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Stratosphere and Polar Vortex Watch


Paul

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Posted
  • Location: Weymouth, Dorset
  • Location: Weymouth, Dorset
4 hours ago, knocker said:

 

Something I've just learnt from the chart above. So we've never (well, between 1979 and now at least) had an official SSW appear anytime between the dates of 22nd December to 30th December inclusive. These dates are exclusively U westerly! Ties in of course with typical peak VI period but still surprising that in 40 years there hasn't been at least one occasion.

Edited by s4lancia
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9 hours ago, knocker said:

 

First tweet is part of an interesting conversation whereby it turns out that the familiar Hannah Attard charts for 65°N also exist for 60°N, just change the url from 65N to 60N -

 

http://www.atmos.albany.edu/student/hattard/realtime/u_60N_10hpa.png

u_60N_10hpa.png

http://www.atmos.albany.edu/student/hattard/realtime/u_60N_10hpa_gefs.png

u_60N_10hpa_gefs.png

http://www.atmos.albany.edu/student/hattard/realtime/u_60N_10hpa_gefs.png

Second tweet timely for early nacreous cloud potential, as forecasts push the coldest vortex temperatures in our direction at various points in the next couple of weeks -

5a1d1c98db033_NH_TMP_30mb_04817112800.thumb.gif.ca6623c2c93dc83764ff4589f7823959.gif

 

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6 hours ago, s4lancia said:

Something I've just learnt from the chart above. So we've never (well, between 1979 and now at least) had an official SSW appear anytime between the dates of 22nd December to 30th December inclusive. These dates are exclusively U westerly! Ties in of course with typical peak VI period but still surprising that in 40 years there hasn't been at least one occasion.

Maybe, however it turns out with only 4 SSW in that time, totalling 19 days duration, that it would be impossible for all December days to have had reversed zonal winds.

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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
1 hour ago, bluearmy said:

Berlin zonal charts show a very benign strat top to bottom north of 60 later on. U wind below 10m/s right up to 7hpa. 

Thats good news Blue- those zonal winds clearly quite benign (great description) meaning all things being equal we shouldn't be seeing an uber PV like last December- sorry to ask but what were we looking at zonal winds wise early Dec last year?

Edited by northwestsnow
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Posted
  • Location: Netherlands close to the coast
  • Location: Netherlands close to the coast
10 minutes ago, northwestsnow said:

Thats good news Blue- those zonal winds clearly quite benign (great description) meaning all things being equal we shouldn't be seeing an uber PV like last December- sorry to ask but what were we looking at zonal winds wise early Dec last year?

Record low zonal winds late November, early December ?

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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
Just now, ArHu3 said:

Record low zonal winds late November, early December ?

Oh dear, i didn't realize that- thanks :)

I was under the impression the zonal winds shot up early December ..

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Posted
  • Location: st albans
  • Location: st albans
14 minutes ago, northwestsnow said:

Oh dear, i didn't realize that- thanks :)

I was under the impression the zonal winds shot up early December ..

2A241C22-CFE8-49B2-9DAF-B0EF24F76558.thumb.jpeg.eaf417e0b6c52a4131accb6eee56f29b.jpeg

We had strong wave 1 displacement until early Dec. Then it wained and whoosh 

621B0487-5E25-4518-9758-315E35E80E3B.thumb.jpeg.5b0c802f4c9f93742b39c62eeff38667.jpeg

Edited by bluearmy
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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
6 minutes ago, bluearmy said:

2A241C22-CFE8-49B2-9DAF-B0EF24F76558.thumb.jpeg.eaf417e0b6c52a4131accb6eee56f29b.jpeg

We had strong wave 1 displacement until early Dec. Then it wained and whoosh 

621B0487-5E25-4518-9758-315E35E80E3B.thumb.jpeg.5b0c802f4c9f93742b39c62eeff38667.jpeg

Well at face value it looks different to last December in that the zonal winds are not expected to shoot up within the next 10 days..

