Snowmageddon warnings in North America come from tropics more than Arctic stratosphere

First ever study of how North America’s four main weather regimes are affected by polar vortex strength

University of Reading


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The four US weather regimes (clockwise from top left): Pacific Trough, Arctic High, Alaskan Ridge, Arctic Low. Red indicates warmer conditions and blue colder conditions

Credit: Simon Lee

Winter weather patterns in North America are dictated by changes to the polar vortex winds high in the atmosphere, but the most significant cold snaps are more likely influenced by the tropics, scientists have found.

A team led by the University of Reading conducted the first ever study to identify how the four main winter weather patterns in North America behave depending on the strength of the stratospheric polar vortex. This is a ribbon of wind and low pressure that circles the Arctic at heights of 10-50km, trapping cold air inside.

It is already well established that the vortex wind strength influences weather in Europe and Asia, and the study revealed it also has a strong effect on three out of the four main winter weather patterns in North America, giving forecasters an additional tool to understand potentially high-impact weather during winter.

The study, published in Geophysical Research Letters, also revealed that, unlike in Europe, the most extreme cold snaps affecting the whole of North America are not most likely to occur after a weak vortex. Instead, the shape of the vortex and conditions in the tropics were identified as stronger influences of these conditions.

Simon Lee, atmospheric scientist at the University of Reading and lead author of the study, said: “Despite the most extreme cold snaps experienced in North America often being described as ‘polar vortex outbreaks’, our study suggests vortex strength should not be considered as a cause.

“We know that a weakened polar vortex allows cold air to flood out from the Arctic over Europe and Asia, but we found this is surprisingly not the case the other side of the Atlantic.

“In fact, our work suggests we should actually look south to conditions around the equator, rather than north to the Arctic, for the causes of these widespread freezing conditions in North America.

“Our results did reveal that the polar vortex strength provides useful information on the likelihood of most weather patterns over the US and Canada further in advance, including some potentially disruptive temperature changes or heavy rain. The more accurate information populations have about upcoming changes in weather, the better they can prepare.”

One of the clearest suggested effects of a strong vortex was a 10-15% likelihood of extremely cold conditions in western parts of North America, including Alaska, but milder conditions in central and eastern parts of the US.

Another weather pattern found to most often follow neutral or strong vortex wind speeds brings temperatures 5°C above normal and wetter weather in the eastern US.

The exception in the results was that the weather pattern associated with the highest chance of the most widespread extreme cold in North America, in which average temperatures in the central US are more than 5°C below normal, was not found to have a strong dependence on a weaker vortex, as it does in Europe.

They found widespread extreme cold is more common when an area of high pressure extends up to Alaska, and the polar vortex stretches down towards North America – pushing cold Arctic air southward in the lower atmosphere.

The scientists say the influence of the stratosphere on weather patterns, as well as how this interacts with long-term weather patterns in the tropics like El Niño, should be studied further and incorporated into forecasts to improve their accuracy.

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From EurekAlert!

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Tom Abbott
December 28, 2019 6:27 am

That article didn’t really give me much insight into how the climate works.

It’s probably true that the coldest winters in the U.S. are when a high pressure system sits up around Alaska which has the consequence of directing cold arctic air down into the United States.

I think the question is why does this high pressure system establish itself here.

Reply to  Tom Abbott
December 28, 2019 6:53 am

re: “I think the question is why does this high pressure system establish itself here.”

Let’s start with what’s known: ‘Descending air’ in the middle of a high pressure system.

Krishna Gans
Reply to  Tom Abbott
December 28, 2019 8:01 am

It can’t give any insights how climate works, because the study is about US winter weather

Michael Jankowski
Reply to  Krishna Gans
December 28, 2019 10:05 am

Krishna the data covers 1979-2017. Dominant winter weather patterns for almost 40 yrs are climate.

Krishna Gans
Reply to  Michael Jankowski
December 28, 2019 10:44 am

“The scientists say the influence of the stratosphere on weather patterns, as well as how this interacts with long-term weather patterns in the tropics like El Niño, should be studied further and incorporated into forecasts to improve their accuracy.”
The data may cover a climate periode, but the study refers to weather prediction possibilities

Johann Wundersamer
Reply to  Michael Jankowski
January 8, 2020 9:58 am

“Weather” is reigned by the quasi biennial oscillation, too – and that genuinely is “Climate”:

https://www.google.com/search?q=quasi+biennial+oscillation&oq=quasi+bi&aqs=chrome.

