An enormous dust wall has swept across vast areas of New South Wales and ACT as a fierce cold front rip through the state, picking up land and sand from within and dumping it further inland.
It's already covered by Canberra, and the dust is on its way to Sydney as the cold front march north.
Satellite images have shown the dust flow from NSW in a large band through the state down to the south coast. A live fake color chart from the Bureau of Meteorology has shown the dust cloud's progress across NSW as a pink swath.
It came on a blistering Tuesday for Sydney, reaching 36.3 C in the CBD and 38.3 C in Penrith, in the city's west.
Kl. 18.30 on Tuesday it was still 34C in the port city. In northern parts of the state, fires have raged in baking conditions.
Yet south of the border, it has been a completely different story. At noon on Tuesday it was so cool that it was the second coldest temperature recorded in Melbourne this year – the first one was in the middle of the night.
While north of the border, storms have rushed through the southeast, while the floods continue their relentless march to the oceans.
Sky News Weather Channel meteorologist Rob Sharpe told news.com.au Sydneysiders should prepare to clear a dustbin on Wednesday morning as a wave of dust baths the state in fine red dirt.
"There are dust storms over the NSW and it is spread over a very wide area, all the way from the border region of Queensland and South Australia near Tibooburra and right down to the ACT and even to the South Coast of Ulladulla.
"A strong cold front, stretching through the southeast, picks up dust, and it could easily enter Sydney, probably overnight."
The cooler weather would probably reach the city around midnight, he said, which could see mercury falling dramatically by Wednesday, struggling to reach a height of 26C, 11 degrees below Tuesday's high.
Canberra will see 24C on Wednesday, and then mercury will probably come back to mid-30s over the weekend.
The windy, warm conditions have led to bushfires in the northern part of NSW. The State Rural Fire Service said at 7pm there were 51 bush and grass fires burning. Of these, 19 were not yet included, and two remained at emergency level.
An unguarded grass hat is burning west of Tabulam, where the authorities warn that it could spread to the nearby Jubullu Aboriginal settlement on Tuesday afternoon.
An emergency has also been issued for people near a fast-flowing bushfire burning south of Inverell in northern NSW, which has already burned nearly 1000 acres.
Firefighters and aircraft have not been able to slow down the fire burning to the east of Lake Copeton and spread rapidly toward Tingha. Properties threatened.
A state fire ban issued on Tuesday has been extended to Wednesday for the state's northwest, distant north coast, northern slopes and New England regions.
In Queensland, severe storms passed through the Sunshine Coast during the early evening.
Further south, Brisbane continues to swell Mr Sharpe said: "Brisbane got to 35C on Tuesday, making it the 34th consecutive day over 30C, so it has only been an unusual term of consistent heat.
"But we reach the top of the heat for Brisbane. Wednesday will be 36C, and then there will be a cool change on Thursday. It's not a huge, cool change for Brisbane, but it comes to around 30C Friday and Saturday.
CHILLY I MELBOURNE
Then you had south of Murray, where the cold front has already gone through, and it is practically scarf weather.
"In Melbourne, the cool change flew through late morning on Tuesday with temperatures falling from 21 C to 15 C in just 20 minutes," Sharpe said.
"It even came down to 12.7 C, which is where it bound out, and that's the second coldest temperature Melbourne has seen this year. It came to 12.6 C (February 1), but it was early in the morning and it was dinner and with the wind chill factor it would have felt below 10 C. "
Snow now developed in Tasmania as low as 900m, he said.
Wednesday is unlikely to be as cold or as windy as Tuesday in Victoria, Tasmania or South Australia with much quieter conditions.
"We see that sunshine is growing and the showers are falling as we move through the day," said Mr Sharpe.
A low of 11C and a high of 19C in Melbourne with Hobart just a little cooler. Adelaide will reach 22C.
In Perth you expect a sunny high of 33 C on Thursday and the same in Darwin, but with added storms in the Top End.