It doesn't seem to have been transitory, it has dominated July so far and looks set to continue throughout the rest of July. My expectation is for it to continue into August, that however is just an expectation based on behaviour in 2007 to 2012.
I have previously defined some sectors of interest in watching sea ice, they are shown in the following graphic, based on Cryosphere Today.
The following plot shows anomaly of extent for various sectors of the Arctic region.
Since the start of July the Siberian sector (red) has finally started to fall at above average rates, leading to an above average loss of extent in Northern Hemisphere extent, as shown in the anomaly plot for the Northern Hemisphere.
So the race to the minimum is finally on. But what has caused this?
In late June sea level pressure (SLP) showed a high over Greenland and the Arctic Ocean dominated by low pressure around the landward periphery.
I commented in my June Status post that this was looking similar to the 2007 to 2012 SLP pattern which caused an Arctic Dipole in those years.
Then in July the pattern became far more typical of the 2007 to 2012 summer average.
The interaction between the low across the Eurasian coast and the high from Greenland and over the Arctic Ocean causes the winds associated with the Arctic Dipole. Low pressures circulate anti-clockwise, high pressure circulates clockwise. In the following graphic I have illustrated the effect on the SLP pattern for 2012. The thick black arrow being the Arctic Dipole driven flow of winds.
Returning to July so far, here is the vector wind for 1 to 16 July 2015, note that this is rotated such that the Eurasian coast is on the left hand side.
The dipole flow in July is clear as a strong (reds/yellows) band of winds blowing from the Bering Strait towards the Barents Sea.
If this dipole persists through the summer such that the July August average shows such flow, then 2015 should fairly easily fall towards levels similar to the September minimum of 2007 or 2011.