Australia is in for a drenching in coming days, with rain forecast to sweep across the nation.

Forecaster Weatherzone said this week’s wet and stormy weather would mainly target Western Australia until about Wednesday.

It will spread across central and southern Australia on Thursday, and then into eastern Australia from Friday into the weekend.

A second rain-bearing system could also bring follow-up rain to parts of WA at the weekend.

“The two systems combined should soak about 70 to 80 per cent of Australia, and some parts of the country could see rain every day this week,” Weatherzone wrote.

The wet week is due to an upper-level low-pressure system interacting with a feed of tropical moisture – and could also bring thunderstorms, hail and snow in a cold snap days before the official start to winter.

“It’s too early to know which areas of Australia will see the heaviest rain this week, particularly beyond Friday,” Weatherzone said.

“What can be said though is that part of every state and territory will get some wet weather in the next seven days and there is potential for flooding in some areas.”

The change comes after months of stubborn high-pressure systems over southern Australia have led to a prolonged dry spell.

“With that blocking high-pressure pattern finally breaking down this week, we are going to see the first north-west cloudband of the season and some decent rain in every state and territory,” Weatherzone said.

In Perth, which has had one of its driest periods on record through summer and autumn, up to 45 millimetres of rain was forecast for Tuesday and Wednesday.

The Bureau of Meteorology is also predicting up to a further 60 millimetres at the weekend.

That compares to only 24 millimetres in total throughout autumn to Monday morning in Perth – well below the city’s average of 179 millimetres, and short of its current record autumn low of 42 millimetres in 1983.

Up to 30 millimetres of rain is also forecast for Adelaide by Sunday – after the South Australian capital had been staring down the barrel of its driest May on record.

So far, Adelaide has had just 0.6 millimetres of rain in May, following extremely dry months in March and April and no rain at all in February.

In the eastern states, Sydney is likely to be dry until Friday. Then up to 60 millimetres of rain is forecast by next Monday.

Melbourne can also expect up to 20 millimetres from Friday, while Brisbane is likely to get a similar amount at the weekend. Hobart is forecast to remain dry, although it will be cooler with maximum temperatures in the low to mid-teens.

Northwest cloudbands are one of Australia’s most productive sources of #rain in the cooler months but we hardly saw any last winter. In good news for parched parts of Australia, a #northwestcloudband should cross the country this week.https://t.co/1eMrnDR0tF

— Weatherzone (@weatherzone) May 27, 2024

La Nina watch

The wet and windy end to autumn comes as the weather bureau officially moves to a La Niña Watch.

Earlier in May, the BOM said there were signs a La Niña may form in the Pacific Ocean later in 2024.

La Nina is a climate pattern involving cool ocean conditions off Australia’s east coast. It historically brings wetter-than-usual conditions for Australia’s north and east.

BOM climate manager Dr Karl Braganza said rainfall and temperature forecasts were separate to the El Niño-Southern Oscillation Outlook.

“The best guidance for future rainfall or temperature forecasts is the bureau’s long-range forecast,” he said.

“The long-range forecast for June to August is showing an increased chance of above-average rainfall for parts of eastern Australia, and parts of Western Australia and South Australia.

“There are roughly equal chances of above or below median rainfall for most of eastern Australia, including much of Queensland, NSW, Victoria and Tasmania.”

The bureau predicts above-median winter maximum and minimum temperatures for all states and territories.

Its long-range forecast winter outlook will be released later this week.