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 the latest coupled model and statistical model
forecasts, warm episode (El Niņo)
conditions are expected to continue to weaken through March 2003,
followed by a return to near-normal conditions during April-October
Warm episode (El Niņo)
conditions continued to weaken during February 2003. Sea-surface
temperature anomalies decreased throughout the central and eastern
equatorial Pacific by as much as 1.5°C
during the month (Figs. T5 and T9),
while equatorial easterly winds were near normal throughout the region (Figs.
T7 and T20). Since
December there has also been a steady decrease in the magnitude and
extent of the positive subsurface temperature anomalies, indicating a
depletion of the excess warmth in the upper ocean of the equatorial
Pacific (Figs. T15 and T17).
This evolution is typical during the decay phase of warm episodes.
In spite of these trends, significant positive SST anomalies
continued during February 2003 in the central equatorial Pacific, with
anomalies greater than +1°C extending from
170°E to 150°W
(Fig. T18). In addition, enhanced
precipitation and cloudiness occurred over this region (Fig.
T25) and some atmospheric circulation indices, such as the SOI,
continued to reflect warm episode (El NiZo)
conditions (Table T1).
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 March 2003 (Figs. F1,
F2, F3, F4,
F5, F6, F7,
F8, F9, F10,
Thereafter, the consensus forecast is for near-normal conditions during
April-October 2003. However, there is a wide spread amongst the
individual forecasts, with some indicating the possibility of continued
weak El Niņo conditions and
others indicating the development of La Niņa
conditions during the last half of 2003. All such models have relatively
low skill during the transition phases of the ENSO cycle. The recent
cooling of the upper ocean (surface and subsurface) in the eastern
equatorial Pacific supports the possibility of the development of La Niņa
later this year.
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).