The 2007 Atlantic hurricane season will be more active than normal with 13 to 17 tropical storms, and as many as ten of them could become hurricanes, the U.S. government's top climate agency predicted.
Of the seven to 10 hurricanes forecast, three to five will be major ones of Category 3 or higher with winds over 110 mph, the National Oceanic and Atmospheric Administration said in its annual forecast.
An average Atlantic hurricane season brings 11 tropical storms, of which six reach hurricane wind speed of 74 mph, including two major hurricanes, NOAA said. The hurricane season, which officially starts on June 1, typically peaks between Aug. 1 and late October.
"We are right now in ... a period of more active hurricane seasons," said NOAA Administrator Conrad Lautenbacher. "It just takes one hurricane to make it a bad year for everyone here," he said.
Earlier forecasts for the season also have predicted the return of an active pattern this year, after last season when no major hurricanes hit the United States. Forecasters had expected an active 2006 season, but only 10 storms formed.
In the devastating 2005 Atlantic hurricane season a record four major hurricanes hit the United States, including Katrina, which devastated New Orleans, killed 1,300 people and caused $80 billion in damage. The 2005 season generated 28 tropical storms, of which 15 became hurricanes.
La Nina Threat
Weather forecaster AccuWeather.com has predicted 13 or 14 tropical storms or hurricanes would form in the Atlantic this year and six or seven could hit the United States, with the Gulf Coast and Gulf of Mexico oil installations at high risk.
The Colorado State University team under forecast pioneer William Gray predicted 17 storms, of which nine would become hurricanes, and London-based Tropical Storm Risk predicted 16.7 storms and 9.2 hurricanes.
Gerry Bell, a top NOAA forecaster, said while it was not possible to predict how many hurricanes might make landfall in the United States this year, similar seasons have seen between two and four storms hit the U.S. Atlantic and Gulf coasts.
But he said La Nina conditions could develop in the eastern Pacific in the next one to three months, adding to the likelihood of above-average hurricane activity.
La Nina, which means "little girl" in Spanish, is an abnormal cooling of ocean surface temperatures in the equatorial Pacific. El Nino, or "little boy," has the opposite effect.
"If La Nina develops, storm activity will likely be in the upper end of the predicted range, or perhaps even higher depending on how strong La Nina becomes," said Bell.
NOAA will update its hurricane outlook in early August.