Australia on the long term 14th June

G’day it’s the Snowy Hibbo back for another season filled with long term forecasting. This year I am going to do things a little more differently and look at a variety of sources to try and get some dates for snow events, rather than just reflect the EC Monthly Run. I’m still going to use it, but the reality is that there is more to long term forecasting than the one model.

Modelling

As it is currently, we may see a system in the 26-29 June. GFS(below) and EPS Control both think however that there is a big chance that the system will slide below Southeast Australia. There is a chance this may prevail, but most models have indicated a WA Peak, which would mean either that it rains here (again), or it slides south of us, unless there is a strong coldfront behind it to back it up further north. For now I would watch this period, given it is around a progged LWT pass, but the models are not greatly attracted to it for us in SE Australia.

The next thing to look at is the 30th June – 3rd July.
Courtesy of Josh Herman of Consonant Chaos
This period is well supported by the RRWT modelling, and the general rotation of the LWT. FWIW, the LWT is due over SE Australia at the earliest on the 25-26 June, but I am thinking that the 27-30th is more likely (particularly the 27th and 28th) with the new FV3 model speeding things up a bit too quickly than normal. Systems tend to best during a longwave and just after one. So you are looking at the 26th to the 2nd of July as your key dates. As I have said, the models are placing doubts on the earlier period (probably a manifestation of the LWT over in WA). So I am thinking this period is the best bet at the moment.

It is also supported by a general push of a coldfront on GFS, and to a lesser extent on the EPS Control, for what it’s worth. GEFS ensemble shows a slight sign of supporting a coldfront, GEPS ensemble rebukes the idea. EPS is not running out to it yet. EC Monthly supports a decent system on the 1-3 June.

It is something to keep a close eye on, my personal best bet for the next major system for the SE Australian snow region.

Beyond the first days of the next month, EC Monthly is showing a dry outlook in terms of snowfall chances. CFS shows a dry outlook until a clipper type system on the 11th that doesn’t deliver a whle lot either.

CFS next shows a proper system around the 20-22 July. I wouldn’t mention that normally, but something else is coming to town. Our old friend in the Recurring Rossby Wave Train, with a big bullseye.

Courtesy of Josh Herman of Consonant Chaos.

The modelling of the LWT is indicating the 17th to 23rd of July period, as our next big chance for some snowfall.

The not so great news about that, is it looks fairly dry over the July School Holidays on the whole after the first days of July. I will hopefully update the situation on this by the start of them.

Climate Drivers


The MJO is entering our region, which is good news for the next two weeks or so.

We look to see moisture and height support from the MJO over the next little while until the end of the month, even if it delivered us rain this week. If you get a proper system and moisture combination, you are golden.

The GWO is currently circling in the upper phases of the oscillation, we want to see the lower phases.
The MJO is not helping us in this aspect, helping to speed up the extra-tropical zonal winds over the next few weeks.

Courtesy of Victor Gensini atlas.niu.edu
Finally the AAO itself is currently positive. But we are forecast to receive a neutralisation of the AAO on the GFS forecast. Doesn’t quite look like a negative phase, but at least it is heading in the right direction, and this helps encourage the LWT to expand towards us later this month. The signs for polar based cold-front development for SE Australia are more hopeful than they have been this week.
So the lack of the MJO may weaken our moisture source in July, after it brings us with moisture for the rest of this month, with a potential +IOD in our midst too. And the GWO will flatten the jetstream a bit more. But the AAO looks better than it was. And we have no way of exactly forecasting latitude specific GWO anomalies, so it may pan our way, it is just less likely to do so. It’s not amazing or indicative of a great month of snowfall, but we should see ample snow, maybe not as much as we would like however. I’ll be back in a few weeks.

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

Thanks again for reading this European 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.

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