Jump to content
Cold?
Local
Radar
Snow?

Model output discussion 25th Jan onwards


Recommended Posts

Posted
  • Location: Peterborough N.Cambridgeshire
  • Location: Peterborough N.Cambridgeshire

    The main reason I raised the topic was that I could not see where the trough disruption quoted by several posters this morning was occurring?

    Does anyone else see trough disruption in the GFS output?

    Please show me as I am honestly unable to see just where this is happening-that is all I am asking.

     

    and to answer mucka, it is the loose and at times incorrect use of some terms that is misleading. Why use the term if others are not sure what you are saying?

    Personally I cannot see trough disruption in the GFS output like you John.

     

    Trough disruption to me is when the jet stream buckles and the bottom of the trough becomes disconnected and cut off.

     

    Back to the models and last time I posted a few days ago I referred to the Iceland SLP mean. As we can see below the mean is clearly rising.

     

    http://cdn.nwstatic.co.uk/ensimages/ens.20140204/00/prmslReyjavic.png

     

    So no obvious cold spell on the horizon but signs one could develop in the model output over the next few days and this could even occur at +192 to +240 rather than +384!

    • Like 3
    Link to post
    Share on other sites
    Spotted a post you think may be an issue? Please help the team by reporting it.
    • Replies 2.4k
    • Created
    • Last Reply

    Top Posters In This Topic

    Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth

    Models this morning continue to show considerable rain and wind especially in the south and west, but longer tern changes are emerging. Both op and mean runs indicate the decline of the East Canadian Vortex next week, flying in the face of some who have suggested it was locked in for the month - as I mentioned a week ago, it is rare to get patterns locked in for that long over the UK, perhaps aside a Bartlett High scenario in late autumn.

    Many models (see NOAA 8-14 day anomaly chart, for instance) suggest the vortex will weaken and partly relocate near Alaska and partly head towards the UK. Consequences for the UK - still unsettled but the source of air might start to vary a little. In the 7-14 day period, there may be opportunities for colder air to the north to drift down over northern parts and I see opportunities for brief north-westerlies, so although no freeze-up, snow cannot be discounted. Ridging from Azores not favoured for now, so unlikely to be that much drier, but not mild either. Longer term, I think it's more up for grabs - the NOAA chart I mentioned hints that a Greenland high might be able to form, and the ECM shows heights building back from the east. We're talking the third week of February here, so still not impossible we'll get proper cold.

    • Like 7
    Link to post
    Share on other sites
    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    Many models (see NOAA 8-14 day anomaly chart, for instance) suggest the vortex will weaken and partly relocate near Alaska and partly head towards the UK. Consequences for the UK - still unsettled but the source of air might start to vary a little. In the 7-14 day period, there may be opportunities for colder air to the north to drift down over northern parts and I see opportunities for brief north-westerlies, so although no freeze-up, snow cannot be discounted. Ridging from Azores not favoured for now, so unlikely to be that much drier, but not mild either. Longer term, I think it's more up for grabs - the NOAA chart I mentioned hints that a Greenland high might be able to form, and the ECM shows heights building back from the east. We're talking the third week of February here, so still not impossible we'll get proper cold.

     

    Yes I would agree with those ideas but prefer myself to wait for 3-4 days to see how both the 6-10 and 8-14 versions continue with those suggestions.

    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: Wellseborne, Warwickshire
  • Weather Preferences: Southerly tracking low pressure in winter. Hot and thundery in the summer
  • Location: Wellseborne, Warwickshire

    Models this morning continue to show considerable rain and wind especially in the south and west, but longer tern changes are emerging. Both op and mean runs indicate the decline of the East Canadian Vortex next week, flying in the face of some who have suggested it was locked in for the month - as I mentioned a week ago, it is rare to get patterns locked in for that long over the UK, perhaps aside a Bartlett High scenario in late autumn.Many models (see NOAA 8-14 day anomaly chart, for instance) suggest the vortex will weaken and partly relocate near Alaska and partly head towards the UK. Consequences for the UK - still unsettled but the source of air might start to vary a little. In the 7-14 day period, there may be opportunities for colder air to the north to drift down over northern parts and I see opportunities for brief north-westerlies, so although no freeze-up, snow cannot be discounted. Ridging from Azores not favoured for now, so unlikely to be that much drier, but not mild either. Longer term, I think it's more up for grabs - the NOAA chart I mentioned hints that a Greenland high might be able to form, and the ECM shows heights building back from the east. We're talking the third week of February here, so still not impossible we'll get proper cold.

