October 2016 Observations and Model Discussion for the Pacific Northwest

[Front Ranger]

This doesn't make any sense. The Siberian High is a self-sustaining, semi-permanent feature that creates a positive feedback loop during the cold season, building its own store of cold air.

Yes, and it turned cold there early this year, while the Arctic was very warm.

 

But it's not just Siberia, it's much of Asia. Not every year has the snow expansion in Asia in October this year had.

[wx_statman]

And the fact top tier mid winter blasts have been hammering the Eastern US.  I once again emphasize the lack of mid winter cold has also effected areas of the West that get cold much more easily than the Western Lowlands.  The fault is the 500mb pattern during the heart of the winter.

 

You don't think the evolving 500mb patterns and the warming Arctic are related?

[wx_statman]

The northern Rockies have also had trouble with mid winter cold lately.  That's why I say the terrain here is not the culprit.

 

This is a simplistic statement. You're ignoring the issues here. 

[wx_statman]

Could be. But you said "my argument falls apart" - it's not my argument. I'm asking Jesse or anyone else for proof that the warming Arctic has caused the lack of major mid winter cold.

 

I definitely know that certain blocking patterns are needed to get the PNW cold, and I know those have been lacking in mid winter.

 

This comes off as anti-scientific. If everything in nature could be proven so easily and delivered on an online message forum, we wouldn't have any scientists! 

[Front Ranger]

Nobody has made that claim. Rather, a warmer Arctic has been sited as one of the contributing factors. And why wouldn't it be? Warmer source airmass = warmer result at lower latitudes.

 

As you keep saying, nature isn't that simple. It may be a factor, but until someone can show me something solid that proves a warmer Arctic is preventing cold air masses from reaching the PNW in mid winter (for some reason), I'll stick with what I know: it comes down to getting the right blocking pattern. When you've gotten the right blocking pattern, the warm Arctic has not prevented impressive cold like 2010, 2011, and 2013.

 

Not that hard to follow.

[Front Ranger]

This comes off as anti-scientific. If everything in nature could be proven so easily and delivered on an online message forum, we wouldn't have any scientists!

Actually, I'm questioning statements because I'm not seeing much science behind them. Asking for evidence is not unscientific.

[Deweydog]

As you keep saying, nature isn't that simple. It may be a factor, but until someone can show me something solid that proves a warmer Arctic is preventing cold air masses from reaching the PNW in mid winter (for some reason), I'll stick with what I know: it comes down to getting the right blocking pattern. When you've gotten the right blocking pattern, the warm Arctic has not prevented impressive cold like 2010, 2011, and 2013.

 

Not that hard to follow.

I think your mid-winter equivalency test you've applied to those events is just as shaky as any attempt to "prove" a meaningful connection to Arctic bath water.

[Front Ranger]

I think your mid-winter equivalency test you've applied to those events is just as shaky as any attempt to "prove" a meaningful connection to Arctic bath water.

It's not an equivalency test. The point is that if it's all about the source region being warmer, why are we still seeing top tier early season events? Shouldn't those air masses also be warmer, especially since the greatest amount of Arctic warming has occurred in fall?

 

It just doesn't pass the logic test.

[Deweydog]

It's not an equivalency test. The point is that if it's all about the source region being warmer, why are we still seeing top tier early season events? Especially since the greatest amount of Arctic warming has occurred in fall?

Because it's obviously not the only factor in play.

 

You're complicating certain aspects and oversimplifying others. It's a compelling fact Arctic sea ice has retreated, as has our ability to mansifest top-tier cold air masses. It's difficult to understand why someone would just discount it because they don't see stark proof of it.

[snow_wizard]

I don't think anyone is panicking...

 

And saying "if it can happen there it can happen here" doesn't sound like a statement grounded in science, no? 

 

We're talking about anomalies here.  Anomalies can happen anywhere.  If some places are seeing serious cold anomalies it should be possible anywhere.

[Front Ranger]

Because it's obviously not the only factor in play.

 

You're complicating certain aspects and oversimplifying others. It's a compelling fact Arctic sea ice has retreated, as has our ability to mansifest top-tier cold air masses. It's difficult to understand why someone would just discount it because they don't see stark proof of it.

I just don't see why the correlation would only manifest itself in mid winter.

