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
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
ENSO Alert System Status: El Niño Watch
El Niño conditions are likely to develop during
continued during August 2012 despite above-average sea surface temperatures
(SST) across the eastern Pacific Ocean (Fig. T18). Reflecting
this warmth, most of the monthly Niño index values remained near +0.5°C (Table
oceanic heat content (average temperature in the upper 300m of the ocean)
anomalies also remained elevated during the month, consistent with a large
region of above-average temperatures at depth across the equatorial Pacific (Fig.
signs of El Niño development in the atmosphere included upper-level easterly
wind anomalies and a slightly negative Southern Oscillation Index (Table
T1). Despite these indicators, key aspects of the
tropical atmosphere did not support the development of El Niño conditions
during the month. In particular,
low-level trade winds were near average along the equator, and the pattern of
tropical convection from Indonesia to the central equatorial Pacific was
inconsistent with El Niño with the typical regions of both enhanced and
suppressed convection shifted too far west (Figs.T20 and T25). Because of the lack of
clear atmospheric anomaly patterns, ENSO-neutral conditions persisted during
August. However, there are ongoing signs of a possibly imminent transition
towards El Niño in the atmosphere as well as the ocean.
Most of the dynamical
models, along with roughly one-half of the statistical models, now predict the onset of El Niño beginning in August-October 2012,
persisting through the remainder of the year (Figs. F1-F13). The consensus of
dynamical models indicates a borderline moderate strength event (Niño 3.4 index
near +1.0°C), while the statistical model consensus indicates a borderline weak
El Niño (+0.4° to +0.5°C). Supported by the model forecasts and the continued
warmth across the Pacific Ocean, the official forecast calls for the
development of most likely a weak El Niño during September 2012, persisting
through December-February 2012-13.
updates of oceanic and atmospheric conditions are available on the Climate Prediction
Center homepage (El
Niño/La Niña Current Conditions and Expert Discussions).