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.

Parts of New York City and Northern New Jersey were inundated on Monday night as widespread thunderstorms moved through.

The National Weather Service released a flood warning at 9:51 p.m. on Monday in effect until Tuesday at 1 a.m. for Essex, Passaic and Union counties.

Just one day after a fast-moving storm swept through New Jersey, causing dramatic rescues, a home explosion, and multiple deaths, officials have issued both a Flood Watch and Heat Advisory for the region.

Flooding is causing problems on multiple New York City subway lines as torrential rain pummels the Tri-State Area.

Forecasters say some thunderstorm cells have the potential to dump as much as 2 to 3 inches of rain in one hour, posing a risk of rapid flooding.