International climate models surveyed by the Australian Bureau of Meteorology indicate that warming of the tropical Pacific is likely in the coming months, with most models showing temperatures approaching or exceeding El Niño thresholds during the austral winter. In its latest review of the El Niño–Southern Oscillation (ENSO) released todaythe Bureau said that while current conditions remained neutral – neither El Niño nor La Niña, “recent observations indicate that warming of the tropical Pacific is occurring.”
The tropical Pacific Ocean sub-surface has warmed substantially over the past few weeks, which is likely to result in a warming of the sea surface in the coming months. A recent burst of westerly winds over the far western Pacific is the strongest seen since at least 2009 – the last time an El Niño developed.
El Niño is often, but not always, associated with below-average rainfall during the second half of the year across large parts of southern and inland eastern Australia. Daytime temperatures also tend to be above average over southern Australia.
The Indian Ocean Dipole (IOD) is typically too weak to have a significant influence on the Australian climate from December to April. Current model outlooks indicate a neutral IOD through late autumn and early winter. However, the chance of a positive IOD event is elevated during El Niño.
Temperatures world-wide tend to rise considerably under the influence of an El Niño so climate change studiers will be following developments over the next few months with considerable interest.
That graph is from the Skeptical Science website (“Getting skeptical about global warming skepticism”) which makes this comment about the El Niño/La Niña influence on global temperatures:
Climate change “skeptics” sometimes claim that global warming has somehow magically stopped in recent years based on their “cherry picking” short time periods of reduced temperature increase. However, in reality there was a preponderance of El Niño events in the 1990s and a preponderance of La Niña events since 2000, where the former cause short-term surface warming and the latter cause short-term cooling. Accounting for the El Niño/La Niña influence clarifies that human-caused global warming continues unabated.
Some other information on the likelihood of an El Niño developing: