La Niña conditions strengthened across the tropical Pacific Basin during November. Climate models surveyed by the Bureau suggest the La Niña is likely to peak during the next month and last at least until the end of summer.
Atmospheric indicators of ENSO, including the Southern Oscillation Index (SOI), trade winds and cloudiness, all displayed some strengthening over the past fortnight, with the current SOI value of +15 being the highest since the breakdown of the 2010-11 event in May 2011. Similarly, the classic La Niña ocean patterns in the tropical Pacific have become more clearly defined over the past month. Despite this strengthening, the La Niña remains weaker than at the same time in 2010. Australia’s climate has responded to these recent changes, with above average rainfall across large parts of the north and west of the country since October.