An exceptionally cold air mass from Antarctica will cause low-level snow in southeastern Australia during the next 48 hours.

The cut-off pool of cold air will spread over Tasmania, Victoria, and southern NSW between now and Wednesday. As temperatures plummet, snow could reach places that haven't seen flakes for several years.

Image: 500hPa temperature and height over southeastern Australia on Tuesday morning according to the ECMWF-HRES model, showing cold air from Antarctica over Tasmania and southern Victoria.

Forecast models suggest that it could get cold enough for snow to reach around 200-300 metres elevation in much of Tasmania on Tuesday. Some places in the state's west and south could even see snow falling close to sea level when the coldest air moves through. Higher terrain in western and southern Tasmania are likely to see snow falling each day between now and Friday, causing a decent accumulation of more than 20cm in some areas.

While the air won't be quite as cold once it crosses Bass Strait, snow is still going to reach low levels in Victoria and far southern NSW on Tuesday and Wednesday. 

It should be cold enough for snow to reach 400-500m elevation in eastern Victoria and far southern NSW from on Tuesday or Wednesday. Some models suggest that snow could even reach around 200-300m in some areas, although this would only be light falls.

The outbreak of cold weather over the next few days will also be accompanied by blustery winds, rain, and hail. These wintry conditions will be dangerous for some outdoor activities and pose a threat to livestock. They will also make driving dangerous in places where it will be cold enough for ice to form on roads. As a result, bushwalkers alerts, road weather alerts, and sheep graziers warnings have been issued in some areas.