Carvers Gap

One other note on using deterministic global models once inside of 36 hours, they don't have the ability to dial things in like short range models as they lack the hi-res ability to do it. But somehow, they still outperformed the mess scale models IMHO. The ultra hi-res, radar based models did well... So far(and this is like keeping score at halftime), I would rank globals in this order: 1. ICON 2. GFS/Euro 3. CMC(though the CMC picked up on mixing along the mountains first...) Short range modeling(1-2 days out): ....No winners so far. They were all bad. I will probably use global deterministic runs in the future and then switch to RAP/HRRR at the last minute. GFS trends were money at the last minute. Models inside of 24 hours: 1. RAP - for middle and west TN. Not great E TN. But it picked up the expansion of the precip shield northward. 2. HRRR ***The NBM will win this. I don't have it ranked as it is technically not a model, but blends other models. It will be my go-to next time around.***. Each model had its failing and some surprise biases, but the NBM was able to fish out the best outcome IMO.

So far..........The victor will be the later runs of the NBM in my opinion, the ICON in middle and west TN, and track goes to Euro but missed on northern extent of precip(does it have a dry bias???). The GFS absolutely nailed this with its later runs. The Canadian/RGEM package looks sketchy over NE TN. The NAM was terrible - woeful in terms of an amped track. It was bad enough that I won't use it any more. The RGEM probably will win track also but lose on northern precip shields, and lose for Chattanooga. Systems w/ two pulses of snow are notoriously difficult to predict, especially the second. Onsets(bulk fell after dark) of precip helped middle and west TN as precip arrived at night. E TN will be fighting daylight today. In the end, the NBM which blended the modeling probably is going to score the easy win. And it is important to note...Most of this is preliminary as the second half of this has just reached areas north of 40 in the eastern valley. But short range model runs are gutting the west side of this second line - and that is where the NAM likely has met its Waterloo. Knoxville should do really well, and that was on pretty much any model that had breath in its lungs. El Nino systems tend to over perform on the northern precip shield, and this one did yesterday evening and last night as well.

...a WIN for the Euro in E TN for sure w/ the second line. The middle and west precip shield was the error on that model and not the track. The models which were amped with this second wave(E TN) are gonna be wrong, and that includes the NAM. This second wave is very suppressed. The initial wave was about right, but the precip shield was underdone to the north. The NAM whiffed. The HRRR is shifting east with each run. Chattanooga is an exception as the Euro was too SE w/ it.

Snowing in Kingsport pretty good now - high side of moderate.

Very fine flakes of snow are now falling here.

Not trying to one-up Tellico. Here is the entire run. Is it right? IDK. But modeling at 0z has been bumping up numbers, and that gets my attention.

It is even more than that.

Seriously, go look at the GFS.

The 0z GFS is big.

Totals on models at 0z are so far trending upward at 0z for E TN - 3k/12 NAM, ARW, ICON, FV3

For posterity. WSWs for portions of 11 states. That is one cold map. Not to mention the snow in Buffalo and like the fourth coldest NFL playoff game ever in KC yesterday. What a cold snap.

The 0z ARW just went nuts.

Right now we have a metal snowman, an elk, and a one tone woolly bugger working in our favor. Time to bring this home.

On a separate note, there has got to be something off with a station(or programing issue) just to the west of Knoxville. It had 22" of snow and 1.0" of water, and nothing the same around it. It is very visible on the 3K NAM. Anyone know how long that has been an issue? @Daniel Boone, you might be the person to know this.... Or that might be the elk in @Holston_River_Rambler's neighborhood.

The 0z NAM has joined the club for E TN - I think. Whether it is correct in reality? IDK. But it is now in line with other modeling from today's runs.

Are you sending us eastern valley residents a subtle message w/ lots of green east of the Plateau on that thumbnail? LOL.

Jax has a great map. I had this post on deck as he posted. Apologies for the repeat. Here is the comparison to the full run at 15z. Most short run modeling will release a longer run every six hours. So, one trend we are noticing is model totals going up and the precip shield expanding northward. We are probably at the point were 18z is the last run which will have full maps of the event. I am also attaching the set-up so that we can look back for similar looks in the future. Looks like we managed a storm setup w/ a high in the Aleutians but a -EPO and strongly negative AO and NAO. Trough/storm is easy of Hawaii.

Never been my strong point!!!! LOL.

Yeah, it does. Chattanooga is in the mix as well.

@tnweathernutor @TellicoWxor @John1122 or @BNAwx.......I would think there is very little mechanism to bring WAA northward. Time of day could be an issue if it falls during daylight hours and the front stalls. Dynamic cooling would likely play some part as water evaporates and cools the column. It might be less with this set-up, but not absent. Just a layman's guess.....

18z GFS comparison run to 12z for trends...new is on the left.

The 18z GFS manages to keep Chattanooga on the books. Very, very slight NW jog but massive expansion of precip shield and amounts increased decently.

You know your stuff. It is great to have the board grow. When we started, there were just a handful of us. Now, it is a pretty formidable gathering of people teaching/learning/enjoying a great hobby. It took a bit longer than we expected to grow the place, but it is rocking now.

Some of it is an algorithm issue. Some of it is general precip shield shifted about a county northwest for that model. I don't know what trends on the ground are, so it is going to be super important for folks west of us to post their observations. For now, I am going to ride w/ the NBM - I think. But the NBM will be late to the table if this trends sharply.