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: Not Active

 

Outlook:

 

ENSO-neutral is favored (~85% chance during Jul-Sep, decreasing to ~55% during Dec-Feb) through the Northern Hemisphere winter 2017-18.

 

Discussion:  

 

During July, ENSO-neutral continued, as equatorial sea surface temperatures (SSTs) were near average across most of the Pacific Ocean (Fig. T18). The monthly Niño SST index values were between 0.4ºC and -0.1ºC in all four Niño regions (Table T2), having recently decreased from higher levels. The upper-ocean heat content anomaly was near average during July, reflecting below-average temperatures along the thermocline across the central and eastern Pacific overlain by slightly above-average temperatures (Fig. T17). Tropical convection was near average over the eastern half of the Pacific and enhanced over the western Pacific and the Maritime Continent (Fig. T25). The lower-level trade winds were slightly enhanced near the International Date Line, and upper-level winds were near average over most of the tropical Pacific (Fig. T20 & Fig. T21). Overall, the ocean and atmosphere system remains consistent with ENSO-neutral.

The majority of models favor ENSO-neutral through the remainder of 2017 (Figs. F1-F13). These predictions, along with the demise of the recent Pacific warmth and continued near-average atmospheric conditions over the Pacific, lead forecasters to favor ENSO-neutral through the winter. However, some chance for El Niño (15-20%) or La Niña (25-30%) remains during the winter. Also, ENSO-neutral conditions are predicted for the upcoming peak months (August-October) of the Atlantic hurricane season.  In summary, ENSO-neutral is favored (~85% chance during Jul-Sep, decreasing to ~55% during Dec-Feb) through the Northern Hemisphere winter 2017-18.

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