The start of the event could be as early as Monday night after midnight, but is more likely around daybreak Tuesday, or even as late as midday Tuesday...all details worked out later, and "how much"...etc...
Technical Discussion...
This is my first guess, but don't hold me to it. I did a lot of consideration, but still any track could still verify. But usually this season, the models have been too weak with precip and not far enough north, so I begin in Texas, although didn't concentrate west of the Miss. River. The GFS has a good looking 5H look, but probably too broad and fast, but good at 850, whereas the NAM is superb looking, maybe too bullish there. As time marches on, I think the moisture should be much, much further north in Arkansas and Mississippi than shown but the surface reflection still weak, but strengthening rapidly as it approaches the Florida Panhandle. The Shortwave in the Midwest will begin to draw the n. Gulf low further north than most models currently have, a trend reflected all season long, so I think models will catch onto this from here on out. The one thing keeping it from getting too far north is the strong Northeast system which will be slowly pulling away, but all models have it pulling away, and have yet to adjust for a further north track.
By 84 hours to 96 hours (Tues. AM), most models have a very healthy look to the 5H low in the Gulf and it bows its omega field northward into n. Alabama and Georgia and western SC. This is where the snowfall really begins to break out, much like what happened with the mid February event. This time however, rates in the snowgrowth region are much higher and flakes much larger, with some nickel sized dendrites, and the incoming s/w on all models looks to be phasing in helping with the northward lurch of moisture. Some areas will be rain to start and the rain snow line will be difficult to know just yet, but Atlanta to the 85 corridor looks pretty snowy as long as this scenario plays out.
During this pivoting process the surface low hooks sowly across northeast Florida and comes offshore between Jax and SAV and deepens extremely rapidly. This will keep an easterly mid level deformation axis nearly stalled across the western Carolinas and northeast Georgia, while the northern part of SC and most of interior NC begin to snow and the rates here will pick up quickly. Over the easternmost sections of SC the changeover to rain is earlier than over eastern NC , but mostly likely mid level warming comes just inland and mixes or changes to rain , but if the storm develops more offshore, then this region remains mostly snow. Either way, eastern sections go over to snow (and very heavy/wind driven) snow as the storm gains enough lattitude and temps aloft fall on the southwest side of the low. Interior of the Carolinas and now up to central Virginia are in heavy snow, with strong lift from the phasing and lowering heights, with constantly adding 5H energy from incoming vorts into an increasingly negatively tilted system..very unprecedented.
Most models stall this system off the Outer Banks and don't lift it too far along the East Coast, but I'm going with it slowing, but indeed does crawl up the coast and grazes the big cities of the east coast. Once it gains so much lattitude however and hits the residual confluent flow, its squelched and shunted more east, leaving behind an axis of snow that tapers from southwest to northeast. Could be a very big snow in central and eastern Carolinas up to DC and eastern Maryland/se Pa and perhaps Long Island before turning eastward. If the storm deepens more than most models show, and it could, then amounts along 95 could be the same or more than the piedmont and coastal plain regions. Analogs, perhaps a blend of Jan 87 and March 2009 as far as precip overall dileneation. I'm not giving snow amount possibilites, but if the track holds up, with the phasing, then in this particular year, QPF numbers usually go up the closer you get to the event.
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