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 1-3 months.
The patterns of anomalous ocean temperatures, atmospheric circulation and
precipitation are consistent in indicating La Niña conditions in the
tropical Pacific. During March negative equatorial SST anomalies less than –0.5ºC were
observed at most locations between 180ºW and 90ºW (Fig.
T18), and negative SST departures
were observed in all of the Niño regions, except for Niño 1+2 (Table
T2 and Fig. T5). During the month, positive SST
departures decreased in the extreme eastern equatorial Pacific (Fig.
T9), as conditions returned to near average in
that region (Fig. T25).
During March above-average
precipitation (negative OLR anomalies) was observed over Indonesia, the
Philippines, northern Australia and Hawaii, while below-average precipitation
(positive OLR anomalies) was observed over the central equatorial Pacific and
over the eastern tropical Pacific between the equator and 10ºN (Fig.
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
February-March 2006 (Figs.
T15 and T17), and the basin-wide upper ocean heat content, although increasing,
remained below-average. These atmospheric and oceanic features are consistent
with ongoing La Niña conditions.
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 January -
March 2006 is -0.7°C, which
indicates La Niña conditions. Most
of the statistical and coupled model forecasts indicate ENSO-neutral
conditions in the tropical Pacific through the end of 2006 (Figs. F1,
F2, F3, F4a,
F4b, F5, F6,
F7, F8, F9,
F10, F11, F12
The spread of the most
recent statistical and coupled model forecasts (weak La Niña to weak El Niño)
indicates uncertainty in the outlooks for the last half of the year.
However, current conditions
(stronger-than-average easterly winds over the central equatorial Pacific and
below-average upper-ocean heat content) support those forecasts indicating
that La Nina conditions will continue for the next 1-3 months.
updates of SST, 850-hPa wind, OLR and features of the equatorial subsurface
thermal structure are available on the
Center homepage at: