The new hurricane warning area now extends from North Carolina's coast, northward to Sandy Hook, N.J., which is just south of New York City. A hurricane warning means hurricane conditions are expected within 36 hours.
A hurricane watch has been issued for areas along the coast north of New Jersey, including Long Island, Martha's Vineyard and Nantucket, Mass.
Meanwhile, Irene's maximum sustained winds have decreased to 110 mph (175 kph). But the National Hurricane Center says some re-strengthening is possible and the storm is expected to be near the threshold between a Category 2 and 3 storm as it reaches North Carolina's coast.