|Southeastern Aust Seasonal Rainfall Outlook: probabilities for February to April 2008, issued 24th January 2008|
Seasonal rainfall odds near 50:50 in southeast Australia
For southeastern Australia, the outlook for late summer to mid-autumn (February to April) shows no strong swings in the odds towards below or above median rainfall.
The pattern of seasonal rainfall odds across southeast Australia is a result of cooler than average waters across the equatorial Pacific in association with a La Niña, and continuing higher than average temperatures in the central to southeastern Indian Ocean.
The chances of exceeding the median rainfall over February to April are generally between 45 and 55% over nearly all of NSW, Victoria, Tasmania and South Australia (see map). So the chances of being wetter than normal are about the same as the chances of 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 in parts of southern and far northwest NSW, and also in the far west of SA. In most places though, the effect is only weakly or very weakly consistent; the main reason for the near 50:50 odds (see background information).
A La Niña event is in progress across the Pacific Basin and computer models indicate it will persist at least until autumn. The 30-day value of the Southern Oscillation Index (SOI) was +18 as at 21st January. 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, NSW, SA, Victoria and Tasmania at the following numbers:
THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 26th February 2008