Millions of Australians face an explosive final few days of spring, with heatwaves, storms and flooding expected to smash several states.

The weather bureau has warned of severe heatwaves across large swathes of NSW and far north Queensland that could send temperatures spiralling towards 40 degrees.

Wild storms and rain – with the possibility of large hail and damaging winds – are also expected to hit every state and territory in coming days.

The storm bands could dump huge rainfall close to or above the average monthly totals for November, meteorologist Jonathan How said.

This could lead to flooding in areas where storm bands settle and unleash rainfall.

The weather warnings come on the last week of spring, and have prompted warnings about potential blackouts and brownouts.

There are severe heatwave warnings in NSW and Queensland until Thursday, with temperatures predicted to decline on Friday.

Parts of western Sydney, including Penrith and Richmond, were tipped to hit 39 degrees on Tuesday, while Liverpool and Campbelltown were looking at temperatures of 36 degrees.

The forecasts were well above spring norms, with Richmond’s prediction a whopping 12 degrees above its average November maximum temperature of 27.

Regional areas won’t be spared, with the weather bureau issuing severe heatwave warnings for the Hunter region and the south coast.

Sydney is forecast to reach 31 degrees, well up from the November average maximum temperature of 24.

Many remote areas north of Cairns have been hit with heatwave warnings and BOM meteorologist Jonathan How How said there was no respite in sight.

“Even two to four degrees above average in those areas has temperatures pushing into the 30s, so hot days and hot nights and really no relief on the way,” he said.

Temperatures in Canberra are predicted to reach a peak of 31 degrees on Tuesday.

A big week of rain and thunderstorms to round out spring in Australia. While wet and stormy weather will hit part of every state and territory, this week’s heaviest falls will occur over an arc stretching across northern and eastern Australia.

Details: https://t.co/TPpTNgsK3H pic.twitter.com/Wg5XrNEyZJ

— Ben Domensino (@Ben_Domensino) November 25, 2024

How said the week would get wetter as it progressed, with storms across much of the country.

“It’s going to be a wet week ahead for much of Australia, with rain and storms expected across every state and territory,” he said.

“By Wednesday, we could see accumulated rainfalls exceed 50 millimetres across parts of Victoria and the Northern Territory.

“From Thursday and Friday, that’s when we start to see rainfall totals building in NSW and southern Queensland.

“This will help to ease some of those heatwave conditions through there, and by Friday night we could see large parts of the country approach or even exceed the average monthly rainfall for November.”

He said the driving factor behind the consecutive days of heavy rain was sea surface temperatures approaching 30 degrees.

In north-western Australia, the sea temperature is hitting 32 degrees.

The hot water temperatures created extra vapour, which How said was “fuel” for thunderstorms.

The Australian Energy Market Operator had feared that demand for air-conditioning use and generator repairs at three NSW coal-fired power plants could shut the grid down in some areas.

On Tuesday, the regulator said NSW would have the requisite electricity supply to get through the day, although there was still a chance of shortages later in the week.

“Ongoing heatwave conditions combined with significant generation outages in NSW tomorrow and Thursday remain a risk,” a spokeswoman said.

“AEMO is actively managing the situation and has issued updated Lack of Reserve notices, urging industry participants to respond to projected demand requirements in the coming days.”

BOM warned severe heatwaves could be dangerous for many people, including pregnant and breast-feeding women, babies, older people and those with medical conditions.

-with AAP