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: Not Active
Outlook:
ENSO-Neutral
conditions are slightly favored (between 55-60%) during the upcoming Northern
Hemisphere fall and winter 2016-17.
Discussion:
ENSO-Neutral
conditions were observed over the past month, although sea surface temperatures
(SSTs) were below-average over the east-central equatorial Pacific Ocean (Fig.
T18). While the Niño-3.4 and Niño-3 regions were -0.5°C
for the month, Niño-4 and Niño 1+2 were 0.0°C and +0.4°C, respectively (Table
T2). Subsurface
temperatures across the eastern and central Pacific remained below average, and
negative temperature anomalies remained weak across the western Pacific (Fig.
T17). Atmospheric anomalies over the tropical Pacific
Ocean largely indicated ENSO-Neutral conditions. The traditional Southern
Oscillation index and the equatorial Southern Oscillation index were weakly
positive during August (Table T1
& Fig. T2). The lower-level winds were near
average, while the upper-level winds were anomalously westerly in a small
region to the east of the International Date Line (Figs. T20, T21). Convection was suppressed over the western
and central tropical Pacific, although less suppressed compared to last month (Fig.
T25). Overall, the combined ocean and atmosphere system
continues to reflect ENSO-Neutral.
The
multi-model averages favor borderline Neutral-La Niña conditions (3-month
average Niño-3.4 index less than or equal to -0.5°C) during the Northern
Hemisphere fall, continuing into winter (Figs.
F1-F13). However, the more recently updated model runs
from the North American Multi-Model Ensemble (NMME) more strongly favor ENSO-Neutral.
The forecaster consensus prefers this outcome, which is supported by the lack
of significant anomalies in several indicators over the past month (winds,
convection, subsurface temperatures). Overall, ENSO-Neutral conditions are slightly favored (between 55-60%) during the
upcoming Northern Hemisphere 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).