Northern Australian rainfall outlook

Issued 25 June 2014

Drier than normal season likely for parts of northern Australia

Summary

  • A drier than normal season is more likely for parts of central and eastern Australia
  • Climate influences include warm Indian and Pacific oceans
  • Outlook accuracy is moderate over most of northern Australia. See accuracy tab for more information.
Probability of exceeding median rainfall, large image

Details

The chances of receiving above median rainfall for July to September are less than 40% over parts of the southern NT and the southern two-thirds of Queensland. In other words, this means the chances of below average rainfall is greater than 60% in these areas. For every ten July to September 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.

Across the Top End and Cape York there is no significant shift in the odds towards either a wetter or drier than normal season. It should be noted that northern Australia is presently in its dry season. This means that average rainfall at this time of year is far less than is received during other parts of the year for most of northern Australia, except eastern Queensland (see Rainfall averages tab).

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 drier signal across the country due to patterns in the ocean and atmosphere across the Pacific. This drier signal is 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?

Outlook accuracy for the July to September period is:

  • Moderate over eastern parts of the NT and most of Queensland
  • Low to very low over the western and southern NT and Cape York