It could be the best present of all for some of Queensland's farmers with heavy monsoonal rain to drench thirsty parts of the state tomorrow.

The Central Highlands, Central Queensland, Capricornia, Central West and parts of North Queensland are in line for the heavy falls to peak on Christmas Day.

Sky News Weather Channel's Chief Meteorologist Tom Saunders predicting 100mm in isolated falls on Christmas Day.

BOM Meteorologist Livio Regano said it could be the 'best Christmas present' ever for those places who rely on rain for their livelihoods.

"It's a monsoonal influence, so there is an inland trough which isn't just a garden variety trough, it is a monsoon trough," Mr Regano said.

"It's drawing air from across the other side of the equator all the way into Queensland, it is really thickly moisture laden, its unstable and has the capacity to produce heavy falls, all it needs is an uplift mechanism."
And it has one.

A south-easterly change came through Queensland yesterday and has created an tunnel of unstable air from the tropics into Central Queensland.

"Christmas Day is the peak, tomorrow is the heaviest falls where we could get 100mm," he said.

"It's cause for celebration, it might not be the best Christmas celebration but even though their outdoor plans might be ruined I think they'll be pretty happy with the rain and the temperatures a bit more comfortable."

The southeast will have some isolated showers and be cooler than usual, with an overcast day expected tomorrow.

Over the last 24 hours around 70mm fell in spots around Mackay and up near Normanby in Far North Queensland 139mm fell at Hann River.

Originally published as Monsoonal rains to deliver Christmas Day drenching