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.
The CPC and the contributors to the Forecast Forum caution potential users of
this predictive information that they can expect only modest skill.
A gradual weakening of cold episode (La Niņa) conditions is likely over the next 6
months, with near-normal or slightly cooler-than-normal conditions expected in the
tropical Pacific by the end of the year.
The large-scale oceanic and atmospheric circulation patterns continued to
reflect cold episode conditions in the tropical Pacific during June. Cold episode-related
oceanic features included below normal SSTs in the central and west-central equatorial
Pacific (Fig. T9), 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 western tropical Pacific (Fig. T20), above-normal
precipitation over Indonesia/ Malaysia (Fig. T25), and
suppressed rainfall over the western equatorial Pacific (Fig. T25).
These patterns of anomalous low-level winds and convection have been highly persistent
since late 1998 (Figs. T7 and T8),
consistent with ongoing cold episode conditions.
The most recent NCEP statistical and coupled model forecasts, as well as other
available forecasts, exhibit considerable spread in the evolution of the tropical Pacific
SSTs over the next 3-9 months. The NCEP coupled model forecast (Figs. F3 and F4) and the LDEO forecast (Figs.
F5 and F6) indicate that cold episode
conditions will weaken during the next 3 months, followed by near-normal conditions
through the end of the year. The NCEP statistical model forecast (Figs. F1 and F2) and other available coupled
model and statistical model predictions (Figs. F7, F8, and F9) indicate the continuation of
weak cold episode conditions through the end of 2000, with a return to near-normal
conditions early in 2001. The lack of any rapid evolution in the subsurface thermal
structure and the persistence of low-level easterly anomalies over the central and western
equatorial Pacific continues to support a slower decay of cold episode conditions than is
shown by either the NCEP coupled model or the LDEO model.
Weekly updates of SST, 850-hPa wind and OLR are
available on the Climate Prediction Center homepage at: http://www.cpc.ncep.noaa.gov (Weekly Update).