Stratosphere and Polar Vortex Watch 2020

[Garthvader]

2 hours ago, Vikos said:

/off-topic

I appriciate efforts in posting much info in one post, but could it be possible not to post "hundreds" of charts in one post? It firstly slows down the thread and second kills users on smartphones (useablilty/scrolling and data-traffic).

So to put things into perspective for us normaltons the weather in Europe is gonna take a turn for the worst like extreme cold and tons of snow?

[Bricriu]

5 hours ago, mb018538 said:

Bit misleading from the BBC. It’ll strengthen no doubt, but if it only strengthens to say 10-15m/s as forecast then it’s still a long way below normal and nothing like a usual winter season.

Yes, but  that could still be enough for the Atlantic to exert an influence and bring an end to a cold spell. The Atlantic is in a fairly weakened state now, yet we will have a couple of milders days this week.

Edited January 9, 2021 by Bricriu

[Dorsetbred]

4 hours ago, Vikos said:

/off-topic

I appriciate efforts in posting much info in one post, but could it be possible not to post "hundreds" of charts in one post? It firstly slows down the thread and second kills users on smartphones (useablilty/scrolling and data-traffic).

Given the current movements within the atmosphere I'm sure the poster was only trying to help. The comparative data charts are useful to view what is suggested, and I'm sure the poster was purely trying to substantiate his posting...

Edited January 9, 2021 by Dorsetbred

[Paul_1978]

5 hours ago, Vikos said:

/off-topic

I appriciate efforts in posting much info in one post, but could it be possible not to post "hundreds" of charts in one post? It firstly slows down the thread and second kills users on smartphones (useablilty/scrolling and data-traffic).

Yes I agree with this! Someone else mentioned it too a few days ago.

[Blessed Weather]

As always, a great animation of the SPV from Andrej.

 

[Mike Poole]

1 hour ago, Blessed Weather said:

As always, a great animation of the SPV from Andrej.

 

That is just brilliant, it makes the static charts we see come alive.

[sebastiaan1973]

Wow, what an incredible beautiful animation.

[sebastiaan1973]

At the end of the periode we see a halt to the downwelling till around 100 hPa. Temporarily? I suppose so, 50 hPa, you can argue we see a split; area of higher pressure in between. On the right spot?

[northwestsnow]

1 hour ago, sebastiaan1973 said:

At the end of the periode we see a halt to the downwelling till around 100 hPa. Temporarily? I suppose so, 50 hPa, you can argue we see a split; area of higher pressure in between. On the right spot?

I'm going to assume looking at that chart Central and Eastern Europe in particular are going straight into the freezer.

Could be some truly bitter temps out towards Poland Ukraine Belarus the Baltics..

[Eagle Eye]

7th January

10 January

Expected Stratospheric Movement Due To 7 January starting date. 

Eventual Expected Movement Due To Latest chart updates. 

[Vikos]

According this 150hpa chart, gates for significant artic cold air is given. (outbreak outbreak)

[JeffC]

earth :: a global map of wind, weather, and ocean conditions

EARTH.NULLSCHOOL.NET

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See current wind, weather, ocean, and pollution conditions, as forecast by supercomputers, on an interactive animated map. Updated every three hours.

first showing of the next warming assault on SPV?

 

Edited January 10, 2021 by JeffC
Spelling

[georgiedre]

Quick question to the experts. 

could all these wamings have an impact on the next few winters?  I'm sure each ssw we have there's been a few warmer years afterwards.  Is this true

[bluearmy]

2 hours ago, Vikos said:

According this 150hpa chart, gates for significant artic cold air is given. (outbreak outbreak)

150 hpa will almost always be an imprint of the trop at 500 hpa. 

[Vikos]

2 minutes ago, bluearmy said:

150 hpa will almost always be an imprint of the trop at 500 hpa. 

[Scott Ingham]

5 minutes ago, bluearmy said:

150 hpa will almost always be an imprint of the trop at 500 hpa. 

Just trying to learn more in this area Nick.

If that imprints on the trop what are expected pressure patterns and how did you get to that outcome?

