.......

[bluewave]

..........

 

[HailMan06]

Interesting:

Looks like further confirmation of what Jennifer Francis of Rutgers has been working on for the past couple years.

[calm_days]

Almost finished with the above presentation itself although I am sure there are important parts in the question and answer section as well.  Thank you for posting it, as it explains so much that was confusing me about waves, in recent memory.

 

This is the northern hemisphere today.  Many key ideas in her study are visible.

The slower propagation of waves causes more complicated blocking and occlusion features.  This week or few weeks ahead: it just looks like all of the bases are full, and, there is not some way to remove waves to make it stop. 

 

[Cheeznado]

Just look at what is happening in New England and the Atlantic right now with "Snowquester/Saturn". Stu Ostro of TWC has been gathering evidence about the increase of extreme blocking patterns increasing over the past several years. This results sometimes in seemingly counter-intuitive big slow moving snow events which prompt skeptics to cry "ha ha it's snowing so no GW".

[Jonger]

Just look at what is happening in New England and the Atlantic right now with "Snowquester/Saturn". Stu Ostro of TWC has been gathering evidence about the increase of extreme blocking patterns increasing over the past several years. This results sometimes in seemingly counter-intuitive big slow moving snow events which prompt skeptics to cry "ha ha it's snowing so no GW".

 

Only Joe Bastardi yaps his trap over every storm... but the whole blocking excuse by alarmists is completely horse 5hit as well.

[Cheeznado]

Only Joe Bastardi yaps his trap over every storm... but the whole blocking excuse by alarmists is completely horse 5hit as well.

So the above study was done by "alarmists"?

 

Your depth and insight are amazing.

[nzucker]

Didn't you read the lead story that I posted in the first link?

 

Stu Ostro was a prominent skeptic for quite some time until he started doing research

on his own along with reading the work of others. I don't see any alarmism

in trying to understand how warming is altering the weather patterns.

 

Except that it was said for years that global warming was causing less blocking and thus the warmer winters in the mid-latitudes, especially in Europe.

[blizzard1024]

This is all due to the shift of the Arctic Oscillation and NAO to more negative values which increases blocking

and leads to more cut off lows and slower moving systems and persistent anomalies. This has nothing to

do with global warming. This research does not explain why there was so much blocking during the 1960s and

1970s, a globally cool period, which was dominated by negative NAO and AO patterns. This is basic

teleconnections 101.  During periods of extreme cold during the little ice age there was evidence of

strong negative NAO patterns before GHGs were rising. All the recent research tying this to AGW

in my professional opinion is erroneous and just a way to blame the recent storminess on AGW.

The NAO and AO are always fluctuating.... basic stuff. No reason

to be alarmed and no way that global warming causes more negative NAO or AO patterns. It is

probably when the climate is cooler than we see more negative NAO/AO patterns based on

paleo records. 

 

 

 

[skierinvermont]

This is all due to the shift of the Arctic Oscillation and NAO to more negative values which increases blocking

and leads to more cut off lows and slower moving systems and persistent anomalies. This has nothing to

do with global warming. This research does not explain why there was so much blocking during the 1960s and

1970s, a globally cool period, which was dominated by negative NAO and AO patterns. This is basic

teleconnections 101.  During periods of extreme cold during the little ice age there was evidence of

strong negative NAO patterns before GHGs were rising. All the recent research tying this to AGW

in my professional opinion is erroneous and just a way to blame the recent storminess on AGW.

The NAO and AO are always fluctuating.... basic stuff. No reason

to be alarmed and no way that global warming causes more negative NAO or AO patterns. It is

probably when the climate is cooler than we see more negative NAO/AO patterns based on

paleo records. 

 

 

 

 

Well one argument being made is that the recent blocking is even more extreme than the 60s and 70s. 

 

 

And saying "AGW didn't cause the blocking the NAO did" is nonsensical. The NAO is just a specific type of blocking it isn't an explanation. The argument from some is that AGW is making the NAO and AO more negative (and other types of blocking too). I don't totally buy it yet either but there are some reasonable arguments and evidence out there for it. 

