A welcome return of sunshine will push temperatures into the 30s over the weekend in Sydney and help dry out areas of coastal NSW that copped as much as 300 millimetres of rain in a day.

The worst of the rain that soaked the mid-north and central coasts of NSW this week had passed by Friday afternoon, with the rainband breaking down into showers, Jiwon Park, a meteorologist with the Bureau of Meteorology said.

Mostly sunny days to come for Sydney and much of eastern NSW as big rain event breaks up. Credit:Leigh Henningham

Rainfall totals on Friday were unlikely to exceed the 302 millimetres of rain collected at Boonanghi, inland of Port Macquarie in the 24 hours from 9 am on Thursday. Turners' Flat and Mount Seaview were site that copped more than 240 millimetres of rain during that period.

The big rain event - often from thunderstorms within a slow-moving low pressure trough - earlier dumped more than 150 millimetres in a 24-hour period from Wednesday at places such as Dungog in the Hunter. Those falls were typically more than a month's worth of rain for this time of year.