Jump to content
Snow?
Local
Radar
Cold?
IGNORED

Stratosphere temperature watch - 2016/17


Paul

Recommended Posts

Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)
3 minutes ago, blizzard81 said:

Must admit I am confused about the mixed messages this evening with regards to the strat. Sounds like there has been a downgrade. How much of a downgrade is this?

There's still a mighty reversal of the zonal winds but GFS now doesn't show that reaching as far down as 10 hPa at 60*N, in fact not even close enough to reverse the wind at all let alone get it to -10 m/s.

Being as far ahead in time as it is, it's too early to know if this is a genuine trend toward a shortfall or a 'wobble'.

 

If the MJO remains more active than the models currently project for week 2 then this could change the game in yet more ways although I think it would be too late to help with this particular SSW attempt given typical lag times for propagation of amplification through the troposphere and then any vertical wave flux that's achieved. Knowing our luck we'll see a SSW right at the end of winter and have to endure another cold March :rolleyes::laugh:

  • Like 2
Link to comment
Share on other sites

Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
2 minutes ago, Singularity said:

There's still a mighty reversal of the zonal winds but GFS now doesn't show that reaching as far down as 10 hPa at 60*N, in fact not even close enough to reverse the wind at all let alone get it to -10 m/s.

Being as far ahead in time as it is, it's too early to know if this is a genuine trend toward a shortfall or a 'wobble'.

 

If the MJO remains more active than the models currently project for week 2 then this could change the game in yet more ways although I think it would be too late to help with this particular SSW attempt given typical lag times for propagation of amplification through the troposphere and then any vertical wave flux that's achieved. Knowing our luck we'll see a SSW right at the end of winter and have to endure another cold March :rolleyes::laugh:

Thank you for your reply :) I must admit, unlike the zonal winds, I am getting that sinking feeling about this winter. 

Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans

The ec op run has some fairly marked continuity issues with previous run and given that the strat is usually fairly good in that regard, especially higher up, I am a little confused. 

Maybe the sudden influx of high temps into the polar field is playing havoc with the usually consistent modelling

would be good if we knew about the glosea view but alas ........

 

Link to comment
Share on other sites

Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
11 minutes ago, bluearmy said:

The ec op run has some fairly marked continuity issues with previous run and given that the strat is usually fairly good in that regard, especially higher up, I am a little confused. 

Maybe the sudden influx of high temps into the polar field is playing havoc with the usually consistent modelling

would be good if we knew about the glosea view but alas ........

 

What is the difference from the previous run BA? Are you referring to the ecm trop run?

Edited by blizzard81
Link to comment
Share on other sites

Posted
  • Location: Stroud, Gloucestershire
  • Weather Preferences: Extreme!
  • Location: Stroud, Gloucestershire
32 minutes ago, blizzard81 said:

So are the zonal winds no longer falling off a cliff? Is this graph now outdated?

That's for 1hpa. Right at the very top of the strat, the question is can we see that reversal downwell to 30/10hpa (at 60n)

Link to comment
Share on other sites

Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
Just now, chris55 said:

That's for 1hpa. Right at the very top of the strat, the question is can we see that reversal downwell to 30/10hpa (at 60n)

I see,  many thanks for that Chris

Link to comment
Share on other sites

Posted
  • Location: Stroud, Gloucestershire
  • Weather Preferences: Extreme!
  • Location: Stroud, Gloucestershire
17 minutes ago, bluearmy said:

The ec op run has some fairly marked continuity issues with previous run and given that the strat is usually fairly good in that regard, especially higher up, I am a little confused. 

Maybe the sudden influx of high temps into the polar field is playing havoc with the usually consistent modelling

would be good if we knew about the glosea view but alas ........

 

Alas, Ian needs to drop a subtle tweet ;) 

Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans
18 minutes ago, blizzard81 said:

What is the difference from the previous run BA? Are you referring to the ecm trop run?

This is the strat thread? 

if it was just one thing from the previous run then I could tell you!  Different placement of anomolies, different placement of high and low heights. From 50 up to 10hpa. Can't see higher than that till the Berlin charts appear. 

 

Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans

Be careful with the Berlin data post day 6/7. I did think the 12z op from yesterday was a bit odd and the latest ec op looks to be back on the same page as previous continuity in the upper strat although I can't see above 10hpa 

Link to comment
Share on other sites

Didn't see the weatheriscool GFS 18z zonal wind speed chart but the 00z maintains it in positive territory with a minimum of 12 m/s at 31/01 00z and 01/02 00z.

