The Bureau of Meteorology has forecast a "likely" chance of severe thunderstorms on Monday in the Riverina east of Narrandera and in the South West Slopes region.
Severe thunderstorms were "possible" in the Riverina around Griffith and Hay.
A forecast on Sunday stated that thunderstorms are likely to continue overnight into Monday across southern and central parts of inland NSW and then becoming more active across the east and south during Monday afternoon and evening.
Severe thunderstorms are possible for much of NSW, with damaging winds, large hail and heavy rainfall all a concern.
Wagga's weather forecast for Monday was a high of 26 degrees with a very high 90 per cent chance of showers with a thunderstorm likely, possibly in a severe form.
The Bureau has also issued a severe thunderstorm warning for damaging winds, large hailstones and heavy rainfall for people in Snowy Mountains and parts of Central West Slopes and Plains, Riverina, Lower Western, Upper Western and Australian Capital Territory Forecast Districts.
A broad trough of low pressure lies over inland New South Wales, with another trough along the coast. Humid air feeding into these systems will bring thunderstorms across parts of the state.
Severe thunderstorms are likely to produce damaging winds and large hailstones over the next several hours from Sunday afternoon in parts of the Central West Slopes and Plains, Riverina, Lower Western and Upper Western districts.
Locations which may be affected include Albury, Deniliquin, Griffith, Narrandera, Cobar and Darlington Point.
Severe thunderstorms are likely to produce heavy rainfall that may lead to flash flooding over the next several hours in the Snowy Mountains and parts of the Australian Capital Territory districts. Locations which may be affected include Cooma, Cabramurra, Selwyn, Bredbo, Adaminaby and Nimmitabel.
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.