May 9, 2024 - Energy & Environment

As El Niño fades, hurricane-boosting La Niña looms large

A line chart showing the probability of El Niño or La Niña. Starting in the April to June 2024 period, the probability of El Niño drops to under 25% and the probability of a La Niña starts rising dramatically. By December 2024 to February 2025, there is an 85% chance a La Niña will be in effect.
Data: NOAA/CPC; Chart: Axios Visuals

A once boisterous El Niño in the tropical Pacific is weakening and may give way to ENSO-neutral conditions as early as next month, according to new NOAA data.

Why it matters: A La Niña event is likely to take shape later this summer. The rapid transition would give a significant boost to the Atlantic hurricane season by lowering the wind shear across the Atlantic that can tear such storms apart.

Driving the news: According to the latest update NOAA released this morning, the temperature anomalies in the equatorial tropical Pacific that are El Niño's hallmark are cooling. Soon, they will fall below the threshold for an El Niño declaration.

  • Strong El Niños such as this one have a tendency to be followed by La Niña events, which are characterized by cooler-than-average waters in the eastern tropical Pacific.
  • There are signs that La Niña is already developing, with cooler-than-average waters located beneath the surface, gradually rising higher in the water column.
  • However, a declaration is not expected until sometime this summer or early fall, according to meteorologist Michelle L'Heureux, who leads NOAA's ENSO forecasting team.

Zoom in: The latest odds of La Niña show a sharp increase in probabilities from just 11% in May through July, to 69% in July through September.

What they're saying: "At this point we're still on target for a transition to La Niña during the summer or summer-ish season," L'Heureux told Axios via email.

  • Still, she said, the transition will take some time, noting the presence of a lot of unusually warm water in the equatorial Pacific Ocean.
  • "Even the cooler pools of below-average SSTs recently reaching the surface have a lot of warmth surrounding them. This, among other reasons, is the primary reason we felt we couldn't call it over *quite yet.*
  • "But a transition to ENSO-neutral is fairly imminent," she said.
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