Gabrielle Woodhouse, a forecaster at the Bureau of Meteorology, said some parts of the state were "particularly dry and strong winds can easily pick up the dust". Those winds need to be sustained for several days, though, to carry the dirt over the Great Dividing Range.

Canberra and the south coast, as well as Sydney, could be affected by the dust, more likely on Thursday, when winds strengthen again, Ms Woodhouse said.

"It's more likely tomorrow that we could see something like that," she said.

"Getting towards Sydney is a bit more in the 'iffy stakes' at the moment, but is one of the strongest signals [for dust storms] that we have seen so far," Ms Woodhouse said.

"We are looking at quite a windy day tomorrow and into Friday," she said.

A low-pressure system near Adelaide will shift towards Tasmania, dropping temperatures sharply.

On current forecasts, Sydney's top will drop from 29 degrees on Wednesday to 25 on Thursday, but with westerly winds reaching 45 km/h, conditions could feel a lot cooler.

"The combination of cool temperatures and the winds will mean we'll have that wind-chill factor starting to play in," Ms Woodhouse said.

Snow showers may reach down to 1100-1200m in some mountain areas in the southern Alps as a cold front moves across the state.

Eastern South Australia and far-western Queensland, areas with typically little vegetation, are typically sources of dust storms. Ongoing drought conditions across much of NSW, however, have increased the size of those regions.

Warning issued

The bureau, meanwhile, issued an alert warning of a range of wild weather events possible on Thursday.

Aside from the raised dust, severe thunderstorms are possible for northern and southern parts of NSW and the ACT, it said in a statement.

Despite the brief shift to cooler temperatures, the ongoing parched conditions across much of the state means bushfire risks will also be elevated in coming days.

"Strong winds and very low humidity will lead to 'Very High' fire danger on Thursday and Friday for many parts of New South Wales, including areas around Sydney, Newcastle and Wollongong," it said.

'I was a little bit nervous'

Tuesday's dust storm comes two weeks after similar conditions in the same NSW town.

On November 6, White Cliffs was blanketed in thick dust as a "wall of dust" descended on the region.

Barry Turner, 65, was driving from his property towards White Cliffs in outback NSW when he was caught inside what he calls a "wall of dust".

"I had to get home, but I didn't think it was going to be quite as bad as what it was," he said.

"It got pretty dark so I pulled over to the side of the road and waited for it to pass."

A video posted online shows Mr Turner's car driving towards the huge cloud of dust before plunging into complete darkness.

"Not much scares me but I was a little bit nervous."

Mr Turner and his wife, Annette, 65, have lived in the area for 56 years and have seen a few dust storms - but yesterday's was only the second one they've seen that was this extreme.

"They get a little bit darker but they're never as dark as that," said Mrs Turner.

"It is a bit scary when it goes black. It just makes you feel uncomfortable."