Winter 2019-2020 Discussion

[Typhoon Tip]

There's also a question of instrumentation and/or measurement standards and techniques there in ...

I'm sure they were diligently intended back whence - that's not the point... But, we're talking about decimal increases in many cases... and decimals can certainly be accounted for in snow fall - particularly, in snow fall at varying temperatures... For that matter, it should be melted equivalency and then denote precipitation in keeping with best empirical method.

Seeing as the precipitation increases have been noted globally ...that does foist a bit of a yellow flag not to be dismissive of the notion - not that anyone is...just be cautious... 

I've heard that snow increase bandied about but I haven't actually read any peer reviewed/accredited metrical sciences on that subject matter...  It certainly more than seems plausibly true just existentially ... but my own experience doesn't stem back to the middle part of last Century either.  We toiled and clawed for 6" snow falls throughout my childhood in the 1980s ...which can certainly be noise.  We had bone chilling cold of the 1970s ... but really not as much snow as one might think - save for the obvious banner years there...  Then the 1990s came along and as the decade aged ... Pez dispensing began... And despite some truly rancid bad snow production seasons, since 2000 ... it's really been staggering how we've actually grown sort of Stockholm Syndrome accustomed to twice that much... or bust.  We get 12" snow out of instability/WAA burst ahead of CCB's that failed to develop/too late because lows are moving to dam fast now more than anything else... Although... 2015 was just an outlier for more reasons than one... we just end up so anomalously deep on the polarward side of the jet storms behaved like a planetary storm event.

Anyway I agree that it's tough question... might come down to, 'sounds like duck; looks like duck; chances are ... it's a duck'  The all over the world thing strikes me -

[ORH_wxman]

2 hours ago, Typhoon Tip said:

There's also a question of instrumentation and/or measurement standards and techniques there in ...

I'm sure they were diligently intended back whence - that's not the point... But, we're talking about decimal increases in many cases... and decimals can certainly be accounted for in snow fall - particularly, in snow fall at varying temperatures... For that matter, it should be melted equivalency and then denote precipitation in keeping with best empirical method.

Seeing as the precipitation increases have been noted globally ...that does foist a bit of a yellow flag not to be dismissive of the notion - not that anyone is...just be cautious... 

I've heard that snow increase bandied about but I haven't actually read any peer reviewed/accredited metrical sciences on that subject matter...  It certainly more than seems plausibly true just existentially ... but my own experience doesn't stem back to the middle part of last Century either.  We toiled and clawed for 6" snow falls throughout my childhood in the 1980s ...which can certainly be noise.  We had bone chilling cold of the 1970s ... but really not as much snow as one might think - save for the obvious banner years there...  Then the 1990s came along and as the decade aged ... Pez dispensing began... And despite some truly rancid bad snow production seasons, since 2000 ... it's really been staggering how we've actually grown sort of Stockholm Syndrome accustomed to twice that much... or bust.  We get 12" snow out of instability/WAA burst ahead of CCB's that failed to develop/too late because lows are moving to dam fast now more than anything else... Although... 2015 was just an outlier for more reasons than one... we just end up so anomalously deep on the polarward side of the jet storms behaved like a planetary storm event.

Anyway I agree that it's tough question... might come down to, 'sounds like duck; looks like duck; chances are ... it's a duck'  The all over the world thing strikes me -

1980s/early 1990s probably skewed some perception too for those of us that remember. They are truly putrid snow years that are unrivaled in the record...that period sticks out like a sore thumb. There were some pretty bad periods between the late 1920s and early 1950s but none of them could match that 1979-1980 though 1991-1992 stretch. 

So while the prolific snow producing storms since 2000 are certainly note-worthy, they are especially glaring when compared against the backdrop of the 1979-1992 period. It's like "let's take the most prolific 15 or so years and compare them against the worst 15 year stretch...I bet that might make people talk"...for our generation, say those born from the 1970s to early 1980s, we had both periods as really our only experience for SNE winter...and they essentially happened back to back save maybe a brief "shoulder period" in the mid to late 1990s.

Its hard to really say what "normal" is too when it comes to New England snow climo. I can spit out the numbers of course...I know them all like the back of my hand....but it's the way we get to those numbers that is the question. We've had so many periods that were seemingly unmatched in the record. The late 1950s through early 1970s produced nary a below average snowfall season in SNE. Esp over the interior...the consistency was incredible. So was the cold. They were much snowier and colder winters than the previous 30 years. 

Now, after a long period of declining-in-frequency KU events from the 1970s through the 1990s, we all of the sudden see the massive reversal and now the winter spits out a 20" KU like Halloween candy being tossed out to trick our treaters. 

Btw, I do agree some of the individual storm numbers are somewhat inflated versus 30+ years ago due to measuring technique, but that only explains a smaller portion of the situation. 

Anyways, everyone is going to have theories and thoughts on the matter, but nothing will be better than another decade of data and then another decade after that to see what happens. I can guarantee none of the literature in the late 1990s and early 2000s saw the snow boon years coming in New England. 

[40/70 Benchmark]

On 8/12/2019 at 7:09 AM, CoastalWx said:

Boy that's a tough question. If an increase of 1C holds 7% more water vapor and we have been increasing 0.15C-ish per decade across the CONUS (give or take here).....I don't know how you can assert that into snowfall. To me it's more at the mercy of hemispheric nuances that are dictating storm track and temps.  Obviously things don't work linearly in nature. In other words, you can't just say an increase in temps by X-amount means an increase in snowfall by Y-amount. To some degree there likely is an element of AGW...but I remain in the camp that our fortunate run is a result of nuances far beyond AGW. 

 

16 hours ago, ORH_wxman said:

Agreed. The increased moisture just is not enough magnitude to explain it. We've had like a 4% increase in WV here since the 1980s. 

There are other factors...and granted, some could still be related to climate change, but perhaps not as directly. 

I think it has helped a bit, but generally agree, which is what I was getting at. The gradient saturation has not impeded large scale winter storms as of yet.

[Typhoon Tip]

On 8/12/2019 at 9:34 PM, ORH_wxman said:

1980s/early 1990s probably skewed some perception too for those of us that remember. They are truly putrid snow years that are unrivaled in the record...that period sticks out like a sore thumb. There were some pretty bad periods between the late 1920s and early 1950s but none of them could match that 1979-1980 though 1991-1992 stretch. 

So while the prolific snow producing storms since 2000 are certainly note-worthy, they are especially glaring when compared against the backdrop of the 1979-1992 period. It's like "let's take the most prolific 15 or so years and compare them against the worst 15 year stretch...I bet that might make people talk"...for our generation, say those born from the 1970s to early 1980s, we had both periods as really our only experience for SNE winter...and they essentially happened back to back save maybe a brief "shoulder period" in the mid to late 1990s.

Its hard to really say what "normal" is too when it comes to New England snow climo. I can spit out the numbers of course...I know them all like the back of my hand....but it's the way we get to those numbers that is the question. We've had so many periods that were seemingly unmatched in the record. The late 1950s through early 1970s produced nary a below average snowfall season in SNE. Esp over the interior...the consistency was incredible. So was the cold. They were much snowier and colder winters than the previous 30 years. 

Now, after a long period of declining-in-frequency KU events from the 1970s through the 1990s, we all of the sudden see the massive reversal and now the winter spits out a 20" KU like Halloween candy being tossed out to trick our treaters. 

Btw, I do agree some of the individual storm numbers are somewhat inflated versus 30+ years ago due to measuring technique, but that only explains a smaller portion of the situation. 

Anyways, everyone is going to have theories and thoughts on the matter, but nothing will be better than another decade of data and then another decade after that to see what happens. I can guarantee none of the literature in the late 1990s and early 2000s saw the snow boon years coming in New England. 

Definitely agreed here ...  Some free thinking over morning joe -

That's why I was emphasizing melted equivalency?   Water content in the snow is - I think - a more meaningful metric.  Considering mass: the mechanical force, regardless of any circumstance of larger-scaled variability ( and part of that variability being the 'elephant GW in the room' ) would need to be greater for more water transport ... because inertia and gravity are fundamental laws of physics that cannot, disputed, hidden or altered by fluff factor    ... By considering the weight of water in bucket, over larger regional scope and scale and temporal considerations... that should be more telling when something "big" might be changing vs not changing the system.  In a dark humor sense ... that's how nature works;  we'll get 120" snow seasons at 22:1 more repeatedly...then, 40" snow seasons at 6:1 ...more repeatedly ( the latter of which can only happen in a warmer, WV rich transporting atmosphere) and because the latter is less physically consequential/inconveniencing ..this quite proficiently hides global warming's pernicious outcome...  because Gaia's fighting back by attacking the world using her GWeapon of mass destruction - it reminds me of turning an oven up to "Clean" - only the temperature is misdirection-of-empirical-results in this metaphor.

Anyway...  so, if we're ( say ) doubling water equivalences over successive seasons ... the equally important question becomes, at what point does a sample set become more substantive in this business? that's a harder question ... 10 years.  20...40...160 ?  I figure Millennial changes are safe. 

