Australia’s east is facing a weather double whammy with both an “unprecedented heatwave” and flooding rains as two systems roll across the country.

Today Cairns sweltered through its hottest day ever recorded as the mercury peaked at 41.3C.

Meanwhile an atmospheric phenomenon, known as a gravity wave, has bounded across Melbourne.

The forecast comes as bushfires punish Queensland with two houses lost and another eight under threat from an out-of-control “monster” blaze focused on the state’s central coastal area. Hundreds of residents have fled thier homes.

“Queensland is facing an unprecedented heatwave which is already under way with temperatures soaring up into the 30s and even 40s in central and tropical parts,” Sky News Weather channel meteorologist Rob Sharpe said on Monday.

Yet, in NSW, the middle of the week is looking like a washout with as much as 100mm of rain falling in places and storms across the coast.

‘MONSTER’ BUSHFIRE

In Queensland, the current heat is causing consternation to firefighters who are struggling with a bushfire close to Agnes Water, between Bundaberg and Gladstone.

The Queensland Fire and Emergency Services has said “conditions are getting worse” around the 11,000ha Deepwater fire. They have advised residents of Round Hill, Baffle Creek and Rules Beach to evacuate while they still can.

Gladstone Regional Council Mayor Matt Burnett said hundreds of people were fleeing threatened communities and firefighters faced a very difficult task trying to control what he called a “monster” fire, reported AAP.

NSW has lent Queensland its new ‘Gaia’ air tanker, a converted Boeing 737 jet that can dump 20,000 litres of water on the flames.

“It’s going to a be a very dangerous week with fire danger from very high to severe on many days in many areas of the state,” Mr Sharpe said.

Pleased to be assisting our #QldFES colleagues with fire fighting. Responding to a request this morning, 'GAIA', the 737 LAT, as well as Bird Dog Air Attack platform, are already in QLD and helping and 100 #NSWRFS rural fire fighters are on the way today to assist over next week. pic.twitter.com/TgLSKoXSi9 — Shane Fitzsimmons (@RFSCommissioner) November 26, 2018

HEAT RECORDS TUMBLING

Charters Towers, Rockhampton, Mt Isa are Emerald are just some of the places that could see the gauge push above the 40C mark early this week as “pulses” of hot wind rush through, he said.

“The heat is lingering; there are very hot temperatures and gusty winds in central parts but that heat is not going anywhere.

“Cairns broke its November heat record at 9.30am on Monday passing the previous record of 37.2C,” Mr Sharpe told news.com.au.

That record was set in 1971 with records dating back over 130 years ago.

At 39.6C on Monday morning, Townsville was in sizzling distance of its November record of 41C set in 1971 while Mackay has broken its record for this month for the third day in a row reaching 39.7C at 10.24am.

“We’re talking about unprecedented heat and that it has lasted so long, that hasn’t happened in November before according to our records,” Mr Sharpe said.

It will be cooler in the southeast — but only by a touch. Expect 34C several days this week in Brisbane.

Mr Sharpe said it could be next week until a cool change swept across Queensland.

UP TO 100MM OF RAIN

But head down into the southern states and it’s rain that will be the notable weather event this week with a low pressure system heading in from Western Australia.

“We have a rain band pushing through late Monday and Tuesday across South Australia but as it comes across the country it will deepen in NSW as it interacts with coastal moisture,” Mr Sharpe said.

It will be 24C in Adelaide on Monday and towards the end of the week. But Tuesday could see the mercury fall to 19C as up to 25mm of rain falls.

But that’s nothing compared to NSW.

“We’re looking at heavy falls particularly in central areas of NSW where we could see flooding rainfall — in isolated areas as much as 100mm.”

Wednesday will be the wettest day for Sydney with a possible storm and a two-day rain total of as much as 50mm. There will be highs of around 23C all week with night-time lows of 16-19C.

Canberra will also see some of that rain on Wednesday which will peak at 19C, a substantial drop on the high of 27C on Tuesday.

The rain event will then float off out to sea with conditions easing on Thursday.

Melbourne may see a touch of rain on Wednesday, as the southernmost fringes of the rain event pass over. But Victoria’s capital will be generally dry this week with highs in the low 20s.

On Monday morning, Melburnians may not have known it, but a gravity wave passed 2km above their heads.

Many of us see gravity waves all the time — they’re the waves that crash on the beach. But it was the airborne equivalent that appeared in Victoria on Monday morning.

Gravity waves appear at the boundary of different atmospheric regions, such as the troposphere and stratosphere, and transfer momentum between the two.

The morning’s gravity wave probably began its life in northwest Victoria and then travelled south.

“The basic physics is much like ocean waves or ripples of a stone thrown into a pond. (They) can cause turbulence for planes, kickstart storms, or just look nice,” said the Bureau of Meteorology on social media.

A gravity wave is visible just to the north of #Melbourne - likely generated in NW #Victoria & having travelled south at a height of 2km along the inversion (where temp increases sharply with height, usually air cools cools with height)

📷 Himawari-8 https://t.co/F71arc6xjX pic.twitter.com/m8gmIlOFdM — Bureau of Meteorology, Victoria (@BOM_Vic) November 25, 2018

Further south, it will be a cloudy week in Hobart with patchy rain and temperatures reaching 18-20C.

And across the Nullarbor, it’s a sunny and warm week in Perth with highs of 27C on Tuesday and Saturday and around the mid-20s on other days. In the Top End, Darwin will see highs of 35C with some storms and showers later in the week.