MELBOURNE, Australia – La Niña continues in the tropical Pacific Ocean reports the Bureau of Meteorology of the Australian Government in its latest update. While oceanic indicators, including sea surface temperatures (SSTs), have weakened to ENSO-neutral values, the atmosphere has been slower to respond and remains La Niña-like. Even as La Niña weakens, it can continue to influence global weather and climate.
All models anticipate SSTs in the central Pacific Ocean will warm further, but remain at neutral levels (neither La Niña nor El Niño) until at least mid-autumn. As accuracy is generally lower for long-range ENSO forecasts made during summer, ENSO outlooks that extend past autumn should be viewed with caution.
The Southern Annular Mode (SAM) is neutral but is expected to briefly dip into negative values before remaining neutral for the coming weeks to months. During summer, a negative SAM typically suppresses rainfall over south-eastern Australia.
A strong Madden–Julian Oscillation (MJO) pulse is currently over the western Pacific and is forecast to move into the eastern Pacific next week. While in the western Pacific, it will likely support ongoing monsoonal activity across northern Australia, although its influence will reduce if it moves into the eastern Pacific. An active pulse of the MJO over the Pacific Ocean may reduce trade wind strength and hence further weaken La Niña.
Warmer than average sea surface temperatures persist in an area around Tasmania, south-east Australia, and New Zealand; around the west coast and north-west of Australia; and parts of the Coral Sea. Warmer waters around Australia, especially in the tropics, can result in greater evaporation, humidity, cloudiness, and rainfall.
The Indian Ocean Dipole (IOD) is neutral and has little influence on Australian climate while the monsoon trough is in the southern hemisphere (typically December to April). Outlooks for the IOD beyond April made at this time of the year have low accuracy.
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
