Monday 12/2 Threat Disco

[NorEastermass128]

ACY burial

[JC-CT]

It is pretty cold out there. Models seemed to underestimate it a degree or two.

[EastonSN+]

12 minutes ago, Typhoon Tip said:

Heh... I just returned late last evening.  I think I made it pretty clear I was heading out of town for the holiday, and probably wouldn't be reachable ?   At least I thought I did 

Anyway, interesting system here, but there are some distractions to consider.   I'm not fully onboard after getting caught up with trends over the last three days that a double hit/impact scenario is a "definite" on the tote-board. It could be a passe characterization deal, annoyingly subjective that starts fights in reanalysis and  imby opinion making.  Tongue in cheek there... but, there are scientifically appropriate limitations for the double-whammy idea.

Namely ( one ) despite the "cut-off" structure of this, the progressivity of the flow is still there. I've read back a few pages; there's some tendency to conflate that appearance of this vortex with cut(ing) off.  That's not reeeally what's happening here in terms of what it typically means to cut-off a mid level vortex due to total wave space/cyclogenetic feed-backs from UVM/thermodynamic processing ( deepening the core to the point that internal heights fall beneath the trough's ambience) a time span amid the coastal low model in which they tend to do their most damage.

That's hint number one that in general...this could behave oddly; hence a bit distracting.  This is already closed off, progressively rollin' along, and therefore toting along already occluded structures with it. 

That said, yes ... it's still getting some kick-backs from cyclogenesis/processing ( particularly exemplified in the 06z's "however" quite bizarre total behavior surface and/to aloft).  The 500mb surface plumbs to 528 or a touch beneath, and moves from S of ISP to east of PWM out there between 36 and 48 hours, ... a rather ideal climate track actually for Worcester up to SE NH; even if the deepening is modest from around 534 that is true.  Climate alone on the mid level "magic" egh... little dicey here. Kind of off-setting flavors.

The next distraction:  Both the speed of the flow surrounding the trough, combined with the fact that the trough is so anomalously large, are imposing an interesting(anomalous) surface evolution tendency along and off the Mid Atlantic to east of Cape Code.  Those two factors working together arrange for cyclogenesis parameterization to excite a "premature" low along the Delaware/NJ lat/lons, which reading back several pages folks are referring to event #1?  

That spin-up is a wave along a quasi warm front ..fine, typical detonation point for 2ndary and so forth anyway, if not along a triple point, that's understandable.  However, this is happening way out ahead of our deeper later/better mechanical forcing associated with the vortex. I guess a simple way to say, the 2ndary Miller B model is being unusually stretched (circumstantially) here.  The mid level velocities way out ahead of that better forcing are high, and this increasing in time is acting like a diffluence ...floating a match over gas fumes, igniting a surface low that then becomes problematic:  It is sufficiently capturing the baroclinic field and strips a good bit of it away seaward in the extended rich velocity field. Then of course the more important Q-G forcing associated with the closed vestigial trough/vortex approaches that same area, but ends up initially challenged to detonate a new/'real' supportive low.

That's why we are seeing this tendency in the GFS and NAM to belay the new, I guess we'd have to call it "tertiary cyclogenesis" in this case.  Fascinating how the 06z GFS tries to atone by capturing and foisting a long seaward exposed low way back NW toward the Maine coast Tuesday morning.  Man, talk about a model suffering a migraine!  

Thing is ... these models don't really depict scenarios that are 'physically impossible' ?  No ... they are still governed by the principles of geophysics in their make-up... We can only deduce which outcome is more or less possible based upon experience, climate/empirical past, local time-scale trends/seasonal tendencies, education, and yes ... a bit of art ( ha, sometimes the latter happens too liberally in the weather -related social media, too, but that's another story...). 

