Hurricane Erin Strengthens to Category 5

Erin rapidly intensified into a major Category 5 hurricane Saturday morning with maximum sustained winds of 160 mph. After departing the Caribbean, Erin will set its sights on the East Coast of the United States, with the severity of impacts dependent on its track.

Erin is moving over water temperatures that are higher than the historical average not just at the surface but also hundreds of feet deep. These warm waters, combined with very little in the way of dry air and wind shear, have created "near perfect" conditions for rapid intensification, according to AccuWeather Lead Hurricane Expert Alex DaSilva.

How long Erin tracks west before turning to the north will determine how close it comes to the East Coast and Bermuda as well as how widespread the impacts may be next week.

"Erin is forecast to slowly curve to the north as it continues to strengthen over the weekend. At this time, the storm is forecast to remain hundreds of miles off the East Coast," DaSilva said.

A powerful offshore hurricane can produce massive and dangerous waves well away from its center.

"Beaches along the entire East Coast, from Florida to New England and Atlantic Canada, will likely experience rough surf and dangerous rip currents as Erin tracks north and eventually northeast," DaSilva said.

The strength and position of high pressure over the central Atlantic—along with an approaching dip in the jet stream—will be key factors in determining Erin's track next week.

If the high consolidates in size, steering winds from the jet stream would keep Erin well east of the U.S.

A broad area of high pressure to the west could block the steering winds of the jet stream, potentially allowing Erin to drift perilously close to the U.S. East Coast.

At this time, AccuWeather's team of expert meteorologists expects the most likely path of Erin to keep the dangerous eye of the hurricane east of the United States.

However, Erin is forecast to grow in size and strength. Its field of influence may become extensive, with tropical storm conditions possibly extending outward from the center by 100 miles or more.

Protruding coastal areas—such as North Carolina’s Outer Banks, Long Island, New York, and Cape Cod, Massachusetts—face a higher risk of direct and potentially severe tropical storm or hurricane conditions than much of the southern Atlantic, mid-Atlantic and northern New England coasts.

Proximity to the U.S. East Coast will determine the severity of impacts from Florida to Massachusetts and, later, for Atlantic Canada. Even if Erin's center stays east of North Carolina, storm surge of several feet combined with wave action could inundate access roads and force closures. Among the roads that could be inundated or subject to overwash would be portions of NC 12 on the Outer Banks.

Some of the most certain impacts from this hurricane will be dangerous surf, beach erosion, coastal flooding and frequent, strong rip currents along the U.S. East Coast, as well as coastal areas of Bermuda and Atlantic Canada.

“Be vigilant if you’re going to an East Coast beach next week. Be aware of rip current warning signs and only swim in areas with lifeguards on duty,” DaSilva said.

Offshore wave heights may exceed 50 feet at the height of the storm. Waves of this magnitude can be perilous for large freighters and cruise ships and extremely dangerous for small craft.

These massive waves will propagate outward from the center as large swells, reaching coastal areas in the form of powerful breakers. Much of the U.S. East Coast can expect breakers of 5-10 feet in the surf zone. However, in areas of land that extend farther east—such as the Outer Banks, eastern Long Island and Cape Cod—breakers of 10-15 feet are likely.

In Bermuda, waves buffeting the islands may reach 15-25 feet, depending on the proximity of Erin.

As with the U.S. Atlantic coast, conditions in Bermuda will depend heavily on the storm's track and how close it passes.

Wind gusts across the islands are forecast to generally range from 40–60 mph, with an AccuWeather Local StormMax™ of 100 mph expected in the most extreme locations.

A general 2-4 inches is forecast, but lower wind and rain amounts could occur if Erin's track is more than 100 miles to the west.

“People along the East Coast from the Carolinas to New England and Atlantic Canada, as well as Bermuda, should monitor forecast updates closely into next week,” DaSilva said.

In the wake of Erin, two additional tropical waves are expected to move across the Atlantic later in the month, DaSilva noted. "These will be closely monitored as they may follow a similar route to Erin."