May 9th: Rain and snow to end the week
Last week’s rain system was a cut-off low, and brought this much rain to Victoria:
When the low was back to our west, north of the ranges gets the bigger falls (unless it can push over). Then the south has the bigger falls when the low has moved to the east - but by this stage, the low was too far away.
So, the far west missed out, as well as the rain shadow areas of Melbourne - but there was a soaking for parts of southwest VIC, and much of Gippsland.
A cold front pushed through on Tuesday into Wednesday this week, delivering this much rain:
10 to 20 mm for the southwest and western Gippsland, less for much of the rest.
The week ends with another cold front - this one much stronger, and it comes up from the south. It should also develop another cut-off low.
There may be raised dust again in the Mallee, after only a few millimetres of rain on Tuesday. Dust is always a possibility when you have strong winds and dry ground, and the rainband has a defined leading edge to it.
The rain (and thunderstorms) should slowly spread through western Victoria on Thursday, then the east on Friday, but the cut-off low could spread some of the bigger falls into the northeast quarter (rather than just across the south and ranges, as you would expect with a front).
Here is what the models are forecasting, as of Thursday morning:
This suggests the bigger falls will be over the southwest, then central parts (as the cut-off low develops).
Melbourne should see 10 to 30 mm of rain.
This front comes up from the south and has a pool of cold air.
It will feel absolutely freezing on Friday when that is over Victoria.
But the path of the cold pool of air is over western parts of the state, so we may have snow to 1000 metres (snow falling down to 1000 metres above sea level, and rain falling on all the terrain below that) over the western ranges.
While the snowline over the northeast (where our alpine resorts are) is more like 1500 metres.
You can see timelines for all the different alpine resorts here.
This shows the path of the cold pool… snow to 1000 metres in the west, but only 1500 metres at the northeast ranges (the change from blue to yellow):
This cold air means the rain may have wintry hail in there too. You can read more about this phenomenon here.
But in summary… a period of rain, that is cold, wet and windy!