We've seen premature ejaculations many times in the models along the M/A spanning yesteryears in the modeling behavior.  Troughs encroach hyper volatility scenarios/set-ups and we've watched successive model runs correct toward a more cohesive western low as the near term came into focus.  I don't know about that, this time, however.  The hotness of this prom date is there but ...this trough migration and quasi-closed vortex (again) being so anomalously large, along with unusually high mid and upper level wind speeds surrounding its rampart approaching a sexy deep layer baroclinic field presently situated(ing) along and off the M/A is certainly a viability for early ... ah, fun.  

Heh..so I'm not readily sure the typical westerly correction vector applies because of this total scenario's uniqueness.  But if the first low does develop earnestly ... I wouldn't be shocked if the 2nd system ends up E.  .

 

Welcome back!

Can anything save CT from getting skipped over while Philly and Boston get pounded!

[ORH_wxman]

1 minute ago, EastonSN+ said:

Amazing and Eastern mass getting hammered at this point

Looks like E MA gets another 2-3" after this point Tuesday morning on the meteocentre site.

Reggie is also shoving the sfc front way too far inland...it has ORH raining for a time while CEF is snowing....that is pretty much guaranteed to never happen unless you bisect the mid-level warming between them which isn't the case here.

[RUNNAWAYICEBERG]

UK has lead the way with the NJ/PA stuff for days.

[bristolri_wx]

Wow, still a lot of model variation less than 24 hrs out. Impressive.

[Spanks45]

1 minute ago, ORH_wxman said:

Looks like E MA gets another 2-3" after this point Tuesday morning on the meteocentre site.

Reggie is also shoving the sfc front way too far inland...it has ORH raining for a time while CEF is snowing....that is pretty much guaranteed to never happen unless you bisect the mid-level warming between them which isn't the case here.

It clearly has that band developing to the west of that low, if that low is 100ish miles to the east, then it sits right over CT, probably has the right idea of some sort of awesome snow band, but exact location is TBD...

[DavisStraight]

18 minutes ago, Typhoon Tip said:

Heh... I just returned late last evening.  I think I made it pretty clear I was heading out of town for the holiday, and probably wouldn't be reachable ?   At least I thought I did 

Anyway, interesting system here, but there are some distractions to consider.   I'm not fully onboard after getting caught up with trends over the last three days that a double hit/impact scenario is a "definite" on the tote-board. It could be a passe characterization deal, annoyingly subjective that starts fights in reanalysis and  imby opinion making.  Tongue in cheek there... but, there are scientifically appropriate limitations for the double-whammy idea.

Namely ( one ) despite the "cut-off" structure of this, the progressivity of the flow is still there. I've read back a few pages; there's some tendency to conflate that appearance of this vortex with cut(ing) off.  That's not reeeally what's happening here in terms of what it typically means to cut-off a mid level vortex due to total wave space/cyclogenetic feed-backs from UVM/thermodynamic processing ( deepening the core to the point that internal heights fall beneath the trough's ambience) a time span amid the coastal low model in which they tend to do their most damage.

That's hint number one that in general...this could behave oddly; hence a bit distracting.  This is already closed off, progressively rollin' along, and therefore toting along already occluded structures with it. 

That said, yes ... it's still getting some kick-backs from cyclogenesis/processing ( particularly exemplified in the 06z's "however" quite bizarre total behavior surface and/to aloft).  The 500mb surface plumbs to 528 or a touch beneath, and moves from S of ISP to east of PWM out there between 36 and 48 hours, ... a rather ideal climate track actually for Worcester up to SE NH; even if the deepening is modest from around 534 that is true.  Climate alone on the mid level "magic" egh... little dicey here. Kind of off-setting flavors.

The next distraction:  Both the speed of the flow surrounding the trough, combined with the fact that the trough is so anomalously large, are imposing an interesting(anomalous) surface evolution tendency along and off the Mid Atlantic to east of Cape Code.  Those two factors working together arrange for cyclogenesis parameterization to excite a "premature" low along the Delaware/NJ lat/lons, which reading back several pages folks are referring to event #1?  

