Stratosphere and Polar Vortex Watch 2020

[snow mad]

Also prior to the ssw there was a disconnect between the trop and pv. So any return to normal doesn’t guarantee the return of zonality 

[DEYS(Kent)]

Wrong thread

Edited January 13, 2021 by DEYS(Kent)

[danm]

 

[Dansgaard-Oeschger]

Would I be right in saying what happens to this daughter PV is key to the wobbles in the models at the moment?

[chionomaniac]

3 hours ago, Dansgaard-Oeschger said:

Would I be right in saying what happens to this daughter PV is key to the wobbles in the models at the moment?

It certainly wont help, but would need to see what is happening lower down the strat towards the trop.

LOL whatever happens following a SSW there always seems to be some arm of vorticity or positional daughter in the mix to thwart us.

[sebastiaan1973]

3 hours ago, Dansgaard-Oeschger said:

Would I be right in saying what happens to this daughter PV is key to the wobbles in the models at the moment?

 

That's 10 hPa. These are from yesterday EC12h. I presume they haven't change a lot at 192h.

Overall we see the same pattern with the vortex displaced to Eurasia with a part at eastern Atl. ocean. This makes room for high pressure on the western side.

 

[lorenzo]

Couple of gifs looking through the layers.. vortex vacates one side of the globe on the Berlin view at D10..

Lower down we can see the current chaos playing out around Greenland.

Still of Day 7 looks the most dynamic in the 380K loop... lots of fun still ahead resolving this lot !

[PiscesStar]

Guys what's the latest on things are they still looking rosy in here for the UK??  

[snowblizzard]

1 hour ago, Snowfish2 said:

Guys what's the latest on things are they still looking rosy in here for the UK??  

Feels as if it's all losing momentum and being watered down for UK! 

Not sure about USA , I think forecaster's there are still expecting artic outbreak in NE?

[mushymanrob]

3 hours ago, Snowfish2 said:

Guys what's the latest on things are they still looking rosy in here for the UK??  

Indeed.... whats happening? hows the downwelling from SSW1 going?  hows SSW2 going? what are the long term impacts?  it seems strange that theres been so much information being posted in the run up to the SSW, now its underway everythings gone quiet .

Those of us without the knowledge or understanding of the Strat charts but are keen to find out look to you others who can for help and info so we can learn too...

[lorenzo]

The GIFS I posted above hopefully help a little in terms of what is being modelled currently, I wish I had all the answers !

The Berlin GIF above shows the core of the vortex shifting to the Siberian side at 10hPa and in doing so it becomes coherent again, interesting dynamics as it is almost magnetic in absorbing the Greenland Daughter Vortice, in doing so this whips across the Atlantic. Thereafter, the US side of the hemisphere appears drained of core vorticity. Granted this is higher up in the strat and a longer term direction of travel, also how does this imprint into the troposphere remains a question.

Then the other GIFs further down, see the hPa labels show just how chaotic this process is in terms of that same transition, the energy which has vacated the Greenland locale at 10hPa is still 'active'. Hence, the singular slide for Tuesday where it would appear wave breaking maxes out. 

This makes working out what is next massively difficult and will defer to experts on Twitter for views here in terms of latent impacts.

D10 @ 10hPa

D10 @ 50hPa

D10 @ 100hPa Berlin / d 5/7/10 @ 250hPa NASA

The last series is clearly quite chaotic as energy transfers beneath the block and we can see the alignment somewhat in the NWP model output. 

If the longer direction of travel is for a picture to develop where we see the 10hPa and 50hPa profiles eventually imprint on the troposphere, well - one can imagine. A big avenue for a block and a mass of cold to tap into. The vortex regrouping at 10hPa as per above will also account for the reasonable / strong recovery in u wind which some may look at to say, oh well that's the SSW done with.

Here is the warming profile and zonal wind profile vs deviation from previous 60 day mean, and I think they show the 'slow-motion' transfer down the column of the SSW.

Looking at all things considered, the daughter vortice - it's disruption, how quickly the energy transfers to the larger vortex are a great example of why it's all a good watch as another 'flavour' of SSW unwinds. We know to expect volatility in output and hopefully the above kind of outlines why to some extent. Hopefully some others can join in to add further insights. It is a monster W1 and remain hopeful we will still be seeing impacts lagged for some time. Right now in conclusion it is just too difficult to call with certainty. It's a new SSW and still learning from it.

