Australia, Prepare To Get Sweaty: Extreme Heat On The Way

Here it comes.

The country's eastern capitals will flirt with summer this week as temperatures in Sydney, Melbourne, Adelaide, Canberra and Brisbane make their way into the mid-30s and possibly higher.

The mercury will begin to rise on Wednesday as a high pressure system in the Tasman Sea and trough of low pressure in western parts of Australia push hot air across the country.

"Those two systems combined will cause northerly airflow that will push hot air from inland and northern Australia down towards south-eastern parts of the country," Ten News weather expert Josh Holt told ten daily.

Temperatures in Adelaide and Melbourne are expected to peak on Thursday at 36 and 33 degrees respectively, while Canberra begins a three-day run in the thirties on Wednesday. At 31, it will be the capital's first day above 30 degrees in six months, before reaching 33 on Thursday and Friday.

The heat will really set in for NSW on Friday, with potential heatwave conditions. Sydney is forecast to reach 37, its warmest day since Februrary.

"Most of NSW central and western areas will see temperatures of 38-39 but certainly pushing 40 degrees in some areas," Holt said.

"If we hit 37 degrees on Friday for Sydney, that will be 13 degrees above average."

With areas in the city's west expected to sit around the 40 degree mark over Thursday and Friday, warnings were issued on Wednesday for those vulnerable to heat exhaustion.

“It’s important that people are alert to the symptoms associated with heat exhaustion in themselves or others, especially young children and the elderly,” NSW Ambulance Chief Superintendent Alan Morrison said in a statement.

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"Heat can kill which is why it's so important to stay hydrated and look out for the elderly, the young and pets."

Between December 1 2017 and March 31 2018, paramedics treated 4451 patients for dehydration and responded to 227 people suffering heat exhaustion.

The good news is temperatures will begin to fall back down into the twenties as we head into the weekend.

"It’ll come in the form of a cold front, so the temperatures will drop dramatically from their peaks over 24 hours and they’ll probably drop by about 10 degrees," Holt explained.

"So for Adelaide and Melbourne they’ll see their hottest temperatures Thursday dropping down on Friday-Saturday. For Sydney we’ll see the hottest temperatures Friday dropping down on Saturday."

While the cool air rolls into the south-easterly areas of the country, Brisbane temperatures will only begin to head into the thirties on Saturday with an expected peak of 32 degrees. The city will sit in the high twenties throughout the week before that.