A shift in weather conditions is forecast to bring showers and thunderstorms to parts of Australia on Sunday, marking the end of an intense heatwave across the southeast.

Temperatures are dropping dramatically in the wake of a cool change, expected to fall to a high of 20C in Melbourne on Sunday afternoon.

The city endured its hottest day in nearly 17 years on Tuesday, as the mercury climbed to a scorching 45C.

Sky News Weather Senior Meteorologist Rob Sharpe says showers, thunderstorms, and even snow are set to impact parts of the country.

“Finally, the cool change is sweeping across southeastern parts of the country, dropping temperatures and bringing showers and thunderstorms. We’re expecting more of that throughout Sunday afternoon and evening,” he said.

“For Brisbane, still on the warm side of things – heading for 33C. They won’t get their cool change until Monday.

“But for Sydneysiders, pretty warm until that change arrives during the late afternoon into the evening, when showers and thunderstorms are likely to come through.

“In Melbourne, looking pretty cold – just 20C with a chance of a shower in the morning, fine but cold for the Australian Open final.

“Whilst in Adelaide, 25C and mostly sunny. Staying hot on the west coast, 37C in Perth.

“For the southeast, there will even be some snow in Tasmania as low as 900m above sea level with just a 16C forecast in Hobart.”

Meanwhile, the Bureau of Meteorology (BoM) is monitoring a tropical low, 18U, currently located over land near the Queensland/Northern Territory border.

“The system may remain over land, but if it drifts over Gulf of Carpentaria waters, there is a chance it could intensify into a tropical cyclone over the weekend or early next week,” forecasters warned.

“There is potential for increased rainfall affecting Far North Queensland, the Gulf Country, and the adjacent Northern Territory associated with 18U. Next week, 18U may move westwards across the Top End.”