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Stratosphere and Polar Vortex Watch


Paul

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Posted
  • Location: Yarm , Middlesbrough
  • Weather Preferences: snow
  • Location: Yarm , Middlesbrough

are we talking a potnetial  SSW in late Feb that may effect the weather in UK  what 3 weeks later in late March 

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Posted
  • Location: Longden, Shropshire
  • Location: Longden, Shropshire
54 minutes ago, Doctor96 said:

are we talking a potnetial  SSW in late Feb that may effect the weather in UK  what 3 weeks later in late March 

I think that’s what happened in 2008, which lead to a white Easter, followed by cold weather into April.

Edited by Don
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Posted
  • Location: Liverpool - 23m ASL
  • Weather Preferences: Cold, snowy winters and hot, sunny summers!
  • Location: Liverpool - 23m ASL
2 hours ago, Don said:

I think that’s what happened in 2008, which lead to a white Easter, followed by cold weather into April.

March 2013 was exceptional also. (Though I think the SSW that year was in January)

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl
3 hours ago, Doctor96 said:

are we talking a potnetial  SSW in late Feb that may effect the weather in UK  what 3 weeks later in late March 

3 weeks later would be mid March. SSW's can have sudden effects as happened in early Feb 09 but also slow long term effects as happened in Feb/March 13. In average I think the effects are about 3 weeks later.

Would not at all be surprised to see much colder synoptics surface in March, with perhaps some cold stirrings by late February.

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Posted
  • Location: Longden, Shropshire
  • Location: Longden, Shropshire
45 minutes ago, weatherguy said:

March 2013 was exceptional also. (Though I think the SSW that year was in January)

Yes, the 2013 SSW occurred in early January and did actually have a rapid effect, leading to a fairly prolonged cold spell through mid January.  However, the cold relented by the end of the month and was 'on and off' through February, but come March, strong northern blocking really did set in with a vengeance!  April, May and June were all colder than average but a major flip took place at the beginning of July, which turned out to be a hot month, marking the end of a long run of below average months and the colder 2007-2013 period!  We haven't really had a sustained cold period since.

Edited by Don
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Posted
  • Location: Mytholmroyd, West Yorks.......
  • Weather Preferences: Hot & Sunny, Cold & Snowy
  • Location: Mytholmroyd, West Yorks.......

Could we not be seeing the first stirring of the 'final warming' being forecast with this laste Jan event merely the warm up to that Final Warming?

IIRC we have seen late Feb Final Warnings over recent years have we not?

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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
15 hours ago, Don said:

Yes, the 2013 SSW occurred in early January and did actually have a rapid effect, leading to a fairly prolonged cold spell through mid January.  However, the cold relented by the end of the month and was 'on and off' through February, but come March, strong northern blocking really did set in with a vengeance!  April, May and June were all colder than average but a major flip took place at the beginning of July, which turned out to be a hot month, marking the end of a long run of below average months and the colder 2007-2013 period!  We haven't really had a sustained cold period since.

2015 had 5 in a row, 2019 had 5 but not consecutive.

Only 2008, 2010, 2012 and 2013 saw 6 or more 2008 and 2010 had 9.

2 hours ago, Gray-Wolf said:

Could we not be seeing the first stirring of the 'final warming' being forecast with this laste Jan event merely the warm up to that Final Warming?

IIRC we have seen late Feb Final Warnings over recent years have we not?

Only once in 2016, the result of the strong El Niño.

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Posted
  • Location: chellaston, derby
  • Weather Preferences: The Actual Weather ..... not fantasy.
  • Location: chellaston, derby
2 hours ago, Dennis said:

attention to start Febr : ssw looks coming in

 

image.thumb.png.440d0c161b342870c2c810b3bfb8c7e2.pngimage.thumb.png.61d685c168fd4a1ca2ccb06c07f7b3de.png

 

 

Sorry, i cant read those thumbnails, and magnifying them doesnt change their size either.

