Western Australian temperature outlook

Issued 25 June 2014

A warmer season likely for Western Australia

Text details of chance of warmer maximum and minimum temperatures

Summary

  • Warmer days and nights more likely for WA for July to September
  • Climate influences include warm Indian and Pacific oceans
  • Outlook accuracy for maximum temperatures is moderate to high over most of WA, except for parts of southwest WA, where accuracy is low.
  • Minimum temperature accuracy is patchy for July to September, with generally moderate accuracy over the eastern parts of WA, and low accuracy for the rest of WA
Probability of exceeding median maximum temperature, larger view Probability of exceeding median minimum temperature, larger view

Details

The chances that the July to September maximum temperature outlook will exceed the median maximum temperature are greater than 60% across WA, rising to above 80% over southwest WA. For every ten July to September outlooks with similar odds to these, about six to eight of them would be warmer than average across WA, while about two to four would be cooler.

The chances that the average minimum temperature for July to September 2014 will exceed the long-term median are greater than 60% across WA, rising to above 80% over southern and central WA (see map).

Climate influences

Warming of the tropical Pacific Ocean over the past several months has primed the climate system for an El Niño in 2014. However, in the absence of the necessary atmospheric response, the increase in Pacific Ocean temperatures has levelled off in recent weeks. Despite some easing in the model outlooks, international climate models surveyed by the Bureau still indicate El Niño is likely to develop by spring 2014. While POAMA, the model that produces the seasonal outlooks, does not forecast a high probability of El Niño, it retains a warmer signal across the country due to patterns in the ocean and atmosphere across the Pacific. This warmer signal is generally consistent between international models regardless of their ENSO forecast.

Models indicate the currently warm Indian Ocean is likely to remain warm. 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 July to September period is:

  • Moderate to high over most of WA
  • Low over parts of southwest WA

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

  • Moderate over eastern parts of WA
  • Low for the rest of WA (see map)