The storm already is large for a hurricane, with hurricane-force winds extending some 50 miles from the center and tropical-storm-force winds reaching out as far as 205 miles from the core.
"It's a large storm to begin with," says Bill Read, director of the National Oceanic and Atmospheric Administration's National Hurricane Center in Miami. "As these storms move northward into the mid-latitudes, they grow as a matter of natural course. So we're going to have a very large tropical cyclone move up the eastern seaboard over the next five to seven days."
A land-falling Irene would mark the first direct hit from a hurricane since 2008. That year, Ike struck the Texas coast at Galveston Island as a Category 2 storm and drove deep into the continent as a tropical-storm-force storm. Ike caused an estimated $29.5 billion in property damage, second only to hurricane Katrina's $108 billion in damage.
Emergency managers in North Carolina told the Associated Press that they have been taking stock of generators, fork lifts, and other supplies in anticipation of Irene's arrival. In addition, FEMA teams in the state are stepping up their contacts with North Carolina emergency managers to help with evacuation plans and other preparedness measures.
Irene's projected track up the Southeast coast has slowly migrated east over the past two days, taking the storm farther away from Florida than previous forecasts had indicated.