Two heatwaves and 'once in a lifetime' rainfall hit Aussie states

Parts of Australia have been hit with 'once in a lifetime' levels of rain, while others are continuing to sweat through extreme heatwaves.

South Australia's north and west have recorded 50 to 150mm of rain over the past few days — half the annual average in some areas.

The record-breaking rain and stormy weather is expected to last until at least Thursday, with a further 100mm of rain and further flooding in the north and west predicted.

A section of road was washed away between Pimba and Woomera on the Stuart Highway in South Australia. Source: Spud's Roadhouse/ Facebook
A section of road was washed away between Pimba and Woomera on the Stuart Highway in South Australia. Source: Spud's Roadhouse/ Facebook

This could leave outback communities stranded if roads flood. State Emergency Services (SES) are urging residents to be careful when driving.

"If you come across water over the road, turn around," the South Australia SES warned.

"Stay safe by never driving through floodwater."

Heavy rainfall edging east to NSW and QLD

The heavy rainfall is due to two factors: higher-than-usual amounts of tropical moisture and a low-pressure trough moving slow enough for this moisture to reach levels rarely experienced before in the state.

The slow-moving, moisture-filled systems is causing the extreme rainfall and thunderstorms.

The wet weather will gradually ease with the heavy rainfall edging east over the next few days to NSW and Queensland.

Severe thunderstorms in northwest South Australia

According to Weatherzone it's a "once-in-a-lifetime" rainfall, saying it's the "biggest rainfall" in at least 100 years for some regions in outback SA, including Kimba, Mount Ive, Darke Peake and Wirrulla. It'll be the highest rainfall in 76 years in Yardea, 55 years in Wharminda and at least 50 years in Cowell.

The Bureau of Meteorology said severe thunderstorms were developing throughout Monday due to a "humid and unstable" airmass ahead of a trough of low pressure over the Eyre Peninsula and the North West Pastoral district.

BoM issued a severe thunderstorm warning of flash flooding due to the thunderstorms on Monday morning with possible affected areas including Arkaroola, the area east of Lake Frome and the Strzelecki Track south of Moomba.

Map showing Australia's weather forecast for Sunday, January 30.
Perth's temperatures are expected to hit 40 degrees again on Sunday as illustrated by the purple shading. Source: Stormcast

Perth and Melbourne experiencing heatwaves

Perth recorded its sixth day in a row of scorching 40-degree temperatures on Sunday.

Thankfully for West Australians, the temperature is expected to drop on Monday with a weak cold front expected to sweep across the southwest, dropping the temperatures to the low 30s over the coming three days, according to Weatherzone.

In this photo illustration a thermometer is pictured at Cottesloe Beach on January 22 in Perth, recording temperatures of 40 degrees for the fifth consecutive day this week.  (Photo by Paul Kane/Getty Images)
Perth has recorded temperatures of 40 degrees for the six days in a row. Source: Getty Images

However the cool relief will be short-lived, the mercury is expected to rise again from Friday with a high chance of Perth reaching scorching temperatures of 40 over the next weekend.

Melbourne is also set for a warm week. It reached 32.6 degrees on Sunday and 32.3 on Saturday, with BoM predicting the city is set for an “extended run” of heat this week.

"Since Thurs we have had 30.4, 29.6, 32.3 with forecast temps to come: 34, 35, 33, 33, 30, 27," BoM Victoria tweeted.

It added the run of hot temperatures is not a record.

"..The longest run of 30°C+ in Melb was 9 days, back in March 2013," the bureau said.

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