Sea Surface Temperature and ENSO Outlook
for May - October 2019
(Issued: 25 Apr, 2019)
Positive SST anomalies are likely to remain across most of the tropical Pacific Ocean for May – October 2019. Five out of six dynamical coupled models predict a Niño3.4 index exceeding +0.6oC to persist through the whole forecast period. Slightly warmer and cooler than normal SSTs over the western and eastern Indian Ocean are expected for the same period, which correspond to the weak positive phase of the Indian Ocean Dipole index. In summary, based on the running 3-month mean Niño3.4 index, the APCC ENSO outlook suggests about 90% probability of El Niño conditions, with a weak El Niño level (~53% probability) for May – July 2019, gradually decreasing to 70% for August – October 2019.
Fig. 1. Predicted Niño 3.4 Index from individual models (A, B, C, D, E, and F) and the Multi-Model Ensemble (MME).
Fig. 2. Predicted Indian Ocean Dipole mode index (IODMI) from individual models (A, B, C, D, E, and F) and the MME.
Fig. 3. Multi-model ensemble (MME) forecasts of SST anomalies for May - July 2019 (top) and August - October 2019 (bottom). Anomalies are computed with respect to the common base period of participating models in the APCC MME prediction (1983-2010).
Fig. 4. Probabilistic ENSO forecasts based on 3-month mean Nino 3.4 index for May – October 2019.