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Model output discussion 25th Jan - The final third of winter beckons..


Paul

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Posted
  • Location: Pembrokeshire
  • Weather Preferences: Snow
  • Location: Pembrokeshire
    16 minutes ago, johnholmes said:

    Why not simply say what it is?

    It's a phrase to describe a more localised spell of zonality - with full zonal conditions never quite developing.

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    Posted
  • Location: Preston, 19m ASL when tide out :(
  • Location: Preston, 19m ASL when tide out :(
    On 27/01/2017 at 18:52, Seasonality said:

    Maybe western Europe. Still colder further east.

    I'd say +5hpa getting into central Ukraine is about as east in Europe you can get

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

    Just a quick comment regarding the strat and those 10/30 hpa charts that have been posted in the Strat thread that look so impressive regarding a warming.

    here

    strat.JPG

    The warming has been well forecast for at least a week or more now and the (near) SSW (probably now going to be defined as a minor warming rather than a major one, by the met office, because the winds at 60n don't quite reverse) is as we expected.

    Yes a good warming up there, but not such a good result, a displacement of the vortex is the end result from the warming, and unfortunately the displacement does not look favourable if its a high lat block in our area you are after. A split in the strat vortex would be much more interesting, but alas that is not how the strat pattern is responding to the warming. 

    This summary is based on the initial warming and there "might" be some more developments in the strat as we go forward, but the initial warming, that those impressive looking spiking charts at 10/30 that were posted in the strat thread indicated, are actually just showing the expected spike, which as described does not split or displace the vortex into a favourable position for subsequent down-welling.

    If i post some charts for reference,

    You can see that massive warming heading towards the pole,

    ecmwf10f48.gif

    Which is a major departure from what was there before

     

    ecmwf10f24.gif

    But the end result just displaces the vortex from the pole to the lower latitudes and as stated it is displaced southwards over north Europe, so if your looking for a direct correlation between the strat and the troph its not looking ideal!

     

    ecmwf10f120.gif

    We then get the second warming (wave 1, we really need to see a wave 2 injection to split things)

    ecmwf10f168.gif

    Which again results in a slightly displaced vortex, but nothing thats screaming a good troph (troposphere)  pattern if it was to down-well.

     

    ecmwf10f240.gif

    So in summary, even though we get a good strat warming the resulting stratospheric pattern in not looking that good for our region if a direct downwelling is to effect us and result in a colder pattern.

    There is some argument that the displaced vortex may ease the canadian troph PV and perhaps could encourage a colder north west/north flow for us but we shall have to wait and see.

      

     

     

     

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    Posted
  • Location: NR LOURDES SW FRANCE
  • Location: NR LOURDES SW FRANCE

    The ECM has a bit more potential earlier but flatlines later. We really want to see the PV lobe over Canada disconnected from the troughing near the UK and edged nw like the GFS output.

    Overall an unsettled spell of weather coming up with troughing parked over the UK and heavier bands of rain moving in as shortwaves run east into the UK. A chance these could see something wintry on the northern flank depending on what the 850's look like closer to the time.

    Some heavy showers wintry at times in the north so pretty standard winter fare.

     

     

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    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks
    46 minutes ago, Jonathan Evans said:

    It's a phrase to describe a more localised spell of zonality - with full zonal conditions never quite developing.

    I'm old fashioned Jonathan, so to my way=explain what the chart is showing. 'localised...zonality', to me is a meaningless phrase and I would imagine to a lot of new folk trying to get to grips with model outputs quite confusing.

    However each to our own idea.

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    Posted
  • Location: North East Hampshire
  • Location: North East Hampshire
    49 minutes ago, Jonathan Evans said:

    It's a phrase to describe a more localised spell of zonality - with full zonal conditions never quite developing.

    So in other words 'unsettled'.  No need for yet another buzz word to be invented.

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    Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl
    1 hour ago, nick sussex said:

    The ECM has a bit more potential earlier but flatlines later. We really want to see the PV lobe over Canada disconnected from the troughing near the UK and edged nw like the GFS output.

    Overall an unsettled spell of weather coming up with troughing parked over the UK and heavier bands of rain moving in as shortwaves run east into the UK. A chance these could see something wintry on the northern flank depending on what the 850's look like closer to the time.

    Some heavy showers wintry at times in the north so pretty standard winter fare.

     

     

    Yes GFS showing signs of a weakened disconnected PV lobe over Canada as we move out of the first week of Feb, and this would definately encourage an injection of arctic/polar maritime air from a NW/N quarter as being hinted at in its long range output. So all eyes on the strength and position of the lobe over Canada in the coming days, a movement NW is needed to enable colder air to filter our way, and it is very plausible.

