East coast weather: big wet headed for Sydney after month of rain dumped on parts of Victoria in 24 hours

Heavy rain and thunderstorms are expected to hit eastern NSW and south-east Queensland from Thursday, after a resurgence of the weather system that drenched Victoria with a month’s worth of rain in just 24 hours.

Severe weather warnings for Victoria and NSW were lifted on Tuesday as the system weakened and moved up Australia’s east coast.

However, thunderstorms are expected to redevelop over south-east Queensland and north-east NSW on Thursday before pummelling coastal NSW and eastern Victoria on Friday and Saturday.

Sydney could be drenched with up to 70mm on Friday, while some areas of eastern NSW could see rainfall of up to 150mm.

WaterNSW will also be watching if its biggest dam, Warragamba, fills up and starts to spill. The dam, which supplies about 80% of Sydney’s water, was 96% full as of Tuesday and last spilled in late 2022.

Flooding will likely be limited to isolated incidents, due to low levels of rainfall over the past two months, according to the BoM senior meteorologist Dean Narramore.

“Even though there’s been some heavy rainfall, the ground’s very dry, so apart from some isolated flash flooding, there’s been no real major flooding concerns,” Narramore said.

The reinvigorated system is not expected to hit Melbourne, which should face easing showers by Wednesday evening.

The city faced its wettest day since March 2020 on Monday, recording 53mm of rain, after facing its driest March on record last month with a total of only 2.8mm.

Trentham East in central Victoria recorded 97mm since 9am on Monday – the highest total in Victoria.

Victoria’s emergency services fielded more than 500 requests for help as thunderstorms, damaging winds and heavy rain pummelled Melbourne’s western suburbs and the centre and east of the state on Monday.

There were close to 250 reports of building damage and 110 flood-related incidents in the 24 hours to 7am, the State Emergency Service said.

More than 60 call-outs related to trees down on roads during the wild storms.

There have been four flood rescues since midday on Monday, according to an SES duty officer, Erin Mason.

“Mainly it’s been people driving through flood water,” Mason said. “So just a reminder to people to never drive through flood water. If the road is flooded I encourage people to stop, turn around and find an alternate path.”

Mason expected the number of callouts to rise in coming hours as the weather system headed east and more residents woke up to find damage at their homes.

A woman at Daylesford in central Victoria had a narrow escape after falling into a stormwater drain just before 9pm. She fell down an embankment and was carried by fast-flowing water until she grabbed hold of a metal pole, according to Victoria police.

The 58-year-old tried to call for help but couldn’t be heard over the sound of rushing water. She was eventually able to climb to safety, suffering minor cuts and bruises.

The western suburbs of Melbourne including Melton, and parts of Geelong, were among the areas hardest hit overnight.

On Monday lightning caused a 40-minute halt to the Geelong and Hawthorn AFL match at the MCG while the Stawell Gift’s finals were delayed by about two hours due to torrential rain and water over the track.

The weather system weakened as it swept north through NSW on Tuesday, delivering patchy rainfall including a 2.8mm drizzle in Sydney and a 30mm shower in Dubbo.

Storms are expected to redevelop from Wednesday evening as the trough contracts into Queensland and interacts with another upper trough to draw in moisture, potentially producing a low pressure system, Narramore said.

If Wednesday’s reinvigorated low pressure system stays in the Queensland region for an extended period of time, it could form an east coast low system, which would deliver damaging rainfall, strong winds and sea swells.

The BoM said a coastal low is possible but not certain, and the system may instead form a transient low and drift into the Tasman Sea over the weekend.

A separate tropical low is expected to form north of Western Australia later this week, and may develop into a tropical cyclone from Sunday.

“Early next week, there’s a low to moderate chance that it may become a cyclone well off the Kimberley coast,” Narramore said.

Cyclone activity in Australia’s north gave the country its third wettest March on record last month.