Much of the NSW Coast is in line for a further drenching between Monday and Thursday, the Bureau of Meteorology is predicting.
Senior forecaster Jake Phillips of the Bureau said a severe weather warning for the Far South Coast would remain in place with potentially heavy rainfalls into Tuesday and the possibility of thunderstorms, damaging winds and even small hail.
"In the south east if we do see those storms develop the biggest threat is heavy rain, but we could see some small hail there as well," Mr Phillips said.
Conditions are being fuelled by a trough moving across the state through Tuesday and Wednesday, but Mr Phillips said there were some underlying factors that made the conditions stronger than usual for this time of year.
"Mid-May is a very unusual time of year to see very severe storms in NSW, but this particular case it is a combination of having a relatively significant amount of humidity around and a very powerful upper level system moving through," he said.
The Bureau said the south east and north east of the state were the main focus areas of potential storm activity, but Mr Phillips said the worst of the conditions are likely to be along the north coast.
"The concern for severe thunderstorms are particularly in the north eastern corner," he said.
The conditions could persist for a couple of days, but the Bureau is predicting that a majority of the wild weather should run through Tuesday.
"Tuesday is looking like being the peak day, however we are expecting some storms to continue into Wednesday and even Thursday, but the likelihood of severe storms will be significantly lower," Mr Phillips said.
Mr Phillips said the Bureau is urging everyone to keep an eye on forecasts and warnings in the next few days.
"We do ask people to be vigilant to look out for Bureau forecasts and warnings."