A quick hunt for model predictions on Arctic extent finds
Huang et alFigure 3, to which I've added a circle to show that the models predict that we should currently be somewhere near 4m in September extent:
Last four years NSIDC September monthly:
2015 4.62
2016 4.53
2017 4.82
2018 4.71
Last four years JAXA minimum daily:
2015 4.26
2016 4.02
2017 4.47
2018 4.46
Obs copied from the June poll threads.