By Michael Christie
MIAMI (Reuters) - Strengthening far more swiftly andvigorously than predicted, Hurricane Bertha became a "major"hurricane in the open Atlantic on Monday, with sustained windsof at least 115 miles per hour (185 kph), U.S. forecasterssaid.
The second named storm of the 2008 Atlantic hurricaneseason was heading west-northwest in the direction of Bermudawhen it became a Category 3 storm on the five-stepSaffir-Simpson scale of hurricane intensity, the NationalHurricane Centre said.
"A gradual turn toward the northwest with a decrease inforward speed is expected over the next couple of days," theMiami-based centre said.
That could take Bertha near Bermuda, a wealthy mid-AtlanticBritish colony that is viewed as one of the more storm-proofislands in the region, with tough building codes and astorm-conscious population.
The National Hurricane Centre said it did not expect Berthato get much stronger due to unfavourable atmospheric conditionsin its path. But the storm has already delivered surprises andforecasting long-range hurricane intensities and tracks is anuncertain science.
At 10 p.m. British time, the storm's centre was locatedaround 1,150 miles (1,855 km) southeast of Bermuda and it wasmoving at around 12 mph (19 kph) to the west-northwest.
Energy markets have paid close attention Atlantic stormssince the devastating 2004 and 2005 hurricane seasons, duringwhich a number of powerful hurricanes ripped through the Gulfof Mexico, toppling oil rigs and severing pipelines.
None of the computer models used to predict storm tracksindicated Bertha would steer south into the Caribbean or towardthe Gulf.
Hurricane forecasters have predicted this six-month season,which began on June 1, will be average or above average. Anaverage season has 10 tropical storms, of which six reachhurricane strength with winds of at least 74 mph (119 kph).
The record 2005 season, which included Katrina whichswamped New Orleans and killed 1,500 people on the U.S. GulfCoast, saw 28 storms.
Bertha formed last Thursday near the Cape Verde islands offAfrica. It is unusual for storms to form so far east so earlyin the season. When it does happen, it is frequently aharbinger of heightened storm activity.
More information about the hurricane is available at theNational Hurricane Centre's Web site(http://www.nhc.noaa.gov/#BERTHA).
(Editing by Alan Elsner and Jane Sutton)
