First, a review of the 2009 season (graphic courtesy NHC below). 2009 was a below-average year with just 9 named storms, 3 hurricanes, and 2 major hurricanes. The long-term average is 9.6 named storms, 5.9 hurricanes, and 2.3 major hurricanes. Only Tropical Storm Claudette (in August) and Hurricane Ida (in November) had significant impacts on the continental U.S., while Hurricane Bill paralleled the eastern seaboard, bringing only high surf and some coastal erosion (though it did impact the Canadian Maritimes as a strong tropical storm).
So what about 2010? The CSU experts expect that 2010 will definitely not be another 2009. In fact, they say 2010 will have "significantly more activity than the average 1950-2010 season." With El Nino weakening and expected to be neutral by early in hurricane season, anomalously high sea surface temperatures already showing up in the hurricane-generating waters of the Atlantic, and weaker trade winds that would inject dry air into eastern Atlantic storms as they form, it is expected to be a much different year than last.
Their latest prediction is for 15 named storms (56% above average), 8 hurricanes (36% above average), and 4 major hurricanes (average is 2.3). They go on to predict the probabilities of a major hurricane (category 3 or higher) making landfall on a U.S. coastline at 69% (130% of the long-term average) and a 58% chance of a major hurricane striking the Caribbean (average is 42%).
Citing similar conditions, a slightly more dire forecast was made yesterday by Accuweather Hurricane Forecaster Joe Bastardi, who predicted 7 landfalls, 5 of which would be hurricanes and 2-3 of which would be major hurricanes.
Changes instituted by the National Hurricane Center for 2010 include additional lead time for watches and warnings to be issued (adding 12 hours to each - 48 hours in advance of landfall for a watch and 36 hours in advance for a warning), as well as adjusting the Saffir-Simpson scale to categorize a storm based on sustained wind speed only.
Links of interest: