(CNN) - The Atlantic hurricane season starts next week, and forecasters say it could be a busy one.
Forecasters at the Climate Prediction Center are predicting 11 to 17 named storms this season, which runs from June 1 to Nov. 30.
Of those storms, five to nine are expected to be hurricanes, while two to four of those will become major hurricanes.
Those numbers include tropical storm Arlene, which formed in the eastern Atlantic last month.
A "major hurricane" is categorized as a storm with winds of at least 111 miles an hour.
Forecasters say the above-average prediction is due to several factors, including a weak or non-existing El Nino, above-average water temperatures in the Atlantic and average or weaker-than-average vertical wind shear.