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Model Output Discussion - The Run In To Christmas


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

    The UKMO is ghastly for cold and the reason is the lack of a developed shortwave which is expected to engage the PV over in the USA .

     

    If you don't get that interaction upstream then the chances for cold diminish significantly for the UK. If the UKMO is wrong with the upstream shortwave then its output can be disregarded completely. If its right then cold prospects I'm afraid are likely over.

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    Unfortunately, there needs to be a recognition that if we share at *this tentative juncture* the exact nature of what we have as Ops Centre guidance, certain individuals will inevitably extrapolate/wa

    If the UK can't get cold from an upstream pattern with a negatively tilted troughing setting up over the ne USA , indeed the best set up since two winters ago then I will seriously consider throwing m

    The good news just keeps on coming!   Upstream pattern is falling into place to deliver what many people in this thread want to see, NCEP give us the best update since winter 2012/2013,  indeed I'm

    Posted Images

    Posted
  • Location: Beverley, E Yorks, 19m ASL
  • Weather Preferences: Snow, Thunder - not necessarily at the same time!
  • Location: Beverley, E Yorks, 19m ASL

    The UKMO is ghastly for cold and the reason is the lack of a developed shortwave which is expected to engage the PV over in the USA .

     

    If you don't get that interaction upstream then the chances for cold diminish significantly for the UK. If the UKMO is wrong with the upstream shortwave then its output can be disregarded completely. If its right then cold prospects I'm afraid are likely over.

    Yep, the PV needs to phase with that short wave and hold back its progression eastwards and so pump up the ridge into Greeny. If this does not happen then the pattern flattens and we have to wait for future development upstream.

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    Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

    The UKMO is ghastly for cold and the reason is the lack of a developed shortwave which is expected to engage the PV over in the USA .

     

    If you don't get that interaction upstream then the chances for cold diminish significantly for the UK. If the UKMO is wrong with the upstream shortwave then its output can be disregarded completely. If its right then cold prospects I'm afraid are likely over.

     

     

    GEM different evolution but flattens the upstream: post-14819-0-77342500-1419180369_thumb.p post-14819-0-86261500-1419180399_thumb.p

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    Posted
  • Location: Buxton, Peak District
  • Weather Preferences: Snow
  • Location: Buxton, Peak District

    Some really cold weather heading for the USA as we head in to the New Year week. Over here the models suggest a mixture of unsettled weather and temperatures not far from average.

    Snow risk has reduced again today

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

    Some agreement, the UKM backing up.

     

    A deep depression near the UK around the 27th.

     

    UW144-21.GIF?21-17

    No Greenland Heights at all on this run. Would completely contradict the anomaly charts e.g. NOAA which has a massive positive anomaly near that area for days 6-10.

    GFS, on the other hand, throws in a second bite at the cherry between T192 and T240, with a channel low and resulting easterly. Uppers a bit borderline but snow likely north of the M4 according to this run.

    Main point really is that the "what comes after the storm" bit is far from certain. Cold may possibly persist for a while. Don't adjust your model output bookmarks!

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

    GFS P about to create a beast?? Strange evolution from 252 to 264 says no...

    Edited by Ali1977
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    Posted
  • Location: NR LOURDES SW FRANCE
  • Location: NR LOURDES SW FRANCE

    Yep, the PV needs to phase with that short wave and hold back its progression eastwards and so pump up the ridge into Greeny. If this does not happen then the pattern flattens and we have to wait for future development upstream.

    Yes its all down to that shortwave, the UKMO 00hrs also didn't develop this. Both GFS's do, it's very frustrating because it's just one hurdle after another at the moment.

     

    This whole will it won't it get colder fiasco is like pulling teeth! Hopefully NCEP will disregard the UKMO and the ECM doesn't follow the UKMO.

     

    If anyones interested in why that shortwave is so important rather than doing the same post again I did an earlier one on page 83 post 1658 with images.

     

    We absolutely must have that shortwave develop!

