National Seasonal Rainfall Outlook: probabilities for Autumn 2004, issued 17th February 2004

Mostly neutral autumn rainfall odds, except in WA

The Bureau's autumn rainfall outlook generally shows no strong swings in the odds towards wetter or drier conditions. In WA however, a drier than average autumn is more likely in the southwest, whereas above average falls are more likely further north in parts of the Pilbara and Gascoyne. The outlook probabilities have arisen from the combined effects of above average temperatures in both the Pacific and Indian Oceans.

For the March to May period, the chances of above median rainfall are mainly between 35 and 40% in southwest WA (see map), meaning BELOW median falls have a 60 to 65% chance of occurring. So with climate patterns like the current, about 6 seasons out of 10 are expected to be drier than average in this area, with about 4 out of 10 being wetter. Conversely, the chances of above median falls are slightly above 60% over some of the areas to the south and southeast of Karratha.

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

Across Queensland, NSW and the ACT, Victoria, Tasmania, SA and the NT, the chances of a wetter than average autumn generally vary between 45 and 60%.

Outlook confidence is related to the influence of Pacific and Indian Ocean temperatures on seasonal rainfall. During autumn, history shows this influence to be moderately consistent across much of the north and west of the country. Elsewhere the influence is only weakly or very weakly consistent (see background information).

Both the Indian and tropical Pacific Oceans remain warmer than average, the former having a warming trend during January. For more detail see the the El Niño Wrap-Up.

The Southern Oscillation Index (SOI) has shown strong month-to-month variations recently, in association with active and inactive phases of the northern Australian monsoon. January's value was –12 which followed the +10 recorded in December. The approximate SOI for the 30 days ending 14th February was +3.


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

January 2004 rainfall in historical perspective

November 2003 to January 2004 rainfall in historical perspective


Background Information