Australia weather forecast: dangerous bushfire and heatwave conditions to return after brief cool reprieve

Graham Readfearn
Photograph: Sean Davey/AFP via Getty Images

Firefighters and communities devastated by an unprecedented bushfire season can expect a brief reprieve from severe weather conditions before a return of the heat on Friday, the Bureau of Meteorology has said.

Forecasters predict very hot and windy conditions for South Australia on Friday and dangerous bushfire conditions for eastern Victoria and New South Wales on Saturday, with temperatures again reaching into the mid-40s.

“We are assuming that on Saturday weather conditions will be at least as bad as what they were yesterday,” Premier Gladys Berejiklian said. “That is something all of us have to brace ourselves for.”

Related: Climate patterns behind Australia's bushfires, heat and drought set to improve

Patchy showers and thunderstorms are expected with a cold front through Western Australia on Saturday, moving across into Victoria and South Australia on Sunday, reaching NSW late on Sunday or early Monday.

But Jonathan How, a forecaster at the bureau, told Guardian Australia it was uncertain if any significant rain would reach bushfire areas.

He said: “We could see some widespread showers and thunderstorms through the south-east of the country, but it’s going to be patchy and it’s uncertain whether it gets to those fire sites.”

How said Wednesday was much cooler across the south-east after a run of hot days, bringing brief relief for Tasmania, Victoria and NSW.

“From tomorrow, we start to see the heat build again from southern parts of WA and South Australia.

“Friday is a very hot day across South Australia and Victoria with Adelaide getting up to 42C on Friday. Inland Victoria and South Australia will be getting into the mid-40s.”

He said South Australia would experience “elevated fire dangers” on Friday, with forecast high temperatures including 45C for Renmark and 46C for Port Augusta. Mildura in Victoria could reach 44C.

Saturday was already shaping up to be a day of high fire risk for eastern Victoria and New South Wales with temperatures in the high 30s and early 40s across areas that are currently burning.

“That is going to push up fire dangers in Gippsland and southern parts of New South Wales,” How said.

Canberra may reach 42C on Saturday, with temperatures in the western suburbs of Sydney forecast to rise as high as 45C.

The best chance of rainfall over the next week could come on Sunday, with lower temperatures and patchy showers and thunderstorms moving from South Australia and into northern parts of Victoria and southern NSW.

In the north and north-west of the country, there could be more significant rain as a monsoon trough moves south over the next two days, that will be “good news for those in the Top End,” How said.

Forecasters were also watching for a possible tropical low developing in waters south of Indonesia towards the end of this week and early next week.