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Thursday 24 June 2010 MEDIA RELEASE La Niña increasingly likely for 2010According to the Bureau of Meteorology in its latest "ENSO Wrap-up" statement issued today (23 June 2010) a La Niña event is now ‘more likely than not’ to occur this year. Dr Andrew Watkins, Manager of the Bureau’s Climate Prediction Services, said that if recent trends in Pacific climate patterns continued, a La Niña event would be established before the end of winter. The main feature of a La Niña is a broad region of colder than average water centred along the eastern equatorial Pacific. "Computer model forecasts show a significant likelihood of a La Niña in 2010", Dr Watkins noted. However, it is still possible that recent trends may stall without La Niña thresholds being reached. Even if this did occur, parts of Australia may still experience wetter than average conditions, especially if the Southern Oscillation Index (SOI) remains positive. The surface of the equatorial Pacific is currently cooler than average in some areas, while the Southern Oscillation Index (SOI), which is often indicative of pressure patterns over Australia, has been positive since April. The current value of the SOI is around +6. The Bureau will continue to monitor the developing situation and weekly updates of important data are available on the Bureau's ‘ENSO Wrap-Up’ webpage at www.bom.gov.au/climate/enso
Australian ImpactsHistorically, La Niña events have often, but not always, brought above average rainfall to much of Australia, particularly inland eastern and northern regions. Night time temperatures are also usually warmer than average. Tropical Cyclone risk for northern Australia also increases during La Niña events. Widespread wet conditions and flooding events have accompanied a number of La Niña events in the past. Substantial flooding impacted NSW and Queensland in the event of 1998, while the event of 1988-89 saw flooding also occur in SA and Victoria. In general, while La Niña events tend to be wetter than normal for Australia, no two La Niñas have exactly the same impact on local rainfall. So while some regions may experience the typical pattern of heavy rainfall, other regions may miss out altogether. For specific agricultural planning advice related to La Niña impacts, people are advised to contact their State Departments of Agriculture or Primary Industry.
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