On Saturday, a broad inland trough stretched across the central inland region, dividing the state in two, with the eastern part facing wet conditions, while the west stayed fairly dry.
Parts of the Penrith, Bowral, Campbelltown, Orange, Mudgee, Bathurst, Katoomba and Goulburn faced severe thunderstorm conditions and saw damaging winds, heavy rainfall and hail.
Other parts of the state, including Blaxland, Badgerys Creek, Horsley Park, Parramatta, Blacktown, Londonderry, Penrith and Riverstone are expected to see thunderstorms by 5.25pm.
“Large, possibly giant hailstones, damaging winds and heavy rainfall that may lead to flash flooding are likely,” a warning on the bureau’s website read.
Meanwhile, a warm front will bring temperatures into the low 40s for some parts of the western Riverina region on Sunday and Monday, which will see a heightened fire danger.
A Total Fire Ban has been declared for the eastern and southern Riverina regions on Sunday due to forecast hot and windy conditions.
As the passage passes on Sunday and Monday, temperatures are expected to drop and make way for possible storms across a broad area of the state.