 

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On 18/01/2020 at 10:12, bluearmy said:

Definitely reversed at the top

looked like it wasn’t quite below 2hpa 

1D45A1A9-43BE-428A-98B2-3CCBEF021D76.thumb.jpeg.197ee5b3212d59e534341b9df4f18daa.jpeg

To update, this 18/01 00z is a bit of an outlier at the moment, there hasn't been a reversal in the 24 runs since, clustering of the windspeed graph shows that reductions are struggling to get inside the 10-12 day reliable timeframe -

70858536_1mbZMZW.thumb.png.b2c3097d102e22840bbcc15493433d35.png

Edited by Interitus
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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
3 hours ago, DavidS said:

Yep, GEFS going for a reversal

 

20C83EE2-4D88-4D43-AE2C-3343F648CEDF.png

Only 2 members but its a start, would like to see CFS going for it more as they have in the past usually been aggressive with SSW's

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Posted
  • Location: Abergavenny
  • Location: Abergavenny
20 minutes ago, feb1991blizzard said:

Only 2 members but its a start, would like to see CFS going for it more as they have in the past usually been aggressive with SSW's

Yes agreed, the post should have mentioned that it was some gefs members. The mean doesn’t take it to a reversal....yet.

The 6z GFS is still going for the strat warm.

 

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Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)

Definite trend downwards starting to show in GEFS in early Feb, some members going negative, but we've been down this garden path before in December at that range, need to get into the reliable to start getting interested

1518644102_u_65N_10hpa_gefs(1).thumb.png.2ab6042eb41771edab05440672f38a82.png

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.
14 minutes ago, Nick F said:

Definite trend downwards starting to show in GEFS in early Feb, some members going negative, but we've been down this garden path before in December at that range, need to get into the reliable to start getting interested

 

To be honest though i was never quite on board in December, it never looked quite right, added to the fact that we have only just started using the GFS op for this purpose so its inherent biases are not yet fully understood, i am more hopeful with this upcoming event but concerned about the timeframe, also will the displacement SSW be enough to influence the trop favourably? It does displace the SPV into a favourable position but would we require a subsequent split to really have influence and also if we did get a split then where would the daughter vortices go?, the one thing on our side though with it being late in season is it might only need a significantly weakened stratospheric vortex in order for the tropospheric vortex to be able to do more of what it wants with the usual seasonal wavelength pattern changes late Feb.

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Posted
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
  • Location: Caterham-on-the-hill, Surrey, 190m asl (home), Heathrow (work)
2 hours ago, feb1991blizzard said:

To be honest though i was never quite on board in December, it never looked quite right, added to the fact that we have only just started using the GFS op for this purpose so its inherent biases are not yet fully understood, i am more hopeful with this upcoming event but concerned about the timeframe, also will the displacement SSW be enough to influence the trop favourably? It does displace the SPV into a favourable position but would we require a subsequent split to really have influence and also if we did get a split then where would the daughter vortices go?, the one thing on our side though with it being late in season is it might only need a significantly weakened stratospheric vortex in order for the tropospheric vortex to be able to do more of what it wants with the usual seasonal wavelength pattern changes late Feb.

Yes, this slowing of zonal winds certainly seems to have more mileage this time round, plus some of the EPS members in the 10-15 day range have been showing a reversal lately. Seasonal weakening of SPV would be expected as we head through Feb too, which will help. Then if a major SSW occurs we need to hope the response is quick and favours HLB that would position favourably to bring sustained cold to the UK. Lots of hurdles to get over, that’s after we do get a reversal in the bag!

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Posted
  • Location: Live in NW Kent by the Thames & work in SE London
  • Weather Preferences: Snowy November to March and Sunny and warm April to October
  • Location: Live in NW Kent by the Thames & work in SE London
1 hour ago, Nick F said:

Yes, this slowing of zonal winds certainly seems to have more mileage this time round, plus some of the EPS members in the 10-15 day range have been showing a reversal lately. Seasonal weakening of SPV would be expected as we head through Feb too, which will help. Then if a major SSW occurs we need to hope the response is quick and favours HLB that would position favourably to bring sustained cold to the UK. Lots of hurdles to get over, that’s after we do get a reversal in the bag!

And add to this the QBO now going Easterly ❄☃️

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Posted
  • Location: Longden, Shropshire
  • Location: Longden, Shropshire
On 23/01/2020 at 14:49, summer blizzard said:

2015 had 5 in a row, 2019 had 5 but not consecutive.

 

Good point.  I think 2015 was overshadowed by that horrifying December!

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Posted
  • Location: Roznava (Slovakia) formerly Hollywood, Co Wicklow
  • Weather Preferences: continental climate
  • Location: Roznava (Slovakia) formerly Hollywood, Co Wicklow

Split at 10hPa on GFS lala land

anim_zxq4.gif

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Posted
  • Location: Abergavenny
  • Location: Abergavenny
51 minutes ago, jules216 said:

Split at 10hPa on GFS lala land

anim_zxq4.gif

The GFS has been showing this warming for several days now, with each run a variation on a theme. This is the first split we’ve seen, albeit in deep FI.

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