Northwestern Australia has just begun an oppressive six-day heatwave that will see temperatures reaching 46 degrees for several consecutive days in some areas.

A high pressure ridge passing to the south of Australia is allowing a heat trough to develop over the country's western tropics this week.

This broad area of low pressure will cause a stagnant pool of hot air to build up across parts of WA and the NT, allowing temperatures to soar.

Image: Forecast surface air temperature on Saturday afternoon, according to the ECMWF-HRES model.

The notoriously hot town of Marble Bar is likely to be one of the hottest places in the country over the coming days. After reaching 45.6°C on Wednesday, the town is forecast by the Bureau of Meteorology to reach 45°C on Thursday and 46°C every day between Friday and Monday.

While these temperatures may come as a shock to many Australians, they are not uncommon in Marble Bar at this time of year. The town's average maximum temperature in December is around 42°C and its record for the month is 49.3°C from 2018.

However, this heatwave will be a decent one, even by local standards. The temperature could get above 45.5°C for six days in a row, which would be a feat that has only happened during December on three occasions during the last two decades.

Increasing cloud and thunderstorm activity will help break down some of the heat in northern Australia early next week. Temperatures should return closer to average in Marble Bar from about Tuesday.