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Stratosphere and Polar Vortex Watch 2020


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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
3 hours ago, snowking said:

Lots going both from the bottom up and the top down.

I would usually caveat this by saying single operational run at long lead time, etc. but checking back through recent runs this really is pretty consistent

image.thumb.png.acaf757f0a127751774df9c47919100f.png

Absolutely enormous warming up at 1mb, that's +35c you can see in there (remember, this not an anomaly chart, that is actual temperature) from about day 11 onwards. Warming is still ongoing by the end of the run:

image.thumb.png.eef893ec486237359dce781f5ef7606a.png

Seeping down into the levels below too:

image.thumb.png.b161f3ed7466f63939d45b242a027927.png

Back at the very top, this leads to what looks to be a Wave 2 attack by the end of the run, but I could be seeing things there and it may instead be an all-encompassing Wave 1 - difficult to tell whether that is two distinct waves:

image.thumb.png.334ad21f3a1071dc52c9551101e70be3.png

We then seem to have the more widely advertised bottom-up pressure which leads to at least a partial split from 100mb:

image.thumb.png.21465d5173ba12292f113ed3d7dddd85.png

All the way up to 20mb by the end of the run:

image.thumb.png.e194cd11911f907aa5b45e7ed36e68e6.png

The Wave 1 pressure pretty apparent there too at 20mb.

So we have a situation where we have top-down warming absolutely battering the vortex from the top, and tropospheric forcing causing some fairly significant bruising to the vortex from the bottom. Assuming that current forecasts are correct, the question really must become when, not if, the vortex falls entirely to its knees. I'll leave that to someone far braver than me.

 

 

 

lol -55C I think that could be a reord were it to verify (without checking and just off the top of my head)

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Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
4 minutes ago, bluearmy said:

gfs 12z not far off a tech ssw by day 16. 

i would say reversed down to about 8 hpa

and split too !!

Out of interest how reliable is it at time frame??

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Posted
  • Location: @scotlandwx
  • Weather Preferences: Crystal Clear High Pressure & Blue Skies
  • Location: @scotlandwx
7 minutes ago, The PIT said:

Out of interest how reliable is it at time frame??

SSWs predictability is longer than one may expect... am thinking it's more about when in January vs not if in January... especially if we get anything like the amplification programmed on today's NWP output in terms of that Atlantic Ridging. Beyond that we can call in the Asian cavalry too...

image.thumb.png.7b23b53424110c37255a3eb532b4e458.png

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Posted
  • Location: St Albans, 95m asl
  • Location: St Albans, 95m asl
10 minutes ago, bluearmy said:

gfs 12z not far off a tech ssw by day 16. 

i would say reversed down to about 8 hpa

and split too !!

I'm like a kid at christmas watching this unfold 

Split at every level of the stratosphere apart from 1mb - and  the only reason there's no evident split at 1mb is because there really isn't any evident vortex left to split at this level by this time:

image.thumb.png.94980900a6d99f3f7fdb4e73d4856127.png

Definite Wave 2 action there right at the top, and what's left of the sorry remains of the vortex displaced right off of it's usual happy-place axis and off to the US.

It will hopefully be a really fascinating watch with some really complex interactions as the top down action meets the bottom up action, presumably somewhere between 10-30mb. What happens from there is anyones guess, but with the GEFS and GEM ENS continuing to suggest that monster HP over Asia will keep on breaking travel restrictions and head down to China, I can't imagine +EAMT letting up for particularly long any time soon, so one would suspect that once this longwave pattern sets itself up, it's not going to become particularly fast moving or deamplified any time soon, so continued pressure from the bottom up looks likely.

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Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
3 minutes ago, lorenzo said:

SSWs predictability is longer than one may expect... am thinking it's more about when in January vs not if in January... especially if we get anything like the amplification programmed on today's NWP output in terms of that Atlantic Ridging. Beyond that we can call in the Asian cavalry too...

image.thumb.png.7b23b53424110c37255a3eb532b4e458.png

Got to agree. Been unpacking boxes all day following moving..,and just had time to scan the data again and to my eye things are firming up. I see a 2018 wildcard in play once again, this time 6 weeks earlier than 2018, and a potential seasonal forecast wrecker. As Spock would say.......Fascinating.

