The number of 2012 Atlantic hurricanes will be below average this season due to a cooling of tropical waters and the potential development of El Nino conditions, US forecasters said Wednesday.

The Colorado State University forecast team predicted 10 named storms during the hurricane season from June 1 to November 30.

Four of the storms are expected to achieve hurricane strength and two of those are expected to be major hurricanes, with sustained winds of 111 miles (178 kilometers) per hour or greater.

"We have witnessed cooling of the tropical Atlantic during this past winter, and there is a fairly high likelihood that an El Nino event will develop this summer," said Phil Klotzbach of the CSU Tropical Meteorology Project.

He said that El Nino -- which involves a warming in tropical Pacific Ocean waters -- is associated with stronger vertical shear across the tropical Atlantic, creating "conditions less conducive for storm formation."

"Still, all vulnerable coastal residents should make the same hurricane preparations every year, regardless of how active or inactive the seasonal forecast is," he added. "It takes only one landfall event near you to make this an active season."

The new forecast relies on 29 years of historical data and takes into account global oceanic and atmospheric conditions such as El Nino, Atlantic basin sea surface temperatures, and sea level pressures which preceded active or inactive hurricane seasons.

"Despite this below-average forecast, we remain -- since 1995 -- in a favorable multi-decadal period for enhanced Atlantic Basin hurricane activity, which is expected to continue for the next 10-15 years or so," said CSU project founder William Gray.

The team predicted that tropical cyclone activity in 2012 will be about 75 percent of the average season, or around half the level of 2011.

It said there is 42 percent chance that at least one major hurricane will make landfall on the US coastline, compared with the long-term average probability of 52 percent.

The forecasters cited a 24 percent chance that a major hurricane will make landfall on the US east coast, including Florida, and the same odds for the US Gulf of Mexico coast.