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Pmt111500

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polar vortex - where?
« on: December 27, 2013, 01:30:03 PM »
This is just a question based on the noaa upper level wind re-analysis products in here: http://www.esrl.noaa.gov/psd/map/images/rnl/250wnd_07b.rnl.html

Is my interpretation correct, is the polar vortex in two pieces currently? Could someone point me to a North Pole centered plot for upper level winds?  Also in the image it seems like the subtropical jets cross the equator in tropical eastern Pacific, which might be of common occurrence, I've not followed these well at all.

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SATire

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Re: polar vortex - where?
« Reply #1 on: December 27, 2013, 02:09:35 PM »
I think Werther has the answer for you here: https://forum.arctic-sea-ice.net/index.php/topic,67.msg18085.html#msg18085
and he is drawing the picture you are looking for - maybe you should ask him.

werther

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Re: polar vortex - where?
« Reply #2 on: December 27, 2013, 03:13:14 PM »
Pmt111500,
Get this from the Daily Composites through ‘region = NHemisphere’ and ‘Choose projection = NH Polar Stereographic’:


I wrote about the peculiarities  of the weather patterns this fall over here, as SATire has posted above: " Consequences / Re: Arctic Amplification and Extreme Weather « on: December 22, 2013, 01:39:48 PM »", as well as on neven’s blog thread  ‘Arctic warming -> extreme weather debate’, where Neven posted a CRWS Jetstream graph for 2212. It showed circulation around the complete cut-off of the extended ridge over central Europe to Svalbard. This filled the dark, lower troposphere over the Pole with anomalous warm and moist air.

The Polar Vortex is under pressure, both from the tropospheric ridging and from a tendency towards Sudden Stratospheric Warming high up. It is interesting to see whether this will lead to a pronounced split that can produce a WACC pattern like we have seen regularly through the last four or five winters. For N America it is already quite clear.
« Last Edit: December 29, 2013, 10:25:44 PM by werther »

Neven

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Re: polar vortex - where?
« Reply #3 on: December 27, 2013, 07:23:03 PM »
Or have a look at this and try to keep your pants on.

Does the difference between the Polar Vortex and Jet Stream have to do with heights? Sorry, too lazy to look it up (although I did before, but forgot everything).
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wili

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Re: polar vortex - where?
« Reply #4 on: December 27, 2013, 07:46:35 PM »
This is a case of the blind leading the far-sighted, but iirc the tropopause slopes down toward the poles, so I would assume that the polar vortex has a lower altitude than the mid-latitude jet stream.

Are people saying that the polar vortex is already collapsing? Have there been a lot of Sudden Stratospheric Warming events lately?

And does the switch to the Warm Arctic Cold Continents pattern (http://neven1.typepad.com/blog/2012/03/wacc-overview.html --I had to track this down to figure out the acronym: at first all I could find for WACC was Weighted-Average Cost of Capital and World Alliance for Christian Communication, and I had a sneaking suspicion that those weren't right) mean that we are going to continue to have cold winters in Minnesota for the foreseeable future?  :) :-\
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

jdallen

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Re: polar vortex - where?
« Reply #5 on: December 27, 2013, 08:03:41 PM »
This is a case of the blind leading the far-sighted, but iirc the tropopause slopes down toward the poles, so I would assume that the polar vortex has a lower altitude than the mid-latitude jet stream.

Are people saying that the polar vortex is already collapsing? Have there been a lot of Sudden Stratospheric Warming events lately?

And does the switch to the Warm Arctic Cold Continents pattern (http://neven1.typepad.com/blog/2012/03/wacc-overview.html --I had to track this down to figure out the acronym: at first all I could find for WACC was Weighted-Average Cost of Capital and World Alliance for Christian Communication, and I had a sneaking suspicion that those weren't right) mean that we are going to continue to have cold winters in Minnesota for the foreseeable future?  :) :-\

Probably, but the pattern does appear to be shifting in the direction of WACC.
http://www.esrl.noaa.gov/psd/map/images/fnl/sfctmp_01.fnl.html

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wili

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Re: polar vortex - where?
« Reply #6 on: December 27, 2013, 09:36:56 PM »
Thanks, jd. That's a pretty stunning contrast: Most of the Arctic Ocean above -25 C while large portions of northern Canada and Siberia are below -30 (if I'm reading this correctly).