[MATTWOLVES 3]

1 hour ago, georgiedre said:

Quick question to the experts. 

could all these wamings have an impact on the next few winters?  I'm sure each ssw we have there's been a few warmer years afterwards.  Is this true

Every SSW brings around a 66% chance of cold to our latitude...what i will say is SSW events are a big player in many weather events,and can impact the conditions for months.The big SSW that occurred in February 2018 was followed by a record breaking Summer that same year..coincidence! Possibly,but it could have also been a reason for it..There are other factors at play though,especially the going ons of the Pacific ocean.

[Vikos]

1 hour ago, georgiedre said:

Quick question to the experts. 

could all these wamings have an impact on the next few winters?  I'm sure each ssw we have there's been a few warmer years afterwards.  Is this true

Our national Weather Service in Germany (DWD) has it as the "Topic of the day" today, more on this topic to follow this week.

Sudden Stratospheric Warming, Now What?

On 05./06.01.2021 a so called "major sudden stratospheric warming" (SSW) took place. What is behind it and how it came about is to be highlighted in today's topic. The potential effects on the medium and long-term forecast should also be briefly mentioned. Sudden stratospheric warming occurs statistically every two years in the northern hemisphere winter. By definition, one speaks of a "major sudden stratospheric warming" or a marked sudden stratospheric warming if the westerly wind (zonally averaged, i.e. on a degree of latitude, here 60 degrees N circumpolar) in 10 hPa (at a height of around 31 km) turns completely to east wind, i.e. reverses, in addition to a sharp rise in temperature in the upper stratosphere above the North Pole.

A "minor stratospheric warming" (weaker event) is also associated with a marked increase in temperature in the polar upper stratosphere, but not with a complete wind reversal. The background to this definition is a marked weakening of the stratospheric polar vortex, which leads to a large-scale change in tropospheric circulation patterns as well. How did this event come about? Given the starting conditions, the question does not seem out of place. We have had a veritable "La Nina" event (cold phase of the ENSO circulation (see link weather dictionary) in the central and eastern equatorial Pacific) for some time now. In the specialist literature one can read that with "La Nina" events the stratospheric polar vortex is normally not disturbed as much as with "El Nino" events. The background here is the reduced wave flow (heat and momentum flows) into or in the stratosphere at "La Nina". "La Nina" is also related to the Pacific circulation, i.e. roughly speaking high air pressure over the North Pacific, which in turn weakens the more or less persistent Aleutian low. So much for the theory.

What we experienced from the middle / end of December 2020, in addition to sea surface temperatures that were significantly too high in the western and northwestern North Pacific, was an unusually strong high with icy temperatures over eastern Siberia / Mongolia. This explosive mixture of temperature contrasts then led to a significant strengthening of the Aleutian low (see details in the upcoming topic of the day on January 14, 2021 by Helge Tuschy). A similarly strong Aleutian low can usually be found in "El Nino" years. On its front side, strong heat flows are transferred meridionally and especially vertically into the stratosphere. However, this coupling is only possible in the winter half-year, because then westerly winds prevail in the troposphere as well as in the stratosphere of the middle and high latitudes and the wave flows can thus interfere with one another (overlap). In any case, this leads to a weakening of the stratospheric polar vortex (SPV), since wave energy is also converted into thermal energy (i.e. the basically "cold" polar vortex is heated). In our case, stratospheric warming creates an area of high air pressure in the stratosphere (on the Pacific side). Ideally, the SPV is also disturbed from the Atlantic side. Then there is the classic "split" of the SPV.

This year's SSW is more likely to be a hybrid between "displacement" of the SPV from the Pacific and a split, especially since another "warming" with wind reversal (60 degrees N, 10 hPa) is forecast for the middle of the month. All in all, this year's event looks like a lasting disruption or weakening of the SPV, which brings us to the effects that await us. Only briefly will be discussed here, in the TdT of January 14th, 2021 it will be more specific. In any case, the disturbance dynamically spreads over time from the stratosphere to the troposphere (classically characterized by high air pressure over the Arctic). This is accompanied by a clearly negative index of the Arctic and North Atlantic Oscillation (AO and NAO), whereby the reversal of the wind and increasingly meridional flow patterns mean that Arctic air masses penetrate far south. The specialist literature describes Eurasia as a preferred region over North America. In principle, SSW events can now be predicted relatively well using the weather models (even in the medium term, since the models calculate relatively well up to the stratosphere). However, there are still problems with the dynamic coupling of the stratosphere and the troposphere on the one hand and with the assignment to possible tropospheric flow patterns on the other. The latter show quite a variability.

