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Model Output Discussions 12z 08/03/17


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Posted
  • Location: leeds
  • Location: leeds
    1 hour ago, Eugene said:

    Lets not forget @Tamarasaid we might have to see two to three weeks of disappointing weather before we see a marked improvement.

    thats what we hear every year since  day dot... The charts are showing something  decent in the FL and then when it gets closer  to the time frame .the  fine weather gets pushed back and pushed back. before we know its the  second week in June and then people say.. Look  wait for early July..

    We  have seen   that once the weather turns unsettled in the UK in patterns like these.. it takes a a lot to shift it..

    Edited by weatherguru14
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    Much as previously intimated, I'm no longer inclined to posting much at all on these threads, winter or summer, but admittedly the perspectives offered sometimes prove too much to resist responding to

    Do they?  Oh ok, right you are then. You could of course have quoted said "way of the pear" musings by way of illustration - but I accept that would conflict with the real purpose of the post and

    So, the steadily improving picture emerges, from a sea of apparent doubt, and as suggested is timed quite nicely for the approach of summer That background ENSO neutral > weak Nino signal impr

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    Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth
    1 hour ago, knocker said:

    Well the south east should get some rain on Wednesday

    gfs_ptype_slp_eur3_10.thumb.png.0da88f5b96503807e9c4749d9e528b0b.pngPPVK89.thumb.gif.5b891cd1bf7a1c40bd1142c384246f6a.gif

    Would be very welcome in these parts!! Looking through a number of models, fair agreement on between 25mm and 50mm. With water running off dry roads and drains perhaps blocked from the build up of 2 months of junk that hasn't been washed away, I imagine there may be one or two tiny floods on the roads.

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    Posted
  • Location: Camborne
  • Location: Camborne
    24 minutes ago, Man With Beard said:

    Would be very welcome in these parts!! Looking through a number of models, fair agreement on between 25mm and 50mm. With water running off dry roads and drains perhaps blocked from the build up of 2 months of junk that hasn't been washed away, I imagine there may be one or two tiny floods on the roads.

    The ecm has quite a swathe of rain from about 12z Weds to 12z Thursday mainly concentrated south east of a line Dorset to the Humber with the heaviest in the Wash/Norfolk area with certainly some significant amounts in some areas.. Can't post the charts.

    Edited by knocker
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    Posted
  • Location: Camborne
  • Location: Camborne

    A quick glance at the latest EC46 means update, albeit I appreciate that many think these a waste of space. Just the seven day chunks rather than a day to day appraisal

    In the 7-14 range the main features are a fairly intense upper low northern Russia and associate trough. positive anomalies over south east Greenland/Iceland area and low pressure to the south west. All of this leaves the UK in a very slack weather pattern, virtually in col territory. so a fairly quiet period with temps a little above average.

    In the 11-18 period things have predictable moved on a tad. The trough to the east has moved a little closer and the Atlantic trough now dominates the eastern Atlantic and thus a westerly upper flow and a return to more unsettled weather with temps dipping below average.

    The 14-21 period sees the trough to the east decline but still the eastern Atlantic trough dominated so still unsettled with temps below average.

    The 18-25 period sees the removal of the trough to the east but the Atlantic still trough dominate and thus a continuation of the westerly upper flow with unsettled weather and temps slightly depressed.

    One hopes this very general overview is wrong.

    Onwards and upwards.

    The wave forming on the front tracks north east tomorrow bringing some much needed rain to the SE quadrant of the country before tracking into Scandinavia. Then begins the transition with the Azores ridging in mid Atlantic and the trough to the NW sliding SE to be over Ireland by 00z on Saturday. This merely reinforcing the showery conditions that have been prevailing with average temps.

    gfs_z500a_natl_17.thumb.png.3e9ffa5f2d014f139f4a1cbef55e3343.pnggfs_ptype_slp_eur3_17.thumb.png.3ee054561d90dd3808d26ccb06dc1aa6.png

    Now begins a few days that requires little analysis. The area of low pressure remains in the vacinity of the UK with the ridge to the west until towards the end of next week when it moves away east and the next low tracks in from the south west. This fits quite well with the anomaly.

