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uk.sci.weather (UK Weather) (uk.sci.weather) For the discussion of daily weather events, chiefly affecting the UK and adjacent parts of Europe, both past and predicted. The discussion is open to all, but contributions on a practical scientific level are encouraged. |
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#11
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comp.john wrote:
On 2009-12-07, John Hall wrote: The GFS Ensemble 850mb temps for London are now looking decidedly chilly: http://91.121.93.17/pics/MT8_London_ens.png What do the coloured P numbers mean down the left side of the chart? I think they are the 20 ensembly members, basically 20 different runs. If they all follow the same line then confidence is higher. e.g.: http://www.wetterzentrale.de/pics/senspanel2401.html This shows 20 versions of the same day.... All others can be found he http://www.wetterzentrale.de/topkarten/fsenseur.html -- Keith (Southend) http://www.southendweather.net e-mail: kreh at southendweather dot net |
#12
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In article ,
comp.john writes: On 2009-12-07, John Hall wrote: The GFS Ensemble 850mb temps for London are now looking decidedly chilly: http://91.121.93.17/pics/MT8_London_ens.png What do the coloured P numbers mean down the left side of the chart? Good question. Hopefully someone else will know, as I don't have a clue. -- John Hall "[It was] so steep that at intervals the street broke into steps, like a person breaking into giggles or hiccups, and then resumed its sober climb, until it had another fit of steps." Ursula K Le Guin "The Beginning Place" |
#13
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On Mon, 07 Dec 2009 22:04:40 +0000, John Hall wrote:
In article , comp.john writes: On 2009-12-07, John Hall wrote: The GFS Ensemble 850mb temps for London are now looking decidedly chilly: http://91.121.93.17/pics/MT8_London_ens.png What do the coloured P numbers mean down the left side of the chart? Good question. Hopefully someone else will know, as I don't have a clue. I've always assumed that they're simply a guide to which perturbation is shown in which colour. -- Bewdley, Worcs. ~90m asl. |
#14
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On Dec 7, 11:42*pm, David Buttery wrote:
On Mon, 07 Dec 2009 22:04:40 +0000, John Hall wrote: In article , *comp.john writes: On 2009-12-07, John Hall wrote: The GFS Ensemble 850mb temps for London are now looking decidedly chilly: http://91.121.93.17/pics/MT8_London_ens.png What do the coloured P numbers mean down the left side of the chart? Good question. Hopefully someone else will know, as I don't have a clue.. I've always assumed that they're simply a guide to which perturbation is shown in which colour. -- Bewdley, Worcs. ~90m asl. Yes, as far as I know. It's so you can identify which run is which. |
#15
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"Martin Rowley" wrote ...
"comp.john" wrote in message ... On 2009-12-07, John Hall wrote: The GFS Ensemble 850mb temps for London are now looking decidedly chilly: http://91.121.93.17/pics/MT8_London_ens.png What do the coloured P numbers mean down the left side of the chart? ... tags identifying the individual perturbation outcome depicted on the composite plume. P=0 is the first perturbation, P=1 is the second and so on. The colours match the individual (thin) lines on the chart. Useful if you're trying to identify clustering of the members of the plume-set. .... I should have added that for each main time-step of the ensemble run, a set of 'postage stamps' will be available. They're called that because they look like a sheet of stamps you might see in a post office. Usually (based on the EC output), for the main VT times, each 'postage stamp' sheet will show the 'operational' run mslp pattern, the 'control' run mslp pattern, and for each perturbation, the model's idea of what the mslp pattern would be that produced that individual outcome. So, the analyst would look as these data - and want, say to investigate why P16 was markedly colder than the rest, and view the mslp (and perhaps other diagnostics) that are attached to that particular outcome. We don't (AFAIK) see these on the open 'web', so in a sense the coloured 'P' lines/numbers aren't of high relevance. Martin. -- Martin Rowley West Moors, East Dorset (UK): 17m (56ft) amsl Lat: 50.82N Long: 01.88W NGR: SU 082 023 |
#16
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On 8 Dec, 12:03, "Martin Rowley"
