The SES is carrying out flood rescues and has responded to more than 150 incidents as heavy rain lashes parts of New South Wales, moving towards Sydney.

The Bureau of Meteorology said up to 250 millimetres of rain was possible in some areas on Thursday as a surface trough extending from the Illawarra region into the Tasman Sea deepened in response to an upper low over central NSW.

“Heavy rainfall, which may lead to flash flooding, is forecast for the Illawarra and parts of the south coast, Southern and Central Tablelands, and metropolitan districts today and through Friday afternoon,” the weather bureau warned on Thursday.

“Scattered six-hourly rainfall totals between 50-100 millimetres are likely with isolated totals around 150 millimetres possible. Scattered 24-hourly rainfall totals between 100-150 millimetres are likely, with isolated totals around 250 millimetres possible.”

By 3pm on Thursday, the NSW SES said there had been nine flood rescues, including seven in the Illawarra and Shoalhaven areas, and 156 incidents in the past 24 hours.

“There were four flood rescues in Nowra early this morning, [and] 13 active flood warnings,” it said on X.

Earlier, south-east deputy zone commander Barry Griffiths said pleaded with people to “remain cognisant of the rainfall that’s moving through and just adapt to that, (so we can) get through this without too much trouble.”

Heavy rain continues today in #NSW.

A Severe Weather Warning for heavy rainfall is current for the #Illawarra & parts of the #Sydney Metro, South Coast, Central & #SouthernTablelands.

Flood warnings and flood watches are current.

Latest: https://t.co/4W35o8i7wJ pic.twitter.com/pUO1s21GJ1

— Bureau of Meteorology, Australia (@BOM_au) June 6, 2024

The 48-hour deluge follows heavy rain in the Illawarra throughout Wednesday. Forecaster Weatherzone said nearly 200 millimetres fell in the region in the 24 hours to 9am on Thursday.

“And it’s not over yet. The satellite images below show relentless rain streaming into the Illawarra and south coast regions on Thursday morning,” it wrote.

The rain was expected to spread north into the Warragamba catchment, and as far as Campbelltown, on Thursday.

WaterNSW issued an alert for the Warragamba Dam on Wednesday, warning it is likely to spill on Thursday or Friday.

“Rain will also increase in the Sydney region on Thursday, with 30-60 millimetres expected to fall in the 24 hours to 9am on Friday,” Weatherzone said.

“Over the Warragamba Dam catchment, 60-80 millimetres is likely, with 100-150 millimetres possible. As of Thursday morning, the Warragamba Dam is at 98 per cent capacity, meaning this rainfall has the potential to spill the dam in the Napean River.”

With heavy rain falling across the coast, #RFS crews are assisting the @NSWSES with flood & storm damage. Earlier, crews responded to reports of a trapped motorist after they attempted to drive through flood waters. The driver was successfully rescued by a SES flood rescue team. pic.twitter.com/H24aCDgvyo

— NSW RFS (@NSWRFS) June 6, 2024

The BoM has issued a flood watch for parts of Sydney, the central and south coasts and Illawarra and South Coast. It also has flood warnings for numerous areas.

Locations most likely to be affected include Wollongong, Nowra, Bowral, Campbelltown, Ulladulla, Jenolan Caves, Oberon, Taralga and Nerriga.

Rivers at most risk of flood are in the St Georges Basin near Nowra, the Cooks River near Sydney and the Hastings River further north.

“Heavy rainfall is occurring around Nowra and Jervis Bay, and is expected to extend northward later this afternoon and evening,” the bureau said.

“Conditions are expected to ease across the warning area during the latter parts of Friday as the trough moves back south and weakens.”

#Sydney has now exceeded 1,000mm of accumulated rain since the start of the year. In an average year, the city would usually reach this mark around October, so this is about four months ahead of schedule.

Full story here: https://t.co/IBOpZX2M8u pic.twitter.com/Svow9wNTBv

— Ben Domensino (@Ben_Domensino) June 4, 2024

This week’s deluge continues an extremely wet start to 2024 for Sydney and other areas of coastal NSW.

Weatherzone reported earlier this week that Sydney had already “amass[ed] one metre of accumulated rain since the start of the year”.

“The city has received above-average rainfall in four out of the last five months and despite only being a few days into June, it has also already exceeded its June monthly average after a bout of torrential rain on the weekend,” Ben Domensino wrote.

Sydney had recorded 1020 millimetres of rain for the year by Monday. In an average year, that total would not be reached until October, and about 1200 millimetres for the entire 12 months.

“This year’s running total … puts it in the top 2 per cent of historical records up to this point in the year,” Domensino wrote.

“However, it is far from unprecedented. In 2022, it only took three months for Sydney to exceed one metre of rain and by the end of May, the city had received more than 1.5 metres of rainfall.”

Sydney had marked its wettest year on record by October 2022, when more than 2200 millimetres had fallen.

Conditions in the harbour city are expected to ease by the weekend, with showers expected on Saturday ahead of a clear Sunday.

-with AAP