A "hard and fast" start to the severe weather season is expected to continue through the summer as NSW receives more heavy rain that could prolong the ongoing floods around the state.
"This severe weather season is not a sprint, it's a marathon," Bureau of Meteorology NSW and ACT manager Agata Imielska says.
"We've already seen severe conditions really early, a really fast and hard start to the severe weather season, and it is expected to continue with summer expected to be wetter than normal," Ms Imielska says.
November was the wettest month on record in NSW and the conditions have continued with some parts of the state set to receive their average monthly rainfall before the end of the week.
Storms are continuing to pose a threat around the state and there are multiple flood warnings active.
Severe storms were on the way Thursday afternoon for the north east corner of the state, with areas from Moree to Tamworth and Kempsey in the path of thunderstorms.
There's a risk the damaging winds, large hail and heavy rain could cause flash flooding in the afternoon and evening.
The SES conducted two flood rescues overnight, winching two people to safety after they became stranded on an island in a gorge near Armidale by rapidly rising floodwaters.
Another person was rescued from the roof of a car stuck in floodwaters at Musswellbrook.
The Bureau of Meteorology has issued a severe weather warning for heavy rain which may lead to flash flooding in the South Coast towns of Eden, Bega, Bombala and Merimbula as well as parts of Snowy Mountains.
Ms Imielska says a deepening low pressure trough "will produce some heavy rainfall, even torrential at times".
"It may not rain every single minute on Thursday and Friday but there will be some potential for that really torrential rain," Ms Imielska says.
With that rain comes the risk of flash flooding and roads being cut off, and strong winds could also uproot trees and damage properties on the south coast during Thursday afternoon and evening.
In the north of the state, a low pressure trough over inland NSW is dragging moist and tropical air from the north, fuelling severe thunderstorms on the mid north coast, northern rivers and northern tablelands.
There's also a hazardous surf warning for the Batemans coast and Eden coast, with a warning to avoid rock fishing, boating and swimming.
Flood warnings remain active around the state.
Major flooding occurring at Mungindi is expected to peak on Friday, slightly higher than the major flood level recorded during the January 2011 floods.
There's a potential roads in and out of Mungindi will be cut off "depending on how high the flood levels get", Ms Imielska says.
The Hunter River on Wednesday rose to moderate flood levels in Scone but has now eased.
Flows from the Goulburn River are expected to contribute to river level rises at Singleton and downstream from Friday.
Flood warnings are also current for the north and central west inland catchments from the Namoi to the Murrumbidgee Rivers.
Renewed river level rises and flooding is possible from across the Upper Macintyre, Gwydir, Castlereagh, Peel, Macquarie and Belubula Rivers from rainfall associated with a deepening trough extending across inland NSW.
Renewed river rises are also possible in the Lachlan, Namoi, Macquarie and Bogan Rivers where flood warnings are current.
There's a minor to major flood warning for the Lachlan River at Condobolin, Euabalong, Hillston and Booligal as well as a moderate flood warning for the Bogan River at Mudall.
Australian Associated Press
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