NYC/PHL December 24-27 Potential - Part 2

[forkyfork]

the other one was getting too cumbersome

brief summary: euro very amplified and probably overdone, gfs is way suppressed and probably too powerful with the polar jet, the ggem is a good compromise, and the ukmet has gotten better, but is still OTS

[Kaner587]

In all honesty I wouldn't go as far as to say throw the GFS out because I don't have enough met. knowledge to suggest such a move, however, it literally has zero major model support, with the ukie seeming to support an OTS scenario but it still has a MAJOR phase getting the surface low down sub 970 so the two solutions share a relatively similar track but they diverge form there. Just some food for thought because if the GFS is right it literally will have performed better than every other major model, which is not something it is accustomed to doing, if it has a solution that is different than most model support, it usually has at least one major model on its side, this time there is nothing. DGEX/Nogaps support it but no one would consider those "major" models

[Sn0waddict]

The GFS Ensembles have consistently been OTS if I recall. It will be interesting to see if they yet again.

[BL03]

in a normal winter (not heavy -mod la nina/nino) I wouldn't be worried so much about the speed of the southern s/w with the models but this year it has already caused havoc with forecasting. Normally GFS is too surpressed/se with major storms and the euro nails things. Even though the last several runs of the euro have been great we should all still be in extreme caution mode. Hopefully the euro is not slowing the s/w down too much but no one knows this right now. The ridging could be the one piece missing from our last OTS storm that does it this time..

bring on 00z!

[Zir0b]

In all honesty I wouldn't go as far as to say throw the GFS out because I don't have enough met. knowledge to suggest such a move, however, it literally has zero major model support, with the ukie seeming to support an OTS scenario but it still has a MAJOR phase getting the surface low down sub 970 so the two solutions share a relatively similar track but they diverge form there. Just some food for thought because if the GFS is right it literally will have performed better than every other major model, which is not something it is accustomed to doing, if it has a solution that is different than most model support, it usually has at least one major model on its side, this time there is nothing. DGEX/Nogaps support it but no one would consider those "major" models

GGEM ensembles are way out to sea...not even close to operational run

[Kaner587]

GGEM ensembles are way out to sea...not even close to operational run

Thats true I didn't think about ensemble support, still the EURO has ensemble support.

[tmagan]

In all honesty I wouldn't go as far as to say throw the GFS out because I don't have enough met. knowledge to suggest such a move, however, it literally has zero major model support, with the ukie seeming to support an OTS scenario but it still has a MAJOR phase getting the surface low down sub 970 so the two solutions share a relatively similar track but they diverge form there. Just some food for thought because if the GFS is right it literally will have performed better than every other major model, which is not something it is accustomed to doing, if it has a solution that is different than most model support, it usually has at least one major model on its side, this time there is nothing. DGEX/Nogaps support it but no one would consider those "major" models

The GFS does have major model support, whether it is right is another story. My inkling is it might be on to something.

[NortheastPAWx]

The GFS does have major model support, whether it is right is another story. My inkling is it might be on to something.

Where? DGEX? NOGAPS?

Not convincing.

[GD0815]

It seems that both OTS and a coastal are on the table....it looks to me about 50/50 now, although certainly you can make a case for a compromise with the coast getting the brunt and light to moderate snow making it to the I95 corridor. In fact that is probably the safe forecast right now. I feel like half the models are leaning one way, and half the other, and that doesnt even count ensembles, which seem to inspire a little less confidence that this will happen. I found it weird that the 12z GFS didnt have a coastal bomb as a solution of any of its members, that gave me pause. Then again, we all know the GFS has a tendency to do this 4-5 days out It should be an interesting one to follow, and I hope for several radio shows---I think the jinx argument is silly, the fact is east coast snowstorms are hard to get, and the odds are always somewhat against it. I learn so much from the radio shows, and they are fun to boot.

