Get set for a drenching, Wollongong.
The city could cop almost half its average March rainfall in one day on Thursday, with heavy rain and storms set to soak the suburbs during the afternoon and evening.
Coastal areas are expected to be the hardest hit by the forecast deluge, with the Bureau of Meteorology tipping between 20 and 60 millimetres of rain could fall in Wollongong.
Inland, Albion Park could see 15 to 40 millimetres, while the prediction for Picton is 8-25mm.
Falls could be even heavier along the coast in northern parts of the Illawarra, with Sydney potentially copping up to 70mm.
The bureau said most places along the NSW coast should see some rain on Thursday but stressed there was "still a high level of uncertainty about exactly how much, where and when it will fall".
Wollongong's average March rainfall is 133mm at its Bellambi weather station and 122.4mm at Albion Park.
The bureau said the city can expect a very-high chance of showers, possibly heavy at times, on Thursday. There's also the chance of a thunderstorm during the afternoon and evening.
The increase in shower and storm activity is due to a developing coastal trough that will direct a humid and unstable airmass across eastern NSW.
Thunderstorms are possible across most of eastern NSW today. Some storms may be severe with the biggest risk being heavy rainfall. Keep a close eye on https://t.co/Ss766eSCrL for warnings that we may issue as the day progresses. #NSWstormspic.twitter.com/GFE0QWeuJQ— Bureau of Meteorology, New South Wales (@BOM_NSW) March 13, 2019
"Small-scale low pressure systems may develop within the coastal trough from Thursday, which may locally enhance rainfall near the coast," the bureau said.
The biggest downpours are expected to be associated with thunderstorms, which will heighten the risk of flash flooding.
No warnings have been issued by the bureau, at this stage. However, it has indicated some storms may be severe, with the biggest risk being heavy rainfall.
The falls will no doubt be welcomed by many across the Illawarra after an extended spell without significant rain.
So far this month, there has been 10mm of rain at Bellambi and 9.6mm of rain in Albion Park.
The 2019 year-to-date totals are 168mm and 143mm, respectively.
The wettest day of the year so far at Bellambi was 26.8mm on February 9, while Albion Park's heaviest daily fall was 58mm on January 6.
Wet weather along the coast is still on the cards. Below is the chance of receiving any rainfall so most places should see some rain but there is a still a high level of uncertainty about exactly how much, where and when it will fall. pic.twitter.com/jEZutzfnhV— Bureau of Meteorology, New South Wales (@BOM_NSW) March 13, 2019
The showers, and the potential for storms, will linger on Friday, with up to a further 20mm possible.
At this stage, the weekend will also be wet - 4 to 10mm is possible on Saturday and up to 4mm on Sunday.
At this stage, the showers should ease on Monday.