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Posted
  • Location: @scotlandwx
  • Weather Preferences: Crystal Clear High Pressure & Blue Skies
  • Location: @scotlandwx

The dynamic tropopause breaks on the EC 12z tonight are things of beauty, especially across the Greenland plateau.

Appreciate this evolution is 10 days out and it's never a given with the nuances of these breaks. However that being said it is great to see this dream wave break uppercut evolution and cross model support to varying degrees dependent on how the residual energy in the vortex seeps into the CWB elements.

The Greenland 'nudge' or 'uppercut' is something that over the years we have seen the PV really responsive too, and following on from the EP assault it is positive to see again. It's probably the one most of us want to see live again. 

Fingers crossed we get that to verification, to witness the aftermath in what will be HD or UHD /4K vs 2009 Cathode Ray Tube view !

 

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

So, last one from me, the 18z backs up the 12z with a split SSW on the way:

0AC61B1B-4396-492B-9070-0CBD0437E22B.thumb.png.2f097f11ace25a4ada796109e81fc19b.png

Just another factor in trying to predict where the winter will go.  But here’s the conundrum:

Are the events that cause a SSW responsible for a cold blocked spell for the UK before the event, or are they responsible for a cold blocked spell for the UK after the event?  

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Posted
  • Location: St Albans, 95m asl
  • Location: St Albans, 95m asl

Slight nuances to the story today but still largely the same. The monster warming at the top of the stratosphere continues and if anything we see even more evidence of Wave 2 attack by the end of the 0z GFS forcing a split between 10-5mb and a complete removal of the vortex from over the pole above.

Less of a split noticeable below this (the bottom up action we spoke about yesterday will always be more prone to swings as this is troposphere dependent) however the core of the vortex in the lower stratosphere looks likely to shift to somewhere east of Greenland.

Two things to note from this. Firstly in the shorter term such a lower stratospheric pattern would suggest that a broad NW European trough is the most likely way forward in terms of long wave features - that isn’t to say there won’t be some of those pesky shortwave lows that spring up and scupper cold chances, but in general we would expect to see higher than normal heights around the mid Atlantic and any such areas of equal longitude.

Secondly, if you can remember back to some of the awesome 3D animations @Recretos has produced of the vortex in the past, you’ll hopefully be able to remember that a happy vortex = a vortex that is spinning away on a consistent axis right through the atmosphere, ideally somewhere close to the pole. Where as what we are likely to end up with over the next few weeks is a vortex whose top at 1mb is located somewhere over towards the US, whilst the bottom down towards the tropopause sits somewhere closer to Svalbard. This leaves us with a very unbalanced and drunk looking vortex (well, it is nearly Christmas I suppose) and means that we should expect less and less influence of a strong westerly vortex around the pole for the foreseeable future - in other words, we should expect extended spells of AO at least at neutral levels, if not negative. 

That’s the minimum. What comes after that if the wave action at the top sinks down lower into the heart of the stratosphere in the first 3rd of Jan could pique the interest of those of a cold persuasion even further 

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)
10 hours ago, Mike Poole said:

So, last one from me, the 18z backs up the 12z with a split SSW on the way:

Just another factor in trying to predict where the winter will go.  But here’s the conundrum:

Are the events that cause a SSW responsible for a cold blocked spell for the UK before the event, or are they responsible for a cold blocked spell for the UK after the event?  

Well there’s the funny thing - SSWs tend to follow highly meridional weather patterns as that’s how the powerful vertical wave activity comes about.

So, one can expect that there will be plenty anomalous weather one way or another beforehand. Sometimes that’s cold for the UK. Other times, persistently mild and/or wet (think Nov 2009).

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Posted
  • Location: Tullynessle/Westhill
  • Weather Preferences: Cold and snowy or warm and dry
  • Location: Tullynessle/Westhill

A probably amateur question, but if the strat vortex is currently de-coupled from the trop vortex, will a strat SSW actually have any affect on the trop? Obviously its better than having a raging vortex up high, but that is what we have currently and the trop is very different. 

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Posted
  • Location: st albans
  • Location: st albans
26 minutes ago, Ravelin said:

A probably amateur question, but if the strat vortex is currently de-coupled from the trop vortex, will a strat SSW actually have any affect on the trop? Obviously its better than having a raging vortex up high, but that is what we have currently and the trop is very different. 

