MELBOURNE, Australia – According to the latest update from the Bureau of Meteorology of the Australian Government, the El Niño Alert continues, with the development of the phenomenon likely during the Austral spring. When El Niño Alert criteria have been met in the past, an El Niño event has developed around 70% of the time.
Sea surface temperatures (SSTs) in the tropical Pacific are exceeding El Niño thresholds, with climate models indicating this is likely to continue at least through to early 2024. The past fortnight has seen a decrease in Southern Oscillation Index (SOI) values to moderate negative values (more El Niño-like).
However, this strong swing has been due to increased pressure over Australia, with Tahiti close to normal. El Niño is associated with higher than average pressure over Australia and lower than average pressure over Tahiti.
Overall, atmospheric indicators suggest the Pacific Ocean and atmosphere are not yet consistently reinforcing each other, as occurs during El Niño events. El Niño typically suppresses winter–spring rainfall in eastern Australia.
The Indian Ocean Dipole (IOD) is currently neutral. Climate model forecasts suggest a positive IOD is likely to develop during spring. A positive IOD typically decreases winter–spring rainfall for much of Australia and can increase the drying influence of El Niño.
The Madden–Julian Oscillation (MJO) is in the western hemisphere and currently weak. Some climate models are forecasting a moderately strong MJO pulse over the Pacific Ocean in the coming week; this could assist development towards El Niño conditions.
The Southern Annular Mode (SAM) index is currently neutral and is expected to remain neutral for the coming fortnight. A neutral SAM is associated with typical climate conditions for Australia.
The current status of the ENSO Outlook and other climate drivers does not change the long-range forecast of warmer and drier conditions across most of southern and eastern Australia from September to November. The Bureau’s climate model takes into account all influences from the oceans and atmosphere when generating its long-range forecasts.
