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


Paul

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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)

    @Argyle1980 certainly the jet is tracking further south across the Atlantic into SW Europe next week and beyond, but it turns north over or to east of UK, which is not very conducive to any ridge to our N or NE having any influence at keeping the Atlantic lows at bay, as the ridges look to be surface based. Also, there is no SSW at the moment, perhaps close to one end of the month, but may not come off and certainly we are way off the warming working down to the troposphere. So don't think we'll see any drastic changes until sometime in Feb.

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

    PV not looking quite as strong/formed in FI. At some point over the next few day we "might" start seeing some better FI charts as possible strat warming starts effecting the NH, whilst FI charts aren't to be trusted it will be nice if we see a general mix of ENS will a little PV disturbace going on.  There is also a fair amount of WAA being injected on the Pacific side so it would't take a huge change around Greenland to have some weak split and some blocking occur towards the second week of Feb.

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

    @Nick F thank you for your response. I agree with you re SSW but in my mind was thinking if we see such an event come the beginning of the month we could then see greater hights opened up to our north, provided it does work in our favour .

    thats where I'm looking right now and with the jet stream trying to dig further south it's a far better direction than full on Atlantic attack.

    also keeps things more interesting.

    happy trend searching!

     

     

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

    I think for the time being its best to lower expectations for the next few weeks. Even though the jet is tracking further south we're not seeing any outputs really wanting to drive those low heights into Europe and develop much ridging to the n/ne.

    Having said this for the far north it maybe possible to see some snow as some colder air heading south could occasionally engage low pressure.

    The issue is really upstream because we're not seeing much amplification to help drive low pressure further se once it gets near the UK and the PV lobe over Canada is a sticking point because that just flattens the pattern out, there is still a low probability that the reduction in strat zonal  winds could feed into a bit more amplification over the USA and Canada.

    But best at this stage to not expect much and if something pops up then great.

    If we're looking for something to keep interest going then I think its going to be MJO led, for much of the winter we've seen a lot of destructive interference which has modified its impact on the NH pattern.

    Although I posted this a few days back this NCEP update is now looking even more important:

    "Therefore, the MJO is anticipated to remain active over the next two weeks, with the convective response becoming more consistent with historical composites during Week-2 as destructive interference with the other modes lessens."

    I wouldn't give up hopes yet of seeing a decent wintry spell including snow and not just frost. I wouldn't worry about increasing solar energy, thinking of the reverse given you can get 30+ in August you can still get ice days even later in February and if I can get those this far south in late Feb , early March then certainly the UK can. If you get the right synoptics even late Feb can deliver.

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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)
    5 minutes ago, Argyle1980 said:

    @Nick F thank you for your response. I agree with you re SSW but in my mind was thinking if we see such an event come the beginning of the month we could then see greater hights opened up to our north, provided it does work in our favour .

    thats where I'm looking right now and with the jet stream trying to dig further south it's a far better direction than full on Atlantic attack.

    also keeps things more interesting.

    happy trend searching!

     

     

    IMO, the downwelling of the strat warming/zonal reversal will be a slow process based on current zonal wind forecasts, so don't expect a quick response in the troposphere if the downwelling occurs. I would be looking at the MJO wave propagation to bring a change to the upper flow pattern that may favour blocking in the meantime, could be in a more favourable phase (7/8) for blocking by 2nd week of Feb.

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    Posted
  • Location: Poole, BH14
  • Location: Poole, BH14
    48 minutes ago, Argyle1980 said:

    Still wondering weather we could see pressure rise more to our north/east.

    with the low pressure system diving south and east all the time along with the jet stream I think this could be where we start to see somthing develop.

    again I don't think anything is set in stone right now and with SSW going on i really don't think we can rule anything out.

    change is a foot!  One way or another .

    IMG_0968.PNG

    IMG_0969.PNG

    Totally agree with this comment the jet is not going to rage directly over the top of the UK but instead run south east. Pretty sure this will only help the block push back west with a chance of hight rises to our north east. Those predicting a warm wet February are jumping the gun way to soon. I give it a week of more unsettled weather and it's certainly not going to last for all of February this is by no means a done deal yet.

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    Posted
  • Location: Tyrone
  • Location: Tyrone

    Pressure rise pushing east towards Iceland and Greenland is one to watch for sure jet is riding far enough south to allow the height rises. Lows cutting under digging further South through time.

