Stratosphere Temperature Watch 2015/2016

[joggs]

He always seems to be moving the goalposts to me. Lol

[Nouska]

37 minutes ago, ukpaul said:

As far as i'm aware I don't think there is one universally accepted definition.

That seems to be an ongoing problem in discussions and tweets but I'm more surprised by his assertion that he cannot recall a stronger warming being shown on previous output - I can think of many!

Also to retweet ECM ensemble means that were generated ten days ago and show as validation is a bit odd.

 

[Yarmy]

4 minutes ago, Nouska said:

That seems to be an ongoing problem in discussions and tweets but I'm more surprised by his assertion that he cannot recall a stronger warming being shown on previous output - I can think of many!

Also to retweet ECM ensemble means that were generated ten days ago and show as validation is a bit odd.

 

I think he just didn't notice the date on the chart. You would have thought that AER would have access to the ECM ensembles, but perhaps they don't. 

[Nouska]

5 minutes ago, Yarmy said:

I think he just didn't notice the date on the chart. You would have thought that AER would have access to the ECM ensembles, but perhaps they don't. 

They might have access but the ECM strict copyright restrictions prevent them from showing directly. They have their own model for the stratosphere but I've no idea whether they use a blend of available data or just one source.

I didn't get the impression from Mr F that the ECM or GloSea5 were showing much of interest in the next two week period.

[chionomaniac]

Judah doesn't have access to Eps strat data

[bluearmy]

1 hour ago, chionomaniac said:

Judah doesn't have access to Eps strat data

This is the first test of the upgraded gefs and gfs op in respect of a potential MMW.

ecm should really wipe the floor in the upper strat re its horizontal resolution layering. However, it got it badly wrong last jan with a couple of day 10 outputs at 10hpa.

the trop gfs 06z towards the end of week 2 looks a bit quick trop response over the Arctic but I don't think it is a response to strat forcing.

[Singularity]

Interesting to consider a very extensive warming but not technically a SSW. A 'BAW' (Big-Ass Warming) perhaps 

I have been warming to the idea of tropical forcing setting up the neg NAO pattern early in Feb and then the big vortex displacement and weakening helping to sustain that setup. Basically along the lines of what GP has been saying for some time now!

 

I noticed yesterday that the positive AO is looking to be a briefer affair than was the case a few days ago, but still a decent enough spike upward. Is that still sufficient to set the stage for any SSW  that does occur to propagate down past the tropopause? 

It's funny really - if the tropical forcing does what GP etc. anticipate, then a SSW will represent gambling while we're ahead, albeit with the odds more in our favour than usual based on the research regarding the role of the Kara high that Chiono and Nouska have discussed.

[Trom]

2 hours ago, Nouska said:

That seems to be an ongoing problem in discussions and tweets but I'm more surprised by his assertion that he cannot recall a stronger warming being shown on previous output - I can think of many!

Also to retweet ECM ensemble means that were generated ten days ago and show as validation is a bit odd.

 

He mentions "extensive" rather than "stronger" does this mean he's talking about area rather than extremes of temp?

[Abyss]

3 hours ago, Nouska said:

but I'm more surprised by his assertion that he cannot recall a stronger warming being shown on previous output - I can think of many!

 

 

He said extensive not stronger. Big difference

[nick sussex]

Theres no vagueness when it comes to an SSW, its either major or minor.

If you don't get the reversal of zonal winds at 60N 10 Hpa then its a minor , if you do its a major. You can't have a sort of major SSW, it either is or isn't.

Putting aside all the complexities in terms of trop response, PV displacement or split you have to have criteria which can differentiate between those major/minor warmings. Otherwise goal posts get moved blurring this.

Edited January 21, 2016 by nick sussex

[wishingforsnow]

I don't know how long it will take high res models to pick up a SSW signal however, Ian F also doesn't discount it completely which is also a good sign.

Not posting on the model thread for now because of knee jerk drama to one set of runs. Meanwhile I have a hunch, as I suppose you guys do too that this period of +AO and milder weather for the next 10 days/2 weeks or so is only temporary towards month's end when it seems a SSW or vortex displacement event may be in our midst quicker than we think to provide colder weather (should it happen during this milder period as some experts are hinting at then it should make the pattern flip to cold right?). 

[Nouska]

27 minutes ago, Trom said:

He mentions "extensive" rather than "stronger" does this mean he's talking about area rather than extremes of temp?

 

12 minutes ago, -Bomber- said:

He said extensive not stronger. Big difference

Accepted but I was considering both aspects.

From 2013 for example    .... 

Just as extensive and stronger in the forecast.

[wishingforsnow]

1 minute ago, Nouska said:

 

Accepted but I was considering both aspects.

From 2013 for example    .... 

Just as extensive and stronger in the forecast.

What a tasty looking prospect  a repeat of February 2013

[Man With Beard]

I note the 06Z GFS pushes the vortex way, way off the pole. However, it ends up over the N Atlantic. 

