eduggs

Great run on the 0z NAM. It's not quite what we want - still needs work - but it was the kind of run we needed to stay in the game. There's a good chance the 700mb low shifts north on future runs if that basic upper level evolution holds. That could end up looking very Euro-like. If everything else at 0z stays the same or shifts further east, this was probably a blip run and we're probably toast. It would be huge to see meaningful shifts west from the rest of 0z.

Huge 0z tonight. If we get movement back west we're still in the game. If not, time is probably running out outside of eastern LI. The EC works as is, but barely. We need model support.

It's a very minor shift west. And the improvement is partially offset by a slightly shallower mean trof and worse upstream height field orientation.

The NYC area got one decent event for those lucky enough to have been awake to witness it. Some areas have seen no events of significance.

Suffolk County LI is still a decent spot, but NYC west is in trouble... approaching longshot territory.

It looks like we're pretty much cooked except maybe parts of LI. Bummer that guidance universally trended away from us. We're getting to the point where we would need major models errors just as we approach the short term when those errors become unlikely. Late phase and offshore low was the clear risk with a super fragile trof setup. Obviously with such a sensitive setup, this could always come roaring back. I was hoping we would at least stay within striking distance today so small shifts west would get it done. But now unfortunately we need pretty big shifts. The season of tracking frustration continues...

The UK is far enough east that it almost fringes Boston. Not quite though. H5 still looked salvageable for us. No precipitation west of NYC. Totally plausible... just to keep us from getting greedy with high expectations. From here we need to avoid any major shifts or seeing multiple runs in a row shift east.

I don't think it matters too much whether the EC shifts one way or the other tonight as long as the changes are relatively minor. I'd guess a shift east is slightly more likely than west just based on it being on the western edge of consensus, but who knows. Either way, the outcome won't be decided tonight. All of the 0z runs are close enough where modest changes could lead to a widespread major snowstorm.

Overall all global - EC, GFS, CMC, UK, and even JMA and ICON have been pretty consistent for the past few cycles... especially considering the range. There have not been wild changes and there's even a general inter-model consensus on trof amplitude and orientation as well as location and strength of surface features. Minor differences obviously have huge implications for surface weather, but this consistency is a marked improvement from years past.

CMC looks like a big hit NYC east. Plenty close enough for big potential everywhere.

Not surprised about the 0z GFS. Certainly worse, but not that far off. Doesn't change the outlook at all.

So far at 0z - NAM, ICON, RGEM - all support a good shot at a major snowstorm. Eastern sections would seem to be favored considering the late developing trof, but there's good banding potential and if we're lucky, at least a moderate duration of snowfall.

The 0z RGEM has a slightly flatter and further east trof compared to 18z. As is still a pretty potent threat. And we can live with run to run changes like this.

The NAM provides slightly more weight to the high impact potential. In an ideal world, it's probably a day or so too early for such a perfect looking run, but I guess it's better than a lousy run. Obviously this could still fail a few different ways - OTS or even a too-wrapped up early occlusion over Delmarva. But I suppose it could surprise on the positive side too - maybe Friday will end up relatively snowy?

We're all just pretty much guessing. If the GFS eventually shifts westward I expect it to shift slowly. It has exhibited relatively high run to run consistency at this range recently, even when it was an outlier. If I had to guess the eventual outcome I'd say offshore track east of the 18z Euro but with a mature upper level circulation and expansive northwestern precipitation shield (i.e. trof pretty far east but wrapped up). Good hit for LI, parts of CT, and maybe coastal NJ with NYC right on the edge of good snow. In other words I expect a late phase but an explosive tilting and deepening of the trof thereafter. Just a wild guess though.

60-70mb surface pressure difference possible with this. That's solid.

That's a sick look for coastal NJ to LI on the EPS. The QPF mean doesn't even capture the magnitude of impact. Probably half of those members are true blizzards for coastal regions.

If the trof doesn't collapse and let this slide east, I don't think we've seen the upper echelon of modeled QPF potential with this. I definitely would not forecast an historic event at this point due to high failure potential, but I could see a few huge QPF bomb runs over the next few days.

Seeing relatively small run to run changes would be a really good thing at this stage. We don't want big shifts in either direction. Best case scenario this very slowly edges westward over the next three days.

Most of us are in a great spot at this point IMO. If the status quo holds, its a significant storm for NYC east. If it shifts slightly west, it's a major snowstorm for everyone. I'm curious if the frontal snow on Friday holds up, notably depicted by the 18z NAM. That could add significant duration to the total event. I suspect it trends lighter and probably later in the day Friday/Friday night, but it's something I'll be watching. It would be great to extend the snow to parts of 2 days. This could still easily fall completely apart. The trof still looks really fragile despite encouraging trends. But the likelihood times impact potential is easily significant enough to be very excited.

Ordinarily that location works for us. But not if the SLP takes an offshore track like the UK. Then it's a whiff... an impressive windy whiff.

Well it would be nice to quickly reverse the trend. But wobbles often come in clusters of successive runs. I wouldn't be shocked if the GFS is similar or worse this run. But we can still recover from this point. By tomorrow and especially Wednesday it will be increasingly difficult to recover if the consensus is OTS.

OTS IS STILL a big concern. I've loved the trends today prior to 18z. But the trof evolution is fraught with fail potential. If that shortwave moving through the SW doesn't round the bend, this misses east or is low impact. We've had no luck with timing issues this year. If the shortwave rounds too quickly, this probably bombs too early and we get mix or rain. But at this point that seems to be the lesser likelihood.

A couple blizzard runs around 60 hours out followed by a complete whiff is worse than zero IMO.

Which makes the floor lower than the sub basement.