    Thus a continuation of  the showery regime but perhaps not that frequent in many areas and although the temps are no great shakes with the light winds any extended sunny interval should be quite pleasant.

    gfs_ptype_slp_eur3_29.thumb.png.6fa88eef09bcd60dcfc3dedb3bd3f56e.pnggfs_ptype_slp_eur3_40.thumb.png.2286a0014548018c4239c6fd27992418.png

     

     

    Edited by knocker
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    Posted
  • Location: Camborne
  • Location: Camborne

    The ecm has the low over the UK at the weekend drifting NW and another low tracking in from the south west by 00z Monday. It then phases them all together to form a new area of low pressure covering the UK by 00z Tuesday. This will produce heavy showers in many areas and some prolonged periods of rain albeit temps might be slightly above average. The depression then move off to the north east leaving the UK in a north westerly airstream

    ecm_mslp_uv850_natl_8.thumb.png.9dae5ea0c40bea5a029c61248f82aa98.pngecm_mslp_uv850_natl_10.thumb.png.2a89c70818dcec9000bbfde2065c3aa5.png

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    Posted
  • Location: Wantage, Oxon
  • Weather Preferences: Hot, cold!
  • Location: Wantage, Oxon

    Something about the chart below bothers me.  It is the tercile probability plots from GloSea5 for the summer months for 500 hPa heights:

    3up_20170501_z500_months24_global_prob_public.thumb.png.274cff1970a41203d8e6c29432b6fc49.png

    I accept that these probabilities are derived from a large number of model runs and averaged over a 3 month period, but without being able to see the individual evolutions, I find the plot is hard to interpret.  It seems to depict a rather extreme position, with higher probability of higher than average heights over pretty much the entire globe.  Does anyone know what might be causing this – is the averaging process masking everything but significant seasonal drivers? – is this rather extreme-looking position a hangover from last year’s El Nino, for example?  

    Finally, a few posters have expressed concern that we may be headed for a 2007/12 type summer – the plots aren’t available for 2007, but for 2012 the corresponding plot from GloSea4 (as I think it was in those days) is as follows:

    3up_20120501_z500_months24_global_prob_public.thumb.png.2fe590c57e0e1b6e2784ff8bb208554b.png

    It couldn’t look more different to this year’s.  GloSea5 clearly sees this summer very differently to how it saw 2012 at the same time 5 years ago, so I see a repeat of 2012 as rather unlikely. 

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    Posted
  • Location: Camborne
  • Location: Camborne

    The EPS 6-10 means this morning are not looking too bad but not surprisingly the further outlook is a trough in the Atlantic with the upper flow WSW

    ecm_eps_t850a_5d_nh_11.thumb.png.0e92de823bd8d79e1bac3bb057ff75a6.png

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    Posted
  • Location: Exeter, Devon, UK. alt 10m asl
  • Location: Exeter, Devon, UK. alt 10m asl
    53 minutes ago, Mike Poole said:

    Something about the chart below bothers me.  It is the tercile probability plots from GloSea5 for the summer months for 500 hPa heights:

    3up_20170501_z500_months24_global_prob_public.thumb.png.274cff1970a41203d8e6c29432b6fc49.png

    I accept that these probabilities are derived from a large number of model runs and averaged over a 3 month period, but without being able to see the individual evolutions, I find the plot is hard to interpret.  It seems to depict a rather extreme position, with higher probability of higher than average heights over pretty much the entire globe.  Does anyone know what might be causing this – is the averaging process masking everything but significant seasonal drivers? – is this rather extreme-looking position a hangover from last year’s El Nino, for example?  

    Finally, a few posters have expressed concern that we may be headed for a 2007/12 type summer – the plots aren’t available for 2007, but for 2012 the corresponding plot from GloSea4 (as I think it was in those days) is as follows:

    3up_20120501_z500_months24_global_prob_public.thumb.png.2fe590c57e0e1b6e2784ff8bb208554b.png

    It couldn’t look more different to this year’s.  GloSea5 clearly sees this summer very differently to how it saw 2012 at the same time 5 years ago, so I see a repeat of 2012 as rather unlikely. 

    I've raised a query before in regard to anomaly charts - what are the anomalies being measured against?  Could it be a rolling average adjusted to regional variations or a single arbitrary global value- eg 1000mb for pressure charts?  Would make a big difference and no one really seemed to have an answer for certain.  I could email the relevant bodies that issue these charts but life is too short to be honest, certainly in regards to getting that hung up on a crude/broad brush predictive tool.

    Looking at the two charts posted in regards to our neck of the woods:-

    The May 2012 looked pretty darn close to the money in predicting the poor UK summer, not sure how it fared globally?  

