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Stratosphere and Polar Vortex Watch


Paul

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Posted
  • Location: Slovenia (Maribor)
  • Location: Slovenia (Maribor)

New update, for how are the things looking with SSW effect later in the january. Great read.

 

http://www.severe-weather.eu/long-range-2/latest-model-guidance-for-the-mid-late-january-winter-weather-across-europe/?fbclid=IwAR1o3oYT7AQejN6HpRGC2lcdeodlHy074x7GKYM6kP15hI3OXFmWDvzBCBk

Edited by Redbull165
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Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon

As I just posted in the MOD, I'm struck by the similarity of the strat pattern as of about now:

image.thumb.jpg.8e3a1a83c72f9ace3e57fbea35ecea76.jpg

compared to the ECM ensemble mean chart for the trop pattern in 10 days time:

image.thumb.jpg.80feb870769728f17a53c7f557c01c7c.jpg

Edited by Mike Poole
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Posted
  • Location: Stoke Gifford, nr Bristol, SGlos
  • Location: Stoke Gifford, nr Bristol, SGlos
34 minutes ago, Redbull165 said:

Indicates an upgrade compared to their report couple of weeks ago, to my eyes, for UK, esp further East and South.

Earlier report (December) indicated central&East Europe would be main beneficiaries of SSW.

Positive news for UK, if one's preference is cold and snow. Late January it is then.

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Posted
  • Location: st albans
  • Location: st albans
6 minutes ago, Mike Poole said:

As I just posted in the MOD, I'm struck by the similarity of the strat pattern as of about now:

image.thumb.jpg.8e3a1a83c72f9ace3e57fbea35ecea76.jpg

compared to the ECM ensemble mean chart for the trop pattern in 10 days time:

image.thumb.jpg.80feb870769728f17a53c7f557c01c7c.jpg

Pointed this out a few days ago how the upper strat profile imprinted further down some five days later

anyway, I think today sets a date record for min zonal wind at 10 hpa 60N (-9 m/s)

i expect  there will be more to come

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Posted
  • Location: st albans
  • Location: st albans

Updated ec strat from the 00z op is back to lessening the influence of the split as the run gets to the back end ......

the asian vortex begins to pivot sw which I guess reflects the trough backing in that direction and encompassing nw Europe .....what if this pivot sw brings the two vortices together ???

Yesterday’s 30hpa day 10 v today’s day 9.5

A009AF5A-E725-42F6-A33E-DE37E7863929.thumb.jpeg.2b95ab648834a327f60279833fe820b5.jpeg   851F32E3-17E2-4F49-9664-65E9CF311A1D.thumb.jpeg.2556e3e3a6953ae8b979a09e73d864f2.jpeg

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Posted
  • Location: Netherlands close to the coast
  • Location: Netherlands close to the coast
4 minutes ago, bluearmy said:

Updated ec strat from the 00z op is back to lessening the influence of the split as the run gets to the back end ......

the asian vortex begins to pivot sw which I guess reflects the trough backing in that direction and encompassing nw Europe .....what if this pivot sw brings the two vortices together ???

Yesterday’s 30hpa day 10 v today’s day 9.5

A009AF5A-E725-42F6-A33E-DE37E7863929.thumb.jpeg.2b95ab648834a327f60279833fe820b5.jpeg   851F32E3-17E2-4F49-9664-65E9CF311A1D.thumb.jpeg.2556e3e3a6953ae8b979a09e73d864f2.jpeg

Have you looked at https://www.stratobserve.com/misc_vort3d ? Not EC but if you look at it in 3d it seems the 3 daughters are intend in wiping each other out

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Posted
  • Location: Near King's Lynn 13.68m ASL
  • Weather Preferences: Hoar Frost, Snow, Misty Autumn mornings
  • Location: Near King's Lynn 13.68m ASL

Another eye-catching GEFS mean at 10hPa 60N this morning:

 

Edit: Ignore the cached thumbnails. Click the actual images to see the up to date versions. The current 0z mean dips to -16m/s.

Edit2: A little experiment:

epsmean10hPa60N.png?v=1.0

Ok, so you can bypass the thumbnail caching issue by appending a unique query string to the url, e.g. ?v=1.0, as I've done above.

Edited by Yarmy
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Posted
  • Location: The Netherlands
  • Location: The Netherlands

Possibly a DSW.

Hence, the new classification classifies SSWs when the ZMZW reversed at a thickness of at least 80

hPa between 10 and 100 hPa for a band between 60 and 70N for at least two days in a 5-day period.

Since the new classification method aims at classifying SSWs based on their thickness, it is

subsequently referred to as the Deep Stratospheric Warming (DSW) classification.

http://bibliotheek.knmi.nl/knmipubIR/IR2018-05.pdf

With significantly stronger impact on troposphere (picture shows the 300 hPa anomaly) than an ordinary SSW.

