Stormy weather is forecast for the weekend, particularly on Friday in the Northern Rivers.
The Weather Channel chief meteorologist Dick Whitaker said that a trough passing through the area, with unstable, humid and wet conditions make it possible for hailstorms to develop across the Northern Rivers, especially close to Lismore.
For Friday, the rain forecast is for 5-10mm, with heavier rain (25-50mm) for Saturday and easing by Sunday (1-5mm).
"Thunderstorms and strong wind are also possible during the weekend given the inestability brougt by the trough," Mr Whitaker said.
The same weather system has caused a severe storm warning for the Sydney Metro, Mid North Coast, Hunter and Central Tablelands this afternoon.
Large hail, strong winds and heavy rain is expected to hit areas including Taree, Cessnock, Maitland, Penrith and Parramatta over the next several hours.
Motorists and commuters are advised to exercise extreme care in storm conditions, and allow extra travel time.