Danielle Becomes Category 4 Hurricane, 2010 Season's Strongest

Hurricane Danielle, the strongest Atlantic storm this season, is heading toward Bermuda with waves high enough to dwarf a three-story building and winds capable of knocking down trees, the National Hurricane Center said.

The Category 4-level storm, packing winds of 135 miles (215 kilometers) an hour, is expected to pass east of the wealthy British territory tomorrow as a “major” hurricane before weakening, the U.S. center said.

“Large and dangerous surf conditions are expected in Bermuda during the next few days,” according to a center advisory. Storm swells will reach the U.S. East Coast today, and “large surf and dangerous rip currents are expected throughout the weekend,” it said. Bermuda issued a small-craft advisory.

Bermuda has the world’s third-largest per capita income because of its international business services and its luxury resorts, according to the CIA World Factbook.

The system was about 480 miles southeast of Bermuda and moving northwest at 12 mph, the center said in an online advisory at 11 a.m. Miami time. The threshold for a major hurricane is 111 mph.

Winds of at least 74 mph, hurricane strength, extend 60 miles from the center of the storm, and waves were as high as 42 feet in its center, the agency reported.

Danielle’s Threat

The Bermuda Weather Service warned of 46-mph winds tomorrow and swells outside its reefs as high as 18 feet (5.5 meters). The service forecasts Danielle will pass within about 270 miles of Bermuda at its closest. The hurricane center said Danielle’s hurricane-force winds stretch up to 60 miles from its eye while tropical storm-force winds of at least 39 mph extend out as much as 205 miles.

An Air Force Reserve reconnaissance flight will investigate Danielle this afternoon.

Danielle has surpassed Hurricane Alex as the season’s most intense storm. Alex had 105-mph winds when it hit northeastern Mexico on June 30 and dissipated over land.

Danielle will transform into an extra-tropical storm by the middle of next week, and while it won’t have the structure or the power of a hurricane, its remnants will still be powerful, with winds about 69 mph, said Dennis Feltgen, a spokesman for the hurricane center.

Windy Azores

Those remnants are expected to be absorbed by a low- pressure system near Greenland, said Jeff Masters, co-founder of Weather Underground Inc. in Ann Arbor, Michigan. Masters said the Azores may be brushed by high winds next week.

Behind Danielle, Tropical Storm Earl is packing 45 mph winds and is forecast to intensify over the Atlantic. The system is about 1,300 miles east of the northern Leeward Islands, the hurricane center said on its website.

Earl is heading west at 17 mph, expected to become a hurricane by Aug. 29 and a major hurricane on Sept. 1 as it begins to curve north toward Bermuda. The British Virgin Islands, St. Kitts and Barbuda could be hit, according to a map of potential storm tracks on the Hurricane Center website.

“The ocean and the atmosphere appear to be favorable for intensification,” according to the hurricane center. “Accordingly, the official forecast shows Earl becoming a major hurricane.”

Low-Pressure Barrier

Both Earl and Danielle are being deflected away from the U.S. by a low-pressure trough along the East Coast, said Jim Rouiller, senior energy meteorologist at the commercial forecaster Planalytics Inc. That barrier may break down soon and open the way for storms, he said yesterday.

“I’m beginning to feel more and more confident that the Gulf and Florida will become targets for hurricane strikes as we approach and move through the Labor Day weekend,” Rouiller said. “Once this trough is removed, the U.S. seaboard along with the Gulf will be under the gun.”

Florida is the second-largest orange producer after Brazil. The Gulf of Mexico is home to about 31 percent of U.S. oil output and 10 percent of natural gas production. Labor Day in the U.S. is on Sept. 6 this year.

The hurricane center said it’s also tracking a tropical wave about 200 miles south-southeast of the Cape Verde islands with a 70 percent chance of becoming a tropical cyclone in the next two. Tropical cyclones are rotating systems that range from depressions to hurricanes.

Hurricane Frank

In the Pacific, Hurricane Frank weakened slightly and was packing 75 mph winds, the Miami-based center said. The Category 1 storm on the five-step Saffir-Simpson scale was about 315 miles south-southeast of Baja California and moving west- northwest at 6 mph. Frank is forecast to weaken further today and tomorrow.

Six storms have formed in the eastern Pacific this year, behind the pace of 2009 and 2008, when 11 named storms had developed. The eastern Pacific hurricane season runs from May 15 through Nov. 30.

In the western Pacific, six tropical storms or typhoons have formed this year, where 10 had been tracked by this time last year.

While the Atlantic is ahead of its statistical average for storm production, activity in all the oceanic basins in the Northern Hemisphere where tropical cyclones form is the lowest since 1948, when reliable records were first kept, said Masters.

Quieter Pacific

The eastern Pacific is quieter because a La Nina, or a below-normal cooling of sea-surface temperature, has formed in the central Pacific. That keeps storm production down off the coast of Mexico, Masters said.

One theory for why the numbers of storms is low globally is that record-setting heat waves in Moscow, New York and elsewhere may have caused an active monsoon season over Asia, which means rising air in the atmosphere, Masters said.

“If you have all that rising air over Asia, you have to have sinking air somewhere else, and that sinking air was both over the western Pacific, where they have had an unusually quiet typhoon season, and then over the Atlantic as well,” Masters said.

Sinking air damps storm formation, and caused a few weeks of quiet in the Atlantic from July through early August, he said. That has changed in the Atlantic. In the western Pacific, the Japanese Meteorological Agency is tracking a tropical depression in the East China Sea near the Ryukyu islands of Japan.

To contact the reporters on this story: Brian K. Sullivan in Boston at bsullivan10@bloomberg.net; Alex Morales in London at amorales2@bloomberg.net

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