The El Niño–Southern Oscillation (ENSO) remains neutral, with neither El Niño nor La Niña in the tropical Pacific Ocean. International models suggest it will remain neutral through at least the southern hemisphere winter, says the latest wrap-up from Bureau of Meteorology (BOM) of the Australian Government.
Atmospheric and oceanic indicators of ENSO are generally at near average levels. Sea surface temperatures (SSTs) are close to the long-term average across the tropical Pacific Ocean, and waters beneath the surface are slightly warmer than average. In the atmosphere, the Southern Oscillation Index (SOI) and trade winds are both within the neutral range.
International models suggest the tropical Pacific Ocean will warm slowly over the coming months, but remain ENSO-neutral for the southern hemisphere winter. Only one of eight climate models suggest sea surface temperatures may approach El Niño thresholds by September; the rest maintain ENSO-neutral.
The Indian Ocean Dipole (IOD) is currently neutral. Half of the surveyed climate models suggest the IOD will remain neutral for winter, while the other half predict a negative IOD. However, the present above average SSTs off northwest Australia are a result of reduced cloud cover increasing solar warming.
If this pattern persists, a typical negative IOD response, such as more cloud off northwest Australia, is less likely. During negative IOD events, winter–spring rainfall is typically above average over southern Australia.