[PottercountyWXobserver]

Her studies are awesome! and I wish she would post more videos. Her audience wasn't very interesting nor did they ask any thought provoking questions. I want to know more philosophical questions regarding this theory. For example, with a warming gradient and thus higher wave amplitudes, shouldn't the flow eventually stall and cutoff? There should be an increase in cutoff lows right? Also with a warming gradient, eventually the strength of these systems should decrease? Someone should of asked if summer time features would become more semi-permanent if the ice where to completely melt out in the summers. For example the mid western summer ridge should become a semi-permenant feature as the jetstream becomes so weak allowing for extreme ridging to take place due to continental warming in the summer due to a stagnant and weak jetstream. So eventually when the thermal gradient becomes nearly equal? how does heat advect poleward and cool air advect towards the equator? Also with a more stagnant westerlies, could it be possible to see more easterly wind component events? Especially during the summer and fall months. Also could the weaker westerlies, wouldn't that theoretically inhance the chances of an east coast threat for a landfalling hurricane? This is because the stronger coldfronts will be unable to protect the east coast, especially in the earlier fall months?

[calm_days]

Here is a new northern hemisphere overview six days later.  I am considering starting a separate thread, but for now I will post these in here as they seem to fit the topic.  There has been some overall change in just six days which is a relief.

For me it is less worry about warming than worrying a little about the patterns, trying to see how they will develop and hoping that some kind of safe balance finds its way into them over time.

 

[skierinvermont]

They couldn't know at the time of the older studies how rapidly the Arctic sea ice would decline.

 

 

6a0133f03a1e37970b017744cf5360970d.jpg

 

Well that could explain July August September , but sea ice in all the other months has declined around the expected rate the last 7 years. 

[csnavywx]

Maybe in terms of area or extent, which has diminished in importance (still useful) with the improvements in volume measurement. Volume collapses in the past few years have been pretty astounding, and reveal much more damage to the ice pack than the extent/area metrics do.

[skierinvermont]

Maybe in terms of area or extent, which has diminished in importance (still useful) with the improvements in volume measurement. Volume collapses in the past few years have been pretty astounding, and reveal much more damage to the ice pack than the extent/area metrics do.

 

 

Check the context of my statement. Thin ice doesn't cause blocking. Low extent might. The atmosphere doesn't know whether the ice is 1m thick or 2m thick. 

[nzucker]

Check the context of my statement. Thin ice doesn't cause blocking. Low extent might. The atmosphere doesn't know whether the ice is 1m thick or 2m thick. 

The problem is that the ice was near all-time highs in the 1960s and 1970s, when we saw some of the most extreme blocking. Global temperatures were also much cooler at that point, even cooler than the 40s and 50s, and yet blocking was increasing, which doesn't jive with the recent argument.

 

Also, Greenland warmed during the Little Ice Age, indicating that there was a persistent -NAO during a very cold period globally when sea ice was almost certainly higher than it was during the Medieval Warm Period. Alaska was also believed to be milder during the Little Ice Age, another sign of increased high latitude blocking in a cold global/high sea ice regime.

 

I think more logical explanations for the increased prevalence of blocking are the solar minimum as well as just a natural cycle...we couldn't go 50 winters in a row without Europe getting the -NAO they needed. 

[WXheights]

They couldn't know at the time of the older studies how rapidly the Arctic sea ice would decline.

 

 

6a0133f03a1e37970b017744cf5360970d.jpg

 

Thanks for this Bluewave.  We certainly live in an interesting time, you could say in "geological scale New Bulletin" times when summer sea ice may be non existent for some portion of late summer in the relative near future, this is beyond huge if you understand perspective scale!! With sea ice extent/volume tanking polar amplified warming = increased thicknesses more blocking slowing progressive mean wave trough ridge train, drought/flood hydrological scale amplified, is a pretty hairy experiment at this end of the Holocene optimum. 

