Source: Bureau of Meteorology

For people in Greater Wollongong and parts of Wollondilly/Wingecarribee areas.

Issued at 9:57 pm Friday, 12 January 2018.

The Bureau of Meteorology warns that, at 10:00 pm, severe thunderstorms were detected on the weather radar near Bowral, Bundanoon and Robertson. These thunderstorms are moving towards the east to southeast. They are forecast to affect Wollongong, Kiama and Picton by 10:30 pm and Helensburgh, Stanwell Park and waters off Thirroul by 11:00 pm.

Heavy rainfall that may lead to flash flooding, large hailstones and damaging winds are likely.

The State Emergency Service advises that people should:
* Move your car under cover or away from trees.
* Secure or put away loose items around your house, yard and balcony.
* Keep at least 8 metres away from fallen power lines or objects that may be energised, such as fences.
* Report fallen power lines to either Ausgrid on 131 388, or Endeavour Energy on 131 003 or Essential Energy on 132 080, as shown on your power bill.
* 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.