    In the meantime, expect sudden short term developments, just as we have now, with a closed low feature crossing the south of the country, but crucially delaying the chance for milder uppers to invade the north, indeed it now looks like it will be Tuesday before the whole of the UK experiences a milder pattern, and in the north, very brief. Lots of snowfall for the scottish ski centres in the coming week which is good news.

     

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    Posted
  • Location: Northwich south cheshire SACRA MEMBER 16/122
  • Weather Preferences: snowy winters,warm summers and Storms
  • Location: Northwich south cheshire SACRA MEMBER 16/122

    That is some temperature contrast tomorrow night on the 18z -9c in NE Scotland 

    +10c in the SE of the UK

    C.S

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    Posted
  • Location: Truro
  • Weather Preferences: winter and summer
  • Location: Truro

    Not a full on Atlantic here, yet another GFS run that suggests possible high pressure to our north and west with a stonking high pressure system setting up to our east could be be seeing signs of change already ...... let's see the low pressure dive deeper south and east.

    IMG_0987.PNG

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    Posted
  • Location: Erith. SE London/kent 40m asl
  • Weather Preferences: Winter Snow, extreme weather, mainly sunny mild summers though.
  • Location: Erith. SE London/kent 40m asl

    Well at least we are seeing improvements on each run from what we had a couple of days ago. 

    gfsnh-0-384.png

    gfsnh-1-384.png

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    Posted
  • Location: Erith. SE London/kent 40m asl
  • Weather Preferences: Winter Snow, extreme weather, mainly sunny mild summers though.
  • Location: Erith. SE London/kent 40m asl

    I know that these charts are right out in FI but if something favourable shows up for a couple of days on the GFS there is a chance that it could be brought forward a bit and other models might come on board. After all this SSW must be having some effect on the PV by the 2nd/3rd week of Feb, anyway we don't need the full split vortex to get some cold our way, just some northern block that sets up in a favourable place.

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    Posted
  • Location: Cyprus and North east Swindon. 104 ASL
  • Location: Cyprus and North east Swindon. 104 ASL

    Well well a Scandy high from the ECM

    IMG_4098.PNG

    Quite a strong Easterly flow around Poland, should be strong enough to hold back the Atlantic...this high starts forming at 192 , still FI though so not so sure!!

     

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

    0Z ECM attempting to develop the near perfect E,ly.

    http://old.wetterzentrale.de/pics/Recm1681.gif

    I say near perfect because the high is descending from the Arctic. Reason I say near perfect is because the lobe of PV doesn't descend with the high i.e Jan 1987. Still if you want a bitterly cold E,ly with very real cold upper temps then the 0Z ECM is the way to go.

    Only downside is I don't believe it after the winter of let downs so far/.

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    Posted
  • Location: Bournemouth
  • Weather Preferences: Dry mild or snow winter. Hot and humid summer.
  • Location: Bournemouth
    1 minute ago, TEITS said:

    0Z ECM attempting to develop the near perfect E,ly.

    http://old.wetterzentrale.de/pics/Recm1681.gif

    I say near perfect because the high is descending from the Arctic. Reason I say near perfect is because the lobe of PV doesn't descend with the high i.e Jan 1987. Still if you want a bitterly cold E,ly with very real cold upper temps then the 0Z ECM is the way to go.

    Only downside is I don't believe it after the winter of let downs so far/.

    I understand your last line but the winter thus far will have no influence on the rest of the winter in terms of if it's a let down or not. Going to be some good fi runs moving forward I feel.

    The ecm t240 is very interesting and if gfs picks this up in future runs but a bit flatter it would still be good imo. 

     

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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)
    11 minutes ago, Ali1977 said:

    Well well a Scandy high from the ECM

    IMG_4098.PNG

    Just need to the Azores ridge to do one, what interests me about the appearance of the Scandi, even if it doesn't bring an easterly initially, is the increase in tropospheric wave number 2 forcing it will bring - which will help towards perhaps splitting the strat PV. Split of the PV much better than displacement for long term prospects of HLB and cold/snow prospects as we head through February.

    Anyway, only one run and we'll see if the EPS z500 mean supports the idea later too.

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    Posted
  • Location: winscombe north somerset
  • Weather Preferences: action weather
  • Location: winscombe north somerset

    So Matthew Hugo predicts half of Feb could be wet windy ,no sign of any cold ,right I, m off out of here ,the guy is very knowledgeable but we will have some very cold air to our far north driving this cyclonic wintry spell and if we get lucky we have a good chance of the white stuff ,right I, m back ,don't give up this cyclonic spell could bring us what we desire ,cheers gang .:yahoo:

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    Posted
  • Location: Marton
  • Location: Marton

    As a general overview we could see the first third of feb the most unsettled and mildest period of the month before the slowdown in zonal winds has an effect on the jet.

