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Model Output Discussion 4th Dec.2013-12z onwards.


phil nw.

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Posted
  • Location: Epsom, Surrey, 100 Meters above sea level
  • Weather Preferences: Anything Extreme
  • Location: Epsom, Surrey, 100 Meters above sea level

3 weeks of the frist month of winter remains and as much as I like to be a glass half full kinda guy I'm really struggling to find any way out of this current set up.

 

Each time we get a tiny window of opportunity and High pressure looses it's influence on te charts. another one rolls in to take it's place.

 

It's like autumn but reversed...I.E instead of the UK being battered by a series of low pressure systems, it appears that the UK is being bombarded by a series of High pressure systems rolling in off the Atlantic, setting up shop to the South East , deciding to go somewhere else and then it's replaced by another.

 

Yes things do look to become quite mobile in the North but for the sake of argument let's look at the opening GFS frame

 

Posted Image

 

And now the final frame

Posted Image

 

There's obviously a fair amount going on in between but the overal pattern hasn't changed , hence my initial statment that I really cannot see a way out of this, even on the final frame an Azores high is ready waiting in the wings ready to pounce and so the blandness of the first month of Winter 2013/2014 continues tonight :-(

 

Surely something has to give soon ??

On a side note it's been remarkably dry IMBY since June, asides from a 2 week period between mid and late October

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Posted
  • Location: winscombe north somerset
  • Weather Preferences: action weather
  • Location: winscombe north somerset

Ian practically wrote off chances of a white Christmas for the BBC West region on this evening's forecast, while stating that a change to unsettled conditions with wind and rain were very likely from the end of this week through until Christmas.

Well i never saw Ian on telly tonight ,but it totally surprises me that he would write OFF snow at Christmas at this range ,a full two weeks and a day in the future .of course he as the knowledge of charts and info from the met office and is quite rightly in the right to put his thoughts across but at this range i feel that is one hell of a gamble .im pretty sure looking at the charts that we have the Potential for some interesting weather on the run up to Christmas .Posted Image

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Posted
  • Location: South Essex
  • Location: South Essex

The long range models including the ECM 32 appear to be utterly rubbish tbh. Ok, we are not looking at a big cold spell, but 48 hours ago we had complete model agreement on a high pressure dominated scenario for the next 3 weeks. It looked like no rain would fall over much of the country before Christmas etc etc. By this morning everything was screaming zonality.

Personally I'm a lot happier with the charts tonight. They are far from ideal but it's better than what appeared to be a nailed on Bartlett and for that we can all be grateful.

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Posted
  • Location: Ribble Valley
  • Location: Ribble Valley

Well i never saw Ian on telly tonight ,but it totally surprises me that he would write OFF snow at Christmas at this range ,a full two weeks and a day in the future .of course he as the knowledge of charts and info from the met office and is quite rightly in the right to put his thoughts across but at this range i feel that is one hell of a gamble .im pretty sure looking at the charts that we have the Potential for some interesting weather on the run up to Christmas .Posted Image

Indeed, with an active Atlantic and returning PM air in the mix any talk of  writing off the chances of a white xmas for some is a tad premature for sure.

Edited by Sceptical Inquirer
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Posted
  • Location: Langley Waterside, Beckenham
  • Location: Langley Waterside, Beckenham

I think we ought to play another game in here, see how long a forum user can post without mentioning the word MILD or COLD in their posts. Posted Image I've already ruled myself out and besides, I'm usually only here lurking in the background but of late, I have attempted to add my tuppence to the ongoing debates. So here goes my analysis of pretty much all of today's afternoon NWP output and I will most likely use those aforementioned words again.

 

Whilst it may have been reasonably mild today, Posted Image  in fact well above especially for parts of Scotland and perhaps Ireland (5c to 8c Temp range considered average for those regions at this time of year), this general theme is largely being removed from all outputs.

 

By the 12th into the 13th December, as anticipated by me a week ago, a change to a stronger Jet dominated active weather regime will have begun to impact  the far North and Northwest of Britain and perhaps with it a lot more rain. Posted Image  Temperatures still up above average but several degrees down on todays with in this region. Further South and away from the above region, things could get milder still, dependant on sunshine levels and maybe a 11c or 12c isn't out of the realms of possibility. Where isolated fog and low cloud continues to plague prone areas, it will feel far from mild, potentially cold  and maybe average at best. (7c to 9c more usual down South).

