'Uncharted territory': El Niño to flip to La Niña in what could be the hottest year on record

El Niño is likely to give way soon, ushering in a quick switch to its opposite atmospheric and ocean pattern, La Niña. 

For the U.S., this climatological flip-flop will likely mean a greater risk of major hurricanes in the Atlantic as well as areas of drier-than-usual weather in the southern portions of the country. Globally, La Niña usually leads to declining temperatures, but the lag in when the effects take place means that 2024 will likely still be a top-five year for temperature in climate History, said Tom Di Liberto, a climate scientist at the National Oceanic and Atmospheric Administration (NOAA). 

"All signs suggest that 2024 is going to be another warm year," Di Liberto told Live Science. 

El Niño and La Niña describe opposing patterns in the trade winds that encircle the equator, blowing west from South America toward Asia. In a neutral year, when neither pattern is in play, these trade winds push warm water westward, which drives cool ocean water up from the depths to replace it. 

When El Niño is in play, the trade winds weaken, so the eastern Pacific, along the west coast of North and South America, stays warmer. The effect, according to NOAA, is that the jet stream moves southward, drying Canada and the northern U.S. but bringing moisture to the southern portions of the U.S. 

Related: Why don't hurricanes form at the equator?

In a La Niña year, the trade winds strengthen, pushing warm water toward Asia and increasing the upwelling of cold water off the Pacific coast of the Americas. The jet stream moves northward, drying the Southwest and Southeast and bringing wetter weather to the Pacific Northwest and the Great Lakes.