More storms are expected during the coming Atlantic hurricane season which should be "near-normal," after three years of unusually low storm activity, US government scientists said on Friday.
The Atlantic could see 10 to 16 tropical storms, of which four to eight could become hurricanes, said the National Oceanic and Atmospheric Administration's (NOAA) Climate Prediction Center.
Between one and four of the storms could become major hurricanes of Category Three or higher on a scale of 1-5.
Wind speed in a Category Three hurricane reaches 111-129 miles per hour (178-208 kilometers per hour), with the potential to uproot trees and cause devastating damage to buildings and homes.
The end of the warming climate pattern El Nino and the arrival of the cooling trend in the equatorial Pacific known as La Nina could favour the increase in hurricane activity, said NOAA administrator Kathryn Sullivan. "We could be in for more activity than we have seen in recent years," she told reporters, but noted that the forecast "makes no prediction with respect to landfalls or tracks at this point."
The federal agency acknowledged some overall uncertainty in the forecast, and said its predictions were made with 70 percent likelihood.
"This is a more challenging hurricane season outlook than most because it's difficult to determine whether there will be reinforcing or competing climate influences on tropical storm development," said Gerry Bell, lead seasonal hurricane forecaster with NOAA's Climate Prediction Center.
Hurricane season begins June 1 and runs through November 30.
The 2015 season was considered below average with 11 tropical storms in the Atlantic, of which four became hurricanes, and two became major hurricanes. The long-term average, taken over the years 1981-2010, typically allows for 12 named storms, six hurricanes, and four major hurricanes.
NOAA will issue another, updated Atlantic hurricane forecast in early August, just before the storm season reaches its peak.
Pacific forecast
Forecasters also issued their outlook for the eastern Pacific and central Pacific basins, anticipating a near-normal season.
Between four and seven tropical cyclones are likely in the central Pacific.
The eastern Pacific hurricane outlook calls a 70 percent probability of 13-20 tropical named storms.
Six to 11 of those could become hurricanes, including three to six major hurricanes. Both long- and short-term temperature patterns can influence hurricane frequency and strength.
The slowdown in hurricanes over the past few years has left scientists wondering whether a high activity era of Atlantic hurricanes, which began in 1995, has ended. "This high-activity era has been associated with an ocean temperature pattern called the warm phase of the Atlantic Multi-Decadal Oscillation or AMO, marked by warmer Atlantic Ocean temperatures and a stronger West African monsoon," NOAA said in a statement. Weakers hurricane seasons from 2013-2015 "have been accompanied by a shift toward the cool AMO phase, marked by cooler Atlantic Ocean temperatures and a weaker West African monsoon," it added.
"If this shift proves to be more than short-lived, it could usher in a low-activity era for Atlantic hurricanes, and this period may already have begun."
The eras of high- and low-activity usually last 25 to 40 years.
"While seasonal forecasts may vary from year to year - some high, some low - it only takes one storm to significantly disrupt your life," said Federal Emergency Management Agency Deputy Administrator Joseph Nimmich.
"Take steps today to be prepared: develop a family communications plan, build an emergency supply kit for your home, and make sure you and your family know your evacuation route."