I am not going to make a prediction of September ice extent this year. It is a crap shoot, based on 15% ice concentration – which is highly dependent on the winds in August and early September.
More meaningful measures are ice thickness and ice age.
PIPS is dead, so I can’t make any more comparisons of thickness, PIPS is back from the dead and NSIDC provides ice age data.
My forecast is that come the end of September, the amount of multi-year ice will again increase relative to last year, as it has done every year since 2008. In 2013 there should be an increase in the amount of five year old ice, because that is when the 2008 ice will have aged five years.