SEVERE, slow moving thunderstorms are expected to develop over the Tweed tomorrow, but the shire is expected to be spared the worst of potential supercell storms predicted for the wider region.

A southerly change moving up the New South Wales North Coast from tomorrow morning is forecast to merge with northerly winds to create thunderstorms as they meet near the Queensland border.

Weatherzone meteorologist Rob Sharpe said while thunderstorms could affect the border region, the possibility of supercells forming in the area was relatively low.

"There's a good chance these storms will be somewhere between Yamba and Brisbane, but there should be some thunderstorms fairly close to the coast between those locations. Most likely between Byron and Tweed,” Mr Sharpe said.

"If storms do happen on Tweed, they'll be slow moving thunderstorms, but it's only a chance.

"It looks like a low chance for most areas along that stretch of coast and the vast majority will remain dry.”

Mr Sharpe said the areas most likely to be affected by severe thunderstorms and supercell activity were those located further west along the ranges.

While supercells are a possibility, severe thunderstorms were more likely, he said.

"We're very likely to see thunderstorms occurring inland along ranges tomorrow and we could see supercells, but the wind regime isn't that conducive to super cells,” Mr Sharpe said.

"There's a significant chance of flash flooding for the hinterland and areas from the Northern Tablelands, stretching as far north as Gayndah (west of the Sunshine Coast).”

Mr Sharpe said while the Tweed would likely be spared tomorrow's severe storms, there was a strong chance severe thunderstorms would affect the region again on Monday.

• Information on how residents can prepare for severe weather can be obtained by visiting the NSW SES website www.ses.nsw.gov.au
• For emergency assistance in storms and floods call the NSW SES on 132 500 and in life threatening situations call triple zero.
• For emergency help in floods and storms, call NSW SES on 132 500.