Despite two unusual tropical storms forming in May, forecasters at Colorado State University think only two major hurricanes could form in the Atlantic Basin during a tropical storm season that isn’t expected to be as active as recent summers.
In their forecast released earlier today, CSU forecasters Phil Klotzbach and William Gray predicted that 13 named tropical storms with winds of at least 39 mph (62 kph) could form before hurricane season ends November 30. The forecast team thinks five of those storms could evolve into hurricanes with winds of at least 74 mph (118 kph). And two hurricanes could intensify into major storms with winds exceeding 110 mph (176 kph).
The Atlantic Basin includes the Caribbean Sea, the Gulf of Mexico and the Atlantic Ocean.
The two storms that formed in May — Alberto and Beryl — are included in the total predicted for the 2012 season.
The formation of two tropical storms before June 1 “has very little bearing on the rest of the hurricane season,” Gray and Klotzbach wrote. The forecasters noted that, before this year, two storms had formed before June only twice — in 1887 and 1908. The summer of 1887 was an active hurricane season with 19 tropical storms, while 1908 was less active with 10 storms.
If the summer of 2012 approximates the CSU forecast, it will be a quieter hurricane season than the recent past. Since 1995, hurricane seasons have tended to be very active, with an average of about 15 named storms, eight hurricanes and four major hurricanes forming each season.
Jeff Masters, director of the website Weather Underground, said water temperatures in the Atlantic are a little cooler than recent years, and this could reduce the number of tropical storms that form. Hurricanes draw their power from warm seawater near the surface that has been heated to at least 80 degrees Fahrenheit (about 27 degrees centigrade).
Masters noted that winter winds in the tropical Atlantic Ocean — where hurricanes most often form in the summer — were stronger than usual. These strong winter winds caused cooler water to be brought to the surface, so it will take longer for the water to warm up enough to fuel hurricanes.
“I wouldn’t be surprised if we didn’t see another tropical storm until August,” Masters said.