Emergency services are poised for flood rescues as record-breaking downpours soak parts of south-east Queensland.

A trough extending south will bring more rain over much of central and eastern New South Wales after days of heavy rain.

The Bureau of Meteorology’s Sarah Scully said the wet weather was due to a moist onshore flow combined with a trough sitting just off the coast.

“A number of sites across south-east Queensland saw their wettest day on record for August,” she said, referring to the 24 hours to 9am on Wednesday.

“Wednesday is going to be another wet day around southern Queensland and northern NSW including Brisbane, the Gold Coast and the Sunshine Coast areas with a further 20 to 40 millimetres of rainfall forecast.”

Parts of the Queensland coast, including Yeppoon, copped a battering overnight of more than 100 millimetres in less than six hours.

Samuels Hill, north-east of Rockhampton, had 177 millimetres of rain, breaking all previous daily records for August.

Rockhampton also had a record 24-hour total for August, with 85 millimetres of rain overnight.

Forecaster Weatherzone said there had been some huge rainfall totals.

“The two-day figures have been remarkable in this event, with at least 35 Queensland weather stations recording more than 150 millimetres, while no fewer than 17 NSW weather stations have exceeded 200 millimetres,” it wrote on Wednesday.

“The good news for soaked residents of Rockhampton and nearby areas is that the unseasonable weather appears to be finished in that part of Queensland.

“The main band of rain is now located further south, with heavy rain continuing in the south-east corner of Queensland and the north-east corner of NSW today, before a gradual clearing pattern sets in.”

Another 60 millimetres of rain was forecast for Brisbane on Wednesday and up to 100 millimetres for areas bordering the city.

Flooding had already closed some roads across Brisbane’s north by early Wednesday afternoon.

Possible severe thunderstorms with heavy rain that may cause flash flooding are also forecast for K’gari, Stradbroke and Moreton islands.

Further south, about 100 millimetres of rain was expected between the NSW Tweed Coast and Coffs Harbour in 24 hours, with isolated higher falls possible.

Over the last 48 hours, our volunteers have been busy responding to 163 statewide incidents with 3 flood rescues. A further 100mm of widespread heavy rain is expected tonight, with isolated falls of up to 200mm possible.

View all warnings: https://t.co/su3fWdT1Gh pic.twitter.com/fgUOKE72GV

— NSW SES (@NSWSES) August 13, 2024

NSW State Emergency Service spokesman Andrew Edmunds said an incident management team had been set up in Lismore to co-ordinate flood rescues.

Crews had already responded to 163 incidents and three flood rescues across the state within 48 hours.

There are flood watches for parts of the northern rivers and NSW mid-north coast with localised river level rises and flash flooding likely along the Tweed, Brunswick, Richmond and Bellinger rivers.

There were minor flood warnings for the Wilsons and Orara rivers.

Many of the regions being deluged are still recovering from record flooding in early 2022.

The bulk of the wet weather system is expected to move on by Wednesday night. High humidity and widespread fog is forecast for Thursday and Friday.

Elsewhere, much of southern Australia has been basking in unseasonal spring-like weather for days. However, Weatherzone said that was about to end.

“Severe thunderstorms are possible in South Australia from Thursday afternoon and NSW, the ACT and Victoria on Friday,” it wrote.

“The most likely phenomenon is damaging winds in these storms and small hail. In NSW on Friday there is potential for a squall line to form, which could generate damaging winds across parts of the state.”

Temperatures will drop back from about 20 degrees to the mid-teens. Weatherzone said it would also be windier from Thursday to Saturday.

The rain and storms should clear later on the weekend, before another strong cold front approaches Australia’s south-east next week.

-with AAP