Potentially severe thunderstorms are firing up over parts of northern New South Wales and southern Queensland today. Locations south to about Armidale, west to about Mungindi and north to about Kingaroy are all in for a chance of a rumble today, particularly near the border and along the ranges. However, closer to the coast, thunderstorms are not as likely as a weak high pressure ridge has a stabilising effect. There are the right ingredients today for these thunderstorms to become severe, with large hail, damaging wind gusts and flash flooding. The most intense thunderstorms, known as supercells, are also a risk in these areas. A low pressure trough lying over the inland is being fed by moist northeasterly winds to generate the unstable weather. Thunderstorms remain a risk tomorrow in the south as the trough is dragged east by the a cold front to the south. While drier northwesterly winds will make activity a bit less widespread, thunderstorms still pose the threat of damaging wind gusts.