Forecast Forum

The canonical correlation analysis (CCA) forecast of SST in the central Pacific (Barnett et al. 1988, Science, 241, 192‑196; Barnston and Ropelewski 1992, J. Climate, 5, 1316‑1345), is shown in Figs. F1 and F2. This forecast is produced routinely by the Prediction Branch of the Climate Prediction Center. The predictions from the National Centers for Environmental Prediction (NCEP) Coupled Forecast System Model (CFSv2) are presented in Figs. F3 and F4a, F4b. Predictions from the Markov model (Xue, et al. 2000: J. Climate, 13, 849‑871) are shown in Figs. F5 and F6. Predictions from the latest version of the LDEO model (Chen et al. 2000: Geophys. Res. Let., 27, 2585‑2587) are shown in Figs. F7 and F8. Predictions from the ENSO‑CLIPER statistical model (Knaff and Landsea 1997, Wea. Forecasting, 12, 633‑652) are shown in Fig. F9. Nino 3.4 predictions are summarized in Fig. F10, provided by the Forecasting and Prediction Research Group of the IRI.

The CPC and the contributors to the Forecast Forum caution potential users of this predictive information that they can expect only modest skill.

 

Notice: As of 1 February, 2026, sea surface temperature anomalies are now based on relative sea surface temperature anomalies for ENSO monitoring and forecasting. See NWS Public Information Statement 26-05.

 

ENSO Alert System Status: El Nino Advisory

 

Outlook: El Nino is strengthening, with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27.

 

Discussion:

 

El Nino strengthened further over the past month, with sea surface temperature anomalies exceeding +3.0C in the eastern equatorial Pacific (Fig. T18a). Except for the Nino-4 index, which decreased to +0.1C in August, values in the other Nino indices increased, reaching +1.8C in Nino-3.4, +2.5C in Nino-3, and +3.4C in Nino-1+2 (https://www.cpc.ncep.noaa.gov/data/indices/rel_mthsst9120.txt). The equatorial subsurface temperature index (average from 180-100W) remained steady during August, reflecting a deeper-than-average thermocline (Fig. T17). Subsurface temperatures continued to be significantly above average, with widespread anomalies in excess of +10.0C at depth. Low-level westerly wind anomalies and upper-level easterly wind anomalies extended from the western to the east-central equatorial Pacific (Figs. T20 & T21). Enhanced convection and rainfall persisted from the central to the eastern Pacific, while anomalies remained suppressed over Indonesia (Fig. T25). The traditional and equatorial Southern Oscillation indices remained negative (Figs. T1 & T2). Collectively, the coupled ocean-atmosphere system reflected a strengthening El Nino.

The CPC Official ENSO outlook, which synthesizes multiple models from North America and abroad, indicates El Nino will continue to strengthen through the end of the year. During the October-December 2026 season, there is a 75% chance of a historic event that would exceed the strength of previous El Nino events dating back to 1950 (+2.5C or more for a 3-month RONI value). With an event of this magnitude, the chances of experiencing impacts consistent with El Nino are larger, though not guaranteed (see CPC outlooks for probabilities of seasonal anomalies). In summary, El Nino is strengthening, with a greater than 90% chance of a very strong event during the Northern Hemisphere fall and winter 2026-27.

Weekly updates of oceanic and atmospheric conditions are available on the Climate Prediction Center homepage (El Nino/La Nina Current Conditions and Expert Discussions).