The 2015–16 El Niño is in its last stages. Recent changes in the tropical Pacific Ocean and atmosphere, combined with current climate model outlooks, suggest the likelihood of La Niña forming later in 2016 is around 50%, meaning the Bureau’s ENSO Outlook is at La Niña WATCH.
Eastern tropical Pacific sea surface temperatures have cooled significantly in the past fortnight, and are now approaching neutral levels.
As temperatures under the surface are below average, more surface water cooling is expected.
However the atmosphere is only slowly responding to these changes, and hence the Southern Oscillation Index (SOI) and cloudiness near the Date Line continue to fluctuate around El Niño thresholds.
Six of eight international climate models suggest the tropical Pacific Ocean will return to neutral levels within the next month.
By September, seven of eight models suggest La Niña thresholds are likely. However, individual model outlooks show a large spread between neutral and La Niña scenarios.
La Niña is often, but not always, associated with above-average winter-spring rainfall over northern, central and eastern Australia.
Australia’s climate is also being influenced by record warm temperatures in the Indian Ocean.
The warmth in the Indian Ocean may provide extra moisture for rain systems as they cross Australia during the southern autumn
