El Niño has formed. Forecasters expect a global weather powerhouse.

A long-awaited and dramatic global climate change is coming, federal forecasters said on June 11, as they confirmed the onset of El Niño conditions.

The announcement also adds to growing evidence that El Niño will be unusually strong, potentially exacerbating droughts, intense rainfall events and heat waves. Previous El Niños have led to some of the warmest years on record, such as the record-breaking average temperature worldwide in 2024.

El Niño is part of a larger climate cycle driven by the temperature of the water in parts of the Pacific Ocean. The natural climate pattern affects weather patterns across the planet, creating mixed conditions around the world.

A new forecast from the National Oceanic and Atmospheric Administration’s Climate Prediction Center predicts a “very strong” El Niño. It could grow large enough to rival the strongest El Niño events in the historical record dating back to 1950, the climate center’s Michelle L’Heureux said in an email to USA TODAY.

By the way, not all of El Niño’s effects are malevolent. This pattern is also expected to reduce hurricane activity in the Atlantic and bring a milder winter (and lower heating bills) to millions of Americans.

Why is the transition to El Niño important?

World leaders have expressed concern about the possibility of droughts, heavy rainfall events and heat waves.

“The world should treat this as an urgent climate warning. El Niño conditions will fuel the fires of a warming world,” United Nations Secretary-General António Guterres said in a video statement in early June.

A strong event could create ripple effects in the coming months, and the new forecast says the likelihood of a strong event is increasing.

“In NOAA’s latest update, we have a 63% chance of being ‘very strong’ next winter,” L’Heureux said. he said.

“We have 7 very strong events in our record, so this event has a good chance of reaching that level,” he said. “There is still some uncertainty as there is a 1 in 3 chance that this will not be a very strong El Niño.”

While there is no evidence that climate change is increasing the frequency or intensity of El Niño events, the World Meteorological Organization has noted that it could increase the effects. Given that water temperatures in the tropical Pacific are already 10 degrees Fahrenheit above average, concerns are growing at the United Nations that this El Niño could feed on this extra heat and “devastate vulnerable and unprepared communities around the world.”

Warm water is key to El Niño forecast

When federal forecasters confirmed El Niño conditions on June 11, they used data from satellites that showed persistent changes in winds and water temperatures in the tropical Pacific Ocean.

During the first week of June, temperatures briefly rose rapidly in the El Niño region, reaching record levels for this time of year. Those rates dropped slightly but remained above previous records on June 9, according to a visualization from the Climate Reanalyzer at the University of Maine Climate Change Institute.

El Niño is part of a climate cycle known to scientists as the “El Niño – Southern Oscillation” or ENSO. But it was first recognized by fishermen off the coast of South America in the 1600s, when unusually warm water appeared in the Pacific Ocean around Christmas. His name means Little Child or Jesus Child in Spanish.

When El Niño conditions are not present, the cycle may be in neutral or La Niña phases.

“Although this year’s event started a little later than the major El Niños of 2015 and 1997, it’s starting to catch up,” Josh Willis, a sea level researcher at NASA’s Jet Propulsion Laboratory, said in late May. “We’ll see how big it gets.”

How will El Niño affect US weather forecasts?

Forecasters say it’s too early to know the details, and it will always be difficult to determine El Niño’s exact impact on the weather. But the climate model has the distinctive features forecasters expected.

• Be careful of hot weather. According to AccuWeather, there is the potential for a drier, hotter summer in some areas across the Northwest, Northern Plains and Upper Midwest, prolonging the ongoing drought and increasing the risk of wildfires. In general, El Niño increases the likelihood of above-average temperatures in the northern and western parts of the United States.

• Rain (finally) in the Southeast. El Niños could lead to wet conditions along the Gulf Coast and Southeast, easing ongoing drought in those regions, according to AccuWeather.

• California could face more rain and snow. California tends to have a much wetter year with El Niño, said Abby Frazier, a professor of geography in the school of climate, environment and society at Clark University. Frazier said that’s never a guarantee because every El Niño is different. “But most of the time we can expect conditions to be more favorable for things like atmospheric rivers that bring a lot of rain to Southern California.” Heavier snowfall is also possible in the California mountains, according to AccuWeather.

• Wildfire concern in Hawaii. Hawaii may also see increased precipitation during the summer months, followed by dry drought conditions during the fall and winter, Frazier said. The increased risk of wildfires in Hawaii is particularly concerning, he said. “If we get more precipitation in the summer, all the grass and things that fuel fires grow quickly, then dry out in the winter, so we often see fire season start earlier.”

• Atlantic hurricane season may be less active. Colorado State University hurricane researcher Phil Klotzbach said we can already see signs that El Niño is causing an increase in upper-level westerly winds across the tropical Atlantic. These winds act to prevent tropical storms from forming.

• Pacific Hurricane season expected to be busy. El Niño tends to significantly increase activity in the eastern North Pacific, particularly in the central and western parts of the basin, Klotzbach said. Warmer waters, increased low-level rotation, and reduced vertical wind shear are contributing to this increase.

All is not necessarily doom and gloom, said the climate centre’s L’Heureux. “Remember that El Niño-related impacts are not necessarily concerning.”

“While it increases the chances of more extreme weather in various parts of the world, there are also positives, such as potentially lower heating bills for the northern part of the United States during the winter months. A possible reduction in tropical cyclone activity in the Atlantic basin is also potentially beneficial.”

Frazier said that, unlike other weather events, El Nino gives advance notice.

“This is one of the few events that we can actually plan six months in advance,” Frazier said. “There aren’t many other things in our weather forecast world that give us this much lead time.”

Dinah Voyles Pulver and Doyle Rice are national correspondents for USA TODAY and write about hurricanes, severe weather and climate change. You can reach him at dpulver@usatoday.com or @dinahvp on Bluesky or X, and Doyle at drice@usatoday.com.

This article first appeared on USA TODAY: El Nino forms; NOAA predicts one of the largest in history