Sydney, Melbourne, Brisbane weather: Dire warning to millions of Aussies as sweltering heatwave

Temperatures could soar up to seven degrees above average across parts of Queensland as bushfires force hundreds to flee their homes.

Bureau of Meteorology meteorologist Angus Hines says Friday will be 'another hot day' for the Sunshine State, with temperatures set to rise 5-7C above average for this time of year across the east coast and eastern interior.

However, thunderstorms could also be on the radar , with the potential for damaging wind gusts.

'We do expect to see some showers develop across the southeast as well, with possible thunderstorms,' Mr Hines warned.

'We could even see some severe thunderstorms through some southern areas.

'At the moment, it's looking most likely that would be around the scenic rim and the border ranges, but potentially could spread through other parts of southeastern Queensland through the afternoon hours.

'If those storms do develop, expect areas of heavy rain and damaging wind gusts, dry and sunny from around about Bundaberg northwards up the east coast.'

The Bureau of Meteorology earlier issued a heatwave warning on Wednesday for much of the state's northwestern and central regions and as far south as Brisbane.

The worst-affected areas were forecast to potentially receive extreme heatwave conditions and included territory around Mount Isa and Richmond.

A severe heatwave warning remains in place for the Gulf Country, Northern Goldfields and Upper Flinders, Central Highlands and Coalfields, Central West, North West, Channel Country, Maranoa and Warrego, Darling Downs and Granite Belt, Wide Bay and Burnett and Southeast Coast Districts.

The Bureau of Meteorology has urged residents to seek a cool place, which could include a home, library, community centre or shopping centre.

'Severe heatwaves can be dangerous for many people, especially older people, babies, children, pregnant and breastfeeding women, people with medical conditions and people who are unwell,' the warning states.

'Close your windows and draw blinds, curtains or awnings early in the day to keep the heat out of your home.

'If available, use fans or airconditioners to keep cool.'

The warning comes as Mount Isa in the state's Gulf Country recorded four consecutive days above 40C this week, including 41.5C on Tuesday.

Longreach in the state's centre also reached 41.6C on Tuesday, while Richmond airport reached a whopping 42.8C the same day.

Further south, residents of the border town of Dirranbandi were forced to flee as two fast-moving grassfires closed in on Tuesday.

Emergency services were called to reports of a grass fire about 4km outside of Dirranbandi shortly after 2pm.

Some 500 residents were reportedly forced to flee the area as the Queensland Fire Department battled the blazes overnight.

By Thursday, the blaze was at an advice level and was burning within containment lines, with residents advised they could return.

A Public Safety Preservation Act emergency declaration was also revoked after power and mobile communications were restored to Hebel and Dirranbandi.

Brisbane was tipped to reach a maximum of 33C on Thursday and 34C on Friday amid possible thunderstorms before temperatures dip over the weekend.

Sydney was also forecast to top 30C on Friday before showers bring maximum temperatures down to the mid to low-20C over the weekend .

Mr Hines said early showers are forecast across NSW on Friday which should clear by about 7am, bringing a 'sunny, hot day for most of the state'.

'That will drive high fire dangers for many areas and extreme fire dangers around the Illawarra and Shoalhaven region,' Mr Hines said.

'Temperatures in Sydney could touch 30 degrees on Friday, possibly hotter than that in the western suburbs.'However storms are expected across the state's north east Friday afternoon, with Mr Hines warning of the possibility of heavy rain, damaging winds and even large hail to the Northern Rivers and Tablelands.

Melbourne was forecast to be cloudy and hovering around a maximum of 20C, with Canberra hitting 26C on Sunday and Adelaide 27C.

Mr Hines said light showers are expected across Victoria's south which should clear up by about 4pm.

'But the gusty westerlies will stick around, and that keeps a bit of a cap on the temperatures. So many places in southern Victoria just in the teens for Friday,' Mr Hines said.

Perth is forecast to reach a high of 27C over the weekend, with Hobart hitting a high of 20C on Thursday and Darwin staying at 35C.

A cold front is set to sweep Tasmania with blustery winds of up to 90km/h anticipated which could ' drive elevated fire danger '.

Friday: Partly cloudy. Medium chance of showers. The chance of a thunderstorm in the late morning and afternoon, possibly severe. Winds north to northwesterly up to 20 km/h tending north to northeasterly in the early afternoon then becoming light in the evening. Min 24 Max 33.

Saturday: Partly cloudy. Slight chance of a shower. The chance of a thunderstorm. Light winds becoming easterly up to 25 km/h in the middle of the day then becoming light in the late evening. Min 22 Max 32.

Sunday: Partly cloudy. Medium chance of showers, most likely in the evening. The chance of a thunderstorm. Light winds becoming north to northeasterly up to 25 km/h during the morning then becoming light during the evening. Min 23 Max 30.

Monday: Cloudy. High chance of showers, most likely in the afternoon and evening. The chance of a thunderstorm. Light winds becoming northerly up to 20 km/h during the morning then tending northeasterly up to 25 km/h during the day. Min 22 Max 28.