Curious George
Reply to  Tom Abbott
December 28, 2019 9:31 am

It is difficult to say “we don’t know” in so few words.

HotScot
Reply to  Curious George
December 29, 2019 3:48 am

Curious George

HeHeHe……Wkd. 🙂

Carbon Bigfoot
Reply to  Tom Abbott
December 28, 2019 3:32 pm

As Joe Bastardi of Weatherbell Analytics– the Madden Julian Oscillation describes the process. It essential starts with Indian Ocean dipole moment and thunderstorms releasing enormous amounts of heat in the upper stratosphere forming the Artic Highs.
Historical analogue information has been known for years to cause cold Winters. This December warmth is a prelude to a very cold Jan-March this year.
As new subscriber to Weatherbell Analytics that is what Joe has suggested. If I’m wrong in that assessment and your out there Joe please correct my evaluation.

posa
Reply to  Carbon Bigfoot
December 28, 2019 7:58 pm

Totally agree. JB has provided a lucid explanation of how the winter season will evolve the way you stated… see the Saturday Weekly summary (free) at Weatherbell.com… excellent stuff. JB is ruthlessly honest about delusions on both sides of the climate debate, and is just as tough on himself when his predictions fail (and why they failed).

Reply to  Carbon Bigfoot
December 29, 2019 5:25 am

Joe has a wonderful ability to remember similar maps from the past, but a computer can bring up analog maps. What Joe also recalls is the motion in the map. A map of a ridge and a trough is a static thing. Joe remembers if the ridges and troughs were digging or lifting.

Me? I make a wild guess and then sit back to see how wrong I can be.

It has recently been interesting to watch how the cold built at the Pole and especially in Alaska and the Canadian Archipelago the moment the flow around the Pole became quasi-zonal.

https://sunriseswansong.wordpress.com/2019/12/28/aectic-sea-ice-slack-tide/

December 28, 2019 6:30 am

This justifies a return to my old hypothesis set out here:

https://www.newclimatemodel.com/is-the-sun-driving-ozone-and-changing-the-climate/

whereby jet stream waviness is a consequence of the interaction between a top down solar effect above the poles and a bottom up oceanic effect from the tropics.

The result of more such waviness is increasing extreme episodes of both warm and cold but overall increased global cloudiness that eventually cools the whole climate system.

Mike Maguire
Reply to  Stephen Wilde
December 28, 2019 8:34 am

Stephen,
I read the explanation for your theory for the first time several years ago. It makes complete sense to me.

Reply to  Mike Maguire
December 28, 2019 12:18 pm

Hi Mike,
It makes sense to a lot of people but those who ought to be investigating the concept are simply ignoring it.
Not convenient, politically.

Krishna Gans
December 28, 2019 6:34 am

When I read “first ever study of”… is my feeling, it didn’t worth a study.

Latitude
Reply to  Krishna Gans
December 28, 2019 8:41 am

…something weather forecasters have known for decades

commieBob
December 28, 2019 6:47 am

The troposphere is the lowest layer of Earth’s atmosphere. The troposphere starts at Earth’s surface and goes up to a height of 7 to 20 km (4 to 12 miles, or 23,000 to 65,000 feet) above sea level. Most of the mass (about 75-80%) of the atmosphere is in the troposphere. Almost all weather occurs within this layer. link

So, given that most of the atmosphere is below the polar vortex why would it have much influence on the weather?

Is it possible that conditions in the troposphere influence the stratosphere and not vice versa?

Reply to  commieBob
December 28, 2019 6:51 am

Because the temperature of the lower stratosphere over the poles affects the height of the tropopause over the poles and thus alters the gradient of tropopause height between equator and poles.
Changes in that gradient affect Jetstream behaviour and overall global cloudiness.

Krishna Gans
Reply to  Stephen Wilde
December 28, 2019 7:50 am

Weak sun activity with less UV radiation lets shrink the atmosphere.
(TCI)

LdB
Reply to  Krishna Gans
December 28, 2019 5:26 pm

That relies on the quirky climate science definition of “atmosphere”. If you look at this years SWAN instrument paper you will see Earth hydrogen molecules extend 640,000 Km into space way past the moon. So you could say that it the atmosphere boundary.

Probably stick to the name you are talking about which is the thermosphere, and leave the word atmosphere alone.

