Australia has this week sweltered through four of its 10 hottest days on record, with the mercury edging close to 50 degrees.
The Bureau of Meteorology said the heatwave was expected to peak in New South Wales on Friday.
Maximum temperatures in most of the state are expected to stay above 41 degrees until then, something not seen in 80 years.
Penrith is forecast to reach 45 degrees on Friday, with the city to hit 34. Temperatures of up to 47 degrees are expected to continue inland.
Meanwhile, 16 people presented at South Australian emergency departments with heat-related conditions in the 24 hours to Wednesday afternoon. Seven people were admitted for further treatment.
More admissions were expected, with authorities warning health issues were more likely after several days of sustained hot weather.
White Cliffs in NSW topped 48.2 degrees on Wednesday, its hottest ever, along with Wilcannia on 47.9 degrees.
Tuesday was even warmer in South Australia, when the small town of Tarcoola hit a scorching 49 degrees. Port August reached 48.9.
“They are pretty incredible temperatures,” Bureau of Meteorology senior forecaster Michael Efron said.
But wait, there’s more
SA’s State Emergency Service is maintaining an Extreme Heatwave Emergency Warning and the state government has declared a Code Red during the current conditions.
The Code Red triggers extra funding so services for the homeless can be extended. A special phone line is also operating to provide regular checks on the elderly and others at risk.
Temperatures are expected to ease marginally on Thursday in SA and then cool further throughout the following three days.
Cool relief, however, will be short lived – the heat is expected to return next week with Adelaide forecast to have maximums in the mid-to-high 30s from Monday into the middle of the week.
On Wednesday, the bureau said the past four days had been in Australia’s top 10 hottest on record.
Penrith in Sydney’s west is expected to have five consecutive days above 39 degrees, which last occurred in 2011.
Sydney city is expected to reach 32 degrees on Thursday, followed by 34 on Friday, before temperatures drop to the high 20s from the weekend.
Melbourne escapes the brunt of the blast, with temperatures to remain moderate: 33 on Thursday, 28 on Friday, and 23 on Saturday.
Adelaide is forecast to reach 37 degrees on Thursday, followed by 29 on Friday and 30 on Saturday.
Canberra is expected to reach 41 on Thursday and 40 on Friday, before dropping to the low 30s over the weekend.
Perth is tipped to be a cooler 26 on Thursday, before heading into the 30s on Friday and Saturday, and smashing 40 degrees on Sunday.
Brisbane and Darwin are both expected to remain in the low 30s through the week, while maximum temperatures in Hobart are forecast to sit in the mid-20s.
The past 4 days are in Australia's top 10 warmest days on record—and the trend looks like continuing today. The nights have been warm too, which is what defines #heatwave conditions https://t.co/u6dbfmKPk6 Stay cool, check on loved ones & follow advice from health authorities pic.twitter.com/8Qisw9m4LM
— Bureau of Meteorology, Australia (@BOM_au) January 16, 2019
Heatwave causes fires, health warnings
Thousands of dry lightning strikes have sparked scores of fires across Tasmania, leading to helicopter evacuations of bushwalkers and prompting authorities to seek interstate help to battle the blazes.
A large uncontrolled bushfire in central Tasmania was threatening communities on Wednesday afternoon, where residents have been urged to leave.
Fire weather warnings are in place for NSW and Canberra on Thursday, with total fire bans in multiple areas.
Authorities are reminding people to stay indoors, minimise physical activity and keep hydrated.
People aged over 75 and those with chronic medical conditions, as well as those living alone, are particularly vulnerable.
City air quality is also expected to worsen because of the heat, with high ozone levels forecast.
Pet owners are also reminded to keep their animals indoors if possible on hot days and keep them out of the sun, with good ventilation and plenty of water.