Seasonal Climate Outlook April - June 2009
The rainfall outlook for the period April to June was released by the Bureau of Meteorology on 24 March 2009.
The outlook shows there is a moderate to strong shift in the odds favouring drier than normal conditions over much of Victoria. The chances of exceeding the median rainfall across Victoria are between 35% and 40% across most of the state, with between 40% and 50% in east Gippsland and between 30% and 35% in the north and west.
The Bureau’s latest ENSO Wrap-Up was issued on 11 March 2009. In general, equatorial Pacific temperatures fell short of typical La Niña values and were around 1°C warmer than those observed at the peak of the 2007/08 La Niña. However, other typical La Niña climate patterns persisted during February, most notably the enhanced Walker Circulation in the western Pacific as shown by an SOI of +15, stronger than normal Trade Winds and reduced cloudiness near the date-line. This pattern has been the main factor behind the above average rainfalls across tropical Australia during the wet season.
The majority of dynamic computer models predict neutral conditions to continue until at least mid-winter. The Indian Ocean Dipole is neutral, as is typical for this time of year. It will be monitored in autumn for any signs of an emerging event.