Australia on the long term 30th August

Hello all it’s the Snowy Hibbo! Welcome to the new website, still a work in progress at this point. Let’s have a final look at the long term forecast for Australia this season.

5-8 September

This system looks like two minor hits of snowfall per EC. Expect 5-20cm all up from this system, with more snowfall expected in the more southern snowfields.

13-15 September

Here is a scenario progged by EPS Control and GFS in slightly different manner, but refuted by larger ensemble support. It could be a potential light-moderate snowfall system, but it looks a bit early for longwave support.

16-20 September

This particular period is supported by a longwave going through the region based upon both EC and GFS longwave projections. You would expect a moderate sized chance at a good snowfall here, given the decent node. It depends a lot on the status of the AAO, and whether it will negative for this period.

27th September – 1st October

This has been signalled by both EC and GFS as the next period for a coldfront to occur. We expect a -AAO to be in place by this point, which is good for more snowfall. This is probably the last real chance to get some decent snowfall.

Climate Drivers

MJO

Both GEFS and EPS show a weak MJO on RMM charts (below)

A few models do show some signals in the Phase 4-5-6 region over the next 10 days, which would be positive for our snow. Also VP200 plots do show a MJO signal in our region as well. But I would expect little impact over the next fortnight, if there is any impact, it will be slightly positive for us.

Stratosphere/AAO

This is a long-winded discussion ahead, for this. Below is a tweet acknowledging the historic SH Sudden Stratospheric Warming that is now upon us.

The key things to know is that a SSW warms and weakens the polar vortex in the stratosphere. And that descends into the troposphere closer to the surface, and pushes cold and node activity towards the mid-latitudes and us in SE Australia. We now have a SSW, but the impacts will slowly trickle down to us.

The -AAO in the chart above is what we want for more coldfronts and potentially snowfall. I expect it to descend down by the 20th of September. This is why the 15th-20th Sept period is a bit in the middle, because it is a transition period. But we should expect conducive conditions to more cold and potentially snowfall from the 20th of Sept to about the 2nd week of October. Impacts may run deeper into October, but I doubt that a major snowfall more than 10cm or so, could occur that much deeper into Spring in this particular timeline.

AAM

The GLAAM is currently negative globally, which is positive for our snowfall. Regional GLAAM is currently pretty neutral.

Previous episodes of associated positive South American Mountain Torque, that overall has remained above average, is one of the major reasons for the current SSW.

Overall, I expect the top-up and sunshine in between theme to continue until approx the 15th of Sept with a potential coldfront risk then, and -AAO creating more options for coldfront risks later in the month and into October.

Disclaimer: There is lower skill associated with using long range model forecasts to find snow systems.

A quick look back to my seasonal forecast early this year will find a prediction of 176cm for Spencer’s Creek. We are currently at 228.8cm, so yet again an above average season, thanks to unexpected stratospheric and -AAO events. Always working hard to improve the forecast 🙂


Thanks for reading this Australian long range snow forecast, follow me on Twitter @longrangesnow and subscribe to my email list by clicking on the tab on the main header above. This is the last one, so I will see you next year for those of you who only ski here in Aus. For NH snow hunters, the first outlook should be out Sunday. See you then hopefully.

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