 

I don't think I'm being unreasonable by pointing out there's more direct evidence that blocking is still the key factor.

[Deweydog]

I just don't see why the correlation would only manifest itself in mid winter.

 

I don't think I'm being unreasonable by pointing out there's more direct evidence that blocking is still the key factor.

Blocking is a huge factor. Obviously if zonal flow is in place the issue is moot.

 

The idea though that a lack of blocking is the key of keys is also pretty sketchy. We've seen many variations on prime blocking over the recent decades yet split flow at the 500mb level tends to de-ball these air masses from an upper level perspective.

[Phil]

As far as I understand, mid-latitude Rossby waves are driven by the equator-pole heat exchange. With a warmer Arctic, the temperature gradient between the tropics and the polar regions is lessened, thereby necessitating less poleward heat transfer - and less rebound equatorward transfer of cold air. Simply put, meridional flow in the mid-latitudes and the associated blocking isn't as strong with a warmer Arctic, in general. There can be exceptions on a case by case basis, as always.

I think it's a lot more than that.

 

Eddy/thermal/mass/momentum exchanges by latitude/longitude/altitude/depth/spatial frequency vary nonlinearly, in distinction from any number of boundary states. For example, a weakened equator/pole gradient above the Ferrel/Polar boundary boosts momentum deposition above the zero wind line hence increases upward transfer of heat/mass into the stratosphere/PV domain which promotes blocking/high pressures there. That's just one of many potential feedbacks, not even debating what could be forcing the enhanced warming with latitude (much of it had arisen via the poleward expansion/strengthening of the Hadley Cells since the late 1970s).

 

I don't think we can draw conclusions either way.

[Phil]

I think you're confusing modeling busts with actual patterns that occurred. It's pretty easy to see that the placement of the blocking was not optimal for any of those. They weren't great patterns where the air mass inexplicably wasn't very cold.

Could it be argued that the more "classic" blocking configurations are less likely to occur now, given significant changes in the Hadley/Walker Cells/Ratios, zero wind line(s), and photochemical processes in the upper atmosphere? I'd say it's quite possible.

[Phil]

They slid east because of how warm the Arctic is?

 

By the way, I think someone pointed this out earlier, but just look at Asia lately. They've been cold, over a huge area. And yet the Arctic has been warm! How are they getting cold when the Arctic, the source region, is a boiling cauldron of weenie anxiety???

 

Must be because they don't have the Rockies over there.

This is true. The expanse of the cold air over Eurasia is becoming historic, spatially speaking. Literally the entirety of Siberia, most of China, and Europe are currently in the freezer. This despite the warm Arctic.

 

The idea that the relatively tiny Arctic domain is the "source" for most/all of the cold air over the Northern Hemisphere is logically flawed. Physically speaking, the "source" is actually the upper troposphere and lower stratosphere above 40N.

[Front Ranger]

Could it be argued that the more "classic" blocking configurations are less likely to occur now, given significant changes in the Hadley/Walker Cells/Ratios, zero wind line(s), and photochemical processes in the upper atmosphere? I'd say it's quite possible.

 

Sure. That seems more plausible to me than pointing to the Arctic warming - especially since it's widely thought that Arctic warming leads to more high latitude blocking.

 

I'm curious why the affect would be more pronounced mid winter, for the western U.S. in particular.

[Front Ranger]

This is true. The expanse of the cold air over Eurasia is becoming historic, spatially speaking. Literally the entirety of Siberia, most of China, and Europe are currently in the freezer. This despite the warm Arctic.

 

The idea that the relatively tiny Arctic domain is the "source" for most/all of the cold air over the Northern Hemisphere is logically flawed. Physically speaking, the "source" is actually the upper troposphere and lower stratosphere above 40N.

 

Bingo.

[Phil]

That's not really what's being said.

 

You're right, it is partly a 500mb pattern issue (which is very likely linked at least partially to climate change, not to some sort of cycle that's about to "swing back" the other way). But its also a source airmass issue. The Arctic has warmed, so airmasses originating there are warmer on average than 50 years ago, for example. That's one of the reasons why some interior Alaskan stations show a 6F to 9F warming in DJF over the last 50 years. Colder airmasses that have a chance to linger in the Arctic build depth, which allows them to "spill over" mountain ranges more easily when they are steered S/SE. Think February 1989. This process happens less frequently as the planet (and especially the Arctic) warms, so terrain absolutely become more of an issue than in the past. I hope that clears things up a bit.

