The La Niña phenomenon continued during December with above-average rainfall and negative sea surface temperature (SST) anomalies occuring across the central and eastern equatorial Pacific. The low-level easterly winds were slightly enhanced over the western Pacific, and upper-level westerly anomalies were observed across the eastern Pacific. Overall, the ocean and atmosphere system remained consistent with a weak La Niña.
A transition to neutral El Niño–Southern Oscillation (ENSO) levels is expected to occur by February 2017 and continue through the first half of 2017. Even as the tropical Pacific Ocean returns to ENSO-neutral conditions, the atmospheric impacts from La Niña could persist during the upcoming months. – Climate Prediction Centre