Krishna Gans
Reply to  LdB
December 29, 2019 1:54 am

At spaceweather.com you find an explanation of the TCI and the data too.

wayne job
Reply to  Krishna Gans
December 28, 2019 10:27 pm

Krisna I am wondering if the weird high speed jet streams are a consequence of the sun being quite. The other question that comes to mind is did this happen before the LIA??

rbabcock
December 28, 2019 7:05 am

Since North America is surrounded by copious amounts of warm water in the winter on its southern flank (Pacific off California, the Gulf of Mexico and the Atlantic south of Cape Hatteras), all you need to do is get the winds blowing in from the southwest, south or southeast to hit the arctic air coming in from the north and bingo, you can have Snowmaggadon.

I’m not so sure many people living in North America don’t know this already. It happens once or twice a winter.

beng135
December 28, 2019 7:37 am

Of course the weather is influenced by the tropics. That’s the weather-engine that drives all the other “parts”, all the way to the poles.

Enginer01
Reply to  beng135
December 28, 2019 9:26 am

Svensmark’s attempts to sell GCR affects on the earths albedo (cloudiness) seems to revolve around Willis Eschenbach’s Equatorial Convergence zone. I started following the https://wattsupwiththat.com/2007/10/17/earths-albedo-tells-a-interesting-story/ (Great Bear Observatory) work years ago, and it seems that the basic science is still not confirmed.
Alarmists still say the solar radiation changes cannot explain climate, but they refuse to accept the amplification effects provided by cloud formation.

Krishna Gans
Reply to  Enginer01
December 28, 2019 9:35 am

And the changing UV radiation during solar cycle affecting the ozone layer, the temperature of the thermosphere…

John F. Hultquist
Reply to  beng135
December 28, 2019 9:31 am

. . . because that is where the greatest energy is.

DMacKenzie
December 28, 2019 7:40 am

“..our work suggests we should actually look south to conditions around the equator….for the causes of these widespread freezing conditions in North America.”
What a crock! These people just think the tax paying public is dumb enough to fund their “research”…

Editor
Reply to  DMacKenzie
December 28, 2019 3:10 pm

I had a very frustrating conversation recently with a self-described climatologist and IPCC reviewer. I tried to explain why the climate models could never work but they wouldn’t listen. They just kept repeating that the models simply followed the rules of physics. So the answer to this issue is remarkably simple: just look at the climate models’ runs from just before these temperature patterns appeared and the models will (a) show the temperature patterns as just experienced, and (b) explain why they occurred.

Either that, or the models really will never work.

Pochas94
Reply to  Mike Jonas
December 28, 2019 4:41 pm

Oh they’ll work, but not for a long, long time.

French geographer
December 28, 2019 7:40 am

For understanding the movements of atmosphere, read Marcel Leroux ! His Mobile Polar Anticyclone explains why North America can be frozen, not an alledged “vortex”.

Reply to  French geographer
December 28, 2019 8:01 am

Leroux was referring to the tendency of northern high pressure regions in the troposphere to drift equatorward taking cold air with them.
That is consistent with my hypothesis concerning changes in the gradient of tropopause height between equator and poles.
You will note that changes in the stratospheric polar vortex (which contains descending adiabatically warming air that depresses the tropopause over the poles) can facilitate the equatorward drift.

Tom Abbott
Reply to  Stephen Wilde
December 28, 2019 8:23 am

“Leroux was referring to the tendency of northern high pressure regions in the troposphere to drift equatorward taking cold air with them.”

I think that describes what we see. High Pressure systems drift around unless acted upon by an outside force. Sometimes high pressure systems practically stop over one location for a period of ttime..

Krishna Gans
Reply to  Stephen Wilde
December 28, 2019 8:33 am

These Leroux MPH are mostly small ones at a very low hight.

TomRude
Reply to  Krishna Gans
December 28, 2019 9:15 pm

Not at all: they could be hemispheric sized MPHs.

Krishna Gans
Reply to  TomRude
December 29, 2019 1:49 am

They could, yes, but Leroux’ observatios found a lot of small ones too over days and weeks. That’s the base of his work.

Mike Maguire
Reply to  Stephen Wilde
December 28, 2019 8:45 am

The oceans have tremendous thermal inertia ……….having stored massive amounts of heat from solar energy of previously active periods of the sun…………..which is still coming out after the sun has morphed to being less active.