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Posted
  • Location: frome somerset 105m ABSL,
  • Weather Preferences: cold snow, thunderstorms
  • Location: frome somerset 105m ABSL,

Can someone explain what this means, sorry still learning 

0290A1F8-53FC-4B42-972E-AA773A9644DD.jpeg

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Posted
  • Location: st albans
  • Location: st albans
44 minutes ago, fromey said:

Can someone explain what this means, sorry still learning 

0290A1F8-53FC-4B42-972E-AA773A9644DD.jpeg

its a mean charts covering days 11/15 of ecm ens mean height anomalies away from the climatological norm

the reds show where the high height deviation is the highest and the blues where the low height deviation is largest. hence you can deduce that the azores high is likely to be a little stronger than it normally would be which should mean a pretty strong ridge there. there is a cross polar ridge from Alaska to Siberia and whilst Greenland has some oranges, we would usually expect blues there so the model doesn't see much of a ridge likely there. hence, the azores anomaly is less intense than the Greenland but the actual result is much higher heights likely near the azores than Greenland.

note the very strong eastern usa anomaly - that will promote a strong atlantic jet which is more than likely a big factor in the met offices prediction of a return to mobility by mid december 

these are upper patterns and not surface features. at this range surface mean charts trend towards climatological norm apart from where we see hugely anomalous features such as the Alaskan ridge

Edited by bluearmy
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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

Last ECM forecasts continue to keep a lid on mean zonal wind speeds and graph showing some warming now at middle/upper levels.

fluxes.giftemps.gif

Wave action continuing to do the job in keeping the vortex disturbed.Day 10 profile of zonal wind forecast with height

ecmwfzm_u_f240.gif

Who knows where this may lead us but this is quite a different start to Winter.  

Edited by phil nw.
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Posted
  • Location: Netherlands close to the coast
  • Location: Netherlands close to the coast
1 hour ago, phil nw. said:

Last ECM forecasts continue to keep a lid on mean zonal wind speeds and graph showing some warming now at middle/upper levels.

fluxes.giftemps.gif

Wave action continuing to do the job in keeping the vortex disturbed.Day 10 profile of zonal wind forecast with height

ecmwfzm_u_f240.gif

Who knows where this may lead us but this is quite a different start to Winter.  

Weren't we looking at something similar last year, with a moribund vortex predicted to split (by the models) which suddenly in 10 days or so went to almost record strength 

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Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl
1 hour ago, ArHu3 said:

Weren't we looking at something similar last year, with a moribund vortex predicted to split (by the models) which suddenly in 10 days or so went to almost record strength 

Yes iirc a big uptick in zw around mid-December.We wait with bated breath to see if this happens again i guess..

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Posted
  • Location: Netherlands close to the coast
  • Location: Netherlands close to the coast
19 minutes ago, phil nw. said:

Yes iirc a big uptick in zw around mid-December.We wait with bated breath to see if this happens again i guess..

See @Summer Sun 's post right below yours

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Posted
  • Location: st albans
  • Location: st albans

new ec op less sharp Alaskan ridge in the trop and also the strat which means the zonal flow would less impressive re late on negatives 

the trop imprint right up to 10 hpa shows the trop currently wearing the trousers !  How long will that last ? 

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Posted
  • Location: Coniston, Cumbria 90m ASL
  • Weather Preferences: wintry
  • Location: Coniston, Cumbria 90m ASL
31 minutes ago, bluearmy said:

new ec op less sharp Alaskan ridge in the trop and also the strat which means the zonal flow would less impressive re late on negatives 

the trop imprint right up to 10 hpa shows the trop currently wearing the trousers !  How long will that last ? 

The trop does seem to be hanging on to the power, not very up on these things but usually the trop and strat would have coupled up by this stage in the year, wouldn't they? 

Are there any years we are aware of where the two never did connect and what was the winter like if that happened? 

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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
37 minutes ago, bluearmy said:

new ec op less sharp Alaskan ridge in the trop and also the strat which means the zonal flow would less impressive re late on negatives 

the trop imprint right up to 10 hpa shows the trop currently wearing the trousers !  How long will that last ? 

I'm beginning to wonder if the PV is going to be getting its act together soonish Blue- GEFS seems keen to increase zonal winds as we move through December..

i have replied to your post in the MO thread as im getting the feeling we could be on the cusp of a January 1984 pattern whereby the jet powers up but on a nw/se axis meaning PM potential, at least for the 1st half of the month :)

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