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Model Output Discussion - Snow for some, but what else is in store?


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Posted
  • Location: st albans
  • Location: st albans
    3 minutes ago, Kasim Awan said:

    The solar heating wont mean as the front will produce an adiabatic temp. Imo it's the speed of the front which will affect how much evapo cooling will occurr and how quickly the cold layer is mixed.

    could do with a circulation appearing at the triple point although the updated FAX for 6am shows this point to be se Scotland and this then slides south down the front as it  struggles east against the ridge. i'm honestly expecting to see a little west snow at best in the home counties and by the time daylight arrives it may too late for that !

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    Ok, I have a bit of an update. Looks like the correction westward for today got the predicted snowfall about right . Nowcasting really comes into its own for this weekend. The team think another corre

    Please allow me this small divergence mods... I feel like the last 3 weeks have been a bit of a blur. I caught Covid tail end of 2020 and was really rough with it. Low oxygen levels leading to in

    I have had it once in October and again December the 30th. Theres a bit of chat over whether i have had it once had long covid and tested positive again as symptoms came back in December or caugh

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    Posted
  • Location: 50/50 Greece/Germany
  • Weather Preferences: Cold winters, hot summers
  • Location: 50/50 Greece/Germany
    1 minute ago, northwestsnow said:

    Potentially big news!!

    If it moves to 6/7 we should see a swing to blockings soon in EC outputs...

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    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks
    1 minute ago, northwestsnow said:

    Potentially big news!!

    But it is shown as with very little momentum, is it not?

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    Posted
  • Location: Purley, Surrey - 246 Ft ASL
  • Weather Preferences: January 1987 / July 2006
  • Location: Purley, Surrey - 246 Ft ASL
    Just now, johnholmes said:

    But it is shown as with very little momentum, is it not?

    Does it ever have much momentum. The MJO appears to have been in the COD for most of the last few winters with little high amplitude events in any phase.

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    Posted
  • Location: County end Oldham 202 m Above sea level
  • Location: County end Oldham 202 m Above sea level
    1 minute ago, johnholmes said:

    But it is shown as with very little momentum, is it not?

    I'm assuming it's better than phase 3 John ...

    ( And hoping)..

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    Posted
  • Location: North West of Ireland
  • Location: North West of Ireland
    2 hours ago, Catacol said:

    Last post for now - its way out in la la land - but GFS at 9 days is potential snow heaven for some. There seems to be some downbeat feelings in here today so far: I'm not sure why. There is so much going on, and so much potential for winter weather over the next few weeks. Is this not what we come on here for? If it snowed 6ft every year it'd get hellishly boring!

    image.thumb.png.c1849d0501ff6c2b61d5bcd37add96d1.png

     

     

    1 hour ago, Man Without Beard said:

    Right this is a pure speculation post, based on something I've noticed on the GFS parallel in FI:

    image.thumb.png.91ede030752400cc15e0d971b48920df.png

    Notice that little area of surface high pressure poking from Russia back to the North Sea? Back-door cold very nearby? Combined with low pressures running regularly into Southern Britain?

    Will probably come to nothing but I will be looking out to see if this pops up again!

    Please don't take this too seriously as this is purely for enjoyment (the European part of the chart, not the Greenland part!), but...

    image.thumb.png.d24e70a2b4545a5e5d5d85532c59ee6e.png

     

    Are you hinting at a possible easterly flow down the line?

    Edited by Bricriu
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    Posted
  • Location: Berkshire
  • Location: Berkshire
    1 hour ago, tesaro said:

    All this talk of Climate change etc is all very well when trying to diagnose why it was wet rather than White. Climate change or not, there has been some frigidly cold air bottled up in the Northern Hemisphere. What had been missing is the right pattern to deliver  it to our Shores. 

    Yes, I hear you say that it’s Climate Change that is the cause of the said Pattern to be wrong but we are only 2 Years on from the infamous  2018 Beast and 10 years since our 2010 treat. The only discernible difference is the pattern of delivery not the lack of cold available. Some small adjustments here and there and we will be back in the thick of it. 👍

    Most forget The beast appeared TWICE in late Feb, Early March 2018.  I mean to get 2 blasts in one winter?

