Typhoon Tip

It was ... and the 500 mb is significantly colder in g-pot hgts as the wave space compresses through PA than prior runs. ... I mean this thing is still 8 days out -

I read the weekly publications from the MJO desk/NCEP ... They often describe the MJO correlations as being in competing or 'destructive interference' with the "on-going El Nino response" umm

(psst, i think there's a chance that whole system decays into sw flow producer)

wrote about the same exact thing re the 6z ( last page..). It's like comically perfect. It's attempting to model the elusive 'synergistic' event, the one that is supposed to be unknowable and catches everyone by surprise and snows double all leading indicators. haha. Man, what a coup de etat if it succeeds

Repeated the 6 z as far as I can tell ... (I've rejoined work work, though ... so my analysis is cursory)

ICON is basically the perfect way to maximize snow proficiency out of an attenuating ( weakening...) total wave space. That's a weak but still anomalously juiced Miller A response ( initially) that gets captured by a NJ model rapid deepener. I mean if you look at 500 mb, it has a flat wave geometry ... however perfectly aligned in torpedoing along the quintessentially ideal latitude of 1.5 deg S of L.I. for climo frontogenic forcing along the Pike. The end result of all that is that the ICON's 6z solution is attempting to actually forecast synergistic over-achievement. That's probably snowing 3.5"/hr rates for 4 hours between HFD and BED Mass out of a mere neutral standard deviation 500 mb synoptic look, by colliding these metrics. That's impressive for going shopping in a German candy store LOL

George! George! George!

thank you very much!

Well ... I'm not speaking to where the storm actually tracks. That disco above is really just regarding the expansion of the lift (synoptically) .. where those jet fields align implies the area. snowing vs dry air battle notwithstanding

-AO/-NAO ( now include -EPO in that ...), with a -PNA. But also, I checked and the WPO projections are still tanking mid month in all 3 major sources. That's going to transmit the AB phase across the Pacific circulation mode (higher heights N over cooler heights S) and almost invariably that precedes either a +PNA ...or a hybrid -PNA ( 2015 February) I'm actually more optimistic at this point than I have been for a mid winter month in years quite honestly. If this were me 15 years ago on Eastern I'd have started a thread about a potentially cold stormy era lasting 15th to 25th of the month - but popularity for those extended risk assessments has since turned into bundamentalism so I don't bother LOL

One aspect that we less often cover as a group in this engagement are the mid and upper air jet mechanics. But the overlay of the 500 mb and 300mb do indicate at least a somewhat favorable synoptic divergence potential in that layer. There is a fairly strong wind max/arc entrance region exiting Maine as the more mid level exit jet region is approaching L.I.-ish. That gap is a teeny bit larger than ideal... still, it may be close enough to enhance lift over the top of where the 700 mb is forced over the cold conveyor belt. I could see light snow farther N-W due to that "mid and upper air magic" . We're still 5 days away. It's probably more appropriate once we get closer.

Right on.. You know, I was amusing to self that this may go through a curve of attenuation followed by a kick back. We lose 30% ...owing to that correction shit, then your bold aspect kicks in and we get maybe half what we lost back. Warming to Advisory to very low end warning lol

Yeah, I don't know about the 10th-12th ( probably does bias on the front side of those days given to the fast footed pattern...). There is narrow window in the larger mass fields to have that happen, but its closing. By the 12th, the -NAO block is already retrograding to D. Straight, which back exerts a shit ton signal for NW flow into Ontario ( mid/u/a ), which would impose obviously confluence/implicity higher surface pressure. The NAO is notoriously poorly handled. Even in the better modeled behavior patterns there are nuance headaches. Also, that event may become victim to system attenuation as it nears. A weaker system would end up along a more southerly route. And you can't think in absolutes - it's not a matter of Detroit versus Worcester. But even a idiosyncratically weaker total wave space ( due to model correcting in shorter terms) moving into an initially colder environment ends up more triple point. Just some thoughts on that particular event... It's very early.

I'm a bit leery that these 'weaker' profile depictions overnight might be real and/as part of that attenuation business I was discussing in the thread opener. Not certain of it ... just leery. I will say that I agree - this thing caps out at moderate. That much is systemic, anyway I'm also noticing that there is an innocuous S/W that has gained subtle strength hot on the heels of the Jan 7 wave space; it may also be introducing some negative interference.

Looks like 1-3” Rt 2 to Pike, 3-5” along the Pike and 5-8” S of there on that run. Quick mover.

