Flood warnings are posted for the entire Jersey Shore as Erin makes its closest approach

Hurricane Erin’s drive-by impacts are forecast to generate multiple rounds of flooding in New Jersey beach towns from Sandy Hook to Cape May Point, and tropical storm warnings were in effect for the nearshore waters.

Even though rains may be negligible, the National Weather Service hoisted coastal flood warnings in effect until 2 a.m. Saturday, with the potential for localized “major” flooding Thursday evening.

At the very least, the agency says, expect flooding on roads, some of which may become impassable, and potential structural damage to buildings, particularly in the back-bay areas of the barrier islands.

Minor flooding is expected to persist at high tides early Friday and Saturday, the weather service says.

Winds were gusting to near 30 mph Thursday morning at the Shore and could get up to 45 mph, forecasters said, water was the bigger concern.

Shore officials implored the natives and frequenters to educate new visitors to the hazards of Shore flooding, which got off to a pre-Erin head start this week as a result of steady onshore winds.

» READ MORE: Flood warnings? Beach restrictions? Shore visitors are making the most of their Erin-spoiled week.

“Many of the people in town may not be familiar with flooding events,” said Jay Gillian, mayor of Ocean City, where nuisance back-bay flooding is common.

The back-bay areas likely will get the worst of it, said Bob Larsen, senior meteorologist with AccuWeather Inc. Those winds are causing water pileups in bays and inhibiting drainage.

And Erin-stirred storm waves, up to 12 feet near the shore, along with the impending new moon, are going to exacerbate conditions.

The worst of the flooding is due around 8 p.m. Thursday, the weather service says, which would be several hours after Erin is supposed to make its closest approach to the Shore.

At midmorning Erin’s center was estimated to be around 400 miles southeast of Cape May, and beginning to take a turn toward the northeast. At last report, top winds were 105 mph, the hurricane center said, and the hurricane was traveling north-northeast at 17 mph.

Erin is a large storm in areal coverage, and on Wednesday it was showing renewed vigor, Larsen said.

Compared with Tuesday, when it had weakened, Erin had “a much better look to it, a better structure,” he said.

At 5 p.m. Wednesday, it was about 650 miles south of Cape May with peak winds of 110 mph, and was picking up speed, moving north at 14 mph.

It was expected to make a sharp right turn off the coast of the Carolinas and sail northeast over the North Atlantic on Thursday.

In the Philadelphia region, “no rain will fall from Erin,” Larsen said. Rather, Wednesday’s rains were the result of the anti-Erin, a system that was going to shoo Erin off the coast.

Tidal flooding is possible along the Delaware, but that would be only indirectly related to the hurricane.

Unfortunately for the Shore towns, the stars, or at least the moon, are aligned to raise the water levels.

Although it is out of sight, the new moon, which occurs Saturday, has tugging effects on the tides comparable to those of the full moon. In both cases, the Earth, sun, and moon are all lined up.

The new moon is a factor in the advisories along the Delaware River.

At the Shore, Erin’s plunging action of the ocean is going to cause some beach erosion and further congest the back bays.

Wave heights within about 25 miles of the Shore could reach 12 to 17 feet on Thursday, Larsen said.

With Erin’s outskirts intensifying rip currents, towns all along the Shore continue to restrict swimming, and those bans likely will continue into the weekend.

Ed Schneider, head of the beach patrol in Wildwood, where unusually high tides on the mammoth beach radically shortened the walk from the boardwalk to the water Monday and Tuesday, said he hoped new visitors understood the reasoning for the restrictions.

“We’re very mindful about those people. It might be their first time to Wildwood,” he said. But he added that keeping people out of the water also was about the safety of those who might have to rescue them.

As Erin spins into obscurity, the warnings and advisories will back off, and the atmosphere’s behavior will improve immeasurably Friday.

The lingering flood threats notwithstanding, Friday, Saturday, and Sunday are expected to be fabulous days throughout the region with sunshine prevailing and highs in the 80s, with just an outside chance of showers on Sunday.

As for when it will be safe to go back into the water: Stay tuned.