The rain should taper off tomorrow morning. However expect drizzle to linger - - then the real fun starts.
The deal is this. The reason it has rained so much the past 2 days is because of a stalled out frontal boundary draped over our region. Well - - tomorrow, expect this to sink southward into SC. However, another "ripple" of energy will ride along this Thursday - - not only that, but a piece of upper level energy will interact with this "exploding" an enhanced of heavy precipitation wherever these two interact. The big question has been where exactly this occurs. Most models have showed this happening well south of us all week. However, as the piece of upper level energy has gotten closer, and entered the SW US, the models are able to actually "see it" and interpret it into their output. This is evident in both the GFS and NAM runs as of midnight today. Both drop a widespread 6-12" of snow everywhere from Boone - Winston Salem - Lynchburg - Roanoke - Bluefield - Bristol and EVERYWHERE in between. Even a possiblity of significant snows making it into the DC Metro area.
The result is this:
Above we can see how the negativeness of the trough explodes precip over SWVA and NWNC. This would be hard and fast - - probably close to an 1" of qpf in 6-10 hours. This is not your typical low that tracks from Alabama up the coast. This is a piece of Upper Level energy interacting with a stalled out front, These aren't too typical. One great example is March of 09. If you can remember that it dropped snow from Memphis to our area. About 6-12". Most of this however came in a 6-8 hour period when the "comma head" moved through. This is an area of upper level energy that is usually really strong and intense. Add to that - - it is even further enhanced by a Jet Streak in the atmosphere.
The nature of the energy is such that it is fast and intense. Not broad and drawn out. This will be in and out in 12 hours. But the amount of energy is really quite astonishing resulting in these high totals. Add to that the rate at which some of this precip could be falling, and we would have a major disruptive snostorm. Quite litterally, if this evenings model runs verify, we will see a major, possibly crippling snowstorm Thursday in the Southern Appalachians.
You ask Zach, well why isn't anyone talking about this? Frankly - - if you have been following some private mets - - they have been for days. But the major shift today is a bit to the north. This makes sense as the energy is now in the SW US and the models now have an actual sampling of atmospheric energy to put into their data.
The area I expect to have the *best* chance / highest chance at seeing the most snow will be between the I64 and I40 cooridors. Believe someone in here will see double digit snows. Further north of 64, the snow should push, but do not believe it will be as steady or as intense.
Want to see the data tomorrow before going ALL In - - but will say with high confidence expect at least SOME snow Thursday across the area. The potential for a HEAVY snow is there - - but not set in stone yet. As with any forecast there is bust potential, but I feel pretty good about this setup to at least see something. Will update again tomorrow afternoon with a snow map.