We all know that atmospheric shenanigans behaves like faux fractals ... which is to say, not really 'true ' chaos governed. But, there can be periods of time when results do repeat ... then, some form of unknown but real underlying paradigm shift take place - said pattern factors --> results falls apart ... and a new set of results seems to be a better indicator... Until that breaks down.. We see a quasi semblance of this sort of faux patterning in atmospheric variability.

My belief is there are certain regions of the planet where this is more likely to occur - here being one of them.  Just based upon geographical/geological antecedent "fixed" circumstances ...those regions tend to always own the variability a bit more.  The region roughly bounded by the Great Lakes to New England ... upper Mid Atlantic, to SE Canada and the lower Maritime regions is one such region.  This is the convergence point of two main jet structures, and arguably a third: Subtropical; Polar; Arctic (but really just the former two). Upstream forcing from disparate integrals vary these ... then, they tussle against one another for proxy ...here. More so than say ...the West Coast of North America ...where the Ferrel Cell tends to expand and covers their region from "as much" ( albeit intensely consequential when their pattern does flip around...).

Anywhere on the planet where these "unmanned fire-hose" flop regions exist.. tend to own the lion's share of variability. This is critical in my estimation.. .because these 'fractal ' modes of internal variability ... at times even spanning a decade or two ... they can and do mask systematic changes due to climate change. 

I suspect the PNAP base-line N/A pattern ... which features a low amplitude western hump in the isohypses...and a flat open ended trough exiting the eastern limb of the continent - that base-line "canvas" ( if you will..), that alone might tamp down the synergy feed-backs of GW on temperatures ... which by common reasoning ... then might factor into precipitation profiles.  Now .. some astute reader that's successfully gotten this far might go ...wo wo wo, hold on Tex' - we've been above normal... Yeeeah... but not "AS" above normal.. It's not petty to make that distinction.  This is empirically shown that our positive departures are muted relative to other regions of the Globe - where by virtue of their geo - circumstantial ...may synergistically favor them like a Patriots football team. People need to understand that gestalt is true; it is by definition ...non-quantifiable, yet is a very real skewer in this GW stuff ... It is used as leverage by amoral arguments/deniers/ and/or cherry-pickers with other types of agenda in general... But I digress...  

 

 

 

[Typhoon Tip]

On 8/13/2019 at 9:32 AM, 40/70 Benchmark said:

 

I think it has helped a bit, but generally agree, which is what I was getting at. The gradient saturation has not impeded large scale winter storms as of yet.

Not sure how we can make this distinction - albeit ...we are just being conjectural here   But, this is a "poly-contextual" question. 

Firstly, what is meant by "impeded"?    Also, what is meant by "large scale winter storms" for that matter - this latter characterization may be prone to subjectivity ..which I really ..nothing sends me to irate distraction like someone hiding in semantics so let's not go there.  ahaha.  

Seriously, we get winter "events".  Frequency of lesser impacting events is favored in higher gradient.  But that has more to do with storm "organization"/structural mitigation to screaming balanced flow being a negative interference in the physical interplay between larger to smaller scale wave-mechanics.   Simple words ... more storms, nickle and dimers...  with less ability to generate slow moving bombs. Winters that tended to steady diets of 4 to 8" events actually own the top total years - Will?  I dunno ...it's more a question for him.. But I'm pretty sure that our bigger snow years come from buck shot numbers...that than through a biggie to bring it over the top... Yeah, relative to all data sets there are outliers... but honest interpretation -

Another way this textured layering confuses this when trying to reconstruct how GW is effecting large scale circulation -- > storm genesis/snow and so forth...  Just because a storm is sheared ...doesn't mean it won't dump snow prolifically?  Also, although shearing patterns may offer challenges to deeper Norwegian Model low idealized results.., there's likely to be snow falling from other large scale mechanical forcing.  Broad overrunning/isentropic slope events for example, which in fact, we happen to know are favored in gradient rich circulation mediums.

In other words, there's a few ways to get snow and/or in-the-bucket water content elevated.

[40/70 Benchmark]

1 hour ago, Typhoon Tip said:

Not sure how we can make this distinction - albeit ...we are just being conjectural here   But, this is a "poly-contextual" question. 

Firstly, what is meant by "impeded"?    Also, what is meant by "large scale winter storms" for that matter - this latter characterization may be prone to subjectivity ..which I really ..nothing sends me to irate distraction like someone hiding in semantics so let's not go there.  ahaha.  

