Sea surface temperatures across portions of the equatorial Pacific have warmed enough for forecasters at the National Oceanic and Atmospheric Administration to declare that an El Niño event is underway.
El Niño is one of three phases of the El Niño-Southern Oscillation or what is commonly referred to as the ENSO.
The status of ENSO varies between El Niño, La Niña and a neutral phase, depending on sea surface temperatures across the central and eastern Pacific Ocean.
An El Niño is considered to be underway when sea surface temperatures reach at least 0.5 degrees Celsius above normal over an extended period.
The current event had been widely anticipated by computer forecast models, with some guidance indicating a significant El Niño could develop later this year.
A super El Niño is considered to be underway when water temperatures across the Pacific reach at least 2 °C above average.
The strength and timing of an El Niño can result in widespread impacts across North America, influencing everything from hurricane activity to winter storms and severe weather outbreaks.
For Florida, some of the earliest impacts may begin to become noticeable later this summer.
When an El Niño develops during the warm season, drier-than-normal conditions are often favored from August into October.
One contributing factor to the reduced precipitation is decreased tropical activity across the Atlantic basin.
El Niño tends to increase vertical wind shear, which disrupts developing tropical cyclones and limits opportunities for strengthening.
Hurricane forecasters at Colorado State University and NOAA have already taken the status of ENSO into account for their annual Atlantic basin tropical season outlooks.
Experts at CSU are expecting a quieter-than-normal Atlantic hurricane season, with 11 named storms, five hurricanes and two major hurricanes.
“Sea surface temperatures in the western tropical Atlantic are near average but are cooler than normal in the eastern and central tropical Atlantic. We anticipate El Niño being the dominant factor for the upcoming hurricane season, driving increased levels of tropical Atlantic vertical wind shear. We are forecasting a below-average probability for major hurricane landfalls along the continental United States coastline and in the Caribbean,” CSU forecasters stated in their most recent seasonal outlook.
While El Niño’s influence on tropical activity often receives wide attention during the summer and fall, the climate pattern’s influences become even more noticeable later in the year.
Across the Southeast, El Niño historically favors a stronger and more active subtropical jet stream during the winter.
This pattern often results in increased cloud cover, cooler temperatures and more frequent precipitation.
From December through March, precipitation totals across parts of the region can average 30% to 50% above normal during an active El Niño event.
The increased precipitation often leads to an uptick in severe weather reports across the Sunshine State when compared to La Niña years.
A typical El Niño lasts 9 to 12 months, meaning the current episode will likely persist well into 2027 and influence weather patterns around the globe.
