El Niño Pattern Boosts Eastern Pacific Hurricane Outlook as Season Starts

The Pacific Ocean's waters are warming as an El Niño climate pattern takes hold, just as the Eastern Pacific hurricane season starts on Friday, May 15.

Warm ocean waters fuel tropical cyclone development, and El Niño creates ideal conditions for a busy season in the Eastern Pacific. The pattern reduces vertical wind shear, or changes in wind direction at higher altitudes. That lets tropical systems organize over warmer waters without getting torn apart.

El Niño pushes conditions the other way in the Atlantic basin. Cooler waters and higher wind shear there hinder tropical storm formation. Atlantic hurricanes will not disappear, but their numbers could fall below average.

The last El Niño hit in 2023. A La Niña pattern followed, matching the above-average Atlantic seasons in recent years.

That 2023 Eastern Pacific season saw 20 tropical systems, with 17 gaining names. Hurricane Hilary crossed Baja California as a hurricane, hit land as a tropical storm, and reached the southwestern U.S. It affected California, Arizona and Nevada, causing three deaths and more than $900 million in damage across the U.S. and Mexico.

Last year's Eastern Pacific season, under La Niña, produced 18 tropical systems. Major Hurricane Kiko aimed at the Hawaiian Islands, weakened in cooler waters and broke up just north of them.

This season's first names on the six-year rotating list are Amanda, Boris, Cristina and Douglas.

The National Hurricane Center will track the Eastern Pacific through season's end with Tropical Weather Outlooks issued several times a day.