A weaker Irene expected at high tide

A direct hit on Long Island by Hurricane Irene on Sunday morning would bring good news and bad news.

The good news is that it's unlikely to be more than a weak Category 1 hurricane, the National Weather Service in Upton says, compared with 1985's Category 2 Gloria, the last hurricane to hit here.

The bad news is that Gloria crossed the Island at low tide while the center of Irene is likely to hit either the South Shore coast or the North Shore at or close to high tide, depending on when it arrives.

Ross Dickman, the Weather Service meteorologist in charge in Upton, said the forecast calls for a "low-end Category 1" storm with wind speeds of 75 to 90 mph, with higher gusts.

The big question is when the storm's center -- with the most severe weather -- comes ashore. Dickman said Friday to expect that from 8 a.m. to noon Sunday.

If it's on the early part of that spectrum, it will hit the South Shore beaches at or near high tide, making the accompanying storm surge that much more destructive. If the center passes over closer to noon, it will more closely coincide with high tides on the North Shore, such as in Bayville, where high tide is about 11 a.m.

To the east of the storm track line, winds will be from the east or east-southeast as the storm approaches and then shift northeast and then northwest after the center crosses the Island, Stark said. West of the track, winds will be more northeast to north as the storm approaches and then shift to northwest or west as the center passes. These directions have implications for boats and beaches. Beaches in places like Bayville, Asharoken, Orient Point and the north side of Montauk are vulnerable to high winds from the northeast.

"It's a new moon so we're having tides that are a little bit higher than normal," said Jay Tanski, a coastal researcher with the New York State Sea Grant Extension Program. So "the timing is going to be very, very important."

Tanski said Irene so far is following a track similar to Gloria's. "Gloria came through an hour after low tide," he said, so even with a record storm surge of about 7 feet in southwestern Nassau, it caused limited coastal flooding.

With Irene, he said, "it could get very bad" east of the storm track on the South Shore or on the North Shore west of the track depending on the tide.

"This storm is a little bit slower-moving than Gloria was," he said. "Gloria came through at about 20 miles an hour so it was in and out. This storm is also bigger than Gloria was. So it's going to be a bigger, slower moving storm" which means there will be more time for larger waves to form, and those waves will pound the shoreline longer. That will exacerbate the storm surge problem and cause erosion.

Tanski warned people not to be complacent just because they came through Hurricane Gloria unscathed. He expects coastal flooding in this storm to be worse because even though the wind speeds will be lower, that will be more than offset by the higher tides and larger storm surge. With Irene, he said, “it could get very bad.”
Nonetheless, on the South Shore, he said, models show ocean swells as high as 28 feet. "That can pile up water on the shoreline," Tanski said.