Plunging temperatures and widespread frost are expected across large parts of south-eastern Australia this week as a polar air mass whips across the country.
Meanwhile, a thick rain band, fuelled in part by “unusual” tropical moisture, is set to deliver rain to every state and territory by the end of the week.
It has already been a bitterly cold start to the week.
On Monday morning, Sydney’s Olympic Park observation site recorded its coldest June morning on record, dropping to 1.8 degrees Celsius.
Mudgee and Glen Innes in New South Wales fell to -6C, and Bathurst and Orange both neared -5C, while heavy bouts of snow fell in Victoria and New South Wales.
The cold snap came as a strong cold front pushed across south-eastern Australia.
Most of the rain has now passed, but the frigid temperatures are far from over, according to the Bureau of Meteorology, with widespread frost expected.
According to the forecast, large parts of the south-east will fall to sub-zero temperatures again for the next two days.
The bureau’s main forecast tool, MetEye, showed overnight minimum temperatures falling to near below freezing from southern Queensland to Tasmania on Tuesday and Wednesday.
At the same time, some parts of southern Victoria, New South Wales, and Tasmania will struggle to reach double digits during the day.
Senior meteorologist Sarah Scully said these temperatures were between 4 and 8 degrees below average overnight and up to 6 degrees below average during the day.
“The clear skies really just allow the temperatures to plummet,” she said.
Frost has also been forecast from inland southern Queensland through most of inland NSW and Victoria and north-eastern Tasmania, as well as a small section of WA’s Wheatbelt.
“Tuesday and Wednesday are looking like particularly cold mornings for southern Australia, returning to more normal conditions later in the week,” Ms Scully said.
“The coldest temperatures will be concentrated about Victoria on Tuesday morning, whereas on Wednesday morning those minimum temperatures really start to push into New South Wales.”
Some stand-out temperatures include a minimum temperature forecast of -8C for Mount Hotham on Tuesday morning.
On Wednesday morning, minimum temperatures of between 0C and 3C are forecast for Sydney’s west, including Penrith.
Ms Scully said some more elevated areas of the New South Wales tablelands had the possibility of a dusting of snow, including Orange and Oberon overnight Monday into Tuesday.
The Stirling Ranges, in Western Australia’s south-west also have a chance of getting snow about the peaks, which is typically only experienced once or twice a year on average.
Unusual tropical rain to hit every state and territory
As the cold air grips the east, a large-scale cloud band fuelled in part by “tropical” moisture has been developing in the west.
It is set to deliver rainfall to every state and territory by the end of the week as it links up with a cold front in the south-west.
It comes only a few days after another storm system off south-west WA produced an enormous swell off WA’s south coast.
Ms Scully said the cloud band was already bringing showers and rain areas across much of WA, apart from the Kimberley.
She said it would move toward central Australia on Tuesday and Wednesday, reaching south-eastern Australia on Wednesday and Thursday.
While the feature is a fixture of the weather charts during the summer months, Ms Scully said it was more “unusual” for this time of year.
“There is already a really large area of cloud that’s developing over WA at the moment and that’s from an upper-level trough,” she said.
“It’s basically just building the humidity and moisture up through that area, and then we’ve got a cold front that’s coming in from the south joining up with that system.
“So it’s just a combination of the two systems, and the cold front will drag all of that moisture eastwards reaching the south-east on Thursday and Friday.”
Ms Scully said the rainfall totals for southern Australia would be fairly typical.
But she said it would bring rainfall to several regions that typically saw nothing but blue skies this time of year, including the Pilbara in WA.
“So, in that sense, it’s unusual for them to get these sort of rain bands sweeping across,” she said.