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 F4a, F4b. Predictions from the Markov model (Xue, Y., A. Leetmaa,
and M. Ji, 2000: ENSO prediction with Markov model: The impact of sea level. J. Climate,
13, 849-871) are shown in Figs. F5 and F6.
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., 27,
2585-2587) 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. Predictions from the ENSO-CLIPER statistical model
(Knaff, J. A. and C. W. Landsea 1997, Wea. Forecasting, 12, 633-652) are
shown in Fig. F12.
The CPC and the contributors to the Forecast Forum caution potential users of
this predictive information that they can expect only modest skill.
Based on the recent evolution of conditions in the
tropical Pacific and on coupled model and statistical model forecasts,
warm episode (El Niņo)
conditions are expected to continue to weaken through April 2003,
followed by a return to near-normal conditions during May-October 2003.
Warm episode (El Niņo)
conditions continued during January 2003, as equatorial SST anomalies
remained greater than +1°C in
the central equatorial Pacific between 175°E
and 125°W (Fig. T18). In
addition, enhanced precipitation and cloudiness were observed over the
central tropical Pacific (Figs. T25, E3,
E4), and positive subsurface
(Fig. T17) and a deeper-than-average oceanic thermocline (Figs.
T15 and T16) were observed throughout the equatorial Pacific east of
180°W. These conditions are
consistent with mature warm episode conditions.
During January 2003 there were indications that the warm episode is
beginning to weaken. Sea surface temperature anomalies decreased
throughout the eastern equatorial Pacific by as much as 1.5°C
during the month (Fig. T5), while equatorial easterly winds were
near normal throughout the central and eastern equatorial Pacific (Fig.
T7 and T20). Over the past several weeks there has also been a
steady eastward progression of negative subsurface temperature anomalies
(Figs. T15 and T17), indicating a gradual depletion of the excess
warmth in the upper ocean of the equatorial Pacific. This evolution is
typical during the mature phase of warm episodes.
Recent values of atmospheric and oceanic indices, such as the SOI,
850-hPa zonal winds index, Niņo
3.4, Niņo 3, and Niņo
1+2 are all considerably less in magnitude than those observed during
the 1997/98 El Niņo (Figs. T1, T2,
T3, T4, T5). The warming associated with the current event has been
greatest in the central equatorial Pacific (Niņo
4 and Niņo 3.4 regions).
Regions farther east (e.g., Niņo
3 and especially Niņo 1+2)
have warmed much less.
Consistent with current conditions and recent observed trends, most
coupled model and statistical model forecasts indicate that El Niņo
conditions will continue to weaken through April 2003 (Figs. F1,
F2, F3, F4,
F5, F6, F7,
F8, F9, F10,
Thereafter the consensus forecast is for near-normal conditions during
May-October 2003. Those areas of the world usually affected by El Niņo
may continue to experience related impacts during the next 2-3 months.
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).