Flash flood warnings issued as strong thunderstorms dump heavy rain on parts of N.J. (2024)

The National Weather Service has issued flood warnings in several New Jersey counties because of strong thunderstorms that have dumped heavy rain on some areas of the state Tuesday afternoon. The thunderstorms have also prompted ground stops at Newark Liberty International Airport along with John F. Kennedy, LaGuardia and Philadelphia International airports.

One flash flood warning, issued about 3:45 p.m. Tuesday, is effective through 6:15 p.m. and covers central sections of Middlesex County and northeastern sections of Monmouth County, where up to 2 inches of rain had been reported shortly before 4 p.m.

Another flash flood warning, issued shortly before 5 p.m., covers a wide swath of Monmouth County and is effective through 9 p.m., while another warning covers parts of Mercer, Middlesex and Monmouth through 8:15 p.m.

A flash flood warning for parts of New York includes southeastern sections of Bergen County, with that warning continuing through 7:45 p.m. (See the latest flood warnings listed below.)

The weather service said some towns in the flash flood warning zones have been hit with 1 to 3 inches of rain during the past several hours, with another 1 to 2 inches of rain expected tonight.

One of the places hit hard by heavy rain is Oceanport in Monmouth County, where nearly 3 inches of rain fell between 3 p.m. and 5 p.m., according to automated rainfall data from the Rutgers NJ Weather Network. More than 2 inches of rain has been reported in Hopewell in Mercer County.

A resident of Brick Township said parts of Mantoloking Road near the Mantoloking Bridge had heavy flooding at about 4:45 p.m., with more than 10 inches of water reported to be in the roadway.

Another area that was hit hard was Hackensack in Bergen County where the local fire department reported on its X/Twitter account that nearly half the city is flooded and urged travelers to stay away until the water recedes.

In Madison, a borough in Morris County, local officials said on social media that the municipality “took a direct hit” from the storm.

“Flooding, downed trees, utility wires, and power outages are occurring,” borough officials said. “Be assured all essential personnel are working to clean up roadways and restore power as quickly and safely as possible.”

Another Morris County town, Riverdale, also reported flash flooding in the area.

The South Brunswick Police Department asked all motorists around 9 p.m. to limit travel in town as flash flooding was expected.

The storms also began affecting travel Tuesday night as Morris and Essex Line rail service was suspended in both directions between Dover and Summit due to weather-related overhead wire issues as of 7 p.m. Customers were asked to visit http://njtransit.com/ABC for alternate service information.

As of 9 p.m., there was no service between PATCO’s Collingswood & Woodcrest Stations because of flooding in the track area in Haddonfield. Trains were only operating only between 15/16th & Collingswood and between Woodcrest & Lindenwold Stations.

Latest N.J. flood warnings

These are among the latest flood warnings issued in New Jersey, with newer ones listed on top:

More rain threats to linger

Forecasters said strong thunderstorms and heavy rain will continue impacting many areas of the state at times Tuesday evening and Tuesday night and could linger into Wednesday morning because of a frontal system that is expected to stall out over the Mid-Atlantic region. The thunderstorms could pack extra moisture that’s being pushed north from Tropical Storm Debby, which is meandering near the coast of Georgia and South Carolina.

As of Tuesday afternoon, Debby was generating top sustained winds of 40 mph, making it a low-intensity tropical storm. However, it was dumping huge amounts of rain on the southeastern U.S. because the storm was moving extremely slowly. The storm is forecast to linger near northern Georgia and eastern South Carolina through Thursday night before slowly pushing north into central North Carolina and Virginia on Friday.

Debby is forecast to be downgraded to a tropical depression before the storm system reaches New Jersey early Saturday morning. Even though the storm shouldn’t pose a significant danger in terms of wind, it is expected to dump several inches of rain on the New Jersey region.

A flood warning is more urgent than a flood watch, indicating heavy rain that has already fallen or is expected to fall soon could quickly cause water to rise high on local streets and highways, especially near swollen streams and rivers.

Forecasters say drivers and pedestrians should avoid flooded streets and move to higher ground if a flood warning or a flash flood warning is issued.

A flood watch is in effect for 18 of New Jersey’s 21 counties from Tuesday afternoon through Wednesday morning. Only Atlantic, Cape May and Cumberland were not under the flood watch as of late Tuesday afternoon.

Forecasters say the heavy rain could cause rapid flooding on streets in urban areas and in any place with bad drainage systems. Depending on how much rain falls and how long it persists, some rivers, streams and creeks could overflow.

Thank you for relying on us to provide the local weather news you can trust. Please consider supporting NJ.com with a voluntary subscription.

NJ Advance Media staff writer Chris Sheldon contributed to this report.

Len Melisurgo may be reached at LMelisurgo@njadvancemedia.com or on X at @LensReality.