Source: Bureau of Meteorology

For people in parts of Blue Mountains/Hawkesbury, Gosford/Wyong and Sydney areas.

Issued at 3:29 pm Tuesday, 26 December 2023.

The Bureau of Meteorology warns that, at 3:25 pm, a VERY DANGEROUS THUNDERSTORM likely to produce GIANT HAILSTONES, damaging winds and heavy rainfall that may lead to flash flooding was detected near Maroota and Wisemans Ferry. This thunderstorm is moving towards the east. It is forecast to affect Mount White, Spencer and Brooklyn by 3:55 pm and Woy Woy by 4:25 pm.
Other severe thunderstorms likely to produce large hailstones, damaging winds and heavy
rainfall that may lead to flash flooding were detected. Thunderstorms are moving towards the south to southeast. They are forecast to affect Calga, Wyong and Tuggerah by 3:55 pm and Dee Why, Manly and Mona Vale by 4:25 pm.

4 to 5 cm hailstones were reported in the Rutherford and Maitland area between at 1:30 and 2:00 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.