December 18, 2005

Five Major Hurricanes Expected in 2006

Seventeen named storms could strike the Atlantic basin next year, with nine developing into hurricanes, if predictions by William Gray and Philip Klotzbach of Colorado State University based in Ft. Collins come true. They forecast five major hurricanes with winds of at least 111 miles per hour.

In their report, “Extended Range Forecast of Atlantic Seasonal Hurricane Activity and U.S. Landfall Strike Probability for 2006,” Gray and Klotzbach forecast an 81 percent probability of at least one major hurricane making landfall along the U.S. coastline, with a 64 percent probability that such a storm will hit the East Coast, including the Florida peninsula. There is a 47 percent probability that a major hurricane will hit the Gulf Coast, from the Florida Panhandle westward to Brownsville, Texas.

Still, the likelihood of hurricanes making landfall with the frequency of the past two years is “very low,” according to the scientists. “It is rare to have two consecutive years with such a strong simultaneous combination of high amounts of major hurricane activity together with especially favorable steering flow currents. The historical records and the laws of statistics indicate that the probability of seeing another two consecutive hurricane seasons like 2004-2005 is very low,” the report said.

The report, part of Colorado State University’s Tropical Meteorology Project, cautions that there is “no physical basis” that links hurricane intensity or frequency to global mean surface temperature changes of less than 0.5 degrees centigrade.

The increase in Atlantic basin hurricanes across the past 11 years, the report indicated, is a result of an increased strength the past few decades in global oceanic circulation, driven by changes in salinity.

“Seasonal and monthly variations of sea surface temperature within individual storm basins show only very low correlations with monthly, seasonal and yearly variations of hurricane activity,” Klotzbach and Gray noted. “Other factors such as tropospheric vertical wind shear, surface pressure, low level vorticity, mid-level moisture, etc. play more dominant roles in explaining hurricane variability than do surface temperatures.”

For more information, visit http://
hurricane.atmos.colostate.edu/Forecasts.