Stratosphere Temperature Watch 2015/2016

[bluearmy]

the axis of the upper strat vortex later in week 2 is different on the 12z run. more on the traditional asia to canada line rather than the promising looking meridian it showed a few days ago. tbh, the week 2 modelling looks unconvincing other than there will be quite a warming and the vortex will be displaced somewhat. no decent continuity on what happens to the vortex and how consistent the warming will be and whether the vortex is simply displaced or pinched as has been shown on some op runs.

ed needs to do some more eps fishing!

[lorenzo]

Not quite fishing , but a decent heads up, it thought about it on the zonal wind plot last night, this moves things into 'ramp' stages.

30mb on tonight's GFS sees a split over this period also with the vortex pegged to Siberia.

Bit of a change in the last 48 hrs...

Looking at the extent of that and the question of instant and lagged responses -very difficult to second guess things, looks to me though that this impacts right across the column and we are in for a quick hit.

 

 

[Trom]

I'd be surprised  if we get a SSW by the end of Jan/early Feb but I'm  not sure we need it given then the forcing from the trop.  All we need is is the continued trop to strat influence and a bit of fingers crossed if you want cold.  The signs are in place regarding the MJO and the constriction of the PV shown over current runs.  What happens next, if at at all, is like a ball hitting the reds from a snooker break i.e. no guarantee that they end up where you want them.  So a bit of short term pain with the constriction and then who knows?  Certainly the NWP models have been guessing.

Edited January 19, 2016 by Trom
awful spelling

[Swave Snow]

3 hours ago, lorenzo said:

Not quite fishing , but a decent heads up, it thought about it on the zonal wind plot last night, this moves things into 'ramp' stages.

30mb on tonight's GFS sees a split over this period also with the vortex pegged to Siberia.

Bit of a change in the last 48 hrs...

Looking at the extent of that and the question of instant and lagged responses -very difficult to second guess things, looks to me though that this impacts right across the column and we are in for a quick hit.

 

 

A quick hit what's that? lol

Edited January 20, 2016 by Swave Snow

[Weather-history]

ECM zonal winds at 60N is close to going negative on latest chart

http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html

 

[KyleHenry]

23 minutes ago, Weather-history said:

ECM zonal winds at 60N is close to going negative on latest chart

http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html

 

I'll post charts for you.  

 

[chris55]

Nice charts above! Very nearly negative at the top of the atmosphere, and good flux direction at the bottom of the chart. Am I right in thinking we need the negative winds at 10hpa for an official SSW, and not just a 1hpa?

[bluearmy]

The direction of travel is clear there but 60N 10hpa still has positive winds of 25m/s at day 10.  We had some very positive strat charts last winter from ECM op output which never verified at all. However, with decent ncep support, it seems all is not too well with this leviathan of a strat vortex and the current roar (loud though it is) is likely it's last noisy one this season. 

[Interitus]

On 1/18/2016 at 6:33 PM, KyleHenry said:

In short yes, but the exact details of Temperatures/energy are not confirmed. 

What makes this a possible major SSW is longevity of the strong PV and the combination of wave 1 followed by Mountain torque event.

Very exciting to observe.

Once again, where is the mountain torque event?

[Weather-history]

57 minutes ago, bluearmy said:

The direction of travel is clear there but 60N 10hpa still has positive winds of 25m/s at day 10.  We had some very positive strat charts last winter from ECM op output which never verified at all. However, with decent ncep support, it seems all is not too well with this leviathan of a strat vortex and the current roar (loud though it is) is likely it's last noisy one this season. 

Was any research done on the impact on the low pressure anomalies in the Kara Sea region last winter? I seem to recall Dr Cohen mentioning it a few times in his blog. It seem to be a stumbling block that tripped people up.

[chionomaniac]

37 minutes ago, Weather-history said:

Was any research done on the impact on the low pressure anomalies in the Kara Sea region last winter? I seem to recall Dr Cohen mentioning it a few times in his blog. It seem to be a stumbling block that tripped people up.

Not particularly for last year - but we were recently discussing on twitter the importance of the Kara high for AO and NAO blocking events especially when combined with SSW's. Low heights in this region combined with no SSW gave the worst AO/NAO outlook and a strong Kara high combined with an SSW gave a great -ve NAO. The hard work was yet again supplied by the brilliant Ant Masiello. If you go to the tweet chains then you can see a comparison of the years

 

 

 

 

[Recretos]

Thanks to @lorenzo, he just reminded me of the NASA GEOS5 model.

