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 June 2004.
Sea surface temperatures were warmer-than-average in the western
equatorial Pacific (Niņo 4 region), near average in the central
equatorial Pacific (Niņo 3.4 and Niņo 3 regions) and
cooler-than-average in the eastern equatorial
Pacific (Niņo 1+2 region) during the
month (Table T2). Positive
SST anomalies greater than +0.5°C (~1°F) were found between 160°E and
150°W, while negative SST anomalies less than -0.5°C were found
between 95°W and the South American coast (Fig. T9,
past several months, positive SST anomalies have persisted in the
west-central equatorial Pacific (150°E-160°W) (Fig. T9),
low-level easterly wind anomalies (enhanced east-to-west flow) have been
observed over the central equatorial Pacific, and low-level westerly
anomalies have persisted over the western equatorial Pacific (Fig.
T13). These features have favored persistent enhanced tropical
convection (negative OLR anomalies) in the region 140°E-180°W (Fig.
T11). The low-level easterly wind anomalies over the central
equatorial Pacific have also contributed to a steeper-than-average
thermocline slope in the upper ocean, which is reflected in the pattern
of subsurface temperature anomalies [positive (negative) in the
central-western (eastern) equatorial Pacific] (Fig. T17). Both
the surface and subsurface temperature fields showed trends toward
near-average conditions (decreased magnitude of the anomalies) during
intraseasonal variability (MJO activity) in recent months has resulted
in week-to-week and month-to-month variability in many atmospheric and
oceanic indices. During mid-June through early July the easterlies
weakened in many areas of the equatorial Pacific, as enhanced convection
shifted eastward from the Indian Ocean to the western tropical Pacific.
The greatest wind and convection anomalies occurred north of the equator
in the western Pacific, associated with two typhoons. It is too early to
determine whether this event will have any significant impact on the
thermal structure of the equatorial Pacific Ocean.
more than half of the statistical and coupled model forecasts indicate
near neutral conditions in the tropical Pacific (Niņo 3.4 SST anomalies
between -0.5°C and +0.5°C) through the northern summer and fall 2004 (Figs.
F1, F2, F3,
F4a, , F4b, F5,
F6, F7, F8,
F9, F10, F11,
F12, F13). The remaining
forecasts indicate borderline El Niņo conditions (Niņo 3.4 SST
anomalies slightly greater than +0.5°C) will develop within the next
Given the recent trends and observed oceanic and atmospheric patterns
discussed above, ENSO-neutral conditions are expected to continue for
the next 3 months (through September 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: