The 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 Climate Prediction Center. The
predictions from the National Centers for Environmental Prediction (NCEP) coupled
ocean/atmosphere model (Ji et al. 1998, Mon. Wea. Rev, 126, 1022-1034) are
presented in Figs. F3 and F4a, F4b. Predictions from the Markov model (Xue,
Y. et al. 2000: ENSO prediction with Markov model: The impact of sea level. J. Climate,
13, 849-871) are shown in Figs. F5 and F6.
Predictions from the latest version of the LDEO model (Chen,
D. 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, J. A. and C. W. Landsea 1997, Wea. Forecasting, 12, 633-652) are
shown in Fig. F12. Niño
3.4 predictions are summarized in F13,
which is 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.
Based on current conditions and recent observed
trends, it is likely that slightly warmer-than-average conditions will
persist in the equatorial Pacific through the Northern Hemisphere early
Sea surface temperatures remained warmer than average in the central
and western equatorial Pacific and near average in the eastern
equatorial Pacific during January (Figs T9, T18).
Equatorial ocean surface temperatures greater than +0.5°C
(~1°F) above average were found
between Indonesia and 165°W,
and departures greater than +1°C
were found between 160°E and
175°W (Fig. T18).
Positive SST anomalies decreased in all of the Niño
regions from December to January (Table T2).
At the moment there are no discernable impacts from the anomalously
warm waters on the atmospheric circulation. The monthly 850-hPa zonal
wind indices, OLR index, 200-hPa zonal wind index, SOI and EQSOI have
not shown any significant trends over the last few months that would
support a transition to either El Niño
or La Niña (Table T1,
Fig. T2). However, many of these indices have exhibited considerable
week-to-week variability since late November in response to tropical
intraseasonal (Madden-Julian Oscillation) activity. Wetter-than-average
conditions, observed over the tropical Indian Ocean in late November,
shifted eastward to the western Pacific by late December and into the
central Pacific by early January (Fig. T11). As the convective
activity shifted eastward, the equatorial easterlies weakened over the
western and central Pacific (Fig. T13) and westerlies developed
near the date line (180°W).
During the last half of January the equatorial easterlies intensified,
becoming stronger than average over the central and western equatorial
Pacific, as the convectively inactive phase of the MJO shifted eastward
over the region (Fig. T13).
The weakening of the equatorial easterlies in late December - early
January initiated an eastward propagating oceanic Kelvin wave, which is
evident in the recent evolution of upper ocean temperature anomalies (Figs.
T15, T17). More recent observations from the TAO buoy array indicate
that this Kelvin wave is propagating eastward at about 8-10 degrees of
longitude per week. At that rate, the Kelvin wave is expected to reach
the vicinity of the west coast of South America around the end of
February. NOAA’s Climate Prediction Center (CPC) will continue to
monitor this situation to determine what, if any, impacts the Kelvin
wave will have on surface and subsurface temperatures along the South
A majority of the statistical and coupled model forecasts indicate
near-average conditions in the equatorial Pacific (Niño
3.4 SST anomalies between -0.5°C
and +0.5°C) through the early
Northern Hemisphere spring 2004 (Figs. F1, F2,
F3, F4a, F4b, F5,
F6, F7, F8,
F9, F10, F11,
F12, F13). Thereafter, the
forecasts show increasing spread and greater uncertainty. The
three-month (November-January) average SST anomaly in the Niño
3.4 region (+0.5°C) is at the
threshold (+0.5°C) required for
NOAA to declare a weak Pacific warm episode (El Niño).
However, the SST indices all decreased slightly during January and the
atmospheric indices do not currently reflect warm episode conditions.
Based on current conditions and recent observed trends, it is likely
that slightly warmer-than-average conditions will persist in the
equatorial Pacific through the Northern Hemisphere early spring 2004.
Weekly updates of SST, 850-hPa wind, OLR and features of the
equatorial subsurface thermal structure are available on the Climate
Prediction Center homepage at: