psuhoffman

There are some similarities but some differences with how this is being modeled by the non GFS guidance ATT. The 2000 system was all NS as there had been a weak southern wave that escaped off the southeast coast right in front that left the trough approaching cut off from any STJ influence. The upper low dove in slightly north of current projections and the initial primary rounded the base of the trough to our west and lifted all the way to Cleveland before the secondary coastal developed. The upper low then tracked across PA. The GFS upper levels look close to that storm which is why the outcome was somewhat similar but as of now other guidance not so much. And even the GFS has way more STJ interaction and the primary is coming across as far north. Just my 2 cents.

Mdecoy recorded a T

I love that site. No two storms are ever exactly the same but often those analogs can hint at if guidance is over or under estimating the potential of a setup.

So close He said “would be hard not to get at least one big storm in that look” Friends from Brazil sent their son to stay with us for his “summer” break the winter of 2002/3. He had never seen snow before in his life. At one point I remember he said “I didn’t know you lived at the North Pole. Ok I think we’ve killed him enough on that. He jumped the gun (guidance often jumps on a pattern change too fast then backs off) but pattern wise he wasn’t totally wrong. Just a week to fast.

He would be miserable. He loves the chase. You can’t chase something if it happens everyday.

@leesburg 04 y’all don’t understand @Ji. He is here for a specific purpose. He is all of our inner snow weenie souls unfiltered and unrestrained. We all feel it we just add a pinch of logic and perspective before commenting. He lets it out so we don’t have too!

That...and sometimes it’s the surface too. Lack of baroclinicity and or moisture. Two reasons seem to work in tandem. Models tend to error SLIGHTLY to to the south on the track of key features in the medium range. It’s not what it once was but it’s still an observable slight error more often then not. In the short range I’ve noticed nwp often underestimates the expanse of moisture transport on the NW fringe of comma head of a deep mature system. This accounts for a lot of that last second north trend with the northern edge of heavy snow. It also can be huge because somewhere near that NW cutoff is where you often get that convergence of best rates and lift. Often the deform sets up in that area where the best moisture transport from the CCB meets resistance from the confluence and the DCB creating enhanced instability and lift in an area getting very high ratios. Then it cuts off QUICK NE of that zone due to subsidence outside that band. So shifting this zone north 50 miles can take places out of predicted snow completely into a 20” snowstorm at the last minute with these intense east coast systems. Except Ji is comparing 2 week means last year to essentially a 4 day mean now. It’s not an amazing look but 2-3” spread over 4 days is a bigger signal then 2-3” over 15 days.

I would still rather see it slightly suppressed at this range. The old north trend isn’t what it used to be but systems do still find a way to eek north at the end more often then not. But it’s not like 20 years ago when we wanted to see it crushing Raleigh at this range. The typical north adjustment is much less then it once was.

BTW I agree with Wxusaf that we get better chances after this one.

You mean December 2001?

That’s what I was afraid of. The problem is the wave spacing and mid/upper upper level track was absolutely PERFECT for us last run! Problem was simply it wasn’t quite cold enough. That warm thermal profile allowed the surface low to track slightly inside of ideal for 95. Even that was perfect for us here. But we didn’t want “more confluence” and a more compressed flow. We simply needed it to be colder. We were barely into the heavy precip on the last run. It’s not like we wanted this to trend south. I know typically south and colder go together but in this case a south trend won’t work. That’s the right rope we’re walking. Imo what we needed was the same synoptic setup as 0z but with just a slightly colder thermal profile. 2 ways to get that. Either the guidance is simply too warm by a few degrees. That happens a lot. Or the system is slightly more amplified and thus better closed circulation to draw cold in. I was not looking for more confluence. Not sure how that would help us when we were already on the northern fringe of heavy precip! But...lot of time for more adjustments.

Yes...if that trend continues and we get a bit more space that wave can amplify. Normally more amplified isn’t good with a marginal airmass because it will often mean it pumps heights in front and further north solution. But in this setup if we also see a continued improvement wrt the 50/50 in front we could get both more amplified but still a south solution. That’s the combo we need. With such a crap airmass were walking a tightrope even though it’s a really good setup at h5.

That ridging is a bit Far East...remember we have 2 problems here. Temps but also suppression. We need the suppression given the marginal temps but that’s a pretty stout block:50/50 combo. Too much of a good thing and the wave gets squashed to our southeast.

We’re going to have to make this work with domestic cold for a while. We’ve done it before in blocking. But it does add a level of difficulty. ETA: the gfs has been REALLY struggling lately with not just synoptic but major longwave features. It’s had some runs of quality in the past but lately it’s been lost. Until I see signs it’s got it’s act together and can handle this pattern I’m giving it even less weight then normal. GFS has a lot less stratosphere resolution then the euro. I don’t know about the CMC. But the gfs was way off on the strat warm, delaying it by a week. I wonder if given what’s going on now that component is really hurting it.

@CAPE cmc illustrated what I mean by needing a clean transfer and tightly would (synced up closed mid level circulation). It has a perfect upper level and surface track to get at least some snow into the cities but it doesn’t really phase up well or quickly in the mid levels. It’s too diffuse. Add just a bit of amplitude though and that might work.

Icon has a totally different evolution then Euro. More GFS like. System for the 8th is all northern stream and runs to our north but then it has a wave right on its heels.

@frd the gefs did finally fold to the euro on the timing of the wind reversal. To be fair the Euro was originally a couple days too fast but the GFS was over a week too slow.

It looks like one of the more impressive events we’ve tracked and given the already pathetic state of the TPV it wouldn’t take much coupling at all to knock it out for the count this winter.

I doubt it can gain much (if any) latitude once to the east coast and with that h5 pass it’s possible. But the coastal plain needs 2 things to go well. 1. Get the storm to transfer to the coast quick and clean. 2. I say clean because once it does you need it to be a tightly wound system synced up at all levels (unlike the mid dec storm). Need the surface mid and upper levels to come together. No broad diffuse system that takes a while to redevelop off the coast. But if you get those 2 things with the current h5 look I could see a better result for the lowlands. But those are 2 big asks.

Looking better and better

One seasonal trend I’ve noticed is things tending to trend colder overall. I had snowcover for a week that looked like a torch from long range. That storm was a lakes cutter from 10 days out. Right now I was supposed to be torching and I had a snow sleet mix all day yesterday and awaiting freezing rain now. So far this is not a year where warmer automatically wins on guidance. We are lacking any true arctic air but at least we have that going for us.

Sometimes flukes happen but with a marginal airmass and that 8th system originating pretty far north to our west, I agree that would be a tough ask for the eastern shore.

6z EPS was considerably colder at the end of its run.

@CAPE will be happy to know the GEFS has a cluster of suppressed Richmond snowstorm solutions.

The pac trough has crashed in a couple times only to quickly pull back, despite at times guidance indicating it would be a more extended problem. That’s one reason I was never too concerned about the pac ruining things in the longer term.