Bertha strengthened from tropical-storm levels during the night, with maximum sustained winds of almost 90 mph (120 kph) as of this morning at 11 a.m. EST, the U.S. National Hurricane Center said in the latest advisory on its Web site. Hurricanes have maximum sustained winds of at least 74 mph.
The storm was likely to reach Category 2, with winds of over 96 mph, today or tonight, the agency said. If the storm moves as predicted, it could threaten Bermuda, about 670 miles (1,078 kilometers) east of the North Carolina coast, by July 12.
The eye of the hurricane was about 775 miles east of the northern Leeward Islands, which include Antigua and St. Kitts. The storm was moving west-northwest at 15 mph, the center said.
"It is still too early to determine if Bertha will eventually affect any land areas,'' according to the advisory. "Some additional strengthening is forecast during the next couple of days.''