Up to 50mm of moisture is due to fall on some inland areas this weekend, where 200mm is the annual average. That could be bring flash flooding to some of the driest parts of the continent including the Red Centre which is forecast to see a soaking.

Some of that moisture will make it to the capitals, but the heavy falls may run out of steam before they reach the east coast.

“A big weekend of weather awaits most regions of the country with outback rain, humidity across the south east and tropics and a showery change for the south west,” said Sky News Weather Meteorologist Alison Osborne on Friday.

The focus is on a swirling cut-off low-pressure system that is tracking across the Nullarbor.

“An area like a bullseye is an upper level cold pool that enhances rainfall and thunderstorms at the surface.”

At the same time a humid tropical air mass is working its way down towards the south east from inland areas of Queensland that will bring muggy conditions. Severe weather warnings are already in place for Queensland and South Australia.

On Friday, central South Australia including areas such as Coober Pedy could see severe storms and rain as the system passes through with the possibility of dust storms as well. Alice Springs could also experience a storm.

“Some of Australia’s driest regions see only around 100 to 200mm annually, about half that could fall in just a few hours today,” said Ms Osborne.

“It could be the heaviest falls in a couple of years.”

Into Saturday, that rain band will move east bringing heavy rain to Broken Hill, Mildura and then towards Dubbo, Griffith, Wagga Wagga and Forbes as the weekend progresses.

WEATHER IN THE CAPITALS

On Saturday, Adelaide is likely to see some solid downpours with up to 20mm in the gauge and possible thunderstorms. Temperatures are forecast to top out a 21C. Intermittent showers could continue throughout the weekend and into next week with the mercury fluctuating between 25C on Sunday and 17C on Tuesday with overnight lows just moving into double digits.

Some rain in Melbourne today with heavier showers on Saturday and the chance of a storm. It could be a humid day with highs of 25C. Showers will ease on Sunday but they could come back again on Monday. Minimums in the mid teens.

Mostly dry in Hobart this weekend with highs in the low twenties. Some rain could pass through Tasmania early next week.

Canberra is forecast to get caught up in the rain band as it heads east. Just a scattered shower or two on Saturday but there will be more substantial falls, of up to 10mm, on Sunday. Monday will be potentially wetter still with the chance of a storm. Maximums of 19-23C.

“By the end of the Sunday the system runs out of energy and very little rainfall is expected to make it to the New South Wales coast with those showers backing up against the Great Dividing Range,” said Ms Osborne.

Mostly sunny but with the odd shower here and there for Sydney on the weekend. Temperatures will reach around 23C, and as high as 27C on Monday when a storm could rumble through the city’s west. Lows in the mid-teens.

A shower or two could dampen Brisbane but not much rain will get in the gauge. A maximum of 27C on Sunday which will set the tone for next week’s temperatures.

A sunny Friday in Perth will give way to rain and possible storms on the weekend. More than 10mm of moisture could fall between Saturday and Sunday. Temperatures will struggle to get into the twenties until Tuesday. Chilly nights of around 8C.

Tropical moisture and humidity will be a feature of the Top End. In Darwin, a smattering of rain on Saturday and then some heavier falls on Sunday. Highs of 33C will give away to nights in the mid twenties.