[eduggs]

In all honesty I wouldn't go as far as to say throw the GFS out because I don't have enough met. knowledge to suggest such a move, however, it literally has zero major model support, with the ukie seeming to support an OTS scenario but it still has a MAJOR phase getting the surface low down sub 970 so the two solutions share a relatively similar track but they diverge form there. Just some food for thought because if the GFS is right it literally will have performed better than every other major model, which is not something it is accustomed to doing, if it has a solution that is different than most model support, it usually has at least one major model on its side, this time there is nothing. DGEX/Nogaps support it but no one would consider those "major" models

Multi-day guidance appears to be trending toward a higher amplitude trof than the GFS has been showing. Another gradual trend has been to decrease heights across and off the east coast days 2-4. This suggests that the surface low is likely to be forced south toward the Gulf coast and eventually the Florida Panhandle.

From there, with a deep and increasingly negatively tilted trof and PVA on the eastern flank, a rapidly deepening SLP is likely. But an evolution as perfect as the ECMWF, which is also the slowest, seems least likely. An offshore compromise between the GGEM and UKMET probably has the highest statistical likelihood. This would follow the baroclinic zone, is consistent with seasonal trends, and is reasonably close to multi-day ensemble means. Impact would be greatest along mid-Atlantic coastal sections and possibly far eastern NE.

[tmagan]

Where? DGEX? NOGAPS?

Not convincing.

KMA, JMA (to a degree)

[Sn0waddict]

Where? DGEX? NOGAPS?

Not convincing.

GGEM ensemble mean are wayyy different than the OP. Ukie is also sort of OTS.

Should be an interesting night to say the least.

[NortheastPAWx]

KMA, JMA (to a degree)

So? Again, not convincing.

[tmagan]

So? Again, not convincing.

So I guess it only counts if it shows a blizzard?

[GD0815]

KMA, JMA (to a degree)

i actually think the JMA is a good compromise solution, we'll see...

[SnowGoose69]

GGEM ensemble mean are wayyy different than the OP. Ukie is also sort of OTS.

Should be an interesting night to say the least.

The UKMET has been so bad on the last two storms I haven't even looked at one run of it, the GEM ensemble mean is the one thing I don't like right now, as well as the 18Z NAM at 500mb looking a bit more like the 12Z GFS from 72-84 hours.

[winterwx21]

We basically have no clue what's gonna happen. Knowing how difficult a La Nina pattern is and knowing how inconsistent the models are, we won't have a good idea until late week. I really think that's all you can say at this point.

[SnoSki14]

I'm not sold at all on this event. It's another one of those all or nothing events where we get the phase and get a MECS or we're slightly off and we get nothing. As we all know, it's extremely difficult in a strong Nina to get a full phase and bring the storm from Florida up to the eastern seaboard. Right now I'm thinking a solution in between the extreme Euro to the lackluster gfs which would put us in a light to moderate event (3-6").

Also if the models slow down the event (not a good sign), it could be one of those delayed storms that never materializes. This is similar to the arctic air masses shown to impact us in the longer ranges but they keep getting held back or they never arrive at all, and if they do, they are significantly moderated.

Somebody convince me that the Euro is possible, show me some analogs that could fit with this storm because I'm not buying it.

[NortheastPAWx]

So I guess it only counts if it shows a blizzard?

Your "support" comes from non-major models. Your best shot is the GGEM ENS. The UK is sort of in the middle of things. I doubt the 967 it has would go OTS from what I read.

[eduggs]

Where? DGEX? NOGAPS?

Not convincing.

Taking into account most of the mid-range models and the available ensemble members, over the past few days there have been more offshore tracks than coastal tracks. And only a very few just onshore tracks.

[Maximum lawman]

in a normal winter (not heavy -mod la nina/nino) I wouldn't be worried so much about the speed of the southern s/w with the models but this year it has already caused havoc with forecasting. Normally GFS is too surpressed/se with major storms and the euro nails things. Even though the last several runs of the euro have been great we should all still be in extreme caution mode. Hopefully the euro is not slowing the s/w down too much but no one knows this right now. The ridging could be the one piece missing from our last OTS storm that does it this time..

bring on 00z!

So this is an interesting post. Normally in la nina years, systems race across the country - that argues for the GFS solution. If the GFS does not start moving toward int he Euro in the nwxt couple of runs, it's probably on to something.