This lag between the peak in heating of the oceans from the sun and when the oceans burping out that heat is exhausted is probably, at least a decade.

TomRude
Reply to  French geographer
December 28, 2019 9:25 pm

Indeed. The “Polar vortex weakening” supposedly “permitting cold air to escape the polar regions” cannot be based on factual observations. Synoptic analysis of satellite imagery shows cold air masses in the lower troposphere constantly move from the polar regions toward the tropics, regardless of the season.
Using averages tends to obliterate the real working of circulation hence those “Azores anticyclone” types of so called action centers. Observing circulation at work is truly the first order of business for anyone.

Tom Abbott
December 28, 2019 7:58 am

Here’s what the jet stream looks like today according to Nullschool:

https://earth.nullschool.net/#current/wind/isobaric/500hPa/orthographic=-101.92,51.66,660

The jet stream is taking a deep dip into the lower United States.

Tom Abbott
Reply to  Tom Abbott
December 28, 2019 8:26 am

The good part about the jet stream dip into the lower U.S. is it is bringing in tropical air off the Pacific ocean, not arctic air.

chemman
Reply to  Tom Abbott
December 28, 2019 9:17 am

Which accounts for the snow the last couple of days in my neck of the woods. And yes Virginia it does snow in the high altitude areas of Arizona.

KcTaz
Reply to  chemman
December 28, 2019 10:14 am

chemman, yes, it does and the White Christmas was lovely!

Scissor
Reply to  Tom Abbott
December 28, 2019 8:53 am

I’m in the loop that has dipped down through the Rockies. There is little wind but I woke to a few inches of white stuff this morning, just enough moisture being brought up from the south to be frozen out by the northern cold.

Ed Zuiderwijk
December 28, 2019 8:03 am

European MSM making a lot if the lack of snow in Moscow, because, of course, climate jitters. That it all seems to have gone to Minnesota is not mentioned, of course.

Mark
December 28, 2019 9:17 am

@Krishna Ghans: When I read “first ever study of”… is my feeling, it didn’t worth a study.
@Lititude: “…something weather forecasters have known for decades”.

Very true!!
It again shows how peer review works for some particular group of climate scientists. Actual innovative research from true scientists will suffer a long delay and most of the time will be rejected; whereas silly and known ideas are getting published so quickly in renowned journals.

Rich Davis
December 28, 2019 9:40 am

I start with the fact that it comes from EurekAlert! and proceed to the fact that it is research conducted at the University of Reading, before concluding with this question. Are they just correlating weather outcomes with stratospheric conditions and assuming causation? If the same “study” is repeated with next year’s conditions, will it contradict what “we know”? Null hypothesis anyone?

Michael Jankowski
Reply to  Rich Davis
December 28, 2019 10:09 am

I start with the fact that the study covers 1979-2017, not just one year.

Rich Davis
Reply to  Michael Jankowski
December 28, 2019 11:35 am

Ok, substitute the next four decades for next year if you like, it doesn’t touch my point.

Are they inferring causation from correlation, or aren’t they? The reason I ask is that they claim to “know” that polar vortex causes cold events in Europe, but “surprisingly” not in North America. No hypothesis about the physical mechanism involved or what should be different in the North American case. If there is a physical process that is responsible for the correlation they discovered, why would the process not be applicable everywhere at the same latitude?

So that sounds a lot like the rooster crowed and then the sun came up, therefore sunrises are caused by rooster crowing (on the farm). Then we checked a place with no roosters, and “surprisingly”, the sun still came up. Apparently in those areas, song birds chattering are more responsible for sunrise. However, in a few cases we observed alarm clocks having a strong effect.

Reply to  Rich Davis
December 28, 2019 12:14 pm

It is a matter of geography.
Arctic high pressure regions with their associated cold air can easily slip eastwards and southwards across the continental land mass to the east of the Rockies but such regions forming west of the Rockies cannot easily propagate eastwards so they tend to move southwards and are easily dissipated by warm Pacific waters to the south. Water has a hugely greater heat capacity compared to air.
As always, a knowledge of basic meteorology provides answers.

Rich Davis
Reply to  Stephen Wilde
December 28, 2019 12:51 pm

What part of that involves a mechanism that depends on the stratosphere? And is that their hypothesis, or just yours? Your explanation can be perfectly correct without their correlation being a reflection of any physical reality.

