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 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. 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.
Predictions from the ENSO-CLIPER statistical model (Knaff, J. A. and C. W. Landsea
1997, Wea. Forecasting, 12, 633-652) are shown in Fig. F10.
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 observed oceanic and atmospheric conditions and SST predictions, warm episode
(El Niņo) conditions are expected to continue during the remainder of 2002 and into early
Based on the latest seasonally-averaged sea surface temperature (SST) data, a Pacific
basin wide warm episode (El Niņo) has now developed. During June 2002 SST anomalies
increased to greater than +1°C throughout the equatorial Pacific between 170°E and
105°W (Fig. T18), and subsurface temperature anomalies
increased throughout the central and east-central Pacific (Fig.
T17). While positive SST anomalies in the vicinity of the date line (180°W) have
gradually increased since mid-2001, those in the east-central portion of the basin
(between 140°W and 105°W) gradually increased in early 2002 and rapidly increased during
late May and early June 2002 (Fig. T9). For the first time
since the end of the 1997-98 El Niņo episode the Niņo 3, Niņo 3.4 and Niņo 4 indices
were all greater than +0.5°C during June (Table T2).
The Madden-Julian Oscillation (MJO) continues to be a major source of week-to-week and
month-to-month variability in the atmospheric circulation of the Tropics and subtropics (Figs.
T11, T12, T13).
In spite of this variability, since March 2002 the SOI has been consistently negative (Table T1), with an average value of -0.8 during the last four
months, and the low-level equatorial easterly winds have weakened over the central Pacific
(140-175°W) (Fig. T13). The oceanic
thermocline has deepened east of the date line (180°W) since mid-May (Fig. T15), consistent with the basin-wide weakening of the
low-level equatorial easterly winds. Given the recent strength of the MJO and its period
of about 40 days, it is likely that significant month-to-month fluctuations will continue
to occur in many atmospheric indices used to monitor the ENSO cycle.
The oceanic and atmospheric variables discussed above reflect the presence of warm
episode (El Niņo) conditions. Most statistical and coupled model predictions (Figs. F1, F2, F3, F4, F5, F6, F7, F8, F9, F10) indicate that weak-to-moderate El Niņo conditions will
continue through the end of 2002 and into early 2003. It is important to add that a weak
or moderate El Niņo would feature much weaker global impacts than were experienced during
the very strong 1997-98 El Niņo.
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).