Source: Bureau of Meteorology

For people in parts of Gosford/Wyong and Sydney areas.

Issued at 4:20 pm Sunday, 18 October 2020.

The Bureau of Meteorology warns that, at 4:25 pm, severe thunderstorms were detected on the weather radar near Hornsby and Glenorie. These thunderstorms are moving towards the northeast. They are forecast to affect Frenchs Forest, Gordon and Terrey Hills by 4:55 pm and Calga, Woy Woy and Mona Vale by 5:25 pm.

Large hailstones and heavy rainfall that may lead to flash flooding are possible.

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.