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Tracking Jan 7 coastal storm. Lingering compression/flow velocity has not lent to consensus, but it seems at 30 hours out.. finally?

Typhoon Tip

By Typhoon Tip,
in New England

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Baroclinic Zone
Baroclinic Zone

This should cover it.

HoarfrostHubb
HoarfrostHubb

All those cars I see in the morning must be going to the pot shops

CoastalWx
CoastalWx

You don't even need fancy fronto maps to see where pound town is below. Look at that inflow at 50-60kts slam into the s coast with lighter winds to the north. There is your front and convergence. Air

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Typhoon Tip

Typhoon Tip

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1 hour ago, Lava Rock said:

with how bad the models are, you guys should get a partial refund on your subscriptions^_^

Seasonally ... ?  - perhaps.

( Sorry ... wasn't a part of this conversation's immediate history but just an ob on model performance) 

The GFS has been reasonably consistent.  

The GGEM has been reasonably consistent.

The Euro has been reasonably consistent. 

The problem is... the GFS does not agree with the GGEM, nor the Euro. 

The verdict is still out regarding this particular storm, which I feel - full disclosure - like the Euro and GGEM are likelier to succeed, given to some abstractions/ personal observations regarding GFS biases since these recent new version releases.  That's by know means a declarative -  ...

This is a unique situation.  As I outlined yesterday there are two points of handling contention: 

The first being ... there is a majority/ multi-model cluster consensus for the SPV,  situated initially over the NE Pac/GOA region, to getsdisrupted - beginning at ~ hour 24 from the 06z initialization. After which, that's when things get complicated.   En masse, the SPV gets 'split' ..   All models/blends there in, essentially portray some percentage of its vestigial mechanical power as retrograding W under/along the EPO domain ( I annotated this in the charts a few pages back/yesterday if interested... ), while the rest of it gets bumped down stream over N/A mid latitudes - consequentially giving rise to whatever does ultimately manifest along the E/NE coasts.   Correctly handling the ballast of that vorticity shearing/ conservation is like trying to predict which way an egg will roll off a ruler's edge, when starting from a position that's more or less precisely balanced. 

The second aspect ... regardless of 'how much' gets ejected downstream post the split, as it is nearing 100W ( about 2 days from 06z's initialization), the rapidly rising PNA offers some known model error prone as to the fuller( lesser...) extent of the aft region of ridge response.  That is part of the total wave length of the storm - for those less privy. If immediately on the tail of the S/W ( say ...nearing Iowa), the ridge bulges more, the S/W will dig more. 

Now ... I am not entirely sure about the following notion... but from what I have been observing it "looks" as though the GFS is taking more of the SPV, post split, westward with the retrograde motion...  Contrasting,  the Euro and GGEM take crucially more so southeast.   

By the way, if one bothers to look at the 12z yesterday morning GGEM and Euro evolution, and compare them to the 00z, you can see how handling of that ridge in aft region of the S/W ejection is excruciatingly sensitive.  Ever so subtle in the Euro, perhaps a little more coherent in the GGEM, those heights are higher, and they've slowed the progress of the total cyclone space, while adding intensity - just from slightly higher ridge heights across those cycles.

I can't stress enough...this is a very powerful wave in these higher resolution models.  Really even the GFS .. But is' flatter wester ridge appeal, ...it's sort of maybe "manufacturing" it's on destructive interference, whilst the other models are trying to reduce that offset factor. 

The Euro is < D5 ... mm.  All the models are at 48 to 60 hours lead, for whether there will be a real S/W over the CONUS at all, so that pretty much wipes out any remaining doubt in my mind as to "weather" we'll see a storm evolving here.  Switching the title of the thread to 'tracking' as opposed to 'potential'.    It's also helping that the -PNA --> +PNA, emerges a negative teleconnector centered on the OV, both numerically in the GEFs derivatives, but also spatially in the pretty art of the EPS/GEPS/GEFS graphics, that really also nods to the logic that the GFS is again fighting the consensus as an outlier - perhaps even the very physics of the mode change.