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    Posted
  • Location: nottingham
  • Weather Preferences: ice days,and snow,snow,snow...
  • Location: nottingham

    For the Greenland high to produce very cold for us, we need a much stronger high, ie yellows and oranges (as seen on meteociel) pushing the lows coming from North America  on a more southerly route, and our trough deeper into the med..

    So far this hasn't really been an option of late on the outputs, greens into Greenland are OK but frought with the danger of west based -NAO and lows coming at us head on and phasing rather than cutting under us, unless we can keep the waa going up into Greenland and cutting off the Atlantic  ,which is difficult to maintain without a strong Greenland high, its always going to be touch and go for cold but chances of heavy snowfall are good for anywhere..

    There is still a chance the GH can produce very cold and keep waa going, as 27% of ECM ensembles at day 10 suggest ,and also the GFS depending on which suite you view say roughly the same but seem higher on the 12z and 18z for some reason..??

    As things stand, its looking good for cold and snow /rain anywhere next week ,maybe even the SE, and 25% chance of very cold, so not too shabby for coldies.

    Going forward ,I would say keep the faith if your a coldie , just had a major SSW and another minor warming which looks to split the already displaced strat vortex, so a reshuffle of the atmosphere looks imminent, and hopefully with a little luck we get high pressure to the N/NE which gives us a much better chance for a memorable cold spell to finish winter...

    I would say 40% change of something severe by the end of winter which is much better than the 5% we normally get.....

    Keep the faith coldies..

     

     

     

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    Posted
  • Location: Broxbourne, Herts
  • Weather Preferences: Snow snow and snow
  • Location: Broxbourne, Herts
    2 hours ago, SLEETY said:

    Historic January would be CET below zero with ice days and wdespread snowcover,but despite the signs and some people thinking that would happen,we have just had transient snowcover mainly  on Northern Hills ,so noting historic at all.

    Need everything shown in the models to move further South for everyone to get into the action,too much atlantic sourced air at the moment,hence only higher ground really effected ,need more N/NE air-flow less sea-track.

    Historically January has been far from a below zero CET month.  What we seem to have been lacking is the odd year, or odd couple of years in a small cluster, that January throws up that's really cold.

    For example, the average for this century 2001 to 2020 is a very mild 4.73C . But the average for the 10 years between from 1967 to 1976 was higher at 4.96C.  The following four years then ran under this average including the spectacular 1979 CET which actually was below zero!

    It could have evolved that this January turned out to be a very chilly one instead of just cold as it will almost certainly still turn out to be. But, to date, its just been a case of that's the way the cookie crumbles!  Maybe it;s a warming climate, maybe it's the relative lack of volcanic activity but I think what's really changed in recent years is the frequency of the spectacular cold Januarys from very occasional to once in a generation,

     

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    Posted
  • Location: Netherlands
  • Location: Netherlands
    2 hours ago, Vikos said:

    Well, you live so close the the "hot" sea, what do you except? M-Europe climate is ALWAYS domintated by ATLANTIC REGIME due the gulf stream. Climate changes do the rest (ice coverage, sea ice cover etc).

    The idea of prolonged ice-cold spells that last over weeks, well, that is history now. I did not have significant winter since years, and I am in the middle of Germany, even farer away from the boiling north sea...

    I expected little of the SSW, because I know that Siberian Warming (wave 1) often puts the stratospheric vortex in the Atlantic Ocean.

    You write about always having an Atlantic Regime, of course we live in a seaclimate. We have a Gulstream. But it ain't true winter we can't get winter over here. As February 2012, 2018 showed. We need easterly winds, than it's not a problem or proper northerly winds. E.g. by a Scandi high or strong Greenlandhigh.

    Edited by sebastiaan1973
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    Posted
  • Location: Netherlands
  • Location: Netherlands
    2 hours ago, tesaro said:

    All this talk of Climate change etc is all very well when trying to diagnose why it was wet rather than White. Climate change or not, there has been some frigidly cold air bottled up in the Northern Hemisphere. What had been missing is the right pattern to deliver  it to our Shores. 

