A potentially historic El Niño is strengthening in the Pacific, raising the prospect of shifting weather patterns across parts of the U.S., including changes in rain, storm risk and tropical activity affecting Florida, Texas and California. Florida meteorologist Matt Devitt said in a Monday post on X that forecasts suggest this El Niño could surpass anything seen since at least 1850, potentially setting a 176-year benchmark. While El Niño begins in the tropical Pacific, its effects can reshape weather patterns across the U.S.
El Niño is the warm phase of the El Niño-Southern Oscillation, or ENSO, a natural climate pattern in the tropical Pacific that shifts irregularly every two to seven years. La Niña is the cool phase of the same pattern. During El Niño, trade winds that normally push warm surface water westward across the Pacific weaken, allowing warmer water to move back east toward the Americas.
NOAA said ENSO changes can shift normal wind and rainfall patterns in the tropics and affect weather in other parts of the world. In the U.S., El Niño can shift the Pacific jet stream south, and typically brings wetter-than-usual conditions and increased flooding to the southern U.S., including the Gulf Coast and Southeast, while the northern U.S. and Canada tend to be warmer and drier than usual, according to the agency. The climate phenomenon can also impact how hurricane seasons play out.
The agency’s outlook also said there is a 69 percent chance that the event reaches “historic” strength during the October-December season, exceeding previous El Niño events in records dating back to 1950. For Florida, AccuWeather senior meteorologist Adam Douty told Newsweek El Niño often increases wind shear across the Atlantic basin, which can make it harder for tropical systems to form and strengthen during the summer and fall. That can reduce the risk of tropical impacts, but it may also allow drought conditions in the state to continue.
The pattern can shift by winter. Douty said a stronger subtropical, or southern, jet stream “typically brings a wetter pattern to Florida” and can also raise the risk of severe weather. He added that “some of Florida’s largest tornado outbreaks have occurred during El Niño years.” Texas can also see a lower tropical risk during El Niño, Douty said, because increased wind shear can make it more difficult for tropical features to develop and intensify.
As in Florida, a change may come in winter, when a stronger subtropical jet can bring more frequent storms and precipitation to the state, according to the meteorologist. In California, Douty said El Niño can raise the chances of tropical moisture or tropical systems influencing the state by increasing tropical activity in the eastern Pacific. Later in the fall and winter, he said, “a more southern storm track could favor increased precipitation across central and Southern California.” That would broadly fit the pattern often seen during El Niño, although Douty cautioned that the exact location and amount of rain would depend on where storms track and on other factors, including North Pacific water temperatures.
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