With a dozen tropical storms already named this year, WSI Corp. forecasters say they expect a total of 18 named storms, including 10 hurricanes, six of them intense (Category 3 or stronger), to form before the 2010 Atlantic hurricane season ends Nov. 30.

WSI’s final tropical update of the year calls for one more intense hurricane than the forecaster predicted last month (see Daily GPI, Aug. 25) “due to the somewhat surprising attainment of major hurricane status by Julia and Karl last week,” according to WSI Chief Meteorologist Todd Crawford. At the peaks of their strength last week, Karl and Julia each attained Category 4 status.

The Northeast continues to be under an enhanced risk of hurricane landfall, according to WSI.

“After a relatively slow start, the tropical season has gone ‘supernova’ during the past few weeks, with five major hurricanes occurring within the last three weeks, a historically unprecedented event. Although the primary storm track has been for storms to approach the eastern U.S. seaboard before recurving out to sea, there are indications that this pattern is changing and that the danger to the U.S. coastline may be increasing going forward,” Crawford said.

On Tuesday the season’s sixth hurricane, Igor, passed near Cape Race, NF, with maximum sustained winds of 75 mph, according to the National Weather Service’s (NWS) National Hurricane Center. Earlier this month Hurricane Earl delivered glancing blows to North Carolina’s Outer Banks and the New England coastline. Karl reached hurricane status in the Bay of Campeche before making landfall last Friday near Veracruz, Mexico, and Julia kept well off the East Coast. This year’s early hurricanes — Alex and Danielle — also posed little threat to energy interests in the Gulf of Mexico and on the U.S. mainland.

Tropical Storm Lisa, the season’s 12th named storm, was moving slowly northward over the far eastern tropical Atlantic on Tuesday, about 530 miles west-northwest of the Cape Verde Islands, with maximum sustained winds of 45 mph, NWS said.

WSI’s revised 2010 forecast numbers are well above the long-term (1950-2009) averages of 10 named storms, six hurricanes and two intense hurricanes and slightly above the averages from the more active recent 15-year period (1995-2009) of 14/eight/four.

Forecasters at the National Oceanic and Atmospheric Association have said they expect a La Nina event — an unusual cooling of ocean surface temperatures off the western coast of South America — to bring “significant” hurricane activity this year (see Daily GPI, Aug. 6). Colorado State University forecasters have predicted an active hurricane season and said they see a “well above-average probability” of a major hurricane making landfall in the United States and the Caribbean (see Daily GPI, Aug. 5). AccuWeather.com Chief Long Range Forecaster Joe Bastardi has said 2010 could be one of the most active seasons on record (see Daily GPI, May 20).

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