Hurricane Earl path stretches from North Carolina to Boston Harbor

Hurricane Earl, some 300 miles south of North Carolina's Cape Hatteras, has now prompted tropical-storm or hurricane warnings from the Tar Heel State's coast to the Massachusetts-New Hampshire border.

Coastal New England from Westport, Mass., to Hull, a town at the end of a peninsula forming part of Boston Harbor, is the latest swath of coastline to come under a hurricane warning.

From the North Carolina-Virgina border up to Westport, the entire coastline is under a tropical storm warning. The Delmarva Peninsula is under a hurricane watch as well.

"We've talked about people needing to be prepared and getting their plans ready. We're past that," says Craig Fugate, director of the Federal Emergency Management Agency (FEMA). "This is a day of action." People need "to be ready to heed any additional evacuation orders as this storm continues to track to the north," he says.

The storm continues to pack maximum sustained winds of 140 miles per hour and is working its way toward the coast at about 18 m.p.h.

Track forecasts for hurricane Earl have been holding up pretty well, according to Bill Read, director of the National Hurricane Center in Miami.

"The storm is "pretty much right down the track we we've been anticipating now for two days," he says.

But the storm's track isn't the only factor feeding concerns about the storm's effect on the Eastern seaboard. Hurricane Earl's winds extend far beyond its tight central eye. Earl is a broad storm, with tropical-storm-force winds extending some 200 to 230 miles from the center. Hurricane-force winds extend for about 90 miles from the eye.

And Earl could get larger. The storm appears set to undergo a process called eyewall replacement -– common to major tropical cyclone, notes Dr. Read.

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