Colorado State University scientists Phil Klotzbach and William Gray unveiled a new Caribbean hurricane forecast as part of their 2010 Atlantic Basin hurricane forecast update on Wednesday.

In addition to increasing all their Atlantic Basin forecast numbers by 20 to 25 per cent over their 7 April predictions, the duo predicted an Accumulated Cyclone Energy index for the Caribbean to be as high this year as the record-breaking Atlantic hurricane season of 2005. The forecast ACE measure for the Caribbean in 2010 is 58. In comparison, the observed ACE in the Caribbean in 2009 was four.

For the whole Atlantic Basin, their forecast on named storms increased from 15 to 18; the forecast number of hurricanes increased from eight to 10; and the forecast number of major hurricanes of Category 3 strength or above increased from four to five.

The long-term annual averages for a hurricane season are 9.6 named storms, 5.9 hurricanes and 2.3 major hurricanes.

“We have increased our forecast from early April due to a combination of a transition from El Niño to currently-observed neutral conditions and the continuation of unusually warm tropical Atlantic sea surface temperatures,” the duo wrote in their report.

Klotzbach and Gray predict that La Niña conditions will develop in the equatorial Pacific Ocean by the time of the most active part of the hurricane season arrives in August.

“The expected trend towards weak La Niña conditions should lead to reduced levels of vertical wind shear compared with what was witnessed in 2009,” the forecast report stated.

Accumulated Cyclone Energy is a measure that takes into account the number, strength and duration of tropical cyclones that reach at least tropical storm strength. Klotzbach and Gray now forecast of an Atlantic Basin ACE of 185 this year, up from 150 in their 7 April forecast. Any measure over 150 for the Atlantic Basin is considered a hyperactive season. 

The scientists also forecast a 65 per cent probability of at least one major hurricane tracking into the Caribbean, considerably higher than the 42 per cent average for the last century.

“Major hurricanes cause 80-85 per cent of normalised hurricane damage,” the forecast report noted.

Klotzbach and Gray’s updated forecast calling for a very active Atlantic Basin hurricane season follows several others calling for the same. Last week, the US Climate Prediction Center, part of the National Oceanic and Atmospheric Administration, forecast 14 to 23 named storms, eight to 14 hurricanes and three to seven major hurricanes.  The CSU scientists’ forecast numbers fall close to the centre of all of those ranges.

Joe Bastardi, AccuWeather.com’s chief meteorologist and hurricane forecaster, predicted 16 to 18 named storms, 10 to 11 hurricanes and five major hurricanes, numbers very similar or the same as Klotzbach’s and Gray’s.