Stratosphere Temperature Watch 2012/2013

[chionomaniac]

I haven't really had much time to look at the charts earlier but have picked out the best ones tonight.

So we are seeing a wavering wave 2 event that is causing the vortex to split at around day 8-9 right into the middle stratosphere.

http://wekuw.met.fu-...var=ha2&lng=eng

If one follows the charts above, we can see the wave reduce and then increase in intensity. It is the second wave increase that splits the polar vortex - this was suspected all along when the split was first forecast. This split is very much tropospherically induced - mainly as a result of the strong ridging on the Pacific sector. We can see that this has created a situation where a warming is upwelling from the troposphere into the mid levels of the stratosphere by day 10.

very strong at 70 hPa:

and now reaching 30 hPa:

This is the first half of the story and is very much respobsible in the tropospheric northern blocking outputs seen - and we still don't know where or how the vortex will reform. Or do we?

Well, the second half of the story can give us a clue. It very much looks like the Pacific high could get replaced by an Aleution low which is a ripe position for possible wave number 1 feedback into the stratosphere. If this occurs then it will be different to the trop up split through the vortex. This is more likely to come in the form of an over the top through the surf zone type of format. And this is likely to be seen in the form of a displaced vortex from the pole ( towards the Atlantic sector initially then probably to Eurasia - in the strat). As the vortex displaces a warming occurs towards the Pacific sector and will hopefully propagate downwards. GP touched on this last night and the evidence of a top up warming/ displacement scenario is clear to see in the extended outlook at the top of the stratosphere.

Long term, this could be great news. Not only are we seeing the stratospheric vortex being disrupted from below, preventing the cooling vortex from influencing the troposphere, but it looks like that by the time that this wears off the upper vortex has warmed, hitting the upper cold temperatures and vortex strength.

I suspect that if that is the case then any mild winter interlude, following the initial wave 2 split, could be very short indeed.

[chionomaniac]

Just a post to confirm what has been said on the model thread.

Last nights post still stands, regarding any mild interlude.

All signals are pointing to the polar vortex reforming and displacing to the east Atlantic/ Eurasion side of the pole.

Here is the growing wave 1 signal:

http://wekuw.met.fu-...var=ha1&lng=eng

And here is it's (forecast) affect right down at 70hPa

With such a displacement one could see a North Atlantic ridge at the very least with a west based -ve NAO

[bluearmy]

Just a post to confirm what has been said on the model thread.

Last nights post still stands, regarding any mild interlude.

All signals are pointing to the polar vortex reforming and displacing to the east Atlantic/ Eurasion side of the pole.

Here is the growing wave 1 signal:

http://wekuw.met.fu-...var=ha1&lng=eng

And here is it's (forecast) affect right down at 70hPa

With such a displacement one could see a North Atlantic ridge at the very least with a west based -ve NAO

strong indications that strat temps at the pole will be heading above average in a fornight. the ecm zonal wind forecast continues to squeeze the direction of flux towards the lower lattitudes. even with a west based - NAO, we could well have the jet far enough south across the atlantic to stay cold in nw europe.

[Recretos]

First I have to say Hello! New to this forum, and found this topic while I was searching for some stratosphere info on the web. Thank you Google. Quite a debate I must say, on a real high level. I wont interfere with your debates, so I am just going to share my thoughts occasionally. My first post post might be a bit sluggish, but I promise I will try to get in the overall flow of this topic.

Things seem to be on a roll (no pun intended) against the polar vortex, or at least that's how I see it. Better defined easterlies starting to appear.

Not that surprising, given the High building into the polar circle. I find it quite amazing how the ensemble mean is still keeping a 300+ anomaly on a 10-day range. Talk about ensemble consensus.

Looking "cool", temperature wise.

Now as it was already pointed out, it looks like the P.V. will reform after this split-up that is being almost literally thrown in our faces by the models.

I don't want to speculate or anything, especially because its quite far out. But am I the only one glad to see this appearing in the models? And I am sure you have all seen it already.

This is a bit awkward post, but I promise I will improve with time.

Best Regards.

[beng]

With such a displacement one could see a North Atlantic ridge at the very least with a west based -ve NAO

Thanks Ed - that partly answers the question I just asked Stewart on the model thread.

[chionomaniac]

Welcome Recretos.

We look forward to your input.

[AWD]

Appears to me that the warming forecast over the pacific is getting bigger & bigger;

http://cdn.nwstatic.co.uk/gfsimages/gfs.20121122/12/384/npst30.png

[Isolated Frost]

This from La Bise on facebook

Imagine that it's football, one team is called Mild Winter Weather and the other Cold Winter Weather and they've started a game. MWW has one star player, Polar Vortex, when he is on song, CWW can't do much aside from the odd move and a hammering is the outcome. That said, CWW have one big bruiser at the back called Wave Propagation and he has just put a reducer on Polar Vortex who is seen wobbling baddly on the pitch. CWW is going to take advantage of that and it's only a matter of time before Wave Propagation put another reducer on Polar Vortex, the old bruiser is pumped up. The question is how long will he wait for that and will Polar Vortex managed to influence play for more than a few minutes when he recovers from the first tackle.

In the meantime, in CWW, morale player Stratoshperic Warming seems to want a go too and he starts nibbling at Polar Vortex ankles too. Standing aloof, enigmatic, is Sudden Stratoshperic Warming. If he decides to turn on the show, then Polar Vortex is toast, he is simply too good for him to handle and CWW will simply run riot...

Superb!

Edited November 22, 2012 by Isolated Frost

[Bishop Brennan]

Lol that is absolutely fantastic - great find Isolated Frost

Now then, I wonder if we can persuade Chio, GP etc to word all of their future musings in a similar style.......

Bish

[lorenzo]

This is an extract from the conclusion of the Gerber paper. Looking at the CPC charts at the high levels kept seeing random pockets of higher temps and wondered why they appeared almost in isolation and completely randomly? Not sure if this is correct explanation so please correct my thinking if am off on one here.

The theoretical work of Charney and Drazin (1961) suggests that a stronger

vortex will limit Rossby wave propagation into the stratosphere, thus reducing the amplitude of the Brewer–

Dobson circulation.

In the lower stratosphere this provides the correct intuition: the net wave forcing of the stratosphere

is reduced when the vortex is colder, especially when there is no stationary wave forcing in the lower

stratosphere, as explored by Kushner and Polvani (2004).

At upper levels, however, wave breaking increases with a colder vortex, as potential vorticity gradients along the edge of the vortex create a wave guide higher into the stratosphere.

In effect then has this downward trend to a very cold temperature at 30hpa assisted the creation of activity at 1 hpa ?

The strong warming signalled on CPC charts continues

[lorenzo]

Couple of charts from the Berlin site this morning.

Vorticity shows the vortex heading into two distinct vortices

The Wave 2 reinforcement continues

The spilt at 30hpa inside 120 hrs then out to 240 hours where the warming wave can be seen clearly as has been trailed on the GFS charts.

Vortex certainly getting a beating from all angles. The flux graphs also show zonal winds running lighter again and the last 3 days EP Flux are strongly directly North or Poleward.

[chionomaniac]

And Lorenzo that is some split modelled at 10 hPa.

http://wekuw.met.fu-...ast=all&lng=eng

Really high up and lasts until the end of the run.

So significant for achieving cold synoptics.

Edited November 23, 2012 by chionomaniac

[Duane S.]

To add to that Zonal winds, despite increasing raging away at the top, just can't propogate down to the middle of the stratosphere, the 10 day forecast show these backing off even more today

I always wondered if there was a tipping point for all of this and had we managed 30 m/s @ mid strat for a reasonably sustained period things would not be looking as helathy as they do now. We will never know!

[Recretos]

Looks like there will be a decent amount of WAA into the polar circle, on the west side of the Azores High expanding into Greenland. And also from the south flow on the west side of the Aleutian blocking.

Also a positive factor is most defiantly the warm AMO.

As a result of the overall activity, AO and NAO currently forecasted to "plummet", as one would expect from movements and pattern changes of this magnitude.

Things really shaping up.

Best regards.

P.S.: Would someone please be kind enough, to explain the theta levels in mb height? I understand all the charts and graphs on the FU Berlin site, but I just can get the right idea of the height of the theta levels, on which vorticity is presented. I have the idea of Higher theta-lower heights, but cant get the idea of the actual height. Google wasn't of much help either.

[Severe Siberian icy blast]

Looks like there will be a decent amount of WAA into the polar circle, on the west side of the Azores High expanding into Greenland. And also from the south flow on the west side of the Aleutian blocking.

Also a positive factor is most defiantly the warm AMO.

As a result of the overall activity, AO and NAO currently forecasted to "plummet", as one would expect from movements and pattern changes of this magnitude.

Things really shaping up.

Best regards.

P.S.: Would someone please be kind enough, to explain the theta levels in mb height? I understand all the charts and graphs on the FU Berlin site, but I just can get the right idea of the height of the theta levels, on which vorticity is presented. I have the idea of Higher theta-lower heights, but cant get the idea of the actual height. Google wasn't of much help either.

It's great to have someone else with great insight to the stratosphere, you really no your stuff, so between yourself , chio , and gp we really are in a amazing position.

[chionomaniac]

I know roughly where the height levels are for the theta values, Recretos, but couldn't give you am actual value without further research. I think that Brickfielder who posts here may know as he has often referred to the heights in the past.

