MELBOURNE, Australia – The El Niño–Southern Oscillation (ENSO) remains neutral, with all oceanic and atmospheric indicators within the neutral range, reports the Bureau of Meteorology of the Australian Government in its latest update. Climate model outlooks show this neutral ENSO state is likely to continue until at least spring.
The Indian Ocean Dipole (IOD) is currently neutral, although the index has been below the negative IOD threshold for three consecutive weeks. Large parts of the eastern Indian Ocean are warmer than average, with some cooler than average water near the Horn of Africa.
The consensus of international climate model outlooks suggest the IOD is most likely to remain neutral during the first part of winter, although three of the five models suggest negative IOD conditions could develop over winter or spring.
The accuracy of IOD forecasts is still low in early June but will increase significantly by the end of the month. A negative IOD increases the chances of above average winter–spring rainfall for parts of southern Australia. While a negative IOD event is not declared until the index remains below the threshold for at least 8 weeks, the current pattern can still influence Australian rainfall as the event evolves.
The Madden–Julian Oscillation (MJO) is currently weak or indiscernible. It is forecast to re-appear over the African region during the next fortnight. Its effect on Australia for this period is expected to be weak. At this time of the year, the MJO influence is primarily in the northern hemisphere, and it therefore has less influence on northern Australia.
The Southern Annular Mode (SAM) has been neutral for the past week. It is expected to be positive for the coming fortnight. Positive SAM typically acts to decrease rainfall over south-west and south-east Australia and increase rainfall over parts of eastern Australia.
Climate change continues to influence Australian and global climate. Australia’s climate has warmed by 1.44 ± 0.24 °C over 1910–2019, while southern Australia has seen a reduction of 10–20% in cool season (April–October) rainfall in recent decades.