7.10.2008 8:49 AM

Chance of Hurricane Bertha Affecting Bermuda: 40%

On the Seventh Day, Hurricane Bertha Regains Strength

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After having lost major hurricane status the day before, a resurgent Hurricane Bertha grew back into a Category 2 storm July 10, 2008. There was a better than 40% chance that tropical storm-force winds from Bertha would affect Bermuda.

Photo: NOAA

By Dan Shapley

Hurricane Bertha has regained Category 2 hurricane strength, with maximum sustained winds of 105 mph, and could strengthen further, according to the latest forecast from the National Hurricane Center.

The first hurricane of the 2008 Atlantic storm season when it formed July 3, and the first major hurricane, Bertha was reduced to a Category 1 storm Wednesday.

Hurricane Bertha is not expected to make landfall, as it skirts to the east of Bermuda. But there's a better than 40% chance that tropical storm-force winds will whip the island. There is, at this point, no chance seen that tropical storm-force winds will affect the United States.

National Hurricane Center
This chart shows the probability that tropical storm-force winds from Hurricane Bertha will affect different areas, with green representing a 5% chance and purple a 100% chance.

The first tropical storm of the Atlantic season, Arthur, brought punishing rains to parts of Central America June 1, right in time for the official start of the hurricane season. The peak of activity most years occurs in late summer.

Hurricane Bertha's formation followed an active period in the eastern Pacific Ocean, where three tropical storms and the first hurricane of the eastern Pacific season, Hurricane Boris, formed within days of each other last week.

The forecast from the government's Climate Prediction Center says it's likely that 2008 will be an active year for hurricanes in the Atlantic basin, which includes the Caribbean. There's a good chance we'll see 12 to 16 named storms, including six to nine hurricanes and two to five major hurricanes (Category 3, 4 or 5 on the Saffir-Simpson Scale). Average is 11 named storms including six hurricanes, two of them major storms.

Last season did not produce the predicted number of storms. There were more named storms but fewer hurricanes than predicted. Those hurricanes that did form intensified rapidly before landfall, and the first-ever record of back-to-back Category 5 landfalls came when Hurricanes Dean and Felix hit Central America. (The names Dean and Felix, along with Noel, a weaker but deadly 2007 Caribbean storm, have been retired.)

The last several months have seen a flurry of science related to global warming and hurricanes. A longtime proponent of the idea that warmer ocean temperatures will produce stronger storms, Kerry Emanuel, has called that hypothesis into doubt. But the government has said that warmer oceans will produce fewer, but stronger storms in the coming decades. The jury, it seems, is still out, as scientists study the complex forces that influence hurricane behavior.

This year, a lingering La Niña (cool pattern) in the Southern Pacific, warmth in the tropical Atlantic, and the strong-phase of a multidecadal storm activity cycle are expected to be driving forces behind an active storm year.

2008 Tropical Storms and Hurricanes - Atlantic

Tropical Storm Arthur formed quickly on May 31 off Belize and lost tropical storm strength in fewer than 24 hours, amd brought punishing rains of 10-15 inches to parts of the Yucatán Peninsula, including Mexico and Guatemala.

tropical storm arthur
NOAA

Hurricane Bertha after forming as a tropical storm July 3 in the far eastern Atlantic, Hurricane Bertha debuted as the Atlantic's first hurricane July 7 and quickly grew to major hurricane status even as it appeared less likely the storm would make landfall.

hurricane bertha
NASA