A severe thunderstorm warning has been issued for parts of the Hunter, with heavy rain and possible hail set to hit on Christmas eve.
Dark storm clouds have formed over Newcastle, where a thunderstorm is expected, while heavier storms are predicted for the Upper Hunter.
The Bureau of Meteorology said an upper trough was providing support for thunderstorm activity on Sunday morning in a moist and unstable airmass.
"Severe thunderstorms are likely to produce large hailstones, heavy rainfall that may lead to flash flooding and damaging winds," the bureau said in a warning at 9am on December 24.
Locations which may be affected include Tenterfield, Liston, Murrurundi and Quirindi.
For emergency help in floods and storms, ring the SES (NSW and ACT) on 132 500.
