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 ENSO‑CLIPER
statistical model (Knaff and Landsea 1997, Wea. Forecasting, 12, 633‑652)
are shown in Fig. F11. Niño 3.4
predictions are summarized in Fig. F12, 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
is favored during the Northern Hemisphere winter 2019-20 (~70% chance),
continuing through spring 2020 (60 to 65% chance).
Discussion:
Near-to-above
average sea surface temperatures (SSTs) were observed in the east-central
tropical Pacific Ocean during October (Fig.
T18).
The monthly SST indices in the westernmost Niño-4 and Niño-3.4 regions
were +1.0°C and +0.6°C, respectively,
while farther east in the Niño-3 and Niño-1+2 regions they were near or below
average (+0.2°C and -0.8°C respectively; Table T2). The subsurface temperature anomalies
(averaged across 180°-100°W) were above average during the month, as a downwelling oceanic Kelvin wave that began in September
continued progressing eastward into the eastern Pacific (Fig. T17). Low-level winds were near average during
October (Fig. T20), while easterly upper-level wind
anomalies were observed over the eastern Pacific (Fig. T21). Finally, tropical convection was suppressed
near the Date Line and also over Indonesia, while somewhat enhanced convection
prevailed over the western Pacific, northeast of Papua New Guinea (Fig. T25). Overall, despite the recent anomalous warming
across the east-central equatorial Pacific, the overall oceanic and atmospheric
system reflected ENSO-neutral.
The
majority of models in the IRI/CPC plume (Figs.
F1-F12) continue to favor ENSO-neutral (Niño-3.4 index between -0.5°C and +0.5°C) through the Northern Hemisphere spring. Many dynamical forecast models, including the
NCEP CFSv2, suggest Niño-3.4 SST index values will remain near +0.5°C during November before decreasing toward zero. Forecasters believe this recent warmth
reflects sub-seasonal variability and is not indicative of an evolution toward
El Niño. The chances for El Niño are
predicted to be near 25% during the winter and spring. In summary, ENSO-neutral is favored during
the Northern Hemisphere winter 2019-20 (~70% chance), continuing through spring
2020.
Weekly
updates of oceanic and atmospheric conditions are available on the Climate
Prediction Center homepage (El
Niño/La Niña Current Conditions and Expert Discussions).