Increased rainfall odds for most of Australia

National Seasonal Rainfall Outlook: probabilities for November 2010 to January 2011, issued 26th October 2010

Increased rainfall odds for most of Australia

The national rainfall outlook for the November-January period favours wetter than normal conditions over large parts of Australia, most notably in eastern, northern and southwest Australia.

The pattern of seasonal rainfall odds across Australia is a result of warm conditions in the Indian Ocean, as well as cool conditions in the equatorial Pacific Ocean associated with the current La Niña event.

The chance of exceeding median rainfall for November to January are above 60% over most of Queensland, Northern Territory, NSW and South Australia as well as the Kimberley region of WA (see map). The chances of exceeding median rainfall are also between 60% and 70% in many western parts of WA, but much of this region is normally dry at this time of year. Odds increase to over 70% for the northern half of the NT as well as large parts of eastern Australia. Such odds mean that for every ten years with similar ocean patterns to those currently observed, about seven years would be expected to be wetter than average over these areas, while about three years would be expected to be drier during the January quarter.

For the remainder of Australia, namely large parts of South Australia, southern and western Victoria, eastern WA and all of Tasmania, the outlook is more neutral, with odds of exceeding median rainfall around 55%. This means that the chance of a wetter than average November to January period is about as likely as the chance of below average conditions in these areas.

An expanded set of seasonal rainfall outlook maps and tables, including the probabilities of seasonal rainfall exceeding given totals (e.g. chance of receiving at least 200 mm), is available on the "Water and the Land" (WATL) part of the Bureau's website.

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 over much of NSW, Queensland, NT and parts of Tasmania, but generally weakly consistent elsewhere (see background information).

A La Niña event remains well established in the Pacific Ocean. All of the computer models indicate the central Pacific will remain at levels typical of a La Niña through the remainder of 2010, with the majority suggesting the La Niña event will continue until early 2011. For routine updates and comprehensive discussion on any developments regarding El Niño and La Niña, 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: Agata Imielska on (02) 9296 1539, Elise Chandler on (03) 9669 4748, Andrew Watkins on (03) 9669 4360.

Regional versions of this media release are available: | Northern Aust | Southeastern Aust | WA |

Regional commentary is available from the Climate Services Sections in the Bureau's Regional Offices:

Queensland - (07) 3239 8660 New South Wales - (02) 9296 1555 Victoria - (03) 9669 4949 Tasmania - (03) 6221 2043 South Australia - (08) 8366 2664 Western Australia - (08) 9263 2222 The Northern Territory - (08) 8920 3813

THE NEXT ISSUE OF THE SEASONAL OUTLOOK IS EXPECTED BY 23rd November 2010

Corresponding temperature outlook

September 2010 rainfall in historical perspective

July to September 2010 rainfall in historical perspective

Background Information