Reply to  Stephen Wilde
December 29, 2019 12:19 am

The temperature of the stratosphere above the poles influences tropopause height above the poles and thus the likelihood of equator ward surges of cold higher pressure air in the troposphere.

John F. Hultquist
December 28, 2019 9:47 am

“Waiting on the Polar Vortex” sounds like a song title.

Those of us that live in the real world have to prepare for sun, wind, rain, snow, and cold well in advance of any forecasts.
When you have outside animals you best should fix the frost-free faucet and the heater on the water tank, and not wait until the researcher models claim it might get cold.
Same with firewood, snow tires, and a warm coat. October, in the NH, is a good time to get these things done.

ren
December 28, 2019 10:03 am

The distribution of ozone in the stratosphere and the associated polar vortex pattern depend on the strength of the geomagnetic field and the solar magnetic field. When the solar wind weakens, the polar vortex pattern follows the geomagnetic field pattern in the north.
http://sol.spacenvironment.net/raps_ops/current_files/Cutoff.html
https://www.esa.int/Applications/Observing_the_Earth/Swarm/Our_protective_shield

Brandon
December 28, 2019 10:06 am

Another stupid question: does the position of the magnetic pole have any affect on regional temperatures at all?

ren
December 28, 2019 10:11 am

Currently, a strong wave is operating in the upper stratosphere, which results from the weakening of the stratospheric polar vortex by one-sided inflow of ozone to the polar circle.
comment image
comment image
comment image

ren
December 28, 2019 10:17 am

The wave from the upper stratosphere eventually moves into the troposphere, directly affecting the weather.
comment image

Wxcycles
Reply to  ren
December 30, 2019 3:13 am

It will be on around 8th Jan in central US, an elongated High from Canada to the gulf coast with deep cold in the NE pulled down to the GOM.

ren
December 28, 2019 10:19 am

This is now the distribution of ozone in the north.
comment image

KcTaz
December 28, 2019 10:22 am

I found this article on the sun’s effect on the Jet Stream very interesting. I would be interested in thoughts on this.

“Meridional Jet Stream” Upsets Europe’s Apple –and Pear– Cart
http://bit.ly/2ZVxp2B

August 8, 2019
Europe is forecasting a sharp reduction to its apple and pear crop this season after a long-lasting spell of Spring cold followed by a brief (but much-documented) burst of July heat dealt production regions something of a one-two punch — yet another example of the Swings between Extremes brought on by a wavy jet stream, which itself is associated with historically low solar activity.
…Furthermore, some regions of the planet actually warm during times of global cooling — the Arctic, Alaska and N Atlantic/S Greenland to name a few (though ‘warm’ to the Arctic, for example, still averages well-below zero, there is no additional melt):
Temp change between 1780 (a year of normal solar activity) and 1680 (a year within the depths of the Maunder Minimum) — NASA
Earth’s climate is cyclic, never linear — driven by the sun.
And history is repeating, our star is again shutting down (relatively).

ren
Reply to  KcTaz
December 28, 2019 11:49 am

The SSW, which is already visible in January, may once again prolong the waves of frost in Europe until April.

ren
December 28, 2019 10:33 am

Currently, an anomaly of stratospheric ozone over western US is visible.
comment image
comment image

Michael Carter
December 28, 2019 11:46 am

The 2 MSM companies that control 80% of news publications in New Zealand are making big over a warm marine blob centered ~ 2000 km off our east coast. They then go on about tropical fish having been observed further Sth than ever and publish comments from the most extreme alarmist scientist in NZ. They make no mention of the cold trend surrounding the country.

comment image

This cold zone has been creeping north and intensifying over the last month. Balanced journalism would surely discuss both phenomenon. The US and Australia have media that balance the debate, but NZ has none. We are now subjected to daily sermons with no means of reply.

M

December 28, 2019 1:46 pm

Snow coming from the Tropics…..Heh, Heh,…..maybe that’s something we should be looking out for in Queensland next winter.

Sara
December 28, 2019 2:07 pm

Snowmageddon again? Yeah, we had that last winter and this time, deep cold and snowy winter is keeping itself out of my AO. And it can stay out! I don’t want to shovel snow this winter!!

December 28, 2019 3:13 pm

For the tropical connection, this left off 3 very important words – Madden-Julian Oscillation…

December 28, 2019 5:33 pm

Ozone is a good tracer, as it defines the boundaries of cold air parcels like the polar vortex, an ironically good use for a trace gas 50-200X less concentrated than CO2; but it’s not a good basis for a climate theory, nor is the thermosphere, neither control the ocean temperature or the tropics.

