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.
Weak La Niña conditions are expected to
continue during the next 3-6 months.
Equatorial SST anomalies greater than +0.5ºC were
restricted to the region between Indonesia and 170ºE during December, while
negative anomalies less than –0.5ºC were observed at most locations
between the date line and the South American coast (Figs.
T9 and T18). The SST
departures in the Niño 3, Niño 3.4 and Niño 1+2 regions were negative,
while weak positive departures were observed in the Niño 4 region (Table
T2 and Fig.
the last several months surface and subsurface temperature anomalies have
decreased in the region between 180ºW and the South American coast (Figs.
T9, T15 and T17).
During the same period persistent stronger-than-average low-level
equatorial easterly winds were observed over the central Pacific (Figs.
T7 and T13).
Since early November there has been a persistent pattern of enhanced
tropical convection near 130ºE (Indonesia) and suppressed convection
near the date line (180ºW) (Figs. T8
and T25). Collectively, the present oceanic and atmospheric anomalies
are consistent with the early stages of a La Niña episode in the tropical
Over the past several months most of the statistical and coupled model
forecasts have trended towards cooler conditions in the tropical Pacific
through mid-2006. The spread of the most recent statistical and
coupled model forecasts (weak La Niña to weak El Niño)
indicates some uncertainty in the outlooks (Figs. F1,
F2, F3, F4a,
F4b, F5, F6,
F7, F8, F9,
F10, F11, F12
However, current conditions
(stronger-than-average easterly winds over the
central equatorial Pacific) and recent cooling trends in observed oceanic
conditions support the continuation of La Nina conditions in the tropical
Pacific during the next 3-6 months.
on current conditions in the tropical Pacific, the most recent SST
predictions, and on results from historical studies on the effects of cold
episodes, we expect wetter-than-normal (drier-than-normal) conditions to
(central equatorial Pacific) during the
remainder of the NH winter. That pattern of tropical precipitation favors a
northward shift in the position of the jet stream over the eastern North
Pacific during winter, which is usually accompanied by drier-than-normal
conditions over southern
given the late onset of La Niña there is considerable uncertainty as to
whether or not typical La Niña impacts will be experienced in the West
during the remainder of NH winter.
updates of SST, 850-hPa wind, OLR and features of the equatorial subsurface
thermal structure are available on the
Center homepage at: