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WASHINGTON (CNN) -- The approaching 2008 Atlantic hurricane season is likely to be above normal, with up to 16 named storms and up to five major hurricanes, the National Oceanic and Atmospheric Administration said Thursday, citing climate conditions.

The outlook issued by the NOAA's Climate Prediction Center calls for "considerable activity," with a 65 percent probability of an above-normal season, and an overall 90 percent chance the season will be normal or above, the agency said in a news release.

A "normal" season has 11 named storms, six hurricanes and two major hurricanes of Category 3 or higher on the Saffir-Simpson scale of hurricane intensity.

For 2008, NOAA said, there is a 60 to 70 percent chance of 12 to 16 named storms.

"The outlook is a general guide to the overall seasonal hurricane activity," said Conrad Lautenbacher, undersecretary of commerce for oceans and atmosphere and a NOAA administrator, in the news release. "It does not predict whether, where or when any of these storms may hit land. That is the job of the National Hurricane Center after a storm forms."
On Thursday, the agency urged residents of coastal states to be prepared for the season, which begins June 1. It said the outlook is based in part on lingering effects of La Niña, a phenomenon in which surface waters in the eastern Pacific are colder than normal.

Storms aren't named until they are designated tropical storms, with sustained maximum winds of at least 39 mph. Tropical storms become Category 1 hurricanes when their sustained winds reach 74 mph and major Category 3 hurricanes when their winds reach 111 mph.

The NOAA's outlook falls in line with predictions issued by the noted Colorado State University hurricane forecasting team.

In a forecast issued April 9, the CSU team predicted 15 named storms, an increase from its December number of 13. Of those, it predicted, eight will become hurricanes and four will grow into major hurricanes.

The team calculated a 69 percent chance that at least one major hurricane will make landfall on the U.S. coast. In addition, the team said, there is an above-average major hurricane landfall risk in the Caribbean.

The predictions came after calmer-than-normal seasons of 2006 and 2007.

But "we believe that the Atlantic basin is still in an active hurricane cycle," William Gray, who co-heads the CSU team, said in December. "This active cycle is expected to continue at least for another decade or two. After that, we're likely to enter a quieter Atlantic major hurricane period."

The 2007 season was the weakest in five years, despite two hurricanes making landfall at Category 5 intensity, according to the National Hurricane Center. Hurricanes Dean and Felix hit Mexico and Nicaragua respectively, marking the first time in history that two Category 5 storms made landfall in the same season since records started being kept in 1851, according to the National Hurricane Center.

Of 2007's six hurricanes, only one -- Humberto -- made landfall in the United States, striking the upper Texas Gulf Coast on September 13. Humberto was blamed for one death.

In 2006, there were nine named storms and five hurricanes. None made landfall in the United States. Gray's team that year had predicted 17 named storms and nine hurricanes, five of them major.