Update: At 4.40 pm, very dangerous thunderstorms were detected on the weather radar near Sydney City, Sydney Airport, Sydney Olympic Park and the Sydney Harbour Bridge, the Bureau of Meteorology warned.
These thunderstorms are moving towards the southeast, with very dangerous thunderstorms forecast to hit Maroubra, Randwick and waters off Bondi Beach by 5.10 pm.
Damaging, locally destructive winds, large, possibly giant hailstones and heavy rainfall that may lead to flash flooding are likely.
Earlier: Severe thunderstorms are expected to hit parts of the Illawarra by 3.15pm on Thursday, possibly generating damaging winds and large hailstones.
The Bureau of Meterology issued a severe weather warning for eastern NSW as "a dynamic cold front associated with a deep low pressure system in South Australia tracked east across the state".
At 2.15pm, severe thunderstorms were detected on the weather radar near the area west of Picton, the Lithgow district and the southern reaches of Lake Burragorang. These thunderstorms are moving towards the south-east.
They are forecast to affect Blackheath, Bargo and the Nattai Tablelands by 2.45pm and Wollongong, Katoomba and Penrith by 3.15pm.
While it's been a bit of a wet week, the weather is shaping up to be fine for the first weekend since restrictions have eased.
On Monday, fully vaccinated people were freed to go out and about, as long as they could prove their vaccination status.
The rainy weather since then has put a cramp on people's options to enjoy their new-found freedoms - once they'd had their fill of hitting the shops.
But just in time for the weekend, the rain is predicted to go away and the sun set to make a long-awaited appearance, paving the way for some fully-vaxxed fun.
Saturday is tipped to start off cloudy with a slight chance of a shower before the sun breaks through in the afternoon.
Sunday should be a bright sunny day with no rain in sight and winds tending west to southwesterly at 15 to 25km/h turning south to southeasterly at 15 to 20km/h during the afternoon.
Temperatures across the weekend are predicted to reach 21 degrees, perhaps not quite beach weather but still better than rain.