Originally the forecasts were looking increasingly like an SSW was probably unlikely, then it suddenly appeared between the 19/01 00z and 20/01 06z before disappearing again at 20/01 12z with the forecast returning similar to previously, so the explanation will be in those runs somewhere.

Interestingly, much of the research seems to suggest that once the NWP picks up on an SSW the modeling tends to be consistent, but that doesn't seem to be the case here with a fair amount of scatter in the GEFS and CFS members throughout the past few days and it may be that the op just flipped to more extreme scenarios and back again just like trop modeling.

edit: Look at the range of ensemble values here in FI, not far short of 30 m/s and above average, to down below -20 m/s!

u10serie_17012100.png

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

Posted
  • Location: Stroud, Gloucestershire
  • Weather Preferences: Extreme!
  • Location: Stroud, Gloucestershire

1hpa winds going negative with a marked drop off from the current zonal flow. No reversal at 10hpa showing yet, we need that sharp drop off high up to filter down.

IMG_1791.GIF

Do we need to see wind reversal at 10hpa for an official SSW or is it dependent on the longitude? 

Temps going up but nothing to impressive at day 10 though all on the way up again at the end

IMG_1792.GIF

Edit

just read your post Blue, and looked at the data from 19th which is showing a more pronounced drop of at 10hpa than the Ines from today that I posted, so should we expect tomorrow's update to reflect this again?

Edited by chris55
Link to comment
Share on other sites

Posted
  • Location: Lytchett Matravers - 301 ft ASL
  • Weather Preferences: Snowy Winters, Torrential Storm Summers
  • Location: Lytchett Matravers - 301 ft ASL

Ian kindly replied to my tweet. 

IMG_5576.PNG

Question for the more experienced members: Because the strat PV hasn't exactly had the easiest of winters, will that help speed up any reversal propagating lower down? 

Mans is that 2 stage dip showing on any Zonal wind predictions that we can see? I can't find charts for zonal wind.

Cheers

Edited by karlos1983
  • Like 5
Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans
1 hour ago, chris55 said:

1hpa winds going negative with a marked drop off from the current zonal flow. No reversal at 10hpa showing yet, we need that sharp drop off high up to filter down.

IMG_1791.GIF

Do we need to see wind reversal at 10hpa for an official SSW or is it dependent on the longitude? 

Temps going up but nothing to impressive at day 10 though all on the way up again at the end

IMG_1792.GIF

Edit

just read your post Blue, and looked at the data from 19th which is showing a more pronounced drop of at 10hpa than the Ines from today that I posted, so should we expect tomorrow's update to reflect this again?

The temps are certainly out on yesterday's run compared to continuity.

Experience teels us that glosea is a very good model for the strat so anything that we get from ian on Twitter should be what we take notice of. I doubt Chris Fawkes is putting those tweets out there without knowing what glosea is seeing 

odds would be on a big warming verifying - whether that is a technical SSW stays unknown at the moment. Whether the upper vortex rebuilds quickly thereafter also unclear.  And looks like a quick response in the trop is unlikely though I expect exeter think there will be downwelling or there isn't much point in Chris Fawkes illustrating that a major warming may be coming. From what ian tweeted it appears mid Feb onwards could be the current expected landing zone for some HLB to appear. 

  • Like 6
Link to comment
Share on other sites

Posted
  • Location: Surrey and SW France.
  • Location: Surrey and SW France.
1 hour ago, Paul_1978 said:

I'm surprised that nobody picked up on his follow up to an earlier SSW tweet.

Just guessing, as he says or are there signs in the longer range products they use.

Late February on the EC46 has suggestion of negative T850 to the south and heights raised over N. Scandinavia.

ec-ens_nat_taem_msl_t850_anom_2017011900

  • Like 4
Link to comment
Share on other sites

Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

Bluearmy's suggestion that "perhaps the sudden influx of high temps into the polar field is playing havoc with the usually consistent modelling" did get me thinking; the state of the tropospheric AO has consequences for the ability of wave activity to deflect/propagate upward into/through the stratosphere, and with all the anomalous heat and moisture getting into the Arctic this winter in association with unusually frequent and deep storms right near the North Pole, I expect it's become a lot more difficult for the models to pin down just what the AO will get up to.

ao.sprd2.gif

One notable side effect is that large positive spikes occur when particularly deep storms move particularly close to the N. Pole. In J. Cohen's blogs I've seen a positive AO linked to a good environment for vertical wave activity flux (WAFz) - but this may actually only be in the sense that a negative AO tends to be associated with downward propagation of anomalies from the stratosphere, with WAFz suppressed.

