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 Watch

 

Outlook: La Nina conditions are most likely to emerge in November 2024 - January 2025 (59% chance), with a transition to ENSO-neutral most likely by March-May 2025 (61% chance).

 

Discussion:

 

ENSO-neutral continued in November, with near-average sea surface temperatures (SSTs) observed across the central and eastern equatorial Pacific Ocean (Fig. T18). The monthly Nino indices ranged from +0.3C (Nino-1+2) to -0.1C (Nino-3.4; Table T2). Below-average subsurface ocean temperatures persisted across the east-central and eastern equatorial Pacific Ocean (Fig. T17). Over the western and central equatorial Pacific, low-level wind anomalies were easterly and upper-level wind anomalies were westerly (Figs. T20 & T21). Convection was suppressed over the Date Line and was enhanced over western Indonesia (Fig. T25). The traditional and equatorial Southern Oscillation indices were positive (Figs. T1 & T2). Collectively, the coupled ocean-atmosphere system reflected ENSO-neutral.

The dynamical models in the IRI plume continue to predict a weak and a short duration La Nina, as indicated by the Nino-3.4 index values less than -0.5C (Figs. F1-F12). This prediction is also reflected in the latest North American Multi-Model Ensemble (NMME), which continues to predict slightly cooler SSTs and weak La Nina conditions.  The forecast team leaned toward predicting an eventual onset of weak and short-lived La Nina conditions, based on the model guidance and current atmospheric anomalies. Weak La Nina conditions would be less likely to result in conventional winter impacts, though predictable signals could still influence the forecast guidance (e.g.,CPC's seasonal outlooks). In summary, La Nina conditions are most likely to emerge in November 2024 - January 2025 (59% chance), with a transition to ENSO-neutral most likely by March-May 2025 (61% chance).

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