|WA Seasonal Rainfall Outlook: probabilities for April to June 2006, issued 23rd March 2006|
50:50 chances for above average June quarter rainfall
The current seasonal rainfall odds do not strongly favour either wetter or drier than average conditions. Therefore, the chances of accumulating at least median rain during the June quarter (Apr-June) 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 April to June period, the chances of above median rainfall are between 45 and 55% across WA (see map). So in years with ocean patterns like the current, about five June quarters out of ten are expected to be drier than the median over the State, with about five out of ten being wetter.
Outlook confidence is related to how consistently the Pacific and Indian Oceans affect Australian rainfall. During the June quarter, history shows this effect to be moderately consistent in a broad band stretching from the Pilbara to the southeast and far eastern interior. Elsewhere in WA the effect is only weakly or very weakly consistent (see background information).
After rising to +13 in January, the Southern Oscillation Index (SOI) dropped to a reading of zero in February. The approximate SOI for the 30 days ending 20th March was +11. For more information on the SOI and the current status of ENSO, please 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 APRIL 2006