Torrential rain and hailstones the size of golf balls fell on parts of NSW on Friday, with forecasters warning of possible flash-flooding to come.
A severe thunderstorm warning for the mid-north coast, Northern Tablelands and parts of the Hunter Valley and North West Slopes and Plains forecast districts was in place on Friday night.
The Bureau of Meteorology (BOM) said residents in these areas could expect large hailstones, damaging winds, heavy rainfall and possible flash flooding.
The State Emergency Service (SES) spent Friday evening mopping up after the storm system moved through metropolitan Sydney.
SES spokesman Phil Campbell said the service had received 180 calls for help across the state since Friday afternoon.
"The worst of that has been Sydney, with just over 100 calls for help," he said, adding that property damage had been limited.
But the wind did bring down trees and powerlines in south and southwest Sydney, while gusts of up to 70km/h at Sydney Airport kept planes on the ground.
Sydney CBD commuters were caught in the downpour on Friday afternoon and in Wyong on the central coast 53 millimetres of rain fell in 30 minutes.
At Mount Victoria, in the Blue Mountains west of Sydney, a BOM storm-spotter reported golf ball-sized hailstones and torrential rain.
Emergency crews from Ausgrid were able to restore power to thousands of homes and businesses in Forestville and Loftus by Friday evening.
A fallen tree closed lanes of the Pacific Highway at Artarmon in the city's north and trains were suspended between Clarendon and Richmond in the city's west when power supply was affected.
Trains were also temporarily suspended between Thirroul and Waterfall on the South Coast Line as a result of heavy rain.