In principle, SSW events can now be predicted relatively well using the weather models (even in the medium term, since the models calculate relatively well up to the stratosphere). However, there are still problems with the dynamic coupling of the stratosphere and the troposphere on the one hand and with the assignment to possible tropospheric flow patterns on the other. The latter show quite a variability. Here, the statistics could help considerably in the future with a better and more systematic recording of events. Another problem is the chronological classification of the effects, as the tropospheric patterns usually only change after about 10 to 15 days after the event. Last but not least, it should be mentioned that the impact of a SSW event on the troposphere can last for two months or more. We almost came to the seasonal weather forecast.

 

Source:

Wetter und Klima - Deutscher Wetterdienst - Thema des Tages - Plötzliche Stratosphärenerwärmung, was nun?

WWW.DWD.DE

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Am 05./06.01.2021 fand ein so genanntes "major sudden stratospheric warming statt"(SSW). Was sich dahinter verbirgt und wie es dazu kam, soll im heutigen Tagesthema beleuchtet werden. Ebenso sollen die...

Translation by google.com

Edited January 10, 2021 by Vikos

[summer blizzard]

58 minutes ago, MATTWOLVES said:

Every SSW brings around a 66% chance of cold to our latitude...what i will say is SSW events are a big player in many weather events,and can impact the conditions for months.The big SSW that occurred in February 2018 was followed by a record breaking Summer that same year..coincidence! Possibly,but it could have also been a reason for it..There are other factors at play though,especially the going ons of the Pacific ocean.

Almost by definition SSW's have no impact on the summer because the final warming (the annual SSW) has long since occured.

Although only a low number of Nino's, most 18C+ summer months do occur in years with ENSO+ conditions.

Edited January 10, 2021 by summer blizzard

[bluearmy]

1 hour ago, Scott Ingham said:

Just trying to learn more in this area Nick.

If that imprints on the trop what are expected pressure patterns and how did you get to that outcome?

that’s the million dollar question Scott ! Regarding the heights, It’s just years of looking at strat charts ...... 150 hpa is generally the same height pattern as the trop - certainly with the major features ........ 

And just looking at the gfs and gfsp .... someone remind me which one is the one we should be taking notice of ........I get confused ....

[Scott Ingham]

1 minute ago, bluearmy said:

that’s the million dollar question Scott ! Regarding the heights, It’s just years of looking at strat charts ...... 150 hpa is generally the same height pattern as the trop - certainly with the major features ........ 

And just looking at the gfs and gfsp .... someone remind me which one is the one we should be taking notice of ........I get confused ....

So what would the major features be on that 150hpa chart

And who knows mate theres far too much volatitlity to call it either way!

[bluearmy]

14 minutes ago, Scott Ingham said:

So what would the major features be on that 150hpa chart

And who knows mate theres far too much volatitlity to call it either way!

Asian vortex , n American trough, Atlantic ridge 

     

[Scott Ingham]

5 minutes ago, bluearmy said:

Asian vortex , n American trough, Atlantic ridge 

     

Brilliant appreciate that thanks it helps a lot to visualise that!

[Vikos]

2 hours ago, bluearmy said:

Asian vortex , n American trough, Atlantic ridge 

     

Thank you BA for pointing out what I was all about

GFS has the same on schedule (still 00z)

The polar vortex has formed a huge main vortex over Eurasia with a center over northern Siberia and a smaller partial vortex over northern Canada (polar vortex split), a strong icy trough lies over Central Europe. Between the high pressure bridge over Greenland and the main vortex over Eurasia, Arctic air masses flow from the Arctic directly to Europe

Edited January 10, 2021 by Vikos

[mb018538]

What goes down, must go up.....like a rocket!