Warmer than normal waters in the Indian Ocean have prompted the Bureau of Meteorology to revise its forecast in favour of wetter than average conditions for much of eastern and northern Australia over the next three months.

However the forecast is less optimistic for southern Australia, with a drier than normal season predicted for May to July in Tasmania, most of Victoria and south eastern South Australia.

In its latest three-monthly season climate outlook released today, the Bureau says the outlook is predominately a result of warmer than normal waters in the Indian Ocean. Temperatures in the tropical Pacific Ocean remain near normal and had a minimal impact on the latest forecast.

The outlook suggests that the chances of receiving above median rainfall during the May to July period are between 60 and 80pc across most the NT, far northeast WA, the southern half of Queensland and northern NSW.

Odds increase to 70 to 80pc over much of southeast Queensland and northeast NSW.

Such odds mean that for every 10 years with similar ocean patterns to those currently observed, about six to eight years would be expected to be wetter than average over these areas, while about two to four would be drier.

In contrast, the chances of receiving above normal rainfall are between 30 and 40pc across most of Victoria, southeastern parts SA and Tasmania.

In other words, the chances of below normal rainfall range from 60 to 70pc.

Over the rest of the country, the chances or above or below average rainfall are roughly equal.

The tropical Pacific remains neutral with respect to ENSO (El Niño-Southern Oscillation). While it is known that predictions from dynamical models during the April through June period have lower skill, all climate models surveyed by the Bureau of Meteorology indicate sea surface temperatures in the tropical Pacific Ocean are likely to remain within neutral thresholds for the next season.

Meanwhile, the national temperature outlook for May to July shows that warmer days are more likely over most of southern Australia, cooler days are favoured over southeast Queensland and the border region between WA and southwest NT, and warmer nights are more likely over northeastern and southwestern Australia.

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