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:

 

The chance of El Niño is at 60-65% during the Northern Hemisphere fall and winter.

 

Discussion:

 

During August 2014, above-average sea surface temperatures (SST) continued across much of the equatorial Pacific (Fig. T18).  The monthly Niño indices were  +0.5°C in Niño-4, +0.2°C in Niño-3.4, +0.5°C in Niño-3, and +1.3°C in Niño-1+2 (Table T2).  Subsurface heat content anomalies (averaged between 180º-100ºW) also increased during the month as above-average subsurface temperatures developed across the central and east-central equatorial Pacific (Fig. T17).  This warming is associated with the downwelling phase of an equatorial oceanic Kelvin wave triggered in July by low-level westerly wind anomalies.  Westerly wind anomalies continued in the central and eastern part of the basin early in August, but weakened by the end of the month (Fig. T13). Enhanced easterly upper-level wind anomalies have prevailed during much of the month, and the Southern Oscillation Index has been negative (Table T1). However, convective cloudiness remained generally near average over most of the region, except for below average cloudiness observed across the central and western Pacific (Fig. T25).  The lack of a coherent atmospheric El Niño pattern and near-average SSTs in the central Pacific indicate a continuation of ENSO-neutral.

Most of the models continue to predict El Niño to develop during September-November and to continue into early 2015 (Figs. F1-F13).  A majority of models and the multi-model averages favor a weak El Niño.  At this time, the consensus of forecasters expects El Niño to emerge during September-October and to peak at weak strength during the late fall and early winter (3-month values of the Niño-3.4 index between 0.5°C and 0.9°C).  The chance of El Niño is at 60-65% during the Northern Hemisphere fall and winter.

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