The warning includes parts of the Upper Hunter including Scone as well as people in the North West Slopes and Plains, Central West Slopes and Plains, Riverina and Upper Western Forecast Districts.

Severe thunderstorms are likely to produce large hailstones and damaging winds in the warning area over the next several hours.

An earlier warning for severe thunderstorms occurring in the Mid North Coast and Northern Tablelands districts has been cancelled.

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 on 131 388, or Endeavour Energy on 131 003 or Essential Energy on 132 080, as shown on your power bill. 

* 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.