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:

 

Chances increase for El Niño beginning in July-September 2012.

 

Discussion:  

 

During June 2012, ENSO-neutral continued as reflected in both the oceanic and atmospheric anomalies.  However, positive equatorial Pacific sea surface temperature (SST) anomalies have grown, exceeding +0.5°C across the eastern Pacific Ocean by the end of June (Fig. T18). SST anomalies increase moving from the westernmost Niño 4 region to the Niño 1+2 region adjacent to South America, which remained near +1.5°C during the month (Table T2). The oceanic heat content anomalies (average temperature in the upper 300m of the ocean) increased during June, as above-average sub-surface temperatures became more entrenched in the equatorial Pacific (Fig. T17). This warming was consistent with a weakening of the low-level trade winds across the east-central equatorial Pacific, along with a weakening of the persistent pattern of enhanced convection near Papua New Guinea (Figs.T20 and Fig.T25).  The observations are consistent with ENSO-neutral, but reflect a likely progression towards El Niño.

There continues to be a substantial disparity between the statistical and dynamical model SST forecasts for the Niño-3.4 region (Figs. F1-F13).  The dynamical models, including the NCEP Climate Forecast System (CFS), largely favor the development of El Niño by July-September 2012, while the majority of statistical models predict ENSO-neutral through the rest of 2012.  The forecaster consensus largely favors the dynamical model outcome because those models tend to exhibit greater skill emerging from the Northern Hemisphere “spring barrier” (a period of relatively low confidence ENSO forecasts) and also due to the strengthening of observed signals indicating an evolution towards El Niño.  Overall, the forecaster consensus reflects increased chances for El Niño beginning in July-September 2012.

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