I do want to note a complemenary idea - this season when there's been a major coastal, the GFS has had the right solution in the 144-180 time frame (at least in terms of QPF) and than lost it before slowly trending back toward the original solution. I should note that in these set-ups the GFS has been horrid in the 96-144 farme, and only good within 48 hours.

So the bottom line is this. If the Euro starts speeding up soon, that would speak volumes about a solution. If it doesn't, don't expect the GFS to get on board until Thursday or even Friday...

[eduggs]

Your "support" comes from non-major models. Your best shot is the GGEM ENS. The UK is sort of in the middle of things. I doubt the 967 it has would go OTS from what I read.

Right now all we have going for us is the Euro, Euro ensembles, and a late developing GGEM.

[Snowtrain]

I am basing this off of an unsure thought, maybe someone could comment on this for clarification? If I remember correctly, last week when some of the models were showing a potential for cyclonic development near the coast wasn't the S/W as it ejected form the West coast underdone on the models, specifically the GFS? If my memory serves me the NAM actually fared rather well on that storm and portrayed the S/W as much more energetic than the others. Furthermore, the NAM has seemed to better forecast the evolution of the low in the Northern Atlantic and the snow that has been effecting Northern New England for the last 24 hours or so as a result of the low retrograding southwest. Basically am I remembering this accurately and did the NAM in fact handle the S/W better as well as the overall forecast last week than the GFS? If so I feel more comfortable in believing that it is doing the same with this S/W as it ejects out of the Rockies. It is depicted as a much more energetic wave on the NAM,EURO/CMC than the GFS as it is leaving the Rockies and heading towards the TX OK border and seems to lend support to the EURO camp if it were to be extrapolated outward. Thank You in advance!

[NortheastPAWx]

Right now all we have going for us is the Euro, Euro ensembles, and a late developing GGEM.

I think the analysts were saying the NAM, extrapolated, would bring on a good solution. I'll take the GGEM/EURO and ENS/NAM over the GFS/DGEX/NOGAPS/KMA every day.

[Sn0waddict]

I think the analysts were saying the NAM, extrapolated, would bring on a good solution. I'll take the GGEM/EURO and ENS/NAM over the GFS/DGEX/NOGAPS/KMA every day.

I think people are point more towards the trend. This time yesterday the GFS, DGEX, and KMA all showed solid hits.

It seems like a lot of people prefer quantity over quality. Many would probably feel safer with all but one model showing a hit, even if it was a dependable model showing a miss.

[eduggs]

I think the analysts were saying the NAM, extrapolated, would bring on a good solution.

It looked moderately encouraging to me at the end of its run, but not highly threatening. And the 18z DGEX, which is one method of extrapolating the NAM, essentially misses us. I do not think you can conclusively use the NAM to support any conclusion at this juncture.

[Kaner587]

tmagan I'm a little surprised you used JMA and KMA to make a point, and then went as far as to call them major models. As far as I'm concerned, and I'm assuming most mets feel the same way, major models =GFS/ECMWF/UKMET/GGEM and to a degree the NAM when it gets to the shorter term or the middle of its range. That doesn't mean we should discount an OTS possibility, it is to say though that ANY DAY I'd take GGEM/ECM/UK over any other countries models. Btw KMA was awful with the last storm as well

[atownwxwatcher]

Right now all we have going for us is the Euro, Euro ensembles, and a late developing GGEM.

Not that I am comparing this to 1996 but was not the ECM the only model that locked on to its solution of an east coast blizzard at 7 days out and never wavered? I seem to recall that & the media downplaying it and calling for flurries the night before even because the GFS was the last to the bandwagon of the ECM...

[atownwxwatcher]

It looked moderately encouraging to me at the end of its run, but not highly threatening. And the 18z DGEX, which is one method of extrapolating the NAM, essentially misses us. I do not think you can conclusively use the NAM to support any conclusion at this juncture.

I believe the DGEX uses the GFS to some extent for its solutions so it would not be too surprising that it is OTS...

[Sn0waddict]

Correct me if I am wrong, but isn't there an 18z UKMET?