A SEVERE thunderstorm warning has been issued for New South Wales with areas likely to be affected including Grafton and Coffs Harbour.
The weather bureau said the storms were likely to produce large hailstones and heavy rainfall that may lead to flash flooding and damaging winds in the warning area.
Locations which may be affected include Grafton, Coffs Harbour, Port Macquarie, Tamworth, Bourke and Lightning Ridge.
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.
* For emergency help in floods and storms, ring the SES (NSW and ACT) on 132 500.
The next warning is due to be issued by 4:35 pm.
If severe thunderstorms develop in Sydney Newcastle Wollongong or surrounding areas, a more detailed Severe Thunderstorm Warning will be issued to people in this area.