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
ENSO Alert System Status: Not Active
is favored during the Northern Hemisphere fall 2019 (~85% chance), continuing
through spring 2020 (55-60% chance).
sea surface temperatures (SST) were evident in the east-central Pacific Ocean during
most of September, though SST anomalies increased during the past couple of
weeks (Fig. T18).
The monthly SST indices in the westernmost Niño-4 and Niño-3.4 regions
were +0.6C and 0.0C, respectively, and the indices in the easternmost Niño-3
and Niño-1+2 regions remained near-to-below average (-0.2C and -0.8C
respectively; Table T2).
The subsurface temperature anomalies (averaged across 180-100W)
increased during the month partially because a downwelling
oceanic Kelvin wave expanded eastward (Fig.
This wave was triggered by low-level westerly wind anomalies across the
western and central equatorial Pacific Ocean (Fig. T20). At upper-levels, easterly wind anomalies
prevailed over much of the Pacific during September (Fig. T21). Also, the region of suppressed convection
over Indonesia intensified and expanded to the Date Line (Fig. T25). Despite the recent warming, the overall
oceanic and atmospheric system remained consistent with ENSO-neutral.
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 the next month or so before decreasing, but remaining above
zero. Consequently, forecasters believe
the recent oceanic warmth reflects sub-seasonal variability and is not
indicative of an evolution toward El Niño.
However, chances for El Niño remain between approximately 25-30% through
the winter and spring. In summary,
ENSO-neutral is favored during the Northern Hemisphere fall 2019 (~85% chance),
continuing through spring 2020 (55-60% chance).
updates of oceanic and atmospheric conditions are available on the Climate
Prediction Center homepage (El
Niño/La Niña Current Conditions and Expert Discussions).