WSI Corp.'s updated 2009 hurricane season forecast now calls for 10 named storms, five hurricanes, and two intense hurricanes (category 3 or greater), a slight reduction from the previous forecast of 11 named storms, six hurricanes, and two intense hurricanes.

The forecast numbers were reduced due to the unfavorable wind shear environment across the tropical Atlantic, which is driven by the recent development of a new El Nino event in the tropical Pacific. The impacts of the El Nino event have emerged more quickly than originally expected, resulting in reduced expectations for the upcoming season. The 2009 forecast numbers remain quite close to the long-term (1950-2008) average of 9.8 named storms, 6.0 hurricanes, and 2.5 intense hurricanes, but are significantly lower than the numbers from the relatively active seasons of the past 15 years.

The 2009 WSI tropical forecast comes on the heels of a successful 2008 forecast. The WSI December forecast values of 14 named storms, seven hurricanes, and three intense hurricanes were slightly smaller than the final observed 2008 values of 16/8/5. The subsequent updates improved the forecast further, as the April 2008 updated forecast values of 14 named storms, eight hurricanes, and four intense hurricanes were the most accurate among the publicly available forecasts issued last spring.

"Ocean temperatures in the tropical Atlantic remain quite cool relative to the temperatures during the last 15, more tropically active years," said WSI seasonal forecaster Todd Crawford. "Further, the new El Nino event continues to strengthen, resulting in an unfavorable wind shear environment across the tropical Atlantic. The early development of this enhanced wind shear along with the relatively cool tropical Atlantic temperatures will almost certainly result in a less-active season then last year, and could potentially result in an unusually quiet season. We have reduced our forecast numbers slightly to account for the impacts of the new El Nino event, and the fact there have been no early-season storms through mid-July."