Apologies for a lack of posts in the past weeks, life has got a little busy at the moment unfortunately. Onto the analysis….
The LWT is expected over SE Australia early in August, which means we might see a system off the backend of the larger node. There is plenty of signs that it may peak over SW WA, as has been happening with a number of systems due to stronger westerly (more convection) activity in the Indian Ocean in the past week or so. The tropical signal is forecast to move towards Australia in the first week of August, but it may not come soon enough for us to enjoy the benefits of a SE Australian peaking system.
It also increases the likelihood of a trough across the continent stretching from the SE to the NW of Australia, bringing down tropical moisture.
You can see this clearly on GEFS, but we also have a decent southern trough based off of this, that can bring decent cold and possibly snowfall.
EPS (EC ensembles) show a stronger trough from the south, but it isn’t a very deep cold front, so obviously not going to lead to maximum reward in terms of snowfall. But there is nonetheless some potential for something.
A vague cold front linked to the NW trough is to be found on GEPS, leaving all of the ensembles relatively on the same page, albeit with varying strengths. They have consolidated upon the weakfish cold front feature in the last couple of runs, prior just featuring a vague trough. It is possible it may return to this given a poor +AAO status, but there is certainly still a chance.
Overall not the most exciting setup there is, but there is certainly potential for something there, if all it is would be a clipper with 5-10cms, we will take anything at this point.
If we take the LWT chart at face value, we may see some potential around the LWT peak on the 10th and 11th and in the days succeeding it. But if GFS is anything to go by, it looks to be a Southwest WA peaker as well.
EC Monthly doesn’t like it very much.
If we continue to follow the cards indicated by the GFS LWT, we are lead to this date range.
EC Monthly indicates some activity in the Australian region during this period, and further into the last week of August, that may bring some potential for troughing in the SE of Australia.
It looks strongly likely unfortunately that we are heading into a positive phase of the AAO, which is bad for Australian snowfall. As one can see from these charts, it is rather cyclical in nature which gives us some ability to predict it’s manifestations. Based upon this notion, August is likely to be largely a +AAO month, with a more negative outlook in the last third of the month being potential.
It is also important to note that the stratospheric polar vortex at it’s upper extreme here remains strong and cold, so it is unlikely to help us with any real change to the SH atmospheric circulation to help snowfall.
EC is a fan of a strong +AAO event, weakening out chances in that first week of August.
GEFS is forecasted a potential push to a -AAO reprieve from the 10th of August into the mid-month period.
On the more positive side of things, the MJO is very possibly moving into our region, at least in some capacity.
You can see the GEFS MJO forecasted tropical wave, move into the Australian region, which is beneficial to us.
Other modelling like that from ECMWF EPS is less hopeful of such a direct incursion into the Australian region, preferring to stay with the pre-existing base state that is leaving us in limbo, benefitting SW WA more than us.
This shift in momentum is leading towards a more positive AAM, as per CFS.
Although the correlation with the AAM on the data is better with a more negative outlook for snowfall, it could also possibly symbolise a little bit of a shake up in the pre-existing base state, which might get us out of this mundane pattern over the past few weeks (particularly in Victoria).
So there is still hope, but yes the numbers are not in our favour with the AAO at the moment, with some potential in the tropics. We shall wait and see.
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