The prospect of a West Based El Nino is becoming more possible, which would enhance good snowfall chances in the east US this winter. Take a look at the latest CFS v2 forecasts for Nino regions 1+2.
As shown above, the warmest anomalies have been centered in the eastern portion of the ENSO monitoring area. However, as seen in the forecast, there is more of a potential for the temperatures to lower, which either means the Nino is dying off or is transferring to the west. I believe the latter is more likely after seeing the Nino 3.4 region forecast below off the CFS v2.
As the Nino 1+2 regions cool off, the Nino 3.4 region would seem to warm up as we head into winter. What these two charts indicate is a movement of the El Nino-status warm waters westward (apologies for the alliteration) into the western portions of the ENSO monitoring area as we head into fall and eventually winter. Time will tell, but this is what could be panning out going into the late months of 2012.