MELBOURNE, Australia – The El Niño – Southern Oscillation (ENSO) is currently neutral (neither La Niña nor El Niño), reports the Bureau of Meteorology of the Australian Government in its latest update. Oceanic and atmospheric indicators for the tropical Pacific Ocean are at neutral ENSO levels. However, there are some signs El Niño may form later in the year. Therefore, the ENSO Outlook is at El Niño WATCH. This means there is approximately a 50% chance of El Niño in 2023.
International climate models suggest neutral ENSO conditions are most likely to persist through autumn.
From July, all but one of the models indicate El Niño thresholds will be met or exceeded, with all models by August. Current ENSO outlooks extending beyond autumn should be viewed with some caution as they typically have lower forecast accuracy than forecasts made during other times of the year.
When ENSO is neutral, the Pacific Ocean typically exerts little influence on Australian climate patterns. El Niño typically suppresses rainfall in eastern Australia during the winter and spring months.
The Indian Ocean Dipole (IOD) is neutral. A majority of models suggest that a positive IOD event may develop in the coming months. A positive IOD can supress winter and spring rainfall over much of Australia, potentially exacerbating the drying effect of El Niño. Long-range forecasts of IOD made in autumn have lower accuracy than those made at other times of the year.
The Madden-Julian Oscillation (MJO) has recently strengthened and moved into the Western Pacific region. Most climate models forecast this moderately strong MJO pulse to move into the central and eastern Pacific regions in the coming fortnight. While in the Western Pacific, enhanced rainfall across parts of northern Australia and the Southwest Pacific is expected; this influence weakens as the MJO moves further east.
The Southern Annular Mode (SAM) index is currently neutral and is expected to become briefly negative in the coming week before returning to neutral values.
Warmer than average sea surface temperatures persist around most of Australia, particularly around Tasmania and south-west Western Australia.
Climate change continues to influence Australian and global climates. Australia’s climate has warmed by around 1.47 °C over the period 1910–2021. There has also been a trend towards a greater proportion of rainfall from high intensity short duration rainfall events, especially across northern Australia. Southern Australia has seen a reduction of 10 to 20% in cool season (April–October) rainfall in recent decades.
