Stratosphere and Polar Vortex Watch 2020

[swfc]

8 hours ago, Howie said:

https://twitter.com/judah47/status/1449735532716691457?t=rTQUPEalSQiQMs9Y2paX0A&s=19 interesting 

Given BA comments I'd suspect the dice are finally balanced within the zonal flow and spv. I'd be of the opinion that maybe early November is the time to be looking at any direction either way

[bluearmy]

8 hours ago, swfc said:

Given BA comments I'd suspect the dice are finally balanced within the zonal flow and spv. I'd be of the opinion that maybe early November is the time to be looking at any direction either way

Tonight’s ec46 of interest - at the moment the near term looks like a reasonably swift recovery in strat zonal flow to average or above on the gefs. 

[Paul_1978]

On 11/10/2021 at 22:55, Catacol said:

Heart of winter looking grim. We are going to need the SSW wildcard again if this modelling is correct. Note - "if."

Am I missing something here as this is an anomaly chart. Thus, pale yellow for example means slightly above average as to what is the norm for those three months; lightest green means slightly below average for those three months. 

Do we not have to see what an "average" chart looks like, and then look at the anomaly chart in the context of that?

Also, this is 3 months in one single graphic, so I don't think we can read too much into it in isolation.

[sebastiaan1973]

2 hours ago, Paul_1978 said:

Am I missing something here as this is an anomaly chart. Thus, pale yellow for example means slightly above average as to what is the norm for those three months; lightest green means slightly below average for those three months. 

Do we not have to see what an "average" chart looks like, and then look at the anomaly chart in the context of that?

Also, this is 3 months in one single graphic, so I don't think we can read too much into it in isolation.

Check the seperate months. I showed them earlier.

[Griff]

Remains below average... 

[bluearmy]

11 minutes ago, Griff said:

Remains below average... 

Just about yes - unconvincing overall. More runs needed ! 

[Griff]

3 minutes ago, bluearmy said:

Just about yes - unconvincing overall. More runs needed ! 

I'm taking it as a positive given what it was showing this time last week, especially as I was expecting worse. 

[blizzard81]

On 14/10/2021 at 21:05, Griff said:

Ecmwf today vs Monday,  

I'm with Griff on this one. These are last week's offerings. The trend is clear and getting better. Of course, we all know things can do an about turn again but all we can comment on is the trend, whether it be good or bad. At the moment it's good so I will bank that for now. 

[SqueakheartLW]

I like the look of the latest CFS runs here

I know they have the bias corrected runs but still. All 4 runs go into a reversal at some point during December

[Frostbite1980]

50 minutes ago, SqueakheartLW said:

I like the look of the latest CFS runs here

I know they have the bias corrected runs but still. All 4 runs go into a reversal at some point during December

It is nice to see however they have the bias corrected ones for a reason. I wish they would do away with the un bias ones because if they are not correct whats the point of showing them

[summer blizzard]

I'd be more bothered about them remaining below 20 on the chart for a sustained period than whether we ssw or not (indeed an early SSW could well see a rebound).

I think it may have been winter 06 that was persistently weak.

Edited October 19, 2021 by summer blizzard

[SqueakheartLW]

Just out of interest and for anyone who may be interested in this. I noticed that the NASA QBO website are now displaying daily QBO data for several layers of the atmosphere from 300hpa right up to 10hpa.

This is the chart the data is for and it is clearly a new addition as I only noticed the new link yesterday and have put the link below for anyone who wants to have a look

https://acd-ext.gsfc.nasa.gov/Data_services/met/qbo/QBO_Singapore_3yr_Uvals_GSFC.txt

[sebastiaan1973]

https://apps.ecmwf.int/webapps/opencharts/products/extended-zonal-mean-zonal-wind?area=nh&base_time=202110210000

 

[Howie]

15 minutes ago, sebastiaan1973 said:

https://apps.ecmwf.int/webapps/opencharts/products/extended-zonal-mean-zonal-wind?area=nh&base_time=202110210000

 

Yikes

[Griff]

26 minutes ago, sebastiaan1973 said:

https://apps.ecmwf.int/webapps/opencharts/products/extended-zonal-mean-zonal-wind?area=nh&base_time=202110210000

 

Not that surprising after the day I've had  

[Don]

1 hour ago, sebastiaan1973 said:

https://apps.ecmwf.int/webapps/opencharts/products/extended-zonal-mean-zonal-wind?area=nh&base_time=202110210000

 

Hmm.....  Oh dear.  Still, just one run and returns to near average to a tad below by early December, so not a complete disaster aye!

