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 ocean/atmosphere model (Ji et al. 1998, Mon. Wea. Rev, 126, 1022-1034) are presented in Figs. F3 and F4. Predictions from the latest version of the LDEO model (Chen, D., M. A. Cane, S. E. Zebiak, Rafael Canizares and A. Kaplan, 2000, Geophys. Res. Let., accepted) are shown in Figs. F5 and F6. Predictions using linear inverse modeling (Penland and Magorian 1993, J. Climate, 6, 1067-1076) are shown in Figs. F7 and F8. Predictions from the Scripps / Max Planck Institute (MPI) hybrid coupled model (Barnett et al. 1993, J. Climate, 6, 1545-1566) are shown in Fig. F9.

A gradual weakening of cold episode (La Niña) conditions in the tropical Pacific is expected during the NH winter followed by near-normal conditions through the spring of 2001.

The large-scale oceanic and atmospheric circulation patterns during November were consistent with weak cold episode conditions in the tropical Pacific. Cold episode-related oceanic features included below normal SSTs (negative anomalies up to -1°C) in the central and eastern equatorial Pacific (Fig. T18), and above- (below-) normal subsurface temperatures in the western (eastern) equatorial Pacific (Fig. T17). Related atmospheric features included stronger-than-normal low-level easterly winds over the central and west-central tropical Pacific (Fig. T20), above-normal precipitation over the Phillippines, Indonesia and northern Australia (Fig. T25), and suppressed rainfall over the west-central and central equatorial Pacific (Fig. T25). During November the pattern of tropical convection was strongly influenced by tropical intraseasonal (Madden-Julian Oscillation) activity, especially over the eastern Indian Ocean, Indonesia and the western Pacific (Fig. T11).

A notable feature of the current oceanic conditions is the lack of evolution of the subsurface thermal structure in the tropical Pacific from a pattern that is typical of the mature phase of cold episodes towards a pre-warm episode state. Thus, it is likely that weak cold episode conditions will be present for the next several months. This assessment is supported by the most recent NCEP statistical and coupled model forecasts (Figs. F1, F2, F3, F4), as well as by other available coupled model and statistical model predictions (Figs. F5, F6, F7, F8, F9) that indicate a gradual weakening of cold episode conditions in the tropical Pacific through the NH winter, followed by near-normal SSTs during the spring of 2001.

Based on current conditions in the tropical Pacific, on the NCEP SST predictions, and on results from historical studies on the effects of cold episodes, we expect wetter-than-normal average conditions to prevail over Indonesia, northern Australia, and southern Africa during the NH winter. Due to enhanced MJO activity, we also expect increased rainfall variability in the tropics and subtropics (30°S-30°N) through the period. Over the United States warmer-than-normal average conditions are expected along the southern tier of states from southern California eastward to Florida. Cooler-than-normal average conditions are likely over western and central Canada and in the upper Midwest and Great Lakes.