[ORH_wxman]

But the heights have been rising in tandem with the temperatures and are higher than they were 

when the planet was cooler.

 

Screen shot 2013-03-10 at 8.08.47 AM.png

 

 

Higher heights and "blocking" are not necessarily the same thing. They often are, but if you just have generally higher heights in a semi-zonal flow but not an actual block in place, then you don't have blocking.

 

Also the chart you show indicates much higher heights in the 1980s/1990s than the 1960s which had significantly more blocking than the latter period. Maybe we need to look at relative heights of the arctic to other areas.

[skierinvermont]

Higher heights and "blocking" are not necessarily the same thing. They often are, but if you just have generally higher heights in a semi-zonal flow but not an actual block in place, then you don't have blocking.

 

Also the chart you show indicates much higher heights in the 1980s/1990s than the 1960s which had significantly more blocking than the latter period. Maybe we need to look at relative heights of the arctic to other areas.

 

Indeed.. blocking is a relative measure. I'm still guessing the blocking in recent years is the most extreme on record, which is part of the argument. 

[ORH_wxman]

When we plot a record for 500mb anomalies in the arctic circle, what base period are we using? (I.E. does an anomaly record set in 2010 use a 1981-2010 base period while a 1977 record also uses the 1981-2010?)

I think that would be an important distinction to make when we claim record blocking. The heights everywhere are higher than decades ago, so if we don't adjust for the base period and only use '81-'10 climo, that would make the earlier blocking look less impressive than it actually was. I'm wondering if we have adjusted the base period for earlier blocking episodes.

I still think the peak of the 2010 blocking would not be beaten even if we have not adjusted the base periods, but when comparing still strong, but less extreme blocking to the past, the base periods could make a distinct difference.

[skierinvermont]

A few points bluewave and ORH:

 

1. Anomalies are not actually a good measure, whether we use centered base periods or not. What we are looking for is how big the blocking is compared to the rest of the earth. Anomalies are a comparison to a medium-term (or long-term) average in the same region/location. If the average in the arctic rises faster than the rest of the earth, that would mean more blocking and less zonal flow, but it wouldn't mean the anomalies rise. This point is a reply to ORH's post above.

 

2. The first list of records is "anomalies" which I don't find very useful for the above reason. Also most of the dates on the list are pre-2000, although the #1 spot is 2010. But this may be related to my first point. 

 

 

3. The rest of the records are absolute heights. The fact that more records are modern is not surprising given mean heights globally have been rising.

 

 

4. The last several plots showing zonal long-term height rises don't show the arctic rising much faster than the mid-latitudes. That doesn't really support an argument for increased blocking. 

 

 

5. What we need is a list of max height records which subtracts out the global height anomaly at the time of the record.

 

 

So for example, if global height anomalies have risen by 20mb since 1970 and we subtract 20mb from all the events in the 2000s on bluewave's last two lists of records, well then the Jan 2011 event still holds onto the top 5 daily records although the 5th one moves into a near tie with January 16 1977. #7 (Jan 3 2010) falls off the list entirely. As does Jan 6 2006. 

 

 

Dec 16 2010 still would hold #1 on the december list, but by a much smaller more reasonable margin. Dec 11 2001 would move from tied in 3rd to tied in 10th. Dec 15 2010 would also move from tied in 3rd to tied in 10th. 

 

 

 

In short, the January 2011 event would still hold several of the top January daily mean records. 

 

The December 2010 event would move down or off the list. As do several other January and December records set in the 2000s.

[ORH_wxman]

I agree with your point #1...that's what I was getting at originally. The heights relative to the rest of the globe. I didn't re-specify that when I made my latest post, but using anomalies vs the rest of the globe you'd still want to calibrate the base period unless there is an easier way to just measure the straight difference. I'm not sure there is at our easy disposal, but I'm sure it can be calculated with reanalysis data.

[skierinvermont]

I still think the peak of the 2010 blocking would not be beaten even if we have not adjusted the base periods, but when comparing still strong, but less extreme blocking to the past, the base periods could make a distinct difference.

