Storms, hail hits NSW Blue Mountains

Hailstones bigger than golf balls have hit the Blue Mountains as severe thunderstorms sweep across parts of NSW.

Damaging winds, hailstones and severe thunderstorms were predicted to hit Sydney's far west as well as the Hunter, Illawarra and Central Tablelands regions on Thursday evening.

Photos on social media show large hailstones raining on residents in the Blue Mountains, described as "sheets of ice" by local Shannon King on Twitter.

"I have some small dents in my car but animals (are) ok," she said.

The storms come after wild weather lashed Sydney's west and south on Wednesday evening.

More than 20,000 homes lost power when heavy rainfall, damaging winds and lightning rolled through after 7pm.

A Bringelly family was forced to leave their home when their roof collapsed, while another piece of roof blew onto train tracks at Mount Druitt.