Is that because warmth is getting out from the water through cracks in the ice up into the atmosphere? Or are there other dynamics--more water vapor above the ice pack acting as local ghg? Do we know how unusual of a pattern this is for this time of year historically?
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

jdallen

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Re: polar vortex - where?
« Reply #7 on: December 27, 2013, 10:57:22 PM »
Thanks, jd. That's a pretty stunning contrast: Most of the Arctic Ocean above -25 C while large portions of northern Canada and Siberia are below -30 (if I'm reading this correctly).

Is that because warmth is getting out from the water through cracks in the ice up into the atmosphere? Or are there other dynamics--more water vapor above the ice pack acting as local ghg? Do we know how unusual of a pattern this is for this time of year historically?

I'm not sure about the historic pattern; I'll let others comment intelligently there. This year  from what I've seen, the temperatures appear to be driven primarily by persistent flow of warmer, moister air out of low latitudes, roughly following the Gulf Stream into the Barents on the Atlantic side, and in the Pacific,  following eastern coastal Asia, cutting north between/from Eastern Siberia to Western Alaska.  This appears to be driving increased snowfall in some locations, and driving some of the continental arctic breakouts across N America.  I am waiting with a mix of interest and anxiety over what the temps do to the refreeze.
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werther

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Re: polar vortex - where?
« Reply #8 on: December 27, 2013, 11:02:51 PM »
Hi Neven,
yes, that new wind asset is marvellous! If you hit 850hPa you will start seeing the contours of the main Polar Vortex over Foxe Basin. The cut-off ridge, while still over the Pole in the mid-troposphere, now has contributed to a high pressure system over the CAB close to the Chukchi/Beaufort sector.

As Wili posted, the tropopause slopes down from the mid-latitudes to the Pole. But that slope is complicated through the ever changing lobes formed by the Rossby waves. One of these, while based over eastern Europe, was exceptionally extended, creating the cut-off ridge. This propelled some large amounts of energy into the Arctic. Most vivid on 850Mb, 20dC temp anomaly three days ago.
To be fair, I haven’t seen an indication yet that 10Mb temps in the stratosphere are on the rise over the Arctic. But the process should be starting in mid-Asia, as I’ve seen announced on The Weather Centre.

What does keep me thinking and checking, is the slow pace to the same temp anomalies over the Arctic as filed in the ’07-’12 period. The cold fall is now nearly levelled by ‘warm’ December weather. The almost perfect round-up of vortex and cold over North America is striking, as goes too for large positive anomalies over Eurasia and the Arctic Ocean. And the wave patterns…

My thinking shifts from associations with the rapidly rising CO2-content, ocean-atmosphere coupling and maybe not that much pronounced contribution by large amounts of open water last fall. I don’t see a pause. I see the random, mosaic-like pattern in which AGW is shaping up and how our expectations go wrong  each new season.
This isn’t a linear, logical process. But, OK, winter still has a long time to go.

jdallen

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Re: polar vortex - where?
« Reply #9 on: December 27, 2013, 11:50:05 PM »
And to add some additional thought to the discussion, let's add these:
http://www.esrl.noaa.gov/psd/map/images/fnl/sfctmpmer_30.fnl.html
And the relevant anomalies...
http://www.esrl.noaa.gov/psd/map/images/fnl/sfctmpmer_30a.fnl.html

I think they reflect pretty clearly how the changes in circulation are driving energy into the Arctic, and are creating breakouts as colder drier air is displaced.
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ChrisReynolds

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Re: polar vortex - where?
« Reply #10 on: December 29, 2013, 07:26:05 PM »
JD Allen,

It's a positive AO index pattern with a jetstream heading over the UK bringing us a succession of low pressure - then carrying on towards northern Europe and Scandinavia, with flow up into the South West Barents Sea.

