Parts of Victoria could see three months’ worth of rain as storms forecast for Australia’s south-east

Widespread rain and thunderstorms are forecast to drench south-eastern Australia from Thursday, with the heaviest falls expected across Victoria.

A trough moving east across South Australia was expected to combine with a low pressure system moving through the Great Australian Bight on Thursday, according to the Bureau of Meteorology.

The two systems would combine into a slow-moving low over Victoria, eastern South Australia and New South Wales, bringing widespread storms and dumping large amounts of rain.

Most of Victoria could expect rainfall totals of 25-50mm over the coming days, according to Dean Narramore, a senior meteorologist at the bureau. Widespread rain was already developing across western and southern Victoria, he said, which would “ramp up” and spread throughout the state on Friday.

Parts of Gippsland, as well as the central, eastern and Otway ranges regions, could experience rainfalls exceeding 100mm – and some areas could record up to 150mm.

“That’s equivalent to one to two months of rainfall, maybe even three months’ worth of rain, in any areas that get 150mm,” Narramore said.

Melbourne would also be “quite wet”, with 30 to 50mm of rain expected to fall over the coming days, Narramore said. Flood watches were in place for parts of Gippsland, north-east and central Victoria.

Thunderstorms were also expected, along with the potential for damaging winds in coastal areas of Victoria on Friday and Saturday, according to the BoM.

It was an appropriate start to October, coinciding with the beginning of Australia’s peak thunderstorm season, which continues into January.

Canberra and Sydney could also expect rain and storms on Saturday, as the weather system moved across New South Wales.

“Showers and storms are likely to impact the entire Sydney basin, with the potential for accumulated rainfall totals in the vicinity of 50mm in some suburbs due to a combination of persistent showers and localised downpours during thunderstorms,” according to Anthony Sharwood at Weatherzone.

However, the wet and potentially stormy weather was expected to clear in time for the kickoff of Sunday’s NRL grand final, he said.

“The morning and early afternoon could see a lingering shower in parts of Sydney, but as the day goes on, a drying trend will set in, creating near-perfect conditions for a fast flowing game of NRL footy.”