News

Significant cold outbreak to end the week. Alpine snow from late Thursday afternoon to early Saturday, 15 to 25 cm. Very cold with snow to near sea level Friday night.

Summary:

One last cold front is sliding away and we stay in a belt of northwesterly winds until Thursday, thanks to a band of high pressure up over the interior of the country. It will remain windy, and too warm for snow.

A cold front is building south of Western Australia, and will peak over the southeast of the country on Thursday/Friday, with a significant cold outbreak. Here are a few things about this system:

• The cold front will cross through on Thursday afternoon and evening. An associated low pressure system will then pass just south of Tasmania, pushing a trough or second surge across Victoria/southern NSW on Friday.
• A rainband will affect the alps on Thursday afternoon / evening - rapidly changing to snow in the late afternoon (western alps) / evening (eastern alps). In fact, we should have snow levels as 1800 metres over the east and 600 metres over southwest Victoria, at the same time - this is a very tight temperature gradient, the snowline will rapidly lower.
• The front will have a weak feed of tropical moisture as it passes south of Western Australia (good for producing heavy snow) but the associated low is south of Tasmania (bad for sustained/heavy snow), BUT there is that second surge (good for sustained/heavy snow). There is not too long before it changes to snow (we will see most of the precipitation as snow).
• This brings a significant cold outbreak. Snow will fall down to at least 500 metres, across southern Victoria - and I would expect we will see falls down to 300 metres over the Melbourne / central area, and Gippsland on Friday evening. Tasmania can expect snow to sea level on Friday evening (if there is precipitation).

Alpine areas can expect snow from late Thursday afternoon to early Saturday morning, bringing 15 to 25 cm.

The next high moves across us on Saturday, turning it dry and cold with lighter winds.

Outlook:

The Southern Annular Mode drops back into negative territory - limiting our snow-bearing systems and letting high pressure get in the way. But it should go positive again next week, so there is the potential for a snow system.

High pressure will push cold fronts to our south, but energy from one of these may get moved up over central Australia early next week. These can suck moisture in from the Pacific (wrapping around the high), and produce widespread rain over the eastern states - so this will be one to watch (not saying it is good or bad, just worth seeing how it develops).

Commentary above courtesy of Jane's Weather.  www.janesweather.com