The Atlantic Ocean hurricane season this year is expected to be "active or extremely active," federal forecasters said Thursday.
The season, which runs from June 1 to Nov. 30, will bring 13 to 20 named storms, of which seven to 11 will be hurricanes, according to a forecast released Thursday by the National Hurricane Center, a division of the National Oceanic and Atmospheric Administration.
Three to six of those hurricanes will be major, the center said.
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 category 3 or greater, meaning it has sustained winds of at least 111 mph.
The seasonal average is 12 named storms and six hurricanes, three of them major.
Kathryn Sullivan, NOAA's acting administrator, said the forecast for an "active or extremely active" season is based on a variety of factors.
In 1995, the Atlantic Ocean began a period of greater tropical-storm activity with warmer-than-average sea-surface temperatures in the tropical Atlantic Ocean and the Caribbean Sea. Near-average sea-surface temperatures in the tropical Pacific Ocean means it is unlikely an El Niño feature will develop to suppress tropical activity in the Atlantic, Sullivan said.
The factors combined produce lower wind shear, lower air pressure and conductive wind patterns coming from Africa, all of which produce more and stronger hurricanes, she said.
The National Hurricane Center does not predict how many storms will hit land or where a tropical storm might hit along the East Coast or the Gulf Coast.
"Last year, to remind you, we had four land-falling storms: Hurricane Isaac in the Gulf Coast, Sandy in the Mid-Atlantic region, and tropical storms Beryl and Debby in northern Florida," Sullivan said in a conference call with media. Each threatened areas farther inland with flooding and wind.
Parts of Connecticut are still in various states of disrepair or construction after a back-to-back walloping in the past two years: Tropical Storm Irene in 2011 and Storm Sandy last year.
NOAA's lead seasonal hurricane forecaster, Gerry Bell, said the path of any storm depends on conditions at the time. Generally speaking, the factors that lead to this season being active or extremely active also increase the likelihood that storms will track farther west than in an average year, Bell said.
"And therefore, historically, we do tend to see more hurricane strikes along both the Gulf Coast and the Atlantic Coast as well as the entire region around the Gulf and the Caribbean Sea," Bell said.
Families, businesses and communities should get ready for the next big storm, said Joe Nimmich, the Federal Emergency Management Agency's associate administrator for response and recovery.
"Preparedness today can make a big difference down the line, so update your family emergency plan and make sure your emergency kit is stocked," Nimmich said in a prepared statement. "Learn more about how you can prepare for hurricane season at http://www.ready.gov/hurricanes."
Last Year's Results
In addition to the National Hurricane Center, another closely watched forecasting entity is Colorado State University, which is in its 30th year of predicting hurricanes in the Atlantic.
In early April, the Colorado forecasters said they expect 18 named storms, nine hurricanes and four major hurricanes during the 2013 season.
A year ago, the Colorado forecasters predicted the 2012 season would bring 10 named storms, four hurricanes and two major hurricanes in the Atlantic. Also last year, the National Hurricane Center predicted in May that the 2012 season would deliver nine to 15 named storms, or which four to eight would be hurricanes and one to three would be major hurricanes.
Last year, the hurricane season actually produced 19 named storms, 10 hurricanes and two major hurricanes.