Forecasters have released updated guidance on El Niño and its potential impact on summer weather patterns.
In a Thursday update, the National Weather Service (NWS) Climate Prediction Center (CPC) said that a shift from La Niña to ENSO‑neutral is expected within the next month, with ENSO‑neutral conditions favored through May-July 2026 (55 percent chance). By June-August 2026, El Niño is expected to develop (62 percent chance) and persist through at least the end of 2026.
The agency said its La Niña advisory remains in place, and an El Niño watch has been issued.
An advisory is issued when La Niña or El Niño conditions "are observed and expected to continue," while a watch signals that "conditions are favorable for the development of El Niño or La Niña conditions within the next six months."
El Niño and La Niña represent the warm and cool phases of a recurring climate pattern in the tropical Pacific called the El Niño-Southern Oscillation, or "ENSO." This system shifts irregularly every two to seven years, driving predictable swings in ocean temperatures and altering typical wind and rainfall patterns across the tropics.
During La Niña, trade winds intensify beyond their usual strength, pushing larger amounts of warm surface water toward Asia. This enhances upwelling along the western coasts of the Americas, drawing colder water up from below the surface.
These cooler Pacific waters force the jet stream farther north, often leading to drought in the southern U.S. while increasing the risk of heavy rain and flooding across the Pacific Northwest and Canada. In La Niña years, winter temperatures are typically warmer than average in the South and cooler than normal in the North. La Niña can also help fuel a more active and intense hurricane season, according to NOAA.
By contrast, during El Niño, trade winds weaken, allowing warm ocean water to shift eastward toward the Americas. This warming nudges the Pacific jet stream south of its normal position. As a result, the northern U.S. and Canada often see warmer, drier conditions, while the Gulf Coast and Southeast are more likely to experience wetter‑than‑normal weather and a heightened flood risk.
In an email to Newsweek on Friday, AccuWeather forecasters said El Niño forms when sea surface temperatures in the eastern tropical Pacific near the equator rise at least 0.5 degrees Celsius (0.9 degrees Fahrenheit) above the long-term average for three consecutive months. AccuWeather added that this year's event could strengthen into a so‑called "super El Niño," which occurs when ocean temperatures climb to 2 degrees C or more above normal across the ENSO region.
"We feel El Niño will form this summer, early to mid is the expectation. Intensity is uncertain, but there is potential for a moderate to possibly strong El Niño this fall into winter. Water temperatures expected over the equatorial Pacific and Indian Ocean are supporting an El Niño with impacts on the tropical season and southern U.S. moisture this summer and fall," said AccuWeather lead long-range expert Paul Pastelok.
"El Niño tends to increase the mid- to upper-level wind shear (stronger winds with height and change in direction) on a more frequent basis across portions of the Atlantic Basin. This can lead to less storm development: a roadblock to a hyperactive hurricane season this year."