Omar a hurricane once again in Atlantic

MIAMI (Reuters) - Omar regained hurricane strength in the Atlantic Ocean on Friday but did not pose an immediate threat to land after causing little damage this week as it blasted through the northern Caribbean.

The 15th storm of a busy Atlantic hurricane season, Omar had weakened to a tropical storm after a close encounter with the U.S. and British Virgin Islands, the Dutch/French island of St. Martin and other small Caribbean nations and territories.

But the U.S. National Hurricane Center said its sustained winds had strengthened again to 75 miles per hour (120 km per hour), making it a minimal Category 1 storm on the five-step hurricane intensity scale.

Omar was about 660 miles east of Bermuda and its forecast track had it heading in the general direction of Portugal's Azores Islands. Forecasters say long-range predictions have large margins of error.

The storm was expected to weaken again, becoming a tropical storm with winds below 74 mph, within a day.

Omar roared through the northern Caribbean as a powerful Category 3 hurricane with winds of 125 mph late Wednesday and early Thursday but made a direct hit only on a tiny, uninhabited island in the middle of the Anegada Passage.

It sank boats in harbors and knocked down trees and utility poles on a number of islands, but caused little serious damage, according to officials in the region.

Omar briefly disrupted oil operations in Venezuela after forming on Tuesday north of the Dutch island of Curacao, and forced the shutdown of processing units at the Hovensa refinery in St. Croix in the U.S. Virgin Islands.

Officials at the 500,000-barrel-per-day refinery, which is jointly owned by Hess and state-owned Petroleos de Venezuela, restarted the facility after finding no significant damage.

(Reporting by Jim Loney)