    A really well written post rjbw . Things are showing up for a change next week with some colder air mixed in so maybe some snow for some. And re deep cold in late feb we all know is easily accessible in fact much more likely than in december. I think most importantly we need Europe to go into the freezer by mid feb. Yes northerly winds are good. But if we can have a freezing continent we will always have a chance of tapping into cold. Very cold air bottled in the Arctic flooding unto europe will bring exceptionally cold air a long way south well into march as we saw last year . Remember the isle of white having 40cm last march ? Not to mention the snow storm on the 22nd in many places. Anywhere that had uppers below 0c were having heavy snow . I was on the border line so I had snow to rain as it first went north then back to snow as it sank south during the friday night . so still plenty of time yet. But first thing first wait for this horribly tough vortex to weaken and move northwest some what before we can look out for real cold air . Edited by Severe Siberian icy blast
    • Like 3
    Link to post
    Share on other sites
    Posted
  • Location: st albans
  • Location: st albans

    re jh - i am using the term re 'cyclonic trough disruption'  as per todays fi ecm run as the lower portion of the trough heads into se europe

     

    i am looking ahead and wondering what the record is for average slp across the uk through DJF ..............  are there any stats on this (kevin) ??  surely this winter must be approaching a low average record return?

    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: Preston, 19m ASL when tide out :(
  • Location: Preston, 19m ASL when tide out :(

    Would have a thought a few of these charts from the 06z ensembles stamps would be bringing us some colder air from the North, certainly some interest from week 2 for changes to happen, maybe earlier. the ensemble graphs aren't painting a true picture showing a continuation of zonal and wet.  For now yes, but the domination looks like it may be starting to break up, like we would expect as we go through February

    post-4955-0-95348200-1391518411_thumb.pn

    post-4955-0-72023500-1391518423_thumb.gi

    Edited by Nicholas B
    Link to post
    Share on other sites
    Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

    good job I researched, because to me, trough disruption is what happens at tea time on the pig farm...

     

    Posted Imageimages.jpg Posted Image

     

    And aren't the model outputs making a right sow's ear of things at the moment for us coldies.  Posted Image

     

    Nonetheless, there should be a bit of everything for everyone aside from those looking for prolonged cold. Time is ticking by but things could well change in future, just right now any NH changes aren't likely to influence our shores until at least the 10th or 11th February at the earliest. Before then, some deluges, strong winds, more Thunder & Lightning for a few (as per today in places), hill snow and flying fish due to potential development of waterspouts in prone areas. Anything else I've missed? Posted Image

    Edited by gottolovethisweather
    Link to post
    Share on other sites
    Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

     

     

    good job I researched, because to me, trough disruption is what happens at tea time on the pig farm...

     

    Posted Imageimages.jpg Posted Image

    And if we get snow next week the price of bacon will go upPosted Image

    Edited by Frosty.
    • Like 2
    Link to post
    Share on other sites
    Posted
  • Location: NR LOURDES SW FRANCE
  • Location: NR LOURDES SW FRANCE

    Just looking at the latest strat forecasts and these aren't too bad,and in conjunction with the movement of the PV over Canada further to the nw then this does leave room for some more favourable synoptics to develop in western Europe.

     

    I think the issue however is where any decent cold pool could set up, what we don't want to see is for high pressure to the east to make another halfhearted attempt to move west because this could trap troughing over the UK so even with an improved picture over the ne USA essentially you're left in a stalemate. Unless you get blocking over the top of any troughing then that would be  another load of frustration!

     

    The NWP generally seems to be edging the jet southwards and this would be supported by the strat and the reversal of zonal winds up there, this reversal weakens later but generally theres very little oomph left to the north so some weakish pressure rises over the Arctic look likely, this against the supercharged jet allied with the limpet Canadian PV of recent weeks would probably not amount to much but if we do indeed see that PV weakening and edging further to the nw then the balance is a bit more in favour of at least some trough disruption near the UK with some more energy heading se into Europe.

     

    But its where any real cold could come from that's still unresolved, I think the models are still adjusting to what could happen on that front and this southwards jet adjustment is still in its early stages.

     

    So a few chinks of light for coldies today but there are still no guarantees that we'll end up with where most in here would like and that's a decent cold spell with snow.

    • Like 5
    Link to post
    Share on other sites
    Posted
  • Location: Exile from Argyll
  • Location: Exile from Argyll

    re jh - i am using the term re 'cyclonic trough disruption'  as per todays fi ecm run as the lower portion of the trough heads into se europe

     

    i am looking ahead and wondering what the record is for average slp across the uk through DJF ..............  are there any stats on this (kevin) ??  surely this winter must be approaching a low average record return?

     

    I don't know about the records for winter as a whole but the slp anomaly so far this winter is pretty shocking.

     

    Posted Image

    ......and when the anticyclonic start to Dec '13 is removed......

     

    Posted Image

    Link to post
    Share on other sites
    Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

    For those that may not have seen it, there is a dedicated storms thread and this latest posting informs us just how serious the forthcoming spell could become for some. Posted Image

     

    http://forum.netweather.tv/topic/79252-atlantic-storms-february-2014/?p=2917230

    Edited by gottolovethisweather
    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: IN THE FOOT HILLS AND DENSELY FORESTED AREAS OF TUNBRIDGE WELLS IN KENT
  • Weather Preferences: I like a bit of weather
  • Location: IN THE FOOT HILLS AND DENSELY FORESTED AREAS OF TUNBRIDGE WELLS IN KENT

    For those that may not have seen it, there is a dedicated storms thread and this latest posting informs us just how serious the forthcoming spell could become for some. Posted Image

     

    http://forum.netweather.tv/topic/79252-atlantic-storms-february-2014/?p=2917230

    Thanks for that... Going down to check our ewes in a while. Praying to God that the one we had on the 30th January was an early bird due to the fact of Dave the Ram starting the party early. Sunny and dry in Tunbridge Wells as I write.
    • Like 3
    Link to post
    Share on other sites
    Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

    I would also be interested in someone clarifying this! The term (among many in here) has had me scratching my head for a while.

