jwilson

'94 I was in Philly, so I don't remember a storm of any significance then. 2020 was technically double-digits, as you all pointed out. I forgot and double-checked my notes, and we hit 10.5" locally. True that qualifies, it was kind of a freak thing and quite localized because of the CCB. 2018 I was in Morgantown and I didn't get anywhere near what Pittsburgh did for that event? I don't even remember it at all. Biggest storm I had that winter was 3" locally. Let me add: those others storms I mentioned were all closer to two feet than simply double-digits, so I think my bar is probably a little higher than normal!

Haven't seen a double-digit synoptic event since 2016. I'm guessing next year it continues if we have another La Nina, which makes 10 years and probably the longest I've gone in my life without such an event. Growing up, I remember 1993, 1996, and 2003 most notably. Since then was 2009-10 and 2016. I'm starting to itch like an addict, lol.

Everyone can take a week off. Going to be quiet for a little. If another -EPO develops like the ensembles are showing, we're going to get more cold air in early March. Question is if anything becomes of that, but I think that regime prefers the cold & dry formulation we've seen already this winter. I'm still chasing a big storm. Little nuisance snows at this time of the year aren't of interest. They're fine in November and December when setting the holiday mood.

Yep, 9th-10th storm from that year. Third snow in a week. I was going through some old photos and found a bunch from that week, including some other analysis, etc. Here's your visibility progression for reference: Bottom picture is from the height of the storm. Same street, obviously, and you can see how low the visibility was during the heaviest snow. Middle pic is actually from the storm on the 6th, but I used it because it was more "normal" snow and the same general angle.

Missing those days...

Models have intermittently teased a warm up, but with the 12Z suite, I'm not seeing anything extensive. GFS is most aggressive at the very end of its run in early March, but that's only three days or so. Seasonal trend has definitely been staggered and brief warmups followed by more seasonal cold. I guess if that continues, we wait on spring and have snow chances on occasion.

I would think this winter failed because, in the beginning, it was primarily driven by a fairly significant -EPO phase. I don't think that's the best way to score a more typical east coast nor'easter, largely due to the position of the western ridge axis. It resulted in a numerical +PNA, which is exactly what we want, but I don't think that's the same as a +PNA that's driven more "organically," or at least coupled with an EPO that's more nuanced. The other problem was all high latitude blocking was transient. Any time the NAO or AO spiked negative, it would immediately retreat back into a positive phase. Basically, everything was relying on perfect timing to produce. Much of what was forcing storms under the Mason-Dixon wasn't primarily related to this blocking, either. It was a matter of the cold source TPV getting dumped into the CONUS with regularity because of the intense pacific flow. As others have mentioned, the speed of the pacific flow is what often gums up the works. It also seems to be reducing modeling accuracy, but that's my own speculative deduction (an educated guess). We can get these little events and cold under this regime, but like most Ninas, in general, you're talking about more cold and dry than cold and snow.

So when is the next warm-ENSO winter? lol

Predictably, the mid-week storm is turning into another southern slider and missing PA. That's the seasonal norm. It was all too delicate and tenuous of a setup. Too many things to go wrong. It's a shame all the models at once locked onto a big solution because it's a massive tease, but I think that's the danger of model watching outside of a couple days lead. Also further demonstrates the tendencies of a cold-ENSO winter, and why the events in warm-ENSO winters are much more "stable" and easier to track. This isn't even 1996 anymore, and the increased speed of the northern jet is difficult to navigate.

That backside low getting close to Seattle isn't at all what you want. We'd prefer it closer to the Gulf of Alaska. I guess the models have trouble with the speed of the northern jet in the long-term. You wonder if that sort of east coast amplification is even possible in this pattern. Shows how perfect the timing would have to be.

Agree, that's definitely been the trend. We've seen a number of big storm looks around 180 hours and then they gradually taper to a messier, progressive wave. It's why areas south of the Mason Dixon keep winning. Nothing along the coast can amplify in this pattern. We see it here again as the Gulf of Alaska low is starting to close the distance between it and the TPV lobe. That wrecks the ridge spike in the west and doesn't allow the lobe to ride down the backside of the trough and phase. If that backside low keeps getting closer, you'll get another weaker s/w that spits sideways off the coast. D.C. might still get something, but areas from PHL north are toasted again. Models keep underestimating the speed of the northern jet in the long-term. Even the ensembles have looked great around that week mark and have been way off on snow totals.

I believe there's a very high correlation between a deep -AO spike relax and a significant nor'easter. Something like 90%? I can't remember off the top of my head, but we just peaked at about -5 on the Arctic Oscillation and will immediately shoot back in the other direction. That sort of quick-change is volatile. It lends credence to the idea of a major storm occurring soon, but the details are TBD. The one big problem is this not being a Nino, we don't have the typical Miller A southern juice. We can "fake" that in a way with a big phased element, but I think the overall setup is more tenuous than if this were a typical warm-ENSO pattern with overrunning. January 1996 was one of those extreme outliers, and we haven't seen that again in the 30 years since, so you know how rare it is. If you get that Gulf of Alaska low to spike that west coast ridge more, or sag the TPV lobe quicker, oriented more north-south, you could trigger an earlier phase that pulls in a more western component to the storm or start developing a wider precip shield. I think that's how Pittsburgh wins from this, but it is more difficult in this overarching pattern, and even 1996 - as the most extreme case - is barely a Top-10 snow for PIT. Granted, there's no history of anything until it happens.

The outlier 0Z Canadian was surprisingly close to an all-snow event for Pittsburgh. Took the surface low on a line from about Charleston to Martinsburg. GFS cuts straight up to Weirton. Euro brings it to Allegheny County. Latter two drive into the finger lakes. I think it remains quite a long shot to see a moderate snowfall from the weekend event. Front-end snow is uncertain, but I think the ceiling for that is probably 2" tops, and that's from the most aggressive GFS. The Euro is about 1" total. That's largely where my expectations lie. The reason for the difference in the CMC vs. Euro/GFS camp is the lag in the TPV on the latter two. The former moves the TPV eastward much quicker, placing it almost due north of the system. That means the system has more trouble cutting west. We are going to need that confluence to speed up, because the southeast ridge is pumping the heights ahead of the system and setting the boundary basically right over us or even to our north. If we don't get that timing right, it's a full-on rain storm. Maybe we can find a way to get lucky, but there's not much support for it in the modeling as of now.

I think the suppressed repeat is the most likely outcome for that storm as the blocking is peaking. Hopefully not for obvious reasons, but it would seem the winter of southern MD / north central VA continues for now.

Just for fun, this showed up on the long-term GFS Ensembles: Anyone have a guess as to what that looks like? I'll give you a "hint" -