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Model Output Discussion - 31/8/14 Onwards.


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Posted
  • Location: Camborne
  • Location: Camborne

The anomaly charts are more or less on the same wavelength apart from the GFS. The key to next weekends temps and weather would appear to to be the exact position of the upper and surface low to the south west. The ECM ops take on this.

 

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

For this morning's output there are subtle differences to the higher pressure over the UK at D7, but it remains a settled week ahead:

 

 

ECMpost-14819-0-14365000-1410072429_thumb.g  GFSpost-14819-0-09410300-1410072447_thumb.p  GEM: post-14819-0-05163200-1410072465_thumb.p

 

GEM at D10 still remains relatively settled in a benign setup: post-14819-0-03645800-1410072585_thumb.p

 

GFS op also has the UK being driven by higher pressure, more of a Scandi High: 

 

post-14819-0-14120800-1410072675_thumb.p  GEFS mean: post-14819-0-54879900-1410072750_thumb.p

 

Not all the GEFS support the extension of higher pressure but each run extends the current setup and the trend (highest cluster by far now at D10) is for the settled weather to continue. Less scatter on the pressure chart for London and it is showing 7 dry days upcoming:

 

post-14819-0-38835500-1410073452_thumb.g  Temps average to above: post-14819-0-02465600-1410073548_thumb.g

 

ECM at D10 has the UK in a shallow warm  trough with a split jet and the Atlantic remains diverted from our region:

 

 post-14819-0-37427300-1410073266_thumb.g  post-14819-0-95200400-1410073299_thumb.g

 

Looking good for more of the same and even the D13 mean on the GEFS still has he main player as the Azores so FI looking promising: post-14819-0-89579300-1410073703_thumb.p

 

 

 

 

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Posted
  • Location: chellaston, derby
  • Weather Preferences: The Actual Weather ..... not fantasy.
  • Location: chellaston, derby

well explained and illustrated phil-thank you.

I would prefer folk to look at the 500mb pattern and not make anything of the anomaly feature until they have become very well used to what they can and cannot show. In an earlier post, some days ago, I suggested that unless the anomaly is larger than 60 be it + or - then it is not really showing anything of note.

One other point an anomaly say of 90 +ve does not mean the wind will flow in any particular direction as I have seen someone in the winter thread suggesting. A lot more complicated than that.

 

it took an experienced person like you 2 years to understand them fully john, please feel free anytime to correct anything i say that is inaccurate, i and others are still learning!

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

UKMO shows high pressure dominating to at least next Saturday chilly at night with some mist or fog patches developing but these should soon burn off with variable cloud cover by day

 

U96-21UK.GIF?07-07U120-21UK.GIF?07-07U144-21UK.GIF?07-07

 

Warm by day at first but temperatures could fall slightly by the end of next week for some parts but still very pleasant by day for the time of year

 

UW96-7.GIF?07-07UW120-7.GIF?07-07UW144-7.GIF?07-07

Edited by Summer Sun
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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

I agree with summer sun, it looks warm and settled for the foreseeable future..the friendly face of autumn :)

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

Just going back to the use of anomaly charts,and its easy to be fooled by them if not careful.

 

Take the ECM ensemble mean at +72 as an example:

 

 

High pressure centered to the north? ..Easterly wind?...

 

 

nope,high pressure slap bang over the UK and looks very pleasant indeed.

 

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

I agree with summer sun, it looks warm and settled for the foreseeable future..the friendly face of autumn :)

 

 

Last week the highs were about 2.14c above historical averages for the Midlands area (Sutton Coldfield). Though the CET to the 5th is less than that at +1.5c. Looking at the models for the current week I am not sure they will match that. Not that I am complaining, it will be pleasant enough once the early morning cloud has burnt off (feel warm in the sun). Probably a combination of the wind coming from a cooler direction (easterly, dragging in cloud) and the uppers being cool to average:

 

post-14819-0-52494800-1410082253_thumb.g  post-14819-0-62885400-1410082263_thumb.g

 

Also nights look like being below average for the time of year especially rural N and W, though sunnier in the west as a whole.

