Half of country set to be drenched, other half roasted

Northern New South Wales and Queensland could see storms and flash flooding and South Australia is looking at its heaviest rain potentially for more than 10 years.

In complete contrast to that, Melbourne is hunkering down as scorching temperatures are expected for the Australian Open with seven days above 30C while Perth is set to breach 40C as a 1700 long heatwave hits Western Australia.

Sky News Weather meteorologist Alison Osborne said the weather was “a different story entirely,” depending on what state you were in.

Rain for NSW, Queensland and Northern Territory

Much of the current rain has been caused by the remnants of Tropical Cyclone Tiffany which is swirling around central Australia, interacting with other weather systems, and firing off bands of rain towards the south and east.

“Now, a high pressure system in the Great Australian Bight is helping to direct south-easterly winds about the NSW coast and that’s helping to pump moisture inland towards a trough and as we head into the end of Thursday, focusing showers and storms about the coast and the inland of Queensland”, Ms Osborne said.

That means Sydney is seeing a very drizzly Wednesday with persistent rain. But that looks likely to fizzle out as the weekend nears with just the odd shower.

Temperatures are curently in the mid-twenties but will slowly move up toward 30C over the week.

It’s dry in Canberra today with a high of 21C, but reaching 27C on Sunday which will be similar for much of southern NSW.

That moisture seen in Sydney will move north over the coming days with more than 50mm potentially falling between Wednesday and Friday in Coffs Harbour and Byron Bay, though isolated pockets could see much more.

It will then cross the border into Queensland. Brisbane is forecast to get some rain today and potentially another 20mm leading into the weekend.

The Gold Coast is set to be wet for the next week with 15-40mm falling in the next four days.

Across south east Queensland thunderstorms, with concentrated drenchings, are a possibility.

“As catchments are fairly saturated, rivers will respond quickly at this stage and minor flooding and potential road cut offs are likely,” said Ms Osborne.

Rain could feature all the way up the Queensland coast with as much as 20mm falling in Cairns on Friday and more for the weekend.

Darwin, which Tiffany brushed last week, will see heavy rain and storms every day this week with up to 20mm on average expected to fall. The city will top out at 32C.

Soaking for South Australia

But all eyes are on South Australia where forecasters warned yesterday the “heaviest rain event in a decade” could be in the works.

A line of precipitation may essentially stall over central parts of the state between Thursday and Sunday, dumping large amounts of rain – up to 200mm in some places. That’s a level of rain not seen since February 2011. The prognosis will become clearer over the coming days.

The rain forecast for Adelaide has now been increased. Up to 35mm on Saturday could fall with a further 20mm on Sunday.

Port Lincoln is currently looking at 70mm of rain over four days from Thursday with as much as 85mm in Port Augusta and similar in Whyalla.

It will be hot in SA, however, with 35C forecast for Thursday and Friday and 30C plus temperatures all weekend.

Soaring temperatures for south and west

And it’s heat, not rain, which is the main event in much of the country’s south and west.

The Bureau of Meteorology is forecasting two areas of heatwaves for Australia in the coming days. A low-intensity to severe heatwave will stretch across south eastern SA into Victoria and Tasmania into the weekend.

While a 1700-kilometre monster heatwave will take in much of the Western Australian coast, from Albany to Exmouth including Perth.

“The next three to four days are looking very hard both at night, and during the day for you in Perth,” said Ms Osborne.

“Temperatures climbing into the forties along the coast, thanks to very light sea breezes.

“It’s going to be hot and uncomfortable with the increased risk on bushfires.”

There will be a high of 41C on Wednesday and not much lower than that every day until Sunday in WA’s capital. Overnight, expect temperatures to be as high as 26C.

Albany could hit 35C on Wednesday and 30C on Thursday and Margaret River may reach 37C on Wednesday.

In Melbourne, the mercury will peak at 30C on Thursday and then steadily climb to 35C on Sunday. Overnight lows will be around the high-teens or low twenties.

It will be dry in Hobart and getting warmer. A high of 20C on Wednesday and then hitting 25C on Friday and Saturday with minimums of 12C.

Originally published as Half of country set to be drenched, other half roasted as severe weather engulfs Australia