More thunderstorms are sweeping across the state from the west, with the Bureau of Meteorology issuing a severe thunderstorm warning for damaging winds for the entire Northern Rivers, including Lismore, Casino, Ballina, Kyogle, Byron Bay.

The BoM has shifted its warning in the last hour to include all of the Northern Rivers, after initially issuing a damaging wind warning for Casino and Yamba.

The BoM say that a cold front moving through NSW is combining with an upper-level trough and an unstable airmass to produce further severe thunderstorms this evening.

The thunderstorms are likely to produce damaging in the Northern Rivers warning area over the next several hours. Locations which may be affected include Lismore, Grafton, Tenterfield, Tweed Heads, Murwillumbah and Byron Bay.

Examples of wind gusts that have been recorded earlier this afternoon are:

• 98 km/h wind gust recorded at Merriwa at 6:04 pm.
• 96 km/h wind gust recorded at Taree Airport at 4:08 pm.
• 96 km/h wind gust recorded at Murrurundi Gap at 3:03 pm.
• 119 km/h wind gust recorded at Nobby's Head at 2:12 pm.
• 100 km/h wind gust recorded at Maitland Airport at 2:03 pm.
• 3.5 cm hail reported at Denman at around 1:20 pm.
• 109 km/h wind gust recorded at Dubbo at 12:25 pm.
• 111 km/h wind gust recorded at Trangie at 12:01 pm.
• 110 km/h wind gust recorded at Orange at 11:52 am.
• 98 km/h wind gust recorded at Parkes at 11:02 am.

Safety advice

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.

* Trees that have been damaged by fire are likely to be more unstable and more likely to fall.

* Unplug computers and appliances.

* Avoid using the phone during the storm.

* Stay indoors away from windows, and keep children and pets indoors as well.

* Stay vigilant and monitor conditions. Note that the landscape may have changed following bushfires.

* For emergency help in floods and storms, ring the SES (NSW and ACT) on 132 500.

Warnings are also available through TV and Radio broadcasts, the Bureau's website at www.bom.gov.au , or by calling 1300 659 210. The Bureau and State Emergency Service would appreciate warnings being broadcast regularly.

The next warning is due to be issued by 10:40 pm.