wrote: "Martin Rowley" wrote ... "comp.john" wrote in message ... On 2009-12-07, John Hall wrote: The GFS Ensemble 850mb temps for London are now looking decidedly chilly: http://91.121.93.17/pics/MT8_London_ens.png What do the coloured P numbers mean down the left side of the chart? ... tags identifying the individual perturbation outcome depicted on the composite plume. P=0 is the first perturbation, P=1 is the second and so on. The colours match the individual (thin) lines on the chart. Useful if you're trying to identify clustering of the members of the plume-set. ... I should have added that for each main time-step of the ensemble run, a set of 'postage stamps' will be available. They're called that because they look like a sheet of stamps you might see in a post office. Usually (based on the EC output), for the main VT times, each 'postage stamp' sheet will show the 'operational' run mslp pattern, the 'control' run mslp pattern, and for each perturbation, the model's idea of what the mslp pattern would be that produced that individual outcome. So, the analyst would look as these data - and want, say to investigate why P16 was markedly colder than the rest, and view the mslp (and perhaps other diagnostics) that are attached to that particular outcome. We don't (AFAIK) see these on the open 'web', so in a sense the coloured 'P' lines/numbers aren't of high relevance. Martin. -- Martin Rowley West Moors, East Dorset (UK): 17m (56ft) amsl Lat: 50.82N * Long: 01.88W NGR: SU 082 023- Hide quoted text - - Show quoted text - I'm still not convinced the cold next week is going to be anymore than sleet, with any snow quickly melting on the ground, well at least at my neck of the woods :-( Obviously at longer range gfs goes off at a tangent, but I'm not really taking then serious atm. Keith (Southend) |
#17
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Martin Rowley wrote:
"Martin Rowley" wrote ... "comp.john" wrote in message ... On 2009-12-07, John Hall wrote: The GFS Ensemble 850mb temps for London are now looking decidedly chilly: http://91.121.93.17/pics/MT8_London_ens.png What do the coloured P numbers mean down the left side of the chart? ... tags identifying the individual perturbation outcome depicted on the composite plume. P=0 is the first perturbation, P=1 is the second and so on. The colours match the individual (thin) lines on the chart. Useful if you're trying to identify clustering of the members of the plume-set. ... I should have added that for each main time-step of the ensemble run, a set of 'postage stamps' will be available. They're called that because they look like a sheet of stamps you might see in a post office. Usually (based on the EC output), for the main VT times, each 'postage stamp' sheet will show the 'operational' run mslp pattern, the 'control' run mslp pattern, and for each perturbation, the model's idea of what the mslp pattern would be that produced that individual outcome. So, the analyst would look as these data - and want, say to investigate why P16 was markedly colder than the rest, and view the mslp (and perhaps other diagnostics) that are attached to that particular outcome. We don't (AFAIK) see these on the open 'web', so in a sense the coloured 'P' lines/numbers aren't of high relevance. Martin. The GFES 'postage stamp' sheets are available at http://www.netweather.tv/index.cgi?a...wer;type=panel They are in 6-hourly time-steps out to T+384. Norman |
#18
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On 2009-12-08, Martin Rowley
wrote: [...] cool, that's easy to follow. Thanks for the explanation. -- comp.john |
#19
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In article ,
Jon O'Rourke writes: "comp.john" wrote in message ... How does 850mb temp correspond with surface temp at this time of year? is -5 @ 850mb 0C at the surface? -- comp.john It's not really the best guide for surface temperatures as the boundary layer conditions at this time of year can heavily modify a direct adiabatic translation. However, to give you some idea, when 850mb temperatures were around -4 around a week ago daytime surface temperatures were in the +4 to +6 ballpark. And the long-term mean 850mb for this time of year is about -1, as shown by the white line on the GFS ensemble temperatures. The mean maximum surface temperature at this time of year would be about 8, again indicating a difference between the 850mb level and the surface of about 8 degrees on average. -- John Hall "[It was] so steep that at intervals the street broke into steps, like a person breaking into giggles or hiccups, and then resumed its sober climb, until it had another fit of steps." Ursula K Le Guin "The Beginning Place" |
#20
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On Dec 8, 12:03*pm, "Martin Rowley"
wrote: "Martin Rowley" wrote ... So, the analyst would look as these data - and want, say to investigate why P16 was markedly colder than the rest, and view the mslp (and perhaps other diagnostics) that are attached to that particular outcome. We don't (AFAIK) see these on the open 'web', so in a sense the coloured 'P' lines/numbers aren't of high relevance. We do - as well as the "postage stamps" Norman mentioned, you can see each GFS ensemble member in detail at Meteociel. http://www.meteociel.com/modeles/gefs_cartes.php Click the numbers +1 to +20 where it says "Perturbations", or "Moy" for the ensemble mean. |
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