By Jane Sutton
MIAMI, May 31 (Reuters) - The Colorado State University hurricane research team renewed its forecast for an "above average" 2007 Atlantic storm season on Thursday and predicted 17 tropical storms, with nine growing to hurricane strength.
Of those, five would grow into major hurricanes of Category 3 or higher with winds over 110 mph (177 kph), the team founded by forecast pioneer William Gray said in its revised forecast.
The updated forecast issued on Thursday was unchanged from the team's April 3 forecast for the six-month storm season that starts on Friday.
The researchers said there was a 74 percent chance that at least one major hurricane would hit the U.S. coastline in 2007, with a 50 percent chance that would happen on the U.S. Atlantic Coast and a 49 percent chance on the Gulf of Mexico coast.
An average season brings 11 tropical storms, with six reaching hurricane wind speed of 74 mph (119 kph) and two growing into major hurricanes.
Other private and government weather researchers have also predicted a more active season than average. But so far none have forecast anything like a repeat of record-breaking 2005, when 28 tropical storms spawned 15 hurricanes, including Katrina which flooded New Orleans and parts of the Gulf coast.