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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)

    500mb cold pool moving north out of France this evening/tonight forecast to bring a wintry mix of precipitation, so some in E England could wake up to a dusting on Friday morning, before turning milder during the day as wind veers southerly

    gfsgif_500.gifgfsgif_ppn.gif

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    Posted
  • Location: West Sussex
  • Weather Preferences: Extreme cold & snow
  • Location: West Sussex

    Not a bad sasauge to cheer everyone up

    GFSP19EU06_384_1.png

    GFSP19EU06_384_2.png

    Although rank outsiders it has to be said, at least there are some cold runs starting to emerge again in the GEFS 06z a bit more in the nearer time frame this one

    GFSP04EU06_132_1.png

    Block possibly a tiny bit more resilient?

     

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    Posted
  • Location: st albans
  • Location: st albans

    As I have posted previously, the likelihood of snowfall is inversely proportional to posts showing cold individual ensemble members in this thread !

     

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    Posted
  • Location: South Essex
  • Location: South Essex
    1 hour ago, Nouska said:

    A Bartlett, you say .... "not exactly the same as 1988 version" ..... damned right - nothing at all like the '88 orange monster.

    I've never seen a 'blue Bartlett' before ... maybe it's been affected by all the European cold. :cold:

    What you are seeing is mostly returning polar maritime air - a Bartlett has very warm upper air, centred over France, and feeds a constant train of tropical maritime air into the UK.

    Compare the 18Z animation to a typical Bartlett type chart.

    tempresult_fww2.gif    archives-1998-2-12-0-0.png

    At the risk of being picky, that's not the 18Z run that I had referred to :oops:. FWIW I'd agree with you based on the 00Z run that you have used, nor did I even say it would happen.

    Additionally, there is NO definition in meteorology of what constitutes a Bartlett so I can't really be wrong can I? For me, its the persistence of the pattern not the individual chart.  I can and do accept that others have different views though so as I said last night lets just agree to disagree otherwise its just point scoring.  

    Edit: I'm looking forward to the upcoming 'sausage' analysis now Purga has quoted that :rofl:

     

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

    Regarding tomorrow Arpege also show some rain and snow getting into the se. Nothing heavy but might give a dusting before less cold conditions move in. The Euro 4 less interested and just brings in some rain.

    Tomorrows UKMO fax chart for 0600hrs shows a trough close to the se:

    fax24s.gif

     

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    Posted
  • Location: Tyrone
  • Location: Tyrone

    Every GFS run everything seems to get pushed ever so slightly west if this keeps happening then you never know might allow heights to rise even more to the north to get the undercut that we need around day 5.

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    Posted
  • Location: Warsaw, Poland. Formerly London.
  • Weather Preferences: Four true seasons. Hot summers and cold winters.
  • Location: Warsaw, Poland. Formerly London.
    4 minutes ago, booferking said:

    Every GFS run everything seems to get pushed ever so slightly west if this keeps happening then you never know might allow heights to rise even more to the north to get the undercut that we need around day 5.

    Yes, there has been a trend to edge west. Has been noted in the mid term as well as short term, be interesting to see how it progresses over next couple of runs.

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    Posted
  • Location: Royston, Herts 76m asl
  • Location: Royston, Herts 76m asl
    3 hours ago, Nick F said:

    500mb cold pool moving north out of France this evening/tonight forecast to bring a wintry mix of precipitation, so some in E England could wake up to a dusting on Friday morning, before turning milder during the day as wind veers southerly

    gfsgif_500.gifgfsgif_ppn.gif

    Hi Nick

    I'd be really interested in your opinion on this.  Taking my location as an example, the GFS is showing a max of 6C tomorrow and the Met is saying much the same.  This seems to me to be a huge uptick compared to, er, -1C or so today.  I know that we can get rapid uplifts of temperature, but I'd expect that kind of lift to be associated with an Atlantic front introducing much milder air.  That is not happening (as yet).  The change tomorrow is a subtle shift in wind direction to emanating from more central France rather than central Europe.  My conclusion: it will be milder tomorrow but not as much as the models are saying.

    Do you agree, or is there something I am missing as to the reason why there will be such a significant change in surface temp between today and tomorrow?