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

If anything, the Ecm 00z ensemble mean is even more bullish about a prolonged settled outlook than it was yesterday. I believe we are in for a decent spell of anticyclonic weather with an increasingly blocked looking pattern, no hint whatsoever of the atlantic waking up, the models this morning are painting a benign, fine and rather warm picture for the foreseeable future with locally chilly nights with fog patches. I'm happy to wait until october for the darker side of autumn to show itself. :)

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

it took an experienced person like you 2 years to understand them fully john, please feel free anytime to correct anything i say that is inaccurate, i and others are still learning!

 

I am still not utterly confident in using them at times and they do need to be used in conjuction with other models that are valid in the same time period. It is incredibly complex and that is why we employ very well qualified folk to look at every output, use their knowledge and interpret all the data to produce forecasts for us on the ground. As comments on Net Wx show they do not always get it right.

There is a very good example post 134 (Cloud 10) showing how easily it can be to be mislead by the anomaly part of a chart. Just where the surface features come to reside beneath the upper anomaly is highly complex and certainly not straightforward. I believe knocker showed another example earlier from some work I did a year or two ago.

I am pushed for time so cannot give an in depth reply yet but I will try and find time to show how they can mislead if the anomaly side only is used but I have no idea when I can dig out data to produce this.

It is great to see folk using them and I hope I do not come across as a clever clogs if I try gently to suggest that what is posted after showing an anomaly chart may not be correct. We all learn from one another professional and amateur and we all love this highly complex and still at times unpredictable hobby called the weather.

Edited by johnholmes
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Posted
  • Location: Bristol
  • Location: Bristol

Following on from the midnight run, the 6z GFS is a lot more unsettled albeit in FI. With the ens offering little support to such an evolution, it appears mere fantasy at this point.(in saying that, tho, the latest GEFS update does give indications of a more zonal setup in/around 21/22 Sep). And with the transition in seasons now in full swing, I do expect & hope, we see the current pattern broken during the latter stages of Sept.

 

gfs-0-288_vwu1.pnggfs-0-348_ons5.png

 

GFS 6z t288 & 348

Edited by draztik
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Posted
  • Location: Camborne
  • Location: Camborne

I am still not utterly confident in using them at times and they do need to be used in conjuction with other models that are valid in the same time period. It is incredibly complex and that is why we employ very well qualified folk to look at every output, use their knowledge and interpret all the data to produce forecasts for us on the ground. As comments on Net Wx show they do not always get it right.

There is a very good example post 134 (Cloud 10) showing how easily it can be to be mislead by the anomaly part of a chart. Just where the surface features come to reside beneath the upper anomaly is highly complex and certainly not straightforward. I believe knocker showed another example earlier from some work I did a year or two ago.

I am pushed for time so cannot give an in depth reply yet but I will try and find time to show how they can mislead if the anomaly side only is used but I have no idea when I can dig out data to produce this.

It is great to see folk using them and I hope I do not come across as a clever clogs if I try gently to suggest that what is posted after showing an anomaly chart may not be correct. We all learn from one another professional and amateur and we all love this highly complex and still at times unpredictable hobby called the weather.

 

Thanks John. As you say highly complex and I don't begin to have anywhere near a complete understanding of it. I would think (nearly always fatal) that you might easily get a large discrepancy regarding wind direction when a surface low was displaced in relation to the anomaly upper low.

Edited by knocker
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Posted
  • Location: Cheddington, Buckinghamshire
  • Weather Preferences: Winter: Cold & Snowy, Summer: Just not hot
  • Location: Cheddington, Buckinghamshire

Just a gentle reminder that this isn't the place to be discussing one's weather preferences. Thank you.

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Posted
  • Location: Cleeve, North Somerset
  • Weather Preferences: Continental winters & summers.
  • Location: Cleeve, North Somerset

Following on from the midnight run, the 6z GFS is a lot more unsettled albeit in FI. With the ens offering little support to such an evolution, it appears mere fantasy at this point.(in saying that, tho, the latest GEFS update does give indications of a more zonal setup in/around 21/22 Sep). And with the transition in seasons now in full swing, I do expect & hope, we see the current pattern broken during the latter stages of Sept.

 

gfs-0-288_vwu1.pnggfs-0-348_ons5.png

 

GFS 6z t288 & 348

 

Not too dissimilar from this:

 

Rrea00120110912.gif

 

A few hurdles to cross before we get there though. The reliable timeframe is characterised by at least settled if not anticyclonic charts with pressure falling slowly from next weekend with both the GFS and ECM agreeing so far on a breakdown into the week after that. First, a slack low from the south acting as an entry for a larger low (as you've posted) from the west later in the week. Before then however it does look like another settled week to come before anything of interest pops up. I'd say it will probably be a sunnier week than last week too.