The polar vortex is strong above 100mb weak below that.
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/hgt.shtml

500mb GPH shows anomalous low over the UK and NW Europe.
http://www.esrl.noaa.gov/psd/map/images/fnl/500z_07b.fnl.html
Following the 515 isopleth across the UK (bright purple) shows it going up towards Scandinavia and the Arctic, this is the rough track of the jet stream.

SFSU shows the track of the jet.
http://virga.sfsu.edu/archive/jetstream/jetstream_norhem/1312/13122906_jetstream_norhem.gif

50mb wind shows the Polar Vortex as one vortex from Greenland over to Siberia.
http://www.esrl.noaa.gov/psd/map/images/fnl/50wnd_01b.fnl.html
With surrounding vortex wall (greens) across NH continents, the upward mass towards Bering shows the location of the vortex centre towards the eastern (Atlantic) sector of the Arctic.

For what it's worth, I've recently emailed a few people to give my winter forecast, this is for the UK.

Quote
I've finally got round to checking out the prospects for this Winter.

Dr Judah Cohen's method produces confusing results, he is reported as saying he expects a generally positive Arctic Oscillation (AO) index. Current forecasts of the AO suggest it will go negative shortly, that happens. But the cross section of the polar vortex suggests that so far the vortex has been consistently strong, which suggests a positive AO index.

In 2009/10 the polar vortex was weak and even reversed and the AO index very negative, a negative AO index has also been a feature of other recent winters, such as last winter. March 2012 was the coldest March in the entire Central England Temperature record.

However aside from the risk of random cold snaps there is a caveat, sea ice in the Barents Sea is lower than average due to warm influx from the Atlantic Ocean. This has been associated in a modelling study with cold outbreaks into Europe and was the cause of the 31/1/12 to 7/2/12 cold outbreak in Europe, in my opinion.

So I expect that the winter will be generally around average temperatures and dominated by low pressures coming off the Atlantic, with little risk of largescale easterly flow from Eurasia bringing prolonged unusually cold weather and snow. However there remains the chance of short cold snaps with snow and/or severely sub zero temperatures.

jdallen

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Re: polar vortex - where?
« Reply #11 on: December 29, 2013, 09:38:32 PM »
@Chris - thanks for the observation.  I've been watching circulation with interest but am strictly amateur in my understanding of geopotential heights and anomalies. I've been following both the 300 mob jet stream map and tinkering with the earth.nullschool.net wind map.

I've been struck by the long continuous flows from below 30N sweeping through 45 degrees or more of latitude into the high arctic. It seems to have a direct relation to the reported temperature anomalies I have been following.

IJIS extent is lagging well behind average.  I wonder if volume increase is tapering off similarly.  It will be interesting to see if the heat pump persists through winter.

Is it possible a smaller polar vortex may prevent thickening of ice in the peripheral arctic seas?  All to fascinating.
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ChrisReynolds

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Re: polar vortex - where?
« Reply #12 on: December 30, 2013, 11:19:35 AM »
JD Allen,

There's a paper on the influence of the AO on sea ice, it's summarised here:
http://seaice.apl.washington.edu/AO/

During the 1990s positive index AO lead to a stronger transpolar drift and increased Fram outflow. The stronger transpolar drift formed more ice in East Siberian and Laptev Seas, but the increased Fram outflow would have lead to more export of thicker multi year ice.

NCEP/NCAR meridional wind (north/south wind component) for November shows a strong southerly flow through the Fram Strait,Link - give the link a while to generate the plot. While over the siberian to pole part of the pack net flow is poleward.

Current HYCOM shows a strong flow from Siberia and through Fram.
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticicespddrfnowcast.gif
Shame we can't get monthly averages on that. However a paper by Zhang shows that the correlation between wind speed and ice motion has increased as the pack has thinned. EDIT - in that paper they describe current conditions as being in free flow, with correlation of well over 0.85.

So the main role for the polar vortex this winter may be in Fram export increasing, and more ice formation off Siberia. As the first link in this reply shows - that will cause thinner ice off Siberia and that in turn will warm the atmosphere reducing the thickening of ice.

The end result may mean that much of the volume increase by last September may not make it through to next melt season - which would mean I'd be wrong and Crandles right.

