While parts of Queensland and South Australia could see hundreds of millimetres of rain, many southern capitals will likely see severe, even extreme, heatwaves.

Adelaide, Melbourne, Sydney and Canberra are all forecast to swelter through several 40C plus days this week.

First to hit, though, will be the rain and much of Queensland could get a lashing as the monsoon hits home.

The Bureau of Meteorology has issued a severe weather warning for areas around Townsville and Charters Towers stating heavy rain and flash flooding could deluge the region.

Over a six-hour period on Monday the weather bureau has said as much as 200mm of rain could fall on Townsville. That would be around a month’s rain in just a few hours. Similar totals could come down around the south east of the Gulf of Carpentaria on Tuesday.

A wet week in Townsville but showers lessening the closer it gets to the weekend. Temperatures in the low 30s. Drier in Brisbane with just a few spots here and there for the week with temperatures reaching 31-33C.

Also in the north, Darwin is looking at 3-10mm of moisture each day during afternoon storms and high of 33C.

“The rain will continue over the next few days as far south as Mackay,” said Sky News Weather channel meteorologist Rob Sharpe.

“By the middle of next week, the rain shifts westwards with heavy falls in the Northern Territory. Then the low looks to dissipate and merge into a low pressure trough drifting all the way down into South Australia where heavy falls are possible in the west and far south of South Australia, then potentially into Victoria and New South Wales.”

‘BEST RAIN IN YEARS’

Effectively the rain could do a vast spiral, heading west from the Queensland coast, then south, across Victoria and potentially back up to the east coast again.

“There will be some handy rain on the cards for many areas but there will be some pretty remarkable rain for western parts of South Australia where it’s looking like the best rain in years for the Nullarbor and Ceduna,” said Mr Sharpe.

Average January rainfall in Ceduna is a mere 8mm. But Friday and Saturday could see between 8mm and 20mm of moisture on both days.

THE HEAT

As well as the rain, it will be a week of heat.

“It’s very hot in the west at the moment and the heat will slowly drift eastwards and then focus down on the south east,” he said.

“By the time we get to back end of the coming week we’re looking at severe heatwaves likely to hit Melbourne, Adelaide, Canberra, and parts of Sydney.”

The hot weather will engulf the south east ahead of the rain which should bring the temperatures down a notch or two.

It will be a blistering day in Perth today where the heat destined for the east is brewing up nicely. A high of 38C today followed by 33C tomorrow and then highs in the mid-20s for much of the rest of the week.

Adelaide will see 27C today but the mercury is set to soar, hitting 40C on Thursday and Friday, before the rain band comes through on Saturday bringing temperatures down into the mid-20s. Up to around 15mm of moisture could fall on the weekend.

Cooler in Melbourne with a high of 23C today but scorching later this week topping out at 41C on Friday and 36C on Saturday. Storms and showers possible on the weekend as the cold front and rain barrel through.

Much the same cycle in Hobart. A cool 22C today with cloudy skies and then getting warmer each day until it hits 38C on Friday. Downpours on Saturday will then coincide with a temperatures drop.

Spare a though for Canberrans though, who are set to sweat through a week of unremitting heat. A high of 36C today will set the tone but there will be a jump to 40C on Friday and 41C on Saturday. The heat will lessen on Sunday, but not by much and only into the late-30s.

There might be some splashes of rain on Sunday in the capital.

Sydney will see a heat spike but will be see more manageable days beforehand. Highs in the mid to late-20s for much of the week then a jump to 35C on Saturday and 37C on Sunday. Far warmer in the city’s west, however. Expect every day to be north of 30C in Penrith with a high of 43C on Saturday.

The BOM is forecasting a heatwave for much of the country’s south east with extreme conditions around Canberra, south eastern NSW and eastern Tasmania later this week.