The Atlantic Ocean is expected to churn out 18 named tropical storms, nine hurricanes and four major hurricanes during the season that stretches from June through November, according to a report released Wednesday by Colorado State University's Hurricane Forecast Team.

A named storm has sustained winds of at least 39 mph, and a hurricane has sustained winds of at least 74 mph. A major hurricane is a category 3 or greater, meaning it has sustained winds of at least 111 mph.

The forecast calls for a much more active season than the 20-year average of 12 named storms, six hurricanes and two major hurricanes.

There's also a good chance a major hurricane will come ashore — a 72 percent chance one will make landfall somewhere on the U.S. coastline and a 48 percent chance it will hit the East Coast, including Florida, the forecasters said.

A major hurricane hasn't made landfall in the U.S. since Hurricane Katrina in 2005.

"We've been very lucky," said William Gray, a co-author of the forecast.

Since 1999, many major hurricanes have swirled up the Atlantic, offshore, and spun north without causing damage to the U.S., Gray explained.

"The tropical Atlantic has anomalously warmed over the past several months, and it appears that the chances of an El Niño event this summer and fall are unlikely," Phil Klotzbach, co-author of the forecast, said in a prepared statement. "Typically, El Niño is associated with stronger vertical shear across the tropical Atlantic, creating conditions less conducive for storm formation."

Hurricane forecasts are based on a variety of conditions, such as the Atlantic basin's sea-surface temperatures.

Last year, there were two major hurricanes: Sandy, which was a category 3 at its most intense wind speed when it hit Cuba, and Hurricane Michael, which stayed in the open ocean.

The forecast for the Atlantic Ocean comes less than two months before the start of hurricane season, from June 1 through Nov. 30.

Colorado's forecast is one of two closely watched predictions for the hurricane season. The other is that of the National Hurricane Center, a division of the National Oceanic and Atmospheric Administration, which generally releases its forecast in late May.

Houston-based ImpactWeather released its forecast last month, predicting 16 to 20 named storms this year, compared with 19 actual named storms last year. ImpactWeather predicted seven to nine hurricanes overall, compared with 10 last year. ImpactWeather forecasts weather for corporate clients in the energy and utility industries, among others.

Colorado State University is in its 30th year of forecasting the Atlantic hurricane season. A year ago, the Colorado forecasters predicted the 2012 season would bring 10 named storms, 4 hurricanes and 2 major hurricanes in the Atlantic. Last year, the hurricane season actually produced 19 named storms, 10 hurricanes and two major hurricanes.

"It was a crazy year," Gray said. "An El Niño looked to be coming on last year, that's why we kept the numbers lower, and then as we got into August the whole thing just faded out. Instead of the warm water in the Eastern Equatorial Pacific that was coming on, it just stopped coming on and started to get cold again, and that affected the season, too."