NSW Rural Fire Service firefighters fight a fire on Medowie Rd, at Medowie near Port Stephens, early this month. Picture: AAP Image.

An extreme heatwave is due to hit southeast Queensland on Friday with Brisbane set to swelter its way through the hottest December day in 15 years.

The mercury is unlikely to dip below a high of 30C for the next week and could get up to 40C tomorrow. That would equal the previous record set on Christmas Eve 2001.

But it’s the sheer amount of rain we’ve had that could turn a balmy summer into a horror bushfire season.

In preparation for the upcoming high temperatures, hospitals in the Sunshine State have been put on alert for an influx of heat-related injuries.

And it’s not just Queensland in for a king hit of heat.

NSW, South Australia and the Northern Territory will also experience stifling conditions with the heatwave crossing the border and heading south towards Sydney. Tomorrow, parts of the city could reach 38C.

The Bushfire and Natural Hazards Cooperative Research Centre’s bushfire outlook shows large parts of NSW and Victoria have the potential for fires.Source:Supplied

NSW Minister for Emergency Services David Elliott said the omens weren’t good for the coming season.

“(Today) is the first day of summer and it is shaping up to be an extremely challenging season with hotter and dryer conditions expected across the state,” he said.

However, while Queensland may be bearing the brunt this weekend, it’s NSW and Victoria where the biggest risk lies in the coming months.

So what’s causing the upcoming heatwave and what does it mean for summer?

An extreme heatwave is predicted from Friday in Southern Queensland and northern NSW.Source:Supplied

HEATWAVE

The Bureau of Meteorology has said the current heatwave is steadily developing over northern and Central Australia. The air gets nice and toasty over the desert and then weather systems distribute it across the continent.

This week, that dry heat will head east towards southern Queensland and northern NSW, becoming “severe” sometime today and then “extreme” tomorrow.

According to the Bureau, a heatwave is defined as three or more days of high maximum and minimum temperatures that are unusual for that location. Temperatures in southern Queensland are likely to sky rocket a full 10C hotter than the average.

Severe heatwaves are a danger for vulnerable people such as the elderly and pregnant women.

“Even rarer and exceptionally intense heatwaves are classed as extreme and will impact normally reliable infrastructure, such as power and transport,” the Bureau states.

“Extreme heatwaves are a risk for anyone who does not take precautions to keep cool, even those who are healthy.”

NSW Rural Fire Service firefighters fight a fire on Medowie Rd, at Medowie near Port Stephens, early this month. Picture: AAP Image.Source:AAP

HORROR SUMMER

But what of the rest of summer 2016?

The Bushfire and Natural Hazards Cooperative Research Centre has warned a chief worry is the bucket loads of rain which have fallen during winter — particularly across inland NSW, Queensland and much of Victoria.

This has spurred a huge amount of plant growth which, when conditions heat up, is ripe for burning.

This year saw the wettest September on record. Next month, temperatures are 80 per cent likely to exceed the usual average across the entire east coast and central areas.

Only Tasmania and south west Western Australia are likely to escape the punishing heat.

President of the Fire Brigades Employees Union, Darrin Sullivan, whose members are on the bushfire frontline, said he was concerned about summer 2016.

“The wet weather has increased the fuel loads and it’s also hampered the fire service’s ability to put in hazard reductions.”

Three climatic conditions are positioning themselves around the continent to deliver a horror season.

In the Pacific, the El Niño weather system has come to an end but its counterpart, the La Nina, which sees cooler sea temperatures leading to more rainfall in Australia, never really got started.

In the Indian Ocean, another weather system — the Indian Ocean Dipole — had been pushing wetter weather towards Australia. But that has begun to peter out.

The third system of this weather trifecta is the Southern Annular Mode, or SAM. Essentially a bunch of winds sweeping up for the Antarctic these are predicted to push north and, in the process, could actually blow away the rain from the continent that might otherwise have dampened conditions.

The Southern Annular Mode is reducing rainfall across southern Australia.Source:Supplied

Mr Sullivan said there was a fourth issue in play: climate change.

“We’ve been raising the dangers of climate change and bushfires for a good two or three seasons and we are about to go into another hot summer and fire dangers are getting worse,” he told news.com.au.

“What we’re seeing is evidence of extreme weather that’s having an all year round impact and much more dangerous conditions. “

He said efforts to control bushfires were being stymied by funding cuts to fire services, both rural and urban.

“Government at all levels need to take climate change seriously and they’re just not,” he said. “We need more firefighters on the ground and we need better equipment.”

The weather bureau has advised those in the path of the heatwave to take care.

“When temperatures are unusually hot over a period of time, with continuously high night-time and daytime temperatures, heat stress becomes a critical factor in human survival and infrastructure resilience.”

Queensland’s health authority has put in place contingency plans in areas that could be heatwave-affected.

Queensland Health’s Peter Aitken said the effort would ensure that the most vulnerable people received care.

“We’re using exactly the same processes that we would normally use to ensure our hospital and health services are prepared, whether it’s for a heatwave, a cyclone that’s coming, a flood or a pandemic event,” he told the Courier Mail.

“We can’t change the heatwave, that’s nature, but what we can do is make sure people are informed and minimise the impact.”