" DEFLECTORS just snapped on Kep' tin..." as 12z GFS jumps in bed with 0z ECMWF

Well the move is now done and over with... but it's not been a loss of just the last three days. The actual time spent in searching for new place and all the other things that one must do when making a major relocation like this... is a lot mo than three days . I ended up losing a lot of free time for the month November. This is free time which I planned to use to for some special projects including a complete revamping of the snowstorm checklist. Now that things to settle down little bit I will have to bust some serious fanny to get the checklist up ands running with a snow event possibly looming on the East Coast with the first significant to storm December 7 -- 8.

The first image I'm presenting is an approximate representation of the 204 hour 0z ECMWF. I made this this map from my copy of the 204 hr with my Microsoft image composer. As you can see them all clearly shows very strong shortwave move into the Tennessee Valley and significant call their damning. Note that the 1044 arctic HIGH we see in the western portions of the Upper Plains at day 6-7 ... has extended a "neck" into the Great Lakes & New England as this system approaches the East Coast. The signature is very clear for CAD.
http://www.wxrisk.com/MODELFOLDERS/today/bgh1.jpg


These next two maps are from the 12z Thursday GFS. This image shows the 500 MB shortwave move into the Tennessee Valley and then across the middle Atlantic states at 180... 192... and 204 hrs. Note that the shortwave is positively tilted but does turn to Neutral tilt at the coast and that the Vort Max travels in a due West East direction across the state of Virginia. It does not turn to the northeast and of course neither does the 850 low or the surface Low. The reason for this is that the midday GFS sees another system upstream which is acting as a Kicker forcing this system to slide East off the coast.
http://www.wxrisk.com/MODELFOLDERS/today/COMP.jpg

Next image is the 850 Low track with the RED dot the approximate position of 850 low. And as you can see this is a great track for Northern Virginia Maryland Southern Pennsylvania New Jersey and perhaps as far north as New York City and Southern Long Island but that's assuming that it stays cold at all levels of atmosphere. Again note how the model does not turn the system up the coast but essentially tracks it off in a due easterly direction.
http://www.wxrisk.com/MODELFOLDERS/today/COMP1.jpg

Now I'm not saying that the midday Thursday GFS is correct that simply with the model showing.

That being said there are some things to talk about. First the arctic HIGH that comes down from western Canada into the Plains and Midwest is an impressive 10044 MB HIGH The climo of significant or major East Coast snowstorms is such that large arctic High pressure systems such as the one we are going to see tend to favor East Coast Low-pressure development. Second the reason why we do not keep cold air in place is because of the unfavorable pattern we have 500 mb over eastern Canada and Greenland. This is a textbook case for all you out there to understand why the upper air patterns over North America are so vital keeping a ALL snow event the Northeast corner. In this case we don't have the features that we want to see typically look with all snow event. According to the model and again this is just the best early guess ... there is no 50/ 50 low over or near Newfoundland Canada. There is no high Lat blocking over Northeastern Canada or Greenland.

Because of this lack unfavorable upper-level pattern over eastern Canada and Greenland to large arctic High and its neck that extends into England breaks down as the secondary Low develops on the Northeast coast of North Carolina. This allows a southeast wind to develop until the coastal Low finally kicks and thus the changeover to rain along the I-95 Corridor from Richmond all the way to NYC.

Now all this means is that the odds are not favorable for an all snow event for the I-95 big cities but it's quite possible that is this set up that the big cities could see significant snow before changes over and given the fact as early December one should not look a gifted worsen the mouth.