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    Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk
    31 minutes ago, Dennis said:

    winter has some time to give a new round in Febr or March

    5.gif

    6.png

    67.gif

    Well said Dennis.

    I need to say this so what if there's no reversal of the stratospheric warming and not to worry about the mjo because since November we had hard frost and some snowfall without a ssw without true high latitude blocking Europe has had a very very cold winter and we were just on the edge of it.

    So my thinking is in the next 5 to 10 days the stratospheric warming combined with mjo and low solar activity we are likely to see a cold spell by mid Feb maybe sooner.

    Minor warming major warming it's still completely better than last winter.

    I expect eye candy in the next 5 to 10 days.

    And them heights in Scandinavia have increased in strength since yesterday as there was signs last night of it strengthening today it's bigger and slightly stronger.

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    Posted
  • Location: st albans
  • Location: st albans
    1 hour ago, Nick F said:

    Just need to the Azores ridge to do one, what interests me about the appearance of the Scandi, even if it doesn't bring an easterly initially, is the increase in tropospheric wave number 2 forcing it will bring - which will help towards perhaps splitting the strat PV. Split of the PV much better than displacement for long term prospects of HLB and cold/snow prospects as we head through February.

    Anyway, only one run and we'll see if the EPS z500 mean supports the idea later too.

    the ec op shows a split devloping in the mid strat by day 10 which I presume has its roots in the wave 2 type set up illustrated 

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    Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

    The early part of Feb is looking pretty wet according to UKMO

    ukm2.2017020300.120.lant.troplant.prp.fcst.gentracker.pngukm2.2017020400.144.lant.troplant.prp.fcst.gentracker.png

    UKMO extended

    ukm2.2017020500.168.lant.troplant.prp.fcst.gentracker.png

    We might see the 1st named storm for over a month if one of those lows comes off

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    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    A lot of negative thoughts re any cold and not sure why.

    The 500mb flow is going to be a very strong westerly over the coming 2 weeks giving some windy spells especially for the Nw'ern half.. Never particularly mild and with contour heights lower at times than the previous many weeks. This allows for colder incursions from time to time, frost in any temporary ridges overnight and wintry type showers in the colder air spells. Something for most weather enthusiasts, even some thunder possible. No prolonged mild spells and sure enough little sign of any prolonged cold. A mix in fact from day to day. In terms of snow then the northern half of the country is better placed but even in some southern areas sleety type showers are quite probable. Lying snow, then yes, only for the higher ground of the northern half with some good falls likely over the Scottish ski areas.

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    Posted
  • Location: Salzburger Sportwelt Lungau/ Pongau Region. Somtimes Skipton UK
  • Weather Preferences: Northeasterly Blizzard and sub zero temperatures.
  • Location: Salzburger Sportwelt Lungau/ Pongau Region. Somtimes Skipton UK
    2 hours ago, Nick F said:

    Just need to the Azores ridge to do one, what interests me about the appearance of the Scandi, even if it doesn't bring an easterly initially, is the increase in tropospheric wave number 2 forcing it will bring - which will help towards perhaps splitting the strat PV. Split of the PV much better than displacement for long term prospects of HLB and cold/snow prospects as we head through February.

    Anyway, only one run and we'll see if the EPS z500 mean supports the idea later too.

    Nick strong backing this morning from our portal forecast for a very cold snowy spell for the middle period of the month with expected A/C airmass taking charge(60%) expectancy. That's a strong forecast rate from our Central European prospective. So we can expect developments in some other model forecasts soon. In the meanwhile this is our 31st day of sub zero temps and locally some valley stations near by could be on for the coldest January for 30 years after a run of exceptionally low night time minimums.However, its been a very dry month for many and a welcome prospect of some snow next weekend in the Austrian Alps butvwill lose the very low temps of the past month but a very cold and snowy mid month beckons. May be its time for the British Isles to get some proper winter charts by mid Feb?

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    Posted
  • Location: Peterborough N.Cambridgeshire
  • Location: Peterborough N.Cambridgeshire
    2 hours ago, That ECM said:

    I understand your last line but the winter thus far will have no influence on the rest of the winter in terms of if it's a let down or not. Going to be some good fi runs moving forward I feel.

    The ecm t240 is very interesting and if gfs picks this up in future runs but a bit flatter it would still be good imo. 

     

    Reason why im not paying too much attention to the 0Z ECM at the moment is because of the lack of support from the other models. The key difference with the ECM is from +144 onwards when the high descends from the Arctic.

    Also I noticed someone mentioned a Scandi HP. There is a massive difference between an E,ly that develops from a developing high pressure over Scandi, than a high pressure that descends S from the Arctic into Scandinavia. The latter tends to be much colder as it pulls much colder uppers from the Arctic.

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