Two More Storms Added to 'Active' 2008 Hurricane Forecast

Tornado Science, Facts and History

An update announced today to the 2008 hurricane forecast calls for two more storms than previously predicted — a total of 17 named storms for the entire season, which officially started June 1 and ends Nov. 30.

Philip Klotzbach and William Gray of Colorado State University now expect nine of the named storms to become hurricanes and five to grow into major hurricanes, meaning a category 3 through 5 on the Saffir-Simpson scale. Overall, the researchers predict a much more active season than the typical season between 1950 and 2000.

The announcement comes as Tropical Storm Edouard, the fifth tropical cyclone of the 2008 season, carried heavy rains and strong winds onto the upper Texas coast today. The tropical storm was just shy of hurricane strength when it came ashore. 

When a tropical cyclone (the generic name for a low-pressure system over tropical or sub-tropical waters) has surface winds that reach at least 39 mph (about 63 kph), the system is considered a tropical storm and gets christened with a name. Once the winds reach 74 mph (119 kph), the storm is considered a hurricane in the North Atlantic Ocean; a tropical cyclone in the Southwest Indian Ocean; and a typhoon in parts of the Northwest Pacific Ocean.

The latest forecast raises the team's early June prediction, which was 15 named storms, including eight hurricanes and four intense hurricanes.

The team points to warm sea-surface temperatures and low sea-level pressures over the tropical Atlantic in June and July, combined with an active early season in the deep tropics as driving the boost in their seasonal forecast numbers.

The forecast team also continues to warn of the considerably higher-than-average probability of at least one intense hurricane making landfall in the United States for the remainder of this year's hurricane season.

Here's the breakdown of the probability an intense hurricane will make landfall in different U.S. regions during the remainder of the hurricane season:

  • 67 percent: somewhere along the U.S. coastline
  • 43 percent: along the U.S. east coast, including the Florida peninsula
  • 42 percent: along the Gulf Coast from the Florida Panhandle westward to Brownsville, Texas

In 2004 and 2005, 13 major hurricanes formed in the Atlantic, with seven of them striking the U.S. coast. In 2004, Hurricanes Charley, Ivan and Jeanne made landfall in this country, followed in 2005 by Dennis, Katrina, Rita and Wilma.

Gray considers these years anomalies, but other climate scientists think the high number of hurricanes is influenced by global warming.

This is Colorado State team's 25th year of issuing early August forecasts. The team has correctly predicted an above- or below-average season in 21 of 24 years for named storms and 17 of 24 years for hurricanes in their early August forecasts.

Jeanna Bryner
Live Science Editor-in-Chief

Jeanna served as editor-in-chief of Live Science. Previously, she was an assistant editor at Scholastic's Science World magazine. Jeanna has an English degree from Salisbury University, a master's degree in biogeochemistry and environmental sciences from the University of Maryland, and a graduate science journalism degree from New York University. She has worked as a biologist in Florida, where she monitored wetlands and did field surveys for endangered species. She also received an ocean sciences journalism fellowship from Woods Hole Oceanographic Institution.