Edited January 14, 2021 by lorenzo
Deleting additional chart added in error

[Vikos]

After we had the first wind reversal at the beginning of January, the next should take place in the second half of January, which is definitely a striking event for the stratosphere.

The question now arises how this development can affect our weather, including the results of the scientific study by Domeisen et al. is used: This work comes to the conclusion that after a SSW, from a statistical point of view, a clearly negative NAO (see DWD Lexicon) often prevails. It is also stated that, depending on the respective general weather situation at the time of SSW, certain scenarios for the weather events subsequently arise in Northern and Central Europe, among others.

In fact, in the coming weeks the cold air body that has so far prevailed over South and East Asia will increasingly shift to Siberia and also include Scandinavia - see the graphic attached to the topic of the day, where the anomaly values (deviations) of the 2 m temperature from one 20-year model climatology for January 18-25, 2021.

The prediction is made more difficult by the fact that the approach of the Arctic body of cold air increases the temperature contrasts between the land masses and the North Atlantic, including to Canada. This stimulates the formation of strong low pressure areas. Their influence on Europe in the form of very mild air masses and the Arctic cold air expanding into Northern Europe are a breeding ground for events that may potentially deviate from the climate, be it in the form of particularly mild / stormy phases or strong north / east winds with icy cold.

The past has shown that strong cold air ingresses occur more frequently in Northern and Central Europe after an SSW, but there is no guarantee for this. The option for a section with arctic air masses is given solely by the proximity of the body of cold air, as well as the formation of distinctive air mass boundaries with all the harassment that winter weather has to offer.

This is also shown by the wild jumping of the weather models in the extended medium term (end of January) between very warm and icy cold, but very often with increased storm potential for Western and partly also Central Europe. Since the effects of a SSW, should you work your way down, influence the weather in the troposphere with an average of around 10 to 15 days delay, but a technically exciting second half of January and an interesting February can be expected.

How extreme such an event can be became apparent at the turn of the year in the Asia-North Pacific sector. Since the polar vortex weakened early, especially over Asia, there repeatedly icy polar air flowed south and drove the air pressure in Mongolia, among other places, to over 1090 hPa at the end of December, which would represent a new world record after verification.

After the icy air mass reached the north-western North Pacific with maximum temperatures of well below minus 40 degrees Celsius, numerous violent storm lows developed, with a core pressure of estimated 921 hPa and 924.8 hPa (both records) measured on Shemya (Alaska) at the turn of the year has blown the previous air pressure record for extra-tropical low pressure areas in the North Pacific. In addition, massive snow fell over parts of Japan (in the mountainous regions and partly down to the coastal regions) (e.g. Takada with 103 cm in 24 hours and 187 cm in 72 hours, both values an all-time record even for the snow-tested region).

Source:

 

/SiteGlobals/StyleBundles/Bilder/Allgemein/OpenGraphImage-DWD-Logo.jpg;jsessionid=5CDFD43526DF0C94149AE6E94A24DED6.live11042?__blob=normal&v=3

Wetter und Klima - Deutscher Wetterdienst - Neuestes Thema des Tages

WWW.DWD.DE

 

 

[snowblizzard]

According to Met Office 10 day trend (Alex Deacon) the SSW has happened but it didn't result in a reversal, just a weakening of the polar vortex.

They expect the weakening to continue into next week.

So, presumably, that means that cold arctic air is less likely to flood into lower latitudes?

Edited January 14, 2021 by snowblizzard

[ALL ABOARD]

14 minutes ago, snowblizzard said:

According to Met Office 10 day trend (Alex Deacon) the SSW has happened but it didn't result in a reversal, just a weakening of the polar vortex.

They expect the weakening to continue into next week.

So, presumably, that means that cold arctic air is less likely to flood into lower latitudes?

I seen it, but not sure what he meant. 

At 60n the winds have reversed twice, once from the initial warming and the second time from the minor warming. 

Maybe he was referring to the vortex not splitting.. But they did definetly reverse. 

[snowking]

47 minutes ago, snowblizzard said:

According to Met Office 10 day trend (Alex Deacon) the SSW has happened but it didn't result in a reversal, just a weakening of the polar vortex.

They expect the weakening to continue into next week.

So, presumably, that means that cold arctic air is less likely to flood into lower latitudes?

I haven't seen the video so I'm just surmising here, but I wonder if he meant that whilst the polar vortex was significantly weakened, it wasn't taken out altogether.

If he actually said that it didn't result in a reversal then that is factually wrong (and still is even today), but I suspect he was probably referring to the former.

