MELBOURNE, Australia – The El Niño–Southern Oscillation (ENSO) remains neutral. However, the Australian Government Bureau of Meteorology’s ENSO Outlook status is at El Niño WATCH, indicating around a 50% chance of El Niño developing in 2017.
Sea surface temperatures (SSTs) in the central and eastern tropical Pacific Ocean have steadily warmed since the start of the year. In waters near the South American coastline, some areas are now at least 3 °C above average.
However, all indicators of ENSO remain within neutral levels. In the atmosphere, recent fluctuations in the Southern Oscillation Index (SOI) can be attributed to movements in the monsoon trough associated with severe tropical cyclone Debbie, and are not indicative of ENSO.
All international models surveyed by the Bureau suggest that the current steady warming of the tropical Pacific Ocean is likely to continue in the coming months.
Seven of eight models indicate that sea surface temperatures will exceed El Niño thresholds during the second half of 2017. However, some caution must be exercised as models have lower accuracy at this time of year.
El Niño is often, but not always, associated with below average winter–spring rainfall over eastern Australia and warmer than average winter–spring maximum temperatures over the southern half of Australia.
The Indian Ocean Dipole (IOD) has little influence on Australia from December to April. Current outlooks suggest a neutral IOD is likely to remain at least through to the end of winter.