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
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: Not Active
favored through the Northern Hemisphere summer 2013.
During May 2013,
ENSO-neutral continued, as reflected by the persistence of near-average sea
surface temperatures (SSTs) across much of the equatorial Pacific Ocean (Fig.
However, below average SSTs in the eastern Pacific strengthened,
with the monthly Niño-3 and Niño-1+2 indices at -0.7°C and -1.4°C respectively
(Table ). The Niño-3.4 and Niño-4 SST indices remained warmer
than -0.5°C during May. The oceanic heat
content (average temperature in the upper 300m of the ocean) was near average,
but decreased slightly due to the emergence of below-average sub-surface
temperatures in the eastern Pacific (Fig. ).
Across the Pacific, equatorial winds remained near average, except for
weak low-level easterly anomalies in the western Pacific and weak upper-level
westerly anomalies in the western and central Pacific (Figs. and ). Tropical convection remained enhanced over
Indonesia and suppressed over the central Pacific (Fig. ).
Despite a tendency toward cooler conditions, the overall state of the
tropical Pacific was consistent with ENSO-neutral.
The majority of the model
forecasts favor the continuation of ENSO-neutral, with most models predicting
Niño-3.4 index values below zero (Figs. F1-F13). A smaller number of
models (mainly statistical) predict weak La Niña conditions (Niño-3.4 index
less than -0.5°C) as soon as the Northern Hemisphere summer. As a result, the forecast consensus indicates
larger chances for La Niña relative to El Niño, but there still
remains close to a 60% or greater chance of ENSO-neutral through the Northern
Hemisphere summer 2013.
Niño/La Niña Current Conditions and Expert Discussions).