Typhoon Tip

Correct, buuuut, as I also *(tried at least ) to point out, there are ways to offset why. Those limiting constraints I discussed are very real ... However, so is the uncertainty as to what truly gets communicated out of the Pacific. If it is very strong ... some of it will be absorbed but there'll be enough left to cause problems/get an event out of it. Assimilation tech is not the same as it was 20 years ago? Back then it was more gappy. I mean, we used to have this kind of cushion of 'still can happen' relief, because the system in question would be out near the Date Line. The population of the model initializations of the time were largely interpolated and/or supplemented by satellite soundings that were perhaps more primitive than now. The last time a system relayed off the Pacific and abruptly re-appeared on the guidance after having faded was the Boxing Day storm back in 2010 ( I believe it was..). That one appeared suspiciously like it was 'lost then found' It seems those gaps have been filled in recent times. I've noticed better performance/less morphology in handling system/storm depictions post relays etc.. Still, with the flow being fast, I suspect this re-introduces some error proneness.

First and foremost ... Happy New Years everyone. Significant impacts farther N into central or even northern New England cannot obviously be ruled out at 6+ days, but at this time ( and given the conceptual points below) a NE PA through SE NE and southern New England are implicated the most. I feel pretty strongly that these systems ( and there are really 3 in the pipe-line; 7, ~11th and ~15th) are all likely to attenuate some as these date ranges subsequently near. The reason for this is two fold, both a bit theoretical - but do offer a solid plausible basis for limiting their realized significance toward something lower than the 'magnificence' of their D10 model entertainment. The first is related to model handling of velocity saturation, a circumstance that's been reproducible during recent winters . This has been both anecdotally observed over recent years, discussed by yours truly and any others amid the 'forumsphere.' But recently at least tacitly corroborated by publications, such as Nov 30 2023, "Fast upper level jet stream winds get even faster under climate change," found in the Nature Climate Change periodical. (just one example; I'm not aware of any other formal science) Why this is prudent? Models tend consummately toward too much amplitude in the D6+ range, ... gradually losing some percentage as handled embedded wave spaces near and pass through the abruptly improving performance window around D4..5 lead. The reason for this, I believe, is because as the models are correcting the flow faster - in keeping with the above, the +d(v) outside the local wave space, robs from said wave mechanics. It's speculation on why that amplitude bias ( and there's other plausible arguments related to chaos logistics..etc..) is apparently endemic to the technology in general. I see this occurring in all guidance sources. This is a candidate scenario to express this phenomenon, and if we rob some mechanics from the S/W itself ( think 'velocity absorption') it will tend to pancake the latitude of the disturbance envelope, converting the system into more of a 'needle threader' scenario. (these are tendencies, not absolutes). This can also be compensated by the S/W being sufficiently powerful enough to offset that taxation ( heh, being rich enough). The second of the reasons, the teleconnector spread is not very supportive of mid latitude amplification east of 100W across the continent and hasn't been for long while in the projections that are based from all three ens clusters. The PNA is in fact entering negative delta during this week, and ends up negative spanning week 2. The fact that we are also attempting to eject troughs east across the continent means that the larger Rossby wave function is in destructive interference. If you loop the ens mean 500 mb g-pot anomaly products, this is likely why there is a repeating pattern during these recent days of guidance to increasingly flatten/open up the waves as they come east in the cinema. Summary: This is as of now logic. -- Should the back ground telecon change -- Should the Pacific relay enough S/W mechanical power to offset the inevitable speeding up the circulation canvas. T Of these two offsets, the 2nd one is more likely to be realized. *It should be noted that the governing mechanics for the Jan 7 event are still out over the N Pac. Graphics to help elucidate this are welcome ... I'll probably be contributing some but wanted to get this thread started. For now I suspect a middling event "precipitates" (heh) out of the total pros and cons with this Jan 7 system. I suspect that the 12z GFS may correct N ... unless it has some special handling out over the open Pacific that makes no interpretive model analysis ever necessary again ( ), which is less likely to be the case. But I'm not sure of the GGEM type intensity.. It's more likely to modulate down based on the constraints discussed above. But we'll see. There are two ways to limit impacts IYBY: Size and latitude of storm.

It’s too early to be specific, of course, but just for fun… The Canadian solution underscore what I was saying early about the sneaky wind potential. There could be like a 2 to 3 hour period there east of Worcester over coastal southern New England where they get battered pretty good with wind gusts and sideways snow in that solution

Meant to respond a Tauntin’ ha ha ha

You guys seem to respond to whatever image you’re seeing with no larger perspective. Weird It’s an encouraging GFS run for obvious trend potential/reasons

That’s not the take away… The take away is that it’s in flux man.

