News

Jul 2014
29

Windy and sometimes wet - but there is a significant cold outbreak due on Friday. 15 to 25 cm for alpine areas, and very low level snow.

Summary:

We are in a belt of northwesterly winds, with a band of high pressure up over the interior of the country, and cold fronts sliding away. This makes it too warm for snow, and brings windy and sometimes wet conditions.

There will be a big system though, that changes this pattern. A cold front will build south of Western Australia on Wednesday, and 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.
  • We will see precipitation redevelop on Thursday afternoon - rapidly changing to snow in the late afternoon.
  • 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).
  • The next high quickly comes in, so it is all over by Saturday morning.
  • 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 area and Gippsland at one point on Friday. Tasmania can expect snow to sea level on Friday (if there is precipitation).

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

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 around the middle of next week.