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Stratosphere and Polar Vortex Watch


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Some useful tropospheric developments upcoming which are likely to have stratospheric impacts towards the end of November and more particularly into December. A strong convectively coupled tropic

so after many days the GFS & FNMOC & canadian finally now follow the Euro with 44 out 64 Members with a split at day 9- The ECM is day 8. We will call it - SSW & Split for 1st Ja

For all that watch the zonal winds. Let me urge you to look at the geopotential heights more. At least as far as weakening/strengthening trends go. Because as the polar vortex cries for help, you migh

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11 minutes ago, Allseasons-si said:

Blimey.

 

What does this mean though for an amateur perspective? With some of the posts and models predictions ive seen in this thread, it sounds like we are in an unknown territory with this unusual ssw. It sounds like it could make a major inpact on the northern hemisphere

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16 hours ago, Quicksilver1989 said:

Sorry if this isn't suitable for the thread but SSW events are a relatively new and rapidly developing area of science in weather forecasting. The potential for these to affect the UK climate are clear from the SSW warming event that occurred last year.

The first time I remember it really being talked about was the early February 2009 easterly. My knowledge on this particular branch of meteorology is lacking compared to the more experienced members. Could someone post a beginners guide to a strat event, how they occur, what the charts represent and how it manifests into increased chances of cold spells across the North Hemisphere.

Admittedly all I know is that they reverse winds in the upper atmosphere which eventually propogate down to the surface. It would be useful I think if a knowledgeable poster did a guide with some basic images that we can go back to if one hasn't been done already (a sticky thread perhaps). A textbook SSW event from its beginnings to its finish, me and many newbies to this area would highly appreciate it ?.

Thanks ? 

QS, have a read and watch the video on the following link, I think it may help to provide what you are seeking 

https://www.metoffice.gov.uk/learning/wind/sudden-stratospheric-warming

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10 hours ago, Allseasons-si said:

Blimey.

 

Great discussion, on this poleward shift. Only one person I know who could unravel it and he has now replied. Top work from Anthony as ever.

In short a sheared vortex filament wraps under the high..

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11 hours ago, lorenzo said:

 

output_kJ9FM8.thumb.gif.d1aa8641d226b752f879a50f2c626211.gif

Great to get HD Strat TV for Xmas, and even better for the atmosphere to put on anything better than what will be on normal TV..!

 

Those GEOS charts are a bit SD, for HD try the animations (up to 10mb, 240h on 00z 120h on 12z) here - https://fluid.nccs.nasa.gov/wxmaps/?region=nps

Update on minimum zonal winds from last 18z and 00z runs -

GFS -2.0, +3.7 m/s

Para +6.4, +10.8 m/s

Wow!

 

 

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2 minutes ago, Interitus said:

Those GEOS charts are a bit SD, for HD try the animations (up to 10mb, 240h on 00z 120h on 12z) here - https://fluid.nccs.nasa.gov/wxmaps/?region=nps

Update on minimum zonal winds from last 18z and 00z runs -

GFS -2.0, +3.7 m/s

Para +6.4, +10.8 m/s

Wow!

 

 

hmmm going the wrong way.

Not saying it wont change on subsequent runs but GFS hasn't really bought into it at all. (the split and reversal of winds)

Hope GLOSEA has this nailed if I'm honest as could end up being the winter of so near yet so far.

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2 hours ago, lorenzo said:

Great discussion, on this poleward shift. Only one person I know who could unravel it and he has now replied. Top work from Anthony as ever.

In short a sheared vortex filament wraps under the high..

Will have to have a look at this, however not sure this is the whole explanation - +ve u anomalies in the subtropics would lead to an expanded anomaly region, but the hovmoller shows that the QBO anomaly signature shifts northwards with a reduction over the equator.

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Tropical cycle (MJO eastward propagation) isn't looking likely to be fast enough to tip the balance in time for the late Dec SSW so this will come down to the dynamical modelling of the stratosphere. It will reveal a lot about the capabilities the various models have.

Early Jan still open for a split even if the Dec event is only a displacement, with this being driven by the momentum transport associated with the tropical cycle. Currently GFS/GEFS and ECM/EPS are struggling severely with that. What's new? I hear you ask! ?

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16 hours ago, lorenzo said:

???

output_kJ9FM8.thumb.gif.d1aa8641d226b752f879a50f2c626211.gif

Great to get HD Strat TV for Xmas, and even better for the atmosphere to put on anything better than what will be on normal TV..!

output_m17SpQ.thumb.gif.323f351203d2af1a58feb7c854379b37.gif

TBH the tropical developments given the parlous state of the UTLS this season would have been enough to create notable interest. Factor in tonight's ECM and it's Merry Xmas for all us geeks.

Those Stratopsheric warming charts are more entertaining to watch than even looking at YouTube videos of people mowing their lawns! 

Sure is some hammering that upper Vortex is getting.

Triple fingers crossed this warming will indeed lead to something wonderous and white for the snow fans. (Even if it may mean a bit of waiting and just hoping the cold fans end up being in the favourable area for this evolving pattern). ??

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Apologies, I'm struggling to post pics from my PC...but if you follow the link it should set it all up for you!

https://earth.nullschool.net/#current/wind/isobaric/10hPa/overlay=temp/orthographic=5.87,90.25,327/loc=109.790,44.598

What I'm seeing here is that the LP Polar Vortex has already been shoved off "Pole Position" by the HP which is warmer than the LP PV.

