Earlier, the Bureau of Meteorology issued a severe thunderstorm warning just after 4pm for metropolitan Sydney, parts of the Hunter, Illawarra and Central Tablelands, the Riverina and Lower Western as well as the Southern Tablelands.
The severe thunderstorm warning has now been cancelled for Sydney, Wollongong and the Blue Mountains.
Suburbs earlier impacted included Campbelltown, Fairfield and Liverpool in the city’s west along with Sutherland, Engadine and Kiama in the city’s south.
Thunderstorms brought extreme winds, large hailstones and heavy rainfall that could lead to flash flooding were detected near Wollongong, Bulli, Oran Park and Albion Park.
The Bureau reported wind gusts of up to 107 km/h just before 4pm at Bellambi in the Illawarra, while 36mm of rain fell in 30 minutes near Clarence in the Blue Mountains.
Damaging winds and golf ball-sized hail were reported in parts of Western Sydney with fallen trees and powerlines forcing road closures and power outages to around 3000 homes at Denham Court.
Live Traffic Sydney reported Campbelltown Road was closed in both directions between Brooks Road and Zouch Road.
Roads have since reopened however motorists are urged to take extra care, drive to the conditions and allow for extra travel time.
In Liverpool, flooding has caused heavy traffic in both directions of Newbridge Road and Brickmakers Drive with motorists advised to avoid the area.
As severe conditions fire up across the state, the NSW SES is urging residents to keep at least eight metres away from fallen power lines, keep clear of creeks and drains and avoid walking, riding your bike or driving through flood water.