"The probability of U.S. major hurricane landfall is estimated to be about 140 percent of the long-period average," said the scientists, who issue several seasonal hurricane forecasts each year "to satisfy the curiosity of the general public and to bring attention to the hurricane problem."
"Information obtained through March 2011 indicates that the 2011 Atlantic hurricane season will have significantly more activity than the average 1950-2000 season," they said April 6.
Hurricane Alex, the first named storm of the 2010 Atlantic hurricane season, hit northeast Mexico on June 30. (Image courtesy NOAA)
Hurricane season in the Atlantic begins on June 1 and ends November 30.
"We estimate that 2011 will have about nine hurricanes (average is 5.9), 16 named storms (average is 9.6), 80 named storm days (average is 49.1), 35 hurricane days (average is 24.5), 5 major (Category 3-4-5) hurricanes (average is 2.3) and 10 major hurricane days (average is 5.0)," the scientists said.
"We expect Atlantic basin Net Tropical Cyclone activity in 2011 to be approximately 175 percent of the long-term average."
The forecasters decreased their seasonal forecast slightly from early December, due to unusual warming in the eastern and central tropical Pacific and cooling in the tropical Atlantic.
"We expect current La Niña conditions to transition to near-neutral conditions during the heart of the hurricane season. Overall, conditions remain conducive for a very active hurricane season," they predicted.
The Atlantic basin has the largest year-to-year variability of any of the global tropical cyclone basins, say Klotzbach and Gray in their forecast.
While it is impossible to precisely predict this season's hurricane activity in early April, Klotzbach and Gray say they issue extended-range forecasts for seasonal hurricane activity because, "People are curious to know how active the upcoming season is likely to be, particularly if you can show hindcast skill improvement over climatology for many past years."
"Our new early April statistical forecast methodology shows strong evidence over 29 past years that significant improvement over climatology can be attained," they said, adding, "We would never issue a seasonal hurricane forecast unless we had a statistical model developed over a long hindcast period which showed significant skill over climatology."
This year's forecasts are funded by private and personal funds, said Klotzbach and Gray. They acknowledge the GeoGraphics Laboratory at Bridgewater State College in Massachusetts for their assistance in developing the United States Landfalling Hurricane Probability Webpage at: http://www.e-transit.org/hurricane.
According to these landfall predictions, in 2011 there is a 27 percent chance that one or more "Intense Hurricanes" will make landfall the New Orleans area of the Louisiana coast, which is still recovering from Hurricanes Katrina and Rita in 2005.
There is a 27 percent chance an Intense Hurricane will make landfall in Mobile, Alabama, a 23 percent chance of such a hurricane hitting land in Florida's Miami-Dade County, and a 20 percent chance in Galveston, Texas.
Due to a moderate La Niña, the 2010 Atlantic hurricane season was above average with the most number of named storms since 2005. Most of the damage in the 2010 season occurred in Mexico. Due to the prevailing atmospheric steering currents and the placement of the jet stream, most hurricanes remained away from the United States. No hurricanes struck the country, compared to the average of two.
Copyright Environment News Service (ENS) 2011. All rights reserved.