Yellow alert! Archembault, Yellow alert: ~ November 29 thru December 7

[Typhoon Tip]

Caveat emptor:  this does not discuss precipitation types, nor much of any details regarding any plausible events that transpire during that distant time frame, just that there are cues in the tools that may be suggesting an important event.

 

To paraphrase, there are some classic teleconnector modal changes (changes in the indexes..) that have been modeled to occur for many days now, centered on that general period of time. Moreover, they have scientific bases for preceding or occurring in tandem with 'synoptic scaled corrective precipitation events.'

 

That's just fancy talk for ... when a given region enjoys an on-going temperature and moisture pattern, in order to change those thermodynamic conditions, requires (usually) unsettled weather. The teleconnectors moving in certain directions, can be correlated to those sorts of corrective events.

 

 

"...When considered with the study of Archambault et al. (2008), which found no clear statistical relationships between NAO and PNA regimes and the frequency of major NE precipitation events, or between NAO regimes and cool-season NE precipitation anomalies, the present study suggests that NAO and PNA regime transitions may be more strongly related to cool-season NE precipitation than are NAO and PNA regimes...."

 

 c/o: "Relationships between Large-Scale Regime Transitions and Major Cool-Season Precipitation Events in the Northeastern United States";

 HEATHER M. ARCHAMBAULT, DANIEL KEYSER, AND LANCE F. BOSART

 

 

For more detailed reading, go here: http://www.atmos.albany.edu/student/heathera/papers/Archambault_et_al_2010.pdf

 

But some of it is pretty lofty in prose and does go into some mathematical depth; however, the paragraph above is key conceptually to the discussion at hand, most importantly the bold sections.

 

Very clear indication of a regime transition, is being forecast by the CDC re the PNA and NAO indexes.  

 

 

  

Granted, the EPO is not part of H.A. science, but ... as a Met, I can tell you it is not harming her findings!   That EPO offers a cold loading source, which can only positive augment ambient baroclinicity, as it will help to establish continental gradient N-S, such that as these index modes are changing (indicating larger mass fields on the move) this will natively improve cyclogenesis parameters overall.  

 

 

It's a lot of work to demo 'why' that period of time may present a midland event; it could also produce multiples to completely furnish the correction, or perhaps a singular, larger event... To early to tell. But this is all teleconnector convergence on eastern N/A, and I don't believe that much mass-modal change can take place without SOMEthing interesting being there during the title's time frame.  Whatever being may begin to material more frequently as consensus does so as well, as time goes by. 

 

Here is the PNA provided by CPC below, also indicating a reasonably well agreed upon rise in the index spanning the next two weeks.  

 

 

It is my personal belief (non-tested so supposition) that the CPC may carry more usefulness during the cold season, due to the fact that it utilizes geopotential heights in it EOFs; contrasting, the CDC uses low-level max flux (wind) anomalies for theirs.  It may be okay in a sense that both agree in the rise, therein - 

[weathafella]

Well John, I think you are reminding us.

Don't eat yellow snow!

[40/70 Benchmark]

Shocked there wasn't  a bit more activity in here after the EURO run...

[Typhoon Tip]

Yeah it's interesting that the models (sans the GGEM) coalesced so quickly around a DEC 2 -ish event. 

 

Can't say I honestly visualized any such significant event being delivered quite the same way as that: a split-flow ejected bowling ball. That almost looks spring like.  Anyway, ... I suppose in some spatial sense of things it does have similarity.  During that time, we do see more ridging in the west through the dailies.

 

One thing I don't like about that evolution is that heights over Florida remain so elevated throughout.  As is, any such events would have to get squeezed thru a pretty narrow latitude or else there is a shear risk.  

 

A kind of 'rule of thumb' I've noticed in the past: heights and balanced wind flow over MIA can't be too crazy. Talking relative strengths of course. But, heights higher than 582 DM and balanced geostrophic wind velocities > 30 or 35 kts, in all is a detriment to S/W passing through the OV/TV.

 

The reason has to do with shear (sparing a gloss-eyed explanation involving vector calculus).  I like to refer to this as "compressability" of the flow.  500mb(Weak gradient+light wind) = higher compressability 

 

If one needs a deeper explanation ... think of it this way:  if the winds prior to an arriving jet streak (wind max) are blowing at a balanced 70 kts, and the arriving jet streak's wind max is only 80 kts, straight up arithmetic tells us there is only 10 kts of differential speed.  Well, is 10 kts enough to trigger upward vertical motion --> warm conveyor influw jets, strengthening baroclinic zones...etc?   Perhaps a little, but any ensuing low pressure genesis is weak. Contrasting, if the flow is laissez faire 15 kts, and a 70 kts jet streak cuts over that, the differential is very large... 60kts ...  Now we are talking a substantially larger amount of forcing.  Omega goes nutty, warm inflow is instantiated as a result, curl then induces backside NVA, and your in business.  