One word of caution with regards area/extent as it nears maximum. The maximum is set by conditions in the peripheral seas outside the Arctic, at this time only the Atlantic sector plays a role in that in terms of ice within the Arctic. However conditions at minimum within the Arctic are related to both weather through the melt season and sea ice conditions within the Arctic. You can in theory have a high extent/area at maximum followed by a record low at minimum because the two are dependent upon processes thousands of miles apart.

Is that a complete enough answer?  ;)

jdallen

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Re: polar vortex - where?
« Reply #13 on: December 30, 2013, 05:47:12 PM »
Quite sufficient Chris. 

I'm not sure the Fram even at its most efficient will be a key factor.  At its most efficient, with ice moving at 3km/hr, outflow would be less than 30k/km2 a day.  The loss of MYI is significant, but last year, against my presumptions about it, the flow had less impact on the final minimum than I thought it would.

The overall increase in temperature and thinner ice at the end of winter will be more significant in the long run.
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ChrisReynolds

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Re: polar vortex - where?
« Reply #14 on: December 31, 2013, 03:28:10 PM »
JD Allen,

I agree.

idunno

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Re: polar vortex - where?
« Reply #15 on: December 31, 2013, 07:39:36 PM »
A love heart for all and sundry, this New Year...

http://earth.nullschool.net/#current/wind/isobaric/70hPa/orthographic=-2.67,89.89,270

Let's hope its a good one, without any fear.


Neven

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Re: polar vortex - where?
« Reply #16 on: December 31, 2013, 10:32:26 PM »
Aaahhh, so romantic!  :-*
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idunno

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Re: polar vortex - where?
« Reply #17 on: January 05, 2014, 03:24:47 AM »
The polar vortex -where?

Milwaukee, according to Ryan Maue of WeatherBell...

http://www.theguardian.com/world/2014/jan/04/us-snowstorm-dead-dangerous-wind-cold

Also linked this on the Weird Weather thread.

Pmt111500

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Re: polar vortex - where?
« Reply #18 on: January 05, 2014, 06:49:01 AM »
The polar vortex -where?

Milwaukee, according to Ryan Maue of WeatherBell...


Thanks! :-D . Like Wayne said over in the blog "Not enough winter to go around", so it's good to know it's somewhere :-)
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wili

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Re: polar vortex - where?
« Reply #19 on: January 05, 2014, 07:16:57 AM »
So, I did a google scholar search on "Ferrel Cell" and one of the more interesting finds was this recent dissertation: What is Driving Changes in the Tropospheric Circulation? New Insights from Simplified Models


Tando​n_columbia​_0054D_113​76.pdf

Quote
idealized thermal forcings mimicking increases in stratospheric water vapor produce poleward expansion of the Hadley cells (HCs) and poleward shifts of the midlatitude jets. Quantitatively, the circulation responses are comparable to those produced by increased well-mixed greenhouse gases. This suggests that stratospheric water vapor may be a significant contribution to past and projected changes in the tropospheric circulation.

The second part of this thesis focuses on the response to idealized thermal forcings in the troposphere. It is found that zonally uniform warming confined to a narrow region around the equator produces contraction of the HCs and equatorward shifts of the midlatitude jets.

Forcings with wider meridional extent produce the opposite effect: HC expansion and poleward shifts of the jets. If the forcing is confined to the midlatitudes, the amount of HC expansion is more than three times that of a forcing of comparable amplitude that is spread over the tropics. This finding may be relevant to recently observed trends of amplified warming in the midlatitudes. Furthermore, a simple diffusive model is constructed to explain the sensitivity of the circulation response to the meridional structure of the thermal forcing.

So is this what we are seeing happening? Is the jet stream moving so far north that it is merging with the polar vortex (that then moves south, bringing Arctic air further south than it would otherwise)?
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

jdallen

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Re: polar vortex - where?
« Reply #20 on: January 05, 2014, 09:38:30 AM »
So is this what we are seeing happening? Is the jet stream moving so far north that it is merging with the polar vortex (that then moves south, bringing Arctic air further south than it would otherwise)?

