Towns across New South Wales are expected to break their rainfall records as parts of the state brace for major flooding.
The Bureau of Meteorology is forecasting falls of more than 150 millimetres, with communities in the North West and near the Queensland border initially expected to bear the brunt of the weather system.
"It looks like it will really ramp up during Thursday and early Friday for the north of the state north," senior BOM meteorologist Jane Golding said.
"Then as that low progresses across the south east, the Southern Ranges and South West Slopes they would see the worst of it."
The BOM says many towns in the state's north west and central west are set to receive their average November rainfall totals in the next few days.
"Gunnedah last week saw some rainfall in a day that they haven't seen on record, the closest was 10 years ago.
"Over the course of three days many locations will exceed what they normally see in November."
The rain event is expected to ease on Saturday and will be followed by cold, gusty conditions, with possible snow falling on lower ground in southern NSW.
Ms Golding said this weekend's weather was a sign of things to come this summer.
An initial flood watch has been issued for a number of NSW catchments.
Moderate to major flooding is expected on the Upper Macintyre, Gwydir, Peel, Namoi and Belubula rivers.
Minor to major flooding could also occur on the Lachlan River to Cotton's Weir and the Lower Lachlan as well as Mandagery Creek.
The State Emergency Service said it had deployed extra crews and resources ahead of this rain event.
"Additional support units and strike teams for flood rescues and stormwater damage have been pre-deployed to potential high risk areas; they are already on the road and in the air.
"The message for the communities is to be aware and prepare."
