Bureau of Meteorology of Australia: The 2011–12 La Niña reaches its end

Bureau of Meteorology of Australia: The 2011–12 La Niña reaches its end

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Published

23 March 2012
Press Release Number:
N/A

The 2011–12 La Niña event has ended, with key indicators returning to neutral (neither El Niño nor La Niña) levels. Climate models surveyed by the Bureau of Meteorology suggest that neutral conditions will persist until at least early winter.

Key Pacific Ocean indicators are now at neutral levels, with values similar to those last seen in August 2011. Likewise, atmospheric indicators such as cloudiness, trade winds and the Southern Oscillation Index (SOI) have also returned to near-normal values for this time of year. Despite the 2011–12 La Niña not commencing until far later than normal (spring), the decline has been fairly typical of past events, with a peak in January and a return to neutral conditions during autumn.

The demise of the La Niña does not mean the risk of wet conditions (or tropical cyclones) over Australia has ended. While sea surface temperatures around the continent remain warmer than normal and the tropical wet season is active, there remains a risk of above average rainfall over Australia.

The Indian Ocean Dipole (IOD) has limited influence on Australian rainfall from December through to April. Neutral IOD conditions are forecast for the southern hemisphere winter.

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