Looks cool, with the nice seen region where the warming is charging from (the positive vertical velocity). We can also see some of the gravity waves. 

 

and regarding the u-wind, its is close to ECM. And also by the wave 1 strength. 

  

height wise, its going for a strong wave 1.

    

 

 

Edited January 20, 2016 by Recretos

[lorenzo]

Here is the latest mountain torque plot from wdt, not there yet.

[Interitus]

41 minutes ago, Recretos said:

Thanks to @lorenzo, he just reminded me of the NASA GEOS5 model.

Looks cool, with the nice seen region where the warming is charging from (the positive vertical velocity). We can also see some of the gravity waves. 

 

 

 

Which pressure level is this Omega chart?

[Recretos]

Darn, forgot to add it. its 10mb.
 

[Nouska]

On ‎1‎/‎20‎/‎2016 at 9:46 AM, chionomaniac said:

Not particularly for last year - but we were recently discussing on twitter the importance of the Kara high for AO and NAO blocking events especially when combined with SSW's. Low heights in this region combined with no SSW gave the worst AO/NAO outlook and a strong Kara high combined with an SSW gave a great -ve NAO. The hard work was yet again supplied by the brilliant Ant Masiello. If you go to the tweet chains then you can see a comparison of the years

Also remembering the research that was linked last winter - to have strongest heights centred over the Taymyr peninsula but most important that those heights extend through all layers of the atmosphere.

100mb    50mb 

Edited January 21, 2016 by Nouska

[KyleHenry]

9 hours ago, Interitus said:

Once again, where is the mountain torque event?

If you follow this link for visual gif of EAMT event 

http://www.americanwx.com/bb/index.php/topic/908-stratosphere-thread/

Series of strong atmospheric  Kelvin waves out of Indian Ocean area have been emitted over this  month, higher AAM. 

If you observe the placement and region of the upcoming energy wave it iminates from Himalayan mountain plateau in turn it becomes a pre cursor to a SSW in upper Stratosphere. 

 

[phil nw.]

The ECM output for yesterday certainly shows the effects over the next 10 days of the top warming gradually downwelling slowing the mean zonal wind speeds.

                         

 

added to the warming at the trop. level,a real squeeze being put on that cold mid-level.It's the closest i have seen  the forecast to a total reversal.

To my untrained eye we should see a switch to a -AO quite soon into February if those zonal wind forecasts verify.Maybe a vortex displacement rather than a split at this stage?

[damianslaw]

Some encouraging posts and signs we may be about to see the polar vortex hit considerably over the latter part of this month, setting up a different northern hemispheric background as we enter February, one far more conducive to producing a colder outlook and more importantly also perhaps a drier more blocked set up. So whilst the immediate outlook looks less than inspiring for anyone who likes cold settled weather, in the background significant building blocks could be emerging towards a very different set up come next month.

 

[Weather-history]

Dr Cohen on his Twitter account says in response to someone that both GFS and Euro are predicting a SSW within 10 days.

Are they? 

[mountain shadow]

11 minutes ago, Weather-history said:

Dr Cohen on his Twitter account says in response to someone that both GFS and Euro are predicting a SSW within 10 days.

Are they? 

Get in.  Lets hope for a quick downwelling.  

The charts come the month end will hopefully start to show up some great charts. 

[feb1991blizzard]

12 minutes ago, Weather-history said:

Dr Cohen on his Twitter account says in response to someone that both GFS and Euro are predicting a SSW within 10 days.

Are they? 

No.

 

 

 

I could understand him saying that the GFS is right at the end of the run, although its not technically an SSW, I think his definition of SSW is that if he thinks its strong enough that he thinks the AO will at some point respond and go negative, he still calls it an SSW,

 

There is some charts that suggest one might not be too far away though on the berlin plots though.

 

 

Edited January 21, 2016 by feb1991blizzard

[Johnp]

A bit worrying that Cohen, one of the so called stratospheric experts doesnt even know what a SSW is?

[ukpaul]

10 minutes ago, Johnp said:

A bit worrying that Cohen, one of the so called stratospheric experts doesnt even know what a SSW is?

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

[Yarmy]

He's certainly pretty bullish:

 

 

 

 

If he posted on here, he'd be chastised for ramping.