Edited November 23, 2012 by chionomaniac

[chionomaniac]

If Carlsberg did vortex splits.......

This is from the GFS 00Z and we witness the split with a perfect lobe pointing to Scandi from the Eurasion daughter vortex. That just directs the cold our way.

We have increased warming on the 30 Hpa forecast chart today:

but nothing at 10 hPa yet . We may need the downwelling to achieve warming there.

[sebastiaan1973]

Today there is no Matt Hugo update about EC32?

At the belgium website weerwoord (weather word) http://weerwoord.be/...325&tid=1707325

KMI meteorologist Gert has put a text about EC32.

Ben ik nu de eerste, of is Matt Hugo mij toch voor?

Voor wat het waard is: volgens de jongste uitdraai van EC32 blijft ook de periode 10 tot 16 december duidelijk te koud (1 tot 3 graden ten opzichte van de norm) in zowat heel West-Europa. Het gemiddelde voor de luchtdruk op zeeniveau ligt in Zuid-Europa iets lager dan de norm, ten noorden van ons is er weinig afwijking. Voor de neerslag is er geen signaal voor onze omgeving in deze week.

I suppose nobody reads Dutch, so I translate it in headlines.

The latest EC32 keeps Western Europe cold till 16th of december. 1-3 degrees colder than average. Low pressure in south of Europe lower than average. In the north there is no clear signal. Around normal.

I introduced EC32 at weerwoord, with the tweets of Matt Huto, so he wonders where Matt Hugo is

Very nice to see all the international weather/winter lovers together.

Edited November 23, 2012 by sebastiaan1973

[joggs]

Just a quick question Chio, with the strat been fairly cold to start with and with the synoptics on the mods trending good from a coldie point of view, from your own point of view have you ever felt this optomistic re, the warmings gradually showing,wave breaks,torques etc?. Ive limited knowledge on the strat side of things but learning all the time and must say december looks like catching me out as i thought cold start but quickly turnig milder from the 10th Regards.

[bluearmy]

Today there is no Matt Hugo update about EC32?

At the belgium website weerwoord (weather word) http://weerwoord.be/...325&tid=1707325

KMI meteorologist Gert has put a text about EC32.

Ben ik nu de eerste, of is Matt Hugo mij toch voor?

Voor wat het waard is: volgens de jongste uitdraai van EC32 blijft ook de periode 10 tot 16 december duidelijk te koud (1 tot 3 graden ten opzichte van de norm) in zowat heel West-Europa. Het gemiddelde voor de luchtdruk op zeeniveau ligt in Zuid-Europa iets lager dan de norm, ten noorden van ons is er weinig afwijking. Voor de neerslag is er geen signaal voor onze omgeving in deze week.

I suppose nobody reads Dutch, so I translate it in headlines.

The latest EC32 keeps Western Europe cold till 16th of december. 1-3 degrees colder than average. Low pressure in south of Europe lower than average. In the north there is no clear signal. Around normal.

I introduced EC32 at weerwoord, with the tweets of Matt Huto, so he wonders where Matt Hugo is

Very nice to see all the international weather/winter lovers together.

i think matts on holiday in scotland

[chionomaniac]

Just a quick question Chio, with the strat been fairly cold to start with and with the synoptics on the mods trending good from a coldie point of view, from your own point of view have you ever felt this optomistic re, the warmings gradually showing,wave breaks,torques etc?. Ive limited knowledge on the strat side of things but learning all the time and must say december looks like catching me out as i thought cold start but quickly turnig milder from the 10th Regards.

I don't know about optimistic, but I certainly felt confident how last year would pan out.

[cooling climate]

Hi Recretos this should answer your question.

Isentropic Surfaces and the Motion of Stratospheric Air -- If we choose a particular potential temperature, all of the air with this particular potential temperature will form a surface called an isentropic surface. In fact, potential temperature divided by 25 is about equal to the altitude in kilometers (i.e., 400 K = 400/25 = ~16 km and 500 K =500/25= 20 km). Because potential temperature becomes so large at higher altitudes in the stratosphere, it is difficult to move air upward or downward. Stratospheric air tends to remain on an isentropic surface for many days. Vertical motions are consequently very small.

[chionomaniac]

Quite a significant (FI) warming up at the top at 1hPa tonight

[kold weather]

Think that might be the knockout blow if it came to it C?

There have certainly been hints at a warming episode for early-mid December, probably would suggest a fair chance of decent northern blocking towards the end of December and early January...just when most real cold winter tend to get going...hmmm!

[chionomaniac]

One can never be how sure an upper based warming will propagate down.

The knockout blow for me will be when the 10 hPa gets blown away by a warming.

However, in the last few years we have seen that a tropospheric based blow through the base of the strat vortex can have a far greater effect than an over the top warming.