The National Oceanic and Atmospheric Administration (NOAA) recently released an update on El Niño-Southern Oscillation (ENSO), a recurring climate pattern involving changes in the temperature of waters in the central and eastern tropical Pacific Ocean.
The water either gets warmer or cooler and affects weather across the world and U.S. A warming of the ocean surface indicates an El Niño could be in charge, while a decrease in water temperatures leads to a La Niña.
El Niño and La Niña are extreme phases of the ENSO cycle, and between them is a neutral phase where, according to NOAA, the Northern Hemisphere has a 50% chance of remaining through the summer.
Colorado State researchers expect above-normal activity this hurricane season. They say there remains uncertainty as to the phase of ENSO for the summer and fall and believe a warmer Atlantic Ocean combined with ENSO neutral or a potential La Niña will be more favorable for hurricanes.
Climatologist David Legates of the Cornwall Alliance says La Niña favors more storms. El Niño is different.
"If you want to build a storm, you want to have the air moving straight up so that the storm can develop," he explains. "If you want to get rid of the hurricane, you want winds at the upper level in a different direction essentially to tear the tower apart so as it starts to build from the moisture below, it literally gets ripped apart."
He does not think the chaotic atmosphere will ever allow forecasts for accurate ENSO phase changes.
"Air of the upper atmosphere doesn't necessarily always do what you think it's going to do, and the hurricanes don't necessarily respond in that same way, either," says Legates. "Correlation says it's more likely to happen when this occurs, but it's never a given."
There are a lot of tenuous jumps, he adds.
Fox Weather notes that the difficulty in accurately predicting ENSO patterns is exemplified by what happened in 2024, when the collapse of an El Niño took longer than initially expected.
Some models showed a possibility of El Niño conditions ending by early spring, but the warm cycle of the ENSO took until early summer to collapse.
NOAA releases its 2025 hurricane outlook in May.