I'm not sure, but what we are seeing looks astonishing.

http://squall.sfsu.edu/scripts/nhemjetstream_model.html

Check the jetstream on January 2nd.  There is a *6000 KM Long* North/South jet running from the Canadian arctic all the way down to the lower Mississippi valley.

Looking at our new toy ( http://earth.nullschool.net/#current/wind/isobaric/500hPa/orthographic=-98.21,62.25,350 ), 500MB circulation north of 60 degrees of latitude has disintegrated into a half dozen small vortices, both low and high pressure.

Has anyone seen anything at all remotely like this?!
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Shared Humanity

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Re: polar vortex - where?
« Reply #21 on: January 05, 2014, 06:47:58 PM »
So is this what we are seeing happening? Is the jet stream moving so far north that it is merging with the polar vortex (that then moves south, bringing Arctic air further south than it would otherwise)?

I'm not sure, but what we are seeing looks astonishing.

http://squall.sfsu.edu/scripts/nhemjetstream_model.html

Check the jetstream on January 2nd.  There is a *6000 KM Long* North/South jet running from the Canadian arctic all the way down to the lower Mississippi valley.

Looking at our new toy ( http://earth.nullschool.net/#current/wind/isobaric/500hPa/orthographic=-98.21,62.25,350 ), 500MB circulation north of 60 degrees of latitude has disintegrated into a half dozen small vortices, both low and high pressure.

Has anyone seen anything at all remotely like this?!

The 2nd cold  wave  that has just hit (1/5) the  midsection of North America has an even more spectacular North/South  jet and that persistent high pressure ridge over the  North Pacific seems to be contributing.

Shared Humanity

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Re: polar vortex - where?
« Reply #22 on: January 05, 2014, 06:50:59 PM »
In that 2nd animation, are those scattered high pressures all over the Arctic?

Where is the polar vortex?

idunno

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Re: polar vortex - where?
« Reply #23 on: January 06, 2014, 02:04:56 AM »
Idunno if this helps much, but I loved the headline...

http://scienceblogs.com/gregladen/2014/01/05/go-home-arctic-youre-drunk/

Looking through the pretty pictures which I don't understand, it seems to me that at this height...

http://earth.nullschool.net/#current/wind/isobaric/70hPa/orthographic=-2.67,89.89,270

...70hPa seems the best guide to the basic pattern, an extraordinary elongation of the "eye" of the polar vortex, which is most evidently affecting the US.

Is there any potential for the eye to split in two, perhaps? It sorta looks that way to me. If the winds flowing from Siberia turn towards Franz Josef land, that makes a circle, leaving another circle, centred on Greenland.  Altogether, a binocular polar vortex?

I'm seeing double. Get to bed, idunno, you're drunk.

jdallen

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Re: polar vortex - where?
« Reply #24 on: January 06, 2014, 09:34:46 AM »
70pa is near the top of the troposphere and has limited impact on weather short term.  250 pa down is where we want to keep our attention.
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werther

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Re: polar vortex - where?
« Reply #25 on: January 06, 2014, 11:00:22 AM »
Well, yeah... as I interpret, 250 Mb, app. on 9000 m ASL, top of troposphere over the Arctic, the right place to look for the Polar Jet marking the boundary between Ferrell and Polar cells.

Idunno shows 70Mb, lower stratosphere, the Polar Night Jet on app. 24 km ASL, which is distinct from the 250Mb Polar Jet, as it circles the stratospheric Polar Vortex.
Which is under siege.
When it splits, the effects of the SSW propagate down into the Polar Cell. So while 250Mb is the place to look for weather sequence, what comes down from above will be as interesting!

Atomant

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Re: polar vortex - where?
« Reply #26 on: January 06, 2014, 05:56:50 PM »
Tropic to Arctic flow possibly altered possibly by northern hemisphere high pressures intensifying.

Paper here: http://www.nature.com/ngeo/journal/v5/n11/full/ngeo1590.html

Article here: http://summitcountyvoice.com/2012/10/09/global-warming-may-intensify-subtropical-high-pressure-systems-that-shape-northern-hemisphere-weather-patterns/

Pacific high so strong that split the JT a couple of times in December.

