NU Online News Service, Dec. 7, 1:41 p.m. EST
Chances are next year will be another active hurricane season in the Atlantic if an El Niño does not develop, say forecasters at Colorado State University.
The forecast team of Philip Klotzbach and William Gray released its early hurricane season forecast for 2012, saying that it is dispensing with the usual numerical forecast for the number of storms. Instead, Klotzbach and Gray issued their forecast in terms of the probabilities "of the key factors influencing the hurricane season."
The reason for the change, they say, is the difficulty forecasters have in determining whether an El Niño will occur in the Pacific, which impacts the Atlantic hurricane season.
The team says there is a 45 percent chance that climate conditions that have persisted since 1995 will continue along with no El Niño development in the Pacific. These conditions include warmer water temperatures in the tropical Atlantic and reduced vertical wind shear—conducive conditions for hurricane formation.
Should that be the case, hurricane activity would be 140 percent of the average season, which would be characterized as 12 to 15 named storms, seven to nine hurricanes and up to four major hurricanes (Category 3, 4 or 5 with sustained winds of 111 mph and greater), the forecasters say.
The team says there is a 30 percent chance that Atlantic wind circulation remains unchanged and a significant El Niño occurs, which would reduce the tropical-cyclone season to approximately 75 percent of the average season. That would be 8 to 11 named storms, three to five hurricanes and one or two major hurricanes.
There is a 15 percent chance that current Atlantic wind conditions could become unusually strong, and no El Niño occurs, which would lead tropical-cyclone activity of up to 180 percent of average hurricane season—about 14 to 17 storms, 9 to 11 hurricanes and four to five major hurricanes.
And the forecasters say there is a 10 percent chance that current Atlantic wind conditions weaken and a significant El Niño develops, which would reduce the tropical-cyclone activity to 40 percent of the average season—five to seven storms, two to three hurricanes and possibly one major hurricane.
For 2011, the CSU forecast team had predicted that the hurricane season would be well above average. In June the team called for 16 named storms, nine hurricanes and five major hurricanes. The season produced 19 named storms, seven hurricanes and three major hurricanes.
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