Tennis-ball sized hail has pelted Tamworth, as persistent, heavy rain drenches large parts of NSW.
The state has been lashed by wet and windy weather all week, with Sydney and Central Coast on Monday copping a downpour that caused flash-flooding and a landslide.
Numerous severe thunderstorms have hit areas on and west of the Great Dividing Range, with the Bureau of Meteorology forecasting more for southwest NSW later on Thursday.
"We saw tennis-ball sized hail occur around the Tamworth area, and we also had large accumulations of small hail along the Northern Tablelands in places like Armadale and Guyra," bureau meteorologist Dean Narramore said.
"We also saw some pretty heavy falls on the mid-north coast, with some locations going around 50 to 70 millimetres."
The worst of that weather system has already cleared, he says, but a severe thunderstorm warning is still current for Lismore, Grafton, Coffs Harbour, Armidale, Tamworth and Taree.
Another low pressure system will hit southwest NSW later on Thursday, with the trough forecast to deepen on Friday.
That low will head east during Saturday, bringing showers to many areas, the BOM said.
"We could see some heavy falls, particularly on the central and southern coast of NSW, as that low moves out to the Tasman Sea," Mr Narramore said.
Falls of up to 100mm are expected along the coast, before conditions ease later on Sunday.
The NSW State Emergency Service is warning residents not to drive, walk or ride through floodwater in the event of flash flooding as it can contain chemicals, garbage and sewage.
"Floodwater can wash out roads that once lay underneath and just 15cm of water can start to float a small car," an SES spokesman told AAP.