Friday: Mostly sunny. Slight chance of a shower along the coastal fringe in the early morning. Near zero chance of rain elsewhere. Winds westerly up to 25 km/h becoming light in the evening then becoming south to southwesterly up to 25 km/h in the late evening. Min 17 Max 30.

Saturday: Partly cloudy. Medium chance of showers, most likely in the morning and early afternoon. Winds southeast to southwesterly up to 25 km/h tending east to southeasterly up to 20 km/h in the morning. Min 17 Max 23.

Sunday: Cloudy. Medium chance of showers. Light winds becoming south to southeasterly up to 30 km/h during the afternoon. Min 18 Max 26.

Monday: Cloudy. Medium chance of showers, most likely in the afternoon and evening. Winds southerly 15 to 20 km/h becoming light during the morning. Min 17 Max 23.

Friday: Partly cloudy. Slight chance of a shower in the morning and early afternoon. Winds northwesterly up to 30 km/h turning west to southwesterly 25 to 40 km/h in the late morning. Min 12 Max 20.

Saturday: Partly cloudy. Light winds becoming southerly 15 to 20 km/h in the late afternoon then becoming light in the late evening. Min 10 Max 21.

Sunday: Partly cloudy. Slight chance of a shower. Light winds becoming southerly up to 25 km/h during the day then becoming light during the evening. Min 11 Max 21.

Monday: Mostly sunny. The chance of morning fog. Slight chance of a shower. Light winds becoming southerly up to 25 km/h during the afternoon then becoming light in the evening. Min 10 Max 23.

Friday: Partly cloudy. High chance of showers. The chance of a thunderstorm inland and in the north in the morning and afternoon. Winds east to southeasterly up to 20 km/h turning south to southwesterly up to 25 km/h in the late morning then becoming light in the late evening. Min 12 Max 23.

Saturday: Partly Cloudy. Winds southeasterly 20 to 30 km/h. Min 13 Max 25.

Sunday: Sunny. Winds east to southeasterly 15 to 20 km/h turning south to southwesterly 25 to 35 km/h during the morning. Min 13 Max 26.

Monday: Sunny. Winds east to southeasterly 15 to 20 km/h becoming light during the morning then becoming south to southwesterly 20 to 30 km/h during the day. Min 13 Max 27.

Friday: Medium chance of showers in the morning. Mostly sunny afternoon. Winds west to southwesterly up to 35 km/h tending south to southwesterly up to 20 km/h in the evening then becoming light in the late evening. Min 13 Max 21.

Saturday: Cloudy. Slight chance of a shower. Light winds becoming northwest to southwesterly 15 to 20 km/h in the middle of the day then becoming light in the evening. Min 9 Max 23.

Sunday: Mostly sunny. Slight chance of a shower. Winds east to southeasterly up to 20 km/h tending southeast to southwesterly during the afternoon then becoming southeasterly up to 25 km/h in the evening. Min 11 Max 26.

Monday: Partly cloudy. Medium chance of showers. Winds southeasterly up to 20 km/h turning south to southwesterly during the morning then tending south to southeasterly up to 25 km/h during the afternoon. Min 14 Max 28.

Friday: Sunny. Winds northwesterly up to 30 km/h tending westerly 25 to 40 km/h in the middle of the day then becoming light in the late evening. Min 8 Max 24.

Saturday: Mostly sunny. Light winds becoming north to northwesterly 15 to 20 km/h in the early afternoon then becoming light in the evening. Min 7 Max 25.

Sunday: Mostly sunny. Slight chance of a shower. Light winds becoming north to northeasterly up to 20 km/h during the day then turning easterly up to 25 km/h during the afternoon. Min 9 Max 27.

Monday: Partly cloudy. The chance of morning fog. Slight chance of a shower. Light winds becoming northeasterly 15 to 20 km/h during the day. Min 8 Max 26.

Friday: Partly cloudy. Medium chance of showers, most likely in the morning and early afternoon. Winds northerly up to 25 km/h turning westerly 30 to 45 km/h in the middle of the day then decreasing in the late evening. Min 10 Max 17.

Saturday: Cloudy. Slight chance of a shower. Winds northwesterly 20 to 30 km/h. Min 9 Max 18.

Sunday: Partly cloudy. Slight chance of a shower. Winds northwest to southwesterly up to 25 km/h tending south to southwesterly during the day. Min 10 Max 19.

Monday: Mostly sunny. Light winds becoming south to southeasterly 15 to 25 km/h during the afternoon then becoming light during the evening. Min 7 Max 21.

Friday: Partly cloudy. Slight chance of a shower. The chance of a thunderstorm about the Cox Peninsula. Light winds becoming northwest to northeasterly up to 20 km/h in the middle of the day then becoming light in the late afternoon. Min 26 Max 35.

Saturday: Partly cloudy. Slight chance of a shower in the morning and afternoon. Light winds becoming north to northeasterly up to 25 km/h in the middle of the day then becoming light in the evening. Min 27 Max 35.

Sunday: Mostly sunny. Light winds becoming northeasterly up to 25 km/h during the day then tending northerly during the afternoon. Min 26 Max 35.

Monday: Sunny. Light winds becoming north to northeasterly up to 25 km/h during the day then becoming light during the evening. Min 26 Max 35.