Seriously, we get winter "events".  Frequency of lesser impacting events is favored in higher gradient.  But that has more to do with storm "organization"/structural mitigation to screaming balanced flow being a negative interference in the physical interplay between larger to smaller scale wave-mechanics.   Simple words ... more storms, nickle and dimers...  with less ability to generate slow moving bombs. Winters that tended to steady diets of 4 to 8" events actually own the top total years - Will?  I dunno ...it's more a question for him.. But I'm pretty sure that our bigger snow years come from buck shot numbers...that than through a biggie to bring it over the top... Yeah, relative to all data sets there are outliers... but honest interpretation -

Another way this textured layering confuses this when trying to reconstruct how GW is effecting large scale circulation -- > storm genesis/snow and so forth...  Just because a storm is sheared ...doesn't mean it won't dump snow prolifically?  Also, although shearing patterns may offer challenges to deeper Norwegian Model low idealized results.., there's likely to be snow falling from other large scale mechanical forcing.  Broad overrunning/isentropic slope events for example, which in fact, we happen to know are favored in gradient rich circulation mediums.

In other words, there's a few ways to get snow and/or in-the-bucket water content elevated.

John, I'm not hiding behind semantcs. We have had an unprecedented frequency of 12"+ snowfalls over the past 25 years. While this is partially attributable to disparate measuring techniques, clearly the gradient saturation has not been a large mitigator. Last season not withstanding, unless you have been in a coma since the mid 90s, it clear these large snowfalls have been predominstely from major coastals, and not overrunning. 

We have not had an issue igniting major coastal cyclogensis as of yet, however no one can definitively say whether this will take place in the future.

[Typhoon Tip]

1 hour ago, 40/70 Benchmark said:

John, I'm not hiding behind semantcs. We have had an unprecedented frequency of 12"+ snowfalls over the past 25 years. While this is partially attributable to disparate measuring techniques, clearly the gradient saturation has not been a large mitigator. Last season not withstanding, unless you have been in a coma since the mid 90s, it clear these large snowfalls have been predominstely from major coastals, and not overrunning. 

We have not had an issue igniting major coastal cyclogensis as of yet, however no one can definitively say whether this will take place in the future.

I didn't exactly say you were - the impetus wasn't accusatory there... just not to engage in that which semantics strains the goal of consensus ( to put in mildly) in the first place - think preemptive/sarcasm for fun. 

Like I said... this is conjecture on both sides -   ...but that means subjectivity.  So taken fwiw -

Unless we provide every snow event since 1990 and somehow qualitatively assess 'how much of those' were from either event profile - which ...there can be cross over -...  I mean holy heck.  We're arguing through our hats. 

But such is the nature of the beast in speculation vs real math and science in anonymity of social media -

... All I know and am confident of, is that over the last two decades...storm trajectories have been speeding up...and, balanced geostrophic wind velocities have also concomitantly risen ...most likely due to the compressive effects of the swelling tropical/subtropical Hadley cell into the Ferrel cell of the mid latitudes...that key region where our storms evolve, which exists between the subtropical latitudes and 60 N.  Endemic to this era has been modeling performances ... tending to over assess cyclogen in mid ranges...only to have to mitigate development - note, mitigation is not black and white stoppage.  I mean that in partial sense... It's gradation -

 

 

 

[powderfreak]

And it’s been widespread too...even back to ALB and BTV in the interior have had a large proportion of their biggest snowfalls ever since 2000.  And they have large POR.  

And not only that, both ALB and BTV have had seasons with multiple top 15 storms in them.  

Even with measuring differences between now and ages ago, to get 10 of 20 highest snowfalls in the past 18 winters at BTV is remarkable when the POR goes back to 1800s.  Even some big QPF events too, like Valentines Day 2007 was BTV’s largest February frozen SWE.

[Typhoon Tip]

1 hour ago, powderfreak said:

And it’s been widespread too...even back to ALB and BTV in the interior have had a large proportion of their biggest snowfalls ever since 2000.  And they have large POR.  

And not only that, both ALB and BTV have had seasons with multiple top 15 storms in them.  

Even with measuring differences between now and ages ago, to get 10 of 20 highest snowfalls in the past 18 winters at BTV is remarkable when the POR goes back to 1800s.  Even some big QPF events too, like Valentines Day 2007 was BTV’s largest February frozen SWE.

yeah... uh.. just for the record - I'm not on either side of that snow debate ...really.

My concerns is the large scale - Globular - circulation changes that are presently being researched as caused by climate change, and the fact that the evidences are massive ... and confidence is high within the greater reputed ambit of NOAA, NCEP and countless other institutional informatica circuitry, that shows those changes are for real, and causally linked to the former. 

That.  needs. to. be. incorporated. into. seasonal. forecasts.

