Carvers Gap

12 RGEM for comparison....

So, the ARW is at 43(out of 48 hours). NE TN folks add a tenth or two more to your run(edi...full run shown). Now, take this model and compare it to what we have seen so far, and what is still to run. So far(with the notable exception of the NAM), this looks very similar. Now, I have seen one storm go horribly, epically wrong in terms of modeling. Charlotte was once forecast to get 4 feet of snow. Short range modeling got all sorts of feedback going as it turned the corner. They got nothing. I made the mistake of sharing that forecast with a friend of mine who works for ESPN. He wasn't happy when that didn't verify. I was scared to death(still am!) I was going to end up on his show for sending him that!!! LOL!!!

It is kind of pick your poison at this juncture. Ice or snow. Could all of that change? Sure. I would think by 18z, we have a much better picture. I hope so, because that is only 12 hours before the event starts in E TN(southern Plateau).

The 12z ARW is rock solid compared to its 0z run...remarkably similar.

NE TN peeps, the storm isn't even too our area on this model. Just to illustrate the 12z ARW run that is underway.

The 12z ARW is having none(and I mean none) of what the NAM is having. Ice doesn't even reach the southern TN state line on that model so far....and it is about halfway across the state so far.

One additional thought. It also could be the northern jog that has occurred all winter at the last minute. The problem? Modeling during the last 12 hours last weekend....came back south. Again, let's see if it has support. The alternative option (ice) would be rough. That could make rush hour a complete nightmare on the eastern side of the state.

I think we wait to see the rest of the 12z suite before passing a verdict. To me, it looks too wound up. It looks like feedback. That is a bias of that model. The bigger problem is that the 12z NAM is by far the most significant winter scenario we have seen in modeling this week. The suck factor would be off the charts. If it isn't feedback, I do think it is because the storm has been sampled better. It started jumping around as soon as that northern vortex came on board.

12z 3K NAM and 12z 12k NAM:

The 3k NAM managed 6" of sleet somehwere in the Upstate or SW NC. That just seems way too wound up. Seems like feedback.

The NAM is stubborn, and it that is what is concerning. RIght now it seems our choices are either snow or ice or both. That run is a far more significant winter storm (in regards to impacts) than anything that has been modeled this week. If that is the trend, that is an icy trend and a concern. IMHO, that is a winter storm no matter how one slices it.

Looks like whatever is going to fall will be frozen. Most of that falls at night in E TN. That 12z NAM run would be crippling. Let's hope folks get enough warning - if that is the case. That is 100x worse than 3-7" of snow.

That is an ice storm.

If school systems are in session(assuming the 12k NAM is correct) when that hits...everybody is walking home or stuck.

In may ways, the 12z NAM is the worst case scenario in terms of long term impacts.

Either way, the 12z NAM is a significant winter storm for pretty much the entire forum. Those amounts will turn out the lights if they verify.

3.5" of sleet in northern Alabama. I just don't see that being realistic. Maybe it will be, but it just seems a bit "off" compared to even its previous runs which seemed a bit off.

Here you go, @matt9697. I took a screenshot of the ensembles when they "hang up" or pause. Looks like the 20th or 21st are a window for overruning. If this look continues for several days, I would be surprised for their not to be some type of event like that. Lots of cold and a little bit of SER.

Yes, we have some commentary in the January thread. As of last night, that signal was there. I haven't checked this morning. I would suspect that is still there unless there has been some sort of overnight flip(which could happen at this range).

The trade right now might be snowstorm for ice storm for some areas. Oof.

The HOT donuts sign has returned for this thread. Now, back to model watching for me. I really don't see a ton of changes from overnight modeling. There is an ebb and flow with each model run. We have seen that overnight. MRX correctly noted (as did all of us as we watched it roll in!) that the 3k NAM is a notable outlier. But it scores a coup enough of the time that it probably should be factored, especially if you make money doing this for a living. The 6z 12k NAM is noticeably less amped, and thus, its snowfall totals sharply increased. It is now the 3k NAM vs all comers. Get your popcorn ready. Who knows what this day will bring or what model trends will be presented? But at least the answer to that question is that today has promise in that it won't be boring.

Man, I could easily be wrong, but with the 6z 12k NAM coming back onboard....the 3k might come back around as well.

I just want to know if we can incorporate that sensor data into our weather models.

Anyone can make a correct forecast if they wait until the event is under way. At that point it really isn't a even a forecast product, but a statement of the obvious.

I don't want my comments to come across as prideful. I know they have a model which has gone rogue(3k NAM). If I got paid to do this, it would give me pause as well. (The 12k NAM at 6z is now back in the winter storm camp). I understand the call, and respect them as professionals. A watch is appropriate(for now) for the eastern 1/3 of the state - for now. However, they need to understand that they have already busted twice this week with little acknowledgement (that I know of) of those errors. And yes, errors do happen in weather. It just goes with the territory. But the morning disco today seemed a bit preachy in spots, bordering on talking down to folks. I could do without that. They also need to understand there are many, many decisions made with their products(timing, impacts, amounts, significance) in mind. If they are right on this one, they will be 1 for 3 this week. I say this often. Luck cannot be part of effective safety protocol.