Forecast Forum - March 1999
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 Cane and Zebiak model (Cane et al. 1986,
Nature, 321, 827-832; Zebiak and
Cane 1987, Mon. Wea. Rev., 115, 2262-2278) are shown in
Figs. F5 and F6. Predictions from the
modified Cane and Zebiak model (Chen et al. 1998,
Geophys. Res. Let., 103, 2387-2840), referred to in the
figures as LDEO3, 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
The CPC and the contributors to the Forecast Forum
caution potential users of this predictive information that they can expect only modest skill.
Discussion and Outlook
Cold episode conditions continued in the tropical Pacific during March. As in previous months,
sea surface temperatures (SSTs) were well below normal across the central and east-central equatorial
Pacific (Fig. T18 and Table T2). Negative subsurface temperature anomalies (Fig. T17) and a shallower
than normal oceanic thermocline continue to dominate the equatorial Pacific with the thermocline more than 30
m shallower than normal from 150° W to 115° W (Fig. T16). Accompanying these conditions, the mean
low-level equatorial easterly winds remained much stronger than normal over the central tropical Pacific and
near normal over the eastern Pacific (Fig. T20). At upper levels, enhanced westerlies were found over much
of the central tropical Pacific (Fig. T21). These conditions contributed to a vigorous Walker circulation
over the equatorial western and central Pacific (Fig. T29). The pattern of anomalous precipitation as
inferred from the anomalous Outgoing Longwave Radiation (OLR), indicated enhanced convection over the
eastern Indian Ocean, Indonesia, and the Philippines and suppressed convection over the remainder of the
equatorial Pacific east of New Guinea (Fig. T25). This pattern has been very persistent since
SeptemberNovember 1998 (Fig. T8
), consistent with cold episode conditions.
The latest NCEP statistical (Figs. F1 and F2
) and coupled model forecasts (Figs. F3 and F4) indicate that cold episode conditions in the tropical Pacific will likely continue for the next three months.
Other statistical and coupled model forecasts are consistent with the NCEP models through this period.
The dynamical and statistical model forecasts exhibit considerable variability thereafter, which is also
a period of climatologically low skill.
Weekly updates of SST, 850-hPa wind and OLR are available on the Climate Prediction
Center homepage at: http://www.cpc.noaa.gov (La Niña / Weekly Update).