A severe thunderstorm warning for large hailstones, heavy rainfall and damaging winds has been issued for the Hunter.
The Bureau of Meteorology listed Scone and Cessnock as places that may be affected, along with areas including the Mid North Coast, the Central Tablelands, North West Slopes and Plains and Northern Tablelands.
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 clear of fallen power lines.
* 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.
SES: 132 500.