MELBOURNE, Australia – The El Niño – Southern Oscillation (ENSO) is currently neutral, reports the Bureau of Meteorology of the Australian Government in its latest update. Sea surface temperatures (SSTs) in the central Pacific have been cooling since December 2023. This surface cooling is supported by a cooler than average sub-surface in the central and eastern Pacific. During June, the rate of cooling has decreased. Cloud and surface pressure patterns are currently ENSO-neutral.
Climate models suggest that SSTs in the central tropical Pacific are likely to continue to cool for at least the next 2 months. Four of 7 models suggest SSTs are likely to remain at neutral ENSO levels, and the remaining 3 suggest the possibility of SSTs at La Niña levels (below −0.8 °C) from September.
The Bureau’s El Niño – Southern Oscillation Outlook is at La Niña Watch due to early signs that an event may form in the Pacific Ocean later in the year. A La Niña Watch does not guarantee La Niña development, only that there is about an equal chance of either ENSO neutral or a La Niña developing. Early signs of La Niña have limited relevance to mainland Australia and are better reflections of conditions in the tropical Pacific.
While phenomena such as La Niña provide broad indications of the expected climate, the long-range forecast provides better guidance for local rainfall and temperature patterns.
The Indian Ocean Dipole (IOD) is currently neutral, with the latest weekly value close to zero. Predictability of the IOD is low at this time of year, but improves through the winter months. The latest model outlooks indicate that the IOD will remain neutral until at least early spring.
Global sea surface temperatures (SSTs) have been the warmest on record for each month between April 2023 and May 2024. These global patterns of warmth differ to historical global patterns of sea surface temperatures associated with ENSO and IOD; therefore, future predictions based on historical SSTs during past ENSO or IOD events may not be reliable. The Bureau’s long-range forecast provides the best guidance for local climate.
The Southern Annular Mode (SAM) is currently neutral (as of 22 June). Forecasts indicate the index is expected to become positive during late June, before returning to neutral by early July.
The Madden–Julian Oscillation (MJO) is currently weak (as of 22 June) and is expected to remain weak for the coming fortnight, with the possibility of strengthening in the Maritime Continent. A weak MJO has little impact on Australian rainfall.