The thing is, if it were just about warming, Arctic blasts should have an equally difficult time breaking records here as they do out west. However, we've broken numerous cold records here, even in UHI locations, have observed at least 8 "top tier" blasts over the last 30 years (including two in 2013/14 and 2014/15), and have been demolishing snowfall records left and right. About 80% of our largest snowfalls over the last 150+ years have occurred during the last 20 years alone, which is just astonishing. Heck, some locations set their all time record lows for anytime during DJF with the Valentines Day blast in 2015, which was in mid/late February. Imagine if that had occurred a month earlier?

 

I think when one analyzes the (low frequency) global circulatory tendencies more closely, the significant shift that occurred during the late 1970s is obviously a player. The entire Hadley Cell climatology is different today. The seasonal Hadley Cell cycle over the NPAC is almost a full month slower than it was merely 75 years ago, and climate change alone cannot come close to explaining this. Something else is going on.

[Phil]

I'm curious why the affect would be more pronounced mid winter, for the western U.S. in particular.

I think some of this (not all of it) is just bad luck.

 

I've been looking through the NOAA/ESRL site (for an unrelated academic project), and the climatological changes in circulation are just huge since the late 1970s, and they're especially notable during the J/F/M period. The great NPAC/PDO climate shift that occurred then was largely a result of the abrupt Hadley/Walker reorganization and rapid expansion of the Hadley Cells.

 

As for why it occurred, we don't know but it started with the weakening of the BDC/cooling polar stratosphere which forced a warming of the Equatorial lower stratosphere/upper troposphere and a shift in the tropical convection. We really haven't looked back ever since.

[IbrChris]

Would love to see the teleconnection!

Here's a post I wrote on Nov 25, 2013 in the PDX WX Analysis Facebook group (join to view original):

 

"PAI - working on 12z runs. GFS Op dips down to -3.5 on Dec 5th with FIVE days below -2.7 from Dec 2nd through 6th."

[wx_statman]

No, it certainly isn't. Which is why I questioned the original assertion that a warmer Arctic may prevent us from getting cold this winter, or that it's a major culprit behind the lack of major mid winter blasts.

 

I think a better strategy is to educate yourself on the subject matter, before you take up a contrarian position as you have. The reality is that neither you or I are qualified to take a strong position one way or another in this conversation, since neither of us hold Ph.D.'s in Atmospheric Sciences or related subject areas.

 

As for me personally, I'm going off introductory knowledge of atmospheric dynamics and feedbacks to ground my assertions. The stuff they teach in intro-level courses to undergrads. I have a lot to learn as well, but I don't make it a point to continuously question complex matters that I don't fully understand. The Socratic Method has its time and place, but its not in the world of quantitative science. That's not how you learn this stuff. 

[Sometimesdylan]

October came in as the driest ever October on record for Juneau.

[Front Ranger]

I think a better strategy is to educate yourself on the subject matter, before you take up a contrarian position as you have. The reality is that neither you or I are qualified to take a strong position one way or another in this conversation, since neither of us hold Ph.D.'s in Atmospheric Sciences or related subject areas.

 

As for me personally, I'm going off introductory knowledge of atmospheric dynamics and feedbacks to ground my assertions. The stuff they teach in intro-level courses to undergrads. I have a lot to learn as well, but I don't make it a point to continuously question complex matters that I don't fully understand. The Socratic Method has its time and place, but its not in the world of quantitative science. That's not how you learn this stuff. 

 

Making unfounded assumptions is not very scientific. You do that several times in this post.

 

I think you'd agree that Phil is more educated than both of us on this particular subject. He agrees with me, by and large. Why you're ignoring that, I'm not sure. You certainly go out of your way to disparage and disagree with me.

[wx_statman]

I just don't see why the correlation would only manifest itself in mid winter.

 

I don't think I'm being unreasonable by pointing out there's more direct evidence that blocking is still the key factor.

 

For what its worth, please note the instances where I discussed blocking. Whether I'm right or wrong in my assertions, or something in between, doesn't take away from the fact that this is something that I've addressed. As far as I understand, a warmer Arctic is indeed tied to weaker mid-latitude blocking.

