|National 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 the entire country, 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 mainly between 45 and 50% across Australia, apart from 40 to 45% chances across part of SA, western Victoria and far southwest NSW, and 50 to 55% chances in northwest 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 country, 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 band from northwest WA across SA, the far southwest of NSW and over most of Victoria. Moderate consistency is also evident in southeast Queensland, northeast NSW, eastern Tasmania and patches in the NT. Elsewhere 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.
|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.|
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 21st APRIL 2006