Tuesday: Rain developing later today, heavy overnight, then possibly stormy tomorrow. Next rain system only for the east.
A complex low with a feed of tropical moisture will push a trough across the alps later today/Wednesday.
Rain develops this afternoon, and should be heavy overnight into Wednesday morning. It breaks up to showers and thunderstorms for the afternoon in a muggy, unstable airmass. This should bring 25 to 50 mm of rain. But, there could be a hint of cooler air to let some wet snow occur around 1900 metres from Wednesday afternoon.
We take a break on Thursday, with generally dry conditions, but there are isolated showers, again possibly as snow around 1900 metres.
Another low taps into that tropical moisture and comes down from the north to end the week. The path of the low will determine if there is a lot of precipitation or not much at all, depending on whether a high over New Zealand is strong enough to steer it closer to us.
Latest guidance shows little for Baw Baw/Buller areas, some for Hotham/Falls region and the risk of heavy precipitation in NSW - as rain redevelops on Friday, and persists through Saturday. A weak upper trough should inject some cooler air from Saturday morning with snow to around 1800 metres for the last bit of this.
Sunday is mostly dry, then the next high takes over with a new stretch of dry weather.
It all comes down to a simple equation. To make it snow you must have: low pressure, moisture and cold enough temperatures.
We can guess the moisture part of the equation for the season ahead by looking far away from the alpine areas, and considering the balance of warm and cool water in both the Pacific and Indian Ocean.
Pacific Ocean: El Nino is over and we will have a Neutral or La Nina phase instead. Neutral would be a good source of moisture, and La Nina would be a great source. La Nina would also work to push it towards the alps.
Indian Ocean: a negative Indian Ocean Dipole (IOD) is the most likely situation for this winter. This means that the waters off Indonesia are warmer than the waters off Kenya, meaning more moisture for us to play with. And the atmosphere responds to this imbalance, by pushing it towards the alps.
So, that, combined with warm waters off much of the coastline of Australia, all works to ensure the moisture part of the equation is as good as it can ever be.
But, what about the low pressure and temperature parts?
These are the big questions for 2016. We don’t have any good guidance to show how many low pressure systems will move through, and whether they will take a helpful path. And, all this warm water around us means that our air temperatures may be warmer rather than cooler.
My feeling is that we will have several ridiculously huge dumps of snow (thanks to high moisture), producing some absolutely epic days this season. But what happens in between those only time will tell…