Holston_River_Rambler

Thought I'd check out the Euro soundings to see how it is handling the airmass after the front and I think it gave me a new weenie rule! If the sounding shows the dewpoint being higher than the air temperature, something could be off with the way the model is rendering that particular area:

One of the GFS soundings is pretty awesome in one of the pockets of heavy snow (this one near Monticello KY): 11000' DGZ fully saturated.

CMC still holding strong overnight with the relaxation only idea GEFS looks toasty: EPS: EPS looks like a compromise between the GEFS and GEPS, at least to me.

I can't tell if the GFS is showing a wave running the front to produce the anafrontal precip, or if it is one of those deals where the GFS still thinks there's precip after the front moves through. I think what we want at this point is something like Christmas 2020: You can see the shortwave throwing precip back as the precip shield takes on that weird stretched S shape: I went back to the Dandrige Dollop storm thread and found some of the H5 vort maps to see how that one played out. Sorry these are random snap shots of the models depiction of that storms evolution, but that was all I could find: Euro from about 130 hrs out: CMC from around 144 hrs out: RGEM from about 80 hrs out: Each of those has some indication of a secondary vort lobe that spawns the leeside low. This one is just a wrecking ball, but there are small individual vort whisps that keep some divergence after the arctic air arrives: Euro looks less good with regards to that potential: GFS also has us in *gasp* not the right entrance region of a jet streak, but the left exit (also favorable for upper divergence and lift): Euro is similar, but a little further north with the jet: Those are probably the differences in the amount of precip each model drops after the front blows through. Apologies if that was too much, but I kind of wanted to work through the what and why of the set up, so I could know have a handle on my own expectations lol. I like the leeside idea and want it to work since it has worked in the past (Dandridge Dollop storm, Christmas 2020), but as of now (admittedly 100 hours out) ensembles aren't too thrilled: GEFS:

Ensembles starting to get the floody look way out there. Jet accelerates over the TN or OH Valley as the mean trough dumps in the center of the US and we land on the right entrance region: EPS: GEFS: Could change on a dime, but we know how we do with rain in a La Nina, so......hopefully it passes through or some blocking modulates it south of us.

I'm with you on this NAO stuff. I've yet to see one that helped much. Maybe that'll change when we get the Magical Moderate maybe Modoki El Nino next year. I think the last time an NAO did much was 2009 - 10? I've only participated on the weather boards for a few years now, but before that when I started people were always looking for them. Apparently they've been very rare over the past decade or so, so maybe 09-10 worked so well that after that it was all people could think of? If everything has to be perfect with them, are really just chasing unicorns like 9-10 and 95-96? Some of y'all are a lot older than me though, so maybe you remember better NAO times. Maybe the AMO has to flip for them to really help?

EPS member 15 as promised in the other thread:

Might as well snow good old EPS member 15 in banter too.

Before I post anything for the snow city maps, check out the spread of the EPS members for the temps on the 23rd (I picked Chatty since it is typically a warmer spot): Elizabethton: Nashville: Chatty: Memphis: London, KY:

I’ll have access in about an hour to the 12z EPS city charts so if I can I’ll post for some of the cities in the forum area.

@Carvers Gap trying to go back to sleep on a friend’s couch in Boone lol. But it was 445 and of course I had to see how the Euro went down after everyone was saying the Icon made a move towards the GFS.

The above was when we wanted the GFS to be wrong about the huge upper low, when the CMC and Euro were showing good upslope for this weekend (i.e. today and tomorrow). CMC at this range for today: GFS for same date range at same initialization time: Actual conditions in Kingsport: Now to be fair the GFS didn't exactly nail the 500mb pattern (trend of runs since that time through 12z today): But maybe there is reason for hope that the GFS isn't totally out in lala land. Cards on the table I'm hugging the GFS for all its worth.

Ehh, it did indeed end up like the CMC camp, despite starting out further west: Big old cold front. But wait, that output looks familiar.....

And the above wasn't meant as a critique of your post @tnweathernut, I just happened to be typing at the same time.

To be fair, it may end up looking closer to the CMC with surface output (haven't looked yet since weathermodels is slow wrt thatoutput), but I'm happy with the energy's trajectory at 12z than what it had at 0z:

12z run is 500 miles west with the energy on 18z 12/22, vs 0z run.

The GFS and the Euro handling the size of he energy and its trajetcory ejecting down the PNA ridge differently, but I think the end result is going to be a step closer to the GFS this time.

I think the Euro is digging a bit more this time. We shall see.

You're a brave poster Wurbus.

Saw a WPC graphic on the MA forum, and thought it was odd that someone bothered to up a dollop of NE TN to 10 - 30% chance of 0.25" liquid equivalent of snow/sleet, instead of the 0 - 10% for the rest of the area (outside the Smokeys). 30 - 50% in the Smokeys makes sense. Leeside of the Eastman Bubble enhancement?

It may mean absolutely nothing with this next system, but the GFS was the first to jump back north with the huge upper low this weekend that the CMC and Euro had been dropping over us to give a good upslope event. Looks like it did that about the range we have for the 23rd system. Euro and CMC eventually corrected that way. That being said 6z GFS jumped back a touch north with the the amplitude of the energy's dive toward the SE. It's all just going to depend on the angle and steepness of the PNA ridge the vort runs down. Still a nice clipper though for some forum areas. But then it gives us this more chances after that.

Ok, I will be in Western NC for the next two days. Do I need to recreate a scene from Twister for the 12/23 possibility, or will that jinx it? Does being at or above 850 MB help or hurt? I'm willing to humiliatingly abase myself in gif format for the high end of this potential system.

EPS temp charts for 12z: I think one member has a high of 0 and a low of -5 on 12/23. Man, what an ensemble mean though for that day!

Here's the magical overnight Euro run: That sucker is a hair's breadth from being a mythical storm. Scenario: SE ridge flexes just enough to make the initial vort amp a bit more as it moves over the NW Gulf. PNA ridge pumps up enough to push the main vort, essentially a TPV lobe, on a track that pushes it from KS --> OK --> Louisiana. That baroclinic zone would make a storm that we would never forget. As it stands, here is the pretty output from last nights run: Wind chills: Kuchera snowfall: Of course the Euro has, over the past couple of years since its most recent upgrades, tended to overamp storms at this range. 6z GFS OP is basically a non event aside from a few flurries. 0z EPS support the idea of at least som snow for plateau areas to the east: as do the 0z GEFS members:

The rain has absolutely poured here all day today. 2-3 was the WPC call, but I think 3 - 5 might be better once this moves out by 12z tomorrow: Found an otter pond at 3000' in Frozen Head SP, wonder how it will look tomorrow, lol: