National Seasonal Rainfall Outlook: probabilities for Winter 2004, issued 18th May 2004

Winter rainfall odds mostly neutral

The Bureau's winter rainfall outlook shows a pattern of generally neutral odds with no strong swings towards either wetter or drier conditions. One exception is over central SA where the odds tend to favour below average falls. This outlook pattern is a result of the combined effects of above average temperatures in both the Pacific and Indian Oceans.

For the June to August period, the chances of above median rainfall are mainly close to 50% right across the country, with the exception of some districts of SA (see map). So with climate patterns like the current, about five winters out of ten are expected to be drier than average over most of Australia, with about five out of ten being wetter.

probability of exceeding median rainfall - click on the map for a larger version of the map

In SA, the chances of above median winter rain are between 35 and 40% over parts of the Western Agricultural, Northwest Pastoral, and Northern Agricultural districts. This means that a drier than average winter could be expected in about six seasons out of ten with the current climate patterns. However, the outlook reliability is patchy in this region (see below).

Outlook confidence is related to the influence of Pacific and Indian Ocean temperatures on seasonal rainfall. During winter, history shows this influence to be moderately consistent across much of Queensland, the NT, NSW, and Victoria, but generally weakly consistent elsewhere across the country, reaching moderate only in patches (see background information).

Both the Indian and tropical Pacific Oceans remain mostly warmer than average, although the eastern Pacific has cooled. For more detail see the the El Niño Wrap-Up.

The Southern Oscillation Index (SOI) has been trending downwards over recent months with an April value of –15, following zero in March and +9 in February. The approximate SOI for the 30 days ending 15th May was +8.


Click on the map above for a larger version of the map. Use the reload/refresh button to ensure the latest forecast map is displayed.

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 | NSW | Vic | Tas | SA | WA | NT |

Regional commentary is available from the Climate and Consultancy Sections in the Bureau's Regional Offices:
Queensland -(07) 3239 8669 or (07) 3239 8666
New South Wales -(02) 9296 1522
Victoria -(03) 9669 4949
Tasmania -(03) 6221 2043
South Australia -(08) 8366 2664
Western Australia -(08) 9263 2222
The Northern Territory -(08) 8920 3813



Corresponding temperature outlook

April 2004 rainfall in historical perspective

February to April 2004 rainfall in historical perspective


Background Information