 

The rest is complex physics in how the thermodynamics of rising pseudo-adiabatic releasing of latent heat causes the core of the low to deepen a lot, which is why you often see a 540 dm trough surfaces drop to 528 when the whole of thing goes through this whole process. 

 

But anyway, lets get some solid continuity for the event in question first.  The heights/wind rule of thumb isn't a deal breaker, either, it's more along the lines of scaling hindrances...heh.  I think the 2005, Dec 10 meso-beta scaled bomb was an example of rarer wave strength riding over top high-ish SE heights.   Contrasting, the very large 2001 March deep layer gyre that was supposed to bring DCA/BOS to their dystopian cryospheric knees, came down, encountered that height wall down there (that wasn't readily noticeable/discussed by Mets mind you) and a kind of 'skipping off a pond' such that it hooked back around later a pummeled areas much farther N than expected.  That latter hooking back into central NE was because initially, despite all that power, it was not differentiating on the flow early enough in the whole-scale life-cycle of events.   Good storm, but unfortunately created a lot blow-back kerfuffle against the Met community, not rivaled in embarrassment since the big Euro bust in NYC recently.  haha, the lovable deviant inside of me chuckled internally when seeing the mayor of the city on the T.V. warning bilblical armeggeddon in split screen while bustling thoroughfares on the other image dinned in blithe...  oh man.  

 

I suppose it's a good thing that storm at least pummeled us..

 

Anyway, I think Scott was saying this earlier in the fall that this year could feature a lot of this split flow antic.  The more I think about that, the more I like that.  With having the NP multi-d looking AA not necessarily on the same page with the ENSO - interesting. 

 

One thing I didn't add: the recurving typhoon in the Pacific may also add some impetus to -EPO at some point, too. 

[Damage In Tolland]

Only a 1024 high. That isn't going to cut it for the coast with those torched SST's

[Ginx snewx]

Shocked there wasn't a bit more activity in here after the EURO run...

talked about in both other threads, fantasy territory for now could disappear at 12

[Typhoon Tip]

talked about in both other threads, fantasy territory for now could disappear at 12

 

Point being ? 

 

You are implying what - since it was mentioned in other threads, this one is redundant and unnecessary ??

 

Perhaps, but I don't spend a lot of time on this interface as a primary social outlet, so I am not always aware of all contributions. Having said that, I doubt those 'talked about in both other threads' reasons to debunk the value of this effort, nearly took the introspective effort as this.  I'm explaining the why said time frame probably will NOT disappear on the 12z; moreover, I made this thread prior to 00z runs - if that is any help.  

 

So sorry if everyone already knew this stuff - 

[ORH_wxman]

Point being ? 

 

You are implying what - since it was mentioned in other threads, this one is redundant and unnecessary ??

 

Perhaps, but I don't spend a lot of time on this interface as a primary social outlet, so I am not always aware of all contributions. Having said that, I doubt those 'talked about in both other threads' reasons to debunk the value of this effort, nearly took the introspective effort as this.  I'm explaining the why said time frame probably will NOT disappear on the 12z; moreover, I made this thread prior to 00z runs - if that is any help.  

 

So sorry if everyone already knew this stuff - 

 

 

No, I think he meant it was mentioned in the other thread because it was a 200 hour OP solution...kind of a waste to talk about it in here, since it was so likely to change next run....or just that 200 hour OP runs don't mean much of anything in general.

 

I'd probably talk more about ensembles in here at this range as to be more relevant to the larger scale discussion.

[40/70 Benchmark]

No, I think he meant it was mentioned in the other thread because it was a 200 hour OP solution...kind of a waste to talk about it in here, since it was so likely to change next run....or just that 200 hour OP runs don't mean much of anything in general.

 

I'd probably talk more about ensembles in here at this range as to be more relevant to the larger scale discussion.

Well, its either this, or QBO/ENSO/temp talk.

 

I think we can focus on this while being conscious of the fact that there still remains a very extended lead.

[Typhoon Tip]

No, I think he meant it was mentioned in the other thread because it was a 200 hour OP solution...kind of a waste to talk about it in here, since it was so likely to change next run....or just that 200 hour OP runs don't mean much of anything in general.

 

I'd probably talk more about ensembles in here at this range as to be more relevant to the larger scale discussion.

 

 

Okay, well .. the entire chain or reasoning for what started this is/was derived from both subtle and gross observations of the teleconnectors, which are entirely based upon the ensembles

[40/70 Benchmark]

Okay, well .. the entire chain or reasoning for what started this is/was derived from both subtle and gross observations of the teleconnectors, which are entirely based upon the ensembles

I think he just meant not to focus on any single, deterministic operational solution.

[Ginx snewx]

Point being ?

You are implying what - since it was mentioned in other threads, this one is redundant and unnecessary ??

Perhaps, but I don't spend a lot of time on this interface as a primary social outlet, so I am not always aware of all contributions. Having said that, I doubt those 'talked about in both other threads' reasons to debunk the value of this effort, nearly took the introspective effort as this. I'm explaining the why said time frame probably will NOT disappear on the 12z; moreover, I made this thread prior to 00z runs - if that is any help.

So sorry if everyone already knew this stuff -

dude get a large grip on yourself. I responded to Ray not you. Oh boy

[40/70 Benchmark]

dude get a large grip on yourself. I responded to Ray not you. Oh boy

I saw you had made mention of the 00z EURO, but given the boring malaise in which we currently reside, I'm just surprised it wasn't discussed at greater length.

I guess people actually work a bit

[Typhoon Tip]

dude get a large grip on yourself. I responded to Ray not you. Oh boy

 

I can't, I'm too obese now - ha! 

 

You come of as bit subversive at times, in all honesty.  If you meant something else, you need to say it THAT way. 

 

Ray asks, 'I'm surprised not more attention'

 

You responded to him, 'because it was already covered in another thread'

 

You're response comes off as eroding the value of the thread at hand; yes, to anyone sentient, that could and probably would be construed that way.  You may not have intended that to be the case, but Ray was wondering why this thread isn't getting attention, and your response didn't offer any other explanation.  

[Zeus]

SET CONDITION ALPO

[Typhoon Tip]

Man, the 12z GFS oper. looks like a great ice storm!  

 

Nice fresh polar high N, with CAD sig in the llv PP suggesting intense ageostrophic flow there up underneath pig mid level moisture transport and support UVM inducing kinematics... 

 

Yuuuummy!  

 

although, hmmm.  I don't like ice storms.  heh, forgetting that.  I mean, their fantastic and all .. untill you're standing their in the dark and re-embarking on that lesson plan that teaches us that without electricity, basically everything in our sentient awareness of reality requires it.  

 

Anyway, this is like hours of moderate ZR

 

 

Granted there are 2-meter type products out there that may not actualize an icing scenario .. .but, part of our charge as Mets is synoptic recognition.  That there looks like a smokin' gun for turn trees in to closed umbrellas. 

[Ginx snewx]

I can't, I'm too obese now - ha!

You come of as bit subversive at times, in all honesty. If you meant something else, you need to say it THAT way.

Ray asks, 'I'm surprised not more attention'

You responded to him, 'because it was already covered in another thread'

You're response comes off as eroding the value of the thread at hand; yes, to anyone sentient, that could and probably would be construed that way. You may not have intended that to be the case, but Ray was wondering why this thread isn't getting attention, and your response didn't offer any other explanation.

lol wut, anyways I made mention of the door opening for a Miller A last week. Good thread

[Damage In Tolland]

Icestorm? Lol

[dryslot]

White Ice

[40/70 Benchmark]

Non event here if that is where this is going.

 

32.00000000000001 R

 

Oh well.

[40/70 Benchmark]

Is there any front end action?

[Ginx snewx]

Is there any front end action?

no lol

[dryslot]

To warm

[Damage In Tolland]

This is either a rain or snow scenario. Not an icestorm. There's no low level cold air. Setup favors far NNE.

[Ginx snewx]

This is either a rain or snow scenario. Not an icestorm. There's no low level cold air. Setup favors far NNE.

setup doesn't favor anything, its way too far out

[Damage In Tolland]

With no strong high and blocking it favors a storm coming north and dropping snow over far NNE

[Baroclinic Zone]

With no strong high and blocking it favors a storm coming north and dropping snow over far NNE

Why are you so convinced there will even be a storm?

[Damage In Tolland]

Why are you so convinced there will even be a storm?

Why are you so convinced there won't be a storm?

[40/70 Benchmark]

Why are you so convinced there will even be a storm?

Teleconnector convergence.

 

Something will go down....

[Baroclinic Zone]

Why are you so convinced there won't be a storm?

I'm not convinced of anything.  You're already calling for a rainer here and a snowstorm for NNE.  That's a bit premature don't you think?  I see the teleconnectors support a phase change system.  Whether or not that pans out remains to be seen.  If there is a storm it could cut west, could cut east, could go over us.  There is nothing to support any particular track of a possible storm.