Mr Crock said a deep low pressure system moving north from the southern states near Tasmania was to blame for the upcoming cold mornings and frosty weather event.

"It's really wild weather in southern states but for Queensland it really manifests as cool and dry conditions," he said.

Mr Crock said a "real burst of wintry weather" would hit the state over the coming days as a cold front moved eastwards through south-east Queensland on Thursday night and Friday.

Where did the fog come from?

Mr Crock said Queenslanders would have seen extensive fog along the east coast from Townsville to Brisbane on Thursday morning.

"There was a bit of rain through the south-east and once that cleared overnight there was enough moisture around to form fog," he said.

"It was a little unusual to see quite so much fog right up and down the east coast as far as Townsville and particular on the Sunshine Coast and it also extended over the water through the morning hours."

But by Thursday afternoon, the bureau had issued a fire weather warning for the Darling Downs and Granite Belt as a "vigorous cold front" pushed warm conditions ahead heading east through southern Queensland pushed warm conditions ahead of it and dragged cooler weather in its wake.

"That's a combination of quite warm air, the gusty north-westerly winds and dry air as well so that creates potentially dangerous fire conditions," Mr Crock said.

"I suppose we've reached the start of the fire season now.

"It's quite an interesting combination but overall, it's related to the same weather system.

"Ahead of the trough, it's quite warm and windy but behind the trough the winds'll turn more south-westerly."

Mr Crock said maximum temperatures would gradually drop to about 20 degrees in Brisbane by Sunday with minimums of between six and eight.

"The Ekka westerlies are arriving right on time for the show starting tomorrow with west to south-westerly winds expected right through the south-east tomorrow," he said.

Colder mornings are forecast to arrive on Sunday and continue until Tuesday when the coldest morning is expected to hit.

"Those cold mornings will extend right up the coast as far as about Townsville or Ingham where temperatures will be below 10 degrees each morning through the start of next week," he said.

"We expect fairly widespread frost as well, definitely through the southern inland parts of Queensland but also extending further north up to the ranges, west of Mackay and perhaps the higher parts of the Atherton Tablelands particularly on Monday and Tuesday mornings."

No drought relief in sight

Mr Crock said the drought continued to affect southern Queensland, particularly the Granite Belt and Darling Downs regions, with minimal rainfall seen in the weather outlook.

"In terms of drought-breaking rainfall, we would need to see several months of above average rainfall to ease the really terrible conditions that we're seeing at the moment," he said.

"Unfortunately, that's not looking particularly likely in the next few months."

Mr Crock said although possible strong wind warnings were expected on Thursday and Friday, the wind would ease in time for the public holiday, Ekka Wednesday.

"So if you are heading out onto the water ... it certainly pays to check the updated forecast then but early indication is that there'll be pretty nice conditions for the holiday on Wednesday," he said.