Source: Bureau of Meteorology

For people in North West Slopes and Plains and parts of Northern Rivers, Hunter, Central Tablelands, Central West Slopes and Plains, Upper Western and Northern Tablelands Forecast Districts.

Issued at 7:32 pm Wednesday, 20 December 2023.
Severe thunderstorms have also developed over the Northern Rivers and are approaching Lismore.

Weather Situation: A surface trough extends through the centre of the state and has caused the development of severe thunderstorms. Thunderstorms are moving to the east and northeast and will persist into the evening.

Severe thunderstorms are likely to produce large hailstones and heavy rainfall that may lead to flash flooding over the next several hours in the North West Slopes and Plains and parts of the Hunter, Central Tablelands, Central West Slopes and Plains and Upper Western districts. Locations which may be affected include Gunnedah, Moree, Narrabri, Mungindi, Coonabarabran and Coonamble.

Severe thunderstorms are likely to produce heavy rainfall that may lead to flash flooding over the next several hours in parts of the Northern Rivers and Northern Tablelands districts.

Locations which may be affected include Lismore, Casino, Kyogle, Coraki, Whiporie and Woodburn.

44.8 mm was recorded in the 30 minutes to 7:20 pm at Dairy Flat.
50.2 mm was recorded in the 2 hours to 6:00 pm at Gilgandra.
40.0 mm was recorded in the 60 minutes to 5:45 pm at Dubbo Airport.

The State Emergency Service advises that people should:
* Move your car under cover.
* 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.
* Be aware that run-off from rainfall in fire affected areas may behave differently and be more rapid. It may also contain debris such as ash, soil, trees and rocks.
* After bushfires, heavy rain and the loss of foliage can make the ground soft and heavy, leading to a greater chance of landslides.
* 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.