Work crews racing to restore electricity to thousands of NSW residents may finally get a breather with Sydney's four-day run of evening storms likely to be broken on Monday.

Storm cells that formed over the Sydney's south on Sunday afternoon moved out to sea in the evening, ending a spate of violent thunderstorms that cut power to parts of the city and inundated emergency services.

The bureau issued a detailed warning for the region around Campbelltown on Sunday evening as storm cells moved across the region. Credit:BoM

The Bureau of Meteorology cancelled its severe thunderstorm alert late on Sunday evening, after warning of heavy rainfall, damaging winds and large hailstones during the day.

While the bureau was still monitoring the Sydney Basin on Sunday evening and said the city's storm streak was "not done and dusted yet", the worst of the weekend's severe weather is now over.