Jump to content
Snow?
Local
Radar
Cold?
IGNORED

Stratosphere and Polar Vortex Watch


Paul

Recommended Posts

Posted
  • Location: Abergavenny
  • Location: Abergavenny
1 hour ago, Interitus said:

No simple answer really. With regards to the years mentioned however, 2008/9 featured a roaring vortex at record strength from 4-8th Jan before the SSW. 2009/10 did have an SSW but on February 9th after the main cold spell. 2010/11 had no SSW and a generally stronger than normal strat vortex.

Somewhat puzzling that while conditions are considered in remote influences such the Tropics and Pacific, Atlantic SSTs on the other hand rarely get a mention (indeed didn't feature in the Netweather winter forecast) when they have long been known to directly affect synoptic patterns for the UK and western Europe.

Really good point regarding Atlantic SSTs. For those seeking UK / Euro cold one of the factors you should ideally be looking for is the Warm/Cold/Warm tri-Pole in the North Atlantic. And it isn’t there this winter.

There is always discussion about the Pacific and  MJO signals in the model threads but as you say the Atlantic rarely if ever gets a mention and it should.

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Roznava (Slovakia) formerly Hollywood, Co Wicklow
  • Weather Preferences: continental climate
  • Location: Roznava (Slovakia) formerly Hollywood, Co Wicklow
2 hours ago, DavidS said:

Really good point regarding Atlantic SSTs. For those seeking UK / Euro cold one of the factors you should ideally be looking for is the Warm/Cold/Warm tri-Pole in the North Atlantic. And it isn’t there this winter.

There is always discussion about the Pacific and  MJO signals in the model threads but as you say the Atlantic rarely if ever gets a mention and it should.

Another example is where all the focus is on what happens to the West and NAO, yet no one is looking East, the absence of Gulf of Genoa low, Black See low or, Baltic See low or you can say low pressure activity generated in central Europe is causing permanent record braking temperatures in Europe. Look at this summer how persistent the -NAO was yet Europe had one if its warmest summers ever and records were broken in many countries Tmax. Even next week, UK high for a while used to mean quite a cold central and eastern Europe, now because of lack of low pressure activity the T2M temperatures will just end up above average everywhere in Europe.

  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Longden, Shropshire
  • Location: Longden, Shropshire
8 hours ago, jules216 said:

Another example is where all the focus is on what happens to the West and NAO, yet no one is looking East, the absence of Gulf of Genoa low, Black See low or, Baltic See low or you can say low pressure activity generated in central Europe is causing permanent record braking temperatures in Europe. Look at this summer how persistent the -NAO was yet Europe had one if its warmest summers ever and records were broken in many countries Tmax. Even next week, UK high for a while used to mean quite a cold central and eastern Europe, now because of lack of low pressure activity the T2M temperatures will just end up above average everywhere in Europe.

I think this is more evidence of the effects of climate change.  

Edited by Don
Link to comment
Share on other sites

Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl
11 hours ago, DavidS said:

Really good point regarding Atlantic SSTs. For those seeking UK / Euro cold one of the factors you should ideally be looking for is the Warm/Cold/Warm tri-Pole in the North Atlantic. And it isn’t there this winter.

There is always discussion about the Pacific and  MJO signals in the model threads but as you say the Atlantic rarely if ever gets a mention and it should.

Good point about the tri-pole.. can't think the last time we had one, possibly May 2010 produced one, and its in May when NAO forecasts are made, as there is some correlation these appear again in the winter.

This May brought a significant negative NAO though.. this year has been another puzzle in this respect.. other factors at play?

Would be good to look back at winters with a tripole. I think the 05/06 winter forecast was based on a tri-pole pattern.

Recent winters have seen cold blobs over the N atlantic.

What has been notable since 08/09 I think is the tendency to have to rely on SSW for cold weather, with exception of winter 09/10, and Dec 10. SSW's don't always deliver though as last year taught us, and don't happen every year.. so it must be other factors also at play.. or we just got lucky with the long run of winters in the 60s and also 81-87 that produced at least one lengthy cold/very cold wintry spell. 

Perhaps we need a major volcanic eruption to change things... mmm... the world is due one, the last one being 1991 I think?

 

  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

 

Link to comment
Share on other sites

Posted
  • Location: Teston, Kent (3mls SW of Maidstone)
  • Location: Teston, Kent (3mls SW of Maidstone)
19 minutes ago, Kirkcaldy Weather said:

 

Thanks. Can I just ask in layman's terms what implications this might have here in the UK?

  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Musselburgh, East Lothian; 20m elevation.
  • Weather Preferences: Extremes, preferably thunderstorms, cold and bad weather.
  • Location: Musselburgh, East Lothian; 20m elevation.
13 hours ago, damianslaw said:

Perhaps we need a major volcanic eruption to change things... mmm... the world is due one, the last one being 1991 I think?

