Holston_River_Rambler

Looks like icepocalypse (ok maybe an exaggeration) over middle and east TN, with snow west. Energy goes negative too early that run. But if it is playing games in the southwest, that could evolve better over time.

You can also see how far south the boundary has made it into the Gulf on that run. That would seem to encourage a low to form pretty far south.

There almost a wall of snow from Canada to the Rio Grande on one frame of this: wow

I just hope it doesn't lift north as the vort kicks out. But it looks like the Pac jet is blasting at the Pac NW and that, along with the departing TPV as a 50/50, could help keep it from gaining latitude. I bet we end up with a massive Miller B, (this run) but we will see.

A lot of energy in the SW and a big old HP, the drama, the drama of it all:

Gonna be fun to watch what happens with the pieces of energy over CA and the Baja:

Hits KY pretty hard with ZR:

Euro has ticked south again with the cold: 850 temps last 3 runs:

The one thing that takes a bit to get used to in looking at those, is that the dashed black lines go up at and angle, so that the temp in at 650 is maybe -5c: (Sorry I picked a slightly different sounding for this image)

Euro is rolling.

Aaaaannnnd I probably spent waayyy too much time on that. Looks like it was answered while I was typing, lol.

We just would have to hope for a deeper press of cold. All the precip starts as snow, but melts as it hits a warm nose. 3 different soundings from the 12z GFS at this frame: one approx at Knoxville, one approx. at Carthage, one at approx. Union City: Each has the characteristic warm nose. (The red line that kind of looks like a person's nose). In the first one (around Knoxville) the nose spends a lot of time above the 0 Celsius line. So the precip begins as snow (the green and the red lines, temp and dewpoint respectively) meet all the way up to around 350 mb (scale on the left side). That means the atmosphere is moist that high up. The little bars on that left side represent forcing and the dashed, bracketed area labelled DGZ is te zone where dendrites (snowflakes) can grow. If there is moisture in that, you have snow. But it falls through the area where the temp is above 0 celsius (32 Farenheit) and so it melts. But notice the temp drops down to 28 at the surface, so you get rain that freezes on contact, no bueno IMO. The second has the same problem, but the are of above freezing is much small, so you get maybe a mix. Some snow flakes might survive, but those that melt re freeze as theyt fall through nearly 5000' of sub freezing air, so you get sleet. Last one is the easiest. Starts as snow and never gets above freezing. You may know some of this already, but wasn't sure based on your questions so apologies if it is too much. We want deeper cold so the snow doesn't have a chance to melt. The High being over the Great Lakes might help some as it would shift everything more east. But nothing is really showing anything like that for now, at least for the window I picked above. That high is sliding down the front range of the Canadian Rockies and will likely move in from the NW. Just a question of how far it makes it.

Snowfall satellite before more clouds move in this AM:

Ukie, FWIW (maybe not much this season) brings the energy out too: sorry for the "loading images" was trying to get the precip map on that one gif too: Other considerations: The NAO has kept the SE ridge squished and models have had trouble with that, but, what happens now as it retrogrades to western Canada? Can the SE ridge flex a little more? Or is it still able to bully the TPV so much that it doesn't matter? We essentially have two cut off pieces of vorticity, one relatively positive and one relatively negative; a cut off high (NAO) and a cut off low (TPV), both vying to determine not just one storm track, but the pattern across a continent. Hi res models should be fun this week!

Looks like the Euro has now gone back to pushing the arctic front through after the first overunning event, however that turns out. I've never seen one while I've been participating on weather forums, so will reserve my judgment on how models deal with them until I've seen a few. I will say the RGEM and the NAM to a lesser extent, continue the overnight trend of pushing the front through more quickly and hitting parts of western TN with some ice. What seems to have happened to the Euro (at least to my eyes) over the last few days is that it's higher resolution (or maybe an AI guess, lol) allowed it to see correctly that the TPV parked over southern Canada would end up mirroring the retrograding NAO and following west into Canada. The GFS and the Canadian caught on to this for a bit yesterday and thus a few "torchy" (as the weenies say) runs. Now, what the Euro also caught on to more quickly, was that the TPV gets so far west that it shears out a chunk which gets pulled west, allowing the main lobe to roll back east. So what looks like a cave, is really just a compromise. Almost ran out of digital crayons on this one, lol. The orange indicates the sheared out piece, the blue the main lobe and a southern stream disturbance, the brown SSJ dist. #2, and the green ssj disturbance #3. 3 opportunities for suppression or interaction, although interaction becomes less likely as we go out in time, but that could also allow for the last one to amplify (as indeed it does late on the Euro run). 6z GFS shows what could happen if the energy circled in orange gets pulled back with the "brown" energy piece: CMC is kind fo a worst case scenario where all that energy travels just in sync enough to keep ice going over west TN for days and days. ICON only out to 120, but looks like the GFS, at least in terms of the "orange" piece getting pulled back in by the "brown" vort.

Elevation made a huge difference here in MoCo. Just 200 feet above my elevation: You can see how close the heavier snow was to the valley floor. 1/4" now and melting fast, even at 1300' here in Mossy Grove.

At least we aren't flooding yet. Though..... The Parallel Euro that hammered Atlanta with snow just a couple of days ago, now gives us a good start: EPS has a few concerning members, but few and far between: Some of that would be snow though, at least for Crossville:

Looks like I was upgraded to a Winter Storm Warning overnight. That's probably the real culprit, lol!

We had the dreaded S winds as the sun set up here last night. It did feel a little colder than last night though. The downslope could have been a part of it, but I suspect it was a boundary layer warm nose that was banking up against the plateau. I know that sounds weird, but the Hi Res models were showing me just barely on the edge of it. NAM 3km (just as an example of what I was worried about): Just heard on the News a report of 4 inches in Wartburg. I may drive up that way later this AM to see where the line ended up being.

Half an inch paste job here. Raining now, lol.

Oh lawd! Just woke up! Rain snow mix but it must have poured snow for a few. Slushy half inch on grassy surfaces.

100% a "let's go look in the floodlight and guess" game, but looks like snow so far. Precip. rates low at this time.

Come to papa:

Higher DBZ returns aimed right at me. On high grav. beer 3 now. Will update when those returns are overhead.

Some of the enhanced lift looks like it is moving out for now. Gotta wait on that juicy precip. near Huntsville now, at least for us plateau folks.