'Like a furnace': Massive heatwave could roast Australian records

Almost all of mainland Australia will be roasted in a huge heatwave next week, with the mercury likely to nudge 50 degrees in parts of the south.

Perth is in the midst of a four-day scorching as it plays host to the first day-night cricket Test between Australia and New Zealand.

Maximum temperatures are likely to near or exceed 40 degrees until Sunday, with the heat gradually shifting east.

Records are likely to tumble in many areas for days of consecutive heat even if individual daily maximums are broken, Kim Westcott, a meteorologist with Weatherzone, said. Remaining moisture in the environment may not fare well.

"Days when it feels like a furnace outside are not going to be great for any moisture that's still around," she said.

Apart from humans caught in the prolonged heat, wildlife from birds to bees, livestock and pets may also struggle.

Heat records may tumble in the coming week as a huge dome of heat builds over inland Australia.Credit: Alex Ellinghausen

On present forecasts, the hottest places may be in South Australia, with the Bureau of Meteorology indicating back-to-back days of 49 and 50 degrees in some remote regions for next Wednesday and Thursday.

Ms Westcott said a "very weak pressure pattern" meant the heat has been able to build over the inland with little disturbance from cold fronts. The system will drift slowly eastwards next week.

Diana Eadie, a bureau forecaster, said the late arrival of the monsoon over northern Australia had also contributed to the build-up of the "very warm air mass" that would start to circulate southwards.

Much of the country's south will exceed 45 degrees by midweek, or 12-16 degrees above the December average, she said.

Melbourne and Sydney will most likely be spared the worst because of sea breezes, but inland suburbs might still swelter.

The Victorian capital can expect maximums in the low to mid-30s for three days from Tuesday, with 41 degrees forecast for Friday.

In Sydney, updated forecasts have the city reaching 33 degrees on Thursday while western suburbs such as Penrith could reach 44 degrees, the bureau said.

The harbour city this week topped 30 degrees for the 32nd time this year, beating the previous record of 31 such days set back in 1922.

Other hotspots include a trio of days of 40 degrees for Adelaide and two in a row for Canberra.

The hottest December day was marked in Birdsville, Queensland, on Christmas Eve, 1972, with a 49.5 degree reading.

Two of Australia's only three reliably measured temperatures above 50 degrees were recorded at Oodnadatta in South Australia, with 50.7 on January 2, 1960, and 50.3 the following day. Mardie in the WA's Pilbara hit 50.5 degrees on February 19, 1998.

Oodnadatta is forecast to reach 46-47 degrees for the three days from Tuesday, while Mardie is already in the midst of at least eight days at least 40 degrees.

Given the intense heat, Australia could challenge for its hottest day on record on a couple of the days next week.

The start of 2013 was the hottest on record for the country, with average daytime temperatures reaching 40.3 and then 40.1 on January 7 and 8 that year, respectively. Those days remain the only two days with average maximums above 40 degrees, according to bureau data.

"There is the potential we could approach or exceed that [40.3-degree average] as we head towards the latter part of next week," Ms Eadie said.

Even a reading of 37.8 degrees would be enough to give Australia an average of 100 degrees fahrenheit for the day.