|National Seasonal Rainfall Outlook: probabilities for Spring 2004, issued 17th August 2004|
Dry Spring more likely in parts of SA, Vic and NSW
There is a moderate shift in the odds towards below average spring rainfall in central to southeast SA and adjacent parts of western Victoria and NSW, the Bureau of Meteorology announced today.
However, due to the poor or very poor start to the southern growing season (April-November), many places in eastern and southeast Australia, have a less than 20% chance of reaching the total growing seasonal average by the end of November. Along the east coast, the chances drop below 10%. For more information on the recent dry conditions, see the Drought Statement.
Across central to southeast SA, northwest Victoria and the far southwest of NSW, the chances of above median rainfall for spring are below 40%, dropping below 35% in central SA. So in years with ocean patterns like the current, about six or seven spring periods out of ten are expected to be drier than average, with about three or four out of ten being wetter.
In the NT, WA, Queensland and remaining parts of southeast Australia, the chances of above average seasonal rainfall are close to 50:50.
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 spring, history shows this influence to be moderately consistent across most of Queensland, NSW, Victoria and the NT, and parts of SA, northern Tasmania, southwest and far northwest WA (see background information).
The Southern Oscillation Index (SOI) has remained significantly negative for the second successive month, with a July value of 7 following the June reading of 14. The approximate SOI for the 30 days ending 14th August was 12. Consistent with the negative SOI, the central Pacific has been warming over the past few months. However, given historical precedent and the current model guidance, the triggering of an El Niño event during the second half of 2004 is less likely than the persistence of neutral conditions. For more detail see the El Niño Wrap-Up.
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|The following climate meteorologists in the National Climate Centre can be contacted about this outlook: Grant Beard on (03) 9669 4527, David Jones on (03) 9669 4085, Felicity Gamble on (03) 9669 4256|
|Regional versions of this media release are available: | Qld
Regional commentary is available from the Climate and Consultancy Sections in the Bureau's Regional Offices:
THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 16th SEPTEMBER 2004.