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
Niño 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.
A transition from ENSO-neutral
to La Niña conditions is possible during the next 2-3 months.
anomalies decreased across the equatorial Pacific east of the date line
during February 2007 (Table T2)
as negative anomalies replaced positive anomalies in the central and east
central equatorial Pacific (Fig. T18).
By the end of the month positive anomalies greater than +0.5ºC along the
equator were restricted to the region between 145ºE
and the date line (180º). The
latest weekly SST departures in the Niño regions were around 0.5ºC
in the Niño 4 region, near 0ºC in the Niño
3.4 region and slightly negative in the Niño 3 and Niño 1+2 regions. The
equatorial upper-ocean heat content (average temperature departures in the
upper 300 m of the ocean) decreased rapidly during December 2006-January
2007, as the upper ocean cooled and negative temperature anomalies developed
(Fig. T15). The recent cooling has
been accompanied by persistent stronger than-average low-level easterly winds
over the central equatorial Pacific (Figs.
T7 and T20).
Collectively, these oceanic and atmospheric
conditions indicate that the warm (El Niño) episode has ended and that
conditions are becoming more favorable for La Niña to develop.
The value of the Oceanic Niño Index (ONI; 3-month
running mean average of SST anomalies in the Niño 3.4 region – computed
using the Extended Reconstructed SST version-2 data set) for December 2006
– February 2007 is +0.8°C, which reflects the weak El Niño conditions
that prevailed during December 2006 and January 2007. Most
of the statistical and coupled models, including the NCEP Climate Forecast
System (CFS), indicate that SST anomalies will continue to decrease during
the next 2-3 months (Figs. F1,
F2, F3, F4a,
F4b, F5, F6,
F7, F8, F9,
F10, F11, F12
and F13). Some
of the forecast models, especially the CFS, indicate a rapid transition to La
Niña conditions during March-May 2007
updates of SST, 850-hPa wind, OLR and features of the equatorial subsurface
thermal structure are available on the
Center homepage at: