MELBOURNE, Australia – The El Niño–Southern Oscillation (ENSO) is neutral, and with no sign of El Niño or La Niña developing, the ENSO Outlook is inactive, according to the Bureau of Meteorology of the Australian Government (BOM). Climate model outlooks suggest the tropical Pacific Ocean will remain at neutral ENSO levels at least until September.
Tropical Pacific Ocean sea surface temperatures continue at ENSO-neutral values. Below the surface, much of the central to eastern tropical Pacific has warmed over the past few months, and is now at near-average temperatures. Atmospheric indicators are also at neutral ENSO levels.
The Southern Oscillation Index (SOI) is close to zero, while trade winds are mostly near average. Cloudiness near the Date Line has increased in the past week to above-average levels, in contrast to almost all of the preceding 12 months when below-average cloudiness was a feature across the region. The return to ENSO-neutral conditions in autumn is typical of the life cycle of ENSO events.
The Madden–Julian Oscillation (MJO) has been the strongest climate driver influencing Australia during the last fortnight with above average falls in the far northern tropics. The MJO has moved out of the Australian region and into the western Pacific at moderate strength. As it moves across the western Pacific, the MJO typically acts to suppress rainfall over northern Australia at this time of the year.
The Southern Annular Mode (SAM) is expected to remain neutral for the coming fortnight. When SAM is neutral it has little influence on Australian rainfall.
The Indian Ocean Dipole (IOD) is also neutral. It typically has little influence on Australian climate from December to April.
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.
