Carvers Gap

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.

Yep. Very true. Also, a northwest jog has been discussed for several days. It is one reason I try not to be too emotional about modeling. The wx is gonna do what it is gonna do...and not a thing I can do about it but observe, predict, and revise...and enjoy the process. This is a fun hobby for the most part.

Good deal. After so many years of Memphis having to sit and watch others get snow, you all are on the books with yet another one! It has been a good 4 years for you all generally.

18z RGEM...surface temps are an issue for Chattanooga as is decreased overall precip. Sleet and ZR mixed w/ rain and snow. Not sure I buy that, but the WxBell algorithm has it.

Kuchera for 18z RGEM (left) and for side-by-side comparison w/ 12z. Slight jog northwest, but pretty massive expansion of precip field which we are seeing across modeling.

The RGEM really beefed up amounts. The 18z RGEM brings the entry point in the forum area slightly north of 12z. It still flattens the system as it heads eastward. That slight changes increases amounts over middle TN. Last minute northwest trends are not uncommon. We actually "stole" a system many years ago from North Carolina on a 48 hour trend at the last minute. If the cold in middle TN is stronger than expected, there will be a likely limit as to how far it can trend northward. More than anything we are seeing an expansion of the northern precip shield vs a major movement of the snow demarcation line to the south. About a one county jog northwestward for the southern extent of snow. Also to account, there is a certain amount of ebb and flow noise in modeling.

Awesome, man! How much are the predicting for your area, AMZ?

The 20z RAP at 21h looks nearly identical to the 18z RGEM at the equivalent time.

So, my pessimism aside, if modeling bumps up totals at 18z, it likely means they are playing catch-up. If you like lots of snow, that is a good thing...wherever this sets up. The best winter storms rarely stop increasing totals, even during the last run prior to the event. The 18z ICON is a good trend it appears. Also, of note, El Nino systems tend to overperform at times.

We were 7 degrees over projected highs at TRI today.