|Northern Aust Seasonal Rainfall Outlook: probabilities for Spring 2008, issued 26th August 2008|
Neutral outlook for spring rainfall
The northern Australian outlook for total spring (September to November) rainfall is neutral, with the odds close to 50:50 for a wetter than normal season.
The pattern of seasonal rainfall odds across Australia is mainly a result of continued warmth in the central and southeastern Indian Ocean, especially off the west coast of WA.
The chances of exceeding the median rainfall for spring are mainly between 45 and 55% over northern Australia, with probabilities a little over 55% in southeast Queensland (see map). So for every ten years with ocean patterns like the current, about five springs are expected to be wetter than average across the NT and QueenslandWA, while about five are drier.
Outlook confidence is related to how consistently the Pacific and Indian Oceans affect Australian rainfall. During spring, history shows this effect to be moderately consistent across most of the NT and Queensland, with the exceptions of the central NT and southeast Queensland where it is only weakly consistent (see background information).
The approximate 30-day value of the Southern Oscillation Index (SOI) was +3 as at 23 August, while a mixed pattern of warmer and cooler than normal temperatures persists along the equatorial Pacific Ocean. Both these observations indicate a neutral climate pattern across the Pacific, which computer models indicate is likely to continue for the next few seasons. For routine updates and comprehensive discussion on any developments 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 Monday to Friday from 9.00am to 5.00pm local time by contacting the Bureau's Climate Services sections in Queensland and the Northern Territory at the following numbers:
THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 25th September 2008