Hope you have a wet weather plan.

The south-east can expect a wet end to the year as an upper trough brings some instability – meaning rain, and a lot of it – to the region.

Bureau of Meteorology forecaster Adam Woods said Brisbane and the south-east could expect showers and some patchy rain from Friday afternoon, with those inland getting a thunderstorm or two.

"Tomorrow we'll see more of the very cloudy conditions and, with that, it will be a little bit cooler," he said.

"We'll also see rain in more areas, showers and thunderstorms.  We could see falls of up to 50mm across the south-east, with isolated falls around 100mm.

"Brisbane could expect to see isolated rain showers of up to 80mm.  So there is some good rainfall on the way to finish the month, especially the southern interior.  But it does start to taper off a bit as we head into the new week."

That's when that upper trough that has brought the rain begins to head north, taking its moisture with it.

Those under the rainband can expect temperatures to sit a few degrees below average – for Brisbane, that means a weekend maximum of 25 degrees.

Monday – 28, high possibility of showers, possible storm

Tuesday – 33, shower or two, possibly storm

Wednesday (New Year's Eve) – 32, shower or two

Thursday – 29, (New Year's Day) possible shower