WA Seasonal Rainfall Outlook: probabilities for April to June 2004, issued 17th March 2004

Neutral June quarter rainfall odds in WA

The Bureau's seasonal rainfall outlook for the June quarter shows a strongly varied pattern in the odds over southern and eastern Australia. However, in WA the rainfall probabilities are neutral for the coming season. This overall outlook pattern is a result of the combined effects of above average temperatures in both the Pacific and Indian Oceans.

For the April to June period, the chances of above median rainfall are between 40 and 50% across Western Australia (see map). So with climate patterns like the current, about 5 seasons out of 10 are expected to be drier than average in WA, with about 5 out of 10 being wetter.

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

Outlook confidence is related to the influence of Pacific and Indian Ocean temperatures on seasonal rainfall. During the June quarter, history shows this influence to be moderately consistent in a broad band stretching from the Pilbara to the southeast and far eastern interior. Elsewhere in WA the influence is only weakly or very weakly consistent (see background information).

Both the Indian and tropical Pacific Oceans remain warmer than average. 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. February's value was +9 following the –12 in January and +10 in December. The approximate SOI for the 30 days ending 14th March was +4.

 

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 19th APRIL 2004.

Corresponding temperature outlook

February 2004 rainfall in historical perspective

December 2003 to February 2004 rainfall in historical perspective

 

Background Information