Intense rain and thunderstorms will develop across Queensland and northeastern New South Wales on Thursday, storms have potential to become severe.
Flash flooding and damaging winds are likely and large hail cannot be ruled out.
There's potential for more than 30mm in under an hour, enough to get rivers and creeks flowing fast and for water to briefly cover roads. Storms also have the potential to produce 100km/h wind gusts. strong enough to bring down trees and power lines and to unroof buildings.
When storms are just about done, large hail becomes a risk.
Storms will be most intense north of about Grafton and Tenterfield in NSW and east of about Miles and Clermont in Queensland. It includes Brisbane, the Sunshine and Gold coasts, the Darling Downs, Lismore and Byron Bay.
This is the area where the atmosphere will be most dynamic. Warm, moist air from the north will be mixing with much colder, drier air from the south.
The low pressure trough causing this rain and storms is due to take it all offshore during Thursday night.
On Friday and over the weekend, blue skies will dominate.
© Weatherzone 2012
16:28 EDT Hail is caused when raindrops are lifted up into the atmosphere during a thunderstorm and then supercooled by temperatures below freezing, turning them into ice balls.