MIAMI - US forecasters predicted Thursday that this year's Atlantic hurricane season would produce a normal number of about nine to 15 tropical storms.
As many as four to eight of those storms could strengthen into hurricanes, according to the National Oceanic and Atmospheric Administration's initial outlook for the six-month storm season that officially begins June 1. One to three of those could become major hurricanes with top winds of 111 miles per hour or higher.
The weather phenomenon known as El Nino, which warms Pacific waters near the equator and increases wind shear over the Atlantic, may develop by the late summer or early fall and help suppress storm development, forecasters said.
This season got an early start when Tropical Storm Alberto formed Saturday off South Carolina. Alberto dissipated Tuesday over the Atlantic.
Forecasters name tropical storms when their top winds reach 39 miles per hour; hurricanes have winds of at least 74 miles per hour. The next named storm will be Beryl.
No major hurricane has made a US landfall in the last six years, since Hurricane Wilma cut across South Florida in 2005. US officials used Thursday's prediction to remind coastal areas about emergency preparedness.
August will mark the 20th anniversary of Hurricane Andrew's catastrophic landfall in South Florida as a Category 5 storm. The season that spawned Andrew started late and produced a total of just six named storms.
"Although this outlook suggests a less active season compared to recent years, the bottom line here is to prepare,'' said Robert Detrick, NOAA assistant administrator in the agency's Office of Oceanic and Atmospheric Research. "It takes just one major landfalling hurricane to make for a bad season.''
The seasonal average is 11 named storms, six hurricanes and two major hurricanes.
The 2011 hurricane season, one of the busiest on record with 19 named storms, produced Irene, one of the costliest storms in US history.
Hurricane season ends Nov. 30, and the peak period runs from August through October.