Stratosphere Temperature Watch 2015/2016

[BLAST FROM THE PAST]

I've heard that Upper SSW timed for 20-23 Jan transferring to Lower SSW 27-30 Jan

 

BFTP

[chionomaniac]

1 minute ago, BLAST FROM THE PAST said:

I've heard that Upper SSW timed for 20-23 Jan transferring to Lower SSW 27-30 Jan

 

BFTP

There is no such thing as upper or lower SSW's? An SSW is defined as a reversal of mean zonal mean winds at 60ºN and 10hPa. Perhaps something has been lost in translation?

[northwestsnow]

I guess this thread is last chance saloon really.

Its been a dreadful winter if truth be told,another winter with an ultra strong PV in the wrong place for us poor coldies.

Can it be brought down,before its too late?

[Recretos]

here is a "super-sized" comparison between multiple GEFS runs, which I will later use to verify the GEFS in strat dynamics, to see if there is any bias going on. 

 

We can see that the ens member 7 is the lowest at 144h, and eventually ends in an SSW. And on the other hand we have member 11, which is the highest at 144h, and eventually also in the end winds up as the highest. If we compare them, we can see how the ens 7 actually has a stronger wave2 hidden in the forecast already at 144h. both, compared to the member 11 and GFS. 

 

But comparing ens 11 and GFS, we can see that the ens 11 also has a bit stronger wave2 and wave1 (if you look at heights), and it moves the vortex a bit less to the siberian, unlike the GFS which has a weaker wave2 and moves the vortex a nit more towards siberia. 

Edited January 14, 2016 by Recretos

[Faronstream]

40 minutes ago, northwestsnow said:

I guess this thread is last chance saloon really.

Its been a dreadful winter if truth be told,another winter with an ultra strong PV in the wrong place for us poor coldies.

Can it be brought down,before its too late?

Last Winter was worse than this,  really Cold air is now over most Scandianvia for the last 2 weeks and temperature drops even in central Europe

I might be wrong, but temperatures around 6-9 celcius is normal over South UK in Jan?

 

[Interitus]

10 hours ago, chionomaniac said:

There is no such thing as upper or lower SSW's? An SSW is defined as a reversal of mean zonal mean winds at 60ºN and 10hPa. Perhaps something has been lost in translation?

But as you know that Charlton & Polvani metric is but one of many definitions - https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxzdHJhdG9zcGhlcmljd2FybWluZ3N8Z3g6MjJkZmUzY2M3ZmVkYjhhMA

I don't believe SPARC have come to an agreement as yet so there is not one clear definition. As the warmings/wind speed changes do work down through the vortex over several days it may be more interesting to know the source of BFTPs info.

[chionomaniac]

1 minute ago, Interitus said:

But as you know that Charlton & Polvani metric is but one of many definitions - https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxzdHJhdG9zcGhlcmljd2FybWluZ3N8Z3g6MjJkZmUzY2M3ZmVkYjhhMA

I don't believe SPARC have come to an agreement as yet so there is not one clear definition. As the warmings/wind speed changes do work down through the vortex over several days it may be more interesting to know the source of BFTPs info.

Yes - but until any new definition is agreed on that is pretty much the accepted definition. And anyway in any of the other definitions I have not ever come across upper and lower SSWs.

[BLAST FROM THE PAST]

10 hours ago, chionomaniac said:

There is no such thing as upper or lower SSW's? An SSW is defined as a reversal of mean zonal mean winds at 60ºN and 10hPa. Perhaps something has been lost in translation?

I'll take your word C on that as certainly not my field.  Maybe that source has it wrong, it quotes 5mb for upper and between 70-50mb lower? 

 

BFTP

[Recretos]

You two are confusing the upper and lower stratosphere (which is actually meant) with upper and lower SSW (just a misunderstanding) which does not even exist so to speak
 

[Interitus]

7 minutes ago, chionomaniac said:

Yes - but until any new definition is agreed on that is pretty much the accepted definition. And anyway in any of the other definitions I have not ever come across upper and lower SSWs.

It may be the most common definition and one I regularly use, but clearly as the Butler et al link shows, the number of authors that have used different metrics means that it isn't 'the accepted definition'.

What happened last January? As I posted previously there was a very significant warming with a few record values in the MERRA data, but there was no 10mb 60°N reversal had to class it as a 'minor warming'. But from Judah Cohen's AER blog of 04/01/16 -

Quote

As we have been discussing in the blog the stretched and elongated polar vortex predicted for the first half of January is very similar to the configuration of the polar vortex of the past two January’s.  Though in January 2014 no SSW occurred while in January 2015 a significant SSW occurred with record warm temperatures in the polar stratosphere.