Interested to hear what others think about this. Cheers :hi:

  • Like 1
Link to comment
Share on other sites

6 hours ago, bluearmy said:

Experience teels us that glosea is a very good model for the strat so anything that we get from ian on Twitter should be what we take notice of. I doubt Chris Fawkes is putting those tweets out there without knowing what glosea is seeing 

odds would be on a big warming verifying - whether that is a technical SSW stays unknown at the moment. Whether the upper vortex rebuilds quickly thereafter also unclear.  And looks like a quick response in the trop is unlikely though I expect exeter think there will be downwelling or there isn't much point in Chris Fawkes illustrating that a major warming may be coming. From what ian tweeted it appears mid Feb onwards could be the current expected landing zone for some HLB to appear. 

I don't think that the Met Office have much which lends a dramatic advantage over the like of GFS/CFS for example with regards to forecasting SSW. As explained in Seasonal winter forecasts and the stratosphere (Scaife et al 2015) they don't claim to have superior deterministic ability than the widely accepted two-week lead time for NWP in general, and for longer periods Glosea5 uses a probabilistic system of hindcasts - rather like a collection of analogues but an order of magnitude larger number of samples - https://ore.exeter.ac.uk/repository/bitstream/handle/10871/20937/Seasonal winter forecasts and the stratosphere.pdf?sequence=1

But as shown in this draft paper Seasonal forecasting of the polar stratosphere and its coupling with the troposphere (Seviour et al - with Scaife again) the Northern hemisphere zonal wind forecast made in November for Dec-Feb has a correlation of only 0.16 with the ERA-Interim reanalysis - https://github.com/wseviour/glosea5-paper/blob/master/paper.md

  • Like 1
Link to comment
Share on other sites

Posted
  • Location: st albans
  • Location: st albans

10Hpa over the pole will go off the scale on Berlin temp graph in the morning. better continuity now on heights also 

ian mentioned two waves likely at 10hpa and GFS now looking like the first wave won't sustain 

 

  • Like 2
Link to comment
Share on other sites

Posted
  • Location: South Croydon
  • Location: South Croydon

"But as shown in this draft paper Seasonal forecasting of the polar stratosphere and its coupling with the troposphere (Seviour et al - with Scaife again) the Northern hemisphere zonal wind forecast made in November for Dec-Feb has a correlation of only 0.16 with the ERA-Interim reanalysis - https://github.com/wseviour/glosea5-paper/blob/master/paper.md"

0.16 wow that's almost random.

Link to comment
Share on other sites

9 hours ago, karlos1983 said:

Ian kindly replied to my tweet. 

IMG_5576.PNG

Question for the more experienced members: Because the strat PV hasn't exactly had the easiest of winters, will that help speed up any reversal propagating lower down? 

Mans is that 2 stage dip showing on any Zonal wind predictions that we can see? I can't find charts for zonal wind.

Cheers

The GFS 12z shows a second dip at the end of the run, but it's speculation not some meteorological secret, it may happen, it might not, there could be three dips, or there might be no SSW at all.

umedel60_17012112ed.png

 

  • Like 3
Link to comment
Share on other sites

Posted
  • Location: Lytchett Matravers - 301 ft ASL
  • Weather Preferences: Snowy Winters, Torrential Storm Summers
  • Location: Lytchett Matravers - 301 ft ASL
1 hour ago, Interitus said:

The GFS 12z shows a second dip at the end of the run, but it's speculation not some meteorological secret, it may happen, it might not, there could be three dips, or there might be no SSW at all.

umedel60_17012112ed.png

 

Thanks, finally a reply. Appreciated!

  • Like 1
Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
  • UK Storm and Severe Convective Forecast

    UK Severe Convective & Storm Forecast - Issued 2024-03-29 07:13:16 Valid: 29/03/2024 0600 - 30/03/2024 0600 THUNDERSTORM WATCH - FRI 29 MARCH 2024 Click here for the full forecast

    Nick F
    Nick F
    Latest weather updates from Netweather

    Difficult travel conditions as the Easter break begins

    Low Nelson is throwing wind and rain at the UK before it impacts mainland Spain at Easter. Wild condtions in the English Channel, and more rain and lightning here on Thursday. Read the full update here

    Netweather forecasts
    Netweather forecasts
    Latest weather updates from Netweather

    UK Storm and Severe Convective Forecast

    UK Severe Convective & Storm Forecast - Issued 2024-03-28 09:16:06 Valid: 28/03/2024 0800 - 29/03/2024 0600 SEVERE THUNDERSTORM WATCH - THURS 28 MARCH 2024 Click here for the full forecast

    Nick F
    Nick F
    Latest weather updates from Netweather
×
×
  • Create New...