Forecast Forum
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
skill.
ENSO Alert System Status: El Niño Advisory/ La Niña Watch
Outlook:
La Niña is favored to develop
during the Northern Hemisphere summer 2016, with about a 75% chance of La Nina
during the fall and winter 2016-17.
Discussion:
During the past month, sea surface temperature (SST)
anomalies decreased across the equatorial Pacific Ocean, with near-to-below
average SSTs recently emerging in the eastern Pacific (Fig. T18). The Niño
region indices also reflect this decline, with the steepest decreases occurring
in the Niño-3 and Niño-1+2 regions (Table T2). The
surface cooling was largely driven by the expansion of below-average subsurface
temperatures, which extended to the surface in the eastern Pacific (Fig.
T17). While
oceanic anomalies are clearly trending toward ENSO-neutral, many atmospheric
anomalies were still consistent with El Niño, such as the negative equatorial
and traditional Southern Oscillation indices (Table T1 & Fig. T2). Upper-level easterly
winds persisted over the central and eastern Pacific, while low-level winds
were near average (Figs. T20, T21). Enhanced
convection continued over the central tropical Pacific and was suppressed north
of Indonesia (Fig. T25). Collectively, these anomalies reflect a
weakening El Niño and a trend toward ENSO-neutral conditions.
Most models predict the end
of El Niño and a brief period of ENSO-neutral by early Northern Hemisphere
summer (Figs. F1-F13).
The model consensus then calls for increasingly negative SST anomalies
in the Niño 3.4 region as the summer and fall progress. However, there is clear uncertainty over the
timing and intensity of a potential La Niña (3-month Niño-3.4 SST less than or
equal to -0.5°C). The forecaster
consensus favors La Niña onset during the summer, mainly weighting the dynamical
models (such as NCEP CFSv2) and observed trends toward cooler-than-average
conditions. Overall, La Niña is favored to
develop during the Northern Hemisphere summer 2016, with about a 75% chance of
La Nina during the fall and winter 2016-17.
Weekly updates of oceanic and
atmospheric conditions are available on the Climate Prediction Center homepage
(El
Niño/La Niña Current Conditions and Expert Discussions)