 

 

Using the crude 20mb adjustment to the 2000s I did above definitely supports the above point. The 5-day period in 2011 still stands out, but by a smaller margin. All the other modern events move down or off the records list.

[ORH_wxman]

Using the crude 20mb adjustment to the 2000s I did above definitely supports the above point. The 5-day period in 2011 still stands out, but by a smaller margin. All the other modern events move down or off the records list.

 

 

That makes sense. The blocking episodes in the late 1970s and some of the late 50s/1960s events were pretty extreme, so it was a bit weird to see them below other recent events.

 

Even though the NAO is only one aspect of blocking, I noticed the SLP method (where the difference in Iceland and Azores pressure is used) didn't inflate recent -NAO periods like the CPC height anomaly method did.

[skierinvermont]

I think that your are making a more of a semantic argument. The bottom line is that the weather patterns have been slowing

down and becoming more extreme as the heights have been building as shown by numerous recent papers. Proposing

new ways to measure what we already know doesn't change that. 

 

Blocking has been increasing across the different zones. All you have to do is plug in dates around

the peaks of the 500 mb zonal heights that have been steadily rising. Around those dates you will 

find blocking episodes at different latitudes. So I don't see your argument that blocking hasn't been

increasing. The paper that I linked to has charts which show blocks in different locations and latitudes

associated with extreme weather.

 

The record warmth last March was the result of the strongest  March  blocking since 1950 centered over the Great Lakes.  

 

 

 

March.png

 

The Hurricane Sandy block was higher latitude based.

 

0ct.png

 

 

My point is that once you adjust for the rise of heights globally, there really hasn't been much trend for increased blocking. 

[calm_days]

This does not appear to have been a trapped wave, but it was extreme: happening March 12th over China.  The look on the map that surprised me so I wanted to archive it here.  It can be seen well on the visible satellite image so I will share that too.

 

 

 

Visible image:

[skierinvermont]

Maybe you are using a different definition of what you consider blocking to be. There is some subjectivity in the 

literature in the way blocking is measured. But the recent papers are showing the current patterns slowing down

or getting stuck which would constitute increased blocking of the weather patterns for the sake of this discussion.

So we may be using different terms  to describe the same general situation.

 

Which other papers are you referring to besides the one in the OP? The OP mentions a "significant increase with 90% confidence" but I would like to see the time period they are referring to and how they are defining it. If they did 2000-2012 or 1990-2012 then yeah... big increase. 1950-2012 ... no. 

[ORH_wxman]

Maybe you are using a different definition of what you consider blocking to be. There is some subjectivity in the 

literature in the way blocking is measured. But the recent papers are showing the current patterns slowing down

or getting stuck which would constitute increased blocking of the weather patterns for the sake of this discussion.

So we may not be able to agree on the precise language for what we have been observing.

 

 

There sure is. Traditional blocking means there is an actual block in the weather pattern, not just above normal heights. The stats about "highest height ever observed" in certain parts of the arctic are pretty irrelevant to the conversation since heights overall have gotten higher in general. I mean, by the year 2070 we could have heights in the arctic that blow away the 2011 blocking scenario but the blocking itself (as in the cutting off of the upper flow) is completely pedestrian. So its important to make a distinction.

 

Its important to not overstate a trend.

[calm_days]

For now it does still make sense to share a new satellite map here, to be compared to the other images saved here. 

 

 

Here is a closeup of the area over Eurasia which is one of the more interesting wave/low interactions.  

 

[JBG]

Only Joe Bastardi yaps his trap over every storm... but the whole blocking excuse by alarmists is completely horse 5hit as well.

And what have the alarmists said that isn't horse manure?

[calm_days]

Whether this topic as it stands now (title and posts removed) represents a play/satire at climate change censorship by bluewave (I saw the topic in its original form about a month ago), or something else, it should reenter the flow of current topics to be seen by others in this form.  There is a new topic about the original subject matter; this can be for discussing whatever happened to this topic.