ORLANDO, Fla. – While La Niña is currently holding its own, the expectation is that an El Niño will develop by the peak of hurricane season.
A transition to ENSO Neutral, neither El Niño or La Niña is likely by the start of hurricane season.
Heading into an El Niño is big deal because, in a typical El Niño pattern, upper-level winds increase over the Caribbean and parts of the tropical Atlantic, creating more wind shear. Wind shear is one of the most detrimental tings to hurricane development and intensification.
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It’s important to note that devastating hurricanes can still occur during an El Niño. What El Niño does is tilt the background setup to make a weather pattern that is less favorable for storms, especially in the Caribbean.
So how do we get there? This all ties back to ENSO — the El Niño–Southern Oscillation — which is a natural cycle in the equatorial Pacific. And despite how far away that ocean water is, it can ripple into weather patterns across the U.S. for months.
If you’ve heard people describe El Niño and La Niña as “just ocean temperatures,” that’s only part of the story. ENSO is really an ocean-and-atmosphere partnership. Yes, we track sea-surface temperature anomalies in the central and eastern equatorial Pacific, but the atmosphere responds, too — and that upper-air response is what helps rearrange the jet stream and, downstream, our storm tracks.
To classify whether we’re in El Niño or La Niña, meteorologists commonly use a threshold of about 0.5 degrees Celsius above or below average in the key monitoring region. Around +0.5 degrees Celsius starts to qualify as El Niño; around –0.5 degrees Celsius starts to qualify as La Niña. What’s interesting in the forecast guidance is how many model members rise well above that warm threshold later in the year. Some solutions don’t just hint at a weak El Niño — they suggest a stronger one, with certain guidance (including some European model camps) pushing anomalies above +1.0 degrees Celsius and even closer to +1.5 degrees Celsius.
As of the February update, we’re still in La Niña. A lot of folks expected we’d be trending toward ENSO-neutral by now, but the latest numbers show the cool-phase signal hanging on — and in some ways even looking a bit stronger than the prior update. That matters because timing is everything. If La Niña lingers and then fades quickly, it can make the spring-to-summer forecast feel like a moving target.
Regardless, how ENSO evolves over the coming months will have big ramifications for not only hurricane season, but moisture in the fall and winter months.
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