 

 

As far as I understand, mid-latitude Rossby waves are driven by the equator-pole heat exchange. With a warmer Arctic, the temperature gradient between the tropics and the polar regions is lessened, thereby necessitating less poleward heat transfer - and less rebound equatorward transfer of cold air. Simply put, meridional flow in the mid-latitudes and the associated blocking isn't as strong with a warmer Arctic, in general. There can be exceptions on a case by case basis, as always. 

 

I have a feeling such a flip won't be so easy in the PNW. We don't have a direct source of Arctic air like you do in the mid-Atlantic. Our Arctic airmasses have to traverse multiple high mountain ranges to get here, while traveling against the prevailing westerlies of the mid-latitudes. That means they need to be colder, deeper, and be steered by stronger upper level dynamics to make it to Portland or Seattle compared to the set of requirements necessary to steer Arctic air to Maryland. Global warming has made this process even more difficult to set in motion than in the past. With a reduction in Arctic sea ice and a later onset of fall/winter conditions in the Arctic, as well as significant winter warming seen in the Arctic in the last 50 years (as much as 6F-9F at some Alaskan stations, for example), Arctic airmasses don't generally get a chance to develop and deepen as much and as consistently as in the past. Perhaps more importantly for us, the strengthened N. Pacific Hadley Cell has made it that much more difficult for upper level troughs to come barreling down the western coast of North America, compared to even 25-30 years ago.

 

All of this means that there really isn't any switch to flip here, at least not with the way things look now. Until the climate cools again, we probably won't return to conditions seen in the 1950's here in the PNW.  

[wx_statman]

I think it's a lot more than that.

 

Eddy/thermal/mass/momentum exchanges by latitude/longitude/altitude/depth/spatial frequency vary nonlinearly, in distinction from any number of boundary states. For example, a weakened equator/pole gradient above the Ferrel/Polar boundary boosts momentum deposition above the zero wind line hence increases upward transfer of heat/mass into the stratosphere/PV domain which promotes blocking/high pressures there. That's just one of many potential feedbacks, not even debating what could be forcing the enhanced warming with latitude (much of it had arisen via the poleward expansion/strengthening of the Hadley Cells since the late 1970s).

 

I don't think we can draw conclusions either way.

 

Of course!

[wx_statman]

I think some of this (not all of it) is just bad luck.

 

I've been looking through the NOAA/ESRL site (for an unrelated academic project), and the climatological changes in circulation are just huge since the late 1970s, and they're especially notable during the J/F/M period. The great NPAC/PDO climate shift that occurred then was largely a result of the abrupt Hadley/Walker reorganization and rapid expansion of the Hadley Cells.

 

As for why it occurred, we don't know but it started with the weakening of the BDC/cooling polar stratosphere which forced a warming of the Equatorial lower stratosphere/upper troposphere and a shift in the tropical convection. We really haven't looked back ever since.

 

This is interesting stuff. You know a lot more about this subject matter than I do. 

[wx_statman]

Making unfounded assumptions is not very scientific. You do that several times in this post.

 

I think you'd agree that Phil is more educated than both of us on this particular subject. He agrees with me, by and large. Why you're ignoring that, I'm not sure. You certainly go out of your way to disparage and disagree with me.

 

Phil absolutely knows about this subject more than you or me. He's been studying this stuff at the college level for years. His arguments come off as scientific, so I'm willing to listen.

[wx_statman]

Making unfounded assumptions is not very scientific. You do that several times in this post.

 

I think you'd agree that Phil is more educated than both of us on this particular subject. He agrees with me, by and large. Why you're ignoring that, I'm not sure. You certainly go out of your way to disparage and disagree with me.

 

Unfounded assumptions? 

 

Please provide a link to your CV. I want to understand your level of knowledge of this stuff. Help me out. 

[Phil]

For what its worth, please note the instances where I discussed blocking. Whether I'm right or wrong in my assertions, or something in between, doesn't take away from the fact that this is something that I've addressed. As far as I understand, a warmer Arctic is indeed tied to weaker mid-latitude blocking.

Obviously we don't have the answers, however I think the majority of the peer reviewed literature is inconclusive on this. Either way the correlation is very weak, definitely not statistically significant, given so many factors influence the degree of blocking, some of which are very influential. I can post a few of the most recent papers if you're interested.

