fIRST THE LOW ON THE FRONT this sunday and Monday
My view is this: Your views may be different.
the euro has the low tracking the same way for at least 3 runs now as does the 00 12Z UKMET last several GFS ETA etc
Because this Low on the arctic front develops sooooo soon The SE ridge is Still too strong at 60 -72hrs so the Low IMO is NOT going to track AT or S of the Ohio river... and it will pass close to PIT and BGM
The cold air may get into central Ohio but the Low should drive the front back North OR at Least warm up aloft so that the snow at the start turns to Ice.... (FRZ RN OR IP)
PIT looks like Ice to rain....
IF the cold air gets into New england then this Low can bring some snow to ice to rain -- mainly OR all rain over NYC BOS PVD ... assuming the Low DOES tack over BGM and between ALB and POU
REMEMBER south of the low 850 temps are +12 C over VA so the warm air is extreme
a few days ago I made a post that to get the cold air depp into the eastern US after the cold front passage Jan 5 we needed a -NAO and or +PNA
IF we assume the 18z GFS the 12z GFS ensembles and the THURS day 7 and day 8-10 Mean are reasonably accurate
thoise tweo things are achieved.
The overall pattern is very promising for a major historic snowstorm over the eastern US--- equal to PD2 exceeding DEC 30 2002 (which for many was a miss) and equal to a Kocin event like March 93 or Jan 96
Now that I have your attention.... Lets be clear. First This MECS/ SECS threat is not in the BIG sense related to the synoptic question I have as to how long the overall COLD pattern lasts... there have been many winters which as a rule were fairly mild but had good snow events in them when the pattern turned cold
NEXT Yes 18Z GFS and the day 8-10 EURO is screaming Massive snowstorm Jan 12-14 time frame IF TAKEN VERBATIM
http://www.sca.uqam.ca/models/ecmwf_amer/PN_GZ_240_0500.html

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_500_216s.gif
That being said lets be careful.
First we are EXTRAPOLATING on MODEL at day 10!!!!!!!
on a s/w that Might or might not be there
and might or might not crash into the west coast
and might or might not hold together!!!
WE are also assuming that the 50/50 Low is text book perfect as shown k.... and that the NAO goes severely NEG
Then we have to assume the PNA forms !!!
Then there is the Pacific Jet which COULD Blow things apart faster than you can say A-10 warthog attack plane.
I will remain as even keel as I can for this event and see where it takes us...