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Stratosphere and Polar Vortex Watch


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5 hours ago, Interitus said:

 

1010817313_Geopotential_anomaly_isobaricinjan20anom.thumb.png.e892ed05550370ec09d139a719c22489.png

And to further elaborate, below is my own version of this graphic from @Interitus , after I apply my "Recretos' 30-second full-HD optimisation procedure". :D  It really is that quick once you know what to do. :)  Colour is of course just a matter of taste. 

geopotentia1lanom1alyiso.jpg             geopotentialanom1alyiso2.jpg

 

Edited by Recretos
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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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Thank you for your work Lorenzo. I am tho a bit confused with the first plot. The enso regime from 1990 to 2001 seems quite off, being all in negative? 

I did one a while ago, I guess I should update it and add SSW dates. Black line is ENSO.

DKRbz-Xk-Xk-AAuxfn.jpg

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11 hours ago, Recretos said:

Thank you for your work Lorenzo. I am tho a bit confused with the first plot. The enso regime from 1990 to 2001 seems quite off, being all in negative

I did one a while ago, I guess I should update it and add SSW dates. Black line is ENSO.

DKRbz-Xk-Xk-AAuxfn.jpg

I think Tony's graph is only referring to the ENSO state at the time of the SSW's, so therefore when there's a big gap in SSW dates, it looks like it has remained in a nina state. Look at the QBO state, they are also only referred to at the time of the SSW's.

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@feb1991blizzard I think that's spot on will re check it only pertains to actual ERA40 SSW dates.

@Recretos knew you would have something cooler ! Look forward to the updated one.

And, @Interitus, thank you for the nudge around Panoply and help with getting it up and running , really cool resource. Lost myself for about an hour with just map parameters and colour scales. Would encourage others with a bit of time to give it a blast :)

 

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The Downward Influence of Sudden Stratospheric Warmings: Association with Tropospheric Precursors

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Abstract

Tropospheric features preceding Sudden Stratospheric Warming events (SSWs) are identified using a large compendium of events obtained from a chemistry-climate model. In agreement with recent observational studies, it is found that approximately one third of SSWs are preceded by extreme episodes of wave activity in the lower troposphere. The relationship becomes stronger in the lower stratosphere, where ∼60% of SSWs are preceded by extreme wave activity at 100 hPa. Additional analysis characterises events that do or do not appear to subsequently impact the troposphere, referred to as downward and non-downward propagating SSWs, respectively. On average, tropospheric wave activity is larger preceding downward-propagating SSWs compared to non-downward propagating events, and associated in particular with a doubly-strengthened Siberian High. Of the SSWs that were preceded by extreme lower-tropospheric wave activity, ∼2/3 propagated down to the troposphere, and hence the presence of extreme lower-tropospheric wave activity can only be used probablistically to predict a slight increase or decrease at the onset, of the likelihood of tropospheric impacts to follow. However, a large number of downward and non-downward propagating SSWs must be considered (> 35), before the difference becomes statistically significant. The precursors are also robust upon comparison with composites consisting of randomly-selected tropospheric NAM events. The downward influence and precursors to split and displacement events are also examined. It is found that anomalous upward wave-1 fluxes precede both cases. Splits exhibit a near instantaneous, barotropic response in the stratosphere and troposphere, while displacements have a stronger long-term influence.

https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0053.1#.W80VfDo8l44.twitter

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3 hours ago, Steve Murr said:

Zonal wind reduction forecast gathering pace !!!

9634E1BF-2C86-4A57-BD0D-27697209CE5D.thumb.png.7ee3135e2d709677cc3afafd73429974.png

Makes sense.GFS fairly consistent with upwelling forecast from the Trop into the Strat to stretch the PV. Looks likely to only be a minor event but every little helps

288532157_Screenshot2018-10-23at15_33_26.thumb.png.5c75820a608ad26ceb869fcd56bf22b4.png573180969_Screenshot2018-10-23at15_33_34.thumb.png.93672eb21449cf1bf490c022d7664862.png

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12 minutes ago, BLAST FROM THE PAST said:

Like it a lot.  This would usher in a cold December particularly say from 6-12 Dec.  Note this

 

BFTP  

It's only 38% though. Let's see if it continues in the coming runs.

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Not to be a party breaker, but 5K is like a normal core oscillation. Can hardly call it a warming event really, let alone count on it to bring colder trop weather. :) And this is a 50mb level, so its even less significant. 

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2 minutes ago, Recretos said:

Not to be a party breaker, but 5K is like a normal core oscillation. Can hardly call it a warming event really, let alone count on it to bring colder trop weather. And this is a 50mb level, so its even less significant. 

Lol, I thought this Ventrice guy knew his stuff? 

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2 minutes ago, Recretos said:

Not to be a party breaker, but 5K is like a normal core oscillation. Can hardly call it a warming event really, let alone count on it to bring colder trop weather. And this is a 50mb level, so its even less significant. 

Yes however for the first time in the last 2 weeks a CF2 perturbed run has forecast a true warming & subsequent reversal @10mb to about -10M/S

The GFS ens suite does seem to allign but as we know there is a bit of a negative bias in there

F0399492-E695-4384-98E3-32BF8DF65B43.thumb.jpeg.4fc2559bb3c01f258008d2bb53c0e395.jpeg

You will note they have updated from earlier...

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14 hours ago, lorenzo said:

Another resource arriving online soon for the winter ahead..

 

 

Interesting that she's actually creating a web page for this, but this chart and others were running last winter, I linked them earlier in this thread.

Here is the one in the tweet (a bit glitchy for some reason)

waveU.thumb.gif.aca96d35880bc58d9f774c8e6dc75752.gif

The updated one is here - http://www.atmos.albany.edu/facstaff/andrea/webmaps/waveUT.gif

Temperature wave (anomaly) - http://www.atmos.albany.edu/facstaff/andrea/webmaps/TwaveAmp.gif - there is also a geopotential version but not working at the moment

GEFS timeseries - http://www.atmos.albany.edu/facstaff/andrea/webmaps/test_GEFSellipse_timeseries.html

 

lliptical diagnostics of the GFS/GEFS -

http://www.atmos.albany.edu/facstaff/andrea/webmaps/GEFSellipseFcast_update.html

http://www.atmos.albany.edu/facstaff/andrea/webmaps/realtimeVortex/GFSellipseFcast.html

http://www.atmos.albany.edu/facstaff/andrea/webmaps/GEFSellipseFcast.html

found from noseying around her Uni of Albany directory - http://www.atmos.albany.edu/facstaff/andrea/webmaps/?C=M;O=D

The GEFS ellipse charts show that some members appear to predict a split in the lower strat.

 

 

Edited by Interitus
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the 06z gfs op had an interesting zonal wind anomoly profile at 10mb end week 2 (indeed weaker than normal throughout the strat)……….

of course gfs ops at day 14/15 are not to be taken too seriously but the strat vortex looks quite displaced on the Siberian side for the time being and the wave 1 forecast from the 06z op was indeed indicative of displacement

Edited by bluearmy
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