A strong surge of autumn heat will track its way across the country in the second half of this week and into the early part of next week, with low and medium intensity heatwaves already predicted by the BoM on Tuesday.

Take a look at the map below. It shows a large pool of very hot early autumn air extending from WA's Pilbara region all the way down to the coastline of western South Australia.

In those areas, maximum temperatures in excess of 44°C can be expected, as represented by the pink zone in the image above. That heat will then drift eastwards, with NSW in the bullseye.

While extreme temps above 40°C will be confined to the far west of that state, maximums in the mid-to-high-thirties will be widespread and extend all the way to the coast, with temps nearing 40°C in western Sydney on both Thursday and Saturday.

Prolonged heat will affect much of Australia this week, despite the autumn equinox being only days away. pic.twitter.com/JYqbRdiUsQ

— Andrew Miskelly (@andrewmiskelly) March 13, 2023

It's not just the unseasonably hot temperatures a few days before the autumn equinox that is newsworthy here. The prolonged nature of the coming hot spell is quite remarkable. For example:

• Bourke in the NSW Upper Western forecast district can expect a run of maximums of 40°C, 40°C, 41°C, 40°C and 39°C from Thursday through till Monday. Its average March max is 32.6°C, and it's worth noting that four consecutive days of 40°C or higher have never occured this late in 150 years of records
• Dubbo in central NSW can expect a run of maximus of 36°C, 35°C, 37°C, 37°C and 37°C from Thursday through till Monday. Its average March max is 29°C
• Penrith in western Sydney can expect a run of maximums of 38°C, 34°C, 38°C, 37°C and 35°C from Thursday through till Monday. Its average March max is 27.5°C

Meanwhile Sydney can also expect a run of four straight days with a maximum of 30°C or higher from Thursday through to Saturday, with a max of 35°C on Thursday.

Remember, it was only on February 21 that Australia's largest city ended a near-record run of 331 days between 30-degree temperatures.

We'll keep you posted with the latest on this impending heatwave in coming days.