NASA and European partners have tracked a large pulse of warm water moving across the Pacific Ocean toward South America. The observation, captured by the Sentinel-6 Michael Freilich satellite, raises the possibility that El Niño conditions could develop later this year.
Data from the satellite showed sea levels near Peru more than 5.9 inches above average by mid-May. This rise stems from Kelvin waves that carry warm water eastward after wind patterns shift in the western Pacific.
Josh Willis, a sea level researcher at NASA's Jet Propulsion Laboratory, noted the timing. "While this year's event started a bit later than the big El Niños of 2015 and 1997, it's beginning to catch up," he said. "We'll see how big it gets."
Nadya Vinogradova Shiffer, lead program scientist at NASA Headquarters, said the satellite helps track these waves to improve forecasts of weather extremes. El Niño events typically peak between November and January, with effects that can include heavy rain in some areas and drought in others.
A second satellite, Sentinel-6B, launched in November 2025 and is expected to take over monitoring duties by the end of 2026.
