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.

 

ENSO Alert System Status: La Nina Advisory

 

Outlook: La Nina is favored to continue for the next month or two, with a transition to ENSO-neutral most likely in January-March 2026 (68% chance).

 

Discussion:

 

La Nina persisted in November, as indicated by the continuation of below-average sea surface temperatures (SSTs) across the central and eastern equatorial Pacific Ocean (Fig. T18). The monthly Nino-3.4 index value was -0.7C, with the other Nino index values between -0.3C and -0.6C (Table T2). Recent negative subsurface temperature anomalies weakened slightly (averaged from 180-100W), but below-average temperatures continued from the surface to 200m depth in the eastern half of the equatorial Pacific (Fig. T17). The tropical atmosphere reflected La Nina, with low-level easterly wind anomalies evident in the central Pacific and upper-level westerly wind anomalies observed across most of the equatorial Pacific Ocean (Figs. T20 & T21). Enhanced convection persisted over Indonesia and suppressed convection was near the Date Line (Fig. T25). The traditional and equatorial Southern Oscillation indices were positive (Fig. T2). Collectively, the coupled ocean-atmosphere system remains consistent with La Nina.

The IRI multi-model predictions indicate La Nina will continue in the December-February (DJF) 2025-26 season, but then ENSO-neutral is favored for January-March (JFM) 2026 (Figs. F1-F12). Together with the North American Multi-Model Ensemble, the team continues to slightly support a weak La Nina through DJF (54% chance), before transitioning to ENSO-neutral in JFM. Even after equatorial Pacific SSTs transition to ENSO-neutral, La Nina may still have some lingering influence through the early Northern Hemisphere spring 2026 (e.g., CPC's seasonal outlooks). In summary, La Nina is favored to continue for the next month or two, with a transition to ENSO-neutral most likely in January-March 2026 (68% chance; Fig. 7).

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