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 fall 2019 (~75% chance), continuing through spring 2020 (55-60% chance).

 

Discussion:  

 

During August, ENSO-neutral continued as reflected by near-average sea surface temperatures (SST) across most of the central and eastern equatorial Pacific Ocean (Fig. T18). The monthly Niño-3 and Niño-3.4 indices were -0.1°C and 0.2°C, respectively, with the westernmost Niño-4 region index remaining above average (0.9°C) and the easternmost Niño-1+2 region index remaining below average (-0.4°C; Table T2).  Upper-ocean subsurface temperature anomalies (averaged across 180°-100°W) decreased slightly during the month, with below-average temperatures strengthening in the east-central equatorial Pacific (Fig. T17).  Suppressed tropical convection continued over parts of Indonesia, while near-average convection was evident near the Date Line (Fig. T25).  Low-level and upper-level winds were near average over most of the tropical Pacific Ocean (Figs. T20 & T21).  Overall, oceanic and atmospheric conditions were consistent with 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.  Interestingly, the statistical model averages favor Niño-3.4 values above the El Niño threshold (+0.5°C) during the fall and winter, while the dynamical model average indicates values near +0.2°C.   Forecasters are leaning toward the dynamical model average, which is also supported by the current tendency of the ocean toward cooler conditions.  In summary, ENSO-neutral is favored during the Northern Hemisphere fall 2019 (~75% chance), continuing through spring 2020 (55-60% chance).

Weekly updates of oceanic and atmospheric conditions are available on the Climate Prediction Center homepage (El Niño/La Niña Current Conditions and Expert Discussions).