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:  La Niña Advisory

 

Outlook:

 

La Niña is expected to transition to ENSO-neutral conditions by the end of April 2012.

 

Discussion:  

 

La Niña weakened during February 2012, as near- to- above average sea surface temperatures (SST) emerged in the eastern equatorial Pacific Ocean (Fig. T18).  However, below-average SSTs persisted in the central Pacific, as indicated by the monthly Niño-3.4 and Niño-4 indices which were near –0.8°C (Table T2).  The oceanic heat content (average temperature in the upper 300m of the ocean) anomalies also weakened notably, as reflected by a shallow lens (0m to ~25m depth) of positive temperature anomalies east of 125°W and by diminished below-average temperatures east of the Date Line (Fig. T17).  These changes are partly associated with strong low-level westerly wind anomalies across the eastern Pacific, which at times reflected the absence of equatorial easterlies in that region (Figs. T20).  Nonetheless, the larger scale atmospheric circulation anomalies continued to reflect the ongoing La Niña.  Enhanced low-level equatorial easterlies persisted over the central and west-central Pacific, while convection remained suppressed in the western and central Pacific, and enhanced over Malaysia and the Philippines (Fig. T25). Collectively, these oceanic and atmospheric patterns reflect a weakening La Niña.

A majority of models predict ENSO-neutral conditions to return during March-May 2012 and to continue through the Northern Hemisphere summer 2012 (Figs. F1-F13).  The rapid weakening of the negative surface and subsurface temperature anomalies during February 2012, combined with the historical tendency for La Niña to dissipate during the Northern Hemisphere spring, lends support to the return of ENSO-neutral conditions in the coming months.  Therefore, La Niña is expected to transition to ENSO-neutral conditions by the end of April 2012.

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