Shared Humanity

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Re: polar vortex - where?
« Reply #27 on: January 06, 2014, 09:28:55 PM »
Tropic to Arctic flow possibly altered possibly by northern hemisphere high pressures intensifying.

Paper here: http://www.nature.com/ngeo/journal/v5/n11/full/ngeo1590.html

Article here: http://summitcountyvoice.com/2012/10/09/global-warming-may-intensify-subtropical-high-pressure-systems-that-shape-northern-hemisphere-weather-patterns/

Pacific high so strong that split the JT a couple of times in December.

And the intensifying North Pacific high pressures are contributing to a persistent and intensifying drought across the Southwestern U.S. Precipitation has been below normal for the past decade. We are, all kidding aside, running out of water in one of the fastest growing regions of the  U.S.

ChrisReynolds

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Re: polar vortex - where?
« Reply #28 on: January 07, 2014, 07:27:52 PM »
70pa is near the top of the troposphere and has limited impact on weather short term.  250 pa down is where we want to keep our attention.

Not if you're looking for the Polar Vortex.

From PSD map room.
http://www.esrl.noaa.gov/psd/map/clim/glbcir.shtml

1 day 50mb winds (stratosphere) show a split vortex over the Taymyr Peninsular (Siberia) and Baffin Island (Canada).
http://www.esrl.noaa.gov/psd/map/images/fnl/50wnd_01b.fnl.html

CPC still shows that the vortex is weak below 100mb, strong above:
http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/hgt.shtml

I've uploaded a plot from NCEP/NCAR showing the twin vortices as of the 5th, the most recent day available on that system.


Pmt111500

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Re: polar vortex - where?
« Reply #29 on: January 24, 2014, 03:13:44 AM »
robertscribbler reports: http://robertscribbler.wordpress.com/2014/01/23/arctic-heat-wave-to-rip-polar-vortex-in-half-shatter-alaskas-all-time-record-high-for-january/

The north Pacific discharging heat to arctic (through atmosphere though, mind you) with the north Atlantic accompanying producing a situation looking much like warm arctic/cold continents.
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jdallen

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Re: polar vortex - where?
« Reply #30 on: January 24, 2014, 07:54:07 AM »
robertscribbler reports:
The north Pacific discharging heat to arctic (through atmosphere though, mind you) with the north Atlantic accompanying producing a situation looking much like warm arctic/cold continents.

I've been watching that flow through the central arctic for the best part of the last two months.  There hasn't necessarily been a clear split in low-level or high level flow throughout that time, but temperatures have been *consistently* 3-5C warmer along a line which runs from Svalbard to NW Alaska just east of Bering strait.
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SATire

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Re: polar vortex - where?
« Reply #31 on: February 07, 2014, 11:10:02 AM »
looks like a nice stratospheric dipole today at 10Pa: http://earth.nullschool.net/#current/wind/isobaric/10hPa/orthographic=-7.55,79.00,270

I am not sure if you may call the 2 small vortices (over Ural and over Hudson Strait) "polar vortex"- probably not.

edit: Just attached that picture, since that dipole will be gone in some days...
« Last Edit: February 07, 2014, 01:52:26 PM by SATire »

werther

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Re: polar vortex - where?
« Reply #32 on: February 07, 2014, 12:21:47 PM »
Hi SATire,

10hPa/Mb is definitely in the stratosphere. It shows the polar night jet, which is well displaced/deformed from its usual position Baffin Island-Taymir Peninsula.

I checked 70hPa, which I think is lower stratosphere just above the tropopause, still showing the same properties. Big positive pressure anomaly above the East Sib Sea.


Pmt111500

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Re: polar vortex - where?
« Reply #33 on: February 07, 2014, 02:23:24 PM »
on lower levels 250mb to 700mb it shows a clockwise jet over the pressure anomaly, I'm tempted to say this is an incursion of subpolar or temperate air slowly cooling down, kind of opposite to what happened in American midwest recently.
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ChrisReynolds

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Re: polar vortex - where?
« Reply #34 on: February 07, 2014, 05:58:30 PM »
Hi SATire,

10hPa/Mb is definitely in the stratosphere. It shows the polar night jet, which is well displaced/deformed from its usual position Baffin Island-Taymir Peninsula.

