Gustav, and more

top story

Growing storm menaces U.S.

others form over Atlantic

August 30, 2008|By Frank D. Roylance | Frank D. Roylance,frank.roylance@baltsun.com

All eyes are on Hurricane Gustav today as the Caribbean storm threatens to become a dangerous Category 3 and a serious threat to Louisiana and the northern Gulf Coast. But Gustav is not all that hurricane forecasters have to contend with this weekend.

Out in the Atlantic Ocean southeast of Miami, a storm named Hanna also was expected to reach hurricane strength this weekend and threaten the Bahamas by midweek.

And a tropical wave was strengthening off the coast of Africa - the breeding ground for the powerful Cape Verdean hurricanes that sometimes cross the ocean to batter the U.S. East Coast. If it is next to reach tropical storm strength, it will be named Ike.

"It's important that people understand we're in the peak of an active hurricane season. That means an increased threat to the U.S., as we're seeing with Gustav and the H storm," said Gerry Bell, the lead seasonal hurricane forecaster at the national Climate Prediction Center in Camp Springs.

"People need to have safety plans in place."

A team of emergency responders was scheduled to leave Maryland for Louisiana at 4 a.m. today, answering a call for assistance from state officials there, according Baltimore police spokesman Sterling Clifford.

After two relatively quiet years, the 2008 Atlantic hurricane season is even busier than forecasters had originally predicted. Climatologists say it's the resumption of a decades-long cycle of heightened Atlantic hurricane activity that began in 1995.

Gustav became a minimal hurricane yesterday afternoon, and it could reach Category 3 strength - with top sustained winds of 111 mph or more - by the time it crosses western Cuba today and enters the Gulf of Mexico.

At 11 p.m. yesterday, Gustav was just southwest of the Cayman Islands and strengthening as it moved northwest at about 11 mph, with top sustained winds of nearly 80 mph, the National Hurricane Center said.

On its current track, the storm would pass over western Cuba today and enter the southern Gulf of Mexico tonight or tomorrow, the center said.

The storm left 71 dead in Hispaniola and Jamaica this week. Forecasters warned of storm surge flooding of 8 to 13 feet in Cuba, and 6 to 12 inches of rain. Some places could receive 25 inches.

In the United States, residents of the northern Gulf Coast were preparing their escape plans, fearful that Gustav would demolish all they had done to recover from the catastrophic storm season of 2005.

This year's storm activity began early, in late May, when Tropical Storm Arthur formed and drenched the Yucatan Peninsula.

Last month proved to be the third-most-active July since 1886 - after 2005 and 1916. Bertha was born on July 3. It became a Category 3 hurricane far out in the Atlantic and was the longest-lived July storm on record - 17 days. Tropical Storm Cristobal crept past the North Carolina coast in midmonth. Dolly made landfall in Texas on July 23 as a Category 2 hurricane, followed on Aug. 5 by Tropical Storm Edouard.

Tropical Storm Fay meandered back and forth across Florida last week, inundating many communities with more than 20 inches of rain. It was Fay's remnants that brought yesterday's rain to Maryland.

With so much activity early in the season, government prognosticators now expect a total of 14 to 18 named storms. (The average is 11.) Eight have already formed. Seven to 10 storms are forecast to become hurricanes. Three already have.

The stage for busy storm seasons was set in 1995, scientists say, when atmospheric and water temperatures in the Atlantic shifted into a pattern conducive to storm formation that typically lasts 10 to 40 years.

"It's a whole set of conditions," Bell said. One is low wind shear, meaning that wind speed and direction don't change much as warm air rises inside a hurricane, allowing the storm to grow stronger. High shear aloft will cut off storm formation.

Another factor fueling the active season is warmer-than-normal ocean temperatures. High sea-surface temperature - typically above 80 degrees - is the fuel that powers hurricanes.

A similar hurricane-friendly setup prevailed in the Atlantic from 1930 to 1970, and those decades saw a series of powerful storms make landfall in the U.S.

After that, the Atlantic calmed and remained relatively quiet, on average, until 1995. Devastating storms can still boil up during "quiet years," however. An example was Andrew, which flattened parts of South Florida in 1992.

There have been several punishing seasons in recent years. In 2004, four hurricanes made landfall in Florida in just six weeks. They killed 152 people, demolished 27,000 homes and caused $45 billion in property damage.

Before the 2005 season ended, forecasters had run through 27 storm names, a record. The most infamous storms - Katrina and Rita - devastated New Orleans and the Texas, Louisiana, Mississippi and Alabama coasts. Storm deaths in 2005 totaled 2,280.

Then we caught a break. Only 10 tropical storms formed in 2006, and only five reached hurricane strength. The comparative lull, Bell said, was related to increased wind shear in the Atlantic basin.

Last year was busier; there were 15 named storms, more than the average of 11. But they had little impact on the mainland U.S.

The key to this year's resurgent activity, Bell said, may be the lingering, long-range effects of last year's La Nina event - which has suppressed convection and thunderstorm activity in central Pacific and wind shear in the Atlantic.

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