The image above is observed 70mb stratospheric values, from January 2011 to present. I circled the summer months of 2011 and 2012. If we look at summer 2011, we see the lower stratosphere was below normal. When the lower stratosphere is below normal, it is typical to see a positive NAO, thus above normal temperatures. Sure enough, in the winter of 2011-2012, the stratosphere was well below normal, and temperatures were well above normal.
This summer, we have seen the stratosphere keeping at roughly normal levels- an encouraging sign for the upcoming winter. If one uses the summer months to help determine the winter forecast, like what I observed above with 2011-2012, I would say that the stratosphere appears inclined for a good winter, as far as the El Nino goes for the East Coast.
I will have more information when the Official 2012-2013 Winter Forecast is issued at 12:00 PM CT on September 8.