    The current one seems to suggest (to my very untrained eye) above avg probability of long wave troughs for Alaska/Canada border, mid Atlantic and Eastern Russia ca 40 E so hopefully if it will be equally accurate as the 2012 one and the trough being modeled for the UK for the foreseeable will shove off come June.

     

     

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

    an odd comment to make

      I could email the relevant bodies that issue these charts but life is too short to be honest, certainly in regards to getting that hung up on a crude/broad brush predictive tool.

    That is if you wish to find out just what they do mean and how, for example, UK Met, produce their charts. It would be very interesting if you can get the front desk to pass your query on to the relevant area what they say?

    You could also try their web site and see what they are currently writing about this model?

    Is this any help to you, from just browsing their web site?

     

    http://www.metoffice.gov.uk/research/modelling-systems/unified-model/climate-models/glosea5

    Edited by johnholmes
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    Posted
  • Location: Lytchett Matravers - 301 ft ASL
  • Weather Preferences: Snowy Winters, Torrential Storm Summers
  • Location: Lytchett Matravers - 301 ft ASL
    19 minutes ago, knocker said:

    accumprecip_d02_46.thumb.png.fd7713d5861f0778312ceb910b270a21.png

    we've not seen totals like that for quite some time in these areas, so I would imagine surface flooding is a real possibility, from Dorset/Hampshire NE to south Lincs. Evening commute could be interesting/hazardous  

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    Posted
  • Location: Exeter, Devon, UK. alt 10m asl
  • Location: Exeter, Devon, UK. alt 10m asl
    38 minutes ago, johnholmes said:

    an odd comment to make

      I could email the relevant bodies that issue these charts but life is too short to be honest, certainly in regards to getting that hung up on a crude/broad brush predictive tool.

    That is if you wish to find out just what they do mean and how, for example, UK Met, produce their charts. It would be very interesting if you can get the front desk to pass your query on to the relevant area what they say?

    You could also try their web site and see what they are currently writing about this model?

    Is this any help to you, from just browsing their web site?

     

    http://www.metoffice.gov.uk/research/modelling-systems/unified-model/climate-models/glosea5

    Hi John, it's more a case of i'm kinda curious but certainly not to the point of spending a great deal of time, that i do not really have, getting to the bottom of every individual set of charts produced.  This is especially the case of the very long range ones which we will all view whilst taking the appropriately large pinch of salt.  I also suspect the baseline will vary from organisation to organisation, chart type to chart type and over time as what is accepted practice becomes refined by R&D?  

    I would like to think it would be good practice to at least have a legend saying what the baseline/ref is for charts like this, but i say this from the perspective of someone, a very casual dabbler if you will, who is not the intended audience.  Those who actively work with these products probably already know these details and it is therefore superfluous.

     

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

    Tomorrow's rain - quite a lot of divergence between the latest models at just T24 or even less.

    The latest ARGEPE has the heaviest stuff through Devon up to Humber. The latest GFS is much, much further east.

    Nowcast here we come!

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    Posted
  • Location: Cambridge, UK
  • Weather Preferences: Anything out of the ordinary!
  • Location: Cambridge, UK

    I'm not sure whether they are that much different in their overall outcome...synoptically quite similar, just ukmo get the low in a tad quicker. They are both heading down the same track either way....unsettled for another week. Oh the joys.

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    Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

    Both ECM and GFS painting a rather unsettled picture for the foreseeable, something we haven't seen for quite some time now. Slow moving trough anchoring down from the NW is set to dominate affairs, going nowhere fast, with further low pressure ready to attack from the west as we move through next week. I seem remember May 2008 did this king of flip, with a very warm settled first half followed by a much wetter predominantly unsettled second half - just an observation..

    The rain will be welcomed by some, and it may salvage imminent threat of water conservation measures. Some places tomorrow could end up with levels close to the May average. We had over an inch yesterday, highest daily total since mid-late March.

    Hoping the unsettled phase squeezes itself out by Bank Holiday weekend.. the best of the bunch in my opinion, and the start of the best time of year late May/early June - start of the summer and generally a good feeling in the air.

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    Posted
  • Location: Camborne
  • Location: Camborne

    The anomalies are all in the same ball park this evening albeit disagreeing on detail.

