Hurricane Bill, the first of the 2009 Atlantic season, grew quickly into a major Category 3 storm and could strengthen as it curves north, likely missing the eastern US as it passes Bermuda.

With top winds near 125 mph (205 kph), Bill "has undergone a period of rapid intensification" and "is expected to remain a large and powerful hurricane for several days," said the US National Hurricane Center, which sent a plane to probe the swirling cloud mass on Tuesday.

Bill posed no threat to oil installations in the Gulf of Mexico. Authorities in Bermuda, a British territory and reinsurance capital, warned residents to be prepared.

Hurricanes of Category 3 or higher on the five-step Saffir-Simpson intensity scale are considered "major" and are the most destructive type.

There was a 62 percent chance Bill could become a Category 4 hurricane in the next 12 hours, falling in probability afterward, the Miami-based hurricane center said at 10:37 p.m. EDT (0237 GMT on Wednesday).

There was a 10 percent chance of Bill hitting top-strength Category 5 in the next 36 hours, it said.

As of 10 p.m. EST (0400 GMT), Bill was about 555 miles (895 km) east of the Leeward Islands and moving west-northwest at 15 mph (24 kph). A gradual turn to the northwest is expected on Wednesday.

Canada could get weaker Bill

Hurricane expert Jeff Masters, founder of the Weather Underground website, said he expected Bill to move between Bermuda and the US East Coast toward Canada's Maritime Provinces.

"I think the likely main impact (on the US coast) is going to be beach erosion and coastal waves," he said. "Direct impacts are unlikely."

Bill will encounter energy-sapping cool water when it reaches the latitude of North Carolina but could still be a Category 1 hurricane near Nova Scotia and Newfoundland, Masters said.

The National Hurricane Center notes that long-range track forecasts -- from three to five days in advance -- have average errors of several hundred miles.

Meanwhile, energy traders were keeping an eye on the remnants of Tropical Storm Ana, which was producing thunderstorms over Haiti, Cuba and the Bahamas.

The NHC forecast that the storm front had a low chance -- less than 30 percent -- of becoming a tropical cyclone again over the next 48 hours.

One forecaster, AccuWeather.com, said it was unlikely but possible the system could regenerate over the eastern Gulf later in the week. Some forecasters noted Ana already had regenerated once.

Energy markets watch storms in the Gulf of Mexico closely because the region produces a quarter of US oil and 15 percent of its natural gas. – Reuters