Severe flash flooding reported in parts of NJ from nor'easter as warning remains in effect

7:30 a.m. update: This story has been updated to reflect overnight flooding and additional flash flood warnings this morning. 

Severe flash flooding is occurring in northern Monmouth County this morning, National Weather Service Mount Holly said. 

NWS has warned drivers to not travel on any flooded roadways. 

Routes 35 and 36 are both closed in Keyport and Hazlet, as flooding has become significant and first responders are working to rescue multiple cars trapped in the water, according to police reports. 

In Brick, Princeton Ave. was closed this morning in the area of East Drive due to localized flooding, police reports said. 

At least one vehicle was trapped in the water on Princeton Ave. around 6:30 a.m., when authorities blocked it off. 

Rainfall totals:NJ Nor'easter dumped four inches of rain in Monmouth, Ocean counties, and more is coming

11 p.m. update: This story has been updated to reflect increased rainfall projections, particularly over such areas as the Jersey Shore. The story has been revised throughout to reflect the update and Gov. Phil Murphy's emergency declaration ahead of the storm.

Up to 6 inches of heavy rain may potentially fall across multiple areas of New Jersey in the next 48 hours due to a nor'easter storm approaching, as 17 counties are already under a flash flood watch.

Anywhere from 3 to 4 inches of heavy rainfall is expected across most of northern and parts of southern New Jersey, while parts of Burlington, Monmouth and Ocean counties may see up to 6 inches of rainfall, according to the weather service.

Gov. Phil Murphy declared a state of emergency that went into effect at 8 p.m. on Monday.

"The potential for heavy rain has increased," the weather service said in its last briefing early Monday evening. "The possibility of gale force winds on the coastal waters is also high. However, there remains more uncertainty about the threat of damaging wind gusts and minor tidal flooding."

Aside from Camden, Cumberland, Gloucester and Salem counties, nearly the entire state will be under a flash flood watch that will begin at 8 p.m. Monday and last through Tuesday afternoon, according to the latest advisory from the National Weather Service.

Previous forecast: Coastal storm to bring high winds, flooding to central, northern New Jersey

Severe to damaging winds will also play a factor from the upcoming storm, which could result in widespread power outages and downed trees, the weather service said. The strongest winds could range from 15 to 25 mph with gusts as high as 45 mph across the Jersey Shore. 

Gale-force winds are likely along the coast overnight Monday into Tuesday, while minor to moderate coastal flooding is also expected to affect areas across the Jersey Shore, the weather service said.

A low pressure system will approach the state's coastline sometime Monday night with increasing cloud cover followed by heavy showers and severe thunderstorms developing in the overnight hours, according to private meteorologist Steven DiMartino, who runs NY NJ PA Weather.

"Quite a dreary day is expected on Tuesday, as a strong area of low pressure will be parked off the New Jersey coastline," DiMartino said. "Waves of rain will sit over the area and bring rainfall amounts of 1 to 4 inches with locally higher amounts."

The storm could lead to instances of flash flooding around creeks, streams, urban locations and poor drainage areas.

Areas across eastern Monmouth, as well as most of Burlington and Ocean counties are vulnerable to the heaviest amounts of rain and flash flooding on Tuesday, the weather service said.

"Uncertainty remains fairly high with this system," meteorologists wrote in a Monday briefing posted to the weather service's website. "In particular, a small shift in storm track could lead to a considerably greater risk for strong winds and coastal flooding. The location of heaviest rainfall is also subject to some change."

If the storm continues to track toward the Shore, more rain is expected, but if the system heads further south, rain totals are expected to fall, according to the weather service.

Tuesday's temperatures were expected to be in the low 60s to high 50s, after a period of heavy rains.

Joshua Chung is the 9-5 breaking news and weather reporter. A lifelong Jersey Shore resident, he is a recent graduate of Michigan State University. Contact him at jchung@gannettnj.com, 917-703-9373 or on Twitter @Joshchunggg