NYC may see 4 inches of rain, significant flooding Friday from Ophelia’s remnants: ‘This is a serious storm’

New Yorkers should prepare for significant flooding Friday as the city and the greater tri-state area will be pummeled with up to four inches of rain following a wet and gray week.

The National Weather Service issued a flood watch for the area from 2 a.m. Friday through 6 a.m. Saturday as nonstop rain is expected to drench the five boroughs along with Long Island and parts of New Jersey and Connecticut.

The region is expected to get between two to four inches of rain with some localized areas getting more than five inches, the NWS predicted.

Heavy and fast downpours of more than one inch per hour are also possible — heightening the risk of flash floods and likely affecting New Yorkers’ commutes whether they travel by subway or drive.

“The rain will come in tonight on the lighter side and by tomorrow morning, and through the day tomorrow, we expect a narrower band of really intense rain to set up,” Fox Weather meteorologist Greg Diamond told The Post Thursday.

“We’re looking at more than an inch per hour that could fall and rain this heavy is enough to flood roads and cause flash flooding across the area.”

The rain will begin to lighten up by Friday night but will linger into at least the first half of the day on Saturday, he added.

The downpours are caused by the remnants of what was Tropical Storm Ophelia mixing with converging winds just north, Diamond said.

The Big Apple and surrounding areas have been hit with several days of rain since last weekend which is expected to make the flooding worse.

“The wet days that we had recently are leading to a higher risk for flooding,” Diamond said.

This will particularly be a problem in North Jersey, the meteorologist said.

Some minor coastal flooding is also possible as a supermoon will raise high tide above its normal limits — but the worst of the water will come from the heavy downpours, according to Diamond.

Residents in the affected areas should be cautious of street flooding and expect road closures.

The MTA also warned that the subway system will “inevitably” be impacted by the precipitation. The authority will activate its 24-hour situation room to monitor conditions and make repairs as needed throughout the storm.

“This is a serious storm, and we’re taking it seriously,” MTA Chair and CEO Janno Lieber said in a statement. “We have a detailed plan in place to protect our network and deliver safe service throughout the storm. MTA crews have been deployed at strategic locations so they can respond quickly.”

The transit agency will send out its fleet of emergency response equipment, including trucks, pumps and pump trains to remove water from flooded underground stations and tracks.

Diamond said the forecast evolved quickly and at the last minute — so many people may not be prepared for its severity.

“The weather models had a hard time determining the severity of the event and they didn’t really come online until earlier this morning to show this magnitude of rain so I think a lot of people are going to be caught off guard by it,” he said.