Not much has changed since Colorado State University hurricane researchers last issued tropical predictions in April. Phil Klotzbach and Dr. William Gray announced Thursday morning that they are maintaining the earlier forecast, calling for a very active 2007 Atlantic Hurricane Season with a 74 percent chance of a major storm making landfall on the U.S. coastline.

The team is calling for 17 named storms forming in the Atlantic basin between now and Nov. 30. Nine of the storms are expected to become hurricanes with five becoming intense hurricanes (Saffir-Simpson category 3-4-5) with sustained winds of 111 mph or greater.

In a press release, Klotzbach stated, “We expect an above-average hurricane season with ENSO conditions on the cool side, which will help increase the likelihood of major storm activity in the Atlantic.” Now lead author of the forecast, he added, “El Niño conditions during the summer and fall — similar to those that developed in 2006 — tend to decrease Atlantic hurricane activity by increasing vertical wind shear across the area where Atlantic tropical cyclones develop.”

No hurricanes made landfall in the U.S. last year. There were 10 named storms, five hurricanes and two major hurricanes. Long-term averages are 9.6 named storms, 5.9 hurricanes and 2.3 intense hurricanes per year, according to the Colorado State forecast team.

They expect tropical cyclone activity in 2007 to be 185 percent of the average season. By comparison, 2005 witnessed tropical cyclone activity that was around 275 percent of the average.

Klotzbach and Gray restated probabilities for a major hurricane making landfall on U.S. soil:

• A 50 percent chance that a major hurricane will make landfall on the U.S. East Coast, including the Florida peninsula (the long-term average is 31 percent).

• A 49 percent chance that a major hurricane will make landfall on the Gulf Coast from the Florida panhandle west to Brownsville, Texas (the long-term average is 30 percent).

The team also predicted above-average major hurricane landfall risk in the Caribbean.

The 2006 season was only the 12th year since 1945 the United States experienced no hurricane landfalls. Since then, there have been only two consecutive years where there were no hurricane landfalls: 1981-1982 and 2000-2001.

“There were a lot of challenges in 2006 that we didn't expect such as a late-developing El Niño, which causes increased vertical wind shear and results in less tropical cyclone activity,” stated Gray, who began forecasting hurricane seasons at Colorado State 24 years ago.

Klotzbach and Gray expect continued warm tropical and north Atlantic sea-surface temperatures this year, which has been prevalent in most years since 1995, as well as neutral or weak La Niña conditions — a recipe they say greatly enhances Atlantic basin hurricane activity.

According to the team, these factors are similar to conditions that occurred during the 1952, 1954, 1964, 1966, 1995 and 2003 seasons. The average of these six seasons had well above-average activity, and Klotzbach and Gray predict the 2007 season will have activity in line with the average of those six years.

“We are in a new era for storms that is part of a natural cycle,” Gray said. “We’ve had an upturn of major storms in the Atlantic since 1995. This active cycle is expected to continue for another decade or two at which time we should enter a quieter Atlantic major hurricane period like we experienced during the quarter century periods of 1970-1994 and 1901-1925. These changes in storm activity are not caused by human-induced global warming but by natural forces.”

The Colorado State hurricane forecasters have previously said the hurricane seasons of 2004 and 2005 were anomalies: Florida and the Gulf Coast were ravaged by four landfalling hurricanes each year. Hurricanes Charley, Frances, Ivan and Jeanne caused devastating damage in 2004 followed by Dennis, Katrina, Rita and Wilma in 2005.