Then if you look where I've placed the marker, there's an area that's much warmer than the surroundings - OK -29C isn't warm but comparatively it is against -72C.

Is this wave 2 starting already or is a little knowledge a dangerous thing?

 

 

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On 18/12/2018 at 21:55, Bring Back1962-63 said:

1. Before I start, I should say that you have a most unfortunate habit of either misquoting long posts, cherry picking and quoting out of context or missing the main points being delivered in the post. You have actually managed to achieve all of these in only two paragraphs of your "observations"!

....

2. The main paper that we're both referring to is:  Orography and the Boreal Winter Stratosphere: the Importance of the Mongolian mountains  (click on the title for a link to the portal abstract where there's a link to the full paper).........I note that you referenced this paper about 3 months after Malcolm found it and I reviewed it. - so you must have read it but it seems that you are dismissing some of the findings although you do not directly say that - very puzzling.

.........

3.

  • This is NOT the amplitude of the Waves but by the mountains altering the propagation pathways of the waves poleward and by also allowing more waves to propagate vertically into the stratosphere.

.....

4. I feel that this is where several scientists have misunderstood this "new" theory (or in some cases are not prepared to entertain something that rather challenges conventional wisdom).

.......

5. Overall, the point here is that whatever the more significant factor (which might well vary during different episodes) the strongest EAMT spikes appear over the Mongolian Mountains and especially the Altai range.  The vertical propagation on occasions can be so strong that it influences the lower mesosphere and with waves breaking from very high levels. 

....

6. Finally, the part where you misquoted me the most was my reference to the 2009/10 winter. Firstly, as we know, every SSW is different and one should use analogue years with great caution.  The references that I made to that winter was in relation to how well primed the troposphere and surface was to SSW impacts. The difference in the main SSW itself was, as you say, the upcoming event (assuming it does happen which now seems almost certain) will be over 1 month earlier.  I have been referring to the blocking in Russia (right now and expanding HP to come over the next week to days) and another precursor to an SSW is the Asian blocking - probably no coincidence that the powerful jet streak over south and east Asia is propping up that HP.  Then I added in the MJO, AAM, torque factors plus the major "pattern re-set" and a fairly cold and blocked period is expected even without the assistance of an SSW.  To get an early season SSW plus these other teleconnections playing ball more or less simultaneously is particularly encouraging for those looking for cold.  Overall, I am prepared to accept that you may have misunderstood my comments in relation to the 2009/10 winter but most of your "observations" were really pretty wide of the mark.   David ? 

1. There was no misquotation. 'Cherry-picking' is the selection of pertinent points which undermines the main tenet. Anything out of context or misunderstood is because of your inability to post with clarity and accuracy in over 1000 words! Apologies in advance for abbreviating the above quote, but the forum will be thankful.

2. I do not dismiss this paper, though note there are issues with the model used (WACCM) which is investigated in numerous papers. Their own control charts show some differences from reanalysis climatology which may or may not be significant. FWIW I linked to the paper on April 6th on this thread which I believe is prior to it's appearance on the other board - https://www.netweather.tv/forum/topic/88772-stratosphere-temperature-watch-201718/?page=35&tab=comments#comment-3846840

3. Good, this is the jist of the mechanism, yet from the previous two posts this does not appear to be your understanding -

Quote

The lower part of the jet is effectively channelled or funneled northwards and north eastwards and continues until it hits the Mongolian ranges to the north. It is then forced upwards again with some huge uplifts generated - thought to be the strongest anywhere in the world.  This uplift catches up with the upper part of the jet stream and generates powerful vertically propagating rossby (or planetary) waves.

Quote

Note that the previous strong spike was the one that should have created that powerful uplift from the Tibetan Plateau and Mongolian Mountains with those very strong vertical rossby waves which should impact on the stratosphere around Dec 22nd-24th

As explained, this is not how it works. Further, the paper looks at seasonal integrations of zonal EP flux and refractive index and does not describe locations or timing of forcing. For instance the current wave 1 forcing involves a fairly typical north Atlantic/European pattern of blocking episodes.

4. Any evidence of this?

5. Once again, your overall point appears to be at odds with the takeaway from the paper.

6. Lack of clarity necessitated some assumptions to be made, but given the quote -

Quote

Given the vast Russian HP, it seems highly likely that we shall see that push westwards. It may retrogress to Iceland or Greenland for a while too.  According to several specialists, this may well follow the pattern set up during the 2009/10 SSW when we saw many weeks of cold and snow in both Europe, the UK

it was not unreasonable to make a comparison of the pre- and post-SSW periods given the remarkable nature of that winter. Regarding the Russian HP, there was no retrogression of this following the 2010 SSW, Arctic HP developed in situ.

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3 minutes ago, mountain shadow said:

I wouldn't be panicking too much yet as it's only a few members backing off.

hardly encouraging though is it -the venerable Amy Butler has been bullish about upcoming events and this is a real sobering tweet is it not ?

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1 minute ago, Snow Dragon said:

Sorry newbie question.

Please can someone explain why on the one chart it shows a reversal of zonal mean winds and on the other it doesn't? Trying to think of why, but I just can't grasp it and it's been bugging me for a few days.

344254615_zonalwindspeedforecast.thumb.png.4a1b7aa2122a2d14dd9ee77fb1723744.png

Nobody knows lol

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