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

UKMO continues to show high pressure dominating

 

U96-21UK.GIF?07-18U120-21UK.GIF?07-18U144-21UK.GIF?07-18

 

Warm by day but chilly at night (t144 850's unavailable at the time of posting)

 

UW96-7.GIF?07-18UW120-7.GIF?07-18

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Posted
  • Location: Evesham/ Tewkesbury
  • Weather Preferences: Enjoy the weather, you can't take it with you 😎
  • Location: Evesham/ Tewkesbury

Fine conditions for just about all in the week ahead, but some cold nights with the proverbial Autumn fog. Its when we come to next weekend and then the gfs /ecm differ. Gfs is staunch on its output with high pressure in control throughout, Ecm has fronts moving into the southwest by then ,which is inline with the metoffice updates. I would not be surprised to see the gfs win out on this one! :cc_confused: But then I could be Very wrong!

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Edited by ANYWEATHER
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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

Tonight's Ecm 12z op run shows an anticyclonic week ahead and gradually warmer too, +10 T850 hPa pushing across most of the uk later in the run, so we could be looking at mid 20's celsius later, pressure eventually falls across the south / sw as a trough edges north from france so there could be a thundery breakdown between days 8-10 but overall it's a continuation of the summery weather which most of have had since the first day of this meteorological autumn and indeed more enhanced continental warmth could be on the way.

 

The week ahead looks pleasantly warm with sunny spells and variable cloud, the cloud amounts are the only headache for forecasters to worry about. It looks like winds will be light but later on a SE'ly breeze could set up which will help to draw that warmer air our way, initially, where skies stay clear at night, locally chilly with fog patches and this type of weather should persist until into next weekend, beyond that, the north / ne could stay fine and warm with higher pressure to the NE, the south becoming very warm and more humid with hazy sunshine and an increased potential for thundery showers.

 

:)  plenty to smile about for those of us who enjoy fine and warm weather :)

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Posted
  • Location: Peterborough
  • Weather Preferences: Snow and frost in the winter. Hot and sunny, thunderstorms in the summer.
  • Location: Peterborough

Well at around day 9/10, the ECM and GEM do show a potential breakdown route developing as we develop a more significant Atlantic trough which engages the stationary low to our south west.

gem-0-240.png?12

ECM1-240.GIF?07-0

This could bring a steady return to unsettled conditions, but it is so far away that this could be reduced to a non-event. Otherwise the weather will remain settled for the foreseeable future.

There are subtle hints in the GFS ens that there could be a return to a more westerly and average pattern from day 10 and beyond, but a long way to go, especially as this has happened before a week back for which I was absent from these forums.

Edited by Captain shortwave
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Posted
  • Location: East Ham, London
  • Location: East Ham, London

http://modeles.meteociel.fr/modeles/gfs/runs/2014090712/gfs-0-96.png?12

 

Evening all :)

 

One of the problems of looking at charts like these is that they don't always tell the whole story. Superficially, the chart looks settled so you might think dry, sunny and warm BUT the other possibility is dull and overcast and as someone living to the east of London, these set-ups don't always deliver the warmth and the sunshine.

 

In truth, we need a stronger E'ly or ESE'ly breeze to bring in some drier, clearer air. The Met Office forecast shows humidity rising from 54 to 62 per cent between Wednesday and Thursday so I'm not optimistic for sunshine and without that sunshine, temperatures will be average at best.

 

http://www.meteociel.fr/modeles/ecmwf/runs/2014090712/ECM1-96.GIF?07-0

 

ECM almost identical - oddly enough, the breakdown, by providing that impetus of breeze, might start by improving the situation before the more unsettled conditions spread in.

 

This happens in winter - initial clear conditions are replaced by cloud in the absence of a breeze.

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

http://modeles.meteociel.fr/modeles/gfs/runs/2014090712/gfs-0-96.png?12

 

Evening all :)

 

One of the problems of looking at charts like these is that they don't always tell the whole story. Superficially, the chart looks settled so you might think dry, sunny and warm BUT the other possibility is dull and overcast and as someone living to the east of London, these set-ups don't always deliver the warmth and the sunshine.

