National temperature outlook

Issued 24 April 2014

Warmer overnight temperatures more likely for southern Australia

Text details of chance of warmer maximum and minimum temperatures

Summary

  • Warmer days are more likely over the southwest coast of WA, southern Victoria, and Tasmania, with parts of the WA interior more likely to have cooler than normal daytime temperatures
  • The chances of warmer or cooler days are roughly equal over the majority of Australia
  • Warmer nights are more likely over most of southern Australia and the Kimberley in WA
  • Climate influences include a warming tropical Pacific, and a warm Indian Ocean
  • Outlook accuracy for maximum temperatures is moderate to high over Australia
  • Minimum temperature accuracy is moderate over most of the country, except for parts of the eastern mainland, where accuracy is low.
Probability of exceeding median maximum temperature, large image Probability of exceeding median minimum temperature, large image

Details

The May to July maximum temperature outlook shows a greater than 60% chance of experiencing warmer than normal daytime temperatures over the southwest coast of WA, southern Victoria, and Tasmania. So for every ten May to July outlooks with similar odds to these, about six to eight of them would be warmer than average over these areas, while about two to four would be cooler.

Conversely, over parts of the WA interior, the chances of warmer than normal daytime temperatures are less than 40%. In other words, the chances of cooler than normal daytime temperatures are greater than 60%.

Over most of Australia the chances of warmer or cooler daytime temperatures are roughly equal.

The chances that the average minimum temperature for May to July will exceed the long-term median are greater than 60% over southern Australia, and over most of the Kimberley in WA (see map).

The chances of receiving cooler or warmer than normal night-time temperatures for May to July is roughly equal (i.e., close to 50%) over the remainder of the country.

Climate influences

The El Niño-Southern Oscillation (ENSO) currently remains neutral, but is in a state of transition towards El Niño. Dynamical models surveyed by the Bureau indicate that further warming of the tropical Pacific is likely in the coming months, with models approaching or exceeding El Niño thresholds during the southern winter.

Sea surface temperatures in the eastern Indian Ocean, to the south of Australia, and in parts of the Tasman Sea are currently warmer than normal, and are generally expected to remain warm through the forecast period. Typically during El Niño, daytime temperatures are expected to be warmer than normal during the second half of the year. It is possible that the warm eastern Indian Ocean may be somewhat negating the effect of the developing El Niño on likely daytime temperatures.

The Indian Ocean Dipole (IOD) is expected to remain neutral for the next three months, and is therefore unlikely to have a significant influence upon this outlook.

How accurate is the outlook?

Maximum temperature outlook accuracy for the May to July period is:

  • High over northern and eastern Australia, and parts of western WA, and
  • Moderate over most of WA, the southern NT, SA and western NSW

Minimum temperature outlook accuracy for the May to July period is:

  • Moderate over most of WA, the NT, SA, most of Queensland, central NSW, southern Victoria, and Tasmania, and
  • Low over southeast SA, northwest Victoria, parts of southern Queensland, and most of NSW