• The Bureau of Meteorology forecasts over 100mm of rain for parts of NSW and warns of flash flooding. (AAP)
Sydney and parts of NSW have been battered by a thunderstorm which has left three women recovering from lightning strike and hundreds of homes damaged.
Source:
AAP
18 Feb 2017 - 8:04 PM  UPDATED 18 Feb 2017 - 8:04 PM

Three women have been struck by lightning and widespread damage has been inflicted by a hailstorm that swept through Sydney and parts of NSW.

The storm cell hit the city's northwest about 4pm on Saturday, depositing golf ball- and even cricket ball-sized hailstones accompanied by wild winds and heavy rain.

Rouse Hill, Kellyville and St Ives bore the brunt, with the hail damaging roofs, smashing car windows and bringing down trees.

A retirement village in Glenhaven, near Kellyville, copped some of the worst of the battering, with "significant damage" to the roof, the NSW State Emergency Service said.

Meanwhile three woman in their 60s were taken to hospital after they were struck by lightning in Bowral, in the state's southern highlands.

SES volunteers have been stretched thin, with more than 630 calls for help relating to leaking roofs, hail damage, broken skylights and downed trees.

"We've got hundreds of volunteers out at the moment, they've been working hard since yesterday's storms," SES spokeswoman Sue Pritchard told AAP.

The phones had been ringing off the hook, she said, with at least 100 calls still banked up by 7pm.

'We're asking people to be patient because we can only take so many calls we can take at one time."

Golfball-sized hailstones also swept through Hornsby and Thornleigh, while destructive storms passed across the Hunter Valley to Sydney's north as well as the south coast and southern highlands.

The mop-up is expected to continue through the night, with replacements coming through for SES crews working since Friday's electrical storms.