|WA Seasonal Rainfall Outlook: probabilities for February to April 2006, issued 24th January 2006|
50:50 chances for a wetter than average season
The chances of accumulating at least median rain during the late summer to mid-autumn period (February to April) are close to 50% across Western Australia, the Bureau of Meteorology announced today. The outlooks are based on relationships between Pacific and Indian Ocean temperatures and Australian rainfall. Recent ocean temperatures have not been sufficiently warmer or cooler than average to produce a strong bias in rainfall outlook odds.
For the February to April period, the chances of above median rainfall are between 50 and 60% over WA (see map).
So in years with ocean patterns like the current, about five or six February to April periods out of ten are expected to be wetter than the median in Western Australia, with about five or four out of ten being drier.
Outlook confidence is related to how consistently the Pacific and Indian Oceans affect Australian rainfall. During the February to April period, history shows the effect to be moderately consistent through most of WA (see background information).
The Southern Oscillation Index (SOI) rose slightly from −3 in November to a value of +1 in December. The approximate SOI for the 30 days ending 21st January was +10.
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 21st FEBRUARY 2006