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 an approximately 50-60% chance of El Niño within the late Northern Hemisphere winter and early spring, with ENSO-neutral slightly favored thereafter.

 

Discussion:  

 

            Equatorial sea surface temperatures (SST) remained above average in the western and central Pacific during January 2015 and cooled across the eastern Pacific (Fig. T18).  Accordingly, the monthly Niño indices were +0.5°C in the Niño-3.4 region, +0.9°C in the Niño-4 region, +0.4°C in the Niño-3 region, and -0.4°C in the Niño-1+2 region (Table T2).  Subsurface temperature anomalies across the eastern half of the equatorial Pacific also averaged near zero during the month.  However, an extensive area of positive subsurface anomalies persisted near the Date Line, while negative anomalies were prevalent closer to the surface east of 110°W (Fig. T17).    During the last couple of weeks of January, several aspects of the tropical Pacific atmosphere showed some movement toward El Niño.  However, for the month as a whole, the equatorial low-level winds were mostly near average across the Pacific (Fig. T13), while upper-level easterly anomalies continued in the east-central Pacific (Fig. T21).  Also, convection remained below average near the Date Line and enhanced in the western equatorial Pacific (Fig. T25).  While the tropical Pacific Ocean is at the borderline of El Niño, the overall atmosphere-ocean system remains ENSO-neutral.

Similar to last month, most models predict a weak El Niño (3-month values of the Niño-3.4 index between 0.5°C and 0.9°C) during the Northern Hemisphere late winter and spring (Figs. F1-F13).  The forecaster consensus also favors Niño-3.4 SST index values in excess of 0.5°C within the coming season.  However, climatologically, ocean-atmosphere coupling tends to weaken into the spring, which increases uncertainty over whether El Niño conditions will emerge.  In summary, there is an approximately 50-60% chance of El Niño within the late Northern Hemisphere winter and early spring, with ENSO-neutral slightly favored thereafter.

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