Huge changes in the total synoptic handily across the continent with regard to the 10th on this GFS run

Previous run was better by 10% or something

This may have a sneaky wind issue for the Massachusetts coast and along the Long Island sound. There’s just enough pressure well there and up against that high-pressure over Quebec …there’s gonna be a decent gradient there.

Anchoring high pressure like that is something we haven’t seen in years.

Interesting … seemed to start out that way but ended up the same

Looks N of previous

Bears no likeness to the others

Above all else ... right. Nice to have a "Fantasy Warning" issued LOL... We'll see how it goes. Frankly, I'm not particularly fond of any of these events to be honest. But my concerns aren't surrounding p-type. The telecons are going the wrong way from multiple sources. That's A. In fact, the textbook interpretation has each one of these losing that support in successive order, heh. Yet the operational runs have there magnitudes in the opposite order. It is what it is I guess. B, this is my own supposition so tfwiw: model amplitude bias may shock some as the scale of these come into nearer terms and we lose some 20 .. 40% of their magnitude. The speed of the flow tends to be slowed by guidance, and speeds up from D 9 to D 4. The speed up takes storm mechanical energy away and give it back to the baseline velocity anomaly. This is an aspect I've noticed since ...2010 really, about winters. The core months get speed saturated and we see this energy exchange. All the models do this... Yes, I think I'm the only one that notices this kind of excruciating detail because I have no life. But this why systems tend (not always) to be weaker when they come through that D4.5 model performance window.

I agree ... this storm in the Euro has the option of containing a broadly expansive mix region, with snow to start going over to a rattling off the eaves and bouncing down windshields. Freezing an option too but more likely a tall IP column. Could see the interior with IP clumps even at 25 F. That high will likely tank the hydrostatic hgts below the 700 mb level though. I'm saying this just purely because there is unusually ( what's new ) warm air south of the storm track, while the 500 mb trough isohypses remain open while the trough bodily passes NW of the region. A 700 mb warm intrusion isn't a bad idea here. it is not abundantly clear that the exertion/rearranging of the -NAO ( be grateful it's western limb or we could be cooked with NY state transit), but if that begins to exert during the week and the 500 mb squeezes more S than we ... there's time for that too -

This could be a rattler. There’s room for this to correct north, but I also think that it’s going to run into a cold wall… In no small part related to what we were talking about yesterday with the falling polar field indices beginning to exert on the field, but more practical terms you’ve got cold surface high situated nearly ideally to the north - flipside of the same coin. Might create a broad mix zone.

I frankly like the GEFs being slightly progressive at this range because it fits that model system’s bias heredity

Yeah agreed mention that yesterday… Had a midwinter tornado outbreak look in that GFS run yesterday so not surprising here. If this weird long wave stretching shit continues to play it’s going to end up causing tremendous sheer/instability cross up down there.

Don't be surprised if the 7th entity ends up like the 4th as we get closer to that date, too.

I can imagine that sentiment would be shared among the local faithful. ha

That would probably be a Cleveland exit into eastern Canada in that look.

What I suspect is going on here in driving the current sensitivity is a bit theoretically challenging ... But, the numerical telecon say no way on siggy storms E of 90 W. We really should be seeing the evolution of a 'thaw' climo/ridge. I think what's happening is a compensating for the former, by surplus speed of the flow. It's mechanically stretching the -PNA configuration causing an exceptionally broad ( 'REAL') Rossby wave length. So broad that it almost "clicks" the mode around. That's typically a very unstable wave length. I believe if the flow were to ease off the throttle, the wave length shortens a little and the actual N/A pattern structure would then look more -PNA correlative. You don't typically have positive geopotential height anomalies NE of Hawaii and have negative height nadir so deep through the Lakes region - that's out of phase. I guess I am saying all this because, these storms are not really supported by theoretical spatial/synoptic meteorology, rather appear to made from the idiosyncratic nature of that unusual flow structure above. It doesn't lend to confidence in general.

Stepping outside the sandbox for a moment ( ... or maybe 'litter box' is apropos ), this EPS mean looks like March 1993. Triple stream phased planetary low event:

We've basically covered all that, already. It's nice to cite NWS I guess ...

Hey Will ... if you're lurking, do you have that PSU link for the historical model runs? I seem to have lost that. I'm keen on this Jan 7 thing because in reminds me ( in the general mid latitude circulation manifold) of the Dec 2005 10. NCEP's map library has the chart but it's the 12z only and I was wanting to see it closer to the 00z - I think your site has those?