Seasonal Climate Outlook - July - September 2010
The Bureau of Meteorology released its rainfall outlook for July to September on 23 June. The outlook reports that the chance of Victoria receiving above average rainfall is equally likely as receiving below average rainfall.
The Bureau issued its latest ENSO Wrap-Up on 23 June. The Bureau reports that major indicators are consistent with the developing stages of a La Niña event.
Pacific sea surface temperatures are generally cooler than average in most areas, while the trade winds in the western Pacific have strengthened and the Southern Oscillation Index has remained positive since April. The majority of international computer models are forecasting a continuation of current trends, with a significant likelihood of further ocean cooling beyond La Niña thresholds before the end of the southern winter.
The Bureau reports that historically, 35~40% of El Niño events have been followed by a La Niña event within the same year. The combination of current trends and model outlooks suggests that 2010 is more likely to be a La Niña year than not.