Snow in Thredbo, heatwave in Sydney: extreme weather in NSW

NSW is now a land of extreme weather: snow blankets the Alps while much of the state’s coast bathes in temperatures of over 30 degrees ahead of a scorching weekend.

Meanwhile, Brisbane is among the wettest cities on earth, and hail hits Melbourne with a cold snap from Antarctica.

Sydney is expected to hit 31 degrees on Friday, with light winds and a near-zero chance of rain, reflecting a hot and humid trough moving down from Queensland.

“The heat in southeast Queensland and northeast NSW has high humidity,” Weatherzone’s James Rouse said. “[It’s] This makes for very warm mornings and it feels hotter than it is.”

But further south, in Thredbo, snow is falling as the state’s southeast experiences an Antarctic-induced cold snap, resulting in temperatures “that are very cold for this time of year,” Rouse said.

“The air at the surface is not from Antarctica, but the air is five or six kilometers above the ground,” he said. “It’s generating strong winds making it several degrees colder, along with thunderstorms and showers [making it feel even colder].”

The sharp contrast at the extremes is driven by two competing weather systems – the valley over the northeast and the low coming from Antarctica – as well as the effects of geography. Colder air coming in from the west falls en route across the Great Dividing Range, which warms the air as it flows further towards the coast.

This leads to the strange result that some towns on the western side of the range are relatively cooler than those on the eastern side.