RB's Video for the January 4-5th Possible Snow Event

Sorry it's a little long, but I tried to explain things as much as possible so everybody could understand it. I do have a few things to add/revise from the video:

1. The low-level circulation should follow the coastal thermal gradient, as that is where there will be the natural lowest pressures before the storm develops. Once the lead energy begins approaching the East Coast, that will induce the greatest pressure falls along that boundary, and should create pathway of lower pressures for the actual circulation to follow.

2. Even on the EURO Op, if you look at the vorticity structure, it still supports some degree of precipitation making it as far west as about State College, PA (if you notice when the third piece of energy starts interacting, there's a streak of energy that extends from the main negatively tilting trough on the East Coast back toward the Ohio Valley and then east-northeastward through PA - that's the back edge of the precip shield. This is also supported by the developing jet structures, where the streak over New England continues to trend stronger and further westward, which will draw and expand the precipitation shield further northwestward.

3. With what is still a progressive pattern, that argues for an earlier tilting lead trough on its own, since it will not want to keep digging/progressing on the same latitude - it wants to get up and out, but the only way it can do that, as explained, is to change its axial tilt. This will further back the flow/raise heights ahead of it. However, the factors outlined in the video will still allow the second and (correction here: also the third piece of energy) to dig faster and be stronger.

4. Models tend to largely underestimate the the diabatic heat release with systems that have so much energy and convection associated with them. As a result, this underestimation results in heights ahead of the "main show" to be represented as being lower (less ridging) than what actually occurs (in conjunction with the convective feedback I mentioned in the video), as all of the latent heat release feeds into the ridge downstream, thus allowing it to amplify better and quicker than modeling, especially globals, can resolve, even up to the event. This should also lead to further westward shifts, as this becomes realized, the ridge is modeled stronger, and the flow begins to back and have a stronger easterly component sooner.

Enjoy, and any questions, comments, concerns, please leave them here (or in the storm thread) and I will do my best to answer them!!

Just for clarity's sake, this video was made prior to last night's 00z runs, and I have yet to assess the overnight suites.

https://drive.google.com/open?id=1M6lE8WhomsQL4a0K74-LU-qsQQAUqctr