I checked 70hPa, which I think is lower stratosphere just above the tropopause, still showing the same properties. Big positive pressure anomaly above the East Sib Sea.

Is that the usual position, or just the position this winter? I attach a plot of GPH from NCEP/NCAR showing the climatology.

FWIW I'm linking this odd dumbell vortex to the weird winter we're having in the UK.

werther

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Re: polar vortex - where?
« Reply #35 on: February 07, 2014, 11:03:07 PM »
Let's put it this way... on 70Mb the polar night vortex is displaced enough to support an extreme energy 'limes convergens', stretching from Newfoundland to Ireland. All narrow temp-energy contrasts in the upper ocean, troposphere and stratosphere seem to get together right there,
In the climo, it would be a more divergent corridor leading just N of Scotland into the Norwegian Sea, where disturbances would loose their energy in a less explosive manner....

The enhanced part is, that this is the format for all NH winter 1 Oct-4 Feb....

ChrisReynolds

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Re: polar vortex - where?
« Reply #36 on: February 08, 2014, 08:21:08 PM »
Pretty close to what I've been thinking.

The normal winter track with a positive AO is across the north of Scotland and over to Scandinavia. This winter it's been further south leading to the south of the UK and south west getting hammered - flooding has been a major feature of this winter in the UK.

A major issue being that Scotland has adapted to such weather and is less populated, so it is their norm. Shift the norm to somewhere not used to the succesions of lows we've seen this winter and it creates havoc.

I was going to blog today on this dumbbell pattern in the polar stratosphere being the cause of the UK's winter storms. But the PIOMAS issue got in the way.

ChrisReynolds

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Re: polar vortex - where?
« Reply #37 on: February 08, 2014, 09:11:17 PM »
Just been lookin at NCEP/NCAR - my suspicion is wrong, there's no linkage because we've had similar strato set ups in January without such weather in the UK. For example Jan 2013 had an even stronger dumbell, yet we had easterly winds with cold and a storm track (to the south IIRC).

werther

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Re: polar vortex - where?
« Reply #38 on: February 08, 2014, 11:17:05 PM »
Hi Chris, I see you’ve done some NCEP/NCAR selection on Jan ’13. But consider this anomaly:
[/URL]
This supports suggesting a vicious track for explosive lows right into Somerset.

werther

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Re: polar vortex - where?
« Reply #39 on: February 08, 2014, 11:25:05 PM »
And on 70Mb the dumbbell you mention for Jan ’13 left a lot of room for an extreme positive anomaly on 70Mb.



I remember well how that turned 10 Jan days into skating enjoyment in Holland!

werther

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Re: polar vortex - where?
« Reply #40 on: February 08, 2014, 11:41:12 PM »
I like how Chris describes landscapes /people to be adjusted to certain long-term climatic patterns. What I'd suggest to add, is the double kick when another locale is hit for an anomalous long period.
In the case of Somerset (to focus on a County I visited and loved), consider how energy contrast in the swath of ocean originating near Cape Hatteras up to Land's End is way more productive than a track Cape Race-Orkneys.
It's not that this track has't occurred earlier in the past. It's the recurrent pattern.
Just like the huge ridge in the NE Pacific depriving California from winter precipitation...

Apocalypse4Real

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Re: polar vortex - where?
« Reply #41 on: February 09, 2014, 01:39:14 AM »
I decided to dissect the vortex and jet stream this afternoon, from 10 hpa/mb down to 1000 hpa/mb. It reveals a meandering mess underneath the bi-polar flow at 10 hpa/mb. The results are on my blog:

http://a4rglobalmethanetracking.blogspot.com/




jdallen

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Re: polar vortex - where?
« Reply #42 on: February 09, 2014, 08:29:43 AM »
I decided to dissect the vortex and jet stream this afternoon, from 10 hpa/mb down to 1000 hpa/mb. It reveals a meandering mess underneath the bi-polar flow at 10 hpa/mb. The results are on my blog:

A4R, I think the operative word here is *Turbulence*.

