National temperature outlook
Issued 18 December 2013
The chances of the January to March maximum temperature exceeding the long-term median maximum temperature are greater than 60% over the northeastern half of the country (see map). Odds increase to greater than 70% over the Top End of the NT, central and southern Queensland, and parts of the NSW coast. So for every ten January to March outlooks with similar odds to these, about six or seven of them would be expected to be warmer than average over these areas, while about three or four years would be cooler.
Conversely, the chances of exceeding the median maximum temperature is less than 40% over southwest WA, the southwest coast of Victoria and northern Tasmania. The chances of receiving a cooler or warmer than normal January to March is roughly equal (i.e., close to 50%) over the remainder of the country.
The chances that the average minimum temperature for January to March will exceed the long-term median are greater than 60% over the Kimberley in WA, the NT, Queensland, and northeast NSW. Odds increase to greater than 70% over the northern Kimberley and the Top End of the NT, parts of central and southern Queensland, and the far northeast of NSW.
The chances of exceeding the median minimum temperature is less than 40% over the far southeast of SA, southern Victoria and northern Tasmania. In other words, the chances of cooler than normal night-time temperatures is greater than 60%.
The El Niño-Southern Oscillation (ENSO) remains neutral, with the majority of atmospheric and oceanic indicators close to their long-term average. Dynamical models surveyed by the Bureau suggest ENSO-neutral conditions are likely to persist at least for the austral summer and early autumn. This means there is no strong shift in the odds from the tropical Pacific in this outlook.
Although the Indian Ocean Dipole has limited impact upon Australia during the months from December to April, the broad area of warmer than average sea surface temperatures across the central Indian Ocean has been shown to influence the climate over large parts of Australia at this time of year.
Lower surface pressures are likely to bring cooler and potentially wetter conditions to parts of southern Australia (such as Tasmania and parts of southwest WA) early in the outlook period. For northern regions, tropical Australian sea surface temperatures are currently average to slightly cooler than average, and are expected to remain that way over the forecast period. Weak to moderate tropical activity (cloud and rainfall associated with the Madden-Julian Oscillation) is expected in the first month.
How accurate is the outlook?
Maximum temperature outlook accuracy for the January to March period is:
- Moderate over most of Australia (with exceptions listed below)
- Weak over southern parts of the Australian mainland, central parts of the NT, northeast SA, northwest NSW and the Lower Carpentaria region of Queensland
Minimum temperature outlook accuracy for the January to March period is:
- Moderate over the northern half of WA, northern and western parts of the NT, southern and eastern Queensland, eastern SA, NSW, parts of Victoria and Tasmania.
- Weak through the much of the southern half of WA, western and southeastern parts of SA, western Queensland and through central parts of the NT
- Very weak in parts of western and southern WA and the Lower Carpentaria region of Queensland