“An interesting feature of stratospheric circulation is the QBO in the tropical latitudes, which is driven by gravity waves that are convectively generated in the troposphere. The QBO induces a secondary circulation that is important for the global stratospheric transport of tracers, such as ozone[11] or water vapor. ”

https://en.wikipedia.org/wiki/Stratosphere, and reference [11]

“About 90 percent of the ozone in the atmosphere is contained in the stratosphere. Ozone concentrations are greatest between about 20 and 40 kilometres (66,000 and 131,000 ft), where they range from about 2 to 8 parts per million. If all of the ozone were compressed to the pressure of the air at sea level, it would be only 3 millimetres (1⁄8 inch) thick.[6]”

https://en.wikipedia.org/wiki/Ozone_layer

beng135
Reply to  Bob Weber
December 29, 2019 7:43 am

but it’s not a good basis for a climate theory, nor is the thermosphere, neither control the ocean temperature or the tropics.

Agree.

Denny Collins
December 28, 2019 7:52 pm

It is the sun, lack of sunspots creates a a lack of magnetic pull, this upsets the polar vortex and jet stream and thus we have weather issues. How do we not all see this. It is so obvious.

Harry
December 29, 2019 1:24 am

In the seventies and eighties, the Netherlands had cold snaps almost each year, you could always ice skating on the canals. There where only a few in the nineteens, ice skating on canals is becoming very rare. The EU will use climate change to destroy democratie and soeverainity. Our only chance is the return of very cold winters that destroys their narrative, but i do not see happened and the msm will not mention the cold in usa.

ren
Reply to  Harry
December 29, 2019 6:51 am

This year it will be different, because circulation in the Eastern Atlantic is blocking.

GeologyJim
December 29, 2019 6:31 am

Question from a non-meteorologist:

I think it is backward to speak of the “polar vortex “ as the active agent of high latitude weather systems.

It would seem that the distribution and intensity of high and low pressure zones determines areas that are relatively warmer or cooler

The vortex winds are a response to the natural rotation of atmospheric flow around these high/low pressure zones. Stronger vortex winds reflect greater pressure differentials, and vice-versa for weaker winds

Am I on the right track here? If not, I am more than happy to be educated

ren
Reply to  GeologyJim
December 29, 2019 7:30 am

In winter, the distribution of air masses is determined by the jetstream , which is in the tropopause. Stratospheric waves at high latitudes generate waves in the upper troposphere. This is clearly seen up to a pressure level of 500 hPa.
https://earth.nullschool.net/#current/wind/isobaric/250hPa/orthographic=-341.96,88.89,340

TomRude
Reply to  GeologyJim
December 29, 2019 4:20 pm

Jim, there are two schools: the altitude one that seems to prevail these days, claiming everything comes from jet stream and other stratospheric little dense air… And the lower troposphere school where denser air masses do control what’s happening in lesser dense altitude.
Marcel Leroux in his key paper https://hacenearezkifr.files.wordpress.com/2018/05/leroux-1993c.pdf
explains what he has observed and measured.
Instead of nullschool.net especially at 500 hPa, read the Leroux paper and then take the time to go tocomment image
and observe how MPH are evolving over a year. You’ll quickly realize that polar air masses at all seasons tend to reach the tropics and are in no way limited by THE jet stream…

Reply to  TomRude
December 29, 2019 4:51 pm

re: ” there are two schools: the altitude one that seems to prevail these days, claiming everything comes from jet stream and other stratospheric little dense air… And the lower troposphere school where denser air masses do control what’s happening in lesser dense altitude.”

It does seem that most ppl “latch onto” the jet stream as some sort of controlling mechanism, whereas the material I was brought up on showed the jet to be a creature (created indirectly) of (by) interacting high and low pressure systems and their interacting fronts.

TomRude
Reply to  _Jim
December 29, 2019 9:22 pm

Leroux’s take is that the jets are a consequence of the lower tropospheric circulation. And it makes way more sense to me, especially because satellite observation of lower layers circulation does explain the appearance of the jets their development and then their demise. That’s why calling them THE jet stream is abusive by any means.
I personally like this website to monitor the jets. And it does animations to better visualize their evolution. http://squall.sfsu.edu/crws/jetstream.html

Reply to  TomRude
December 30, 2019 3:24 am

For over two decades now (gosh, has been that long now?) I’ve been making use of these folks ‘weather data’ http://weather.rap.ucar.edu and particularly, their satellite imagery webpage: http://weather.rap.ucar.edu/satellite/ and http://weather.rap.ucar.edu/upper/ (upper winds).

