Carvers Gap

Canada.

Check out the RGEM at 84. Yes, it is at range and probably way to cold, but wow. Real feel and actual.

What is starting to limit modeling trends is that the entry point into the forum area is northern MS to northern Alabama. Why? It is closer to the actual event, and less spread in modeling. That in turn, begins to limit how far the system can trend northwards. The RGEM is my "go to" from this point forward in the chase...for the eastern valley.

I've been telling ya'll that the jet max is the key for the eastern valley. It is what gives the lift to the system.

Great and helpful post. The nw jog has commenced. One more jog SE and that was gonna be bad. Good trend.

21z NBM...and likely has the lower 12z (further south) suite. I don't think it will have 18z until maybe 3-6 hours from now(1-2 runs). New is on the left.....

LOL. Truth, man! Truth! NBM is the way to go I think for now.

Unless there is a lee side slp in western NC which has been on some recent runs. Then there would be sinking air. However, sometimes a lee side isn't bad.........We have been known to develop lows over TRI during systems like this, and it enhances precip. So many moving parts at a micro level. I do agree that if the cold air gets over the Plateau, there is very little to stop it from quickly reaching the base of the Apps. I would guess most modeling is struggling with the strength of the cold air and under-doing how far it get into the SE. Tellico had a great explanation.

18z on left and 12z on right. The SE trend on modeling has stopped for the most part. That fits previous winter storm tracking. With 24-36 hours to go, that is pretty much normal. Remember that trends are what are important on deterministic runs as well. It is good to compare the current run to previous ones. Notice the eastern edge of precip has been curtailed. Again, I do suspect the jet is enhancing precip over the eastern valley. Some of the off runs(not 12z or 0z) are beefing up precip amounts. If a storm is gonna be a good one, precip will start to increase as modeling gets closer to the even, because they can't catch up. Time to watch for that trend.

Tellico, you really seem like you might have a red tag in your past(met).

What Tellico is mentioning is different IMO. I lived in JC for five years as well - love the upslope events! It isn't really a downslope. It is banking warm air up against the Apps as it gets pushed across the valley. Amazing modeling can even model that TBH.

So it banks the warmer air against the Apps? That is pretty rare. Good catch.

In addition, I read that they are concerned about precip issues along the length of the foothills as well is how I read it.

Models once inside of 36 hours which I normally use in this order for E TN....RGEM, HRRR, 3k NAM. I do watch trends on deterministic models, and ensembles still have a place. NBM of models is good until it can't keep up with trends.

I hear that. LOL. Ice w/ the cold which follows is not good!

You may be right on that. The NAM had weak SLP in north central Georgia off the top of my head. A lee side would make sense.

Again, depends on where one lives. Knoxville is likely gonna be good regardless. TRI folks are on a bit of a snow drought. So permit us a moment of hope. (Chattanooga would be in worse shape in that regard.).

Here is the comparison map for the 18z RGEM (12z on right) and also 18z icing map. Most significant winter storms have mixing issues weather NYC or Boston or here. The entry point into the eastern valley is eastward. TRI's numbers are up. Overall, a pretty steady run.

Slight jog SE w/ the snow line once pace middle TN.

That would depend on where one lives.

The RGEM has less precip and a tic south at 36. And the RGEM is what be had better fear. At this point, I don't trust the NAM at all. NBM is probably the way to go for now.

If the RGEM is still south along w/ the SE jog by the NAM, I am close to saying the NAM is an extreme NW outlier. And the NAM is known for exactly that. Once inside of 36 hours, the NAM flattens. Closer it gets to 48, the more it amps and turns northeast. All eyes on the 18z RGEM which is just now running.

Maybe, but don't base that on a the NAM which is possibly dealing w/ feedback issues. RGEM should roll in a minute. The NAM was so amped it tried to bring a slp into the Apps - only the CMC from a few days ago had that. Could it happen? Sure. But for now, no other model has anything even remotely close to its recent solutions.

The easy way to spot feedback on the NAM is to find where it goes crazy w/ precip and/or snowfall. Notice that 12z has been softened a bit in E KY, and the line of precip appropriately moved southward in response. But...it is still amped there. Good trends for E TN.

18z NAM still looks too amped. It gets anywhere near hour 48, and it gets amped. But good to see more precip.