[damianslaw]

4 minutes ago, Don said:

Hmm.....  Oh dear.  Still, just one run and returns to near average to a tad below by early December, so not a complete disaster aye!

Weve weak zonal winds now and  an Atlantic ruling the roost.. not sure these tell us anything about what will be happening on the ground. 

[Don]

13 minutes ago, damianslaw said:

Weve weak zonal winds now and  an Atlantic ruling the roost.. not sure these tell us anything about what will be happening on the ground. 

Well, this is true!  You would have thought though, that with weak zonal winds, any Atlantic ruling would be transitory.  However, not always that straightforward!

Edited October 21, 2021 by Don

[syed2878]

3 hours ago, Don said:

Well, this is true!  You would have thought though, that with weak zonal winds, any Atlantic ruling would be transitory.  However, not always that straightforward!

 With our position on the doorstep of the Atlantic it never is straight forward when it comes to UK weather is it is why we all stressing before winter even kicks in I do hope the Strat helps us out a bit this upcoming season though.

[summer blizzard]

One must remember that the polar vortex increases in size through to January so weakness now is not nessesarily enough to push the jet as far south as will be later in winter when their is more cold available.

[Mike Poole]

21 hours ago, damianslaw said:

Weve weak zonal winds now and  an Atlantic ruling the roost.. not sure these tell us anything about what will be happening on the ground. 

The Atlantic is not ruling the roost, it is a slowly passing low pressure, in an otherwise meridional pattern, in my view.

[bluearmy]

11 hours ago, Mike Poole said:

The Atlantic is not ruling the roost, it is a slowly passing low pressure, in an otherwise meridional pattern, in my view.

I think the sudden appearance of standard autumn Atlantic lows against the last few months  has skewed opinion …….  Certainly more autumnal to see a zonal jet but I agree, we revert to meridian all again with Atlantic height rise and troughing somewhere to the east of the ridge.  That’s a v wide envelope btw ….

[bluearmy]

Vertical cross u-mean + EPflux

WWW.WEATHERISCOOL.COM

We have almost a week of reversed zonal flow in the Arctic before a swift recovery propagates down into the lower strat. 

perhaps this is not such a bad thing. A full on reversal down to 60/70N would likely lead to a v strong spv through December which bodes badly for jan/feb prospects for coldies.  Maybe we will see a recovery through November which isn’t strong enough to withstand further wave breaking from the trop and hence the likelihood of the strat leading the trop into a strong pv for the heart of winter is reduced.  

[Don]

1 hour ago, bluearmy said:

Vertical cross u-mean + EPflux

WWW.WEATHERISCOOL.COM

We have almost a week of reversed zonal flow in the Arctic before a swift recovery propagates down into the lower strat. 

perhaps this is not such a bad thing. A full on reversal down to 60/70N would likely lead to a v strong spv through December which bodes badly for jan/feb prospects for coldies.  Maybe we will see a recovery through November which isn’t strong enough to withstand further wave breaking from the trop and hence the likelihood of the strat leading the trop into a strong pv for the heart of winter is reduced.  

I just wonder if later in the winter though, La Nina will have more of an influence and override other signals which may favour cold? 

[bluearmy]

1 hour ago, bluearmy said:

Vertical cross u-mean + EPflux

WWW.WEATHERISCOOL.COM

We have almost a week of reversed zonal flow in the Arctic before a swift recovery propagates down into the lower strat. 

perhaps this is not such a bad thing. A full on reversal down to 60/70N would likely lead to a v strong spv through December which bodes badly for jan/feb prospects for coldies.  Maybe we will see a recovery through November which isn’t strong enough to withstand further wave breaking from the trop and hence the likelihood of the strat leading the trop into a strong pv for the heart of winter is reduced.  

Ecm not quite a bullish with the amount of reversed flow 

Institute of Meteorology - Working Group Atmospheric Dynamics - Zonal Averages of ECMWF analyses and forecasts October 22 2021 12 UTC

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