A major band of high-end hazardous conditions were pushing towards southern Queensland and into northern NSW on Saturday, senior Bureau of Meteorology forecaster Angus Hines warned.
"The (expected) strong winds are certainly enough to bring down branches, maybe enough to bring down entire trees," he said.
"Those trees, of course, can fall onto cars, fall onto houses and cause significant damage.
"We can also see dangerous travel conditions, flooded roads and possible isolation of streets and locations.
"There's going to be a lot of stress on the power network, particularly a chance for power outages."
Hailstones up to 8cm in diameter pounding much of the region were "absolutely possible", Mr Hines said.
The storms were expected to continue throughout Saturday evening and into Sunday in some areas.
"There's lots of places, and more importantly, lots of people, that could be impacted by severe thunderstorms later on today, and if that happens, some of the impacts could get pretty serious."
The Gold Coast, Brisbane, Sunshine Coast, Noosa Heads and inland up through the Burnett region were in the firing line, Mr Hines said.
Kingaroy, Gympie and as far north as Biloela and as far west as Roma - including the Darling Downs centres of Toowoomba, Dalby and Warwick  - were all likely in for a rough time.
In NSW, the impact zone included Tamworth, Glen Innes and across to Moree, while there was a chance some storm activity would reach major coastal communities including Port Macquarie, Coffs Harbour, Grafton, Ballina, Lismore and Byron Bay.
The dire forecast follows Thursday's fatal lightning strike on the Sunshine Coast.
Finley Bone, 21, was fatally hit by the bolt during soccer training at Cooroy. She was transported to Nambour Hospital in a critical condition, but could not be revived.
The tragedy unfolded after the Bureau of Meteorology's radar crashed as severe storms struck the region.
The bureau has faced heavy criticism after the launch of its new website on October 22, three weeks after the official beginning of storm season in Queensland, with politicians warning lives have been put at risk.
Radar images briefly failed to update on its website and the BOM Weather app.
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