 

Come the 14th December (t+96 currently) and thereafter into the unreliable (which is can best be judged by studying where scatter begins on your favoured ensembles runs) all current NWP outputs favour more average Temperatures. These conditions along with bands of rainfall are increasingly showing up of late with a higher percentage favouring colder PM interludes than those from warmer TM airmasses. All precipitation events suggest rain but giving timing nuances snow may become increasingly apparent as time goes by, those favoured by elevation more pleased with this and we'd best forget those of us in low lying areas away from most of England. By the 17th December (t+168 currently), a transient ridge of HP is attempting to return to our shores once again on some outputs, at least out to our SW approaches, but there is not a strong signal for this to happen just now so I personally won' be buying this yet. Posted Image

 

That for me is broadly speaking the next seven days covered and hopefully by the early part of next week will see if those PM incursions can continue to get a look in.

Post gtltw  Good to see a post dealing with the here n  a bit later rather than Crissy eve and beyond and having a personal wild guess like some Appreciated.

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Posted
  • Location: Oyne Aberdeenshire 120m asl
  • Weather Preferences: SNAW
  • Location: Oyne Aberdeenshire 120m asl

Champions League game in Istanbul abandoned due to SNOW......didnt any model show this weather happening ten days ago?? maybe it a sign for xmas.. Turkey & Snow

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Posted
  • Location: uxbridge middlesex(- also Bampton oxfordshire
  • Weather Preferences: blizzard conditions. ice days
  • Location: uxbridge middlesex(- also Bampton oxfordshire

A bit controversial post to Gotta. The pro's are no better at creating a mid to long term forecast than the part timers on here - All people are doing is reading what the consensus model shows. They are not forecasts, they are data interpretation & statistical probabilities based on information.I appreciate this is VERY broadbrush, but for all intensive purposes its not that hard- Theres plenty on here that could ( &do) do that day in day out- Gibby does for instance. Pro forecasters will earn there money & short range forecasts up to 96 hours- where the ability to draw / create fax charts which show frontal zones etc etc becomes superior to the weekend hobbyist- of course its probably a lot easier these days to present a forecast V Pre computer era- however its still a high level science.. If you look at the information that's available AFTER the medium term you haveECM, UKMO4?, Decider models & a few other bits & bobs - Lets say for arguments sake we are 12 days away from a Scandi high & a strong easterly- I would 100% GUARENTEE that even at day 12 the consensus would be against that outcome as the model bias will always overrun the westerly pattern & flatten the blocking pattern- How many times have we seen an Easterly 'appear' from a Scandi high where the high suddenly appears to 'raise' up as T-0 approaches- its because the models are seeing a slower jet & greater amplification.The GFS & ECM ensemble mean will never pick up a 'ridge' as fast as the operational as the resolution isn't a great. Where the forecasters will be wrong then is clearly when the models are wrong & or the ensemble suites are wrong, so in the MEANs forecasting the height anomaly at day 8-10 is fairly straight forwards-However whats hard is to forecast when the means are wrong- be it to fast/ to slow etc- I try to do this & yes I don't always call it right-  Look at the call for this week- Scandi heights YES- Scandi High- NO- so longwave pattern correct, shortwave pattern NO. Also, this isn't a dig @ Matt but whatever method you use - you live by the sword & die by the sword- the ECM DET 32 I would bet my house on the next update will show a lot of scandi heights, but not many will go onto a full blown Easterly.However its to early to dismiss it & way to early to say its wishful thinking-  that's the SAFE bet. What I like at least with Ian is his wording & breakdown does well to cover the plausible outcomes- but of course going with the favoured ensemble option.... Well luckily enough we are not bound by any contracts to anyone- just putting our own spin on it. -  IF we can get to a position where we can forecast an outcome which verifies better than the smoothed ensembles this will be better than just brush stroking the canvas with the 500 anomalies. Doing this will take time but Id rather do that than just read the model script as many do on here- pro & hobbyist alike......... S A PS- whenever there are Scandi heights the UK is nearly always on the cusp- right at the end of line as it were- That means small adjustments poleward of the high will often have huge effects on the temps observed over the UK- SW wind 15c SE Wind 3c -The ECM tonight @ 192 wouldn't take much to show a very cold surface feed.........

