Heavy snow discussion from WPC
...Southern Appalachians to the Northeast...
Days 2/3...
The aforementioned trough moving east across the southern Plains
Saturday will cross the far southern Appalachians Saturday night
and turn northeast up the front side of the main trough and off
the Northeastern Seaboard Sunday/Sunday night. Perhaps the 00Z
guidance has brought about a reasonable consensus solution with a
track over the southern Mid-Atlantic Sunday morning, with the
surface low pressure tracking along the Carolina Coast with
typical biases of a faster GFS solution and preference to the
similar 00Z ECMWF/NAM/UKMET. Going forward, the parent wave will
be in the CONUS raob network which will hopefully limit further
track shifts. While track is in better agreement, there is still
thermal and intensity uncertainty. Marginal thermal profiles over
the southern/central Mid-Atlantic likely limits moderate snow
rates to where low level frontogenesis and associated mesoscale
bands set up. These are currently progged over southeast VA to the
southern Delmarva Saturday night into Sunday morning. Strong jet
dynamics allow the low to quickly shift northeast off the
Northeastern Seaboard Sunday into Sunday night with some northern
stream trough supporting mainly light snow into interior New
England Sunday afternoon/evening. Day 2.5 snow probabilities for 2
or more inches are low to moderate from the southern Appalachians
all the way through central New England and moderate for New
England on Day 3. The heaviest snow is likely to be in the
southern Appalachians with low Day 2 probabilities for 4 or more
inches over southwest VA and western NC and more low probabilities
across New England on Day 3.