MIAMI, Florida (CNN) -- The National Hurricane Center's latest forecast for the 2006 season calls for more Atlantic hurricanes than usual, but not as many as seen over the past three years and fewer than predicted in the NHC's initial estimate in May.
NHC director Max Mayfield said he expects 12 to 15 named storms, with seven to nine gaining hurricane status. Of those, three or four will grow to Category 3 strength or greater, Mayfield said.
Hurricane Katrina slammed into the U.S. Gulf Coast in late August 2005.
A Category 3 hurricane is classified as a major hurricane on the Saffir-Simpson scale, with sustained winds of 110 mph or more.
The 2005 season saw a record 28 named storms, including 15 hurricanes. Three named storms had been recorded by mid-August 2006.
Early to middle September is considered the peak of the season that runs from June 1 to the end of November.
Gerry Bell, lead forecaster for the National Oceanic and Atmospheric Administration, said water temperatures, wind patterns and other factors that guide storm development are not the same as a year ago.
"The combination of climate factors that would normally produce an extremely active season that were in place for the last three years, those factors have dissipated," he said.
An active hurricane era began in 1995 and should last about 25 years, Bell said.
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"Since '95, nine of the last 11 hurricane seasons have been above normal and this year will probably make it 10 out of the last 12," he said.
The 25 years leading to 1995 saw a below-average cycle, with only three hurricane seasons above normal, he said.
Bell said global warming was important but there was no conclusive evidence that the "greenhouse effect" caused the current string of overactive hurricane seasons.
"The jury is still out and a lot of work is being done now to try and establish whether there are real global trends," Bell said.
Mayfield said he remains concerned about a lack of awareness and preparedness among Americans living in areas vulnerable to hurricanes.
He quoted a survey of people living along the United States coastline from Texas to Maine that found more than half do not feel vulnerable to hurricanes nor have a family disaster plan or hurricane survival kit.
Mayfield said history shows "people who had a hurricane plan did a lot better than those who did not have a plan."
Another noted forecast -- prepared by a Colorado State University research team -- also was recently revised and is almost identical to the one just issued by the NHC.