In their forecast for October and November, researchers Philip Klotzbach and William Gray said there would be four more named tropical storms from which two would become hurricanes, one of them major.
"Our well above-average prediction for October-November activity is largely due to the emergence of a now moderate La Nina event during the last two months," the report said, referring to a process over the Pacific Ocean that increases vertical wind shear, which strengthens Atlantic hurricanes.
This year there have been 13 named storms, with four becoming hurricanes -- two of them Category 3 or higher.
The report said in an average year, 78 percent of a year's worth tropical cyclonic activity had been experienced by the end of September, while this year that number was 84 percent.
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