Typhoon Tip

Yup, we urged taking the 'notching' and 'gap' work painted on QPF progs seriously and here we are - nailed that! Just eye-ballin' out of window, looks like 6-8"" here in N. Middlesex Co/Ayer. Respectable low-end result is a fair qualification at the moment. Seems rad has no interest in bringing SE here, or NW axis back S, and seeing as short range diagnostic tools don't either we're probably already flurries mode on this dawg. I can see 20" totals surround this axis. These notches are interesting. It's hard to say if it is purely coincidence of mid and low-level disparate physical mechanism, where a split then both avoiding this region - one being frontogenic and 'quasi' CSI, N and the other being lower baroclinic SE ... Or, is it that this region sits right in the core of barrier jet mechanics where the evaporation is higher..? I think like everything it is probably some percentage of both. I lean toward splitting the systemic mechanism as most culpable, however. I've looked back at some storms in history with the NESDIS totals product and you know it's fascinating ... I can see this phenomenon is not unprecedented for the region that aligns ~ central Worcester CO to interior SE NH. Not in every case .. no, and in fact, there's are times when this region's presented with the max as well.. But this region does gap in certain sets up, and is reproducible so it's probably a real phenomenon. The Boxing Day Event was an even more pronounced variation than this one... though this is going to be pretty striking at 1/2 to as much as 2/3rds less than NW and SE. Anyway, there are a lot of them that featured this interesting "dent" in the totals ... might be in an interesting sub-genre study - 21/20 S- (EDIT, actually we're suddenly closer to S here. I'm guessing fractals and chaos made a phone call to discuss the impudence of me daring to suggest only flurries the rest of the way here .. We'll see. I haven't been up red-eyed over this. But NCAR's wonderful gritty past-and-present product suggests we didn't really start gapping until after 5 or 6 am amid said region.. So it's interestingly suggestive of being in axis of that oreographic focused dry tongue of air cutting in underneath the growth region - I think it's both mechanical split and evaporation. )

it's also typically slanted too... The fronto-g band lags fallout after initiation due to lifting the parcel at a slant-wise trajectory blah blah...

it wouldn't shock me if even down there in interior/S NJ they have to go over to an advisory ... I bet they bullet nuggets in sideways rattle in undercutting cold bust - this high just can't be more instructively placed for dictating model error - ... look at Will's obs up there and it's cold in place, and integrated into back-built air mass that is endlessly supplying - when any pressure falls start occurring the coastal barrier jet will only intensify and bust everyone cold that is already in it - You're talking 12 F DP at TTN ...and it's only colder and deeper in the supply region... and judging by those wind flags, the llv barrier flow has already set up anyway - Probably a good time to point out that the lower 100 mb of the atmosphere is very difficult to resolve for even SREF meshing...

Yeah... looks like there's some question as to cold air supply in this - seems at 20/6 as an average BL precondition from EWR to BOS... we're in trouble -

Didn't stay up all night so I'm "late" to the morning shenanigans but ... I'm still seeing two aspects, one that is fun and one that is annoying ( potentially...) 1 ... CSI or 'quasi' CSI (Conv. Symmetrical Instability) still seems plausible if not likely in this situation - I didn't listen/see WCVB's morning report, but I do recall their layout later yesterday was a smidge less at "10-16" with no "+" symbol caboose ...so clearly, someone is trying to emphasize some form of local enhancement - ... (Edit.. I shortened that - it's too long of a read for this engagement so why bother - no one does or will ) 2 ... A tucking screw hole for Ray ? That stubborn notching is still being hinted in these products. From where I am, N Middlesex Co over to N. Essex there could result a relative minoring? There does seem to be a tendency in recent guidance renditions to fill that in... but it's still hinted/showing up around Worc. Co in the UKMET ... and Euro is hinting NE... It could be that said region is S of the said mid level 'frontogenic' forcing/CSI activity, while being too far NW of E MA's coastal frontal flop-side big snow signal. ..I could see like Brockton over to Framingham out along Rt 9 getting a surprisingly donut stuffing machine return from this, unrelated specifically to said mid level magic ... Other than that... these CSI/banding signals for me are quite elegantly designed, so without them this looks like a 10" thump... but if a band sets up... it's 4"/hr ?with thunder?

