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. et al. 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. et al. 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. Niņo
3.4 predictions are summarized in F13,
which is provided by the Forecasting
and Prediction Research Group of the IRI.
The CPC and the contributors to the Forecast Forum caution potential users of
this predictive information that they can expect only modest skill.
observed atmospheric and oceanic conditions and recent trends, ENSO-neutral
conditions are expected to continue for the next 3 months.
and atmospheric conditions in the Pacific basin continued to reflect the
neutral phase of the ENSO cycle during May 2004.
Sea surface temperatures were
warmer-than-average in the western and central equatorial Pacific (Niņo
3.4 and 4 regions) and cooler-than-average in
the eastern equatorial Pacific (Niņo 3 and 1+2 regions) during
the month (Table T2).
SST anomalies greater than +0.5°C (~1°F) were found between 130°E and
170°W, and in portions of the region between 170°W and 120°W, while
negative SST anomalies less than
-0.5°C were found between 120°W and the South American coast (Figs.
the past several months equatorial Pacific SST anomalies have been
largest in the western Pacific, resulting in an enhanced east-west
gradient of SST that has been associated with stronger-than-average
easterly winds over the central equatorial Pacific (Figs. T13,
and enhanced precipitation over the western equatorial Pacific (Figs.
T25, E3). These
conditions are consistent with a steeper-than-average thermocline slope
in the central equatorial Pacific, with positive (negative) subsurface
temperature departures in the western (eastern) portion of the basin (Fig.
more than half of the statistical and coupled model forecasts indicate
near neutral conditions in the tropical Pacific (Niņo 3.4 SST anomalies
and +0.5°C) through the
northern summer and fall 2004 (Figs. F1, F2,
F3, F4, F5,
F6, F7, F8,
F9, F10, F11,
The remaining forecasts indicate that El Niņo conditions will
develop within the next 3-6 months.
The increasing spread of the forecasts during the last half of 2004
indicates greater uncertainty. Given
the recent trends and observed oceanic and atmospheric patterns
discussed above, it is more likely that ENSO-neutral conditions will
continue for the next 3 months (through August 2004). There is considerable uncertainty
about what will happen after August 2004.
Weekly updates of SST, 850-hPa wind, OLR and features of the
equatorial subsurface thermal structure are available on the Climate
Prediction Center homepage at: