Powerful Multi-regional/ multi-faceted east coastal storm now above medium confidence: Jan 29 -30th, MA to NE, with snow and mix combining high wind, and tides. Unusual early confidence ...

[PhineasC]

Precip looks more like GFS now, so things seem to have come into line. NAM confines the really noteworthy snows to a stripe of E MA and the Cape.

6-10

 

[Typhoon Tip]

Once again ..I'm a few pages back this morning... so this may be redundant, just my take: 

The GFS solutions have never consolidated this system very well. Despite late attempts to finally conceded to a better centered structure/west,  beginning perhaps 18z yesterday, the 06z seemed to get stuck to me.  It appears to be 'stretching' the system apart as an insistent model cycle after cycle result, and it is effecting it's maxing - example, those multi- nodal cyclonic pearls out there ( which appear dubious to me).  Thus, subtracting from the total.  It's got a anchor-point low situated back where ( in principle at least ...) the NAM and Euro have their "main" low at 30 hours, but it has perhaps 2 nodes rippling out NE and accelerating away ... one SSE of ACK, and another more discerned due east of Cape Cod at that particular frame.  That shearing/smearing NE out there is related to why heavier QPF/ .. placement thereof, can't get farther west.  I can't see where to correct that , because it seems like the model is constructing a 700 and 500 mb surfaces to allow that to happen.

Contrasting, the NAM and Euro don't do that, as much.. The Euro does some aloft 500 mb weirness, but the NAM is strangely nucleated at 500 mb. Hmm..but, with these mid level attributes, they appear to in turn maintain more consolidate/west lower tropospheric response(s). 

It seems the convective sequencing and how those can feed back ( not calling this convective feedback, per se) is the new sensitivity in this thing. Prior in the saga, it was 'How would the N and S stream ultimately interact', subtending the western ridge of N/A ..etc... Now, it seems that's settled.  But we've relayed one uncertainty into a conflict among these model types as to how complexities inside the system's gearbox will play out.

Convective physics can/do vary from one model type to the next, and latent heat budgeting therein may be relate-able in this.

 

[JC-CT]

[CT Rain]

Just now, ORH_wxman said:

It has a rotting outer band long after the storm is occluding

The omega thump on that band and even down toward Hartford is at like 400mb. Don't like that.

[PhineasC]

2 minutes ago, dendrite said:

yeah was afraid of that

I really tried to not bite on the NAM/Euro scenario of 18" here and just stick to 6-10 which every model has for both of us I think.

[weatherwiz]

1 minute ago, FXWX said:

Not an expert on the duel low scenario, but given the incredible potency of the upper levels (500 especially) I'm not sure a duel structure can last long before the surface structure gets consumed / consolidated into one very intense low???  I'm open to being schooled here, but how can a duel structure last under this upper air configuration.  As 40/70 inquired, do you have any good historic similarities?  

I share this same exact question. Going to have to study up on dual low structures after this and the processes behind them.

[JC-CT]

[Ginx snewx]

Keep disregarding the Euro at your own peril. Just sayin

[ORH_wxman]

4 minutes ago, FXWX said:

Not an expert on the duel low scenario, but given the incredible potency of the upper levels (500 especially) I'm not sure a duel structure can last long before the surface structure gets consumed / consolidated into one very intense low???  I'm open to being schooled here, but how can a duel structure last under this upper air configuration.  As 40/70 inquired, do you have any good historic similarities?  

Well it doesn't last....even on this NAM run it gets yanked back down to south of MVY....I think the biggest issue is the timing of it. I'm trying to think of any high-end storms that had something similar....2015 started to become very brieflyt elongated before being captured, but nothing like what is being shown on guidance.

[MJO812]

Have to get rid of that double barrel low

[PhineasC]

3k also does the double lows thing but seems to figure it out faster.

[40/70 Benchmark]

1 minute ago, Ginx snewx said:

Keep disregarding the Euro at your own peril. Just sayin

That is my default...gotta trust the EURO to resolve this.

[jbenedet]

6 minutes ago, 40/70 Benchmark said:

I don't think we will know exactly how those meso nuances of the cyclogenesis will evolve until they happen.

Def not. But can’t ignore latest outputs. To me confidence increasing for >12” snows in mid Atlantic while our uncertainty is increasing, especially in NNE. The mid Atlantic less affected by the east low bc they’re cashing in before it happens. They’re also benefiting from the better H5 trough intensity that’s happening early on..,hr 15 or so. Dual trends of sorts. Better earlier, worse later. Curious for sure…but not unlikely per the consistent guidance.