That’s interesting you get an impression from that like there’s some elevation dependency. Not sure that’s really what attributes to those local maxes. I mean this cold air is deep ... Valleys are cold too. Maybe it’s evaporation in a longer fall column? Huh.

Nuanced stretching still hinted and in order to do that it robs from vertical motion ...

It may in fact be noise ... because at this point, relative to what this thing has to work with, it’s got nowhere else to go but less ... I mean it’s maxing out what it has to work with already so anything else has got to deviate that direction. I don’t see how we can ask this system squeeze out more based on what she’s got going in

You know ? it's almost like if the storm were a little weaker, it would be better - hold on hold on. let me s'plain it. If it were weaker, we could still get a 6-8" band to about the Pike with 2-6" to Rt 2/SE NH... then, the wind on the back side doesn't bend/back around into an NVA subsidence and drying ... We'd probably sustain a feeble 800 mb easterly jet with all that mid level winds still troughing underneath our latitude after the event, and we'd have another 18 hours ( probably ) of currier&ives ...or even that 1.25 mi vis saw dust you sometimes get... It would prolong the wintry vibe - But it does seem like we get a moderate ( easily ) to perhaps top 20 Dec event ... that clears starlight by mid evening.

good humor but .. there is a matter of perspective. The GFS was actually the first guidance to flag this space and time as containing an event of interest... ? That does count.. The others caught onto the GFS' invention and ran to the accuracy bank with it.. leaving the GFS - so it seems.. I mean it does seem unlikely ..but this thing could still bust S-E and be a NYC/L.I. CT/RI and Cape thing ... You know, there were a couple of big storms in the 1985 thru 1990 ...back before modern refinement of modeling tech, where painful SE correction happened within 6 to 12 hours to go before event entry. Proooobably not happenin' in this day and age - no. But, this is still 3.5 to 4th period technically so ... we could bump 50 miles a run starting at 00z and suddenly the GFS is wrong for coming N - wouldn't that be an ironic kick in the nuggets. Ha... But anyway, fthe GFS was really pretty good at D9 to 11 range... It just seems for the time being that couldn't get out of it's own progressivity bias down the stretch ... Matter of perspective, if there is a boxing day wave in eastern N/A... that run counts as a ballsy call -

Thats where the juice is, makes sense to sample it although the budget must be shot after the season we had yeah... yet the assimilation(s) are supposed to be sufficient between Japan and California... ..I don't know, I think Satellite should electro mag resonance can see the moisture content as sufficiently packed layers for a region as small as the Gulf when we're above the 95% tile out in the Pacific - doesn't seem to add up as explanation but fug it -

wait what ? why the Gulf - you do mean the Gulf Of Mexico? not sure I understand that as a sonde gap - ... hm, was there discussion offered as to why -

I don't see a problem with Harvey Leonard's rendition here - what am I missing? As far as "pope" - you know ..I can see his misgivings on this ...lord knows I've had them - particularly early on.. But, my personal notions on this changed, and I described those pretty clearly already earlier in the day - not that anyone asked.. lol. But seriously, I don't think anyone should be derided for an outlook before anything has actually taken place. I will say though ..from where I am sitting, the 300 mb "INCREASING" jet flow exiting E away from CNE on the polarward side of a SW 500 mb 100 kt flow that is rising up and over a nascent polar air mass 1.5 deg S of that latitude over SNE... is not the deterministic models overdoing it and I disagree with Taunton or whomever wrote that ... It is likely why/where that RGEM's incredible chart topping frontogenic band is coming from - CSI wedgie from hell and don't be surprised at 4 or even 5" per hour rate somewhere and some lightning blinks...in the vicinity/under that region. That is clockwise rotation of sick, sick difluence pulling up an already conditionally unstable theta-e rich source ... It's a snow machine...sorry - but I'm looking right at these synoptic parameters and it is what it is friends - If it doesn't happen..it doesn't happen.. but maybe afterward we can prove these features didn't set up - because if they do... I don't see how an excessive band won't materialize...

Might as well just post this then...