Observing for “divergence” in upper level wind patterns has been ‘the clue’ for up-coming severe weather outbreaks, in combination with the necessary moisture (water vapor) in the lower levels.

I think today’s “over reliance” of spotting ‘the jet’ is a product of easily created graphics that the human mind THEN places value on, whether or not that value is ‘true value’, giving the observer that warm-fuzzy feeling one gets from confidence. In reality, its a “foolie”, a step or two away from the actuality of the atmospheric physics/the dynamics of ‘fluid flow’ actually taking place. I’ve raised this point a time or two in the past, and the comment always has been ignored. I’ll take a look at Leroux’s material too, now.

WXcycles
Reply to  GeologyJim
December 30, 2019 3:45 am

IMO, you’re on the right track Jim. Over the pole the stratosphere has much more mass and molecules than over the equator. This is simply because the tropopause is at ~28,000 ft (defined by the convective humidity level that can get up to about that height and no higher over the pole).

So all above that humidity altitude level is deemed to be in the low humidity ‘stratosphere’. But the stratosphere-proper is defined by its temperature inversion which at present, over the Antarctic is at ~42,000 feet, where the temperature begins to rise again above that. That is where the polar stratosphere really begins, as the air below that T inversion is effectively just like the troposphere with less vertical motion. But there is in fact vertical motion, it’s just more organised within sinking and rising air in weak Lows and persistent weak Highs.

So from 28,000 ft to about 42,000 feet the air keeps cooling with increasing height, just like the troposphere below that alt range does. The only difference between this lower most stratosphere and troposphere under it is, (1) it’s ~1% humidity, (2) it’s even colder than the tropopause below.

Other than that potential pressure isobars and winds in the range 40,000 ft to 28,000 ft show that the lower most stratosphere readily sinks into the tropopause. In fact Highs at 39,000 ft do sink all the way from there to the high altitude icesheet just 15,000 ft below the tropopause. The Highs tend to sink in cohesive columns from just below the inversion level, all the way to the icesheet due to less convection disruption. As they do so they dump colder air into the polar- and mid-latitude Hadley Cells, cooling them.

IMO, if that sinking cooling air increases in rate, via whatever stratospheric relative cooling process near to or above the inversion, then the polar troposphere will NET cool down over several years and the growing coldness transported equatorward by the polar and then sub-tropical jetstream.

Established and fairly stable pressure systems do dominate the lower-most troposphere’s slower more organised vertical and also lateral flows, but it’s disrupted and altered by transient waves.

WXcycles
Reply to  WXcycles
December 30, 2019 5:21 pm

The last paragraph should say:

“Established and fairly stable pressure systems do dominate the lower-most STRATOSPHERE’S slower more organised vertical and also lateral flows …

ren
December 29, 2019 8:21 am

It’s worth seeing how excess ozone over North America affects the stratospheric polar vortex pattern.
https://earth.nullschool.net/#current/wind/isobaric/10hPa/orthographic=-341.96,88.89,340

Reply to  ren
December 29, 2019 10:59 am

Don’t you mean, see how ozone rides the stratospheric pattern? How does such a sparse and lofty constituent impose and sustain such large momentum on the lower atmosphere? What is the average distance between ozone molecules, how and why do they move in the various observed patterns and how does that mechanism actually work on the bulk atmosphere many miles below if ozone is driving the pattern?

I see it differently: cold air builds, expands, sinks, and ozone goes along for the ride.

This process occurs every winter from low insolation, some winters more than others.

The outlier winters known for polar vortex expansions such as this and last year, and 2013/14 can be most easily understood in terms one of two solar activity conditions:

1. long-duration solar minimum TSI, or
2. frequent deeper than solar minimum TSI drops winter from high sunspot area in winter.

At the AGU in Dec 2018 I showed this and predicted another early hard winter for 2019:

comment image (SORCE TSI w/PMOD infill 2013/14.)

The snows of the 2013/14 were horrendous and frequent. I shovelled our roof four times.

