A low-pressure weather system is dumping widespread rain, with severe thunderstorm activity forecasted to escalate across much of the state today.
Heavy rain, large hail, and damaging wind gusts are predicted, particularly in the west, where there may also be giant hail more than five centimetres in diameter, and destructive winds reach more than 120 kilometres an hour.
NSW SES is warning that the rainfall may cause flash flooding along rivers in parts of Sydney Metro, Illawarra, South Coast, the Central West, and southwest of the state.
According to the Bureau of Meteorology, Porters Creek Dam, near Milton, recorded 350 millimetres of rain in the 24 hours to 9am on Wednesday.
Sassafras recorded 231mm, while nearby Nerriga received 106mm.
Foxground near Berry recorded 164mm, Nowra 110mm, and Braidwood 97mm.
Bega received a much-needed drop of 105mm on the Far South Coast, while Bodalla recorded 133mm.
Areas such as Cooma and Bombala only managed about 20mm each.
Numbaa dairy farmer Tim Cochrane said the rain was very welcome.
"We planted corn in mid-October, so it is good timing combined with the humid weather," he said.
"The dryland crop was lacking moisture, so it's perfect timing after receiving no spring rain."
NSW SES has conducted two flood rescues on the South Coast this morning.
One incident was at South Nowra, where two people were rescued from their car while others were rescued from a home at St Georges Basin.
A warning has been issued for Lake Conjola, where water levels have risen significantly overnight, causing low-lying areas of Lake Conjola to be impacted by floodwaters.
Significant falls of rain "filled in the gaps" in the Central West and southwest of the state while northern regions who danced with delight last week watched the wide front of thunderstorms slide in a southeasterly pattern.
Forbes district stock agent Luke Whitty, Kevin Miller Whitty Lennon and Co, said the town centre measured 95mm, the airport recorded 92mm and where he lived, 10 kilometres away, measured 85mm.
"This is the rain we needed. We got nothing last week, and these storms have been filling in areas where no rain fell," Mr Whitty said.
"Around the immediate Forbes district, there was 85 to 95mm, but if you went 40 to 50km away, the falls were around 40 to 50mm.
"It's a big kick today, and all we need are the markets to keep heading north."
With harvest predominantly completed in the Lachlan area and only irrigated crops in the ground, recent rainfall won't significantly impact the area in the short term.
Parkes received 52.6mm in the 24 hours to 9am on Wednesday and 88.8mm since November 26, while Forbes received close to 100mm.
YellCo Ag agronomist Peter Yelland said the rain would give growers the confidence to plan their programs for the 2024 winter season.
"In the short term, this rain won't change much," Mr Yelland said.
"But it will build up that soil moisture profile to go into next year.
"It gives people a little bit of confidence because the lemon was squeezed completely dry.
"Coming out of this season up until 10 days ago, we had absolutely zero moisture in the profile.
"This rain will give people a little confidence to start to make plans for next year under a normal planting.
"When you've got no subsoil moisture for a crop like canola, we know historically its reliability crashes.
"So it might just reinforce what people are considering doing in terms of setting up their rotations or areas for next season."
Agronomist at Agriwest Parkes, Seb Weber, said while not much had gone in the ground in the way of summer crops for the area, growers would try to maximise the soil moisture for next year's winter programs.
"Before the rain, the fallows were pretty clean, but growers will now be expecting some weeds to come up," he said.
"They will react to this and look to spray these out and keep as much water in the soil for next year's crop.
"Dryland growers didn't bank on it raining this much and didn't plant summer crops because of that."
Menindee in the Far West recorded 65mm.
Menindee resident Graham McCrabb said the overnight fall was the most significant in two months of almost no rain.
"It's awesome," Mr McCrabb said.
"It's been a long time since we've had that sort of rain.
"The growth in pastures will now get a start, and we'll see a difference within two to three weeks."
Stacey Callinan, Dust N Rain Dorpers, Pooncarrie, recorded less significant falls, but with 20 to 60mm last Thursday, the overnight rain was a good follow-up.
"We went for a drive on Sunday, and the were green shoots in the spear grass already," she said. "It's not a huge amount, but it's a good follow-up," she said.
South of Deniliquin in the Riverina, 135mm of rain was recorded, where it appears the cloudburst was over the south of the town and airport rather than in the north.
Elders Mildura's livestock manager, Kelvin Fitzgerald, described the rain as "magnificent".
He said his brother Joel Fitzgerald on Carinya Station south of Ivanhoe had recorded 100mm, as had Edward Rees at Paneena, Ivanhoe and Tom Palmer, Girrawheen Pastoral Company, Ivanhoe.
"There have been falls of 80mm at Swan Hill, 70mm at Springwood, while Anabranch north of Wentworth, had 25mm," Mr Fitzgerald said.
"It's filled dams, run water and will get some green feed going."
Matt Nathan, Fallonville, Deniliquin, 15km west of Deniliquin, recorded 67mm of rain.
While there was no damage to any infrastructure, there were large volumes of water in lakes across his property.
He has no crops, only stock on native pasture, which he said "are still green and will respond to this rain".
However, according to Erin King, childcare centres and schools were closed at Deniliquin on Wednesday, and water had damaged offices in the town centre.
"Most farmers are halfway through the stripping, so this has just wrecked most crops," Mrs King said.
"It was mainly Moulamein Wakool road that got the big 130mm."
Laurie and Pam Beer, 24km northeast of Deniliquin, run an 800-hectare mixed farming operation consisting of a self-replacing Poll Merino flock, cereal crops and rice paddies, receiving 26mm overnight.
"What we've had here will probably do as much good as harm," Mr Beer said.
"A lot of wheat crops around are not harvested yet, so the first rains are probably not too bad, but if we get follow-up rain, that will do a lot of damage.
"What we haven't stripped will be ok. I don't expect this will damage it too much, but I don't know anyone who's had 100mm on it; that could be another story.
"We wouldn't be any more than a third on the way into stripping, and I don't think there would be many people that would be too much more into it, some maybe halfway through, it's just in the last week where they have got into it fair dinkum."
- By Simon Chamberlain, Helen DeCosta, Denis Howard, Stephen Burns and Hayley Warden.