Seasonal Climate Outlook - July 2011 to September 2011
The Bureau of Meteorology released its rainfall outlook for July to September 2011 on 23 June. The outlook reports that the odds favour a drier than average late winter-early spring period for Victoria and most of south-east Australia. The outlook is based on the recent Pacific and Indian Ocean temperature patterns. The current outlook is the result of cool conditions in the central tropical Pacific, combined with warm conditions in the Indian Ocean.
The Bureau’s latest ENSO Wrap-Up, issued on 22 June, reports that climate indicators across the equatorial Pacific are currently near normal. Ocean temperatures, trade winds, the Southern Oscillation Index (SOI) and cloudiness over the Pacific are all at neutral levels (i.e. neither La Niña nor El Niño).
The influence of the Indian Ocean Dipole (IOD) on Australian rainfall is currently neutral. However, a weakly positive IOD event has been forecast to develop during winter. Positive IOD events in the past have been associated with drier conditions over south-east Australia during the winter and spring months.