The Atlantic hurricane season is heading into its peak months, and federal officials now say the Atlantic Ocean could get “above normal” activity this year.
The National Oceanic and Atmospheric Administration updated its seasonal forecast Thursday, predicting a 60% chance of 14 to 21 named storms with winds 39 mph or higher. Six to 11 of them could become hurricanes, including two to five “major” hurricanes that reach Category 3 or higher, with winds of at least 111 mph.
NOAA’s initial forecast, released in May, predicted a 40% chance of a “near-normal” hurricane season. An average season, which begins June 1 and lasts through Nov. 30, typically produces 14 named storms, of which seven become hurricanes, including three major hurricanes, according to the agency.
Matthew Rosencrans, lead hurricane season forecaster with NOAA’s Climate Prediction Center, said the increased likelihood of above-normal hurricane activity is being driven by current ocean and atmospheric conditions — including record-warm sea surface temperatures in the Atlantic Ocean — and the ongoing El Niño event.
"The June-July sea surface temperatures in the main development region of the North Atlantic were the warmest since 1950," Rosencrans said Thursday in a news briefing.
He added that waters in that part of the ocean last month were more than 2 degrees Fahrenheit above normal. Warmer-than-usual ocean temperatures are a key ingredient that fuels the formation of storms.
Global sea surface temperatures have shattered records this year, with parts of the Atlantic Ocean, the Pacific Ocean, the Gulf of Mexico and the Caribbean basin all engulfed in intense and persistent marine heat waves.
But El Niño, a naturally occurring climate pattern characterized by warm ocean surface temperatures in the central and eastern tropical Pacific Ocean, will also play a major role in influencing weather conditions around the world this year, according to NOAA.
El Niño conditions usually suppress storm development by increasing upper-level winds in the Atlantic that can tear hurricanes apart and disrupt major storms as they are forming.
As such, the interplay between warmer-than-usual sea surface temperatures and the ongoing El Niño is the main driver of uncertainty in this season’s forecast, Rosencrans said.
NOAA has said there is a greater than 95% chance that El Niño conditions will linger through the winter.
The agency’s hurricane outlooks are predictions of overall activity during the season but do not make projections about storm landfalls. The updated forecast includes the five named storms and one hurricane that have already formed this season in the Atlantic basin.
Rosencrans said people should take precautions now to prepare for the peak months of hurricane season. Historically, about 90% of all tropical storm activity in the Atlantic occurs from August through October.
“No matter the overall activity, we urge you to prepare now for the upcoming core of the hurricane season,” he said, “as a single storm can have catastrophic impacts.”
