NOAA Declares El Niño Underway as NASA Satellites Show Strengthening in Equatorial Pacific

NOAA has officially declared El Niño underway, and new NASA satellite observations show the climate pattern strengthening across the equatorial Pacific. In an ENSO Diagnostic Discussion issued June 11, NOAA’s Climate Prediction Center set its alert status to “El Niño Advisory” and said, “El Niño conditions are present and expected to strengthen into the Northern Hemisphere winter 2026–27.” The agency also said there is a 63% chance the event becomes “very strong” during the November-through-January period — a level that, if reached, would place it among the biggest El Niño events in records dating to 1950.

That matters because El Niño, the warm phase of the El Niño-Southern Oscillation, is one of the world’s most important seasonal climate patterns. When it strengthens, it can shift rainfall, temperatures and storm tracks far beyond the tropical Pacific, changing the odds of wet or dry conditions in many regions.

The latest official benchmark shows the event has already crossed into El Niño territory. In its June 11 discussion, the Climate Prediction Center said the weekly Niño-3.4 index — a key measure of sea-surface temperatures in the central equatorial Pacific — was at plus-0.7 degrees Celsius.

NASA’s Earth Observatory added a fresh visual confirmation on Thursday in a report titled “El Niño Is Underway,” based on Sentinel-6 Michael Freilich satellite altimetry from June 8. The data showed higher-than-normal sea-surface height across the central and eastern equatorial Pacific, a pattern consistent with a strengthening El Niño.

That signal is important because warm water expands. When satellite instruments detect elevated sea level in the tropical Pacific, they are often capturing not just warmer surface water but also a buildup of heat below the surface. That subsurface reservoir can help feed and sustain El Niño as the event develops.

NASA’s Jet Propulsion Laboratory had already reported another warning sign on May 27: a warm Kelvin wave, an eastward-moving pulse of warm water, had crossed the Pacific. By mid-May, JPL said, sea levels off Peru were more than 5.9 inches, or about 15 centimeters, above long-term averages. Severine Fournier, a JPL ocean physicist quoted by NASA Earth Observatory, said: “For now, it looks like it’s going to be a big one—more so than I would have said last week—but we still need more observations to know what’s going to happen.”

Forecasters are looking not only at the ocean but also at the atmosphere. The Climate Prediction Center said wind and convection patterns were now behaving in ways consistent with El Niño, showing that the ocean and atmosphere had become coupled — an important threshold for formal classification.

Other forecasters are seeing the same broad picture. The World Meteorological Organization said June 2 there was an 80% likelihood of El Niño during June through August 2026, with probabilities near or above 90% that it would continue until at least November.

A stronger El Niño can tilt seasonal weather odds around the globe. Typical effects include wetter winter conditions in parts of the U.S. Southwest, drier conditions in Australia and Indonesia, and reduced Atlantic hurricane activity. But those are tendencies, not guarantees, and the exact pattern depends on how strong the event becomes and how it evolves.

The strongest modern El Niño episodes often cited are 1997-98 and 2015-16. NOAA is not saying the 2026 event will match those events. What forecasters are saying is that confidence is high El Niño is here and intensifying, and that the odds of a very strong event are unusually elevated. How high it ultimately peaks will depend on what the ocean and atmosphere do over the next several months.