Andreas,
Thanks, so it is mixed skies, would be interesting to see the range around those averages, I'll have a look at the paper tomorrow.
Thing is, HP in the arctic doesn't necessarily give clear skies. In fact HP combined with a warm airmass is a very 'dirty' affair, and actually tends to fill the area up with fog. The LP by contrast will fill the arctic with cold snowy air which after the centre has moved on will give way to clear, fogless, cold skies. Upper troughs in the arctic seem to really cool down ridges. If we look at the area around Severnaya Zemlya which is going to be dominated by a ridge for the foreseeable future and look at the 850hpa theta E values (GFS):
31st July: 31C
4th August: 10C
5th August:20C
Before the LP we had fairly mild conditions, the LP then caused a dramatic change in the airmass reducing theta to only 10C, but crucially even after the LP moved on and the cold flow was cut off, the thetas did not rise back to their initial with the initial rapid warming slowing to a snails pace some 10C colder than original. The change in quality of the airmass will also probably clear the fog, this is far from simple.
For those that haven't heard of theta E, its full name is the equipotential temperature and it is the temperature one arrives at when condensing all the available moisture and releasing the latent heat directly into the air. Theta E not only considers, therefore, the temperature but also the humidity. Lower values represent colder, drier air which can only be a good thing.
Given all this, and the input from Chris and seaicesaloir, I'm still unsure whether this LP is friendly though I must say I am leaning in that direction. It is true that LPs tend to suck air from the lower latitudes, but this is a bigger issue when the LP came from the lower latitudes in the first place or when the LP is not centrally based. In this case (yet) neither of those criteria are satisfied so I am struggling to see any major melt coming out of this LP.
Thanks for the information.
I too am rather at a loss as to what August will bring, 2012 is probably out, 2013 and 2014 are probably out. But I wouldn't bet against 2015 getting into second place, that makes the range somewhere between second and fifth place...
Yes high pressure doesn't guarantee cloudless skies, but I have spent enough time frustrated at getting views of the ice to know that it is more likely to get good large swath views under HP.
If I am correct in my interpretation of compactness meaning that after the first week of August the emphasis shifts from radiative melt to melt from the edges of the pack (as also suggested by Blaine based on my volume rate of change / insolation graph), then the AO ensemble is looking interesting.
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtmlThe 11 member ensemble is grouping nicely for a shift to +ve AO, which means the collapse of the HP dominance and a shift to LP dominance. And that at about the cut off time we've been discussing, about the end of the first week of August.
The Beaufort low seems to wander about around Beaufort and into the CAA, as you say it's hard to determine what the effect will be without knowing exactly how it will be set up. Beaufort extent in winter tops out at about 0.53, it is currently 0.36, of the post 2007 years only 2013 was higher. However Beaufort area tops out around 5.1 over winter and is currently 0.14, by this time 2008 and 2012 were virtually zero. Given behaviour over the summer, I think that multi year ice is stopping the decline of Beaufort, this may continue through August. I wouldn't bet on it, but my
suspicion is that Beaufort has more to lose but won't be on the low side of the post 2007 distribution and will not be ice free by mid September.