Australian weather forecast: Jane Bunn looks at rain set to drench Queensland while Melbourne and Adelaide swelter

Rain is likely to affect areas from Mackay through to Cairns in a weather pattern that brings rain day after day, while southeastern Australia endures a lengthy spell of extreme heat from this weekend.

Significant rain

Low pressure is developing off northeast Queensland that should persist for the rest of the week and across the weekend.

This is the perfect position to let a huge feed of moisture from the tropical Pacific Ocean be turned into rain, and with the pattern persisting for such a long time, the rainfall totals will be significant, with a big impact for those living and working in the area.

The low may intensify on the weekend, increasing the intensity of the rain, and the pattern could linger into next week as well. Over the course of the next week, a large part of the northern Queensland coast is likely to see more than 300mm.

Within this activity there are always locally heavier falls - that could top out over 400mm.

Significant heat

Meanwhile, extreme heat is set to return to southeastern Australia.

The run of milder days comes to an end at the end of the week. Temperatures rise over the weekend, turning extreme from Sunday.

The last spike of heat lasted for just one day, but this one is shaping up to be a lengthy hot spell. A heatwave with several days in a row of considerably above average days and nights.

Most parts of southeastern Australia, including Adelaide and Melbourne, will be near 40C for several days in a row.