Carvers Gap

That map is a winner. SLP over southern Louisiana and Mississippi. A cold hp over the top. That cold front dragging into the Gulf is often a spark as well.

The 12z RGEM is muy bueno.

After all of that warmth to start the month, the cold has erased almost all of it. TRI is only +0.4 with likely four cold days left still to input. TRI should finish BN for temps this month but within the seasonal norm range...which is astounding to me after how warm it was to start the month. It is very difficult to erase 3 days of mid 60s temps in the norms. It very well could bring the overall winter average to almost exactly normal to this date - December and January combined. Some wild swings to be be able to pull that off.

The closer to the spine of the Apps that one lives and north of I40.....that is the sweet spot for now. BTW, that is not me. I am roughly in the same boat as Knoxville in hoping for storm trends. I am on the far west side of TRI.

For sure...This is too finesse for my liking. It may well work out, but the cutoffs for this are going to be rough for some folks. Very steep gradient between snow and no snow in some areas. Just kind of has the feel of one that stops at the NC line w/ some light snow west of the Apps and heavy snow to the East. DC to NC snow axis is generally good in E TN. Hatteras to Boston has given me many headaches.

For TRI folks, the trend on some modeling is that the energy is further west, and that causes the precip to drop south without pivoting over us. That shifts the pivot further south and west. Unfortunately, I think some areas(if this is a true possibility) will be rooting for different trends. At TRI, we do not want this phasing any further west than it is(per the NAM). One whiff scenario for TRI is that the energy phases further west as it drops south. The entire storm pivots under TRI, and then up the coast. For now, the 6z RGEM remains steady w/ its depictions as does the 6z Euro, 6z AIFS, and 6z GFS. The 6z NAM would 100% be a problem for TRI.

I have seen systems like this stop right at the crest of the Apps. I do think we see some light snow from the northern stream. I remain unconvinced this gets enhanced by the Atlantic...for most of E TN (edit). Backing would help prolong the light snow. I think those high end amounts are incredibly unlikely unless that slp shifts to the coast or just inland. I could see far E TN counties benefiting for sure due to orographic lift. This looks like "an east of I81" type of storm - so far. Tomorrow likely dials in this track. Need some big moves overnight for anyone west of the foothills to score more than 1-2" with this.

Bout right there. I rarely get good snows in IMBY from a slp east of Hatteras. I still tend to think this is going to have to be home cooked northern stream energy at the end of the day - IF that is the slp location. But sometimes we get that lee side low which backs precip. For me, this is a little too finesse for my liking. Just need a good ol' fashioned low cranking 50 miles inland. Any energy handoff is almost always a problem for E TN.

Any maps yet?

Deciphering the weather posts of Bouncycorn was not on my bingo card for today.

The 18z EPS had ticked up as has the 18z GEFS FWIW.

My rule of thumb…get the slp west of Cape Hatteras if we want help from the coast in E TN. Otherwise, we need lift from the west slopes of the mountains. I still wouldn’t discount a LSL…anyone see it? Lee side low

And that “should” bring precip with it if other cold winters are used as analogs. I don’t trust the coastal enhancement, but I do like light snow from the northern stream with high ratios. If this turns into a NE blizzard, NE TN and SW VA often finds themselves in that axis even if just light amounts near the genesis of the storm. If DC can end up in the storm, that is usually a good sign for us. Kind of a weirdly displaced Miller B.

Any GoogleAI updates for 12z and/or trends?

Yep. The best that a coastal could do is to back the flow which is basically what the GFS and GEM-para do. I have not looked closely, but I almost wonder if there is a weak slp scooting through the Piedmont or a lee side low(LSL). But really, this is kind of a mix of a clipper and an anafront. Can we get a phase? IDK about that.