until 7:15 a.m. Tuesday.

On Tuesday at 7:55 p.m. the NWS Raleigh NC released a flash flood warning in effect until 11 p.m. for Forsyth County.

Heavy rains during the evening brought flooding, road closures and power outages throughout New Jersey, which is under a state of emergency.

The Center Valley area in Upper Saucon Township, where flooding was reported along Route 309, had a recorded 6 inches of rainfall, making it the highest rainfall total in the Lehigh Valley, according to the National Weather Service in Mount Holly, New Jersey. Other areas had about 1 or 2 inches of rain.

New Jersey is under a state of emergency after a flash flood caused at least two deaths in Plainfield and damage across Union County.