    Ditto, Nick...When the Yanks are looking for an UNSUB (in model terms: snow) they often send out an APB???Posted Image

    Link to post
    Share on other sites
    Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

    Personally I cannot see trough disruption in the GFS output like you John.

     

    Trough disruption to me is when the jet stream buckles and the bottom of the trough becomes disconnected and cut off.

     

    Back to the models and last time I posted a few days ago I referred to the Iceland SLP mean. As we can see below the mean is clearly rising.

     

    http://cdn.nwstatic.co.uk/ensimages/ens.20140204/00/prmslReyjavic.png

     

    So no obvious cold spell on the horizon but signs one could develop in the model output over the next few days and this could even occur at +192 to +240 rather than +384!

    So, why can't folks just say that then Dave?Posted Image 

    • Like 1
    Link to post
    Share on other sites
    Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl
    Posted (edited) · Hidden by winterof79, February 4, 2014 - not a correct way to respond
    Hidden by winterof79, February 4, 2014 - not a correct way to respond

    Yes it is used rather liberally and quite loosely no doubt, as with much of the terminology used in here but I'm not sure I would have to preface trough disruption with cyclonic in the above example for people to understand what I was talking about. (The forum is not just for those with an academic meteorological background and caters for all levels - where people are wrongly using a term or misinterpreting a chart they usually get a gentle nudge in the right direction from other members which keeps the forum  popular and friendly, people shouldn't be afraid to post),

    If I am using it incorrectly or people don't understand what I'm referring to I would personally be quite happy to change my ways.

    I have been offline most of the day.

    I used the term to show areas/troughs  of low pressure disrupting/filling over the UK in situ rather than blasting through .Maybe i was incorrect.I also think quite a few others knew what i was alluding to.Always willing to learn.

     

    Obviously the better informed on here have been wound up by the term.Why did you not just kindly state that we had used the term incorrectly if you saw no "Trough disruption" or as Muka says give us a nudge instead of trawling out all the technical terms.Posted Image

    Edited by winterof79
    Link to post
    Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl

    The theme of lows filling in situ over the UK looks set to continue

    http://modeles.meteociel.fr/modeles/gfs/runs/2014020412/gfs-0-132.png?12

     

    Colder air mixing in too.

    Link to post
    Share on other sites
    Posted
  • Location: Cyprus and North east Swindon. 104 ASL
  • Location: Cyprus and North east Swindon. 104 ASL

    The models do seem to look better mid term, cutting off the raging PV. It's hard to think we are in for wintery conditions though, the EC32 has been fairly consistent this year, as have mogreps. The METO are saying nothing cold forecast for the foreseeable...I hope they are wrong!!!

    Link to post
    Share on other sites
    Posted
  • Location: East Anglia
  • Location: East Anglia

    Something is afoot, we are starting to see a lot of variability from the mid range onwards and signs that the PV is running out of steam and shifting, I expect to see some interesting charts over the coming days.

    • Like 4
    Link to post
    Share on other sites
    Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

    Northern blocking starting to develop on the 12z if this continues we could be looking at a colder second half of the month

     

    Posted ImagePosted ImagePosted ImagePosted ImagePosted Image

    • Like 7
    Link to post
    Share on other sites
    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    Northern blocking starting to develop on the 12z if this continues we could be looking at a colder second half of the month

     

     

     

    However, caution, as it is one run and not much like the 06z output at a similar time range.

    As always at this range, checking each frame on each run is usually a waste of time in terms of verifying. Much more sensible to check with the previous 12z run and before to see if some kind of continuity is developing.

    • Like 4
    Link to post
    Share on other sites
    Posted
  • Location: Nuneaton,Warks. 128m asl
  • Weather Preferences: Snow then clear and frosty.
  • Location: Nuneaton,Warks. 128m asl

    Certainly not a common sight to see the depth of cold from the west across the Atlantic

    http://www.meteociel.fr/ukmo/runs/2014020412/UW72-7.GIF?04-17

     

    steep lapse rates behind the cold fronts would give plenty of snow showers at elevations especially Highlands,Pennines and possibly Welsh mountains etc.

    • Like 6
    Link to post
    Share on other sites
    Posted
  • Location: West Sussex
  • Weather Preferences: Extreme cold & snow
  • Location: West Sussex

    Right at the end of FI, there's Nick's cold air source that he was worrying about earlier

    Posted Image

    Posted Image

    Synoptically nice as well BUT .. FI of ocurse.

    Edited by Purga
    Link to post
    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

    Well a less stormy cooler gfs run. Thats all you can say at the moment. Whether it's a trend or a hiccup time will tell.

    Link to post
    Share on other sites
    Guest
    This topic is now closed to further replies.
    ×
    ×
    • Create New...