Anyway, plenty of downwelling in the long run. 

Knipsel.PNG

Knipsel2.PNG

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Posted
  • Location: Home :Peterborough Work : St Ives
  • Location: Home :Peterborough Work : St Ives
1 hour ago, ArHu3 said:

Have you looked at https://www.stratobserve.com/misc_vort3d ? Not EC but if you look at it in 3d it seems the 3 daughters are intend in wiping each other out

It becomes a very complicated mess after a while and given the lack of resolution (at least compared to EC) I doubt the dynamics are being modelled correctly and probably being reflected in the fluctuating trop forecasts 

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

Sounds like we're finally seeing the models start to show, at the furthest reaches, the lagged downwelling process that involves recovery of zonal winds above the reversal zone. This being more widespread than the (relatively) fast response that focuses on switching the AO negative; a grand slowing of surface zonal flow right around the hemisphere between around 55 and 65 N. Or so I currently understand it to be!

Effects already starting to become apparent right at the end of the GFS 12z, with the tropospheric vortex imprint extremely ragged and the 'wedges' of high pressure able to stick around and force the Atlantic troughs into submission more.

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Posted
  • Location: Methil, Fife
  • Weather Preferences: Baltic
  • Location: Methil, Fife

Wondered if anyone could help with this one. I understand that the PSC clouds are formed under very low temperatures and the graph is showing record low levels of these cloud types for this time of year. I would imagine this is due to the ongoing prolonged warming over the pole currently  and because of this an increase in ozone can take place. During a solar minimum or as now approaching one, ozone can recover year on year and subsequently reduce solar input further meaning colder winters? Wishful thinking maybe or is this a trend to look for in coming winters? 

Screenshot_20190105-201451.thumb.jpg.316f880985f111a579dd686320edb257.jpg  Screenshot_20190105-201619.thumb.jpg.9ea8e00ff34f899b256b79dab3bdf06d.jpg

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Posted
  • Location: Slovenia (Maribor)
  • Location: Slovenia (Maribor)

On ECMWF model we can see the downward propagation is still lagging in the area below the 100 hPa in the troposfere. This SSW event is really slow with its effect. But I hope it will be worth the wait.

ecmwfzm_u_f240.thumb.gif.dd890dc62874b34ebe90318d260ce641.gif

Edited by Redbull165
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

The GFS op is improving every run, very very slowly it is showing the signs of downwelling, It could be one of those times where slow is better, the split is still massive at 10mb at 384 so if the split does hit the bottom of the atmosphere, it could be a long protracted spell of high latitude blocking as any significant uptick in zonal winds seems to want to also be slow to downwell.

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Posted
  • Location: Milltimber, Aberdeen ~ 80m asl
  • Location: Milltimber, Aberdeen ~ 80m asl
1 hour ago, Redbull165 said:

On ECMWF model we can see the downward propagation is still lagging in the area below the 100 hPa in the troposfere. This SSW event is really slow with its effect. But I hope it will be worth the wait.

ecmwfzm_u_f240.thumb.gif.dd890dc62874b34ebe90318d260ce641.gif

I'm curious to see how well that matches with reality in 10 days time. If that forecast is to be believed it explains why there would be nothing of interest being shown in the models until well beyond 17th. Hopefully the models are underplaying the rate of downwelling.

If someone has a link to view these charts as observed on a daily basis since the split that would be most interesting. Also curious to monitor if there will be moderation of the negative values as it propagates down into the troposphere.  

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Posted
  • Location: st albans
  • Location: st albans
38 minutes ago, feb1991blizzard said:

The GFS op is improving every run, very very slowly it is showing the signs of downwelling, It could be one of those times where slow is better, the split is still massive at 10mb at 384 so if the split does hit the bottom of the atmosphere, it could be a long protracted spell of high latitude blocking as any significant uptick in zonal winds seems to want to also be slow to downwell.

Yes feb - the 00z run actually downwelled all the way by day 16 at 60N !

89E841E3-E61C-46E7-AE5A-37123686F003.thumb.jpeg.7c9f363bafa6f81e436ce52922b571ae.jpeg

Edited by bluearmy
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Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

This looks more encouraging from the GFS re: downwelling, although FI still, hopefully this change from the model will continue and will likely be reflected in better troposphere patterns developing for us.

 

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
5 hours ago, bluearmy said:

Yes feb - the 00z run actually downwelled all the way by day 16 at 60N !

89E841E3-E61C-46E7-AE5A-37123686F003.thumb.jpeg.7c9f363bafa6f81e436ce52922b571ae.jpeg

12z none too clever though a residual low heights over Greenland signal.

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