eduggs

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.

3 or 4 really good hits out of 51. Several more fringe west and get ELI with decent hits. We need the OP to look close to threatening by 0z tomorrow.

There's time for sure, but not as much as there used to be. I actually think the OP inter-model mean has been really good this winter overall inside about 5 days.

I mean that they trend with the OP, not that they are perfectly clustered around it. The next few runs will be telling I think. If the GFS and Euro OPs shift west, then it's probably a serious threat. But if the ensembles continue to be west of the OP and the OP doesn't budge, that's a flag against the ensembles.

I think the GFS OP resolution matters. And I also think the GEFS tend to shift with the OP, rendering them relatively unpredictive of true spread and likely trend. The 18z GFS was pretty ugly. There's still time, but once this gets inside 5 days or so, you don't want to have to rely on massive model errors.

Remember when the GFS op was an extreme outlier with respect to every single GEFS member for run after run in the medium range?... last weekend... How'd that turn out? I have no confidence in the GEFS signaling the correct outcome or even which way to hedge. If the GFS and Euro don't start looking better at H5 by 0z, that should be a caution flag for sure.

I would urge caution with the GEFS. For last weekends inland runner, the GFS was consistently the extreme western outlier against every single GEFS member for run after run at this range. The GEFS failed to signal the correct outcome in this case. I think we need to see the GFS and the Euro make meaningful shifts towards an impactful storm to have any confidence. Right now they are not close.

I'm sure the hills will get at least a few hundredths of QPF. I meant no measurable on the GFS for the coastal plain.

The 18z GFS has literally no measurable precipitation for 2 weeks until it rains.

You find it hard to care about anyone outside of your backyard. We all know that by now. NY also borders three NE States. So the fortunes of people in eastern NY are similar to people in western NE.

Obviously. I was just pointing out that there might not be a lot of wiggle room outside of EMA in case this doesn't end up super tucked.

The 18z ICON is an improvement over 12z aloft. I looks like it would still mostly miss east, but the trof is better for us.

Those few tucked EPS members are pretty compact with the precip. field until the SLP is near the Cape. I'm not sure if places west of the NY border - NYC, POU, ALB - see warnings snows on any of those. Even the CMC was pretty limited on the western quadrant. If the low starts offshore, there is no initial overrunning until you get pretty far east or north.

Looking at 700mb, 850mb, and surface QPF... members 10 and 12 fringe us. 11 and 15 are misses.