The pattern will be amplifying through out the northern Hemisphere in this period and beyond.  The pattern that I’ve been envisioning for this winter will start to really take hold as high latitude blocking develops and that includes the negative NAO signature.  

However, before we get to that exciting and interesting pattern, we have to get through Thanksgiving!  Besides being loaded down with tons of turkey, mashed potatoes, and pumpkin and apple pies; the main theme on the week will be the cold air and scattered snow showers rotating through the region.  The low pressure system that develops to the north of the forecast area on Tuesday will also develop a strong 500 MB low over New England.  This low will send disturbances rotating through the forecast area through Thursday with partly cloudy skies and a risk for isolated snow showers.  Although temperatures will not be as cold as last week, high temperatures will continue to average 4 to 8 degrees below normal through the period.

The storms that I expect to impact the forecast area in early December will begin to show up at the end of the week and into next weekend.  However, I do not see this current set up as a favorable environment for frozen precipitation along the coast.  The negative NAO blocking needed for high pressure to lock into southwestern Quebec and New England is not present and thus there is no support for CAD.  Instead, a surface high is to the east of New England, which would support a more easterly wind and thus a high potential for rain rather than any frozen precipitation along the coast.  However, take heart, as this low pressure system (Miller A type) will help develop a negative NAO blocking pattern, which is seen on ensemble guidance of the GFS and ECMWF.  The key here is we are going through a transition period, which favors storms along the east coast.

As for the storm on Saturday, as I was explaining, most of the coastal plain will see rain out of this storm track.  The low is off the coast, but there is not mechanism to keep cold air locked into the coast, so temperatures will warm above freezing making for a cold rain next Saturday.  The interior however will have a good chance of accumulating snowfall from this low pressure system, especially over the Poconos, higher elevations of Sussex, New Jersey; the Hudson Valley, and northern Connecticut.  How much is uncertain, as I will have to nail down the track of the low pressure system specifically, which I won’t be able to do yet.