    Thanks in advance, WB

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    21 hours ago, Nick F said:

    500mb cold pool moving north out of France this evening/tonight forecast to bring a wintry mix of precipitation, so some in E England could wake up to a dusting on Friday morning, before turning milder during the day as wind veers southerly

    gfsgif_500.gifgfsgif_ppn.gif

    A CHANCE OF A LITTLE SNOW IN THE SOUTH-EAST ON FRIDAY MORNING?    HERE IS SOMETHING TO LOOK FOR IN THE 12Z OUTPUT THIS AFTERNOON AND THIS EVENING

    ***CLOSING UPDATE AND AN APOLOGY 0645 FRIDAY*** Although the timing of the arrival of the cold pool was accurate, some of the precipitation has fizzled out and the track is marginally further eastwards. The NetWeather radar at 0615 radar showed that there was a mix of rain, freezing rain, sleet, wet snow or snow and rain (mostly over the North Downs) and only "briefly" a very small area of snow in the Folkestone area. Surface temperatures have risen slightly but are mostly close to freezing. As this tracks north-north-westwards over East Anglia and up the east coast of England this morning, it looks like freezing rain and ice may be more of an issue. I apologise to those who I might have raised their hopes. I was trying to create a little interest on this thread that had become very quiet with a sombre mood setting in.   

    Please read this post in conjunction with my long post on page 1 of this thread which contains comprehensive coverage of the current situation with many charts including some live ones. This is to allow those of you who are interested in following the very exciting forthcoming short term changes. I have added various updates to that post, so I will not repeat them here.     ***UPDATED WITH 2000 DATA (SEE BELOW) - SOME SNOW SEEMS MORE LIKELY***

    Gosh it's so quiet on here again today. Most of you guys spend all winter chasing cold patterns that might deliver some snow but you seem to miss out on so many other exciting weather events. We had the brief Arctic cold snap that started exactly 3 weeks ago with some snow in many parts of the country. Since then, the cold never really left the extreme south-east and has spread back to most southern parts for much of the last fortnight. Although it has been considerably milder further north, the south is heading for a colder than average January. I have been banging on about the strength and persistence of the Euro cold block for 3 weeks now.  I did several posts on various aspects of this, such as the huge diurnal ranges and the extremely low dew points. During the last 24 hours we have seen the winds strengthen from the south-east bringing in some exceptionally cold air off the near continent. Many parts of the south-east have had an ice day. Although it now seems highly likely that the milder air will push in from the west during the next few days, there is a really fascinating battle ground developing (caution: not blizzard conditions) with the chance of a little snow in the south-east early tomorrow morning.

    I noticed the upper cold pool that @Nick F  and @nick sussex refer to above. Nick's charts show part of this. Let's have a slightly deeper look. 

    gfs-13-18.png?6  gfs-3-24.png?6  gfs-1-24.png?6 ECM1-24.GIF?26-12 gens-0-0-24.png  

                                                                       DEW POINTS 1648 THURJjAN 26TH             DEW POINTS "LIVE" CHART          CURRENT SURFACE TEMPS "LIVE"   SURFACE TEMPS 1648 THUR JAN 26TH

    20170126.1030.PPVE89.png   pointrosee-16.png   pointrosee.png  temp.png    temp-16.png

    NOTE: The 1648 chart shows most of Europe close to their max temps for today (Thursday) - so follow the live chart as temps are already dropping again

    The GFS 6z and the ECM 12z both show the cold pool moving north out of France overnight and across south-east England early on Friday morning. The timings vary but it looks to be between 0700 and 1300 on Friday. Now, even if the milder air has moved into the west by then, the east is still likely to have temps close to freezing point. Remember you do not need 850s around or below -8 or dams below 528 when we have a continental surface flow. The dew points are low enough, so that most of "any" precipitation could easily fall as snow. Any modestly enhanced developments could give a rather more general snowfall - probably only a slight covering at best. So, look out for the developments in the 12z output and especially when the latest MetO fax chart comes out for 0600 Friday (due shortly). I have posted the 0z one which Nick Sussex posted with that tell tail trough moving up over the south-east. I shall be out now until about 2000 but I may well add to this most again after that. I hope, in the meantime that several of you have posted on this fascinating bit of "nowcasting".

    I also feel that there may still be a little life yet in the Euro cold block - perhaps a "dead cat bounce". The milder air might push across us but there could still be several colder pulses during the transition over the next few days. 

