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 (CFS03) 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 using linear inverse modeling (Penland and Magorian 1993: J. Climate, 6, 1067‑1076) are shown in Figs. F9 and F10. Predictions from the Scripps / Max Planck Institute (MPI) hybrid coupled model (Barnett et al. 1993: J. Climate, 6, 1545‑1566) are shown in Fig. F11.  Predictions from the ENSO‑CLIPER statistical model (Knaff and Landsea 1997, Wea. Forecasting, 12, 633‑652) are shown in Fig. F12.  Niño 3.4 predictions are summarized in Fig. F13, 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:  El Niño Watch

 

Outlook:

 

There is a 50% chance that El Niño conditions will develop during the second half of 2012.

 

Discussion:  

 

ENSO-neutral conditions prevailed in May 2012, following the dissipation of La Niña in April. Sea surface temperatures (SSTs) are currently near average across most of the equatorial Pacific Ocean, and above-average in the far eastern Pacific (Fig. T18). The Niño 4 and Niño 3.4 indices were near zero or slightly negative during May, while the Niño 3 and Niño 1+2 indices remained positive (Table T2). The oceanic heat content (average temperature in the upper 300m of the ocean) anomalies became more strongly positive in May, as above-average sub-surface temperatures became established across most of the central and eastern equatorial Pacific (Fig. T17). The low-level trade winds and convection over the central equatorial Pacific were near average during May, although convection remained enhanced over portions of the western Pacific (Figs. T20 and T25). Collectively, these oceanic and atmospheric patterns indicate ENSO-neutral conditions.

The extensive volume of above-average sub-surface water temperatures indicates that the tropical Pacific SST anomalies will likely warm further in the coming months. A majority of models predict ENSO-neutral to continue through the June-August (JJA) season (Figs. F1-F13). Thereafter, most of the dynamical models predict El Niño to develop during JAS, while the statistical models tend to favor the continuation of ENSO-neutral. Thus, there remains uncertainty as to whether ENSO-neutral or El Niño will prevail during the second half of the year. The evolving conditions, combined with model forecasts, suggest that ENSO-neutral and El Niño are roughly equally likely during the late northern summer and fall. The CPC/IRI forecast calls for ENSO-neutral conditions through JAS, followed by an approximately 50% likelihood for El Niño during the remainder of the year.

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