Whatever happens... the cold is winning in this situation - period... That high and that hygroscopic density working together will absolutely pin a CF in SE zones.. Thinking KTAN then collapsing SE... In fact, if this thing were to deepen more than current progged, the sub -geo goes more N and said CF ends up collocated over the Borne Bridge - You cannot put a 1035+ nascent arctic/polar hybrid high in this consensus -modeled position and have any warm air intrusion - it just is fluid mechanically impossible without 80 kts of S flow at 950 mb or something Jovian like that -

I provided a link a bunch of pages ago... but here it is again: https://www.weather5280.com/blog/2017/01/05/what-is-conditional-symmetric-instability-csi/ It's in there... it offers a run down topically that doesn't require a thesaurus ... but you may have to do some secondary look ups, sure.

Re-iterating.. the NAM is likely already seen it's NW most position and that behavior ...and 'probable' settling back SE some fits rather nicely into its own model-climate. It brings them on board at 84 and 60 hours ... and has them over amped and situated ( typically..) NW of trustier guidance ...then, slowly comes back to pack consensus at intervals < 48 hours... It shave QPF too ... I've seen it halve the 60 hour QPF in near terms in some case... Not saying that's happening here - this event seems to be maximizing a couple of physical mechanism so..over achieving for that.. .but, should these runs start coming SE it wouldn't be a shocker...

And there it is again... of all there has been displayed, the notch has always been there

Sick of seeing this ...gotta comment on it - want it out there before whatever this thing scores, in case it doesn't for a some scorned winter lovers - That notching in the QPF/ .. related snow products? Don't ignore that - It's real in this situation. Folks are discussing the 'hygroscopic theft' of undercutting 10 F DPs underneath ... well-enough .. but, taking all these Kutchera this, and model-centric snow product that, and blending them, clearly shows a barrier jet axial dry tongue eroding into this this...and I know why - it is because the snow genesis is high up in this scenario, and that is affording a lot of evaporation in that barrier axis, ...where the restorative interior jet is organized from interior D.E. Maine and points to the Worcester Hills -... The Boxing Day storm was a latter correction and we didn't really have time to steep in this fore-shadowing of that event, but there was a clear notching phenomenon that really was guite similar to this back then, that I personally did not take into consideration and dismissed it as noise.. Well, we didn't do so well in that system, despite any notoriety - ... We ended up with 4 or 5" of arctic grits ... drifted against opposing curb slants and finned around tree trunks and tires of cars, with not much on exposed ground from that, where 20 to 24 " jackpotted S of here... and N. Middlesex was targeted by the barrier jet dry air hose in that event ... this looks similar to me.. . Don't be surprised if there is a hygroscopic shadowing in a dearth band here in the interior up through S NH.. This sort of/said notching like below began showing up two days ago and it's been a persistently recurring illustration since...

Sure ..good question... Conditional Symmetric Instability in a quick Web look up should be sufficient to elucidate that phenomenon? https://www.weather5280.com/blog/2017/01/05/what-is-conditional-symmetric-instability-csi/ This excerpt here, from that source, nicely fits this overall scenario ...etc..etc.. there are other hints and discrete aspects that also fit ...which I will leave to your devices.. "... the vertical profile must be at or near saturation. This is where the "conditional" portion of CSI comes into play. Also, note how the winds are turning clockwise, or veering with height. A sounding like the one below, if observed on the southern side of an upper-level jet streak, could be an area where the release of CSI is possible. .." In this case, we have a 500 mb SW ...100 kt wind that is turning E at 300 mb over CNE over the course of the event... and the column is going to be saturated with that pwat/S stream air riding up that frontal slope and taping into the environment... ...not gonna re-iterate but you get it.

