Source: Bureau of Meteorology

For people in parts of Blue Mountains/Hawkesbury, Wollondilly/Wingecarribee, Greater Wollongong and Sydney areas.

Issued at 3:11 pm Saturday, 13 December 2025.

Severe thunderstorms continue in the Blue Mountains and Illawarra this afternoon.

The Bureau of Meteorology warns that, at 3:10 pm, severe thunderstorms likely to produce heavy rainfall that may lead to flash flooding, large hailstones and damaging winds were detected near Katoomba, Blackheath and Hill Top. These thunderstorms are moving towards the east to northeast. They are forecast to affect Yerranderie, the Nattai Tablelands and Hazelbrook by 3:40 pm and Picton, Springwood and Londonderry by 4:10 pm.

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 (131 388), Endeavour Energy (131 003), Essential Energy (132 080) or Evoenergy (131 093) 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.