Warmer days and nights are more likely than not for Australia for July to September. The Bureau of Meteorology in its latest national temperature outlook puts the chances that the July to September maximum temperature outlook will exceed the median maximum temperature at greater than 60% over Australia. Chances are greater than 80% over southwest WA, southeast Queensland, northeast NSW, southern Victoria and Tasmania. So for every ten July to September outlooks with similar odds to these, says the Bureau, about six to eight of them would be warmer than average over these areas, 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 also are greater than 60% over Australia. Chances rise to greater than 80% over southern and central WA, southern Victoria, Tasmania, and the eastern seaboard of NSW (see map above).
The Bureau’s outlook says the 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.
On the outlook for rainfall the BOM believes a drier than normal season is more likely for parts of central and eastern Australia with a wetter than normal season is more likely for eastern Tasmania