psuhoffman

Ah new peramiterization same flawed math. I kid of course. If not for the euro the gfs would be the gold standard.

No but in January with a colder airmass and less scolding water temps the low likely doesn’t track as far west.

I’m not doubting it but I thought they changed the core when they upgraded to the FV3 version. Being non hydrostatic v the old GFS you would think the physics have to be different. Yet it has some of the same weaknesses from what I’ve see so far. Makes me wonder if there is something in the methodology or data assimilation of NCEP behind it.

It’s the only guidance that shows me all snow. But that’s simply because it can’t pick up on mid level warm layers. Never has. Although I guess this is the new GFS lol. But I find it suspect that EVERY other nwp is wrong on that warm layer.

If only I could believe the GFS lol

Only good thing about sleet is it makes the snow harder to melt. If we had a nice snowcover I wouldn’t mind a sleet storm to cover and protect it.

Definitely not a heavy snow sounding. Maybe that’s after that band moves through is the subsidence.

if we could get the NAM track with the euro thermals we would be good lol

Ugh that’s kinda a nightmare for my area

We’ve had snow events work with less. You’re 100% that the look up top isn’t the stone cold killer perfect analog look. But it’s a good enough look to make a snowstorm realistic but we would need some help. The perfect look up top makes it where more factors can go wrong and still work. This setup we needed more to go our way. Not enough did. Even with the 50/50 vacating had that rogue SW not dug the trough west of us we probably got a decent snow event. But a few things went wrong and it’s Dec and the block wasn’t perfect enough to offset. But I would take this look all winter and roll the dice! Might not get a hecs but we would probably get a couple warning events with enough chances with a similar pattern imo.

Agree. The spacing was just a little off. Even with the SW that dug the trough that was pointed out had that 50/50 been a little slower to vacate, but a huge gap opened up and this storm is taking advantage of the ridge to cut inside. It happens. It’s December. But I’ll say this...and I’ve been too busy to track this and post in long range so I took a break but the -AO NAO does not look like a transient think. I think we finally are getting our winter where blocking will be a significant feature. If we get a -AO winter and the pac isn’t a disaster (so far it’s meh but not awful) and still manage some awful single digit snowfall then the “somethings” wrong argument has more legitimacy. Blocking won’t guarantee we get great results but it should (absent a dumpster fire Pac) get us some snow events. If it doesn’t it’s gonna get ugly in here.

At least I’m not worried about ground temps. I still have snowcover.

If that track verifies I guarantee you Philly doesn’t get that much. Maybe a few inches. NYC won’t get prolific #s but their saved a reasonable storm because it does eventually hit the brick wall and turn due east. There is a block. But it exerted its influence ~100 miles too late for DC to get a big snow. CAPE pointed out, and was right, that the block is centered a little north of ideal for us. Still it was good enough to work if other things went right. We don’t need PERFECT. But the trough digs too far west and pumps ridging ahead of it and the 50/50 is just a little too far NE to prevent it. NYC is far enough north that it barely saves them. At least to an extent. The big totals will be in central PA and North of them.

Usually around 500mb or a little under that.

Ok I think some are over analyzing a run where the low tracks OVER BALTIMORE!!!! Hopefully it’s wrong. But come on. If the low actually tracks from Richmond to Baltimore to Wilmington anyone from 81 east and south of York PA is screwed. We know that. This isn’t that complicated. Just hope that track is wrong. If you get the 12k NAM or GFS track with the euro storm presentation we get a big storm 95 NW. unfortunately the best guidance at this range we have looks like poo. No one mentioned both the RGEM and HRDRPS look awful and had their worst runs at 18z. I am rooting for the gfs but...it’s the GFS lol. Other then the GFS and 12k NAM everything else I saw continued to degrade at 18z.

Because the surface isn’t all that affected and that map counts anything where any layer is somewhat close to freezing as snow. They are awful.

It’s a torch at mid levels which is expected when a low tracks over Baltimore!!!! Those maps are lol. They have be at 16” but when I check the temps at all levels I can only find about .4 qpf that’s snow even up here.

Ugh so much for a good trend 18z. Worst euro run we’ve had by far.

Unfortunately snow growth (crystallization) can only happen in the DGZ and once it melts under there the rain can only freeze into sleet. That deep of a cold layer just guarantees sleet v freezing rain.

The mid levels have a very March 17 look on the 3k NAM

@mappy

warm layer at 750 mb

Yes...track might have been slightly better but it continued the trend of tightening up the mid levels so there is a much tighter thermal gradient NW of the low track. Verbatim you go to sleet for about an hour in the afternoon...then back to snow for several more hours before you lose the thermals right as the best precip is moving out anyways...you might get a little light snow on the back end but that looks mostly northeats of you. But this is a pretty good run...80% of the qpf is probably snow. The warm layer never makes it further west then that ridge you can probably see from your house just west of leesburg. Adjust 10 miles east and you stay all snow. Actually...if you take the euro and adjust it to this track we would both get a pretty darn good outcome. Even closer to the cities would do well. That is probably what we need here...slight eastward track adjustment and this new idea of a better closed circulation to be correct.

It is...we got the trend we need for a late save...no more further westward adjustment to the track...and a continuation of the better mid level close/pass to promote a tightly wound system by cutting off the easterlies sooner. A more tightly wound synced up "phased" system at all levels will cut off the easterlies to the west of the low center and prevent that warm layer from blasting as far inland... But like i said we need the west trend of the track to stop for that to matter...if we can keep the track east of us AND get that trend to continue we could save a decent outcome here. Maybe no Ji level win but something most of us would take right now.

Well...I think the inside track is becoming pretty locked in. But there have been some developments with a better H85 and H7 pass that are causing a more tightly wound thermal gradient with this storm and could also make the possibility of some banding as the low departs real. If we were to get the west trend of the low to stop and perhaps adjust just a slight bit back east...but keep those factors...some places could still do well. It's possible. But one warning...the west trend of the low track continued with 12z guidance. And the mitigating factors I listed above are maxed out. For example..on the euro there is a time about 3z when the low is literally on the east side of Baltimore and yet its snowing here. A couple hours later that snow rotates through the north side of Baltimore with the low over NE MD. But if that track adjusts any further west...well nothing else is going to matter...you aren't going to get snow if you are UNDER the low or east of it. So we need both the better mid level depiction of the 12z guidance...but also we absolutely NEED the west trend of the low track to stop NOW. Get a slight east bump in final track, which is very possible...trends don't always continue right to the end...at some point guidance could pick up on reality...and maybe even over amplify some. Get that east adjustment by 50 miles and keep the better mid level look and maybe places closer to the city still reach warning criteria. Southeast of DC yes...this just isnt the right setup and I don't see anything that saves them. For 95...its getting tough but there is still an outside chance if those things I said above break right...namely we get a slight east adjustment to the track AND the better mid levels. For people NW of the fall line...very much still in the game for a decent event so long as expectations have be reset. Those crazy numbers we were throwing around 48 hours ago are gone. The track is just too far west for that...but we could still pull out a decent event if things break our way. But like I said above...its troubling that we continue to see a west shift every run on the guidance and we are completely out of any breathing room now. IF there is any further west adjustment then its a fail for everyone east of the blue ridge and south of PA.