That spin-up is a wave along a quasi warm front ..fine, typical detonation point for 2ndary and so forth anyway, if not along a triple point, that's understandable.  However, this is happening way out ahead of our deeper later/better mechanical forcing associated with the vortex. I guess a simple way to say, the 2ndary Miller B model is being unusually stretched (circumstantially) here.  The mid level velocities way out ahead of that better forcing are high, and this increasing in time is acting like a diffluence ...floating a match over gas fumes, igniting a surface low that then becomes problematic:  It is sufficiently capturing the baroclinic field and strips a good bit of it away seaward in the extended rich velocity field. Then of course the more important Q-G forcing associated with the closed vestigial trough/vortex approaches that same area, but ends up initially challenged to detonate a new/'real' supportive low.

That's why we are seeing this tendency in the GFS and NAM to belay the new, I guess we'd have to call it "tertiary cyclogenesis" in this case.  Fascinating how the 06z GFS tries to atone by capturing and foisting a long seaward exposed low way back NW toward the Maine coast Tuesday morning.  Man, talk about a model suffering a migraine!  

Thing is ... these models don't really depict scenarios that are 'physically impossible' ?  No ... they are still governed by the principles of geophysics in their make-up... We can only deduce which outcome is more or less possible based upon experience, climate/empirical past, local time-scale trends/seasonal tendencies, education, and yes ... a bit of art ( ha, sometimes the latter happens too liberally in the weather -related social media, too, but that's another story...). 

We've seen premature ejaculations many times in the models along the M/A spanning yesteryears in the modeling behavior.  Troughs encroach hyper volatility scenarios/set-ups and we've watched successive model runs correct toward a more cohesive western low as the near term came into focus.  I don't know about that, this time, however.  The hotness of this prom date is there but ...this trough migration and quasi-closed vortex (again) being so anomalously large, along with unusually high mid and upper level wind speeds surrounding its rampart approaching a sexy deep layer baroclinic field presently situated(ing) along and off the M/A is certainly a viability for early ... ah, fun.  

Heh..so I'm not readily sure the typical westerly correction vector applies because of this total scenario's uniqueness.  But if the first low does develop earnestly ... I wouldn't be shocked if the 2nd system ends up E.  .

 

Looks like that's been the trend east for part 2

[Typhoon Tip]

3 hours ago, EastonSN+ said:

Welcome back!

Can anything save CT from getting skipped over while Philly and Boston get pounded!

I haven't looked at that particular guidance as of late... not this morning either, so I'm not sure why that is there with that "bite" out of the QPF look.  It doesn't make a lot of "spacial" reasoning sense, not when combining all guidance that I have seen, together with climatology and experience with coastals and closing mid level circulations off actually S of CT ... The 700 mb level has an axis S of both CT/RI so it's interesting that the NAM has had so much warm intrusion going on -... particularly considering the high in eastern Canada; not appreciably massive, no...but, 1020 and holding is certanly enough to continue to ageo the interior right down the CT valleys and probably up through the 850 mb either way, the whole duration to me. 

That's the conceptual 50,000 foot perspective from my chair on this. 

[RUNNAWAYICEBERG]

Just now, Spanks45 said:

It clearly has that band developing to the west of that low, if that low is 100ish miles to the east, then it sits right over CT, probably has the right idea of some sort of awesome snow band, but exact location is TBD...

Ray is confident this will slide east more. I trust his weenie.

[JC-CT]

5 minutes ago, EastonSN+ said:

Welcome back!

Can anything save CT from getting skipped over while Philly and Boston get pounded!

 

Just now, DavisStraight said:

Looks like that's been the trend east for part 2

Omg you don't quote the whole thing

[JC-CT]

I'd be lying if I said I'd be unhappy with the gfs outcome

[Typhoon Tip]

3 hours ago, DavisStraight said:

Looks like that's been the trend east for part 2

Yeah perhaps ... but, I should also be clear:   what I mean is, "if" we end up with an initial/#1 coherently separate event, any 2nd one might end up E. 

