Seasonal climate summary southern hemisphere (autumn 2005): an exceptionally warm and dry autumn across Australia

Southern hemisphere circulation patterns and associated anomalies are reviewed for the 2005 austral autumn season. Emphasis is given to the Pacific Basin climate indicators and Australian rainfall and temperature patterns. Autumn, and especially April, was remarkable in Australia for the temperature anomalies across the continent during this period. Autumn 2005 was the warmest on record across Australia. Likewise, the Australian mean temperature in April was nearly 1°C above the previous April record, and well above the previous anomaly recorded for any month. Autumn also saw records set across Australia for maximum temperatures and a warmer than average season for minimum temperatures. Both atmospheric and oceanic ENSO indicators were generally neutral throughout the season. With autumn being a key period for development of ENSO events, known triggers such as anomalously warm subsurface temperatures, present at the start of the season, were monitored closely. However, no ENSO event, either warm or cold, was initiated during the season with conditions persisting generally neutral into winter.