250MB and below the general impression I have of the northern hemisphere matches that word pretty closely.
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ChrisReynolds

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Re: polar vortex - where?
« Reply #43 on: February 09, 2014, 11:28:38 AM »
Werther,

I've just realised that I downloaded 10mb GPH. Which is rather too high. I'm not going to look at this stuff today - need time off after PIOMAS V2.1 stuff yesterdat and the day before. But I'll have another look at what you're saying using data lower down in the stratosphere.

jdallen

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Re: polar vortex - where?
« Reply #44 on: February 09, 2014, 12:53:46 PM »
Werther,

I've just realised that I downloaded 10mb GPH. Which is rather too high. I'm not going to look at this stuff today - need time off after PIOMAS V2.1 stuff yesterdat and the day before. But I'll have another look at what you're saying using data lower down in the stratosphere.
That said, the northern Pacific high appears to have broken... for the moment.  Bets on how long before it reorganizes itself and reappears?
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Apocalypse4Real

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Re: polar vortex - where?
« Reply #45 on: February 09, 2014, 05:06:52 PM »
Seems the UK MET has finally decided to issue a report on the extreme UK weather and causes. I have posted on this at http://a4rglobalmethanetracking.blogspot.com/

Dame Julia Slingo, the MET chief scientist made remarks about the current extremes to the media, including "...all the evidence suggests there is a link to climate change,"....

"There is no evidence to counter the basic premise that a warmer world will lead to more intense daily and hourly rain events."

The report discusses the jet stream and stratospheric polar vortex. It is found at:

http://www.metoffice.gov.uk/media/pdf/n/i/Recent_Storms_Briefing_Final_07023.pdf


Shared Humanity

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Re: polar vortex - where?
« Reply #46 on: February 09, 2014, 06:22:46 PM »
A4R....thanks for the Met link......very good read.

Apocalypse4Real

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Re: polar vortex - where?
« Reply #47 on: February 16, 2014, 04:15:53 AM »
With Jennifer Francis's paper at the AAAS in regard to increasing Rossby Waves and stuck jet stream patterns, I updated what I had posted on the jet stream by mb layer.

http://a4rglobalmethanetracking.blogspot.com/2014/02/meandering-jet-streams-jennifer-francis.html

wili

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Re: polar vortex - where?
« Reply #48 on: February 16, 2014, 04:57:19 AM »
I put this on another thread, but it is more appropriate here:

I just noticed that, at the 10 hPa level, the polar vortex has now split in two.

http://earth.nullschool.net/#current/wind/isobaric/10hPa/orthographic=-94.05,77.28,279

Is this unusual? Unprecedented? What does it forebode?

At the 70 hPa, it is nearly in two, with a very odd configuration:

http://earth.nullschool.net/#current/wind/isobaric/70hPa/orthographic=-94.05,77.28,279
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Pmt111500

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Re: polar vortex - where?
« Reply #49 on: February 16, 2014, 06:14:15 AM »
the reality of the tropospheric jetstreams (150-250mBar) is truly often far from the idealized 2-jet situation commonly displayed in textbooks. tried to track the fastest winds speeds in the current earth wind map (snapshot of http://earth.nullschool.net/#current/wind/isobaric/250hPa/orthographic=-94.05,77.28,279) and it looks like there are 1-3 streams of jet wind streams looking from the equator to the pole - one might state that the intermediate one is some sort of combo from the subtropical jet (on the edges) and the polar jet (the northernmost lobes), I presume.  More proper interpretation could be that the subtropical jet splits near Japan coast and travels all the way to near Sochi, looking at the temperatures beneath the line.

(modified a bit later) tried to draw the approximate routes of the jet streams to the daily temperature map from here:
http://www.esrl.noaa.gov/psd/map/images/rnl/sfctmpmer_01.rnl.html
(at first it might be interpreted approximately tha +20C-subtropical jet, +5 to +10C-split subtropical jet and -20C-polar jet , but there are some notable exeptions , such as north atlantic and arctic ocean.)
« Last Edit: February 16, 2014, 07:19:04 AM by Pmt111500 »
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