    Yes, I hear you say that it’s Climate Change that is the cause of the said Pattern to be wrong but we are only 2 Years on from the infamous  2018 Beast and 10 years since our 2010 treat. The only discernible difference is the pattern of delivery not the lack of cold available. Some small adjustments here and there and we will be back in the thick of it. 👍

    I wouldn't consider it small adjustments. The realy cold is far away in the north (east).

    GFSAVGEU06_240_2.png

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    Posted
  • Location: Otley(Leeds)
  • Location: Otley(Leeds)

    I hear the word evaporative cooling being banded around an awful lot over the years, now it seems to be mentioned every single snowfall the uk experiences. 

    Am I right in thinking that tomorrow mornings snow event (in places) there will be no evaporative cooling as the wind will be be too strong during the precipitation, mixing out the colder air with parcels of milder air? 

    What we essentially see is rain turning to snow briefly as it hit's the cold air, before the mixing of air parcels aloft quickly turn it to rain and filter down to the lower atmosphere. (obviously the further south east  you go tomorrow the longer it will take to mix out the colder air.) Rather than the rain coming in heavy and over the process of an hour/more turning to snow due to the process of evaporative cooling.

    Edited by Harsh Climate
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    Posted
  • Location: Aberporth S W Wales
  • Location: Aberporth S W Wales
    17 minutes ago, northwestsnow said:

    Icon 144...

    image.thumb.png.e9e15c597b7687e96df01f094a229a2e.png

    No thanks, they can have that one back and try again tomorrow...far too quick with the Atlantic systems, cold hasnt had time to establish itself....rubbish model!

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    Posted
  • Location: Buxton
  • Location: Buxton
    17 minutes ago, Harsh Climate said:

    I hear the word evaporative cooling being banded around an awful lot over the years, now it seems to be mentioned every single snowfall the uk experiences. 

    Am I right in thinking that tomorrow mornings snow event (in places) there will be no evaporative cooling as the wind will be be too strong during the precipitation, mixing out the colder air with parcels of milder air? 

    What we essentially see is rain turning to snow briefly as it hit's the cold air, before the mixing of air parcels aloft quickly turn it to rain and filter down to the lower atmosphere. (obviously the further south east  you go tomorrow the longer it will take to mix out the colder air.) Rather than the rain coming in heavy and over the process of an hour/more turning to snow due to the process of evaporative cooling.

    I'm glad you highlighted this. It is just one of many factors which contribute towards an outcome. Winds at 10-15mph however precip rates over 3mm per hour (heavy) will cancel this somewhat meaning it will be partially effective imo. Other mechanisms such as diabatic cooling will help create a stronger surface profile, i.e. temps which allow for higher accumulations. It's not essential here what is essential is the low adiabatic temp produced by the stagnant cold continental air which isn't mixed further east due to it's depth. The evapo cooling is just helping in a finely tuned way to create a more optimal temp regime.

    Edited by Kasim Awan
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    Posted
  • Location: Home: Chingford, London (NE). Work: London (Central)
  • Location: Home: Chingford, London (NE). Work: London (Central)
    3 hours ago, sebastiaan1973 said:

    With a synoptical heaven you don't need luck 😀

    You always need some luck, particularly when we're talking about an island on the eastern edge of a large ocean. 

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    Posted
  • Location: Cardiff
  • Weather Preferences: Snow sun thunderstorms frost
  • Location: Cardiff

    Any chance February can pack a punch and talk of a nother warming and more pressure on the vortex 

    Edited by Weather roller-coaster
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    Posted
  • Location: South Oxfordshire
  • Location: South Oxfordshire

    What hope in hell the parallel will back this up in a few minutes time? 

    gfsnh-0-114.png

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    Posted
  • Location: Bournemouth
  • Weather Preferences: Dry mild or snow winter. Hot and humid summer.
  • Location: Bournemouth

    T144 Ukmo.  What I would give for the ridge and the artic high to hook up 😩😄 oh well.

    2D193B45-97F0-4B43-B83D-771E10794CB6.gif

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