Storms and gales will hit large parts of Australia’s east coast this week as parts of the country experience a wild start to winter, with the possibility of snowfall in southern Queensland.

Temperatures could drop as low as -2C on Tuesday on the granite belt near Stanthorpe, close to the Queensland border with New South Wales, according to the meteorologist Michael Gray.

He said there was a 20% chance that snow would fall in that region in the form of a “flurry”, which means that the snowflakes don’t accumulate on the ground.

The Bureau of Meteorology has issued severe weather warnings for 100km of the NSW coast and for large parts of Victoria, with extreme weather predicted for the rest of the week.

Sydney, Newcastle, Wollongong, Gosford, Taree and Port Macquarie are forecast to experience damaging winds and dangerous surf this week, with the bureau predicting 70km/h to 90km/h winds along coastal areas.

The severe weather warning stretches from the Victorian border in the south up to Kempsey on the NSW mid-north coast. Melbourne, Geelong and large parts of Victoria will experience heavy rain due to a low pressure system moving over the Bass Strait.

On Monday morning Melbourne’s city centre and western suburbs experienced heavy showers, with the possibility of more in the afternoon.

A nice band of rain across the outer western suburbs at the moment! #Melbourne CBD saw some heavy rain before sunrise, looking clearer at the moment but should see rain and showers redevelop this morning https://t.co/g7qJ6g2esx pic.twitter.com/3mBjyplybI — Bureau of Meteorology, Victoria (@BOM_Vic) June 2, 2019

But that could ease throughout the week, with the bureau forecasting sporadic showers in the city on Tuesday, Wednesday and Thursday.

Flash flooding could occur in the Gippsland region and central regions of the state, with 80mm of rain falling in 24 hours across high country, and 35mm across the rest of the region, the bureau said.

Blizzard conditions may also develop in alpine areas on Monday night, where winds are predicted to reach 120km/h.

In Sydney the bureau is forecasting a 100% chance of rain on Tuesday and a 90% chance for Wednesday. Up to 50mm of rain could fall on Tuesday, mostly in the morning.

Across the two states, strong winds have the potential to wreak havoc, and the NSW State Emergency Service has advised residents to move vehicles under cover or away from trees, to secure loose items and to stay clear of fallen power lines.

The wet weather comes as councils across NSW introduce water restrictions amid falling dam levels.

In western NSW, Tamworth’s Chaffey Dam is at 24% capacity and the city is under level-four water restrictions. That will be upgraded to level five if the dam drops below 20%.

Sydney introduced level-one water restrictions last week – which bans the use of standard sprinklers and unattended hoses, and only allows the watering of lawns before 10am and after 4pm, as long as the hose is fitted with a trigger nozzle.

Last week Dubbo introduced level-two water restrictions, which involves an “odds and evens” system. Houses with even numbers are allowed to water their lawns on calendar days that are even numbers, and vice versa for their odd-numbered neighbours.

• Australian Associated Press contributed to this report