Thunderstorm forecast by the weather bureau.
Thunderstorm forecast by the weather bureau. Jasmine Burke

Severe weather bringing possibly giant hailstones

UPDATE 5.45pm: SEVERE thunderstorms are likely to produce heavy rainfall that may lead to flash flooding, large hailstones and damaging winds over the next several hours in parts of the Northern Rivers, Mid North Coast and Northern Tablelands districts.

Locations which may be affected include Grafton, Tenterfield, Tabulam, Dorrigo, Ebor and Yarrowitch.

45 mm was recorded at Doughboy Hill (near Braidwood) in the 2hrs to 4.15pm.
41 mm was observed at Big Hill (Glen Dusk near Goulburn) in the 1hr to 4.30pm.
82 mm was recorded at Murray's Flat (Wollondilly River) near Goulburn in the 2hrs to 3.30pm.
43 mm was recorded at Goulburn Water Treatment Works in the 2hrs to 2pm.

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. 

ORIGINAL STORY: NORTHERN Rivers residents have been warned to have umbrellas at the ready for the next three days as unsettled weather threatens to seriously dampen the weekend.

The Bureau of Meteorology is currently monitoring a weather system that has the potential to deliver significant rainfall to heavily populated parts of New South Wales from today.

Storms are possible over the next few days, with 45mm of rain forecast tomorrow, 30mm Saturday and another 35mm on Sunday for coastal towns including Byron Bay and Ballina.

More than 100mm will also fall in Lismore and towns further inland over the next three to four days.

The SES has warned the the intense rain will make roads and watercourses dangerous.

"The focus for the heaviest falls is expected to be the Northern Rivers area, which will see showers and thunderstorms become more frequent with some producing very heavy rain," SES said.

"North-eastern parts of the inland are also expected to see thunderstorm activity, and these storms have the potential for large hail and damaging wind as well as heavy rain.

"Heavy enough to make roads and water courses dangerous, and potential for flash flooding and damage property."

BoM's weather situation for the region reads: "A trough is forecast to linger about the northern inland whilst a coastal trough develops during Thursday.

"This coastal trough will direct a humid and unstable airmass across eastern New South Wales, generating increased showers and thunderstorm activity.

"Small scale low pressure systems may develop within the coastal trough from Thursday, which may locally enhance rainfall near the coast. During the weekend, showers and thunderstorms may extend across the northern inland as the inland trough moves towards the west."

Bureau of Meteorology NSW/ACT Manager of Weather Services, Jane Golding said rainfall in the east of the state may trigger flash flooding in some locations.

"The situation is still evolving," Ms Golding added.

Both the Regional Forecasting and Flood Warning Centres in Sydney are monitoring the situation and providing continual updates and briefings to other agencies including the State Emergency Service.

What you can do to prepare:

  • Move your car undercover and away from trees.
  • Secure or put away loose items around your house, yard and balcony.
  • Keep at least 8 metres away from fallen powerlines or objects that may be energised, such as fences.
  • Stay indoors away from windows, and keep children and pets indoors as well.
  • Do not enter floodwater.
  • Prepare your home
  • Consider pet safety during storms