The final “preseason” forecast from top experts at Colorado State University, released Friday morning, again calls for an “above-average 2013 Atlantic basin hurricane season.”
A total of 18 named tropical storms are forecast to form, of which eight should be hurricanes. This is a slight reduction from Colorado State’s previous forecasts, which called for nine hurricanes.
A typical year, based on weather records that go back to 1950, has 12 tropical storms, of which seven are hurricanes. A tropical storm has sustained winds of 39 mph; it becomes a hurricane when its winds reach 74 mph.
The Atlantic hurricane season started June 1 and lasts until Nov. 30. So far this year, four tropical storms have formed in the Atlantic, but no hurricanes, according to the National Hurricane Center. August and September are the two most active months for hurricanes in the Atlantic.
This prediction was released by meteorologists Philip Klotzbach and William Gray at Colorado State’s Tropical Meteorology Project.
Why the drop in the number of predicted hurricanes? “While the tropical Atlantic remains warmer than normal, it has cooled somewhat in the eastern portion of the basin,” Klotzbach said. Warm water provides the fuel that helps a hurricane form.
Nevertheless, an active season still looks probable: “It appears that the chances of an El Nino event this summer and fall are unlikely,” he says.”Typically, El Nino is associated with stronger vertical shear across the tropical Atlantic, creating conditions less conducive for storm formation.”
Colorado State was the first organization to issue seasonal hurricane forecasts, and is now in its 30th year of issuing these forecasts.