A bubble of hot air is slowly drifting across the country with its target the New South Wales coast.

“Some places, maybe Sydney, could be hotter than anything we’ve seen through the entirety of summer,” said Sky News Weather meteorologist Rob Sharpe.

In the run up, however, it will be milder with some rain in the east of the country.

In parts of Queensland and Western Australia a heatwave will be the dominant feature into the weekend while the rain shows no sign of stopping in the nation’s north with widespread flood warnings.

A heatwave in WA has stretched from near Margaret River all the way up to Carnarvon including Perth for much of this week.

It will now ease back and should be gone by the weekend. It’ll still be toasty in Perth on Thursday with a high of 37C but that will drop to a 31C maximum on Friday before settling into the high twenties across a sunny Saturday and Sunday with mid-teens lows.

The mercury could crank up again to the mid-thirties on Tuesday however.

Thursday will see a grey and mild 24C in Adelaide. The sun should come out on Friday with a high of 27C and then 28C on Saturday. There could be some showers on Sunday and into next week where the mercury will fall down to 20C highs. Dawn minimums will be around the 13C mark.

Mostly dry and cloudy in Melbourne, settling around 21C for the next couple of days and then pushing into the low thirties on a partly sunny weekend with 15C minimums.

But the temperature will fall once more after the weekend as a cold front sweeps through peaking at just 19C on Wednesday.

There will be a similar see sawing in temperature in Hobart with 21C on Thursday, rising to 25C on Sunday and then just a 17C high on Wednesday. Some heavy downpours are to be expected in the middle of next week.

Canberra will inch up to 30C by Sunday preceded by 28C on a cloudy Thursday and 27C on Saturday. Storms are possibility across the weekend in the afternoon and evenings.

The warmer weather could persist into next week but will drop to 21C by Wednesday.

‘Hotter than the entirety of summer’

Head north and the heat will be bubbling up said Mr Sharpe.

“A heat spike will be over southern inland Queensland and then NSW where on Sunday there will be some elevated fire danger as the wind picks up.

“Then on Monday, that heat runs all the way down the NSW coast where there is the potential for that heat to be hotter than anything we’ve seen through the entirety of summer.”

It’s a big call – but it could well stack up.

Sydney’s CBD actually hasn’t had a day above 31C all summer. The hottest it got was a 30.6C maximum in February.

Yet on Monday and Tuesday, 33C is being forecast in the city centre with possible storms. Expect lows of around 20C.

Penrith in the city’s west, could get to 37C on Monday. That won’t beat the summertime high of 38.6C on February 11, but it might not be far off.

Further inland, Walgett could reach 39C on a windy Monday, Maitland 37C on Tuesday and Moree 36C the same day.

“But then we’ll see a bit of a cool change coming up by Wednesday,” said Mr Sharpe.

Sydney should drop to a maximum of 28C by midweek next week.

Brisbane will be bobbing around 30C for the coming week with 20C lows. There could be light rain on Friday but other than that sunny with a few clouds.

A heatwave will remain in place on Thursday, and in some areas on Friday, across inland southern Queensland. Roma is forecast to reach 38C on Thursday and 35C on Friday. Indeed, it’s not forecast to hit a maximum below 33C for the next week.

Non stop rain for the north

Northern Australia is looking very wet with a monsoon that’s just hanging around.

“It’s expected that this monsoon low will strengthen again through next week and even looking out 10 days almost there’s still no end in sight to this system,” said Mr Sharpe.

Areas round the Gulf of Carpentaria will likely see the most moisture.

For Burketown, 10-35mm is possible on Thursday, then up to 50mm on Friday and 60mm on Saturday and it just continues on in that vein into next week.

Some of the rain could get to the Queensland coast in the coming days with up to 20mm of rain in Cairns on Sunday rising to potentially 60mm on Monday.

In the Northern Territory, Tennant Creek is looking sodden with 10-80mm of precipitation on Thursday.

The Bureau of Meteorology has major flood warnings in place for parts of the Top end and central inland and Carpentaria coast catchments.

Darwin is a bit further from the monsoon’s grip so won’t be as wet. Thursday could see up to 15mm and 31C highs but 45mm could fill the gauge on Friday before the rain lessens only to crank up again on Monday. How much falls will very much depend on where the system heads.