If the upper strat goes into reverse that drives a wave which may downwell into the trop (driving a strong neg AO response). Sometimes that is quick and then followed by several more waves a few weeks apart .......but there is no guarantee that these will downwell. With the upper strat not currently showing a strong vortex (we’re about to show a small increase just above average for a couple days before the drop begins) , an SSW may not look so dramatic - others will advise if downwelling looks more/less likely given other current variables.  I suspect any reversal will indeed head down but with current trop patterns not showing a significantly  pos AO, it may not be particularly notable other than to re enforce the amplified patterns currently predicted across the NH and to drop the AO back neg as it has been courtesy of the arctic high for a while now 

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Posted
  • Location: Tullynessle/Westhill
  • Weather Preferences: Cold and snowy or warm and dry
  • Location: Tullynessle/Westhill

Thanks @bluearmy, that's sort of what I was thinking. Normally we'd be desperate for a SSW to potentially 'upset' a raging trop PV, but with a very disturbed trop PV the most we can hope for is that a  SSW reinforces what we're already seeing.

The 'fear' if there is no SSW would be a reconnection of the trop and the strat to leave the second half of winter zonal. 

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Posted
  • Location: Rotherham, East Dene
  • Location: Rotherham, East Dene
1 hour ago, Mike Poole said:

Strat vortex is toast!

37013F52-079C-4E14-BCCF-79838474E43E.thumb.png.7430b67bd80d93389057b77c7990d5fa.png

That’s the 6z take, good split.

This is a better split than shown two days ago with a slightly larger chunk on the Scandi side and just enough to stop a west based -Nao. That said still wayyyy too early to put the pieces together. Plenty with far more knowledge than me on this subject.

Whats your early views on the tropospheric impact as it stands @chionomaniac

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Posted
  • Location: st albans
  • Location: st albans
10 minutes ago, Ravelin said:

Thanks @bluearmy, that's sort of what I was thinking. Normally we'd be desperate for a SSW to potentially 'upset' a raging trop PV, but with a very disturbed trop PV the most we can hope for is that a  SSW reinforces what we're already seeing.

The 'fear' if there is no SSW would be a reconnection of the trop and the strat to leave the second half of winter zonal. 

Even without an SSW the strat vortex doesn’t look to become v strong over January - hence the trop should continue to lead the dance with some help from the tropics etc re amplification 

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Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
On 15/12/2020 at 11:49, Kirkcaldy Weather said:

Im pretty sure that I posted the links to the papers a few winters ago but just posting this as a kind of experiment 54520137-DC34-4940-A2FC-DD669BC81203.thumb.jpeg.60fe11b5966f0aae2127f4e7ab53720b.jpeg4BD3A2B0-8032-45CA-BDDE-4662B5D91C9B.thumb.jpeg.42267ba42a7c0739b306a0e92897068a.jpegusing the data from the bom site the MJO phases were

phase 2 15th - 20th November 

phase 3 21st - 23rd November 

phase 4 24th November- 7th December 

using the amount of days those papers mention gets a bit complicated in the figuring out but something along the lines of 10th/16th December - 26th / 29th December and 7th / 18th December - 20th / 31st December for possible stratospheric warming which doesn’t look too far off in the current modelling. *not sure if the amplitude of MJO is a factor as the recent phases have mostly been low amplitude/ COD but were still associated with those phases mentioned in those papers*

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2012GL053144

https://journals.ametsoc.org/view/journals/clim/30/21/jcli-d-17-0044.1.xml

http://www.bom.gov.au/climate/mjo/graphics/rmm.74toRealtime.txt

 

 

 