[Bricriu]

38 minutes ago, snowking said:

I haven't seen the video so I'm just surmising here, but I wonder if he meant that whilst the polar vortex was significantly weakened, it wasn't taken out altogether.

If he actually said that it didn't result in a reversal then that is factually wrong (and still is even today), but I suspect he was probably referring to the former.

I  saw the video i think he meant without it being taken out the chances of a severe cold our break are reduced

[Mike Poole]

1 hour ago, ALL ABOARD said:

I seen it, but not sure what he meant. 

At 60n the winds have reversed twice, once from the initial warming and the second time from the minor warming. 

Maybe he was referring to the vortex not splitting.. But they did definetly reverse. 

It does now look as though the vortex is splitting, this from the Berlin site for tomorrow based on yesterdays ECM 12z:

And this remains a reversal (-9.7 m/s).  I think the current model volatility might resolve itself a bit after this.  

[sebastiaan1973]

This is a really good EC46.

[sebastiaan1973]

Latest EC46 10 hPa.

[Nick F]

Definitely split in the SPV at 10 hPa looking at 12z EC in the next 24-48 hrs, before the smaller daughter merges back with the main displaced vortex over N Russia 

Edited January 14, 2021 by Nick F

[Catacol]

Hmmm - best looking strat forcings for a week or so as we experience the trop impact of the current displacement. ECM now spotting renewed wave 2 forcing from as early as day 4, and by 7/8/9/10 it is nearly as substantial as it was when the vortex nearly split last time

Note the strong strat block helping cement the Greenland anomaly and the fresh warming coming from the Euro/Asian side

Vortex splits - and magnitude of the forcing is on the way up to this.

With the vortex stretched and weakened could we be seeing the beginning of a knock out blow? Daughter vortices sent spinning to east Asia and Canada. Greenland heights to find purchase closer to Scandy? Atlantic jet reinforced, but forced southerly?

This would support the seasonal monthly forecasts for February. It is just possible that the cold January - slightly frustrating in its end product so far - leading to a cold February scenario is getting some real traction here now. Most upbeat I've felt in a few days, since output became so confused and cold rain instead of snow so far the result for many. However - I saw flakes today  - and I might well see a good few more on Saturday. Cant complain!!

[bluearmy]

4 hours ago, snowking said:

I haven't seen the video so I'm just surmising here, but I wonder if he meant that whilst the polar vortex was significantly weakened, it wasn't taken out altogether.

If he actually said that it didn't result in a reversal then that is factually wrong (and still is even today), but I suspect he was probably referring to the former.

Not only is it obvs reversed but today is a date record at -6 m/s ! 

[snowblizzard]

1 hour ago, bluearmy said:

Not only is it obvs reversed but today is a date record at -6 m/s ! 

He probably meant to say that it didn't actually split?

Edited January 14, 2021 by snowblizzard

[bluearmy]

Another date record!
 

gfs op doing strange stuff late on sending the core of the spv to Alaska !  Gefs mean obvs not on that page with a more central locale  but there  could be a fairly wide spread on that 

certainly strong evidence that the mid strat is imprinting on the trop  - but there will be differences and those differences from the macro to the micro can have a huge effect on an island at the eastern edge of a huge warm ocean .....

[chris55]

Just here musing how the Atmosphere reacts to a SSW......Ive written an analogy, does it make sense, is it true? Or is it nonsense lol. 

 

Imagine the layers of the atmosphere like a stack of puzzles one on top of each other.

The very first puzzle at 1 hpa has 6 pieces, as you move down through the layers each puzzle has more pieces right down 500 hpa and below, with the lowest puzzle being a 1000 pieces.

Now a SSW disrupts these puzzles, firstly the top one, and that knock on effect moves down through them all. Imagine the lowest most complicated puzzle is eventually messed up, so essentially the atmosphere is in a state of chaos (against the norm) and there is bits of puzzle everywhere! (sometimes the lower puzzles remain solid and uneffected, this means the SSW hasn't propagated the atmosphere)

The simple puzzle at the top, with only a few pieces begins to right itself and that puzzle is remade, relatively easily. This rebuilding  process works its way down the layers....however with such a complex puzzle at the lower levels it can take a long long time for all those pieces to be put back together, even when the SSW event is over. This means the effects of a  SSW can have much longer lasting effect on the lower atmosphere and can go on for a protracted period.

Edited January 15, 2021 by chris55