Because... said efforts cannot be based upon the previous statistical packages if the governing circulation that created those statistics in history have changed - that's just logic. Not sure how to get around that and to be stubbornly reliant on methods being left behind by the evolution and the forces of change over time, is tantamount to inane. 

I'm sensing I'm being accidentally railroaded into the snow increase, climate vs noise thing...  - I won't serve as a lightning rod.  I don't give a shit about snow.  The circulation is changed because the subtropical Hadley cell is expanding with a warming world, and it is encroaching on the Ferrel cell region of the mid latitude ( roughly 35 to 60 N) ...and that is expressing as a gradient rich environment.  Gradient directly enforcing faster balance wind field... and that definitely by numerical/physical proxy effects wave mechanics embedded within.  Not debatable... 

I've heard that snow increase bandied about,  and anecdotally/existentially... I will add ... I've personally witnessed the increasing snow stuff since 2000... But that's as far as I'll go into that stuff.  In other words, these may be mutually exclusive... Bigger seasons due to aggregate totals... storm behavior this that or the other thing... More actually falling because there is more WV...   I dunno - 

[powderfreak]

@Typhoon Tip my post had literally nothing to do with your thoughts.  I hadn’t even read your posts to be honest, I just briefly saw something from Ray about larger events occurring recently, and chimed in.  

I should’ve read the whole long winded exchange in here but honestly it wasn’t directed at anyone or meant to “railroad” you.  Just left it there.

[CoastalWx]

John sometimes gets sensitive with this stuff.   

[Typhoon Tip]

24 minutes ago, CoastalWx said:

John sometimes gets sensitive with this stuff.   

Nah. 

I was just using his post for making general point about my position on the snow. 

Probably my fault that he interpreted that as directed at his other stuff

[bristolri_wx]

This is a really interesting discussion on a hot summer's day. 

I wonder if there is any correlation between the above normal SST's of the Gulf Stream about 250 miles to the southeast of us, and the generally observed increase in seasonal snow amounts since the late 90's?  SST's have been consistently running 2-5 degrees celsius above normal in this area since late 1996 according to the SST anomaly maps located here:

https://www.ospo.noaa.gov/Products/ocean/sst/anomaly/

At this point it makes you wonder if it's even an anomaly anymore if it's been running above normal for over 20 years.  I would imagine that the above normal SST's have an influence on cyclone strength and other aspects of our weather year round.  Maybe this could also partially explain why ratters aren't nearly as ratty as they used to be. 

Perhaps just one piece of the puzzle...

Overall I'm inclined to believe that the warming SST's in the Arctic and lesser amounts of polar ice will have a profound effect on our weather, especially in the winter.  Whether it's a short term, or long term pattern shift, our winters seem to be back loaded into February and March more years than not, and I (anecdotally) feel that we have more swings between above normal and below normal temperatures thanks to these kinks and bulges in the jet stream that researchers are starting to feel are caused by the warmer temps up in the Arctic.

[CoastalWx]

1 minute ago, Typhoon Tip said:

Nah. 

I was just using his post for making general point about my position on the snow. 

Probably my fault that he interpreted that as directed at his other stuff

It’s a good topic. Who knows what and how man-kind is messing with all this stuff. We’ve certainly had a fortunate run. 

[ORH_wxman]

5 minutes ago, bristolri_wx said:

This is a really interesting discussion on a hot summer's day. 

I wonder if there is any correlation between the above normal SST's of the Gulf Stream about 250 miles to the southeast of us, and the generally observed increase in seasonal snow amounts since the late 90's?  SST's have been consistently running 2-5 degrees celsius above normal in this area since late 1996 according to the SST anomaly maps located here:

https://www.ospo.noaa.gov/Products/ocean/sst/anomaly/

At this point it makes you wonder if it's even an anomaly anymore if it's been running above normal for over 20 years.  I would imagine that the above normal SST's have an influence on cyclone strength and other aspects of our weather year round.  Maybe this could also partially explain why ratters aren't nearly as ratty as they used to be. 

Perhaps just one piece of the puzzle...

Overall I'm inclined to believe that the warming SST's in the Arctic and lesser amounts of polar ice will have a profound effect on our weather, especially in the winter.  Whether it's a short term, or long term pattern shift, our winters seem to be back loaded into February and March more years than not, and I (anecdotally) feel that we have more swings between above normal and below normal temperatures thanks to these kinks and bulges in the jet stream that researchers are starting to feel are caused by the warmer temps up in the Arctic.

