You have to respect the -NAO, +PNA and – AO when you look at the potential snowstorm coming next week. This is what I have been talking about that the blocking pattern coupled with the La Nina and PNA would bring an extreme event around the 15th of the month and sure enough all the operational models are going in that direction. ECMWF and Canadian models seem to the most potent with storm amounts while the GFS is playing the conservative route but still Cat 3 amounts through the major cities. The upside of this storm is a Cat 4 snow events with some areas having 12-18 inches of snow. ECMWF shows Philly with over 21 inches of snow which would be the seasonal total in one storm. Snow ratios and storm track will all place a critical role in the snow amounts. Think 8:1 ratios most likely. It is interesting to see that the track is not really through the benchmark heavy snows in the cities but with such an convective storm coming into a airmass that is getting colder that’s why the huge snow amounts. Expect rates if the storm comes out as shown of 1-3 inches per hour.