More to come in busy Atlantic hurricane season

The 10 tropical storms and hurricanes that ripped through the Atlantic and Caribbean during this busy hurricane season savaged Haiti, Cuba and the U.S. Gulf coast, and conditions are now ripe for more.

Residents of the Atlantic-Caribbean danger zone should not let down their guard, despite a brief lull in the action following Tropical Storm Josephine's demise two weeks ago and Hurricane Ike's strike on the Texas coast, experts said.

"Conditions are still favorable for hurricanes. People really need to stay on their toes," said Gerry Bell, the lead hurricane season forecaster for the U.S. National Oceanic and Atmospheric Administration.

Forecasters had predicted the season, which runs through November 30, could produce up to 18 cyclones, and the warm sea temperatures, low wind shear and other factors that contribute to the formation of hurricanes are still in place.

Water in the Caribbean and Atlantic is warmer than usual by 0.9 to 2.7 degrees Fahrenheit (0.5 to 1.5 degrees Celsius), Bell said. Hurricanes feed on warm sea water.

Patches of cooler water, drawn from the depths by the passage of powerful hurricanes like Ike and Gustav, have appeared around Cuba and in the Gulf of Mexico, but they are not likely to have a big impact on future storms.

Wind shear, which is the difference in wind speeds at different levels of the atmosphere and which can disrupt nascent hurricanes, is relatively low.

El Nino, the eastern Pacific warm water phenomenon that can dampen Atlantic storm formation, has not developed. Neutral El Nino conditions are expected for the rest of the season, experts said.

"Through October 15th I would not let my guard down on the (U.S.) eastern seaboard at all," AccuWeather forecaster Joe Bastardi said, predicting another three to five storms.

"Between the 25th (of September) and 15th of October the Caribbean will light up, but first, something may form off the Carolinas," he said.

TOUGH YEAR

Six consecutive Atlantic tropical storms and hurricanes hit the United States from late July to mid-September, causing billions of dollars in damage. Four in a row swamped Haiti, killing hundreds of people.

Gustav and Ike crushed Cuba before heading off to the U.S. Gulf Coast, where they rampaged through oil and gas fields.

At this point, just after the statistical peak of the six-month season, there is no comparison to 2005, the all-time record-breaker with 28 storms, when forecasters ran out of storm names and had to resort to the Greek alphabet. That year spawned Hurricane Katrina, which devastated New Orleans.

On September 18 of 2005, Rita formed. It was the 17th storm of the season and eventually became a 180 mph (290 kph) monster, one of the strongest hurricanes in history.

But not even in 2005 did six storms in a row hit the United States.

In fact, the U.S. National Hurricane Center says that so far it has not found another year since records began in 1851 in which the United States was hit by six tropical cyclones in a row, but it was still digging through databases.

The tendency to target U.S. shores is partly due to the atmospheric conditions that steer hurricanes. In some years, many of the storms that charge across the ocean eventually curve harmlessly northward without reaching the United States.

"We've had an extensive area of high pressure in the middle and upper atmosphere that has helped to steer the hurricanes west at lower latitudes," Bell said. "They have not recurved into the Atlantic."