I think the backloaded winters are more of a result to a shift of +PDO/Niño type PAC since 2011 rather than some permanent alteration of the polar jet. Before that, we couldn't buy a blockbuster Feb/Mar for like 7-8 seasons going back to the early 2000s. Instead, we had a lot of front-loaded big Decembers and Januarys in that 2003-2011 time period. I suspect this will shift back again once we have a more Niña/-PDO look again like we did in the late 2000s/early2010s.

You may be right about the increased blockbuster storms though and the Gulf Stream anomaly since 1996 though. I'm not sure how accurate those maps are on a small scale like that, but certainly higher SSTs up against lower anomalies to the north would be a good breeding ground for cyclogenesis. 

[40/70 Benchmark]

8 hours ago, Typhoon Tip said:

yeah... uh.. just for the record - I'm not on either side of that snow debate ...really.

My concerns is the large scale - Globular - circulation changes that are presently being researched as caused by climate change, and the fact that the evidences are massive ... and confidence is high within the greater reputed ambit of NOAA, NCEP and countless other institutional informatica circuitry, that shows those changes are for real, and causally linked to the former. 

That.  needs. to. be. incorporated. into. seasonal. forecasts.

Because... said efforts cannot be based upon the previous statistical packages if the governing circulation that created those statistics in history have changed - that's just logic. Not sure how to get around that and to be stubbornly reliant on methods being left behind by the evolution and the forces of change over time, is tantamount to inane. 

I'm sensing I'm being accidentally railroaded into the snow increase, climate vs noise thing...  - I won't serve as a lightning rod.  I don't give a shit about snow.  The circulation is changed because the subtropical Hadley cell is expanding with a warming world, and it is encroaching on the Ferrel cell region of the mid latitude ( roughly 35 to 60 N) ...and that is expressing as a gradient rich environment.  Gradient directly enforcing faster balance wind field... and that definitely by numerical/physical proxy effects wave mechanics embedded within.  Not debatable... 

I've heard that snow increase bandied about,  and anecdotally/existentially... I will add ... I've personally witnessed the increasing snow stuff since 2000... But that's as far as I'll go into that stuff.  In other words, these may be mutually exclusive... Bigger seasons due to aggregate totals... storm behavior this that or the other thing... More actually falling because there is more WV...   I dunno - 

Yea, I'm not arguing the physics of the idea...more just speculating on the impact in terms of snowfall. I will say that it has been like pulling teeth to get really slow movers the past couple of decades, which maybe the gradient saturation manifesting itself. However I think speed of movement is an overrated determinent of snowfall....its all about dynamics, which are relatively fleeting, anyway...6-9 extra hours of shreded RAD echoes are fairly inconsequential.I think that increased frequency of excessive snowfalls in the face of the gradient saturation is a testament to this.

Additionally, the gradient is also beneficial in terms of east coast snowfall at times in the absence of blocking....goes both ways.

[Typhoon Tip]

8 hours ago, 40/70 Benchmark said:

Yea, I'm not arguing the physics of the idea...more just speculating on the impact in terms of snowfall. I will say that it has been like pulling teeth to get really slow movers the past couple of decades, which maybe the gradient saturation manifesting itself. However I think speed of movement is an overrated determinent of snowfall....its all about dynamics, which are relatively fleeting, anyway...6-9 extra hours of shreded RAD echoes are fairly inconsequential.I think that increased frequency of excessive snowfalls in the face of the gradient saturation is a testament to this.

Additionally, the gradient is also beneficial in terms of east coast snowfall at times in the absence of blocking....goes both ways.

Well...since you put it this way ...I don't disagree ... 

I also think that increased snow fall -- having caved last night and given it more thought -- could very easily be guided by two very certain factors:

1 ... increased frequency of smaller events - aggregation as oppose to 'block-buster' season definers...  

2 ... whether true or not... any system tapping into increase ambient WV associated with a warming world.. would, counter-intuitive to the lay-folk... proficiently rain or snow, both. It's just that yar ...as the world warms... one side of that gets favored eventually.  

These two factors ... however disparate, appear to be converging in the climate modulation since 2000 - fascinating.  

I will add as an after thought ... for those forecasting seasonal characteristics - if it were me I would keep it in mind that this GW -related circulation modulation stuff is accelerating - by that we mean still changing... Probably not for the better for those interested in cryospheric agenda at middle latitudes... The punching N/invasion/swelling of the mean suptropical circulation eddy into the Ferrel latitudes is why we are seeing increased gradient...  

