A destructive storm is sweeping through central and northern Sydney with residents urged to take cover.
The weather bureau predicts large hailstones, destructive winds and heavy rain to pass southeast from Sydney's northwest from 4.45pm on Saturday.
"This is a very dangerous storm. Anyone in the north shore and Sydney city needs to take cover," Bureau of Meteorologist forecaster Adam Morgan told AAP.
Hornsby was hit hard early by storm activity with golfball-sized hailstones landing just after 4pm.
Mr Morgan said the bureau had received reports of golfball and potentially even cricket ball-sized hail in the northwest, around Hornsby and Thornleigh.
Destructive storm cells have also passed across the NSW Hunter Valley in the north and the south coast and southern highlands.
"We did have golfball-sized hail reports from the storm down in Bowral; the storms are fairly widespread," he said.
Mr Morgan added there was the potential for destructive wind gusts of more than 120km/h, large hail and heavy rainfall across Sydney and parts of the state.
"We're still expecting thunderstorms for the remainder of the afternoon, we could see some widespread activity over northeast of the state," he said.