Just assuming this run proves true, and it coincides with a neutral or positive AO, what do people think is the likely tropospheric response, both in terms of the PV and potential negative AO?

[bluearmy]

18 minutes ago, Man With Beard said:

I note the 06Z GFS pushes the vortex way, way off the pole. However, it ends up over the N Atlantic. 

Just assuming this run proves true, and it coincides with a neutral or positive AO, what do people think is the likely tropospheric response, both in terms of the PV and potential negative AO?

It's not a great place for nw Europe re a displacement event.  however, given that we saw a kara high beneath the strat vortex a couple of weeks ago, the strat/trop coupling is open to conjecture anyway, 

[ukpaul]

There are pulses of warming throughout from 0h to 384 h as per current GFS RUNS at 10hpa. Is that what he means by extensive?  At the moment it's almost like waiting for an elephant to give birth, not so much a sudden warming as an extensively trailed one.

[nick sussex]

12 minutes ago, bluearmy said:

It's not a great place for nw Europe re a displacement event.  however, given that we saw a kara high beneath the strat vortex a couple of weeks ago, the strat/trop coupling is open to conjecture anyway,

So the PV could just react to any warming by displacing to the worst location! You couldn't make it up! This strat reminds me of Grace Jones at her best! Stroppy, attention seeking and then refuses to go on stage or is 2 hours late!

 

[Recretos]

I would be very careful regarding trop-strat couplings and trop responses and feedbacks and UK cold shots and so on.... Just a friendly reminder. 
06z GFS actually gave an example if a quick response.
 

[mountain shadow]

2 hours ago, nick sussex said:

So the PV could just react to any warming by displacing to the worst location! 

 

I though that was common knowledge by now Nick. The SSW pretty much guarantees that the PV will be displaced from the pole (-AO), what it doesn't guarantee is a -NAO.

The SSW therefore increases the liklihood of proper cold into GB because we know the cold is being shunted equator wards, we still need other drivers to give a Greenland or Scandi high.

[wishingforsnow]

28 minutes ago, mountain shadow said:

I though that was common knowledge by now Nick. The SSW pretty much guarantees that the PV will be displaced from the pole (-AO), what it doesn't guarantee is a -NAO.

The SSW therefore increases the liklihood of proper cold into GB because we know the cold is being shunted equator wards, we still need other drivers to give a Greenland or Scandi high.

That's right, as long as we can eventually get a Scandi or even better, Greenland high of which the building blocks towards achieving one was shown on some model runs in the end, then with a SSW the cold is ours. Whether the building blocks will fall in place in the correct way remains to be seen but hopefully luck will be on our side in order to achieve everything we need for a proper pattern flip. This is something that has been hinted at since the start of winter and I feel like we are getting to the climax point of 'will it happen' especially with the recent cold spell under our belts providing more encouragement that a sustainable change in winter weather pattern is obtainable.

[bluearmy]

ECM op has the strat vortex split by day 10 up to 30hpa and possibly higher.  In general terms at that timescale, the gfs op offers reasonable agreement though without any split.  The ECM seems to be making rather more of the kara ridge high up than gfs op which results in the split forming. Reasonable agreement that the strat vortex will be headed towards Scandinavia which ties in with some of the trop modelling at that timescale. 

[northwestsnow]

58 minutes ago, bluearmy said:

ECM op has the strat vortex split by day 10 up to 30hpa and possibly higher.  In general terms at that timescale, the gfs op offers reasonable agreement though without any split.  The ECM seems to be making rather more of the kara ridge high up than gfs op which results in the split forming. Reasonable agreement that the strat vortex will be headed towards Scandinavia which ties in with some of the trop modelling at that timescale. 

Question of how much residual energy is left across Greenland medium term though Blue.

[Singularity]

1 hour ago, bluearmy said:

ECM op has the strat vortex split by day 10 up to 30hpa and possibly higher.  In general terms at that timescale, the gfs op offers reasonable agreement though without any split.  The ECM seems to be making rather more of the kara ridge high up than gfs op which results in the split forming. Reasonable agreement that the strat vortex will be headed towards Scandinavia which ties in with some of the trop modelling at that timescale. 

Fascinating... thanks for that update. Who to trust more with a stratospheric Kara ridge... not many years ago I'd have said ECM in a heartbeat, these days I'm less sure as the models are closer together in the resolution and strat. levels (as far as I know, anyway).

Edited January 21, 2016 by Singularity

[David Morse]

I'm sure that a SSW event precedes a cold event in the troposphere by 12 days(AVG)? So when looking at the Strat temp and location of the PV at the end of the 12z GFS run you really need to see the trop 12 days after to know if it causes a cold event over NW Europe...

[Abyss]

The 2013 SSW occurred in January and we felt it weather wise that March. If and I emphasis if one was to occur at the beginning of February, would we be waiting until March again to see possible cold or how soon could its effects be felt? I know a SSW doesn't guarantee cold