    Edited by nick sussex
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    Posted
  • Location: Brighton, East Sussex
  • Location: Brighton, East Sussex

    Completely disagree.

     

    I think you have made the cardinal sin and commented on a run wayyyy to early.

     

    This chart screams potential if you ask me....

     

    gfsnh-0-186.png?12

    Perhaps yes, but again we are looking at potential in the 8-10 day range, if I had a penny for everytime there's been 'potential' and things don't work out I'd be a very rich man.

    For me we've missed the boat here & the disappointing thing is heights are desperate to build towards greenland there's just a few spoilers as normal when you're trying to get significant cold to an island like ours, all that is not to say another opportunity won't come along soon enough.

    Just to clarify my reasoning behind the 150+ chart is it's an obvious toppler and the coldest uppers are gone as soon as they arrive, a few days ago we were teased into thinking it could be something more.

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    Posted
  • Location: Coulsdon, Surrey
  • Location: Coulsdon, Surrey

    I think the GFS (P) is the one that should be taken the most seriously

    It has stuck to its guns throughout with the great Storm of the 27th and while other models have flip flopped or played catch up the GFS (P) has stood firm, brilliant model

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    Posted
  • Location: Catchgate, Durham,705ft asl
  • Location: Catchgate, Durham,705ft asl

    Looks like the GEM has gone off on one of its "obliterate the PV" runs.

     

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    Posted
  • Location: Kesgrave, just East of Ipswich
  • Weather Preferences: Cold snowy winters, warm dry summers
  • Location: Kesgrave, just East of Ipswich

    Yes its all down to that shortwave, the UKMO 00hrs also didn't develop this. Both GFS's do, it's very frustrating because it's just one hurdle after another at the moment.

     

    This whole will it won't it get colder fiasco is like pulling teeth! Hopefully NCEP will disregard the UKMO and the ECM doesn't follow the UKMO.

     

    If anyones interested in why that shortwave is so important rather than doing the same post again I did an earlier one on page 83 post 1658 with images.

     

    We absolutely must have that shortwave develop!

    I may be barking totally up the wrong tree but I'd like to think that the GFS, being an American model, would have a better handle on shortwaves in the US than the UKMO would?

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

    The UKMO is ghastly for cold and the reason is the lack of a developed shortwave which is expected to engage the PV over in the USA .

     

    If you don't get that interaction upstream then the chances for cold diminish significantly for the UK. If the UKMO is wrong with the upstream shortwave then its output can be disregarded completely. If its right then cold prospects I'm afraid are likely over.

     

    Nick, yet again I am lost, which short wave please and at what time scale are you referring to?

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    Posted
  • Location: Duddingston, Edinburgh
  • Location: Duddingston, Edinburgh

    The 12z's thus far follow the longer term trend we've seen in recent days (as suggested by Cohen etc) for the PV to set up again in NE Canada, heights to lower in GIN sea / NW and a move towards a mobile westerly airmass towards new year

     

    Short term the development and track of the storm on the 27th will be of most interest

    Edited by JoeShmoe
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    Posted
  • Location: Essex, Southend-On-Sea
  • Weather Preferences: Warm, bright summers and Cold, snowy winters
  • Location: Essex, Southend-On-Sea

    The 12z's thus far follow the longer term trend we've seen in recent days (as suggested by Cohen etc) for the PV to set up again in NE Canada, heights to lower in GIN sea / NW and a move towards a mobile westerly airmass towards new year

     

    Short term the development and track of the storm on the 27th will be of most interest

     

    No look very mobile here.

     

    gfs-0-288.png?12

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

    I may be barking totally up the wrong tree but I'd like to think that the GFS, being an American model, would have a better handle on shortwaves in the US than the UKMO would?

    Normally its the GFS that would be most progressive because of its flat bias. The GFS 00hrs run didn't develop the shortwave but since then both GFS's have. I think we'll have to see what the ECM does, if that backs the GFS then I'd disregard the UKMO if not then I'd be worried.