[dan11295]

12z NAM is not a trend you want to see if you want a high end event. Still a big storm, but lowers the ceiling. This is why the NWS didn't go too high with the numbers this morning.

[RUNNAWAYICEBERG]

Just now, MJO812 said:

Have to get rid of that double barrel low

Your avatar changes are lol. 

[PhineasC]

Just now, MJO812 said:

Have to get rid of that double barrel low

It's always something. This is why 99% of snowstorms end up more pedestrian in the end. Something comes up.

[PhineasC]

Just now, 40/70 Benchmark said:

That is my default...gotta trust the EURO to resolve this.

It might have three lows at 12z.

[RUNNAWAYICEBERG]

Just now, dan11295 said:

12z NAM is not a trend you want to see if you want a high end event. Still a big storm, but lowers the ceiling. This is why the NWS didn't go too high with the numbers this morning.

One run is not a trend. 

[Ginx snewx]

12 minutes ago, Damage In Tolland said:

No difference really in end 

Semantics look at 7h Holy death bands. Modeling cannot handle those 3 to 5 inch bands. We know full well,the roar as they approach is well before the snow. All is said and done modeling wise. Noise and something to talk about. Game time, warmup suits put away home game uniforms on. 

[dendrite]

1 minute ago, PhineasC said:

I really tried to not bite on the NAM/Euro scenario of 18" here and just stick to 6-10 which every model has for both of us I think.

That's a congrats for Ray/SE NH/dryslot.

Although sometimes these things have surprises. I just like to be close to the real goods on modeling and then let it play out. Sometimes I get a Dec 20 and sometimes I get scraped with frozen sugar.

[Zeus]

9 minutes ago, CT Valley Dryslot said:

Everyone living and dying by the NAM lol.

[FXWX]

1 minute ago, weatherwiz said:

I share this same exact question. Going to have to study up on dual low structures after this and the processes behind them.

I'm wondering if we are getting into a bit of over-analyzing?  The big footprint pattern aloft has not really changed... We might be so involved with almost model nowcasting an event before it has really unfolded, that we are in a can't see the forest for the trees mentality?

[Damage In Tolland]

11 minutes ago, CT Rain said:

Lopped like 40% off your QPF 

Queening?

[weatherwiz]

This is getting worse than severe wx weenies calling bust on a high risk before convection even develops 

[Torch Tiger]

12 minutes ago, DomNH said:

That right there is why I wouldn't be comfortable completely chucking them. There is a scenario where this has a 12-15'' floor. 

Never felt comfortable going over 18" here

[DomNH]

Just now, Torch Tiger said:

Never felt comfortable going over 18" here

I wouldn't be surprised if we got two feet. I also wouldn't be surprised if we got 14''.

[40/70 Benchmark]

1 minute ago, jbenedet said:

Def not. But can’t ignore latest outputs. To me confidence increasing for >12” snows in mid Atlantic while our uncertainty is increasing, especially in NNE. The mid Atlantic less affected by the east low bc they’re cashing in before it happens. They’re also benefiting from the better H5 trough intensity that’s happening early on..,hr 15 or so.

It seems to create a minima around CT (we know that must be wrong), before the energy jumps east and consolidates again...

1) Is that real..

2) Is the timing correct..

[Damage In Tolland]

Just now, FXWX said:

I'm wondering if we are getting into a bit of over-analyzing?  The big footprint pattern aloft has not really changed... We might be so involved with almost model nowcasting an event before it has really unfolded, that we are in a can't see the forest for the trees mentality?

I said that yesterday. Too much looking at finite details that don’t matter . This thing locked . 

[weatherwiz]

Just now, FXWX said:

I'm wondering if we are getting into a bit of over-analyzing?  The big footprint pattern aloft has not really changed... We might be so involved with almost model nowcasting an event before it has really unfolded, that we are in a can't see the forest for the trees mentality?

That is very possible...I know I find myself doing this before storms quite a bit. Sometimes I'll end up reacting and making changes to my forecast when no changes really need to be made.

[Ginx snewx]

1 minute ago, FXWX said:

I'm wondering if we are getting into a bit of over-analyzing?  The big footprint pattern aloft has not really changed... We might be so involved with almost model nowcasting an event before it has really unfolded, that we are in a can't see the forest for the trees mentality?

My point exactly.  I mean experience tells us 5H 7h 8H are perfect