 

Generally speaking, a sharpening the equator/pole thermal gradient actually promotes an acceleration of zonal streamflow, which can either promote various forms of rossby wave breaking/blocking, or can enhance in a +NAM/+PV regime, depending on the nature of the areal boundary state and external forcings. The feedbacks are where things get complicated, and the thermal wind laws are funky as is.

[Sometimesdylan]

These discussions are great. Thanks to all parties involved here because the amount of information being shared is awesome. 

All I can do is link images that I've found on facebook and talk about what I've seen. Hope I am contributing...

 

http://i.imgur.com/y5FoCHk.jpg

[Front Ranger]

Phil absolutely knows about this subject more than you or me. He's been studying this stuff at the college level for years. His arguments come off as scientific, so I'm willing to listen.

And Phil acknowledges the large amount of uncertainty on this subject. My point from the beginning was that there isn't a lot to support the idea that a warmer Arctic currently plays a major role in prohibiting Arctic outbreaks. There is certainly more evidence that with the right blocking patterns, the West and the entire country can still see top tier cold - despite those "warm" temps up north.

 

It's a fallacy to think that a warmer Arctic automatically makes for a warmer "source" for cold air in the mid latitudes. Phil succinctly explained why already - you can't just look at the surface.

[Phil]

Here's a solid study on the potential relationship between high latitude blocking and "Arctic amplification". I personally consider this work to be well researched and reasonable, though my opinion doesn't mean much.

 

Spoiler: The authors found no statistical relationship either way.

 

http://onlinelibrary.wiley.com/doi/10.1002/2013GL058745/full

[Front Ranger]

Unfounded assumptions?

 

Yes, you assumed that I was uneducated on this and just taking a contrarian opinion. Just stick to logic and science, much more productive.

 

Or we can just go back and forth arguing over who is more contrarian here, making backhanded insults. But that would be stupid and a waste of time.

[Phil]

For what it's worth, the October AO value was just released and is easily the lowest value on record for that month since 1950. This in addition to a slew of record breaking blocks in both the EPO and AO/NAO in recent years. The only index that has failed to break any records (in either direction) is the PNA.

[wx_statman]

These discussions are great. Thanks to all parties involved here because the amount of information being shared is awesome. 

 

All I can do is link images that I've found on facebook and talk about what I've seen. Hope I am contributing...

 

http://i.imgur.com/y5FoCHk.jpg

 

That's a great graphic. 

[wx_statman]

And Phil acknowledges the large amount of uncertainty on this subject. My point from the beginning was that there isn't a lot to support the idea that a warmer Arctic currently plays a major role in prohibiting Arctic outbreaks. There is certainly more evidence that with the right blocking patterns, the West and the entire country can still see top tier cold - despite those "warm" temps up north.

 

It's a fallacy to think that a warmer Arctic automatically makes for a warmer "source" for cold air in the mid latitudes. Phil succinctly explained why already - you can't just look at the surface.

 

What I saw from you was mostly contrarian-themed questioning.

[wx_statman]

Here's a solid study on the potential relationship between high latitude blocking and "Arctic amplification". I personally consider this work to be well researched and reasonable, though my opinion doesn't mean much.

 

Spoiler: The authors found no statistical relationship either way.

 

http://onlinelibrary.wiley.com/doi/10.1002/2013GL058745/full

 

I'll definitely read that. 

[wx_statman]

Yes, you assumed that I was uneducated on this and just taking a contrarian opinion. Just stick to logic and science, much more productive.

 

Or we can just go back and forth arguing over who is more contrarian here, making backhanded insults. But that would be stupid and a waste of time.

 

Come on, Jared. You can't call yourself educated in this field unless you have a Ph.D. and years of research experience. 

[Front Ranger]

For what it's worth, the October AO value was just released and is easily the lowest value on record for that month since 1950. This in addition to a slew of record breaking blocks in both the EPO and AO/NAO in recent years. The only index that has failed to break any records (in either direction) is the PNA.

Of course, the PNA is a lower latitude index than the others. More comparable to the AMO, as you know.

 

That's cool news about the Oct -AO.

[Front Ranger]

What I saw from you was mostly contrarian-themed questioning.

As they say...you see what you want to see.

 

Stick to the actual discussion. Calling each other contrarian, which I could easily do as well, is not productive.