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    Posted
  • Location: Carryduff, County Down 420ft ASL
  • Location: Carryduff, County Down 420ft ASL

    Agreed Joe. A short wintry storm followed by a continued mixed zonality.

    All eyes than remain on the strat for a colder spell after mid January.

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

    Nick, yet again I am lost, which short wave please and at what time scale are you referring to?

    It's the shortwave which runs east across the USA between T96hrs and T120hrs, it then phases with the deep low over ne Canada which holds this back from pushing east so quickly.

     

    You'll see by comparing the UKMO and GFS's the different handling of events upstream which has a big impact on the pattern downstream.

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    Posted
  • Location: Remote North Yorkshire 474ft ASL
  • Weather Preferences: All seasons veteran of the 1981 winter
  • Location: Remote North Yorkshire 474ft ASL

    Agreed, and the UKMO is modelling this at the mo. However, this was the situation for about three weeks earlier this autumn/winter and we had an Easterly draw as you will remember. However, the low strength of the wind (hardly turned a turbine in our turbine infested part of the country!) and the warmth of the continent prevented this from developing into anything of note. As I posted earlier, this seems to be the pattern this winter: missed opportunities that came close but no cigar. I am a believer in patterns and I think this one is set now sadly.

     

    However, I do still have a little hope (and the model biases for Greeny highs in FI are showing themselves again this afternoon) as I remember the pattern change in early January 2011 from the deep cold we had been having to mild mush that lasted the rest of the winter. This could happen in reverse but the signs this year are always fleeting and disappear from run to run.

    agreed to some extent, in 2 weeks time we will all be taking about the next potent low pressure I'm looking forward to next weeks charts.in my studies I look at low pressures over southern Europe as importantly as what's happening over Greenland and associated data.also how the jet stream is projected. I'm taking comfort in this week's chart projections only because it makes forecasting difficult and I like the challenge and ignore most data available to me.to be honest it doesn't help me.i do my own analysis based on T+144 hrs.its hard to explain on text but I find it quite easy to read the charts like a book but that's easy for me to say . I'm not been big headed totally the opposite. It's just my opinion and the way I study. I'm at beverley again tomorrow never good in beverley with a NW wind for snow I like Hunsley tops in my subaru legacy AWD in winter lol
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    I think that chart sums up the medium term nicely.

     

    Completely in the dark. :laugh:

     

    As we all are,

     

    Some decent runs this evening for a NNW flow and 850HPA temps of around -8 to -9c

     

    post-213-0-87754900-1419182388_thumb.jpg

    post-213-0-09575900-1419182404_thumb.jpg

    post-213-0-81192400-1419182293_thumb.gif

     

    post-213-0-80208300-1419182295_thumb.gif

     

    Still very much a possibility of snow streamers on thees charts.

     

    Deal.

     

    Plenty can go wrong of course and normally does.

    Edited by J10
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    Posted
  • Location: Kesgrave, just East of Ipswich
  • Weather Preferences: Cold snowy winters, warm dry summers
  • Location: Kesgrave, just East of Ipswich

    Normally its the GFS that would be most progressive because of its flat bias. The GFS 00hrs run didn't develop the shortwave but since then both GFS's have. I think we'll have to see what the ECM does, if that backs the GFS then I'd disregard the UKMO if not then I'd be worried.

    Hopefully if it's the latest two GFS runs that have picked it up then it has latched on to something and the UKMO has not yet caught up. As you say, we need to see the ECM siding with the Americans on this one!

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    Posted
  • Location: st albans
  • Location: st albans

    Third set and if anything, the spread is increasing in area, especially approaching to our west

    Most recent first

    post-6981-0-24788100-1419182591_thumb.jp

    post-6981-0-74264500-1419182605_thumb.jp

    post-6981-0-81299600-1419182615_thumb.jp

    Edited by bluearmy
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