NASA satellites track what could be the strongest El Niño since 1950

A warm-water event unfolding across the equatorial Pacific is showing up clearly from orbit, NASA said in an Oct. 15 update, as federal forecasters warn it may become the strongest El Niño on record since 1950.

NOAA's Climate Prediction Center, in its Oct. 8 monthly discussion, kept an El Niño Advisory in place and called for a strong-to-very strong event likely lasting through January-March 2027.

The numbers

| Measure | Value | Source | |---|---|---| | Latest monthly Niño-3.4 anomaly | +2.1°C | NOAA CPC | | Chance of historic-strength event, Oct.-Dec. | 83% | NOAA CPC | | Eastern Pacific surface temperatures | about 3°F above average | NASA | | Sea level rise in some Pacific areas | up to 1 to 1.3 feet | NASA |

What the satellites see

NASA traced the first signs to January, when a Kelvin wave, a slow pulse of water thousands of miles long, appeared near Micronesia. By early April such waves had reached the eastern Pacific.

The Sentinel-6 Michael Freilich satellite, which measures ocean height about every 10 days, recorded higher water in the east and levels 6 to 8 inches below normal near Indonesia and northern Australia. JPL scientist Josh Willis called Kelvin waves "the heartbeat of El Niño."

NASA's PACE satellite, launched in 2024 and observing its first El Niño, found equatorial waters turning bluer as phytoplankton decline. Weaker trade winds reduce the upwelling of nutrients those organisms need, the agency said.

NOAA did not spell out U.S. winter impacts in the discussion. It said an event this large makes typical El Niño effects more likely, but not guaranteed, and pointed readers to its seasonal outlooks.