Staying in Sydney and take care if you’re heading away for the long weekend.
A wet weather system rolling across the state’s mid-north coast and parts of the Hunter is set to intensify, including including Grafton, Coffs Harbour, Port Macquarie, Taree, Kempsey, Woolgoolga, Sawtell, Dorrigo, Seal Rocks, Bulahdelah, Wingham and Nelson Bay.
The heavy rain may lead to flash flooding.
Double demerits are also in force.
Rainfall totals in excess of 100mm in 24 hours are expected in some areas on Friday night, particularly southern parts of the Northern Rivers, with that estimate even going higher depending on thunderstorms.
Minor to moderate flooding has also been forecast from Saturday onwards for the Orara, Bellinger and Kalang, Nambucca Valley and Hastings Valley river systems.
"We're already seeing some rainfall focused around southern parts of the mid north coast and we are expecting that to intensify into this evening and become more widespread," BoM forecaster Rebecca Kamitakahara told AAP on Friday morning.
"That's all been generated by a trough off the NSW coast which is starting to deepen."
There is some "uncertainty" over how the system will develop into the night, she said.
The Macquarie Coast and Hunter Coast are warned to brace for strong onshore winds on Friday, set to blow their way up to the Byron Coast on Saturday.