..a fantastic post SM, and how one interpret evolutionary/solution, is just that...single interpret is why meteorological is of such intrest,for both what it is and indeed how individuals evaluate possible outcomes!! As for as we stand,even with a science BG, it complex....to say the least....(look out for output flip)!!!
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Posted
  • Location: Evesham/ Tewkesbury
  • Weather Preferences: Enjoy the weather, you can't take it with you 😎
  • Location: Evesham/ Tewkesbury

Indeed, with an active Atlantic and returning PM air in the mix any talk of  writing off the chances of a white xmas for some is a tad premature for sure.

Indeed, this was what I was talking about yesterday, you can really have a one day snow storm out of this scenario, not long term cold , but some surprising snowfall at least....Posted Image Posted Image Posted Image

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Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

A bit controversial post to Gotta.

 

 

 

I haven't got time to read through your input right now Steve and will most certainly do so in the morning. Posted Image  However, just to clarify by choice of the word "professional", I simply meant the seasoned model watchers and those working whom work or have worked for Meteorological companies and suchlike. For the record Steve, you are a seasoned model interpretator yourself and no I'm not on here just to kiss your sausage shaped high. Posted Image Back to model discussion you lot as I need a lie down, more fun and games in the morning I suspect and hopefully a few more baby steps towards something more seasonal into FI and beyond. Posted Image

Edited by gottolovethisweather
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Posted
  • Location: Locksbottom, NW Kent 92m asl(310ft)
  • Weather Preferences: Warm summers but not too hot and colder winters with frost and snow
  • Location: Locksbottom, NW Kent 92m asl(310ft)

Sorry to ask this but am still learning from models etc but what are chances of High building over Scandinavia at T240 from latest ECM run?Could one of the experts on here just give me a few pointers? My understanding is we are still in a too mobile Westerly pattern for High to get established and with Vortex not splitting over to the East to Siberia we are not getting much help here. Probably got this all wrong so would appreciate a bit of help explaining where say T264 might be(sorry I tried to paste T240 but my limited PC skills wouldn't allow it!!).Many Thanks

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Posted
  • Location: st albans
  • Location: st albans

Champions League game in Istanbul abandoned due to SNOW......didnt any model show this weather happening ten days ago?? maybe it a sign for xmas.. Turkey & Snow

All models were showing this 10 days ago. A common consequence of a sceuro block is wintry conditions in se europe.
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Posted
  • Location: Dousland, South Dartmoor 205 m/asl
  • Weather Preferences: The fabled channel low
  • Location: Dousland, South Dartmoor 205 m/asl

Ian would of been talking about the points West area only though

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Posted
  • Location: Near Keele, North Staffs
  • Location: Near Keele, North Staffs

Champions League game in Istanbul abandoned due to SNOW......didnt any model show this weather happening ten days ago?? maybe it a sign for xmas.. Turkey & Snow

 

Yes, the models did show this cold plunge into Turkey/Greece.

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Posted
  • Location: Locksbottom, NW Kent 92m asl(310ft)
  • Weather Preferences: Warm summers but not too hot and colder winters with frost and snow
  • Location: Locksbottom, NW Kent 92m asl(310ft)

A difficult one but not perfect- the angle of the jet is still NE facing-

 

Ive annotated the red as the angle- is called a positive tilt.

The black is the angle ideally we want to see- or at least Northward -

 

Posted ImageECH1-240.jpg

 

s

Thanks Steve-Very much appreciated.

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

Champions League game in Istanbul abandoned due to SNOW......didnt any model show this weather happening ten days ago?? maybe it a sign for xmas.. Turkey & Snow

 

And compared to the snow at the American football game on Sunday this was nothing

 

Posted Image

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Posted
  • Location: Glasgow, Scotland (Charing Cross, 40m asl)
  • Weather Preferences: cold and snowy in winter, a good mix of weather the rest of the time
  • Location: Glasgow, Scotland (Charing Cross, 40m asl)

I think as a general rule having high confidence in any model solution post +168 and certainly post +240 is rather foolhardy - while we may speculate as to the outcome and while we can give a reasonable estimate on the probability of an outcome depending on the degree of support from the longer range EC ensembles, MOGREPS, the EC 32 dayer etc. we always have to be wary of chaos theory even in what may seem like a relatively straightforward progression with a fairly large margin for error for the general weather pattern i.e. the current train of SW/Westerlies fuelled by a strong Greenland centred tropospheric vortex, a cold stratospheric vortex and a euro high. We can have somewhat higher confidence than normal in the general weather type for the British Isles for say D6-D10 than normal, given good model agreement for a mobile westerly pattern (albeit with varying degrees of amplification and Pm airmasses into Scotland depending on your model of choice) but even today we've seen one or two charts in FI which hint at the possibility of something more interesting via troughing digging that bit further south, encouraging ridging of heights northwards into Scandinavia.