It's bit theoretical but a deterministic problem with this 7th system is that it is at the far east end of the R-wave signal. That's like the flop end of a hose - metaphor obviously. This system reaches the greatest constructive interference depth actually back around 100W and is attenuating in the deep layer, buuuut ...it doesn't encounter the baroclinic instability/'gun powder' atmosphere until it reaches the EC.. It's not in ideal phase wrt to the super synoptic wave signature. Systems that collocate these two aspects, greatest feed-back with developmental cross-sections are actually comparatively easy to call. I know it's hard to believe after the last 5 years but we've actually had those on the EC before - easier calls from 6 days out actually can happen. Because this is developing at the attenuating end it doesn't have the surrounding mass field to anchor it from "feeling" tug and pulls from surrounding perturbation in the flow. You get these run to run shot gun tracks. Just to re-iterate ... the main difference between all these solutions really hasn't been in the magnitude of the system. They're all middling Nor'easterns with perhaps moderate impact ... the problem is where precisely.

It's this recent -EPO ... slated to go positive, but as I was discussing above ... newly projected to go back negative by mid month. I've noticed this in the past - pretty sure we've discussed it as a group. It's better not to lock in a teleconnector mode and have it become static, but to have them oscillate? We're spitting -EPOs over a 7 to 10 day periodicity or something like that and it's giving the middle continental latitudes a steady diet of unbalanced baroclinicity. That's basically a storm petridish. I think having the EPS' NAO over the western limb as opposed to the GEFs, which looks more neutral/E is significant because so long as the NAO doesn't become too weighty and thus suppressive for its own rights ... Basically that's how we turn a -PNA into the stormy index mode that this recent +PNA failed like the Patriot's season to do.

We will .. I mean D6+ is far enough ahead that it's probably more academic that there are disagreements. I'll tell ya, ... if you compare the Euro to the GFS (this 12z run) the differences are almost entirely spatial. The actual mechanics are not really sufficiently different enough to imply a different result based on that alone, but the GFS has it's 500 mb trough structure approaching the lower M/A whereas the Euro's is approaching the upper M/A. That's really the difference here. The GFS does have a weaker surface response to all this by some, but ... say it were N like the Euro, it would carry at least a pedestrian albeit regional snowfall across the area. This 12z guidance suite appears to be more about "where" ... less so about "if" a system will be on the charts.

yeah, I'm just trying to show that the Pacific signal has recently begun to change toward helping our cause with that. But it'll be mid month... I mean we might have to deal with 3 or 4 days of AN ... it's part of the business. But the lease looks a lot shorter at the moment.

I started to a thread for this system - fyi ... I want to take a moment to discuss a major overhaul to the hemisphere beginning to emerge. It was a distant typically 'iffy' signal before, but around 3 days ago it started accelerating into coherence. Now we are seeing -1 to as deep as -2 SD WPO anomalies emerging in the telecon projection. This is also happening nearly in tandem with an emerging tendency to 'sag' the EPO back negative. You might recall ... I recently was concerned for a major warm up heading into mid month, possibly compensated by a -AO/-NAO. The -PNA/+EPO signal ( previous) is a Pacific warm signal that was diametric to a cold polar domain exertion. Very interesting... However, now the Pacific appears to be collapsing the other way - new but real. A newly defining -d(WPO) --> -EPO sends the Pacific arc into the 'AB' phase. The expectation therefrom materializes ( or tends to ...) blocking N overriding colder heights uncutting. This also tends to raise heights over the Alaskan sector ... all prelude to +PNA. That sequence of events is the natural propagation of the R-wave distribution. It was all missing up until 3 days ago but here we are with what really looks like a wholesale change. The -WPO crash in the telecon forecast during the ides of the month, and what is interesting is that the EPO starts actually sagging prior to any transmittance of that WPO signal into the N-NE Pac mode. That's flagging a constructive interference being position in wait. The two of those together is interesting after the 15th of the month

agreed very much. I saw that 12z GFS solution and was like ya whatever. With all the background knowledge we have wrt to how that model behaves with longitudinal trajectories at this range. How often are marching back NW with that model moving from D7 to D3 ? etc etc. There are reasons to be leery of a flatter solution happening - which can be compensated for more power in situ to the S/W itself. This Euro solution may be opting for that. But in either case, 'where' it exits the ECoast, I don't see any reason the GFS solution has to be more likely.

Yeah, I'm not too worried about the GFS southerly whiff - that's not a-typical considering that model's heredity. I'm just more concerned about keeping expectations in check. I think there's a real system here ( duh ) but there are very really arguments to keeping it middling in nature.

If the GGEM and GFS' respective handling of the NAO domain are more correct, there is no 10th event for this region of the country worthy of much discussion. I don't see how that system can survive to unfold a colder result with a -PNA and an NAO that has gone and done what most do - pull the rug out from under needing it to actually be real. There is a -NAO there ...but it's gone toward the eastern limb which cannot work in the R-w signal where the PNA is negative. Can it change back? absolutely...

If your interested .. I outlined some of the reasons (theoretical) for why that may be the case over in the thread I just put up.

(GGEM + GFS)/2