I'm not sure about this - I just had a quick look at Wikipedia for the major eruptions of recent geological times, and we don't get Pinatubo-sized events much more than once per century. Of course, we may get one tomorrow, but it wouldn't be particularly surprising at these odds to be waiting another century or more for something big enough to affect world weather.

Link to comment
Share on other sites

Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK
1 hour ago, Kentish Man said:

Thanks. Can I just ask in layman's terms what implications this might have here in the UK?

In laymans terms - warming in the stratosphere could result in a big disruption to the Polar Vortex. The red lines on the graph above show easterly zonal winds in the stratosphere. If that were to happen, the Polar Vortex could be massively displaced/split apart and allow colder air to spill down to the mid latitudes. Think back to the 'beast from the east' cold weather in February 2018, where a similar thing happened.....but every event is different, and impacts on the UK may be as extreme as this, or non existent. It just increases the likelihood of colder weather, but doesn't guarantee it.

Edited by mb018538
  • Like 3
Link to comment
Share on other sites

Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

 

  • Like 7
Link to comment
Share on other sites

Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire

Ventrice has just posted a cryptic tweet (well to my level of understanding at least), which I've added to the twitter thread. Anyone able to explain? Thanks, Griff. 

Link to comment
Share on other sites

Posted
  • Location: Near Worcester
  • Location: Near Worcester
On 14/01/2020 at 22:02, damianslaw said:

Good point about the tri-pole.. can't think the last time we had one, possibly May 2010 produced one, and its in May when NAO forecasts are made, as there is some correlation these appear again in the winter.

This May brought a significant negative NAO though.. this year has been another puzzle in this respect.. other factors at play?

Would be good to look back at winters with a tripole. I think the 05/06 winter forecast was based on a tri-pole pattern.

Recent winters have seen cold blobs over the N atlantic.

What has been notable since 08/09 I think is the tendency to have to rely on SSW for cold weather, with exception of winter 09/10, and Dec 10. SSW's don't always deliver though as last year taught us, and don't happen every year.. so it must be other factors also at play.. or we just got lucky with the long run of winters in the 60s and also 81-87 that produced at least one lengthy cold/very cold wintry spell. 

Perhaps we need a major volcanic eruption to change things... mmm... the world is due one, the last one being 1991 I think?

 

The stratospheric theory is interesting and seems relatively new in terms of discussion of impact

Link to comment
Share on other sites

15 minutes ago, northwestsnow said:

Cohen tweeting about strong PV coupling and postitve AO into Feb.

Fat lady clearing her throat?

Have to see the effect of the Euro/UK/North Atlantic high giving spike in wave 1. Vortex displacement again (as is the norm) but probably no quick change from the strat.

Edited by Interitus
  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

 

  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
  • Weather Preferences: Any Extreme
  • Location: Sheffield South Yorkshire 160M Powering the Sheffield Shield
4 hours ago, northwestsnow said:

Cohen tweeting about strong PV coupling and postitve AO into Feb.

Fat lady clearing her throat?

I think she did that as soon as the zonal flow appeared she's now practicing her chorus.

  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
3 minutes ago, The PIT said:

I think she did that as soon as the zonal flow appeared she's now practicing her chorus.

image.thumb.png.cd7479d8a8aeffd9872be5cbfc5f7fa2.pngimage.thumb.png.feb8bd65910f81dc1c99569c2c56f511.png

She has just gone horse and had to shut up.

  • Like 5
Link to comment
Share on other sites

14 hours ago, Kirkcaldy Weather said:

 

The wave 1 modifies the vortex enough to bring values closer to the range where a SSW has occurred. Taking the GEOS forecast from 15/1 for 24/1, the earliest an SSW has happened from the 10mb zonal wind is 6 days (30th Jan), 10% by 14 days (7th Feb), 20% 17 days (10th Feb)

From 30mb wind earliest 7 days (31st Jan), 10% 10 days (3rd Feb), 20% 21 days.(14th Feb)

From 30mb polar cap temperature earliest  6 days (30th Jan), 10% 7 days (31st Jan), 20% 17 days (10th Feb)

From 50mb polar cap temperature earliest 6 days (30th Jan), 10% 13 days (6th Feb), 20% 19 days (12th Feb)

Note the percentages are not quite absolute chance as not all SSW were immediately preceded by the forecast values forecast for 24/1, it is the percentage of all SSW that were.

Edited by Interitus
  • Like 1
Link to comment
Share on other sites

Posted
  • Location: Kirkcaldy, Fife, Scotland 20m ASL
  • Weather Preferences: Snow,Thunderstorms mix both for heaven THUNDERSNOW 😜😀🤤🥰
  • Location: Kirkcaldy, Fife, Scotland 20m ASL

 

  • Like 2
Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
×
×
  • Create New...