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 Forecast System Model (CFS03) are presented in Figs. F3 and
F4a, F4b. Predictions 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 Fig. F12. 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
ENSO Alert System Status: El Niño Watch
El Niño is favored to form
in the next couple of months and continue through the Northern Hemisphere
winter 2018-19 (70-75% chance).
ENSO-neutral continued during September, but with
increasingly more widespread regions of above-average sea surface temperatures
(SSTs) across the equatorial Pacific Ocean (Fig. T18). During September,
the Niño-3.4 and Niño-3 index values were +0.3°C, while the Niño-4 index value was at +0.5°C (Table T2). Positive subsurface temperature
anomalies (averaged across 180°-100°W) increased during the last month, due to
the expansion and strengthening of above-average temperatures at depth across
the equatorial Pacific (Fig. T17). Convection was increasingly
suppressed over Indonesia and around the Date Line (Fig. T25). Low-level westerly
wind anomalies were evident over the western and east-central Pacific, with
some of the strongest anomalies occurring over the eastern Pacific during the
past week (Fig. T20).
Upper-level wind anomalies were easterly over
the east-central Pacific (Fig. T21). Overall, the oceanic and
atmospheric conditions reflected ENSO-neutral, but with recent trends
indicative of a developing El Niño.
The majority of models in the IRI/CPC plume predict El
Niño to form during the fall and continue through the winter (Figs. F1-F13). The official forecast favors
the formation of a weak El Niño, consistent with the recent strengthening of
westerly wind anomalies and positive temperature trends in the surface and
subsurface ocean. In summary, El Niño is favored to form in the next couple
of months and continue through the Northern Hemisphere winter 2018-19 (70-75%
Weekly updates of oceanic and
atmospheric conditions are available on the Climate Prediction Center homepage
Niño/La Niña Current Conditions and Expert Discussions).