Flood warnings into Saturday and more swimming bans are in effect at the Shore as Erin approaches

In a late-August week when hundreds of thousands have gathered at the Jersey Shore hoping to mine what is left of summer, some barrier island towns are all but closing their No. 1 attraction — the Atlantic Ocean.

With the approach of Hurricane Erin expected to act like a performance-enhancing substance on already-agitated waters, Atlantic City, Margate, Ocean City, and Wildwood are among the beach towns that have banned swimming until further notice.

The National Weather Service has posted coastal flood warnings for the Jersey Shore and Delaware beaches, in effect from 5 p.m. Wednesday until 2 a.m. Saturday, with the potential for “major” flooding in isolated areas.

Tropical-storm force winds, gusting to 45 mph, are expected in the beach towns, said Bob Larsen, senior meteorologist with AccuWeather Inc.

At 11 a.m., the National Hurricane Center reported that Erin had regained strength and its top winds had reached 110 mph, just shy of Category 3 major status.

It was predicting that the strongest winds at the Jersey Shore would arrive around 8 a.m. Thursday.

However, the most-significant flood impacts are likely with high tides Thursday evening, the weather service says.

However the most-significant flood impacts are likely with high tides Thursday evening, the weather service says. The impending new moon which occurs Saturday, is likely to give an extra kick to tides, said Larsen.

The back bays are apt to slosh over as onshore winds continue to push up the water and inhibit drainage as they stir up the ocean surf dangerously with rip currents. Near-shore wave heights could reach as high as 12 feet, the weather service says.

They might even reach 15 feet, said Ed Schneider, head of the beach patrol in Wildwood, where some lifeguards are on duty — to keep people out of the water.

He said even the surfers may not want any parts of the Atlantic this week, adding that the steady onshore winds would make the ocean seem “like a washing machine.”

In imploring residents and visitors not to challenge the ocean, New Jersey Gov. Phil Murphy went so far as to invoke Jaws, the Peter Benchley novel and blockbuster 1970s movie.

“I think going in the ocean for the next number of days is something you gotta avoid,” he said, referring to two recent drowning tragedies in Seaside Heights and Belmar.

“We’ve already had a very tough riptide summer, particularly over the last several weeks,” he said. “The ocean is quite angry.”

The rip currents and nuisance flooding so far this week have been driven primarily by steady onshore winds, generated by weather systems well north of Erin, which still was hundreds of miles south of Cape May late Wednesday morning.

Rain at the Shore Wednesday and on the mainland — where localized downpours are possible later in the day, the weather service says — actually are related to the anti-Erin, the front that is going to force it out to sea.

But as Erin picks up speed and moves north and agitates the ocean like a giant plunger, “We’re going to see bigger and bigger waves,” said Kimberly McKenna, interim director of the Stockton University Coast Resources Center.

While the center of Hurricane Erin in all likelihood won’t get any closer than 350 miles to Cape May as it arcs offshore, that won’t spare some fragile barrier island beaches from getting an unwanted makeover.

The waves could erase significant sands in “hot spot erosion areas,” especially near inlets, she said. Waves, more than winds, remove sand from beaches and carry it offshore.

The worst of the erosion is likely to occur Thursday, she added, and among the more vulnerable beaches would be those of Ocean City, Strathmere, Avalon, and North Wildwood.

“Ongoing beach erosion” in North Wildwood already has resulted in closing off beach access from Second to Sixth Avenues. The town also announced it had moved the 50th Around the Island Row from Tuesday to Saturday.

North Wildwood said it was preparing for “higher levels of flooding” for Thursday high tide around 8 p.m.

The weather service said the duration of the flooding threat remained unclear, but it would continue at least through Thursday.

Along with Erin’s influence, the tides could get a further kick from the approaching new moon: When the moon is full or not visible, it is aligned directly with the sun and earth, increasing the tidal pull.

The potential for “moderate” flooding with the Thursday high tide has increased, the weather service said in its discussion late Tuesday afternoon.

Conditions at the Shore will likely deteriorate Wednesday night into Thursday, with thunderstorms possible.

Erin will be a nonevent on the mainland. Showers are possible Wednesday, but that would be related to that other system.

Friday and Saturday should be fabulous in the Philly region, and at the Shore, with sun and highs around 80 degrees, the weather service says.

Whether the ocean will be on its best behavior is another matter.