National rainfall outlook

Issued 24 February 2014

Drier autumn more likely for parts of Queensland, while wetter favoured in the west

Text commentary of chance of increased rainfall

Summary

  • A drier than normal autumn is more likely for areas of Queensland and southeastern Northern Territory
  • A wetter than normal autumn is more likely for southern and western parts of WA
  • Outlook accuracy is moderate to high over much of eastern and central Australia, except for some areas near the WA/NT border, southern parts of SA and western parts of WA where the accuracy is low.
Probability of exceeding median rainfall, large image

Details

The chances of exceeding the median rainfall during autumn are less than 40% over parts of central and western Queensland and the southeast corner of the NT. In other words, the chances of below average rainfall are at least 60% over these areas. For every ten autumn outlooks with similar odds to these, about three or four of them would result in above-average rainfall over these areas, while about six or seven would be below average.

Conversely, the chance of exceeding the median rainfall is greater than 60% over the western half of WA, and a small area in northeast of the NT.

Over the rest of the country, there is no significant shift in the odds towards either a wetter or drier than normal autumn.

Climate influences

The El Niño-Southern Oscillation (ENSO) remains neutral, with the majority of atmospheric and oceanic indicators close to their long-term average. Dynamical models surveyed by the Bureau suggest that while ENSO-neutral conditions are likely to persist through autumn, some warming of the central Pacific Ocean is likely. While short of El Niño levels, this warming may still have some impacts upon Australian climate

Ocean temperatures surrounding Australia are generally expected to remain close to their 1981-2010 average, though some cooler than average temperatures around northern and north-eastern coasts early in the season may mean a reduction in evaporation in those areas. Atmospheric pressures may be below average over some southern areas in the first half of the season, which may favour drier westerly winds over some parts of eastern Australia.

The Indian Ocean Dipole is typically too weak to have a significant influence on the Australian climate during the autumn period.

How accurate is the outlook?

Outlook accuracy for the autumn period is:

  • Moderate over most of eastern and central parts of contintent, including the Top End of the NT, large areas of Queensland, northern and southeastern parts of NSW, western Victoria and Tasmania
  • Low over most of the western and interior parts of WA, west-central parts of the NT, southern coastal areas of SA and most of western Tasmania
  • Very low over an area near the northern parts of the WA-NT border, southwest coastal regions of SA and small areas of inland and southern coastal WA