A HEATWAVE is sweeping across parts of Australia with temperatures set to top 40C, but the rain-bringing La Nina event bodes for a cooler 2018 in most areas.
The low intensity heatwave is predicted to engulf Brisbane, northeast and central Queensland, parts of NSW, Tasmania and inland parts of Western Australia this week.
In Western Australia, the conditions will peak to extreme in the Pilbara district just south of Exmouth from Thursday to Saturday.
In NSW, a low-intensity heatwave will grip Sydney and large parts of the state between Thursday and Sunday.
But once the heatwave subsides, over the next three months most of Western Australia, southwest South Australia, northern Tasmania, eastern Victoria, NSW and southern Queensland will be wetter and cooler than average thanks to a La Nina event.
The Bureau of Meteorology (BOM) has issued the La Nina alert, saying there is three times the normal chance of the event which generally brings above average rainfall.
The tropical Pacific Ocean is showing a typical La Nina pattern, but ocean temperatures will stay cooler than average so it is less likely to drive widespread rain.
BOM senior hydrologist Dr Paul Feikema said: "While La Nina looks likely during summer, it's expected to be short-lived and have less effect on rainfall and temperatures than recent La Nina events."
The 2010 to 2012 La Nina brought significant rain to large parts of the country.
Although that is unlikely, temperatures will be cooler in the last two months of summer compared with the scorching start to 2017.
The only areas likely to remain warmer than average are far southwestern and southeastern Australia, including Tasmania.
Hot spots with above-average daytime temperatures especially in January will stretch from eastern Victoria to South Australia, just shy of Adelaide.
The BOM summarised the final three months of 2017's weather by saying parts of Australia had lived through both very hot and very wet conditions.
"There were late spring rains in parts of South Australia and Western Australia and in
some parts of southeastern Australia there was heavy rain," BOM senior climatologist Dr Andrew Watkins said.
"Parts of Victoria and NSW had two to three times their usual rainfall in a few days," he said.
"Summer heat started early in parts of southeastern Australia."
Tasmania's average maximum temperature for November was nearly four degrees above normal, making it warmer than their usual January temperatures with six consecutive days over 26C.
And Melbourne endured nine consecutive days over 28C.
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