|NSW Seasonal Rainfall Outlook: probabilities for October to December 2004, issued 16th September 2004|
Neutral outlook for NSW December quarter rainfall
There are only small shifts in the odds towards either above or below average rainfall for the December quarter in New South Wales, the Bureau of Meteorology announced today. This means that the chances of accumulating at least average rain over the last three months of 2004 are mostly close to 50% across the State.
However, when looking at the growing season (April-November) as a whole over southern and eastern Australia, widespread below to very much below average falls up to the end of August mean that many places are unlikely to reach their total growing seasonal average by the end of November. The chances of receiving the required rain are widely below 20%, dropping to below 10% along the coast. For more information on the recent dry conditions, see the Drought Statement.
The current pattern of outlook probabilities is due to recent temperature patterns in both the Pacific and Indian Oceans.
Outlook confidence is related to the influence of Pacific and Indian Ocean temperatures on seasonal rainfall. During the December quarter, history shows this influence to be moderately consistent across the western half of NSW, but generally only weakly consistent in the east (see background information).
The chance of a late-developing El Niño event increased over the past month, with several but not all indicators reaching their El Ni˜o thresholds. The mounting evidence includes warming of the central Pacific, reduced Trade Winds in the same area and continued negative values of the Southern Oscillation Index (SOI) which came in at 8 for August. The approximate SOI for the 30 days ending 13th September was 3.
For routine updates on the latest data relating to El Niño, together with details on what the phenomenon is and how it has affected Australia in the past, see the El Niño Wrap-Up.
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|More information on this outlook is available from 9.00am to 5.00pm (EST) Monday to Friday by contacting the Climate and Consultancy section in the Bureau's Sydney Office: (02) 9296 1522.|
THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 19th OCTOBER 2004.