I feel the move by BOX to expand was probably a good call this morning .. I would extend the watch into southern VT/NH/Lower Maine coast too.. The thing about this that has me suspicious for a significant impact scenario - albeit perhaps tapering, which is an unusual result relative to the gestation of the climatological Nor'easter ... - is that there is still some 80 to nearly 100kts of 500 mb jet max riding up and over the polar boundary interface/or immediately astride on the N side of the best perceived lower thickness packing that will approach extremeness somewhere within meteorological shouting distance of a WSW/ENE axis near the S. coast... Dec 2005 rings a bell ..even if it is not really in a very good total analog space for this.. .. Both had/modeled a similar very compressed thermal interface along or just S of the S.Coast...with wind max at 500 mb moving about 50 or 70 or so miles on the polar side of said interface. Why that is important is that packed thermal interface means an upright elevated frontal slope, such that maximizes UVM proficiency for any entrained parcels... A nexus of pseudo-adiabatic destablization from latent heat release/buoyancy from/during cloud explosion ... then being augmented further by superior Q-v forcing by said exit-entrance jet acting as difluence running by just to the N... This is a positive feed-back for lift. That's a lot of long words to describe this being uniquely capable of over-producing ( or in this case, performing on par - amazing!) when we have the these physical parametrics overlapping - I would also be looking for CSI.. or quasi CSI banding and thunderstorm activity too, maybe more so NE PA/ N NJ and White Plains NY ... but if James' ( tm his warm front ) 10C dt/dx really does line up across a mere 50 miles ... some of that can't be ruled out as enough mechanics "appear" still available along the Mass Pike... feeding off CAPEd air if that were not enough... This is a S/stream theta-e potent air mass being forced up a steep ascent and the synoptic evac ... and it doesn't stop there.. because I am noticing the right exit-entrance emergent jet at the 300 mb level is over CNE ... and that's sort of completing the circuitry ... Just as an 'index finger rule' ( too ...) we were always taught in the 1990's up at UML ... you tend to look for 1.5 D polar side of 500 mb wind max trajector for snow climate and even the GFS has it's wind axis cutting across the L.I. S and tho these general rules are made to be broken... mm - I could see region Amherst to BED, MA type axis doing interestingly well in this -

Personal experience with the NAM: It's passing thru classic 'NW bias' intervals for the next 2 .. 3 cycles. Thereafter, it will likely receded a couple lat/lon ticks SE ...but also shave some of QPF - ...which, I am noticing that despite other observers speaking of stronger overall synoptic evolution thru/by the region, the latter has already commenced ... part of that is systemic bias correction, but also, par of that is owing to its axis of band-back "quasi" trowal/WCB termination over cold dome, as being position NW too. Probably less than fun to try and separate those. The 0z and 6z runs were nearing 2." liq equiv+ at Logan ( for ex..) and this run keeps that location short of that number. That said, it is upping the totals at ALB over prior guidance... so there are two aspect going on, (some systemic bias correction + position differences)/2 ... effecting snow totals and QPF and so forth.. Bottom line for those using the NAM ... ( hopefully no one at intervals beyond 36 hours without a mischievous grin ), future cycles probably bump said axis' SE and take maybe another 1/5th of QPF ... which, isn't even saying either is correct - just that it is my experience that it does this moving through intervals < 60 hours.. Otherwise, it seems this run from orbit is showing what the other models are... a tendency for deamplification of the total wave space as this event is leaving... The NAM is slower to do so, where as the other extreme.. .the GFS wants to do so at least excuse imagined - I mean, it's like the model heard that a memo 'might' be written that allows it to do a-b-c, and before the others even got to read it.. it's already onto d-e-f .. That's sarcasm for the GFS is too fast to decay the kinematics ... probably ( tho not certain ), at the expense of it's own accuracy in this case... We'll see.. But, this - I think - explains what/why some of these more recent layouts of snow totaling/consensus is for the max out there NE PA/SE NY ... then a trailing off ( at little less climo-like for coastals storms in cold columns ) along the same axis nearing central MA ...etc... It's because the total system is losing mechanics during ... So when a major model refuses to budge, the end result will invariably demo that some vestige of "why" is evidenced - even if the model in question proves more erroneous over all, you can "see the point it was making" ? well, should that play out like that... that's the GFS' echo in the outcome... I think this is an important concept and philosophy during this era of models not actually controlling the future weather ( like a sci dystopian future lol ), but still being imperfect

Snow machine look

Suggest watching the 21-23rd period

Lol. Geez. Yeah I feel pretty confident the GFS is prematurely stretching this thing-...you know pulls the x-coordinate cuts into it velocity momentum. It’s got to borrow it from somewhere right? But reducing that mid-level momentum is definitely going to weaken that 700 mill bar surface underneath it and there we go - nooOO storm for you ONE YEAR!