There is an interesting irony about this ... The Euro and GGEM have generationally been more guilty of leaving behind mechanics... while the GFS has a kind of genetic lineage to be more progressively biased.  These models types have improved over subsequent versions ... but from time to time one can still get a vague sense that their tendencies still lurk.  This is a situation where respective camps appear to modus operandi.

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Cold Miser

Cold Miser

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1 hour ago, MarkO said:

Not sure if this has been brought up, but can't believe the number of schools closed or on delay this AM. I think it's more of "we need one more vacation day".

The school where my girlfriend works (and hubbdave also) they delayed the students coming in so that teachers could obtain covid testing...teachers show up on time, students come in late.  At least that is the way I understand it there, as well as some other districts.

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Typhoon Tip

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4 hours ago, MJO812 said:

Gefs starting to trend to the amplified solutions.

gfs-ememb_lowlocs_eus_18.png

gfs-ememb_lowlocs_us_19.png

Thanks for posting this ...as I'm late catching up this morning -

I noticed the rather impressive leap of the GEFs mean ... back toward more impact implications/  EPS look, compared to the previous two cycles. 

The EPS has been more consistent - as others assuredly either know, or should be keeping track. The GEFs being less so, but recently leaning toward acquiescence is probably a red flag against the operational for this particular system.

NO, I don't think this is a crisis for the model the rest of the winter, either -

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3 hours ago, ORH_wxman said:

I actually like where this one is right now. You have pretty much all non-GFS guidance with a significant storm and the OP euro is on the western side of the EPS envelope. The classic 70/30 or 80/20 compromise would be ideal. 
 

Too bad it’s not 3 days out instead of 4 though. 

There's some era relativity there ...

You know, ... given the state of the art of modeling infrastructure/ .. 'AI' and a circulation less saturated with gradient and velocity, D4 would incrementally more confidence than any D5 ..That was always the critical performance 'trust' threshold of the Euro. 

I do want to get on the other side of 30 hours.  As I wrote - probably too long for many read... lol - last hour, there are is contention as to what and how much of it gets ejected out of the NE Pac SPV breakdown.   The GFS is either going to win probably the greatest coup attempt in the history of modeling ... or, lose in that debate. 

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16 minutes ago, qg_omega said:

Icon has nothing

In the eventuality that is storm comes to actually verify ... more so than less, I really don't think this ICON model is going to even see it until the model runs beginning ~ 30 hours from now. 

Prior to that, it seems to have very little assessment as to how the SPV over the NE Pacific will be forced by the PNA mode change - I suspect that has to do with the ICON technically being a meso model ( on 'roids as it were ) and not seeing the domain over the Pacific that is ultimately driving/responsible for said PNA evolution - it's a question I'm wondering.... 

In other words, outside of its spatial domain.  I wish I could see the hemispheric scope of the ICON ...but, being that it is the ICON and I have not seen it perform very well, anyway, over the longer term for just about anything I've seen that is mid range <-- to short range relay, I'm not really inclined to bother.  I have read a little about it... According the German org that hosts it, it is a Icosahedral Nonhydrostatic model - basically, ... take the Earth, and cut it up into a icosahedron ..well... one can find all here:

https://www.dwd.de/EN/research/weatherforecasting/num_modelling/01_num_weather_prediction_modells/icon_description.html

Anyway, I'm just wonder how seamless these jigsaws are, considering that the PNA covers a bigger area than 1/20th of the spherical surface area of the planet.  Just speculation here , but if the PNA mode change is not integrating properly across the conjoining polyhedron regions, then it may not be driving the SPV split event right -->  shitty returns over eastern N/A mid latitudes.... 

Or, it's on to something...  I don't know if the simpler explanation is really bearing truth in this particular instance, however.

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