After a break from the gloomy weather on Friday Sydneysiders have been advised that a weekend of more rain and storms - possibly severe - is on the way.
A slow-moving high pressure system in the Tasman has been directing moist onshore flows into eastern NSW for more than a week.
A rain-bearing front, meanwhile, is heading eastwards, raising the prospect of storms when they meet.
"There's quite a strong upper-level system coming through and it's very unstable," said Neale Fraser, a senior forecaster for the Bureau of Meteorology, adding he would be "extremely surprised" if warnings of severe weather were not issued on Saturday for parts of NSW.
Shire residents around Engadine and Heathcote awoke to thickish fog this morning but once that had lifted temperatures reached a top of 28.7 degrees at Lucas Heights at 2.45pm. At Sydney Airport the top temperature was 27.8 at 1pm.
Friday was only the second dry day for Sydney in the past 15.
The recent wet spell has been a sharp reversal of rainfall fortunes compared with the previous three months.
Saturday should get off to a foggy if dry start in Sydney before showers and possible thunderstorms arrive in the afternoon. Those storms "might be nasty ones", Mr Fraser said.
A "little low" pressure system sitting off the coast might bring "quite a bit of rain" for Sydney on Sunday, Mr Fraser said.
On present forecasts, Sydney is set to collect 15-25 millimetres of rain on Saturday and 20-40 millimetres on Sunday.
Monthly rainfall is about twice the long-run October average.
Temperatures are tipped to reach 27 degrees on Saturday before cooling off to a top of just 19 by Sunday.
"Sunday is looking cool, cloudy, gloomy, damp and rainy, and also becoming windy," Brett Dutschke, senior forecaster at Weatherzone, said.
The low that will form offshore "is not looking like it will be intense", with the main effect likely to be to "bump up the rain", he said.