A Super El Niño is coming. Here’s how a hotter ocean could change the weather near you

By Andrew Freedman, CNN

(CNN) — Get ready to hear a lot more about El Niño during the next several months — and maybe even longer — as the infamous climate cycle returns again, developing and intensifying in the Pacific Ocean near the equator. If it forms as expected, this El Niño will redraw global weather maps, sparking flooding for some and drought and wildfires for others — all while simultaneously speeding up the pace of global warming.

There are increasing indications that an El Niño is not only imminent — setting in by late summer or early fall — but that it could be a significant one, too.

In fact, this might even qualify as a “Super El Niño,” which would significantly increase impacts felt around the world. Such extremely intense El Niños are rare.

To declare an El Niño, in general, ocean temperatures in a particular region of the tropical Pacific must clear 0.5 degrees Celsius above the long-term average. A Super El Niño, in contrast, happens when temperatures are more than 2 degrees C above the average. Some typically reliable computer models, like the European modeling suite, are projecting just such an outcome for this go-around.

The baddest kids in town

El Niño and La Niña, names that translate to “the Boy” and “the Girl”, are recurring climate cycles in the tropical Pacific Ocean that happen every few years and can have profound effects on global weather patterns. In the case of El Niño, the cycle can bring both flooding and drought to different parts of Africa, help pummel the U.S. West Coast with winter storms and lead to more heat extremes globally.

El Niño is characterized by unusually warm waters along the equatorial tropical Pacific Ocean, and a related series of shifts in winds and precipitation patterns in the atmosphere. It is a so-called coupled phenomenon, meaning that to get an El Niño, both the ocean and the atmosphere must be responding to one another in characteristic ways.

The atmosphere tends to react to the warmer waters by shifting areas of heavy precipitation closer to that hot region of the ocean. The trade winds that typically blow from east to west near the equator can slacken and then reverse direction as well. Those shifts are significant enough to affect weather around the world, like a series of dominoes toppling over.

Right now, huge volumes of unusually warm water are spreading under the ocean surface from the Western to the Eastern tropical Pacific, where that water slowly rises to the surface in a clear precursor to El Niño. Periodic areas of wind blowing from the west to the east have helped transport this water, in what are appropriately known as westerly wind bursts.

While El Niño and La Niña, El Niño’s cooler sibling, are fascinating from a meteorological perspective, we care about them because of the ways in which they can affect extreme weather events around the world. In fact, they can cause billions of dollars in damages, and a stronger El Niño would likely make the usual impacts more severe.

Spotting an El Niño in formation and predicting its evolution “gives us an early heads up on changing risks for many weather-related phenomena, including floods, droughts, heatwaves, hurricanes and severe thunderstorms,” said Nat Johnson, a meteorologist at the National Oceanic and Atmospheric Administration’s Geophysical Fluid Dynamics Laboratory. “These weather and climate impacts modify crop yields, disease spread, coral bleaching, fisheries and many other parts of the earth system that affect our daily lives.”

There’s still a lot of uncertainty around the upcoming El Niño, including a range of forecast outcomes, especially when it comes to intensity, Johnson said. To cloud matters a bit further; computer model projections made during the spring tend to have lower accuracy than projections made at other times of the year, a phenomenon known as the spring prediction barrier.

Hot and hotter

In the U.S., El Niño tends to have its peak effects during the winter months, when it can send a fusillade of storms into parts of California and along the southern tier of the U.S., bringing the risk of flooding.

It can also speed up winds in the upper atmosphere across the tropical Atlantic Ocean during the fall. This causes wind shear to increase, and this can tear apart nascent tropical storms and hurricanes — putting a damper on the Atlantic hurricane season.

In addition, strong El Niño’s have also been linked to heat waves in the U.S. and other parts of the world.

Globally, El Niño is known to tilt the odds in favor of drought and heat waves in Australia, where it can also raise wildfire risks. Other areas prone to drought during El Niño include northern sections of South America (including parts of the Amazon rainforest), central and southern Africa and India. El Niño can also cause too much rain to fall, with favored areas for flooding outside of the U.S. including southeastern South America, the Horn of Africa, Iran, Afghanistan and other parts of south-central Asia.

When it comes to the climate, El Niño tends to release enormous amounts of heat stored in the oceans back into the atmosphere, boosting global average surface temperatures. If a strong El Niño does form and continues through the winter, then it is almost assured that either 2026, 2027 or both years will set new records for the warmest year since instrument data began in the 19th century.

The globe is already warming at an accelerating rate, and an intense El Niño would speed that up even faster, at least for a few years. If climate change is like ascending an escalator, with some years warmer than others, an El Niño year is equivalent to jumping up and down while riding on that escalator — reaching record new heights, albeit briefly.

The last El Niño, which was not a Super El Niño, resulted in 2024 being the current holder of the warmest-year title. The last Super El Niño occurred in 2015-2016, with others in 1997-98, and 1982-83. Super El Niños are not a technical designation from NOAA but instead are an informal definition used by some forecasters and the media to refer to a very strong El Niño

Meteorologists will be closely watching as the Pacific waters heat up to see just how strong an El Niño we get. If the European model is proven correct, it could even be the strongest El Niño on record.

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