The 2013/14 larger TSI swings and high range excursions set the extreme conditions for the heavy evaporation and snowfall. The negative-going TSI set up the cold for the tropical moisture blasts that were generated by the positive-going high TSI spikes to clash with and dump heavy snows.

It seems the worst snows come from both extreme tropical and polar conditions, driven by the magnitude and duration of solar extremes.

ren
Reply to  Bob Weber
December 29, 2019 2:27 pm

Ozone sinks because the O3 ozone molecule is very heavy compared to O2 and N2. This is clearly seen as excess ozone falls into the troposphere.
comment image
https://www.cpc.ncep.noaa.gov/products/stratosphere/strat_int/
comment image
comment image

Reply to  ren
December 30, 2019 4:50 am

It sinks when its air parcel cools and sinks, taking the ozone with it. The denser ozone collects in its own boundary layer, as observed.

How can such sparse molecules impart and sustain momentum on large parcels? It’s essentially the same question asked about CO2. How can it cause the wind to blow?

ren
Reply to  Bob Weber
December 30, 2019 5:09 am

Ozone is a diamagnetic, therefore it creates waves in the geomagnetic field.
https://www.cpc.ncep.noaa.gov/products/intraseasonal/temp50anim.shtml

ren
Reply to  Bob Weber
December 30, 2019 5:13 am

In periods of low solar wind, ozone is also formed in the lower stratosphere as a result of ionization by GCR.
http://sol.spacenvironment.net/raps_ops/current_files/Cutoff.html

Reply to  Bob Weber
December 30, 2019 9:24 am

Stratospheric Intrusions are when stratospheric air dynamically decends into the troposphere and may reach the surface, bringing with it high concentrations of ozone which may be harmful to some people. Stratospheric Intrusions are identified by very low tropopause heights, low heights of the 2 potential vorticity unit (PVU) surface, very low relative and specific humidity concentrations, and high concentrations of ozone. Stratospheric Intrusions commonly follow strong cold fronts and can extend across multiple states. In satellite imagery, Stratospheric Intrusions are identified by very low moisture levels in the water vapor channels (6.2, 6.5, and 6.9 micron). Along with the dry air, Stratospheric Intrusions bring high amounts of ozone into the tropospheric column and possibly near the surface. This may be harmful to some people with breathing impairments. Stratospheric Intrusions are more common in the winter/spring months and are more frequent during La Nina periods.

source

Ozone is a rider on the storm…

ren
Reply to  Bob Weber
December 31, 2019 6:30 am
Reply to  ren
December 31, 2019 6:34 am

re: “I do not agree with you.”

How can you disagree with a question?

ren
Reply to  Bob Weber
December 31, 2019 7:09 am

The distribution of ozone in the stratosphere has a decisive impact on winter circulation.
comment image

ren
Reply to  Bob Weber
December 29, 2019 11:20 pm

In winter, the gravitational wave moves from the mesosphere to the lower atmosphere layers.
comment image

Johann Wundersamer
January 8, 2020 10:20 am

“The US and Australia have media that balance the debate, but NZ has none. We are now subjected to daily sermons with no means of reply.”

Michael Carter, you ALREADY replied.

Who doesn’t want to hear Must feel: if NZ won’t read NZ gets told another way.

Reply to  Johann Wundersamer
January 8, 2020 10:29 am

re: “The US and Australia have media that balance the debate”

Ha! That’s funny … coming back from “humour hour” (happy hour to some types) already?

Johann Wundersamer
January 9, 2020 12:54 am

_Jim January 8, 2020 at 10:29 am

re: “The US and Australia have media that balance the debate”

Ha! That’s funny … coming back from “humour hour” (happy hour to some types) already?
____________________________________

Michael Carter December 28, 2019 at 11:46 am

The 2 MSM companies that control 80% of news publications in New Zealand are making big over a warm marine blob centered ~ 2000 km off our east coast. They then go on about tropical fish having been observed further Sth than ever and publish comments from the most extreme alarmist scientist in NZ. They make no mention of the cold trend surrounding the country.

comment image

This cold zone has been creeping north and intensifying over the last month. Balanced journalism would surely discuss both phenomenon.

The US and Australia have media that balance the debate,

but NZ has none. We are now subjected to daily sermons with no means of reply.

M

____________________________________

_Jim, wrong answer. Here’s not the post office of Michael Carter.

What’s loose with you. That’s funny … coming back from “humour hour” (happy hour to some types) already?

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