Winter is kicking down the door across most of the country, and the Bureau of Meteorology (BOM) says the aggressive cold front and low-pressure system will impact every Australian state and territory over the coming week.

The BOM held a snap press conference on Monday morning at its Melbourne headquarters to discuss the “impacts from damaging winds, abnormally high tides, and a drop in temperatures to be felt across multiple regions throughout the week – including in areas of Western Australia, South Australia, Victoria, Tasmania, NSW, the ACT, and Queensland.”

South-eastern South Australia, Victoria, eastern NSW and Tasmania will feel the brunt of the system, including “below-average temperatures, showers, low-level snow and brisk winds”.

Meteorologists have been watching the system develop for some time and say it’s not just chilly conditions that are on the way. “Severe weather warnings will continue to evolve over the coming days, so people should continue to monitor warnings”, according to the BOM.

Across the south, severe thunderstorms are expected, potentially bringing hail, destructive winds and significant rainfall to places where soils are already saturated and water storages near full – posing a risk to property and life from river rises, flash flooding and falling trees.

The impact was felt in Adelaide on Monday when the ABC is reported a “mini tornado”. More than 200 calls for help were placed to the SES as severe weather raged through the Salisbury region; more than 1800 homes across the northern suburbs were also said to be without power.

As expected, the front reached the east coast by late Monday. Rain and damaging winds lashed NSW last night, leaving thousands of homes without power and resulting in nearly 600 calls for emergency assistance. Today might be clear and crisp, but the blustery conditions will ramp up overnight with Wednesday set to bring more bitter weather. Sydney is forecast to hit just 15 degrees on Wednesday, and winds in the harbour – and along the coast – could reach 60 kilometres per hour. The blowy weather is expected to ease by Wednesday afternoon and evening, but temperatures will stay below average. Locations that may be affected include Taree, Newcastle, Sydney, Wollongong, Nowra, Batemans Bay, Armidale, Canberra and Goulburn.

Further south, Melbourne is set to be pummelled by a “vigorous south-westerly airstream” that will strengthen over Tuesday night and into Wednesday morning as a series of embedded cold fronts crosses the Bass Strait. Gusts of over 90 kilometres per hour are possible, including in the metro area. Wednesday morning will see the highest risk for damaging winds, which are expected to ease below warning thresholds by lunchtime.

The front will see temperatures nosedive for at least the next week. Maximum temperatures are forecast to plummet 3 to 6 degrees below the May average as far inland as south-west Queensland and even into the southern Northern Territory. And the BOM says the gusty conditions will make it feel even frostier.

The chilliest air will move through Victoria, Tasmania and south-eastern NSW on Tuesday, with the snow level falling as low as 600 metres amid potential blizzard conditions. Ski resorts could cop up to half a metre of snow, and outside the alpine regions even the Dandenong Ranges could see light falls.

Huge swells are also expected across much of the southern coastline, and some parts may see dramatic tidal behaviour. The BOM advises those in South Australia and Western Victoria especially to stay up to date with warnings and to check conditions.

As the low moves into the Tasman Sea from Wednesday, rains will follow in the cold air left in its wake. There could be a brief but chilly reprieve on Thursday, with a bit of sunshine set to appear. But the calmer conditions will be short-lived: another front is expect in the south-east on Friday, bringing more cold and windy weather over the weekend.

The BOM is recommending people continue to keep an eye on warnings through its website or the BOM weather app – and to always follow advice from emergency services.