It kinda more than sorta goes like:

  Arctic is warming at a faster rate ...but since it starts at a very low scalar point ... it still imposes deep heights near the northern girdle of the mid latitudes... This then directly imposes upon said ballooning Hadley cell ... flow speeds up... But, with GW still accelerating ( apparently ...) that Hadley cell expansion ... not sure why that would imminently cease to occur.... and in fact ( pure speculation from this point forward...) I almost imagine the tripolar split of the atmosphere ( Polar:Ferrel:Hadley) becoming more and more duple in character over future years ...however long that takes.  Imagine one contiguous subtropical band with more a singular polar jet ... split flows rarefying...  interesting...  

Anyway, supposition aside, ... that's not 2019-2020 

 

[tamarack]

12 hours ago, ORH_wxman said:

I think the backloaded winters are more of a result to a shift of +PDO/Niño type PAC since 2011 rather than some permanent alteration of the polar jet. Before that, we couldn't buy a blockbuster Feb/Mar for like 7-8 seasons going back to the early 2000s. Instead, we had a lot of front-loaded big Decembers and Januarys in that 2003-2011 time period. I suspect this will shift back again once we have a more Niña/-PDO look again like we did in the late 2000s/early2010s.

Snowfall here is almost evenly divided by the Jan-Feb line; it's now 45.0/45.9 but has remained within an inch over the past few winters.  May just be the different location, but that 9-year period noted above was marked by front/back extremes.  Most front-loaded winters here were 05-06, 09-10 and 03-04.  Most back-loaded were 06-07 and 04-05.  Those 4 winters 03-04 thru 06-07 had front-back whiplash.  Another facet is that, looking only at winters with at least 60% front or back, the front-loaded were poor - 81% of average snowfall with 5 of 6 BN (14-15 the exception), while the back-loaders averaged 118% of average and all 4 were AN.  (The 11 other winters averaged 104% of average - those front-loaded ones dragged the average down.)

[RUNNAWAYICEBERG]

This is an oldie but goodie:

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2012GL051000

[ORH_wxman]

10 minutes ago, RUNNAWAYICEBERG said:

This is an oldie but goodie:

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2012GL051000

That paper basically argues the opposite of tip's gradient "fast flow" theme. Kind of reinforces my statement earlier how there is a bit of "flavor of the month" syndrome in the literature. That paper was published right after the epic blocking of 2009-2011 where we had slow moving bombs. 

[Typhoon Tip]

.. Amplitude in the AA context imposes colder delivery to middle latitudes...which concomitantly slopes the heights ...faster wind speed results.   Again... the Arctic is warming faster than the mid and lower latitude troposphere's ( do to various "synergistic" feedbacks and so forth...), but... it is still generating differentiable cold heights in the autumn and winter, and still sufficiently deep compared to the ballooning Hadely cell to create more gradient. 

They're not talking about geostrophic wind saturation in this article - they are talking about the large scale wave features these winds travel around.   These features are a different beast than the flow along their gradients.  When the gradient speeds up south ..this inegrates a weakening of the annular mode of the Arctic...draws/redraws the polar jet S where the gradient is larger ... this causes slowing of the zonal wind component at higher latitudes - check... But that means the gradient is intense along that southerly displacing polar jet and the wind...fast. 

Also .. for me, if anything... it makes sense that faster flow may "lock" patterns, as the forcing must be large and therefore "immovable" ( relatively..)  and cause R-wave translation/morphology to slow.. because faster wind speeds intuitively would tend to dampen permutation forcing.  

[CoastalWx]

Euro seasonal looks to have a decent Pacific regarding ridging out west, and especially NW Canada and AK. Verbatim it has a strong signal for a +NAO. We'll see if/how that changes going forward. 

[ORH_wxman]

6 minutes ago, CoastalWx said:

Euro seasonal looks to have a decent Pacific regarding ridging out west, and especially NW Canada and AK. Verbatim it has a strong signal for a +NAO. We'll see if/how that changes going forward. 

Our big blocking NAO from this warm season disappears faster than a hair follicle on Kevin's head as soon as October/November swing around.

[dryslot]

If the PAC is right, We will be alright, The -NAO has been pretty much MIA over the last few winter seasons and we have done ok.

[ORH_wxman]

1 minute ago, dryslot said:

If the PAC is right, We will be alright, The -NAO has been pretty much MIA over the last few winter seasons.

We haven't had a full DJFM season average a -NAO since 2012-2013. 2017-2018 was the closest we came on the strength of a big -NAO March that season. But it still finished slightly positive.

In fact, here's an amazing stat.....March 2018 is the only month out of any DJFM cold season that has averaged a -NAO since March 2013. January 2016 was just north of neutral as the closest runner up. January 2017 was also close (it actually averaged slightly negative on the Hurrell SLP method, but slightly positive on the Z500 CPC method).

