Australia’s southeast coast is set to swelter through a couple of gruelling days as temperatures soar across Victoria, South Australia and Tasmania.

After two weeks of brutal heat, Sydneysiders will receive somewhat of a reprieve with a looming cold front coming through on Sunday.

But for those further down the coast, authorities are warning that the conditions could prove fatal.

View photos In addition to the brutal heat, a severe weather warning for damaging winds has also been issued for parts of the southeast coast. Image: Weatherzone More

“There will be scores of people who have cardiac arrest or who present in a really severe state by ambulance,” Victoria’s acting Chief Health Officer Brett Sutton said.

Meanwhile parents are again being told not to leave children in the car on hot days, as they could be unconscious in minutes.

Victoria: ‘If a fire starts it’s going to be uncontrollable’

Victorians are set to bake and firefighters are on high alert with thunderstorms, strong winds and fire risks adding to the potentially deadly conditions.

Mildura, Swan Hill, Kerang and Echuca in the state’s northwest, are tipped to hit 46C while Bendigo heads to a top of 45C and Melbourne is forecast to reach 42C on Friday.

A cool change will bring welcome relief for some areas later in the day but may bring wind gusts up to 100km/h with the potential to exacerbate fires.

View photos Melbourne’s Brighton Beach is expected to get a workout before the temperatures drop away later in the day. Image: AP More

Here's how your day looks in #Melbourne tomorrow. After an early morning low of 19 degrees around 4am expect a top of 42 degrees near 4pm. A squally cool change will rapidly drop temperatures just after that. Full forecast details: https://t.co/kp54lP875S pic.twitter.com/xzAozzwEqx — Bureau of Meteorology, Victoria (@BOM_Vic) January 3, 2019





Thunderstorms are also expected in parts of central and eastern Victoria in the late afternoon, with the possibility of dry lightning strikes posing a risk of fire.

A total fire ban has been issued for Victoria with extreme fire warnings for the Mallee and the Wimmera.

“If a fire starts it’s going to be uncontrollable, it’s going to be fast-moving,” Emergency Management Commissioner Andrew Crisp said.

SA swelters through a scorcher

View photos Adelaidians are set to flock to the beaches over the next couple of days to escape the soaring mercury. Image: AAP More

South Australia has sweltered through a summer scorcher with temperatures in the west and northern parts of the state soaring into the mid-40s.

Ceduna, on the state’s west coast, was among the hottest spots with the mercury reaching 47.1C on Thursday.

Other centres were almost as hot including Oodnadatta with 46.3C, Nullarbor with 46.2C and Port Augusta with 45.5C.

Another very hot day for #SA tomorrow with a return to high 30's/low 40's for Ag areas and mid 40's inland 🥵. Temps staying high overnight before a change moves through central districts Friday morning and eastern districts during Friday arvo bringing temps back down. pic.twitter.com/i7t7rDsDqg — Bureau of Meteorology, South Australia (@BOM_SA) January 2, 2019





In Adelaide the top at the Kent Town observation centre hit 42.3C.

But the Bureau of Meteorology said a cool change was slowly edging across SA and dropped the temperature by 10 degrees at Nullarbor in just eight minutes.

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