Seasonal climate summary southern hemisphere (autumn 2012): The transition from La Niña to neutral

Abstract

Southern hemisphere circulation patterns and associated anomalies for austral autumn 2012 are reviewed, with an emphasis on Pacific Basin climate indicators and Australian rainfall and temperatures. Autumn 2012 was a period of transition, with the La Niña event that had developed in spring 2011 ending in late March 2012. This was reflected by most Pacific Basin climate indicators, which shifted toward neutral values through autumn. Northern and eastern parts of Australia were wetter and cooler than normal, largely due to a very strong burst of the Madden-Julian oscillation in March and the tail end of the La Niña. In contrast, large areas of southwest Australia were much drier and warmer than usual. Tasmania was also warmer than normal, despite above average rainfall.