Snow has fallen in parts of northern New South Wales, while other areas of the state are being battered by rain and wind.

Uralla and Guyra, on the Northern Tablelands west of Coffs Harbour saw surprise blizzards.

Daytime temperatures in the area are hovering around one degree but dropped to as low as minus three overnight.

Thick flakes were seen a falling from the sky and covering the ground in both towns.

Meanwhile, Sydney and surrounds continue to be battered by another day of rain with between 30mm to 80mm possible.

A significant weather alert has been announced for the Mid North Coast, Hunter North West Slopes and Plains, Northern Tablelands, and Central Tablelands Forecast Districts due to ongoing rain and storms from a low-pressure system.

Damaging wind gusts of around 90 km/h are likely to develop on the coast from early this afternoon for coastal areas, the Bureau of Meteorology said.

Strong winds are expected to continue into Sunday. 

Heavy rainfall could lead to flash flooding this afternoon in inland parts of the Hunter, Mid North Coast and Northern Tablelands.

NSW SES Assistant Commissioner Nicole Hogan urged people in the impacted areas to be smart and act wisely around floodwaters.

“Due to the forecast rainfall, some roads could become flooded and impassable, so above all, never drive through floodwaters,” Hogan said.

“If the road is flooded, stop, turn around and find another way.”

Very strong marine winds are expected along the entire east coast, so surfing or going out to sea on a boat is not advised. 

The storm is stretching down to Wollongong, Newcastle and the Central Coast.

Thunderstorms and lightning have already hit across much of Sydney, Gosford and parts of Newcastle.

The wet weather is expected to stick around all day, before moving off the NSW Coast on Sunday afternoon.

However rain will continue into next week.

Residents are urged to keep an eye out for severe weather updates and flash flooding warnings.