THE Bureau of Meterorology's national outlook for total rainfall in January to March favours a drier than normal season through much of Queensland, the northeast half of NSW and southwest WA.
In contrast, above average falls are favoured for southern SA, across parts of Victoria and to northern Tasmania.
The odds have been heavily influenced by the El Niño pattern of higher than average temperatures from the Pacific and Indian Oceans.
There is a 30 per cent and 40pc chance that much of eastern and central Queensland and the northeast half of NSW will experience higher than average rainfall for the March quarter, however, this is not as accurate for inland Queensland and NSW.
There are similar odds in southwest WA, although the January to March period is usually rather dry in that part of the country.
Contrasting this, the chances are between 60pc and 65pc for above average January to March falls from the Eyre Peninsula in SA, to central Victoria and northern Tasmania.
Across the rest of the country, the chances of are between 40pc and 60pc, meaning above average falls are about as equally likely as below average.
Outlook confidence is related to how consistently the Pacific and Indian Oceans affect Australian rainfall.
During the March quarter, history shows the effect to be moderately consistent through eastern parts of NSW and Queensland, large parts of the NT and over much of southern and western WA.
An El Niño event persists across the Pacific Basin, with most leading climate models suggesting tropical ocean temperatures will remain above El Niño thresholds until at least early 2010.
El Niño events are usually (but not always) associated with below normal rainfall in the second half of the year across large parts of southern and inland eastern Australia.
However, the influence from El Niño often weakens in the second half of summer. The SOI is approximately -9 for the 30 days ending 16 December.
Warmer in the north and west; cooler in the southeast
The national outlook for March quarter mean maximum temperatures favours above average values in the west of WA and in a broad region covering much of northern and northeast Australia.
In contrast, cooler than average daytime temperatures are indicated in the southeast of the country.
The pattern of seasonal temperature odds across Australia is due to higher than average temperatures in both the Pacific (El Niño) and Indian Oceans, with the Pacific influence being dominant.
The chance that the average January-March maximum temperature will exceed the long-term median maximum temperature, is between 60pc and 65pc in western WA and between 60pc and 90pc northeast of a line from Derby in northern WA to Sydney.
In contrast, there is a 60pc to 70pc chance of cooler than normal days averaged across the season over Tasmania, Victoria and southern SA.
The average minimum temperature for January to March is favoured to be above the long-term median minimum temperature over much of Australia's northern half.
The chances of increased overnight warmth are between 60pc and 85pc over the northern half of the continent, with the highest probabilities in the far north.
In contrast, a small region covering the western half of Victoria and southeast SA has an increased likelihood of cooler than normal nights.
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