I don't even know if these won't exactly consolidate - it's just a distraction/possibility to that needs to be considered is all ...

[PowderBeard]

32 minutes ago, HIPPYVALLEY said:

Elevated valley location with higher hills to my W and N.  I'm around 350'.  I often do much better than the S valley but I'm not convinced of the higher QPF totals with this complex of a set-up.   I could see this area going 5-7" for round one and 3-5" for round two.   

You being further N will help. I'm in some higher terrain of Belchertown and would love the RGEM to be correct but thinking 4-6" round one , dry slot since we are east of the river, then maybe an inch or two extra. No matter what happy to start December with white. 

[JC-CT]

Ok, but the gfs. Guys, the gfs just saved winter.

[dendrite]

GFS pounds ENE pretty good. heh

[dryslot]

[Damage In Tolland]

How’d the FV3 handle it? 

[Greg]

Yeah, this gives Eastern Mass the goods it wanted.

[STILL N OF PIKE]

11 minutes ago, ORH_wxman said:

Looks like E MA gets another 2-3" after this point Tuesday morning on the meteocentre site.

Reggie is also shoving the sfc front way too far inland...it has ORH raining for a time while CEF is snowing....that is pretty much guaranteed to never happen unless you bisect the mid-level warming between them which isn't the case here.

This is how I envisioned the earlier capture when I was replying to Dry-slot an hour or two ago. That retro west of MSLP from east of ACK to a temporary stall of CHH would likely demolish E ma/ SE NH / Portland 

[Typhoon Tip]

So, naturally ... if this lead/#1 detonation is less effectively stripping the baroclinicity eastward, than a 2nd low could certainly evolve back closer to the coast..

Boy the 12z NAM narrowly misses Eastern Mass with choking snow. I know I'm convinced the more I look at this that I'm right about this tho.  This lead gawking snow and early low sequencing is actually a detriment to what could be a better performance - in total.   I mean, as modeled.... it's going to to be interesting to see what happens of all this.  nice.. On Dec 2 ... fuggin early folks.

[dryslot]

Just now, STILL N OF PIKE said:

This is how I envisioned the earlier capture when I was replying to Dry-slot an hour or two ago. That retro west of MSLP from east of ACK to a temporary stall of CHH would likely demolish E ma/ SE NH / Portland 

That is correct.

[weathafella]

10 minutes ago, JC-CT said:

I'd be lying if I said I'd be unhappy with the gfs outcome

 Shellacking for us her Boston!

[ORH_wxman]

Just now, STILL N OF PIKE said:

This is how I envisioned the earlier capture when I was replying to Dry-slot an hour or two ago. That retro west of MSLP from east of ACK to a temporary stall of CHH would likely demolish E ma/ SE NH / Portland 

Yes it would....GFS does it too except it's a little further east of CHH.

 

 

[WinterWolf]

2 minutes ago, dryslot said:

I’ll take my 15” and be very happy!  Thank you GFS.

[NorEastermass128]

AEMATT

[RUNNAWAYICEBERG]

2 minutes ago, Damage In Tolland said:

How’d the FV3 handle it? 

We haven’t wavered from our 8-12” call with lots of pinging for the 84 corridor and 12-16” for the nw hills. 

[Typhoon Tip]

You know what...

we might actually be looking at a short window correction west after all...   We've seen this countless times in the past.  I mentioned this in that diatribe's ending thoughts, but the speculation is that this unusually large circulation size and fast mid and upper level wind speeds might be over -sensitively generating a lead wave too much in the guidance. 

Might be seeing that phasing out... The GFS still strips tho - but, we'll see how much that looks that way 18z and 00z ... etc..

[LSC97wxnut]

Hard forecast for school superintendents inside 128 tomorrow. Do you burn the day on Monday for what could be just rain, knowing Tuesday appears to becoming a sure snow day.

[dryslot]

Just now, WinterWolf said:

I’ll take my 15” and be very happy!  Thank you GFS.

Somebody is seeing better then 10:1 for a time as well with that CCB.