El Niño could be here soon, bringing wild weather and a hotter climate

Young men inspect a car destroyed by flood waters in an area heavily affected by torrential rains, near Mai Mahiu, Kenya on April 29, 2024. An El Niño event that year made the storms worse than they would normally have been. (Luis Tato/AFP/Getty Images/File via CNN Newsource)

There are increasing indications El Niño is likely to form and strengthen into potentially a significant event during the next several months, throwing weather patterns worldwide out of whack. El Niño could affect the Atlantic hurricane season (if the timing is right) and heat the planet even further, making another record warm year much more likely than it otherwise would be either this year or next.

The U.S. National Oceanic and Atmospheric Administration issued an El Niño watch on Thursday morning, meaning conditions are favourable for it to develop during the next six months.

NOAA meteorologists predict El Niño will develop some time between June and August and last through at least the end of the year, and there is a 1-in-3 chance it will become “strong” by the winter months — which would have a significant impact on winter weather in the US.

El Niño and La Niña are periodic climate cycles in the tropical Pacific Ocean that occur every few years and can have profound effects on global weather patterns. They can bring flooding to parts of Africa and drought to other areas, help pummel the West Coast with winter storms while leading to more heat extremes globally in the case of El Niño.

El Niño is characterized by unusually warm waters along the equatorial tropical Pacific Ocean, and a series of shifts in winds and precipitation patterns in the atmosphere. Those shifts are significant enough to affect weather around the world. Right now, unusually warm water is spreading under the ocean surface from the Western to the Eastern tropical Pacific, in what may be a precursor to such an event.

While there is still considerable uncertainty in the forecast, most projections from El Niño monitoring groups in the US and Australia, among others, show a current weak La Niña waning in the next few months. La Niña is El Niño’s cooler water sibling that can also lead to global weather disturbances. For now, experts are expecting the emergence of so-called “ENSO Neutral” conditions, meaning that neither a La Niña or an El Niño is present, for much of the latter half of spring and into the summer.

Then, depending on myriad factors ranging from the direction and strength of trade winds to the sloshing of warmer than average ocean waters from the Western to the Eastern tropical Pacific Ocean, an El Niño may emerge sometime in the late summer to fall time frame.

Forecasters said there is a 1-in-3 chance that this El Niño will become a strong event. The presence of an El Niño would make it far more likely that 2026 or 2027 would set the next milestone for the warmest-year on record.

Outlooks from NOAA, Australia’s Bureau of Meteorology, and other groups all show the same general scenario, with varying degrees of confidence and slight differences in timing.

Right now, while the ocean is beginning to look more El Niño-like and projected to become even more so, the atmospheric circulation still reflects the influence of a weak La Niña. This means that the effects of an El Niño, should one develop, are still several months away.

In order to be more confident in predicting an El Niño, trade winds blowing from east-to-west across the equator would need to slacken, allowing more warm water from the western Pacific to push east and emerge at the surface. So far, this shift in the trade winds has not occurred consistently, but computer models project that this will change during the next few months.

In fact, some computer models, including the well-regarded European ensemble, are quite aggressive in developing an El Niño and progressing it into an intense “Super El Niño” event by late Fall. If this were to occur, the Atlantic hurricane season could be sleepier than usual, since El Niño’s tend to be accompanied by stronger wind shear over the tropical Atlantic Ocean.

Wind shear, which occurs when winds blow at different speeds and/or directions with height, acts as an impediment to fledgling tropical storms and hurricanes.

El Niño years also tend to boost global average surface temperatures, thereby acting in concert with human-caused global warming to set heat records. A strong El Niño, sometimes referred to as a “Super El Niño,” would be all but certain to vault global temperatures into record territory — speeding up warming further and potentially leading to more coral bleaching and other damaging effects.

Forecasters caution that El Niño predictions tend to be less accurate at this time of year, in what is known as the spring prediction barrier. One forecaster likened the barrier to forecasting in a fog, waiting for it to clear up before being more confident of what will happen next.

The barrier refers to a period when computer model projections for seasonal climate forecasting tend to be less reliable than at other times of the year. The greater uncertainty means that even though observational signs are starting to point to a developing El Niño, and computer models show an El Niño is more likely than not to emerge during the coming months, confidence in this scenario is not very high.

Typically, El Niño forecasts tend to become more reliable in June as summer approaches.

By Andrew Freedman