A flood watch has been issued for coastal catchments from Cairns to Gladstone extending inland to the Burdekin and Fitzroy catchments.

BoM Weather Services Manager, Richard Wardle, said the flood watches come ahead of a trough and associated heavy rainfall forecast from late Wednesday.

"Widespread rainfall totals in the range of 100-200mm can be expected with rainfall decreasing as it moves south," he said. "Rain and isolated storms will spread to the southeast coastal districts including Brisbane on Friday, with decreasing rainfall in the 25-75mm range. Isolated showers and storms are possible on Saturday.”

A flood watch has also been issued for a second trough forecast to move through the southwest Channel Country and Western Queensland, bringing with it the chance of showers and thunderstorms for inland areas on Thursday and Friday.

"The most likely area for storms will be near and to the east of this slow moving surface trough, from Cloncurry south to Cunnamulla.”

“Some of these storms may be severe," he said.

"While isolated heavier falls associated with thunderstorms are possible, rainfall in the southwest will be considerably lower – in the 30 to 50mm range."

Mount Isa is expecting showers and possible storms Thursday and possible showers Friday.