Holston_River_Rambler

Thanks @Stovepipe your posts were one of the reason I joined this community, so you are much appreciated!

The NAM, it do be running. Shall we extrapolate?

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.

Here's Pivotal's precip output:

TBH the 850s look pretty doggone similar to me.

12z run Sunday AM: 18z run Sunday AM: Looks a little stronger, so it could wash out the slightly south tick

Just a touch further SE with the center of the energy at hour 78.

Looks like a smidge more confluence over NE on the 18z Euro an I mean a smidge. It is out to 66 hours so far.

12z GFS: 18z GFS:

Here's what I'm seeing at COD's website. \ I wasn't around for the 12z GFS, but to me that seems to be a step in the right direction.

IMO this won't be a full cave to the Euro, but a decent step in that direction, just long enough for the 0z Euro to come in more like the 12z GFS, lol.

At hour 63 it is almost a state further south and faster than 12z, at least based on the H5 vorts on COD's website

RGEM says no gulf lows for you:

A few more 15z SREF members see snow in Crossville than at 9z. I guess that's something.

The way this storm has bounced, the 6z RGEM Saturday is going to run the GFS's attempted winning field goal back for a touchdown.

Didn't the CMC try to ice our kicker earlier today?

EPS members at hr 120:

12z EPS low locations: In meetings this AM, did I miss all the fun, lol?

Looking at the 850s, it is allowing for a little better entrenchment of the cold air before the system and the surface low is a few millibars weaker at hour 90 of the 6z Euro.

Not sure it will mean much in the long run, but the 6z Euro is a little bit more positively tilted, a little bit weaker with the energy, after it interacts a touch more with the upper low off of California.

One of the NC mountains folks just posted that there was a RECON plane sent to throw some dropsondes into the atmospheric river and it also threw some soundings at our energy for the weekend system.

TBH going back and looking at the 12z CMC it looks quite bit like the 18z GEFS with its slp placement.

Here's a loop of the GEFS lows. The small lps and hps are members and the big Hs and Ls are the means:

Looks like the GEFS lows are about half north and half south: With the mean a touch south of the OP.

I think in the case of our area (specifically central parts of the eastern great valley), we want a low to pop around New Orleans or Mobile and make a run at Cape Hatteras. TBH we don't want any sort of a hand off, since even if it was cold, that would hurt any TROWL/ deform band as the hand off occurs.