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: Not Active
is favored (50 to ~55% chance) through the Northern Hemisphere fall 2017.
May, ENSO-neutral continued, though sea surface temperatures (SSTs) were above
average in the east-central Pacific Ocean (Fig.
T18). The monthly Niño index values
were near +0.5°C in most of the Niño regions, except for the easternmost Niño-1+2
region, which was at +0.8°C (Table T2). The upper-ocean heat content
anomaly increased during May, reflecting the expansion of above-average sub-surface
temperatures across the central and eastern Pacific (Fig. T17) in association with a downwelling
oceanic Kelvin wave. While ocean
temperatures were elevated, the atmosphere was close to average. Atmospheric
convection anomalies were weak over the central tropical Pacific and Maritime
Continent (Fig. T25), while the lower-level and
upper-level winds were near average over most of the tropical Pacific (Fig. T20, Fig. T21). Both the Southern Oscillation Index (SOI) and
Equatorial SOI were also near zero (Tables
Overall, the ocean and atmosphere system remains consistent with
models predict the onset of El Niño (3-month average Niño-3.4 index at or
greater than 0.5°C) during the Northern Hemisphere summer (Figs. F1-F13).
However, the NCEP CFSv2 and most of the models from the latest runs of the
North American Multi-Model Ensemble (NMME) are now favoring the continuation of
ENSO-neutral. These predictions,
combined with the near-average atmospheric conditions over the Pacific, have
resulted in slightly more confidence for the persistence of ENSO-neutral (50 to ~55% chance). However, chances
for El Niño remain elevated (35-50%) relative to the long-term average into the
fall. In summary, ENSO-neutral is favored (50 to ~55% chance)
through the Northern Hemisphere fall 2017
updates of oceanic and atmospheric conditions are available on the Climate
Prediction Center homepage (El
Niño/La Niña Current Conditions and Expert Discussions).