Southeast Queensland is bracing for more rain, destructive winds and flash flooding with severe thunderstorms forecast for Wednesday afternoon as an unstable weather system makes it way across the region.

Storm cells have been detected near Gympie and Noosa on the Sunshine Coast, with a warning for damaging winds and heavy rain that could lead to flash flooding.

Bureau of Meteorology (BOM) duty forecaster Rohan Smith said an unstable atmosphere was creating perfect storm conditions, with Brisbane, the Gold Coast and the Sunshine Coast the main areas of concern.

“We’ve got a south-easterly surge coming up the New South Wales coast,” Mr Smith said.

“[It is] very dynamic … going to kick off some pretty severe thunderstorms around the north-east New South Wales, south-east Queensland area.

“We’re actually looking at potentially destructive winds, which is a category above damaging, which is a gust of 125 kilometres per hour or greater.

“So quite severe thunderstorms on the cards.”

Smith said up to 100 millimetres of rain could fall in some areas, leading to flash flooding in already saturated catchments.

“If you are under a thunderstorm cell, you could get 100mm in a relatively short period of time, which is fairly concerning,” Mr Smith said.

“So flash flooding is a concern today with these storms.

Just as river levels had begun to settle, the Bureau of Meteorology also warned of more flash flooding with storms likely for Brisbane, the Gold Coast, the Sunshine Coast and Wide Bay.

The bureau is worried about the potential for a south-easterly surge making its way from NSW to spark “perfect storm” conditions.

A flood watch has been issued for people living along the Mary River catchment, including Gympie and Maryborough, with storms expected to hit late Wednesday morning and possibly push into the evening.

“The storms … are expected to be severe into the southeast so that means they could carry with them some stronger winds, a chance of hail as well as some heavier rainfall,” the BoM’s Laura Boekel said.

“We have conditions now where catchments are already very saturated, and when we see any rainfall after an event that we’ve just seen we can have some flash flooding.

“We want people to be aware…that it won’t take that much rainfall to see the impacts of the rain.”

Storms are expected to disrupt newly-appointed recovery coordinator Major General Jake Ellwood’s efforts after floods damaged more than 20,000 homes and businesses across the southeast, killing 13 people.

Inspecting flood damage along Kedron Brook at Stafford, Premier Annastacia Palaszczuk also warned of local thunderstorms hitting the region.

“Please take care if you’re out on the roads because that flash flooding can happen at any time,” she said.

She said the government would waive waste levies for all flood-related waste for 12 council areas to support the clean-up.

Major-General Ellwood praised the resilience of flood victims and the level of community support throughout the region.

Deputy Premier Steven Miles said that so far, 2534 properties had suffered moderate damage with 1797 suffering severe damage.

The Premier said the government has approached hotels that were no longer needed for Covid quarantine to provide emergency accommodation for flood victims.

More than 1200 defence force troops were cleaning up homes and businesses in Gympie, Gatton, St Lucia, Fairfield, Graceville, Rocklea, Esk, Gatton, Grantham and Goodna on Tuesday.

About 22,207 tonnes of waste – the equivalent of about 10,500 Toyota Hilux utes – has been collected so far from Brisbane residents, according to Brisbane City Council.

“This was the biggest rain event in Brisbane’s history and this is the biggest waste collection exercise in Brisbane’s history,” Lord Mayor Adrian Schrinner said.

“While the 2011 flood peak in the Brisbane River might have been higher, the area of our city that has been impacted by this disaster is significantly greater.”

The death toll rose to 13 on Monday after police found the body of a man in a car in the Condamine River, southwest of Brisbane.

Another man is missing after falling from a boat on the Brisbane River on February 26.

Deputy Premier Steven Miles said 1778 homes were severely damaged and another 2430 moderately damaged.

He said there were 17 flood mitigation projects in the pipeline, including an upgrade of Queensland’s early flood warning system.

Meanwhile, former Queensland governor Paul de Jersey will lead a three month review of Brisbane City Council’s management of the floods that inundated about 28,000 properties across the city.