Western Australian temperature outlook

Issued 24 April 2014

Warmer overnight temperatures more likely for southern WA

Text details of chance of warmer maximum and minimum temperatures

Summary

  • Warmer days are more likely over the southwest coast of WA
  • Warmer nights are more likely over southern and far north of WA
  • Climate influences include a warming tropical Pacific, and a warm Indian Ocean
  • Outlook accuracies for maximum and minimum temperatures are moderate to high over most of WA
Probability of exceeding median maximum temperature, larger view Probability of exceeding median minimum temperature, larger view

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. 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, parts of the inland Pilbara and northern Goldfields, the chance of warmer than normal daytime temperatures is less than 40%. In other words, the chance of cooler than normal daytime temperatures is greater than 60%.

For the rest of WA, 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 much of the southern and far north WA (see map).

The chance 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 State.

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 most 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.

How accurate is the outlook?

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

  • Moderate to high over most of WA

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

  • Moderate to high over most of WA