Sea ice prediction updates

I'm a little behind on our updated estimates for the September average sea ice extent for the ARCUS outlooks.

The original outlooks (end of May) were:

3.9 million km^2 -- Grumbine, Wu, Wang statistical

4.1 million km^2 -- Wu, Grumbine, Wang model-based

4.4 million km^2 -- Wang, Grumbine, Wu model-based statistical

The end-June Wu et al. estimate was 4.7 million km^2.

The end-July Wu et al. estimate is 4.57 million km^2.

In other words, it looks like the model has picked up on the relatively (compared to last year) slow decline in ice cover and is keeping more ice around.

What will actually happen, well, keep an eye on reality.  But, in the likely event (it seems to me now) that the purely statistical model is very wrong, time for a new statistical prediction method.  I'm starting to get ideas on how to go about the update.