How bad will Hurricane Irene be for LI?

Whether Irene strikes Long Island directly, is a near miss or weakens significantly, we still could be in for strong winds, high seas, shoreline flooding and heavy rain, experts say.

How bad will it be?

That depends on variables.

First, the intensity of the storm. The National Weather Service predicts Irene could come calling as anything from a tropical storm with sustained winds under 74 mph to a weak Category 2 hurricane with winds of more than 100 mph.

Ross Dickman, meteorologist in charge of the Upton office, said the other major issue is the storm track. Its shift west Thursday indicates the storm may pass directly over New Jersey, which could weaken it, and reach the Island Sunday evening.

Other issues are the storm path's angle to the coastline and whether it runs into land on its way north. If the storm hits the coast to the south, it will dissipate much of its force but we'll still get high winds and rain.

Will tides affect us?

"There is a new moon on Sunday and high astronomical tides, so if it comes in at high tide it's going to have a huge impact compared to if it's a low tide," Dickman said.

Stony Brook University oceanographer Malcolm Bowman points out that Hurricane Gloria in 1985 came with a 6-foot storm surge. "But it hit at low tide so there wasn't a huge amount of flooding on Long Island. The biggest flooding incident in recent memory was the nor'easter in December of 1992 that had a surge of close to 6 feet" that arrived at high tide.

Don Caetano of the Federal Emergency Management Agency said, "If you live south of Sunrise Highway, you need to be prepared to deal with storm surge."

What will winds do?

As the storm approaches and comes through the region, the winds will be out of the northeast and mimicking "a very powerful nor'easter," Dickman said. That could mean trouble for low-lying areas along the North Shore, such as Asharoken and Bayville, because they have beaches vulnerable to winds from the northeast, and those winds bottle up water in the Long Island Sound by blocking usual outlets for tides to drain.

"The size of the storm [hurricane] is quite a bit larger than average," Bowman said. "That means we're going to have stronger winds at a greater radius from the center." Because of this larger size, the storm will take a while to pass over the region. "We could have very strong winds for 12 hours."

How about rain?

Based on what has fallen in the Caribbean, Dickman said, Irene could dump more than 6 inches of rain on the area, which could pose some travel problems. Caetano added, "There will be flooding because of the rainfall, and there will be downed trees because of the saturated ground [from recent heavy rains] and the additional rain."

Dickman said the trees then could take down power lines.