|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.
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
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 17th MARCH 2004.