Southeast Qld set for second drenching

Southern Queensland will cop another drenching on Sunday, with falls likely to match those that caused flash flooding two weeks ago.

An upper level trough is expected to dump very heavy rain on Sunday, with some parts of the southeast getting as much as 150mm in just a few hours.

The Bureau of Meteorology says it could cause localised flash flooding on par with a fortnight ago.

However, conditions aren't expected to be as dangerous along the coast, where a huge east coast low combined with king tides, high winds and heavy swells.

"The rainfall will be relatively similar but were not expecting the conditions to be as bad," BOM forecaster Gordon Banks said.

The trough will enter southwest Queensland on Friday before reaching the coast on Sunday, with falls likely south of Mackay to the NSW border.

Longreach has recorded its wettest June since records began, with 138mm falling so far this month.

However, Mr Banks said it was too early to tell whether parched parts of western Queensland would receive more rain.

"These weather systems are quite dynamic ... in the last system parts of the western Darling Downs didn't get much at all," he said.

"But overall, we are expecting this to be another widespread weather event."