psuhoffman

It's their fault, we should get them

I think maybe the reason I didn't see any 10" plus snows to hit the Delmarva or Richmond with this pattern...but then I pulled up Elizabeth City and VA Beach storms and the first one I picked in Feb 1980 was a decent match to this pattern... is perhaps if there is a southern wave that stays detached and doesn't phase with a TPV lobe in the upper midwest it will be suppressed but it will slide even further south then guidance was when it was showing us on the NW edge of heavy snow and crushing the Delmarva and southern NJ. Any storm that develops with a TPV there probalby has to have some interaction and come further north because if it phases at all its gonna pull it pretty far north in that flow....OR with no interaction its going to get squashed really far south because of the TPV sitting right there...there is no in between options typically. Because all guidance was showing a hit or a close miss SE when I started this I was not even considering "what if it ends up squashed all the way down to NC" lol

But again...look at the H5 on that storm...easy to see why that got suppressed and why it was a big SE of us snowstorm.

I was in NJ just southeast of Philly. Went to bed the night before expecting a foot of snow. Snowing by morning on every forecast. Woke up and could tell the sun was out from the light through my window shades and heard the wind howling out of the west and just know it was over. Crazy gradient, ACY got close to 20" and nothing for me 15 miles SE of Philly. We did get some flurries later that day on the fringe as it passed by.

The comeback starts tonight

no not to that extent. And March 01 isn't a great example anymore, and didn't happen for the same reasons this would come north. Actually it was a much more suppressive setup, also had a crazy block but centered more east and a TPV over Quebec right on top of us...but it had a strong SW rotating around to the west split and drop and models thought that would bomb. And it might have but one part of that mess was there was no cold. The airmass sucked. 850s were to our north. We were relying on dynamic cooling and a coastal pulling down cold air. Had we had the airmass we will have this week we still would have got a 4-8" snow across our area actually. But that wave didn't bomb and eventually it phased in with the actual TPV up over New England and then it bombed which made more sense given the suppressive flow down in the mid atlantic and the lack of a baroclinic boundary to activate the wave initially. I respect all of these points, and yes this is WHY the models are saying what they are...BUT...again back to what I said yesterday, why can't I find a single example even close to this setup that caused a big snowstorm for southeast VA and the Delmarva? I looked at every one I could find and none had a h5 close to this. But Bob you brought up something in your second post just now I had not considered enough...that this is just an extremely anomalous setup and so we haven't ever seen it before in the short time we have upper level data available because we've not had this anomalous a setup enough times for to occur, NOT because this isn't a likely outcome in this setup. Still...there are some examples of a TPV getting stuck under a block and breaking a lobe off into the US. And all the ones I found where it tracked where this one was did one of 3 things...a weaker flat wave slid under and there was no significant snow anywhere...a snowstorm further north... or a 3rd option I had not considered yesterday but with todays further south trends came to me...and some digging confirmed it...I wasn't even looking at VA beach and eastern NC snowstorms...and so I thought...this might be heading that way take a look...and the first one I pulled up, one of eastern NCs biggest snows, and damnit its a really close match to this pattern with a closed TPV lobe over Ohio. There definitely is still more of a H5 extension around that TPV passing south, so it still makes more sense, but its close enough to make me consider...maybe this is heading to a VA beach to NC outter banks snowstorm!

Look how far back the light precip gets. That’s because the trough is way way way back to the west. So why is the storm racing off when the energy is back in the Ohio valley.

Honestly…If all the globals looked like the NAM right now I’d be sweating bullets that it could trend further NW given a closed H5 and h7 low tracking through Ohio and PA. Honestly that’s normally a snow to mix type track for us. For reference March 2017 Dec 2020 and Feb 2021 had similar mid and upper level tracks. If I was looking the h5 of a long range run like I often do first when I flipped to the surface I’d kinda expect to see a central PA snow jack type storm. The extremely cold air mass and 1050 high helps mitigate that here. But remember when someone was throwing out March 2001 because of the h5 similarities. That was modeled to miss us south all week and Mets were saying what I am now, that it “should” be more north. Then at 48 hours it came north…and just kept going lol. Now wouldn’t that be the ultimate kick in the nuts. If tomorrow all the models come back north and show us getting 20” and we throw a party. Then they keep going and it ends up a central PA jack and we get snow to rain!

Honestly that’s a noise level difference for 84 hours. And people screaming about the kicker it’s worse on the nam.

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.