Farewell Fall; Welcome Winter

December, January, and February are the 3 coldest months of the year climatologically here in the Mid-Atlantic region and more specifically, Dec 5-Mar 5!  So as we say goodbye to the extremely wet fall thanks to Irene and Lee in August & September, the eerily strange snowfall of Halloween weekend, and the amiable mild November, we now await what December has in store for us, many wondering where true winter wx is?  Well, be careful what you wish for!  Next week I do believe that much below normal temps will embrace the majority of the nation and the potential for an early season snowfall is most certainly on the potential radar.  Both the GFS and the Euro show some rather strong digging troughs entering the lower 48 that will at the very least offer intense lake effect squalls and could generate a larger scale synoptic storm over the northern Mid-Atlantic and New England states for the middle of next week.  Before we get to that, lets look at the climo graph for KMDT through November.  Note the recent warmth the last week of November.  Also note the 70.40" of rainfall to date!  Amazing!

Now onto next week with numerous maps.  I will first show the GFS for next Wednesday 3 hours apart.  What this map shows is a very strong trough that is spinning up a storm that will potentially dump ~0.75 inch of precip falling as snow according to the 0ºC line being to our south and east.

The above map is for Wednesday morning and the map below is for late morning Wednesday:

And the upper air maps to support this cyclogenesis:

The above is the 500 mb vorticity map and the below is the same parameter for again late morning Wednesday.  That is a strengthening negatively titled trough which has the potential to deliver a fierce bout of winter wx!

And later in the day Wednesday...that is one angry looking vort max!  Things may be rather volatile for the middle of next week.

The ECMWF agrees to some extent, but not with the exact timing.  Look at the depth of that cold pool!

With another severe shot of cold waiting in the wings for a second shot of Arctic air arriving later in the week and next weekend.  That is a huge Arctic High at 1040 mb lurking over the Canadian prairies.

Time will tell how all of this transpires.  But the models are telling us that the pattern is changing and cold air is on the move.  Does this lock in and hold the cold for the 1st part of the winter or are these troughs transient?  It's still a bit murky.  Here are the GFS ensembles take on the NAO trending negative by the middle of December.  There is great spread however among the various members of the ensembles as you can clearly see.

One graphic that was straight up today was the Dow!  It was the Dow Jones greatest one day increase since March of 2009!  The Fed wants the American taxpayers to back the IMF to help bail out Europe...unbelievable.  The central banks of numerous countries are all considering throwing good money after bad.  At least the markets rose sharply today in response to all of this lunacy!  One just has to wonder where these flim-flam economics are going to land?  Or crash land!?!

Enjoy the end of the week.

Smitty

AA:  Watching some very cold air with some extremely energetic upper level energy aimed at us towards the middle of next week.