I think that 540 line is just more of a guideline, than a hard and fast rule. That being said, climatologically it will be hard to deal with the downsloping for the eastern valley and even me on the plateau off of frozen head with a ENE and NE wind.
MRX had good points in their PM disco:
"In [my] experience many times Miller B type events, and the resultant snowfall totals are not handled by the long range models especially well due to low topography resolution. One of the biggest things they seem to incorrectly forecast is the strong downsloping that occurs with these systems. The downsloping then results in higher surface/low level temperatures and really eats away at snowfall totals with a slightly warmer atmosphere. Combine this with many of the deterministic models predicting the heaviest snowfall to occur during the daytime hours... and the only slightly below freezing temperatures overnight... and temperatures possibly reaching into the 40`s in the Valley during the day on Saturday/Sunday... It all leads to heavy skepticism in some of the high snowfall totals that some of the deterministic and ensemble amounts being depicted."
In the main thread, Jeff also noted that even NWS offices in West Virginia were worried about a warm nose.
For my part, I hate anything that even resembles a Miller B. That low is trying to find a thermal gradient to use as a transfer pathway and the lower elevations of East TN create a warm pocket for some part of that low to go.
In my limited experience, Miller Bs have been STJ systems. I know that isn't always part of the KU definition, but for us in the east TN valley, ANYTHING that sends a piece of low pressure up the valley as the energy transfers to the coast, might as well be the same. I can understand people further north using the A/B hybrid distinction, but it really doesn't matter if you live from Chattanooga to Morristown, IMO. This is not a STJ system though.
The angle of attack for the energy is unusual for us and there have been soooo many shifts, some dramatic, in NWP, over the past few days. That normally suggests ensembles are more useful in unusual situations like this, but we also have to consider that ensembles are compounded iterative differences of initialization conditions, while we're lookin for frinkin' reality. Ensembles suggest, but don't precisely foretell. To me, the OPs have led ensembles for this system, and that also suggests that this is an unusual set up. We've seen a few model cycles where the OP ripped the ensembles out of their happy median and said basically "Nope, we going this way." The smoothed mean can't account for realtime conditions and any small bird fart perturbation chaotically shifts the NWP outcome. I guess all I can say is La Nina. Fast flow in a chaotic medium = chaotic results.
One thing I found of interest on the 18z Euro were the Dewpoints:
That's some cold dry air trying to filter over the mts and making some headway at TRI. PSU in the MA forum was commenting on some analogues and says that this antecedent airmass is the coldest among those analogues. Now, they are closer to the HP in the mid Atlantic, so that may not apply here, but it is something to think about.
I think this storm has one or two more tricks up its sleeve before it's finished, but I am also prepared for my heaping helping of a warm nose, served piping hot, if that happens.
