ILMRoss

Good luck to everyone! After growing up in Wilmington and attending NCSU, it's been a breath of fresh air to track a... less stressful storm here. I wish the same luck to everyone right on that edge! Thank you for your reports! I kept a steady eye on this thread and I was able to sound off a few obs during my 11 PM newscast. There's no such thing as too many obs, so if you feel obliged to report something, post it!!

Wow, the FV3 GFS has absolutely shown killer consistency, right to the end. If this storm follows it's script, what a coup! Nice to have a trustworthy (at times) tool in the the toolbox, or at least moreso than the current iteration of the GFS.

From what I understand thunderstorms oriented perpendicular to the storm track essentially act as a firehouse of moisture into a system, whereas storms oriented parallel to the storm track can basically act to cut off the conveyor belt of moisture by disturbing the inflow into the storm.

I like cranky, and I think he can have some moments of brilliance, but often I find his reasoning to be oversimplified... like right here. Gee, if it were as easy as looking at cirrus clouds, I'd be out of a job right now.

RGEM has a sharper, more negatively tilted wave as early as 36 hours from now, which is causing the stronger solution. I don't know much about how the RGEM handles synoptics but I wouldn't attribute the run to mishandling of convection.

My guess is that the suppression trend is partly tied to this: the trend is for the ULL to "landfall" into Baja California as a more and more positively tilted wave. This positive tilt has ramifications downstream for its orientation, how amp the wave gets, and where some temperature profiles set up because a more negative tilt can raise heights downstream.

Something I’d watch out for in this next suite is cyclogenesis along the Atlantic- so far not a single global has represented this well to my eye. The mesoscale models look more believable. Here’s what I mean: Cyclogenesis is favored to occur in areas where there’s already a distinct low level vorticity axis (think: frontal boundary! “Low level vorticity axis” sounds like an intimidating weather term but it’s really just represents a wind shift!) In CAD regimes, there’s always a super distinct axis just off the coast between the CAD Airmass and the coastal front. Thus, as that area has some lift imparted on it, you’d expect pressures to drop and cyclogenesis to initiate. The globals don’t show this. Here’s the GFS: it has not signature along the Gulf Stream at all... and I’m not sure I buy that. Here is the nam in comparison at the same time: In the nam, there’s a much more distinct signature of this taking affect, and this represents what “supposed” to occur in this scenario. I think this is helping toss everything more northward in the NAM. Now, obviously, meteorology doesn’t always bend towards what’s “supposed” to happen, as any seasoned weather enthusiast knows. That being said, I wouldn’t be surprised to see a “CAM vs Global” battle emerge today as more CAMs get in range. Lastly- CAM = convection allowing model- think NAM, RGEM, HRRR, etc. They don’t have to parametize convection with their higher resolution. .

All I’m going to say is, Fish loves ensembles, and Fish loves certainty, and the ironclad nature of 1 inch + totals on the ensembles have probably weighed on that team.

CAD actually warms the other side of the Apps. We’re all familiar with how cold, dense air “piles up” on our side, creating CAD. However, on the Tennessee side, there’s all of the sudden much less air making it over the mountain, which lowers air pressure (why you see an inverted trough here) and ultimately warms the area.

I spoke a little too soon, next frame the r/s line makes a bit of a comeback, almost back to the previous run

Solid 40 mile shift N with r/s line, weaker high here.

18z FV3 already looking like a pure weenie run

Wouldn't be surprised if there's a diminished gradient because more members are throwing some of that front end thump further east. that initial finger of precip extending ahead of the storm can be a doozy. I would still expect the main rain/sleet line to developed somewhere along RDU/CLT during warmest portion of storm

Really I wouldn't even focus on p-types much right now at all, not until the NAM-3km and RGEM has taken a couple of cracks at this storm. Until then, a rough guideline would be to take the modeled 850 0C line and imagine another line 50-75 miles north of that... there's your sleet zone between those lines. We're still talking NC snow, lol.

FV3 is fine, the low is going to gravitate towards the Huntsville/Knoxville area a little before the transfer because of the CAD forming lower pressures on the OTHER side of the Apps... One more thing to think about is the overall pressure field remains similar, but that little "L" icon is going to shift. It's there because Levi's or whoever's code puts that L at every local minimum... and in a transfer like this, that could be a lot of areas! Run to run, the "L" could jump by hundreds of miles, but in the grand scheme of things, it's probably not a big shift. It's a psychological thing! Be careful!