NOAA still expects "very active" hurricane season

He stressed the need for advance preparations regardless of the outlook. "People need to prepare for each and every hurricane season, regardless of this outlook or any other outlook," Bell said. "It only takes one hurricane to make for a disastrous year."

"It is equally disconcerting that our coastlines have built up considerably in the last few decades, and many more people are not in potential harm's way," he said.

Separately, the Colorado State University forecast team of Phil Klotzbach and William Gray issued their August forecast update. It's unchanged from their June 2 predictions: 18 named storms, of which 10 will become hurricanes, 5 of them reaching Cat. 3 strength. Their forecast includes landfall estimates: a 50 percent chance that a major hurricane will strike the U.S. East Coast, including Florida; a 49 percent chance of a major storm striking the Gulf Coast, and a 64 percent chance of a cat. 3 storm striking in the Caribbean and Central America. All these probabilities are well above the long-term averages.

Three major factors are still in place to generate this high level of storm formation, Bell said. The first is a continuing, multidecadal pattern of high storm activity that began in 1995.  "So we're 16 years into an active era that historically lasts 25 to 40 years," he said.

The second is a pattern of record-high sea surface temperatures in the tropical Atlantic Ocean. Those temperatures are currently running 2 to 3 degrees Fahrenheit above average. "The previous record warm year is 2005," Bell said.

Bell didn't point this out, but 2005 brought us Hurricanes Katrina and Rita (satellite image, top), and ended with a record 27 named strorms. In fact, the NHC ran out of names that season and had to employ Greek alphabet letters for the last six tropical storms, two of which became hurricanes.

The third factor Bell cited is the strengthening of the La Nina conditions in the eastern and central tropical Pacific Ocean. La Ninas tend to change wind patterns in the tropical Atlantic in ways that weaken the high-altitude winds that otherwise tend to cut off tropical storm development.

So far this season, there have been three tropical storms, only one of which has reached hurricane strength. Hurricane Alex went ashore in Mexico's Yucatan Peninsula (photo above) as a tropical storm on June 27, and again in northeast Mexico on June 30 as a Cat. 2 hurricane.

Tropical Storm Bonnie crossed the southern tip of Florida on July 23 with little impact. And Tropical Storm Colin weakened in the mid-Atlantic earlier this week. Remnants of the storm (satellite image, left) continue to cross the Atlantic. They are given a 50 percent chance of regaining tropical storm strength in the next 48 hours.

(PHOTO: Middle photo: Matamoros, Mex., by Adrian Del Angel/Agence France Press/Getty Images)