    UPDATE (Thur 2000):   These charts are either live or automatically update every few minutes - so that you can follow the changes

    Live France and S England Precipitation             Live NW Europe Satellite                  Live NW Europe surface winds             Live All Europe Pressure Chart                 Live France and South UK Chart  

    lastsnowradar.gif   anim_ir.gif  vent.png  pression2_eur2.png     pression2.png

    12z Output:

                 Met O Current 1800 Thur                             Met O Current 1200 Fri                      GFS 12z T+18  0700 Fri                          ECM 12z T+0 1300 Thur                          ECM 12z T+24 1300 Fri

     20170126.1908.PPVA89.png   20170126.1621.PPVE89.png  gfs-0-18.png?12 ECM1-0.GIF?26-0  ECM1-24.GIF?26-0

    All the 12z models now show the upper cold pool. it is moving up through southern and into central France right now (2000 Thur) and the area of precipitation is moving steadily north-north-westwards and more or less on course for London and south-east England around 0700 on Friday. It's mostly quite light but in the last couple of hours one or two heavier echos have shown up. As it moves into the colder air further north it should readily turn to snow (and some of it already has (pink on the radar chart). It might fizzle out of it might become heavier and more extensive. The upper cold pool reaches north-east England around 1300 Friday. The trough shown on the Thursday 1800 MetO fax chart over south France is the same trough that is shown on the Friday 1200 chart over Eastern Scotland and the North Sea - both are associated with the same cold pool.

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    Posted
  • Location: Netherlands close to the coast
  • Location: Netherlands close to the coast

    The normally flat-as-a-pancake GEM almost creates a scandi high starting at 120h, interesting to see what ECWMF will do

     

    gemnh-0-150.png?12

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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)
    48 minutes ago, Weather Boy said:

    Hi Nick

    I'd be really interested in your opinion on this.  Taking my location as an example, the GFS is showing a max of 6C tomorrow and the Met is saying much the same.  This seems to me to be a huge uptick compared to, er, -1C or so today.  I know that we can get rapid uplifts of temperature, but I'd expect that kind of lift to be associated with an Atlantic front introducing much milder air.  That is not happening (as yet).  The change tomorrow is a subtle shift in wind direction to emanating from more central France rather than central Europe.  My conclusion: it will be milder tomorrow but not as much as the models are saying.

    Do you agree, or is there something I am missing as to the reason why there will be such a significant change in surface temp between today and tomorrow?

    Thanks in advance, WB

    Could be right that it won't turn out as mild as forecast by GFS/MetO, afterall, they were predicting 5C for today in London a few days ago, then 3C today, but it has barely got above freezing. Having said that, as the wind veers southerly tomorrow, the source area of the wind coming up is southern France / northern Spain - though I question how quickly this milder air will get here.

    Anyway, an ice day for many in England today, not often we get those, certainly not since 2010 anyway. Some wintry showers for some in the east tonight could give a dusting too. But maybe this more to talk about in the regionals!

     

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    Posted
  • Location: Heckmondwike, West Yorkshire
  • Location: Heckmondwike, West Yorkshire
    3 minutes ago, ArHu3 said:

    The normally flat-as-a-pancake GEM almost creates a scandi high starting at 120h, interesting to see what ECWMF will do

     

    gemnh-0-150.png?12

    Just about to post that we are due an ecm special tonight :)

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

    This looks a decent chart, massive ridge of WAA getting quite high towards the pole on the Pacific/Alaskan side, and weakened PV around Greenland and NE Canada, and Jet well South too. A blast of WAA near Labrador from here and you'd get the split allowing all the cold air in Siberia to head SW. 

    Prob won't come to much but it's not a full on Zonal fest.

    Edit - and as expected didn't happen, and with nothing on the METO long range suggesting anything blocked or cold I doubt it will. 

    IMG_4077.PNG

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    Posted
  • Location: Whitefield, Manchester @ 100m
  • Location: Whitefield, Manchester @ 100m
    11 minutes ago, Nick F said:

    Could be right that it won't turn out as mild as forecast by GFS/MetO, afterall, they were predicting 5C for today in London a few days ago, then 3C today, but it has barely got above freezing. Having said that, as the wind veers southerly tomorrow, the source area of the wind coming up is southern France / northern Spain - though I question how quickly this milder air will get here.

    Anyway, an ice day for many in England today, not often we get those, certainly not since 2010 anyway. Some wintry showers for some in the east tonight could give a dusting too. But maybe this more to talk about in the regionals!

     

    This is a good point. I don't remember a high of -2C in South East (which we've seen in Southend) being forecast for today at the beginning of the week!

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

    Still a chance of a cold end to Winter, hard to forecast at this stage though I'm sure -  lets hope we get some luck.

    IMG_4079.PNG

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