 

In truth, we need a stronger E'ly or ESE'ly breeze to bring in some drier, clearer air. The Met Office forecast shows humidity rising from 54 to 62 per cent between Wednesday and Thursday so I'm not optimistic for sunshine and without that sunshine, temperatures will be average at best.

 

http://www.meteociel.fr/modeles/ecmwf/runs/2014090712/ECM1-96.GIF?07-0

 

ECM almost identical - oddly enough, the breakdown, by providing that impetus of breeze, might start by improving the situation before the more unsettled conditions spread in.

 

This happens in winter - initial clear conditions are replaced by cloud in the absence of a breeze.

Yes, more than a sense of dejavu about ECM t96 onwards. I would imagine it isn't so simple as to say slack easterly=cloud, though to the east of London you are obviously in a less favoured place.

Seeing a very undefined low at T240 tells me that any notion of a definite breakdown is far off. Hurricane Bertha apart, the Scandi High seems to be the ruling force of the moment, and countless model attempts to sink it since the start of summer have failed, so I'd caution against calls for a breakdown on such a weak attack

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Posted
  • Location: Camborne
  • Location: Camborne

Looking at the 8-14 anomalies for any sign of a change of pattern. Perhaps there is. They are in reasonable  agreement with the high still to the NE and a ridge around the UK but the ridge in the west Atlantic has declined allowing the jet to push further south and a more zonal flow. Obviously surface synoptics are in Gypsy Rose Lee territory but it could well be that the HP to the NE will slip further east and the Azores/Bermuda high mid Atlantic pushed further south setting up an intrusion by the Atlantic. Equally if the AZ/B high doesn't slip south and our resident low near Spain continues to influence then the status quo, or something akin to it, could remain.

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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.

The GFS this morning shows an unsettled/cooler pm flow pushing in from the N/W  just after mid-Month.

 

gfsnh-0-252.png?0gfsnh-0-276.png?0gfsnh-1-288.png?0

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

UKMO continues to show high pressure dominating, so staying dry with variable cloud cover

 

U96-21UK.GIF?08-07U120-21UK.GIF?08-07U144-21UK.GIF?08-07

 

Temperatures should be ranging from the mid teens in the north to low 20's in the south, but feeling warm anywhere if you have some sunshine

 

UW96-7.GIF?08-07UW120-7.GIF?08-07UW144-7.GIF?08-07

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

Ensemble means at D10: pretty much identical to four/five days ago. ECM, again, is hinting at an Atlantic breakthrough but with little conviction, though a corridor is open between the Scandi High and the Mid-Atlantic High for something less settled to move in from the North-West. GFS, again, favours more settled weather:

EDM1-240.GIF?08-12

gens-21-1-240.png?0

Though GFS Op threw up a reasonably deep depression just after D10, as PM points out, there are very few ensemble members that bring low pressure across mainland UK by D10, probably somewhere between 10% and 20%.

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=240

So I can't really see much rain on the horizon, which is not today's Met Office line, which suggests more changeable next week. Perhaps they are expecting the low in central Europe to drift back towards the UK in the easterly flow - a few ens members of the ECMWF show how this might develop (this is T120, can't see further out):

http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2014081700!!/

but you'd still have to say this appears to be the less likely option. The same thing happened last week - the METO forecasted more unsettled this week , which it was clear from the models was far from a done deal, and lo and behold we have settled week ahead. I wonder if the Met Office 6-15 day forecast sometimes runs into trouble because it tries to be too precise? It never seems to allow for too much possibility in the way that its 16-30 day forecast does. Looking at the models this morning, you would have to conclude that next week (D7-D10 anyway) is looking more likely to be settled than unsettled, so I wonder if the same thing is going to happen again.

I know some people hate it when the METO get criticised here - and sometimes I hate it too - but please bear in mind I am only stating a fact - they forecasted unsettled this week, the models we see never forecasted a breakdown with certainty - and it was the models we see, particularly GFS, that were correct from quite a way out. I'm not criticising their forecasting ability, but rather the way they present D6-D15 with so much certainty sometimes.

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Posted
  • Location: Orleton, 6 miles south of Ludlow
  • Location: Orleton, 6 miles south of Ludlow

Looking dry to at least the middle of September for both south and northern England.

http://www.wetterzentrale.de/pics/MT8_Manchester_ens.png

http://www.wetterzentrale.de/pics/MT8_London_ens.png

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