Researchers at Colorado State University's Department of Atmospheric Science predict that there will be 12 named storms and six hurricanes in the Atlantic basin in 2009. Of the hurricanes, they say two will be intense hurricanes (Category three or above).
Philip Klotzbach and William Gray say the 2009 hurricane season will be on a par with the average 1950-2000 season. They estimate that the probability of a US major hurricane landfall is marginally higher than the long-term average.
The latest forecast – published on April 7 – is slightly lower than Klotzbach and Gray's initial estimate on December 10 2008, in which they predicted 14 named storms and seven hurricanes for 2009, of which three would be intense.
Klotzbach and Gray expect weak La Niña conditions to transition to neutral by the end of this year's hurricane season, and El Niño conditions to be weak. They say that if El Niño conditions develop for the 2009 hurricane season, this could increase levels of vertical wind shear, which would tend to decrease levels of Atlantic hurricane activity.
They add that their forecast reduction is partly the result of unexpected cooling of sea surface temperatures in the tropical Atlantic. Cooler waters are less conducive for an active Atlantic hurricane season.