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.
Outlook
Near-normal conditions are expected in the tropical Pacific through the boreal spring
of 2001.
Discussion
ENSO-neutral atmospheric and oceanic conditions prevailed in the tropical
Pacific during October. Weak negative SST anomalies were evident across the central and
eastern tropical Pacific during the month (Fig. T18), with
little change over the past few months (Fig. T9). The
oceanic thermocline remained somewhat deeper-than-normal in the equatorial west-central
and western Pacific (Fig. T15), with temperatures
averaging around 1°C- 2°C above normal at thermocline depth (Fig.
T17). The dipole pattern of temperature anomalies that has characterized the
subsurface thermal structure in the tropical Pacific since late 1998 continued to weaken
during the month (Fig. T15). This evolution is consistent
with a return towards normal of the subsurface ocean structure across the equatorial
Pacific. In recent months the pattern of tropical convection [as inferred from anomalous
outgoing longwave radiation (OLR)] has been dominated by tropical intraseasonal
(Madden-Julian Oscillation) activity over the eastern Indian Ocean, Indonesia and the
western Pacific (Fig. T11). This activity has also
resulted in considerable month-to-month variability in the strength of the low-level
easterly wind anomalies across the central and west-central tropical Pacific (Figs. T7, T20).
The most recent NCEP statistical and coupled model forecasts (Figs. F1, F2, F3, F4), as well as other available forecasts (Figs. F5, F6, F7, F8, F9),
indicate near-normal conditions through the spring of 2001.
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).
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