The map below shows my scenario for the development of a nor'easter while Sandy is being whipped around the trough and getting absorbed into the developing storm. I do not buy the Euro model at all with Sandy coming full bore into the Northeast as a strong hurricane. Things like that just do not happen. What will happen, with the strongly negative NAO, in the development of a storm will most likely occur off the mid-Atlantic coast. The pattern dictates that. Even if Sandy was not in the picture, given the negative NAO, a storm would be developing there.
So what does that mean? When the storm develops, moisture from Sandy should be absorbed into the storm which will move into New England. Heavy rain and flooding will mostly like occur with gale-force winds along the coast. The storm should back west-northwest, and that could mean rain changing to wet snow in the Appalachians of Pennsylvania, West Virginia into western New York. While not the epic storm as shown by the Euro, it still will be a major storm for the Northeast.
I do think you will see the GFS come around to a storm developing off Long Island or New Jersey with time. The Euro should also change direction with time as well. Other models have started in that direction and should all come around to the solution with time as well.
Pattern this weekend will feature a storm in the Northern Plains and up and down heat in the East.
The moonson will bring some nasty weather to the Southwestern part of the country.
Watching the system in the Gulf of Mexico for development. Probably a small chance.
Heat builds into the East while the rain continues for the Pacific Northwest.
Erika will have many issues this weekend includng tracking over the islands with big mountains.