El Niño/La Niña Update (October 2016)

Since July 2016, tropical Pacific Ocean surface temperatures have approached or marginally exceeded weak La Niña levels. However, a clear atmospheric component of the El Niño/Southern Oscillation (ENSO) pattern has not become evident until recent weeks. Since early October trade winds have strengthened over the tropical Pacific Ocean, indicating that a La Niña-like atmospheric circulation pattern may be developing. Around half of the climate models surveyed predict that weak La Niña conditions will develop during the last quarter of 2016, while the remaining models suggest a weakening to more clearly defined ENSO-neutral conditions. On the whole, model outlooks and expert opinion indicate that there is a 50-60% probability of weak La Niña conditions forming in the last quarter of 2016, and persisting into the first quarter of 2017. National Meteorological and Hydrological Services will continue to closely monitor changes in the state of ENSO over the coming months.