An extreme heatwave is baking parts of northern Australia this week, with the Western Australia town of Fitzroy Crossing registering the country’s first 45°C so far this spring.

A slow-moving upper-level high pressure system has allowed a very hot air mass to build over northwestern Australia this week.

On Monday, the temperature peaked at 43.6°C at Telfer in the far eastern Pilbara district of WA. The mercury then rose even higher on Tuesday, reaching as high as 45.1°C at Fitzroy Crossing in the Kimberley region. This was Australia’s first 45°C in nine months.

Temperatures are forecast to reach the mid-forties over some northern parts of WA again on Wednesday, Thursday and Friday. Over this three-day period, minimum temperatures will also stay up around 30°C for some places.

While this heat is not breaking records, it is part of a prolonged run of days and nights that will be hot enough to be classified as an extreme heatwave.

Image: Heatwave forecast for the three days ending on Thursday this week. Source: Bureau of Meteorology.

Some computer models predict that maximum temperatures could reach around 47°C in the Pilbara over the next few days. Marble Bar is one location forecast to see daily highs around 46°C on Thursday and Friday.

At this stage, temperatures should start to back off towards the end of the week as building tropical moisture causes an increase in cloud, rain and thunderstorm activity over northern WA