|Southeastern Aust Seasonal Rainfall Outlook: probabilities for November 2007 to January 2008, issued 25th October 2007|
Increased falls for parts of southeastern Australia
For southeastern Australia, the outlook for total rainfall over the late spring to mid-summer period (November to January), shows a moderate shift in the odds favouring above average falls over the northern half of NSW and the far north of SA.
The pattern of seasonal rainfall odds across southeastern Australia is mainly a result of continuing higher than average temperatures over parts of the tropical and sub-tropical Indian Ocean.
The chances of exceeding the median rainfall for the November to January period are between 60 and 70% over northern New South Wales and far northern SA (see map). So for every ten years with ocean patterns like the current, about six or seven November to January periods are expected to be wetter than average in these parts of southeastern Australia, while about three or four are drier.
Over most remaining parts of the southeast, the chances of exceeding the three-month median rainfall are between 45 and 60%, except in southwest Victoria where the probabilities drop to around 40% along the coastal fringe.
Outlook confidence is related to how consistently the Pacific and Indian Oceans affect Australian rainfall. During the November to January period, history shows this effect to be moderately consistent across much of Tasmania and NSW, and in patches across Victoria and far northern SA (see background information).
A late-developing La Niña event is in progress across the Pacific Basin and computer models indicate it will persist at least until the early part of 2008. The 30-day value of the Southern Oscillation Index (SOI) was +1 as at 22nd October. 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 27th NOVEMBER 2007