Sydney gardens are expected to get relief from the dry spell on Friday as long-awaited showers and possibly thunderstorms arrive, the weather bureau predicts.

For the rest of Thursday, Sydney can expect two to six millimetres of rain with the possibility of a dry thunderstorm in the afternoon.

Upper Central NSW is set to receive a battering this afternoon, as heavy rainfall, large hailstones and dangerous winds sweep over the region. Photo by Nick Moir.

Light rainfall could continue into the night, with heavier falls and hail expected to continue into Sunday.