The 10mb criteria for example is an artefact from when the only insight was radiosonde data. Now with satellite data, LiDAR, high top models etc there is no reason why they shouldn't be classified anywhere from the stratopause downwards. Alongside the search for a common definition, the SSW atlas aims to record SSWs in much greater depth including of altitudes involved and downwelling

http://www.esrl.noaa.gov/csd/reviews/2015/presentations/61Butler.pdf

[Gazza H]

The serious warming I'm seeing on the GFS models keep pushing out further in towards February, but this tweet has given renewed hope.

[KyleHenry]

Has any one got a date for last Canadian warming event? 

Up coming MT event in Asia, it hyper contracts the PV towards Europe.

With this synoptic pattern, is this required for CW to occur with a Rockies MT event?

[feb1991blizzard]

The GFS FI charts show the best displacement right from 1mb down to 10mb yet this season and the warming if anything at 1mb is gaining strength at the end of the run, very interesting I think.

Edited January 16, 2016 by feb1991blizzard

[Snowman.]

37 minutes ago, feb1991blizzard said:

The GFS FI charts show the best displacement right from 1mb down to 10mb yet this season and the warming if anything at 1mb is gaining strength at the end of the run, very interesting I think.

https://gyazo.com/771c408a5339b2436caf80f718f65be0

https://gyazo.com/e0aee5bb5e5af41710fdf8af08b5f017

GFS ends with a 29.4 max at 1mb.

Feb continues to look interesting.

[feb1991blizzard]

Just now, SN0WM4N said:

https://gyazo.com/771c408a5339b2436caf80f718f65be0

https://gyazo.com/e0aee5bb5e5af41710fdf8af08b5f017

GFS ends with a 29.4 max at 1mb.

Feb continues to look interesting.

Yes, I would have posted the charts myself but they disappear when I do them so I just describe them now.

[Snowman.]

3 minutes ago, feb1991blizzard said:

Yes, I would have posted the charts myself but they disappear when I do them so I just describe them now.

Little tool called gyazo allows you to highlight an area on yourscreen and take a screenshot then uploads it to the web for copying, saving etc.

https://gyazo.com

 

[feb1991blizzard]

Just now, SN0WM4N said:

Little tool called gyazo allows you to highlight an area on yourscreen and take a screenshot then uploads it to the web for copying, saving etc.

https://gyazo.com

 

Thanks.

[Singularity]

Another view of the 12z GFS det. warming. The vortex looks distressed to say the least!

[lorenzo]

Couple of the Berlin plots from this morning. Decent wave activity across the strat. u wind peaking at D6 then easing off at D10. Heat flux at 30hPa caught the eye on the fluxes.

Need to send @chionomaniac  fishing on twitter again for the ECM EPS view of things !

[Mucka]

I will just leave this here for you strat guys n gals.

[Spah1]

84hrs before Mucka's 

 

[bluearmy]

Yesterday's Berlin data in line with that posted by tony above. 

certainly appears that we are approaching a crescendo in the upper strat as winds reach 90m/s around 3hpa. Probably the strongest of the season before they suddenly fall away.  the drop off is huge within a short period of time but flow at 30hpa is still above my general average of 30 m/s at day 10.  Wave 1 gepot at day 10 predicted to be largest of the season also. I expect we will see some marked vortex displacement post day 10 as advertised by the gfs op runs. 

 

[KyleHenry]

As you say Bluearmy, peak strength at 90m/s then a dissolution to 40m/s from wave 1. 

 

The GFS follows wave 1 with an EAMT event/SSW in quick succession at months end. 

If GFS is correct with the double phase action, then wave 1 pins PV down and allows EAMT/SSW to dominate PV and in conjunction with its natural decay.

Demoralisation to jubilation is a better route.

 

 

[Snowman.]

GEFS Ensembles don't look nearly as strong as today's OP runs however a good percentage have the vortex beaten into submission with many looking like the chart below.

SSW or not the vortex appears to be on the defence against persistent wave 1.

[lorenzo]

GFS 06z continues to do it's torch thing and always seems to deliver the most progressive projections, a double hit towards the end of the run today. These from 29th then 02nd of Feb. Just to compare - also the vortex as is today. It's a big old shove.

Looking at how NASA views conditions we can see the u wind acceleration as noted above, shows on the latitude plot and also peaking around the 22 on the GEFS Ensemble plot. We still have a couple of troopers going for full, classic wmo definition, SSW.

Heat Flux across projected across all levels on the first image here, then strong forecasts in play at 10 and 30 hPa.

Temperatures - just coming into view on the 70-90 plot, decent impact at 30hPa for first time.

Frictional torque starting an upward trend and will lead the MT event, I wonder if the GEFS outlook will alter in a similar manner to November where it projected the fall through 8/1 and did a sharp right turn cycling back across the Nino base states.

Still a good fortnight away from the projected timings showing the largest vortex hit of the season, an interesting week ahead to see how the MT delivers.