psuhoffman

The storm had a duel wave structure. One down along the gulf and the other along the arctic boundary in the TN valley. The NAM is focusing more on the northern wave and then transfers to a coastal. The others are weaker with the northern wave and don’t really get much precip into our area until the southern wave starts to amplify and turn north.

Look where all the precip is. It’s focused on the northern wave also That won’t end well. Every situation is different. The models have strengths and weaknesses. NAM has more weaknesses than most. If it gets this one right it’s probably more a fluke that it tends to over amp and this specific setup favors a further north storm imo. I think it’s more than just that even. The better vorticity, potential fgen, and baroclinicity are all along the arctic boundary to the north. The bigger mid and upper level forcing is there! IMO it makes more sense in every way for that “wave” to be a little more amplified until the coast where they transfer and consolidate. The NAM (I know not the bed partner I wanted here) just looks like what I picture at the surface when I see the h7 and h5 levels.

If we did that with posts the threads would be a lot less pages

I’m posting in Ji’s thread now on this. I expect more energy focused on the TN valley wave along the arctic front. That would pull everything north and more amplified east of there also.

Ok ya it’s the NAM. I wish it was annything else. But it’s doing what I said the mid and upper level pattern should look like at the surface. Focusing more on the wave among the arctic front which pulls everything north further east. Images from my post last night about what changes I expected to see. Now if we can get everything else to come around maybe. Can’t believe I’m on a team with JB and the NAM. Shoot me now.

What I feel like with JB and NAm as allies

But come on that wall of confluence way up by the VT Canada border is gonna suppress a TPV digging into the upper Midwest and closing off. Isn’t that what always happens?

I stand by the point I’m making. But just because I’ve never seen anything like this doesn’t mean it’s impossible. Not going DT here. It does mean it’s a very rare anomaly and I’m not ready to concede that’s what’s gonna happen but rate anomalies do happen. So just because there hasn’t been a case like this in our upper level records doesn’t mean it can’t or won’t happen. The closer we get the more I have to accept the possibility but I’m holding out until tomorrow night. If we don’t see any hints by the 0z Tuesday runs I’ll put up the white flat

Yea but that’s adjusting a track I never understood. Even when the surface track was perfect for us I was kinda worried about it cutting more. Not to the point we got no snow but enough that the bigger snow ends up NW is us. The track had never aligned with the h5 even when it was looking good for us. So yea I see why the flatter look is shifting the track south. But that’s shifting a track I already didn’t understand why it was so out of alignment with the flow.

So it’s scary that I’m on team JB. But can’t deny he just said what I’ve been saying. lol. Ugh One point I’d contest is 95 Blizzard. That’s typical JB hype. The best h5 analogs I found were secs-MECS level events. The h5 track is actually NW of ideal for those 1983, 1996, 2003, 2010, 2016 type storms. It’s also not oriented like those were. But the weird part is the reason most of the comp storms I saw weren’t bigger along 95 was mixing issues not a miss south. lol. But it’s most definitely not similar to any “miss to our southeast” analog comp.

No just open to being wrong and learning

I think snowstorms are more difficult because you’re adding additional variables because they tend to run along the thermal boundary and involve stream interactions. Summer precip events are almost always convective or frontal passages. I don’t think that’s a good comp. Several years ago I tested this hypothesis and tracked early spring and late fall rain events that more closely resembled the synoptic physics of a winter storm and found the models sucked ass at those also. Several times a 1.25 qpf output for me at day 5 ended up south of me or so far north that I definitely would have gone from snow to rain had that been part of the equation. We just don’t remember those busts as much. Losing an inch of rain doesn’t hurt. Actually it means I got another day on the golf course, bike trails or hiking in.

Hmm if the trend continues the h5 will end up looking closer to the southern snow look. Maybe I’m wrong in expecting the surface to correct and it’s the h5 that will. That’s rare. Usually it’s the other way around.

Respectfully I didn’t mean to be ambiguous. First of all in this setup some criticism is warranted. The models were pretty bad across the board regardless of outcome on this event. But in general what I mean is this… we know we don’t have the ability to model the atmosphere completely correctly. We have not come close to completing that code. In some cases we know where we are lacking and write bias corrections into the math to try to compensate for our insufficient physics. So we have multiple model simulation tools like the euro gfs uk gem that all try their best to model the atmosphere. We have their ensembles where we run permutations to see a spread of likely errors. Then we use all of them together holistically to try to clean clues to what’s happening. No one of them is meant to be a rip and read forecast. If you look at each model run at long range only by itself they are next to useless. If you take all of it together and look for trends and clues factoring in all the model evidence together they are more useful (still not perfect) at being one piece of making a forecast. Even then they shouldn’t be the whole piece. Look at the crusade I’m on right now where the models are spitting out results that don’t align with my expectations based on the larger pattern drivers so I’m skeptical of their output. You should factor that stuff in also! Analog guidance and knowing your climo is part of the forecast puzzle as well.

It does but it’s unusual for a closed low that far northwest of that amplitude to produce a wave that escapes south of us. There is a feedback to this. With a closed upper level low they far NW the surface should amplify enough to feedback with some height rises in front. There is a reason there are no examples of a big SE VA snowstorm with this look. None. Zero zip. on the other hand reliable upper level data only goes back so far. Maybe it’s a once a century type thing and we’re about to see the first instance of it.

But don’t almost all our snows not show on guidance at some point also? Take Jan 6th. That storm was modeled as rain 7+ days out and ended up a 6” snow for DC. We just don’t treat those the same because it’s what we want. Also keep in mind most of the time a rug pull here ends up snow somewhere else. Your rug pull Jan 19 was a snow for me and PA. Our rug pull now might end up a snow for Norfolk! The models aren’t “taking out snow away” they are shifting the track of storms which moves the snow area. Sometimes that helps us. Sometimes it hurts us. But maybe because of human nature we focus on the times it hurts us more. There are plenty of times we aren’t in the snow zone 100 hours out and get snow. BTW I’m not being derogatory, I know there have been some posts like that, don’t lump me in I’m just trying to have a respectful dialogue.

Something to consider. You are comparing a forecast to a model output. The NHC forecast you’re citing uses evidence and model output is one piece of that. But you’re comparing two very different things here aren’t you? One is a tool to help us get a final product and the other is the final product.

Honestly they both look like we should be worried about a too far NW track not a coastal scraper. I’ve honestly never need so “confused” by model output. I rarely ever see something I’ve never seen before but this is if. A closed h5 low near Chicago and a h7 pass through PA = big snow to our southeast? Not in any book I’ve ever read.

I was in VA at my brothers. Got 8 there. Then went to visit my sister and by the time I got home the snow was blown all over. I went of a neighbors estimate.

In fairness 100 Hours didn’t used to be “close in” I made that mistake because several storms recently the euro did a great job from 120 on in and I falsely applied that to this

Right but those waves had a flat suppressive flow over the top and no amplified cut off h5 low to their west to pump some ridging in front. I saw why those didn’t gain latitude. I don’t understand this one. BTW I’m not saying this should be a HECS it doesn’t really fit that either. The best comps I saw that surface and h5 match are kinda messy storms (like as in sometimes multiple waves or miller b) not the perfect bombs but they weren’t suppressed south of us.

The NAM is doing what I envisioned. Focused more on the TN valley wave along the arctic boundary. Just wish it was showing on the better models too.

2” here

It’s a great match at the surface. But look how different it is at h5 and h7. Ignore the surface look at h5 and h7 the setup as the wave enters the TN valley 2010 now As the wave passes VA beach 2010 now