June 2, 2009 — Cooler than normal temperatures in the tropical Atlantic Ocean and a greater potential for a weak El Nino during the bulk of hurricane season led Colorado State University forecasters Phil Klotzbach and William Gray Tuesday to call for a slightly below average hurricane season.
This is a change from their early April forecast.
"We believe that there is a slightly greater chance of a weak El Nino developing this summer/fall than there was in early April," Gray said in a press release issued Tuesday. "El Nino conditions would likely increase levels of vertical wind shear and decrease Atlantic hurricane activity."
Additionally, Klotzbach and Gray said an unusual cooling of sea surface temperatures in the tropical Atlantic over the past few months has occurred. They said "cooler waters are associated with dynamic and thermodynamic factors that are less conducive for hurricane formation."
The team now thinks that 11 named storms will form in the Atlantic basin during the June 1 to Nov. 30 hurricane season. They predict five will become hurricanes. Of those five, they expect two to develop into major hurricanes with sustained winds of 111 mph or greater.
The scientists reduced their forecast from April's prediction of 12 named storms, six hurricanes and two major hurricanes.
Long-term averages stand at 9.6 named storms, 5.9 hurricanes and 2.3 major hurricanes per year.
For the first time, the Colorado State team is predicting landfall probabilities for the Caribbean and Central America. This season, the forecast team expects a 39 percent chance of a major hurricane tracking into the Caribbean, which is slightly lower than the long-term average of 42 percent.
The team also updated its U.S. landfall probabilities. The press release indicates that these probabilities are calculated based upon 20th century landfall statistics and then adjusted by the latest seasonal forecast.
"The probability of a major hurricane making landfall along the U.S. coastline is 48 percent compared with the last-century average of 52 percent," Klotzbach said.
Currently observed climate factors are similar to conditions that occurred during 1959, 1960, 1965, 2001, and 2002 seasons. The average of these five seasons had slightly below-average activity, and Klotzbach and Gray predict the 2009 season will have activity in line with the average of these five years.
Gray and Klotzbach advise coastal residents not to change their hurricane preparedness measures because of a less active seasonal forecast since major hurricanes can devastate coastal communities in less active seasons.
Locally, V.I. Territorial Emergency Management Agency Director Mark Walters said in a press release Monday that the community needs to be ready for any disaster.
"These three simple steps that will help ensure your safety and well-being in the event of a disaster," Walters said. "Put together an emergency supply kit, make a family emergency plan and stay informed about bad weather headed your way."
An emergency supply kit should include items such as fresh water, a three-day supply of non-perishable food, flashlights, batteries, a radio, dust masks, personal hygiene items, cleaning supplies and other necessities.
Families should make an emergency plan, in advance, of how they will contact one another in the event they are apart when disaster strikes.
Walters advised residents to stay tuned by radio, television and other media for the latest news about storms headed this way and where to evacuate in the event of a major storm.
"VITEMA is doing its part to be prepared by making improvements to its emergency operation centers, re-aligning the organization to better meet the needs of responders and the community, and outfitting shelters with emergency generators to ensure their continuous operations," Walters said. "The community must also do its part."
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