Forecaster expects busy Atlantic hurricane season

MIAMI (Reuters) - The 2008 Atlantic hurricane season will likely be a busy one with 15 tropical storms, of which eight will turn into hurricanes, the noted Colorado State University forecasting team said on Tuesday.

The prediction from the research team founded by hurricane forecasting pioneer William Gray was unchanged from the one CSU issued in April, which called for four of the eight hurricanes to become "major" storms, the most destructive type, with sustained winds of more than 110 miles per hour (177 kph).

The average hurricane season produces roughly 10 tropical storms and six hurricanes.

The CSU forecast said warm Atlantic sea temperatures, along with low pressure at the ocean's surface and low levels of vertical wind shear, would contribute to an above-average season.

Hurricanes draw energy from warm water, while vertical wind shear, a difference in wind speeds at different altitudes, can disrupt nascent storms.

"Conditions in the tropical Atlantic look quite favorable for an active hurricane season," lead forecaster Phil Klotzbach said in a statement.

The official six-month Atlantic hurricane season began on Sunday. The first cyclone of the year, Tropical Storm Arthur, formed a day earlier off the coast of Belize and moved quickly inland.

The storm lasted less than a day before weakening to a tropical depression, but it still forced Mexico to shut two of its three main crude oil ports because of rough seas.

Arthur drenched southern Mexico, Belize and Guatemala, threatening deadly flash floods and mudslides.

Klotzbach said forecasters were closely monitoring sea temperatures in the eastern Pacific for the development of El Nino, a warming of ocean water that can dampen hurricane activity in the Atlantic.

"At this point, we do not believe that an El Nino will develop by late this summer," he said.

The CSU forecast called for a 69 percent chance that at least one major hurricane would hit the U.S. coast, well above the long-term average of 52 percent. It gave a 45 percent probability of a major hurricane on the East Coast and a 44 percent chance on the Gulf of Mexico coast.

Energy, insurance and commodities markets have tracked Atlantic storms closely since the catastrophic years of 2004 and 2005.

Four powerful hurricanes hit Florida in 2004, collectively causing $45 billion in damage. In 2005, Hurricane Katrina became the costliest natural disaster in U.S. history when it ravaged New Orleans and the Gulf coast, causing $80 billion in damage and killing 1,500 people.

That year saw 28 tropical storms and hurricanes, the highest number since recordkeeping began in 1851.

Researchers say the Atlantic basin entered a period of heightened hurricane activity around 1995 that could last for 25 to 40 years. Some suggest human-induced global warming may be contributing to more and stronger hurricanes, while others say the increased numbers are due to natural cycles.

(Reporting by Jim Loney; Editing by Doina Chiacu)