That looks like a pretty decent way of trying to predict strat warming with those end of the month dates looking like it will be getting in the stratosphere, I’ve been keeping an eye for splits D6DFC359-63A8-4E4B-A775-5D88FA3EC90F.thumb.png.06e5760b1470f383393722ab63f90f84.png89D96255-AB70-468E-B253-91D494490D85.thumb.png.54fbf7ade71b6b3ad9afc0477a1902af.png3BC83D0A-D0F8-4B6C-BE47-A01E9A424697.thumb.png.5a9e9593277560a1509033f7a952adec.png7CC4CC0E-8874-4D24-9FB2-DA9A97A10E8F.thumb.png.e6675a6066ead32dc743435eef0cd52f.png41A51E9B-E53B-4993-9444-813A267A06C7.thumb.png.99f558611cab037f2eee2917c73b5892.png93DE0634-1953-4845-A96A-44EB2860A9C6.thumb.png.b3dad20d7fd8357619972fa7f6eaf4f2.pngC1E76658-2D5A-4157-B49F-B995E7E3F19C.thumb.png.0d0015146f9fdf2b430ffffad77246e2.png0FA02E05-1DD9-4FF8-8E3D-C3E1EFE56C5D.thumb.png.7263c96e5b484014c4b6047d7237ada8.png5CB06841-88A7-4E1C-8A4A-53DE7A40668D.thumb.png.8aa7693cb79a2e68fc05e2c110e58fda.pngBF563FD7-ED76-48E9-A1C1-2C0BBFB026C5.thumb.png.32337161055dc2ada7e2cf835cee32ee.png

looks like a quite solid option on the table though there are others that go for a big warmup again without an initial split (possibly getting to one eventually) similar to these 0BD5FCFF-F29C-42F1-84FC-22290A9E6F67.thumb.png.ac25623998e801f17765517a2d90738a.pngFCE79213-1FCD-427A-853E-6EF9869181DB.thumb.png.65372db27e610e2253613267dc7dd86b.png all getting very interesting and I think it’s brilliant seeing all you strat guys with the in depth posts a question which hopefully doesn’t sound too daft - should we get the split is there importance for where the sections of the vortex end up to have the best chance of colder conditions for UK if I remember I think when the vortex finally did split with the Christmas warming of a few winters ago both sections (I think there were maybe even 3) ended up across North America and near Greenland and that paired with the easterlies not behaving normally was maybe why we didn’t benefit from any colder weather

Edited by Kirkcaldy Weather
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Posted
  • Location: st albans
  • Location: st albans

The 06z op looks like it reverses around 65N

the zonal flow at 60hpa by the end is 4 m/s

the zonal flow below isn’t much stronger than that 

If a cold trop pattern establishes within the next two weeks there may not be much going on to move it along

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

Yes plenty of signs now of a weakened vortex.

The warming at the top just starting to show on the Japanese graph

pole30_nh.thumb.gif.6af10736a3a229c0008e49ad50dbd9a5.gif

although it has a way to go from a very cold base but it's a start.

More importantly the lower levels already weakened by continual wave attacks since November show mean zonal winds well below the normal speeds.

1685988018_umedel60(2).thumb.png.8231ff6693738b564b183aeb9201f3a4.png

The blue anomalies show how under par the vortex is.A very distressed beast and looking at the current forecast is not going to recover anytime soon.

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Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

Quite a few splits in that GEFS set probably the most I’ve seen so far and a good few of the rest again have that big increase in warming toward the end 717A479F-71AD-4E4F-88D3-221410EF2EBC.thumb.png.f31a97eebbcb6e0bb2777658378d104d.png185619A6-1E19-4F0C-83CC-D826CE2FCBDA.thumb.png.91ee5800bd82c6d822a7e816ab94de29.png2E6C4819-C150-4858-998B-8E3114B87B67.thumb.png.66ff14a6c6885e7515ce6f545489ab6b.png680C2710-EBA9-45DB-AF6E-150FECAB94BF.thumb.png.9a4530797d0612ec38c2e4840b3e2107.pngD550D224-00D8-4623-8BEB-B5391A2F137D.thumb.png.285c8f95af8c5e20d44f1bd295458a76.png

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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
6 hours ago, Scott Ingham said:

This is a better split than shown two days ago with a slightly larger chunk on the Scandi side and just enough to stop a west based -Nao. That said still wayyyy too early to put the pieces together. Plenty with far more knowledge than me on this subject.

Whats your early views on the tropospheric impact as it stands @chionomaniac

It’s far too early to consider yet. After all any SSW is not forecast in the reliable yet.

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Posted
  • Location: Rotherham, East Dene
  • Location: Rotherham, East Dene
2 minutes ago, chionomaniac said:

It’s far too early to consider yet. After all any SSW is not forecast in the reliable yet.

I did think as much but from a learning stand point i wondered if there wad anything i should look out for. An early indicator of where all the pieces may fall.

Thanks Ed

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