CPC's November Discussion: Niño 3.4 at +2.5 °C and 79% Odds Into Early 2027

NOAA's Climate Prediction Center held its ENSO Alert System Status at El Niño Advisory in the monthly diagnostic discussion issued on 12 November 2026, reporting that the event has continued to strengthen and that a strong-to-very strong El Niño is likely to persist through January–March 2027 — a probability the agency gives as greater than 79%.

The centre described sea surface temperature anomalies in the eastern equatorial Pacific exceeding 4.0 °C and spreading farther west than a month earlier. All three of the headline monthly Niño indices rose: CPC logged +2.5 °C in Niño-3.4, +3.6 °C in Niño-3 and +4.4 °C in Niño-1+2.

What the ocean and atmosphere showed

Below the surface, CPC said the equatorial subsurface temperature index — averaged between 180° and 100°W — remained significantly above average, a signal it linked to a deeper-than-average thermocline and to anomalies exceeding +10.0 °C at depth in the eastern Pacific. A deep reservoir of warm water of that kind is the ocean memory that sustains a surface warm anomaly rather than letting it dissipate.

The atmosphere, by CPC's account, is behaving consistently with the ocean. Low-level westerly and upper-level easterly wind anomalies stretched from the western to the east-central equatorial Pacific. Convection and rainfall stayed enhanced from the central to the eastern Pacific, while suppressed conditions persisted over Indonesia — the characteristic eastward shift of tropical rainfall associated with El Niño. Both the traditional and equatorial Southern Oscillation indices were consistently negative. Taken together, CPC concluded, the coupled ocean–atmosphere system reflected the ongoing evolution of El Niño.

The forecast, and the record question

The CPC Official ENSO outlook, which the agency says synthesises multiple models from North America and abroad, points to further strengthening before the event begins to weaken in early 2027. That is a model-based expectation, not an observation; the agency frames the peak as still ahead.

CPC also updated the probability it has been tracking for several months: the chance that this event exceeds every El Niño back to 1950, which the centre defines as a three-month Relative Oceanic Niño Index (RONI) value of +2.5 °C or more. Those odds now stand at roughly 60% for both the October–December and November–January seasons — described by CPC as remaining at better than even odds.

The agency attached a caveat to all of this that is easy to lose in the index numbers. Even with a very strong El Niño, CPC wrote, the chances of experiencing impacts consistent with El Niño are higher, though not guaranteed, and it pointed readers to its own seasonal outlooks for probabilities of specific anomalies. In other words, the strength of the Pacific signal raises the odds on the familiar regional patterns without fixing any one outcome.

Where this sits in the sequence

The November discussion continues a run of upward revisions to the Niño indices through the second half of 2026, and keeps the advisory — the alert level CPC uses when El Niño conditions are observed and expected to continue — unchanged. A probabilistic strength forecast is published separately by the centre, which also updates oceanic and atmospheric conditions weekly through its El Niño/La Niña current conditions and expert discussion pages.

The discussion is produced jointly by NOAA, NOAA's National Weather Service and their funded institutions. CPC has scheduled the next ENSO Diagnostics Discussion for 10 December 2026. For background on how the Niño regions and RONI are constructed, see our science and glossary pages.