“In the next couple of days from Wednesday onwards, there will be higher accumulated totals over the coastal range and particularly over the firegrounds.”
Mr Shabren said the high rainfall was also likely to result in runoff into waterways and dams. Rainfall on dry burn areas also raised the risk of potentially dangerous landslips.
“There will be intense bursts of rainfall. It can be tricky with dry burnt areas because landslips are possible,” he said.
“This rainfall will be heavy and there will be some isolated falls as well and thunderstorm activity.” trough of local pressure – as it deepens widespread heavy rainfall.
The NSW Government has contingency plans to address the possibility of the ash from the recent bushfires being washed into water courses and dams. It has installed “silt curtains” and floating barriers protect dams across the state.
Erratic winds might also threaten property damage.
Mr Shabren said weather forecasts were subject to changing later in the week.
The NSW SES is warning that severe thunderstorm threaten to produce “damaging winds, heavy rainfall that may lead to flash flooding and large hailstones”.
Locations which may be affected include Coffs Harbour, Port Macquarie, Taree, Woolgoolga, Sawtell and Dorrigo.
According to the NSW Incident Alerts Facebook page, widespread falls of 50-100mm of rain are forecast along the entire coastline as well as the northern inland over the coming 10 days.
“Parts of the coast could see in excess of 200mm,” it says.
“The NSW SES advises people to factor in enough time for actions that may take longer to complete in preparation which include moving animals away from low lying areas that are prone to flooding as well as moving pumps away from swollen creeks.”
Rural Fire Service spokesman Greg Allan said rain was always welcome but it could also stop backburning activity and was unlikely to put all all 65 fires currently burning.
“It would need a lot of continuous rain across the entirety of all firegrounds for all fires to be extinguished,” he said. “Fires burning across hundreds of thousands of hectares.
“When there is a lot of rain, safety can be compromised with falling trees and landslips.
“Our crews will need to take that into account.”
Anna Patty is Workplace Editor for The Sydney Morning Herald. She is a former Education Editor, State Political Reporter and Health Reporter.