Stratosphere and Polar Vortex Watch

[Snowy L]

2 minutes ago, chionomaniac said:

GFS 18Z

Appearing at 10hpa too, though weaker. Looks like a top>down warming.

 

Edited January 4, 2018 by Snowy L

[feb1991blizzard]

1 minute ago, chionomaniac said:

GFS 18Z

Was just going to post it along with quoting your post a few days ago touting the 20th as a date!!!

[ItNeverSnowsInWindsor]

What’s the chances of that chart making its way to the 20th ?

[chionomaniac]

9 minutes ago, prolongedSnowLover said:

What’s the chances of that chart making its way to the 20th ?

At the moment it's spotting and confirming trends. Initially we will see a number of runs showing a warming at the end of the run but with some watered down options. If there is any chance of a warming occurring then this will need to get within a reasonable timeframe - definitely within 10 days with cross model and ensemble agreement. Also very much dependent on the trop pattern and the amplitudes of the Scandi and Alaskan blocks.

So very much a watching and waiting game.

[Summer Sun]

 

[Interitus]

13 hours ago, chionomaniac said:

GFS 18Z

However it is of course a wave 1 pattern - wave 2 was briefly evident a couple of days ago -

 

[chionomaniac]

7 minutes ago, Interitus said:

However it is of course a wave 1 pattern - wave 2 was briefly evident a couple of days ago -

 

Yep, But I would still expect the wave 2 to materialise after with the current set up.

[Interitus]

32 minutes ago, Summer Sun said:

 

This fantastic webpage by Professor Andrea Lopez Lang shows details of the vortex from GEFS forecasts like the above and more - http://www.atmos.albany.edu/facstaff/andrea/webmaps/test_GEFSellipse_timeseries.html

Shows nothing out of the ordinary in the foreseeable at the moment, the vortex is elongated at times but on the large side.

Here is some more good stuff from her -

http://www.atmos.albany.edu/facstaff/andrea/webmaps/GEFSellipseFcast_update.html

http://www.atmos.albany.edu/facstaff/andrea/webmaps/realtimeVortex/GFSellipseFcast.html

http://www.atmos.albany.edu/facstaff/andrea/webmaps/GEFSellipseFcast.html

 

[Interitus]

23 minutes ago, chionomaniac said:

Yep, But I would still expect the wave 2 to materialise after with the current set up.

At the moment GFS says unlikely with current set up -

[feb1991blizzard]

Lovely!!!

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2018010512&var=HGT&lev=1mb&hour=384

[ArHu3]

15 minutes ago, ShortWaveHell said:

What’s the general lag of a SSW influencing the Trop? Is there like a rule of thumb for a SSW’s effect ?

they say around 2-3 weeks, last major midwinter ssw was  around 1-1-2013 and winter came the 15th. I guess around the 21st is the latest we would  want to see a ssw, later will just ruin spring

Edited January 5, 2018 by ArHu3

[snowking]

37 minutes ago, feb1991blizzard said:

Lovely!!!

http://www.instantweathermaps.com/GFS-php/showmap-strat.php?run=2018010512&var=HGT&lev=1mb&hour=384

Indeed! Getting up to a very toasty 10c at 1mb by the end of the run

Of course we know from history that the GFS Op has a tendency to post phantom warnings towards the end of its runs but will be good to monitor this and hopefully reel it in like we did back in Dec 2012/Jan 2013

Interesting times and not unexpected given the advertised tropospheric pattern (despite the nuances around the exact surface conditions for our tiny little island) as highlighted by Ed some days ago nowadays.

@ArHu3 - of course, March 2013 springs to mind...

Edited January 5, 2018 by snowking

[feb1991blizzard]

1 minute ago, snowking said:

Indeed! Getting up to a very toasty 10c at 1mb by the end of the run

Of course we know from history that the GFS Op has a tendency to post phantom warnings towards the end of its runs but will be good to monitor this and hopefully reel it in like we did back in Dec 2012/Jan 2013

Interesting times and not unexpected given the advertised tropospheric pattern (despite the nuances around the exact surface conditions for our tiny little island) as highlighted by Ed some days ago now.

Is the red line in positive territory yet on the mountain torque charts? that's what I always look for on an over the top warming plus poleward EP flux.

[Paul_1978]

26 minutes ago, ShortWaveHell said:

What’s the general lag of a SSW influencing the Trop? Is there like a rule of thumb for a SSW’s effect ?

Well that chart is at T+384 for a start, then there’s the lag time once it gets to 0 hours, which therefore  = a long time before we see the effects! Joking aside, probably into early Feb?

[Glacier Point]

Time perhaps to dig these out...

I think a lot of the tropospheric response is related to how predisposed the polar field is to blocking signal from above.

2010 - very rapid response.

2006 - more classical Baldwin and Dunkerton

Not a done deal though, although hemispheric pattern beginning to look very much like the precursor to wave 2 weakening of the vortex.

 

Edited January 5, 2018 by Glacier Point

[chionomaniac]

15 minutes ago, Glacier Point said:

Time perhaps to dig these out...

I think a lot of the tropospheric response is related to how predisposed the polar field is to blocking signal from above.

2010 - very rapid response.

2006 - more classical Baldwin and Dunkerton

Not a done deal though, although hemispheric pattern beginning to look very much like the precursor to wave 2 weakening of the vortex.

 

Exactly, thanks Stewart. From what I have learnt there is the classic slow downwelling response but ( especially) in a wave 2 scenario there can also be an almost immediate trop response if the vortex is split well enough. Feb 2009 the classic case of this.

[comet]

26 minutes ago, Glacier Point said:

Time perhaps to dig these out...

I think a lot of the tropospheric response is related to how predisposed the polar field is to blocking signal from above.

2010 - very rapid response.

2006 - more classical Baldwin and Dunkerton

Not a done deal though, although hemispheric pattern beginning to look very much like the precursor to wave 2 weakening of the vortex.

 

We only have to look at the strat charts from Instant weather maps, Berlin etc to see that is happening already. Hence the more amplified northern hemisphere profile with a split up to 30mb.

[lorenzo]

Relevant timelines to throw this in the mix also from Garfinkel

In this study, we expand on these results and demonstrate a statistically significant connection between the MJO and the stratospheric polar vortex, and subsequently the tropospheric NAM, at lags exceeding a month.

[lorenzo]

Tripathi et al is the natural evolution for the next paper - with Matthewman, this demonstrates predictabilty vs prognosis. Glosea caught sw event at 32 days, although over last three seasons differing outcome.

What it has though is longest lead in any model.

 

[feb1991blizzard]

Nice attack on the PV right at the top on GFS 12z although looks like wave 1.

[chionomaniac]

On 1/5/2018 at 12:53, Interitus said:

However it is of course a wave 1 pattern - wave 2 was briefly evident a couple of days ago -

 

Starting to shape up to a wave 2 warming pattern now as expected, though very early days.

 

[Dennis]

On 10HPA a very quick drop in zonal winds

[ArHu3]

16 minutes ago, Dennis said:

On 10HPA a very quick drop in zonal winds

GFS does that often towards the end of a run, overestimating the slowdown, usually a correction follows after 1 or 2 days but let's hope it's right this time 

[Dennis]

3 minutes ago, ArHu3 said:

GFS does that often towards the end of a run, overestimating the slowdown, usually a correction follows after 1 or 2 days but let's hope it's right this time 

yes hope also some good signs - end december we see better warmings in strato - so the runs have started for next weeks

[Weather-history]

Why is the south polar vortex so active in mid summer?

Imagine this chart in summer in the north polar region?