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.
Near-normal or slightly warmer-than-normal conditions are expected in the tropical
Pacific into early 2002
Near-normal atmospheric and oceanic conditions prevailed in the tropical Pacific during
June. SST anomalies averaged less than 1°C at all locations in the tropical Pacific
except along the immediate South American coast where negative anomalies of around -1°C
were found (Fig. T18). The oceanic thermocline remained
deeper-than-normal in the equatorial west-central and western Pacific (Fig. T15), with temperatures averaging up to 4°C above
normal at thermocline depth (Fig. T17). The negative
temperature anomalies that have characterized the subsurface thermal structure in the
eastern Pacific since late 1998 have continued to weaken (Fig. T15).
The pattern of anomalous tropical convection [as inferred from anomalous outgoing longwave
radiation (OLR)] was rather disorganized during the month, with areas of above-normal
precipitation over Indonesia and along the South Pacific Convergence Zone (SPCZ), and
below-normal precipitation near the date line (Fig. T25).
Consistent with this, the low-level winds across the central and western tropical Pacific
were weak (Fig. T20).
Over the past two years there has been a gradual eastward expansion of the area of
positive subsurface temperature anomalies into the central Pacific (Fig.
T15). SSTs near the international date line have gradually warmed and are
now slightly warmer-than-normal for the first time since the 1997-98 El Niño (Figs. T5, T9). This evolution is consistent
with a decay of the subsurface thermal structure that characterizes the mature phase of
cold episodes towards a pre-warm episode state. Thus, it is likely that near-normal or
slightly warmer-than-normal conditions will persist for the remainder of 2001. This
assessment is generally supported by the most recent NCEP statistical (Figs. F1 and F2) and coupled model forecasts (Figs.
F3 and F4), as well as by other
available coupled model and statistical model predictions (Figs. F5,
F6, F7, F8, F9), which indicate near-normal or slightly warmer-than-normal
conditions into early 2002.
Weekly updates of SST, 850-hPa wind, OLR, and the equatorial subsurface temperature
structure are available on the Climate Prediction Center homepage at:
http://www.cpc.ncep.noaa.gov (Weekly Update).