DEC 25-26 Low tracks WEST on 0z Data then 12z GFS shifts it back east

No... no... No and No.

I have said before and I will say it again at least a hundred more times in this winter season. You do not get winter storms -- SEC MECS HECS -- on the East Coast simply because a weather Model shows a large 500 low somewhere along the coast. You get them by having certain features which ACTUALLY exists in the atmosphere -- NOT on a model -- synoptically BEFORE the event actually begins. Oh sure occasionally you get the rare synoptic scale event which are so dynamically strong that they can alter things on a regional synoptic scale but for the most part that really doesn't happen.

In a nutshell the 12z GFS Thursday run for this event over the eastern US on the 26th is not vaiable. Let me explain why.

Yesterday I mentioned how I did NOT like the 12z WED runs with regard to the 500 Low coming out of the Southwest and tracking through the Gulf Coast and up the East Coast. This is what we saw with a medium-range models last week on the system now leaving the Plains moving into the Midwest that produced the blizzard conditions in Colorado Western Kansas the western Nebraska.

Originally that system was supposed to track to the East coast and did not because the Models misdiagnosed or did not see another shortwave that dropped in and cause these two systems to phase much further to the West. This the issue that I expressed yesterday.

The 0z data on the operational GFS Canadian British and European models all supported this westward trend. The northern shortwave is coming in stronger on the 0z model runs as we get closer to the event and this results in the phase betwewn the northern s/w and the closed 5h low coming aross TX to occur MUCH earlier... Not east of the Mississippi River as we saw yesterday but now WEST of the Mississippi River almost in the Plains. This results in the system tracking much further to the West which is what I feared was going to happen
http://www.meteo.psu.edu/~gadomski/ECMWF_0z/f96.gif

http://www.meteo.psu.edu/~gadomski/ECMWF_0z/f120.gif

http://weatheroffice.ec.gc.ca/data/model_forecast/134_50.gif

Then along came the silly 12z operational GFS which is back to its old tricks. Now that model is developing a 500 s/w over se Canada at 96 hrs into a closed 500 low over southeastern Canada near Newfoundland -- a true 50/50 Low -- whereas on the data from 6z and 0z operational GFS did not show that!!!.
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/fp0_096.shtml
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/12/fp0_120.shtml

Because we now have a 500 low that's closed off near Newfoundland the two systems still begin to phase over the Mississippi Valley but now is forced further to the south and east and has result the whole system is shoved back to the east including the critically important 850 Low.

I do not believe that the shortwave moving through southeastern Canada at 96 hrs is going to close off. I think the 12z Thursday op GFS model is overdoing it on this system and this bogus development results in the model screwing up the entire event. There is NOTHING over Greenland and / or the N central Atlantic that would cause that shortwave to slowdown and close off over Newfoundland .

Even if you were to take the 12z to heart the low level warming and the inland track of the 850 low is NOT good for coastal areas from PHL to BOS. The 12z GFS taken verbatim can bring a decent snow inland over NY state and New England...

I think the entire solution here from 96 to 144 hours is bogus. The 12z CMC shows NO such closed 500 Low over se Canada at 120 hrs
http://weatheroffice.ec.gc.ca/data/model_forecast/colour_images/12_054_G1_north@america@zoomout_I_4PAN_CLASSIC@012_120.jpg

and the phase is too far for east coast fans to wise for snow.
http://weatheroffice.ec.gc.ca/data/model_forecast/colour_images/12_054_G1_north@america@zoomout_I_4PAN_CLASSIC@012_132.jpg

My view -- I still see this as a Appalachian snow event MAYBE... and even that may be too far east. I like the 0z euro idea track alot and given the numner of Lows we seen track through the Plains and Midwest this solution as shown by the 0z Ecmwf matches the seasonal trend

Looks like we have another Major trough moving through the Midwest -- with no real cold air -- 12/30-31
http://www.meteo.psu.edu/~gadomski/ENSHGT_12z/f216.html