While I think a full blown easterly is very much an outside bet at this stage I wouldn't be surprised to see more cold solutions in the coming days as the models toy with the next phase of our winter, but equally the outlook remains pretty unspectacular for sustained HLB in general and, for the foreseeable at least, any cold is likely to be squeezed out of favourably positioned mid latitude heights rather than stonking great Greenie highs.

 

edit: I started typing before reading Ian's post so the use of foolhardy in both is purely coincidental, honestPosted Image

Edited by LomondSnowstorm
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Posted
  • Location: Ribble Valley
  • Location: Ribble Valley

I can only vouch for Matt's post, from a wholly neutral perspective re mild/cold aficianados. Ultimately, he's reflecting exactly what today's EC32 output shows - indeed, examination of all 51 of the individual members right through to the end of it's run show scant sign of cold blocks in the de facto sense. Unsurprisingly, the 2m temp anomalies range from mild to eventually a blander average signal by early Jan; similarly, examination of, e.g., Reading ENS plumes show 850's decreasing gradually (as do 500mb heights, incidentally) but never with many members dropping below circa -5C.Ultimately, EC32 (and DECIDER) remains the best tool we have to offer some (even vague) approach to the period going forward, short of speculation and what-if's beyond the realms of it or other models. Consequently, it remains a key product used by UKMO and many other national Met agencies. Now, we all know how things can change (and often do), so in all honesty, I'd hope that the current output is not used as some hickory bat with which to beat-up others on the forum (or oneself) if favouring cold or mild. What will happen, will happen.Clearly, the form horse 'broad-brush' for now (as I outlined for the non model-watchers on BBC Points West) is a continuation of a broadly SW flow, hence often mild (in comparative terms); periodically wetter/windier and also (importantly), as I stressed, periodically chillier given scope for occasional bouts of polar maritime or returning polar maritime flow. However, as I also stressed, no output currently offers an plausible sign of deeper cold incursions; nor (as Matt explains) does EC32 offer any plausible sign of colder blocking patterns within it's present output timeline.Let me be clear: no-one (certainly not at Met O) is ruling in or out any manner of eventual outcome into Jan/Feb. However, for now at least, we can only run with what is in front of our eyes and on our PC screens; and to describe such output without bias or 'hopecast' tendency. The latter is not what we are paid to do but is exactly where forums such as this play a role in debate.Hope the coldies find the 'cherished land' eventually in the winter charts!BestIan

But those EC32 chop and change far too frequently to have any sort of confidence in them, granted you can only post what the models show but these show something different every week. Edited by Sceptical Inquirer
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Posted
  • Location: Redhill, Surrey
  • Weather Preferences: Southerly tracking LPs, heavy snow. Also 25c and calm
  • Location: Redhill, Surrey

Looking at the GFS I think its looking like it might have the general idea, I hope so as this HP to our ESE has been more influential than expected keeping the Atlantic at bay.  I think once the push comes we'll get some complicated set ups with sub lows swinging in on southerly track with that block to our ESE/E being never far away and may hold up weather fronts over us.  Atlantic to control but far from benign ... this is a complicated set up

 

Posted Image

 

far from boring imo

 

 

BFTP

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

The situation is hopeless for any cold. I am amazed how people can delude themselves into 'seeing' potential wintry scenarios develpoing in an essentially locked in mild nightmare..

The natural forcings are so strongly biased towards mild zonal dominance as to be virtually unassailable for at least 10 days if not more.

 

Wretched mean anomally chart

 

Posted Image

 

Wretched cpc chart

 

Posted Image

 

Very zonal ENS

Posted Image

 

Not a pretty sight and not likely to improve for a long while. Posted ImagePosted Image

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Posted
  • Location: Ribble Valley
  • Location: Ribble Valley

Looking at the GFS I think its looking like it might have the general idea, I hope so as this HP to our ESE has been more influential than expected keeping the Atlantic at bay.  I think once the push comes we'll get some complicated set ups with sub lows swinging in on southerly track with that block to our ESE/E being never far away and may hold up weather fronts over us.  Atlantic to control but far from benign ... this is a complicated set up

 

Posted Image

 

far from boring imo

 

 

BFTP

Good to see you back posting Fred, I hope your father is back on the road to recovery now.
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