MIAMI, Aug 24 (Reuters) - Weather Service International trimmed its forecast for the 2010 Atlantic hurricane season on Tuesday but still expected a very busy year with double the average chance a hurricane would hit the Northeast U.S. Coast.
The Massachusetts company known as WSI said atmospheric patterns and warm ocean temperatures had put the U.S. coastal region from the Outer Banks of North Carolina northward to Maine under a significantly increased threat this year.
"Our model suggests that the threat to the Northeast Coast this season is on par with that in Florida and the Gulf coastal states," the company said in a statement.
WSI said it expected 18 named storms, with 10 of those strengthening into hurricanes during the six-month Atlantic-Caribbean storm season that began on June 1.
It expected five of those would grow into major hurricanes with winds of at least 111 miles per hour (178 km per hour), making them category 3 or higher on the five-step Saffir-Simpson scale of hurricane intensity.
The forecast was lowered slightly from a July forecast of 19 storms and 11 hurricanes, with five major storms.
But it was still well above the long-term average of 10 storms, six hurricanes and two major hurricanes.
The Atlantic hurricane season has so far seen fewer storms than expected, because pockets of dry air and shearing winds hindered their formation.
But as the season heads into its traditionally busiest phase from mid-August to October, the atmosphere is quickly becoming more favorable for tropical development, said WSI's chief meteorologist, Dr. Todd Crawford.
"Atlantic sea surface temperatures remain at record warm levels, even warmer than the freakishly active season of 2005," Crawford said.
"(We) have reduced our numbers a bit to account for the lagged start, but are still just as bullish as ever on the remainder of the season," he said.
There have been four named storms so this season, Alex, Bonnie, Colin and Danielle, and another disturbance near the African Coast was expected to become Tropical Storm Earl by Wednesday. Alex and Danielle strengthened into hurricanes and Danielle was forecast to become the season's first major hurricane, though it did not threaten land.
Seasonal forecasts cannot predict the impact of any single storm, but can give farmers, energy interests and insurers a general idea of what to expect in the months ahead. (Reporting by Jane Sutton; Editing by Marguerita Choy)