National Seasonal Rainfall Outlook: probabilities for October to December 2003, issued 16th September 2003

Wetter in northeast and west, drier in far southeast

The Bureau's rainfall outlook for the December quarter shows that wetter conditions are favoured in the northeast and west of the country. In contrast, the last three months of the year are more likely to be drier than average in the far southeast. This outlook is largely the result of higher than average temperatures in the Indian Ocean.

For the October to December period, the chances of above median rainfall are between 60 and 70% over most of central and northern Queensland, and between 60 and 75% across a large part of central and western WA (see map). So with climate patterns like the current, about 7 seasons out of 10 are expected to be wetter than average in these parts of the country, with about 3 out of 10 being drier.

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

Through Victoria's southern fringe, parts of Tasmania and the far southeast of SA, the chances of above median seasonal rain are between 35 and 40%. So with climate patterns like the current, about 6 seasons out of 10 are expected to be DRIER than average in these areas, with about 4 out of 10 being wetter.

In northern Victoria, most of NSW, SA and the NT, the odds for above average seasonal falls are close to 50:50.

Outlook confidence is related to the influence of Pacific and Indian Ocean temperatures on seasonal rainfall. During October to December, history shows this influence to be moderate across most of Australia. The influence is weak or very weak across the northeast quarter of NSW and adjacent inland areas of southeast Queensland, as well as over far western SA and areas around the WA/NT/SA border (see background information).

The tropical Indian Ocean is currently warmer than average, whilst the Pacific is showing near normal temperatures. For more detail see the El Niño Wrap-Up. The excess warmth in the Indian Ocean has had the greater influence on the overall pattern of probabilities.

August's value of the Southern Oscillation Index (SOI) was –2, five points below the July value of +3. The approximate SOI for the 30 days ending 13th September was –1.


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, Janita Pahalad on (03) 9669 4859, 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



August 2003 rainfall in historical perspective

June to August 2003 rainfall in historical perspective


Background Information