|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 Cane and
Zebiak model (Cane et al. 1986, Nature, 321, 827-832; Zebiak and Cane 1987, Mon.
Wea. Rev., 115, 2262-2278) are shown in Figs. F5 and
F6. Predictions from the modified Cane and Zebiak model (Chen
et al. 1998, Geophys. Res. Let., 103, 2387-2840), referred to in the figures
as LDEO3, 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.
The CPC and the contributors to the Forecast Forum caution
potential users of this predictive information that they can expect only modest skill.
Discussion and Outlook
The overall patterns of oceanic temperatures and
atmospheric circulation during August were consistent with strengthening cold episode
conditions. Sea surface temperatures (SSTs) remained below normal throughout the
equatorial Pacific east of 160°E, with negative anomalies exceeding -1°C between 170°W
and 120°W (Fig. T18 and Table T2).
Accompanying these conditions, weaker-than-normal convection (Fig.
T25) prevailed throughout the equatorial Pacific east of 160°E, and low-level
easterlies remained stronger-than-normal between 150°E and 150°W (Fig. T20). Consistent with the negative SST anomalies, the
oceanic thermocline remained shallower than normal in the eastern equatorial Pacific and
deeper than normal in the western equatorial Pacific (Fig. T16).
Subsurface temperature anomalies near 130°W averaged as much as 5°C below
normal (Fig. T17) for the first time since March 1999.
The positive subsurface temperature anomalies in the west-central equatorial Pacific
continue to show little evidence of an eastward shift indicating that cold episode
conditions are likely to persist in the tropical Pacific for at least the next several
months. This assessment is supported by the most recent NCEP coupled model forecast (Figs.
F3 and F4) and other available
coupled model and statistical model predictions that indicate cold episode
conditions persisting through the Northern Hemisphere spring of 2000.
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