 

But that is pretty amazing. Out of the past 24 winter months, we could only get one of them to be decidedly negative on the NAO.

[Typhoon Tip]

23 minutes ago, ORH_wxman said:

Our big blocking NAO from this warm season disappears faster than a hair follicle on Kevin's head as soon as October/November swing around.

It's probably more subtle than idealy coherent ... buuut, that seems to be a recurrent theme in recent years...  But all's not lost? 

Because what happens - in deference to Scott's Euro stuff... - is that the NE Pac lends to more -EPO - like perturbations.   We did remarkably well with winter expression in the rough NP-Lakes-SE Can/NE region with stretched L/W down wind of cold loading from that source...  It'll be interesting if replay similar tapes. 

The other aspect is -NAO ... are these biasing over the western vs eastern limb -

[ORH_wxman]

5 minutes ago, Typhoon Tip said:

It's probably more subtle than idealy coherent ... buuut, that seems to be a recurrent theme in recent years...  But all's not lost? 

Because what happens - in deference to Scott's Euro stuff... - is that the NE Pac lends to more -EPO - like perturbations.   We did remarkably well with winter expression in the rough NP-Lakes-SE Can/NE region with stretched L/W down wind of cold loading from that source...  It'll be interesting if replay similar tapes. 

The other aspect is -NAO ... are these biasing over the western vs eastern limb -

Oh yeah...I wasn't implying that we're screwed because of it. Just a few short winters ago, we had our "Labrador visits Boston Harbor" storyline complete with sea ice that didn't melt until after the spring equinox and snow cover draping the buildings like "Day After Tomorrow" footage.

And hell, even since that winter, we've had some pretty good stretches despite the +NAO.

 

But I was mostly rolling my eyes at the "NAO flips positive as soon as summer is over" theme that has been present the past few years. At some point, it would be nice not to have to rely on the EPO/PNA region to bail us out as winter enthusiasts....even though it has bailed us out quite often recently.

[dryslot]

2 minutes ago, ORH_wxman said:

We haven't had a full DJFM season average a -NAO since 2012-2013. 2017-2018 was the closest we came on the strength of a big -NAO March that season. But it still finished slightly positive.

In fact, here's an amazing stat.....March 2018 is the only month out of any DJFM cold season that has averaged a -NAO since March 2013. January 2016 was just north of neutral as the closest runner up. January 2017 was also close (it actually averaged slightly negative on the Hurrell SLP method, but slightly positive on the Z500 CPC method).

 

But that is pretty amazing. Out of the past 24 winter months, we could only get one of them to be decidedly negative on the NAO.

Yeah, That is pretty amazing really we have gone this long without more blocking in that region over a longer DJFM, Getting big coastal systems for snow has been hurt by it too, You know how i am as far as the -NAO goes, We do need it to some extent definitely the further south you go, For here, Its just doesn't need to be at extreme levels or it makes it tough for systems to reach this lat.

[Typhoon Tip]

I almost wonder... hmm..   purely speculation but could the changes in the overall circulation of the N.Hemispheric winter that's been noted over the last two decade be partially causal in that... 

[sebastiaan1973]

16 hours ago, RUNNAWAYICEBERG said:

This is an oldie but goodie:

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2012GL051000

http://www.nature.com/articles/s41558-019-0551-4.epdf?author_access_token=lev7cCLvJaqZgqEL2fkrCtRgN0jAjWel9jnR3ZoTv0OkPw7OWz-ctumf1Sllaa-sNqBW8kixcwl-ojSoyKUmUfvHbXmZ3llXRmZN-HO_pmKRWEHLwCuZqZkuv4bolog-ehQV4R4jg8i93P7ntZX4_w%3D%3D

Observations show that reduced regional sea-ice cover is coincident with cold mid-latitude winters on interannual timescales.

However, it remains unclear whether these observed links are causal, and model experiments suggest that they might not be.

Here we apply two independent approaches to infer causality from observations and climate models and to reconcile these

sources of data. Models capture the observed correlations between reduced sea ice and cold mid-latitude winters, but only

when reduced sea ice coincides with anomalous heat transfer from the atmosphere to the ocean, implying that the atmosphere

is driving the loss. Causal inference from the physics-based approach is corroborated by a lead–lag analysis, showing that

circulation-driven temperature anomalies precede, but do not follow, reduced sea ice. Furthermore, no mid-latitude cooling is

found in modelling experiments with imposed future sea-ice loss. Our results show robust support for anomalous atmospheric

circulation simultaneously driving cold mid-latitude winters and mild Arctic conditions, and reduced sea ice having a minimal

influence on severe mid-latitude winters.