|WA Seasonal Rainfall Outlook: probabilities for Autumn 2005, issued 17th February 2005|
Little signal in autumn rainfall odds for WA
The chances of accumulating at least average autumn (Mar-May) rainfall are close to 50% for nearly all of Western Australia, the Bureau of Meteorology announced today. So there are no strong swings in the odds towards either wetter or drier conditions for the coming three months.
A small area on the coast north of Perth is the one exception to the pattern of odds. For the March to May period, the chances of above median rainfall drop to a little below 40% in this area (see map), which means that below median falls have about a 60% chance of occurring.
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 WA, particularly in the southern half of the State (see background information).
The Southern Oscillation Index (SOI) was +2 in January, 10 points up on the 8 in December. The approximate SOI for the 30 days ending 14th February was 11.
For routine updates on the latest data relating to El Niño, together with details on what the phenomenon is and how it has affected Australia in the past, see the ENSO Wrap-Up.
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.
|More information on this outlook is available from 9.00am to 5.00pm (WST) Monday to Friday by contacting the Climate and Consultancy section in the Bureau's Perth Office: (08) 9263 2222.|
THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 18th MARCH 2005