|Northern Aust Seasonal Rainfall Outlook: probabilities for April to June 2008, issued 28th March 2008|
Higher June quarter rainfall favoured in eastern Queensland
The northern Australian outlook for total rainfall over the June quarter (April to June), shows a moderate to strong shift in the odds favouring a wetter than normal season over much of the eastern half of Queensland. Elsewhere in northern Australia, the chance of above-normal rainfall are about the same as the chances of below-normal falls.
The pattern of seasonal rainfall odds across northern Australia is a result of continuing higher than average temperatures in the southeastern Indian Ocean, and cooler than average waters across the equatorial Pacific in association with La Niña. More influence has come from the Pacific.
The chances of exceeding the median rainfall over April to June are between 60 and 70% over most of the eastern half of Queensland, approaching 75% in some southern inland areas (see map). So for every ten years with ocean patterns like the current, about six or seven June quarters are expected to be wetter than average in these parts of northern Australia, while about three or four are drier.
Over the rest of northern Australia, the chances of exceeding the three-month median rainfall are between 50 and 60%.
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 over some large patches in a band from the northern NT to southeast Queensland. However, over the majority of northern Australia the effect is only weakly or very weakly consistent. (see background information).
The La Niña event in the Pacific Basin is showing signs of weakening, although computer models indicate it is likely to persist until about the end of autumn. The 30-day value of the Southern Oscillation Index (SOI) was +15 as at 25th March. 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 23rd April 2008