Southeast Australian temperature outlook

Issued 18 December 2013

Warmer season more likely for north and east NSW, cooler for southern Victoria and northern Tasmania

Text details of chance of warmer maximum and minimum temperatures

Summary

  • Warmer days and nights are more likely over northern and eastern NSW, and far northern SA
  • Cooler temperatures, especially nights, are more likely in southern Victoria, northern Tasmania and southeastern SA
  • Climate influences include a neutral tropical Pacific, and a warm Indian Ocean
  • Outlook accuracy is moderate for most of southeastern Australia; see accuracy tab for more detail.
Probability of exceeding median maximum temperature, larger view Probability of exceeding median minimum temperature, larger view

Details

The chances of the January to March maximum temperature exceeding the long-term median maximum temperature are greater than 60% over northern and eastern NSW and far northern SA (see map), reaching 75% in the far northeast of NSW. This means that for every ten January to March outlooks with similar odds to these, about six or seven of them would be expected to be warmer than average over these areas, while about three or four years would be cooler.

Conversely, the chance of exceeding the median maximum temperature is less than 40% over southwest coast of Victoria and northern Tasmania. So the chance of a cool season in these areas is about 60%.

The pattern for average minimum temperatures is similar, except there is a slightly higher chance of cool overnight temperatures in southeastern SA, southern Victoria and northern Tasmania. The chances of receiving a cooler or warmer than normal January to March are roughly equal over northern Victoria, most of SA and southwestern NSW.

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 ENSO-neutral conditions are likely to persist at least for the austral summer and early autumn. This means there is no strong shift in the odds from the tropical Pacific in this outlook.

Although the Indian Ocean Dipole has limited impact upon Australia during the months from December to April, the broad area of warmer than average sea surface temperatures across the central Indian Ocean has been shown to influence the climate over large parts of Australia at this time of year.

Lower surface pressures are likely to bring cooler and potentially wetter conditions to parts of southern Australia (such as Tasmania and parts of southwest WA) early in the outlook period.

How accurate is the outlook?

Maximum temperature outlook accuracy for the January to March period is:

  • Moderate over most of NSW and SA, northern Victoria and southern Tasmania
  • Weak over northwest NSW, southern SA, southern Victoria and northern Tasmania

Minimum temperature outlook accuracy for the January to March period is:

  • Moderate over Tasmania, most of NSW, and patches of southern SA and Victoria
  • Weak over most of Victoria and SA