The 2015 El Niño continues to develop. International climate models surveyed by the Bureau of Meteorology suggest further warming of the tropical Pacific is likely, with sea surface temperatures forecast to remain above El Niño thresholds for the remainder of the year.
Most oceanic and atmospheric indicators are consistent with El Niño. Sea surface temperatures in the tropical Pacific have continued to warm, and trade winds have been consistently weaker than average. However, the Southern Oscillation Index (SOI) is currently rising, with this due to local weather, not climate factors. In the past three months the SOI has averaged −9.7, exceeding El Niño thresholds. Cloudiness near the Date Line has also eased towards more normal levels, but this shift may only be short-lived.
El Niño is often associated with below-average winter and spring rainfall over eastern Australia, and above-average daytime temperatures over the southern half of the country. The strength of El Niño doesn't directly relate to the strength of its effects on Australia's climate.
The Indian Ocean Dipole (IOD) is currently neutral. Of the five international models that provide IOD outlooks, two suggest a positive IOD is likely later in 2015, with a third model just shy of thresholds. A positive IOD is typically associated with reduced winter and spring rainfall over parts of southern and central Australia.
Credit to Australian Government Bureau of Meteorology
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