It’s nearly winter. So why is Brisbane bracing for storms and flash flooding?

With winter just days away, it’s hardly storm season in Brisbane. Or is it?

Storms, heavy rain and possible flash flooding are predicted to hit the city on Thursday, as a large, complex low-pressure system known as an “atmospheric river” makes its presence felt.

Weatherzone meteorologist Ben Domensino explained that an upper-level, low-pressure system would be passing – rather slowly – over south-east Queensland, destabilising the atmosphere.

“One reason this weather pattern is producing so much rain is because it is being fed by a steady feed of air from the tropics, which is also being boosted by additional moisture evaporating from the abnormally warm Tasman Sea,” he said.

“This setup is creating a conveyor belt of moisture, also known as an atmospheric river.”

Domensino said these weather systems were not uncommon in autumn and winter.

“But it’s unusual to see them stick around for so long,” he said. “This week’s system appears in no hurry to go anywhere fast.”

Bureau of Meteorology senior forecaster Christie Johnson said there was even a chance of hail on Thursday for parts of Brisbane.

However, it will fall shy of the record set in 1996, when Brisbane copped 577 millimetres in the month.

The Gold Coast is experiencing its wettest May in 17 years. In May 2009, the Gold Coast recorded 339 millimetres of rain.

Already this month, the region has received 271 millimetres.

The unusual weather system was predicted to move offshore by Friday afternoon, making way for a sunny reprieve on Saturday morning that should last well into next week, giving residents a chance to dry out and finally hang some washing on the outside line.

“We’ll definitely get a chance to dry out over the weekend with lots of sunshine forecast,” Johnson said.

Sunshine is forecast for Saturday, Sunday, Monday and Tuesday, with temperatures maxing out at a pleasant 24 degrees.

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