What is El Niño?

Forecasters say phenomenon could mean less-active hurricane season

A recent report by the National Oceanic and Atmospheric Association forecast a less-active Atlantic hurricane season than previously predicted. Experts said a below-normal hurricane season is now 60 percent likely, a sharp increase from the 25 percent predicted in May.

"We are gradually trending toward the El Niño phenomenon, which makes the Atlantic Basin a little less hospitable for tropical development," News 6 meteorologist Samara Cokinos said.

El Niño, a weather phenomenon that is determined by temperatures across the world, might be one of the important factors in the frequency of future hurricane formation. El Niño conditions have not developed in 2018; however, NOAA forecasters said they may still develop at the peak of hurricane season.

What is El Niño?

Translating to "The Little Boy" or "Christ Child" in Spanish, El Niño can be described as abnormally warm differences in the temperatures between a specific area of the Pacific Ocean and the atmosphere.

Experts describes El Niño conditions as the instances when "the atmosphere responds to this warming with increased rising air motion and above-average rainfall in the eastern Pacific." 

The changes in both ocean and atmospheric temperatures begin an El Niño event.

"As the event develops, the warmed waters cause the winds to weaken even further, which can cause the waters to warm even more," according to NOAA forecasters.

El Niño is actually one half of a weather phenomenon that is determined by the air pressure over areas in the east-central Equatorial Pacific. The phenomenon is known as the El Niño-Southern Oscillation. The oscillation, often known as the "ENSO cycle," has two phases: El Niño and La Niña.

According to NOAA, El Niño is sometimes referred to as the "warm phase" of ENSO, while La Niña is the "cold phase." While El Niño entails warmer waters, La Niña is indicated by colder-than-average temperatures. 

Even though El Niño is determined by temperatures in the Pacific, it can have implications in weather patterns all over the world.

What does ENSO mean for Central Florida?

El Niño's development often signals a less-active Atlantic hurricane season, due to the increased wind shear across the tropical Atlantic Ocean, which makes it more difficult for hurricanes to develop. 

"The Pacific Ocean has the opposite reaction," Cokinos said. "That doesn't mean we couldn't get a hurricane, but that’s why you see the Pacific a little more active."

The 2018 hurricane season now has a 70 percent chance of an El Niño event, according to an Aug. 9 report from NOAA. The report said if El Niño develops, it will likely have enough strength to suppress storm development, especially later in the hurricane season, which lasts until Nov. 30.

The opposite is true for La Niña. Its development often signals a more-active hurricane season. The events often, but not always, alternate years, meaning 2018's less-active season could mean more hurricanes in 2019.

According to the NOAA website, El Niño and La Niña usually last between nine and 12 months. Some longer patterns have lasted for years. The events have an average occurrence of every two to seven years, with El Niño appearing more often than La Niña.