    The key features are a quite intense low N. Russia with associated trough, high pressure over the Pole, some positive anomalies around Iceland which tends to bloom into ridging over the UK, and the trough in the western Atlantic. Thus trending towards a fairly quiet period of weather in this period with temps a little above average. This may well last a couple of days into the next period before the trough in the west takes closer order.

    ecm_eps_z500a_5d_nh_11.thumb.png.2195b238268f722a3780b3f320deb8ad.pngecm_eps_t850a_5d_nh_11.thumb.png.2a06a30c823537407dd263ee9792b01c.pnggefs_z500a_5d_nh_41.thumb.png.e4ee746888dd879ea6edd00841b5b862.png

    610day_03.thumb.gif.af28e01f105fb28f030065157ae8e19a.gif

     

    Edited by Paul
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    Posted
  • Location: Ward Green barnsley
  • Weather Preferences: Snow freezing fog heatwave thunderstorm
  • Location: Ward Green barnsley

    Don't be so down beat ens showing higher temps from 23rd ish on 12z and ecm shows high building at day 10 fantasy but its a start

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    Posted
  • Location: Camborne
  • Location: Camborne

    Firstly today will be wet for much of England and east wales as the wave depression tracks north east into the North Sea

    PPVE89.thumb.gif.cb4504827f1b333bb1dff0abc96c3f29.gifaccumprecip_d02_36.thumb.png.567e519b311b5e2b8b24efa341839b2f.png

    And on to the gfs. By midnight Friday the main Atlantic low has drifted south east thus a a large area of low pressure over the UK introducing a showery/sunny intervals regime, whilst the Azores ridges in the west.

    gfs_ptype_slp_eur3_13.thumb.png.fd148a5bea1f700c14cd0d1837fc04c9.png

    But the Atlantic ridge is temporarily breeched by upstream energy tracking east and' topping' up the upper low over the UK which reinvigorates the surface low which by 12z Sunday is 995mb NW of Ireland with most of the UK in a showery south westerly airstream with temps around average.

    gfs_z500a_natl_17.thumb.png.7c4149a583b10a77b3f50ee6386b86da.pnggfs_ptype_slp_eur3_19.thumb.png.18a34c7dabab539b52c573c1c865ecc6.png

    From this point the two lows phase together as the Azores once more struggles to ridge north and by 12z there is a more organized surface low 992mb centred over Ireland which, as well bringing on more showers and perhaps longer periods of rain, also possibly some quite strong winds in the SW/S of England

    gfs_z500a_natl_27.thumb.png.bb906f84d5a8153b55de672d2b92f034.pnggfs_ptype_slp_eur3_27.thumb.png.33dca1c41e42914f33f36b9f6536ba48.png

    The low slowly fills and drifts east leaving the UK under a very slack pressure gradient with temps, generally around average, but with the usual geographic variations.

    gfs_ptype_slp_eur3_39.thumb.png.b2de8cea21fcc0d43dff3dd8cb17c5b8.png

    Edited by knocker
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    Posted
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.
  • Location: Derbyshire Peak District South Pennines Middleton & Smerrill Tops 305m (1001ft) asl.

    No more on BBC or Meto public forecast in here please.

    Thanks

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    Posted
  • Location: Camborne
  • Location: Camborne

    I should have mentioned in my brief overview of the gfs tha small depression that tracks north fom France early Friday into the North Sea. It could well impact the far south east with some thundery activity?

    ecm_mslp_uv850_eur_3.thumb.png.94ed614d1a84616830a93de5f8f91a09.png

    The ecm has the weekend improving as it goes along with firstly HP building from the south west and then to the east. So Sunday/Monday looking okay before the Atlantic low arrives on Tuesday.

    ecm_mslp_uv850_natl_6.thumb.png.bb2062435d05128a3816e8b075f274d2.pngecm_mslp_uv850_natl_8.thumb.png.cd80aa9c038bfde4e767a4f8427c7053.png

    So even by the weekend the the gfs and ecm differ on the depth and position of the low to the NW and thus the influence of ridging from the south west.

    Edited by knocker
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    Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

    Something a bit drier and warmer returning to the south and SE next week?

    UKMOPEU00_96_1.pngUKMOPEU00_120_1.pngUKMOPEU00_144_1.png

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    Posted
  • Location: Cambridge, UK
  • Weather Preferences: Anything out of the ordinary!
  • Location: Cambridge, UK

    This was mentioned SS - a brief bump of high pressure could give a couple of fine days in the SE. Unsure as to the evolution after, but it would appear low pressure will take control once more...

    gefsens850london0.png

    The number of warmer solution (above 10c at 850) have all vanished this morning, with quite a closer spread of solutions. Looks around average to me, and gardeners will probably welcome those ppn spikes shown! Been dry as a bone for a long time!

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