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
. The predictions from the National Centers for
Environmental Prediction (NCEP) Coupled Forecast System Model (CFS03) are
presented in Figs. F3 and F4a,
from the Markov model (Xue, et al. 2000: J. Climate, 13,
849‑871) are shown in Figs. F5 and F6.
Predictions from the latest version of the LDEO model (Chen 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 and
Landsea 1997, Wea. Forecasting, 12, 633‑652) are shown in
Niņo 3.4 predictions are summarized in Fig. F13,
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.
conditions are expected to continue during the next 2 months, with ENSO-neutral
or La Niņa conditions equally likely thereafter.
conditions continued in the tropical Pacific during June 2007, with average
to below-average sea surface temperatures (SSTs) extending from the date line
to the west coast of South America (Fig. T18).
The latest weekly SST departures are similar to values observed last
month, remaining negative in the Niņo 1+2 (-1.4ēC) and Niņo 3 (-0.5 ēC)
regions, and near zero in the Niņo 3.4 (0.1 ēC) and Niņo 4 (+0.4ēC)
regions (Table T2).
evolution toward La Niņa conditions slowed during June 2007.
The upper-ocean heat content (average temperatures in the upper 300 m
of the ocean) remained below-average, but departures were less negative
consistent with the increasing temperatures at thermocline depth (Fig.
The low-level easterly winds remained stronger than average in the
west-central equatorial Pacific (Figs.
T7 and T20),
with suppressed convection along the equator and a weak area of enhanced
convection observed over parts of
these oceanic and atmospheric patterns are consistent with ENSO-neutral
value of the Oceanic Niņo Index (ONI; 3-month running mean average of SST
anomalies in the Niņo 3.4 region computed using the Extended
Reconstructed SST version-2 data set) for April-June 2007 is
0.0°C, which reflects ENSO-neutral conditions in the tropical
Pacific. Nearly all of the
model forecasts predict below-average SSTs in the Niņo 3.4 region (5°N-5°S,
120-170°W) during the remainder of the year (Figs. F1,
F2, F3, F4a,
F4b, F5, F6,
F7, F8, F9,
F10, F11, F12
and F13). A
majority of the statistical models indicate ENSO-neutral conditions
persisting through the summer months, with several statistical models
forecasting weak La Niņa conditions during the fall or winter. In
contrast, most dynamical models, including the NCEP Climate Forecast System (CFS),
continue to predict a transition to La Niņa within the next three months.
However, several of the dynamical models have recently been predicting a
stronger and more rapid cooling than has actually occurred. Therefore,
the statistical models in combination with recent trends in the surface and
subsurface ocean temperatures suggest either a slower evolution toward La Niņa
or the continuation of ENSO-neutral conditions through the remainder of the
updates of SST, 850-hPa wind, OLR and features of the equatorial subsurface
thermal structure are available on the
Center homepage at: