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December Pattern Disco- 2013


Damage In Tolland

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Still looks to be a shallow cool fropa leading into Friday... Euro is tardy and perhaps the GFS a tad too fast -- taking the blend on timing. Cold is not in any hurry to rush in.. The GFS persists with it's notion of two or three waves, each progressively colder in p-type, beginning Saturday through next Mon/Tue. Higher res models only so-so agree but do have events. The GFS would imply a chilly rain on Friday, lulls, then later Sat there might be icing...then, the more important wave, which has been on the last 5 cycles really, develops a coastal that appears would be snow. GGEM has two waves...one transitioning into a chilly rain... then a mix bag, weak Miller B deal around D6/7. Euro's not out yet

Icestorm!
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Still looks to be a shallow cool fropa leading into Friday... Euro is tardy and perhaps the GFS a tad too fast -- taking the blend on timing.  Cold is not in any hurry to rush in.. The GFS persists with it's notion of two or three waves, each progressively colder in p-type, beginning Saturday through next Mon/Tue.   Higher res models only so-so agree but do have events. The GFS would imply a chilly rain on Friday, lulls, then later Sat there might be icing...then, the more important wave, which has been on the last 5 cycles really, develops a coastal that appears would be snow.  GGEM has two waves...one transitioning into a chilly rain... then a mix bag, weak Miller B deal around D6/7.   Euro's not out yet

yeah i think that's important to note as most guidance really doesn't have a strong push of cold behind the first front. so even if it comes through friday morning...the real chill is way west of the boundary - at least as currently modeled. i could see where the surface to 9h layer maybe cools enough for some icing or sleet. 

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Seems we've been reading "day 7-14" for 5 days, though...  Should be days 2- 9 by now.

 

Also, can someone explain to me what in the hell a "gradient pattern" is... I can find no formal definition in the AMS Glossary, and cannot recall any formal analysis via 3 levels of synoptic Meteorology while in college.  Highly suspect it is an expression evolved on the weather enthusiast, blogosphere, as it started getting bandied about a few years ago, but I never fully understand or even visualized what it is...    I also don't really like "southwest flow event", to be honest.   Are these facets tested scientifically ?

it's made up nonsense. every winter has a snowfall gradient
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Icestorm!

 

I don't know if I'd go that far  :lol:     But yeah... thing is, this -EPO/+NAO is an ice storm canvas;  problem has been in the artist -- almost call it bad luck.  Yesterday had no business being 32.4 with .3" of liquid.  If you are ice-enthusiast, you just had your keester serviced.

 

Just because we are prone, doesn't mean events will come together.   However, this week-ending notion of wedging the lead polar boundary under the compressed 500mb flow (between vestigial Bahama ridge and the trough pressing east out of the Rockies) most certainly does enhance overrunning scenario(s).    But it also looks too progressive for an "ice storm."  They do come in different flavors.  You can have your operation shock and awe storms like 2008, that do all their damage in 15 or so hours. Then you have your 4-day deals that drape a boundary perfectly with refreshing ageostrophic polar high producing cold magnate to keep you 30.2F with steady zr.  These latter are actually more efficient accretions.    I don't really see (so far) either form... More like the middle wave in the procession being a light icer...

 

By the way the stuff on Friday that blossoms from the TV to SNE appears very ANA in structure

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Gradient pattern -  Cold N/ Warm S.  Typically a zonal flow(W-E) with little to no amplification.  Systems tap moisture from the Gulf/Atlantic and ride up over the cold dropping everything from sleet, snow, rain, freezing rain.

 

There pop that into your weather dictionary.

 

Thats what I think of a "gradient pattern". Snowfall distribution is more N-S and more dependent on latitude due to warming mid level temps. 

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it's made up nonsense. every winter has a snowfall gradient

 

 

Well ... I don't have a problem with the expression existing, per se, just for the life of me someone f explain it so it has some kind of clear, accountable, tangible meaning!   

 

Someone just posted "cold north, warm south"    ...ah, no.  Not acceptable.  It's always cooler north of a given latitude, save for some transient very brief synoptic event that inverts the thermal fields -- like an occluded low/seclusion or what-have-you... But we're talking "patterns," not events.

 

It may be a psycho-babble bargaining thing, too... I've sensed that on these emotionally charged weather forums over the years.  When folks' allow this crap to guide their feelings, there is kind of a 4 (or is it 5?) stages of death recovery phenomenon -- for lack of better expression.  The bargaining phase in this case is making up expressions that denies the truth that it's not snowing... hahaha.   Kind of funny actually.. 

 

But that stuff aside, there may very well be some value to the expression;  I just don't have enough of a visualization on what people mean to identify it in any given product analysis and that's annoying. 

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Thats what I think of a "gradient pattern". Snowfall distribution is more N-S and more dependent on latitude due to warming mid level temps. 

 

 

Again ... just to be scientifically precise... I don't see how this statement is any different than climatology.  

 

I guess if it snows in a big TV to lower MA event that leaves the OV-NE regions dry and out of the event entirely, that's "NOT" a gradient pattern? 

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Again ... just to be scientifically precise... I don't see how this statement is any different than climatology.  

 

I guess if it snows in a big TV to lower MA event that leaves the OV-NE regions dry and out of the event entirely, that's "NOT" a gradient pattern? 

 

It's an enhanced thermal gradient and snowfall distribution from S-SW to N-NE.  The kind that gave NYC 12" and southern NH 100" during 2007-2008. 

 

This pattern next week favors that, but beyond it may go to the crapper or shift farther north towards Canada as Pacific flow increases. The mid month period is certainly not a lock and will probably take another week to sort out since slight nuances could allow the cold to ooze south.

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are you being serious? 

 

honest question: do folks not really know what is being implied when we say gradient pattern?

 

 

I think we mention things like "well below average cold in Canada" and "southeast ridge" about 90% of the time when we refer to a gradient pattern.

 

Terms like HECS, MECS, and 50/50 low are "made up terms" too not in the AMS glossary. DT made them up years ago but its pretty obvious we know what they mean.

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Again ... just to be scientifically precise... I don't see how this statement is any different than climatology.

I guess if it snows in a big TV to lower MA event that leaves the OV-NE regions dry and out of the event entirely, that's "NOT" a gradient pattern?

There is always a gradient somewhere. That's the problem with that phrase. Maybe a tighter than normal gradient? But if it's +8C over BOS, but -4C over ALB during a storm at H85...that's also a gradient, no?
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First of all... the fact that it is not even recognized in the science formally, and officiated, speaks volumes... 

 

Secondly, that said ... there really is no reason why the expression cannot be validated. So, having said that, the question is "weather" that means snowfall distribution, in which case it is a land/air ...more so than air, pattern.   That would carry some interesting implications, because as we know, snow on the ground certainly does play a role in modifying the temperatures both in and outside (fair weather) events. 

 

From what I am gathering here, a possible definition for gradient pattern could be, anytime the distribution of snow cover is parallel to the flow.   Interesting. 

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The whole gradient pattern refers to a greater gradient than normal. Obviously there is always a thermal gradient.

It's like when we talk about the PAC jet...there's always a jet out there, but when we say it's taking over the pattern we just mean it's stronger than normal.

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It's an enhanced thermal gradient and snowfall distribution from S-SW to N-NE. The kind that gave NYC 12" and southern NH 100" during 2007-2008.

Oh it's that direction? I always thought it was the gradient from SE to NW. Or is it more of a south-north thing?

I honestly never knew there was a set circumstance...just thought it was wherever the baroclinic zone is located, with a tighter than normal gradient.

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The whole gradient pattern refers to a greater gradient than normal. Obviously there is always a thermal gradient.

It's like when we talk about the PAC jet...there's always a jet out there, but when we say it's taking over the pattern we just mean it's stronger than normal.

Yeah ok, that's what I thought. Tighter than normal gradient, no matter where?

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I think we mention things like "well below average cold in Canada" and "southeast ridge" about 90% of the time when we refer to a gradient pattern.

 

Terms like HECS, MECS, and 50/50 low are "made up terms" too not in the AMS glossary. DT made them up years ago but its pretty obvious we know what they mean.

 

Ooh ooh, I like that definition too!   This one is more purely air.   

 

I don't know if folks can recall but back in the days of Eastern I used to hammer, ad nauseam, the notion that just because we may observe a deep trough anchored in the OV, that doesn't necessarily mean a stormy pattern for us.   Particularly when the heights over Florida are elevated.  Because that means the balanced geostrophic wind is howling along so fast that S/W can't operate on the flow... they get lost and sheared in pattern when the gradient is too much.  

 

Nice, seems we are converging on a real definition that works.  I like this one of your better because it fits in which my 582DM heights over MIA, rule of thumb.

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Oh it's that direction? I always thought it was the gradient from SE to NW. Or is it more of a south-north thing?

I honestly never knew there was a set circumstance...just thought it was wherever the baroclinic zone is located, with a tighter than normal gradient.

usually we have the low level ageo flow from the NE with the sfc high to our N-NE so it tends to be a SW-NE gradient in snowfall. Hence why NE MA does well with these setups while west of the berks/greens can torch.
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Yeah ok, that's what I thought. Tighter than normal gradient, no matter where?

 

 

Yeah, I like it too -- as I was just telling Will...

 

Btw, in case anyone was thinking ... the purpose was not argumentative but purely educational for me.  I just have a formal education in Meteorology that never included any such definition or phrase for that matter.  But I really like the positive anomaly gradient method, because as I was just telling Will, it is something I noted years and years ago re cyclogen limitations in the background flow/medium. 

 

I would extend a rather obvious supposition;  gradient patterns are not very conducive to larger events; though that does not mean bigger SD cannot take place. It's just that the flow would by physics be too fast to allow much other than open waves. 

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usually we have the low level ageo flow from the NE with the sfc high to our N-NE so it tends to be a SW-NE gradient in snowfall. Hence why NE MA does well with these setups while west of the berks/greens can torch.

Ahhh, I was always just thinking it meant a tighter than normal gradient but could be applied anytime...ie GC getting crushed at 20F while it's 45F and raining along I95.

Or a situation like this weekend with a polar boundary and tightly packed H85 gradient, with snow NW and rain SE, but tighter than normal as waves ride the boundary.

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I think we mention things like "well below average cold in Canada" and "southeast ridge" about 90% of the time when we refer to a gradient pattern.

 

Terms like HECS, MECS, and 50/50 low are "made up terms" too not in the AMS glossary. DT made them up years ago but its pretty obvious we know what they mean.

exactly. i didn't realize folks were confused on what was implied. our mistake i guess. obviously there's always a gradient - that's weather. LOL. 

 

i think if you wanted to take it a step further, you could say the persistence of the SE ridge (general -pna type of set-up) in a gradient pattern will support the mid-level energy passing SW to NE through the tennessee or ohio river valley regions...likely initially giving you a surface reflection heading W of our longitude. but the existence of the anomalous cold in canada forces triple point/secondary etc over or south of our latitude. 

 

as i see it, the good gradient pattern doesn't yield a cutter...an inland runner...or a traditional miller a coastal. 

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