Sydney is on track to set a new record for its wettest ever year, with more than two months still to go, as the city braces for another 100mm of rain over the next few days.
The soggy city has recorded 2,129mm of rain between 1 January and 4 October – just 65mm shy of the record set in 1950, when the annual total reached 2,194mm.
Parts of inland New South Wales, central Queensland and along the Murray River in Victoria are bracing for flooding as a heavy rain band settles in for three days of steady falls, causing rivers to rise in already sodden catchments.
The 2022 rain total for Sydney’s Observatory Hill weather station has already overtaken the second wettest year on record in 1860, which recorded 2,110mm. In the city’s west, Parramatta has had 1,664mm of rainfall in 2022, which currently makes it the fourth-wettest year on record, with only another 50mm required to overtake the third and second-wettest years.
Flood watch alerts have been issued for almost 40 waterways in NSW.
“Of particular concern are our rivers around northern parts of NSW including the Namoi, Peel, Macquarie, Bogan River where we could see major flooding in the coming days with rainfall,” meteorologist Dean Narramore said. “Some of these rivers are already experiencing major flooding.”
The Belubula and Lachlan rivers and Macquarie River at Bathurst may experience moderate to major flooding, he said, with minor to moderate flooding through the Hunter and Hawkesbury-Nepean rivers.
“Many of our gauges across inland NSW are experiencing minor, moderate or major flooding,” Narramore said.
Some have shown river levels increasing even before the rain began to fall. “That’s why we’re so worried about the rainfall in the coming days,” he said.
A severe weather warning for heavy rainfall was issued for western parts of NSW from Wanaaring, near Bourke, to Hay and Deniliquin in the south. That could bring flash flooding as the rain system moves east, the Bureau of Meteorology said.
“A trough over central Australia is pulling large amounts of tropical moisture ahead of it over western NSW, bringing a rain band and areas of thunderstorms,” the bureau said. “Heavy rainfall which may lead to flash flooding has developed.”
Twenty-four hour falls of up to 70mm were likely, while localised falls of up to 100mm were possible, the BoM said. Burndoo, south-east of Wilcannia, had already been lashed with 61mm in the six hours to early Wednesday morning.
The trough was expected to bring widespread rain across western and southern inland parts of NSW on Wednesday and Thursday, before a second trough moved west into the weekend.
The BoM said the second downpour would threaten already wet coastal catchments including the Paterson, Williams, Hunter, Hawkesbury and Colo Rivers and Wollombi Brook, where dams were almost at capacity.
Sean Kearns, the assistant commissioner of the New South Wales SES, told the ABC he was “really concerned” about the impact on communities in western and south-western parts of the state already battered by two months of floods.
“What we’re going to see is significant amounts of rain, sometimes the monthly rainfall in just a couple of days, if not more,” he said.
“This is falling already over already saturated catchments. We’re particularly concerned around the areas of Gunnedah, Wee Waa, Warren, Bathurst, Forbes, Gundagai and Tumut and also Wagga Wagga.”
The NSW emergency services minister, Steph Cooke, said any extra rainfall would increase the risk of riverine and flash flooding.
“Our catchments are completely saturated,” she said. “Our soils, our landscapes are saturated. Our dams are full. Our rivers and channel systems are full to the brim.”
The NSW premier, Dominic Perrottet, said it would be a “difficult week” and “difficult summer” ahead, urging communities to follow SES advice.
Queensland and Victoria were also on flood alert with river rises and minor to moderate flooding likely in hard-hit regions.
Kerang, Echuca, Shepparton and Rochester were under a severe weather warning, as the trough and low pressure system over South Australia pulled tropical moisture over Victoria’s north.
All river catchments across northern Victoria were under flood watch, with the bulk of the rain expected on Thursday and Friday.
The trough was pulling tropical moisture into south-west Queensland, causing a rain band, patches of thunderstorms and possible flash flooding on Wednesday into the early evening.
Cunnamulla, Quilpie, Hungerford, Adavale, Barringun and Wyandra were expected to receive the brunt of wild weather, with isolated falls of up to 100mm possible.
Adavale road had already received 88mm of rain in the 24 hours to Wednesday morning, while the Upper Quilberry and Loddon catchments had received around 80mm.
Emergency services in South Australia have already begun cleaning up after the cold front, which saw wild storms that severed power lines, brought down trees and shut off roads on Tuesday evening. More than 5,000 homes and businesses were without power.