The National Oceanic and Atmospheric Administration lowered the outlook on hurricane activity in the Atlantic last week, but not without adding the caveat that dangerous storms can occur during any season.
The agency is now predicting a near- to below-normal hurricane season, including a 50 percent probability of a near-normal season and a 40 percent probability of a below-normal season, according to a NOAA statement. The downgrade is attributed to increasing El Niño conditions, which can take the wind out of a growing hurricane’s sails.
“El Niño continues to develop and is already affecting upper-level atmospheric pressure and winds across the global tropics,” NOAA Lead Hurricane Forecaster Gerry Bell stated. “El Niño produces stronger upper-level westerly winds over the Caribbean Sea and tropical Atlantic Ocean, which help to reduce hurricane activity by blowing away the tops of growing thunderstorm clouds that would normally lead to tropical storms.”
Although the Atlantic hurricane forecast has now dipped to a 70 percent probability of seven to eleven named storms—down from nine to fourteen predicted in May—NOAA cautions coastal residents to stay vigilant and prepared. Hurricanes such as Betsy, Camille, and Lili all wreaked intense damage, even though they formed during El Niño conditions, according to NOAA.
On the heels of the NOAA announcement, the journal Nature this week released a study that indicates the intensity of recent years’ hurricanes might be a “naturally occurring millennial peak,” tied to the El Niño-La Niña cycle.
The study, lead by Pennsylvania State University climate scientist Michael Mann, examined 1,500 years of storm sediment from core samples drawn from Atlantic lagoons. The results add “validity to the theory that two factors fuel higher hurricane activity, namely the La Niña effect and high surface temperatures over the ocean,” according to a National Science Foundation statement.
“If climate change continues to warm ocean waters, it could lead to more active hurricane seasons,” Mann told the NSF.
Although the new report was covered widely by popular media outlets, it’s not without detractors, who are concerned about the study’s methodology and say it refutes Mann’s earlier work. For more on the opposing side, see Roger Pielke’s Changing Perilious Assumptions to Fit the Analysis or More Check Kiting at Nature by Steve McIntyre.
Jolie Breeden is the lead editor and science communicator for Natural Hazards Center publications. She writes and edits for Research Counts; the Quick Response, Mitigation Matters, Public Health, and Weather Ready Research Award report series; as well as for special projects and publications. Breeden graduated summa cum laude from the University of Colorado Boulder with a bachelor’s degree in journalism.