Source: Bureau of Meteorology

For people in Sydney area.

Issued at 8:45 pm Thursday, 14 March 2019.

The Bureau of Meteorology warns that, at 8:40 pm, severe thunderstorms were detected on the weather radar near Campbelltown, Penrith and Glenorie. These thunderstorms are moving towards the east. They are forecast to affect Hornsby, Sutherland and Liverpool by 9:10 pm and Parramatta, Sydney Airport, Sydney Olympic Park and Mona Vale by 9:40 pm.

Heavy rainfall that may lead to flash flooding and large, possibly giant hailstones are likely.

Golf-ball sized hail (4.2cm) reported at Stanhope Gardens around 6pm.

Golf-ball sized hail (4.2cm) reported at Kellyville around 6.30pm.

The State Emergency Service advises that people should:
* Move your car under cover.
* Keep clear of creeks and storm drains.
* Don't walk, ride your bike or drive through flood water.
* If you are trapped by flash flooding, seek refuge in the highest available place and ring 000 if you need rescue.
* Unplug computers and appliances.
* Avoid using the phone during the storm.
* Stay indoors away from windows, and keep children and pets indoors as well.
* For emergency help in floods and storms, ring the SES (NSW and ACT) on 132 500.