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.
La Niña conditions are expected to
continue during the next 3-6 months.
The patterns of anomalous ocean temperatures, atmospheric circulation and
precipitation are consistent in indicating La Niña conditions in the
tropical Pacific. During February negative equatorial SST anomalies less than –0.5ºC
were observed at most locations between 165ºE and 115ºW, while anomalies
greater than +0.5ºC were restricted to the region between Indonesia and 155ºE
and in the eastern equatorial Pacific between
100ºW and the South American coast (Fig.
T18). Negative SST departures were observed in
all of the Niño regions, except for Niño 1+2 (Table
T2 and Fig. T5). During February, SST anomalies
increased in the extreme eastern equatorial Pacific (Fig.
T9) and heavy rains occurred in some portions of
T25). Brief warming has been observed at this
time of the year in that region in previous years, including during the cold
(La Niña) episodes of 1999, 2000 and 2001.
During February above-average precipitation (negative OLR anomalies) was
observed over portions of
along the South Pacific Convergence Zone (SPCZ), while below-average
precipitation (positive OLR anomalies) was observed over the central
equatorial Pacific (Fig. T25).
Stronger-than-average low-level (850-hPa) easterly winds (Figs.
T7 and T20) persisted
over the central equatorial Pacific, and anomalous upper-level (200-hPa)
cyclonic circulation centers were observed in both hemispheres (Fig.
T22). The equatorial subsurface temperature
anomaly pattern (negative anomalies in the central and eastern Pacific and
positive anomalies in the western Pacific) persisted during January 2006 (Figs.
T15 and T17), and the
basin-wide upper ocean heat content remained below-average.
Collectively, these atmospheric and oceanic features are consistent
with La Niña conditions in the tropical Pacific.
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 2005 - February 2006 is -0.8°C, which indicates La Niña conditions. Most of the statistical and coupled model forecasts indicate
cooler-than-average conditions in the tropical Pacific through mid-2006.
The spread of the most recent forecasts (weak La Niña
to ENSO-neutral) indicates some uncertainty in the outlooks (Figs. F1,
F2, F3, F4a,
F4b, F5, F6,
F7, F8, F9,
F10, F11, F12
current conditions (stronger-than-average easterly winds over the central
equatorial Pacific and below-average upper-ocean heat content) and recent
trends in observed oceanic conditions support continuation of La Niña
conditions in the tropical Pacific during the next 3-6 months. Based 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 prevail over northern
Pacific) during the next three months.
updates of SST, 850-hPa wind, OLR and features of the equatorial subsurface
thermal structure are available on the
Center homepage at: