Model output discussion - is the beast awakening?

[jacke]

2 hours ago, Don said:

Sorry Crewe but if we don't get a cold February, I'm going to have to insist you eat that sock! 

Your such a happy lad Crewe

[danthetan]

1 minute ago, Stu_London said:

If referring to me you have misinterpreted the spirit of my musings. I don't suffer an angst over weather, unless it affects my ability to carry my daily business, then it becomes annoying. Im a severe weather enthusiast who has long since excepted that the weather will do what it will do. Any edginess in the posts is humour or irony 

no not you.

[Stu_London]

1 minute ago, danthetan said:

no not you.

ok happy days

I thought maybe my south of M4 rants were getting a bit whingy

happy to clear that up

[Don]

8 minutes ago, Stu_London said:

If referring to me you have misinterpreted the spirit of my musings. I don't suffer an angst over weather, unless it affects my ability to carry my daily business, then it becomes annoying. Im a severe weather enthusiast who has long since excepted that the weather will do what it will do. Any edginess in the posts is humour or irony 

I think he may have been referring to me.  If so, incorrect also, no tantrums from me regarding weather, although I like others show frustration at times but at other times my comments are purely tongue in cheek!

Anyway's time to hit the sack and look forward to more fun and games tomorrow! 

Edited January 31, 2021 by Don

[Stu_London]

3 minutes ago, Don said:

I think he may have been referring to me.  If so, incorrect also, no tantrums from we regarding weather, although I like others show frustration at times but at other times my comments are purely tongue in cheek!

cool - lets let the weather do as it does.

Lets hope for the para and expect the ECM - that way expectations do not get too elevated. And lets forgot the golden rule with UK cold spells, anything that can go wrong will go wrong - ridiculous lack of severe weather for a country positioned on our latitude

Edited January 31, 2021 by Stu_London

[danthetan]

1 minute ago, Stu_London said:

ok happy days

I thought maybe my south of M4 rants were getting a bit whingy

happy to clear that up

didn't even see them haha. no clue what your on about. all the best though. 

[Stu_London]

3 minutes ago, danthetan said:

didn't even see them haha. no clue what your on about. all the best though. 

you too - lets hope the weather delivers what you hope for (might be bbq weather for all I know)

Edited January 31, 2021 by Stu_London

[danthetan]

Just now, Stu_London said:

you too - lets hope the weather delivers what you hope for (might be bbq weather for all I know)

definitely not bbq. more clarity on the easterly though long way to go solve this riddle.

[Mike Poole]

3 minutes ago, Stu_London said:

Thanks Mike for a very concise explanation.

So that is positive - but does it still have the same weakness as the existing GFS - there is a very specific route to what would be a monumental cold spell (probably not that welcome to the country as a whole right now). It just looked way too clean for me - not many disruptive features like shortwaves - our weather tends to messier than that

That’s a big question. What is wrong with the GFS?  As I’ve some of my beer left, and nothing else to do, I will try to answer.  

The GFS has had several upgrades recently in terms of model resolution, vertical or horizontal, and none seem to have given it a gain over the GEM, let alone the UKMO and ECM.  

I don’t think it is the model, I think it is the procedure / algorithm for calculating the position at T0.  Data is collected at various times and in various places, and the model needs to get the best possible understanding of the whole atmosphere at T0 for the forecast calculation. And that is a very difficult mathematical problem, called the ‘inverse problem’, determining what T0 conditions would have best come from the observed data at different times.  The UKMO and ECM tackle this using state of the art maths (called 4DVar) but GFS fudges it a bit, so it doesn’t do it as well.  It is a chaotic system, so if your initial data is a bit rubbish, no amount of extra model resolution will sort that.

Ironically, this might be the reason why ECM is wobbling a bit.  We’re lacking flight data at the moment, which is time varying, the kind of thing the 4DVar is designed to cope with - data at different times, it may be that the current data available to to model initiation doesn’t benefit the ECM as much. 

Just my take on it, of course, and happy to be corrected.

[Allseasons-Si]

Guys,...lets just wait and see what happens over the coming days,there is a lot going on next week in terms of how far this low drops S/SE

this is not a guarantee and this is a pivotal point to getting that easterly that has been showing in the models but we need 100% agreement on this

we have been lucky so far this winter and many have had snowfall settling and plenty of frosts too(lost count how many) so this winter has been better than most recently,sledging in the south in London park,snowball fights in Leeds and they pay the price from COVID rules,...that sucks for having a good time

sods law that we get a really big dumping but we can only enjoy it IMBY.

 

[Stu_London]

Just now, danthetan said:

definitely not bbq. more clarity on the easterly though long way to go solve this riddle.

yes the para has thrown a spanner in the works delivering what I think might be the most brutal long lasting cold spell to most of us that I have ever seen in 22 years of model watching, when the trend was for a more 'surface cold' outcome from the other models, although the GEFS 18Z swung back a little that way

[danthetan]

1 minute ago, Stu_London said:

yes the para has thrown a spanner in the works delivering what I think might be the most brutal long lasting cold spell to most of us that I have ever seen in 22 years of model watching, when the trend was for a more 'surface cold' outcome from the other models, although the GEFS 18Z swung back a little that way

How the low makes its exit is key here looking beyond that well............. lotto numbers?

[Stu_London]

7 minutes ago, Mike Poole said:

That’s a big question. What is wrong with the GFS?  As I’ve some of my beer left, and nothing else to do, I will try to answer.  

The GFS has had several upgrades recently in terms of model resolution, vertical or horizontal, and none seem to have given it a gain over the GEM, let alone the UKMO and ECM.  

I don’t think it is the model, I think it is the procedure / algorithm for calculating the position at T0.  Data is collected at various times and in various places, and the model needs to get the best possible understanding of the whole atmosphere at T0 for the forecast calculation. And that is a very difficult mathematical problem, called the ‘inverse problem’, determining what T0 conditions would have best come from the observed data at different times.  The UKMO and ECM tackle this using state of the art maths (called 4DVar) but GFS fudges it a bit, so it doesn’t do it as well.  It is a chaotic system, so if your initial data is a bit rubbish, no amount of extra model resolution will sort that.

Ironically, this might be the reason why ECM is wobbling a bit.  We’re lacking flight data at the moment, which is time varying, the kind of thing the 4DVar is designed to cope with - data at different times, it may be that the current data available to to model initiation doesn’t benefit the ECM as much. 

Just my take on it, of course, and happy to be corrected.

Thank you Mike - that's very informative and you clearly have great knowledge on the subject.

I think I would still like a win on its record to show that it can lead in modelling. 

Bit like a stallion at stud - could have run well in one of the classics without winning but did at least win a maiden race or something so you know it can win.

[Stu_London]

3 minutes ago, danthetan said:

How the low makes its exit is key here looking beyond that well............. lotto numbers?

it is key as is the predisposition of models to bring in new features as it reacts to updated current conditions. I think an easterly is probably odds on now, but you couldn't rule out a complete collapse. Still 3 complicated weather events to get through, all of which could be game changers for better or worse.

[Mike Poole]

5 minutes ago, Stu_London said:

Thank you Mike - that's very informative and you clearly have great knowledge on the subject.

I think I would still like a win on its record to show that it can lead in modelling. 

Bit like a stallion at stud - could have run well in one of the classics without winning but did at least win a maiden race or something so you know it can win.

Your question was originally about the GFS // i think?  Well the same T0 data initialisation issues apply, no change there.  But the vertical resolution increase would likely give it an advantage during a SSW as that’s where the important things are occurring.  So, at the moment, I would definitely rate the // over the GFS op run.  But come spring and summer, I expect it will be equally good/bad as the op as the strat doesn’t impact our weather then.  

[danthetan]

10 minutes ago, Stu_London said:

it is key as is the predisposition of models to bring in new features as it reacts to updated current conditions. I think an easterly is probably odds on now, but you couldn't rule out a complete collapse. Still 3 complicated weather events to get through, all of which could be game changers for better or worse.

concentrate on how that behaves will determine the outcome its as simple as that. knife edge stuff. easterly is the form horse I don't disagree its in what form.  SE crap, E good , NE jackpot basically clear as mud. 

[Kentspur]

31 minutes ago, danthetan said:

concentrate on how that behaves will determine the outcome its as simple as that. knife edge stuff. easterly is the form horse I don't disagree its in what form.  SE crap, E good , NE jackpot basically clear as mud. 

Seeing as I'm on a very quiet night shift I thought I'd take the time to write a longer post than usual as I have a spare 4hours! 

 

I would argue it depends on your location on a micro/regional scale with the exact wind vectors for instance for places that haven't seen snow such as my area in NW Kent and the same for S Essex parts of South and East London and East/North Surrey and parts of inland Sussex aswell, an ENE is by far the best wind flow creating the Thames streamers for us, a ESE is great for areas such as Devon and other channel counties plus parts of East Anglia/NE, a NNEly great for the far East of Kent/Norfolk as is a straight NEly.

A straight Easterly depending on strength of the flow is in my opinion the best general flow for most regions but especially Eastern areas from Aberdeen through the NE, the humber down to Essex and Kent. For Western regions a straight Easterly crosses less land before reaching those Western parts of the country including Wales and the West Midlands as the Beast from the east showed us.with a very strong easterly flow at times enabling not just Eastern areas to get in on the act. I'm pretty sure Wales and parts of the West Midlands had a lot more snow than I saw in NW Kent- we had far less in 2018 than in November- Dec 2010 Which was def more ENE than E for much of the time.

Its a real catch 22 on one hand you could have for instance a long fetch  NEly originating from further north from say Murmansk but on the other hand its also got to combat the warming effects of the SSTs over the North Sea whereas a "drier" ESEly flow may bring colder continental air but less precip for Southeastern areas for instance with a shorter sea track. Both wind directions for my part of the country aren't normally great for producing snowfalls but are better for other regions that have seen very little so far as I mentioned. However I remember 21st January 2013 an area of snow moved up from France/Belgium on a ESE flow giving us 5inches of snow by the Thames more elsewhere, that's the one exception I remember.

As you say the models are playing about with different wind vectors and it will be interesting to see what the consensus is in the coming days, it would be nice to have total UK snow cover as I said 2010 for me was amazing in that 95% of the country was under a blanket of white and its this id like to see challenged again so everyone's a winner in "Great" Britain

Shhhh! Don't tell Sturgeon I said that, or Mary Queen of Scots as I like to call her

Edited January 31, 2021 by Kentspur

[A Frayed Knot]

Took me over an hour to read through all that tat and still ain't got a clue what's going on with the majority of some (kids) in here. 

Its like Gifyleegoop in here. Nuff of the gifs and This and that ECM for frogs sake. Forget about if its going to Snow in Wales today or the Midlands and the likes of London are going to miss out. Who gives a hoot about that. Let's get the cold in and go from there... We are on a cusp of incoming cold and a rinse and repeat of 2010 lovely hoarse Frost. Give me that everyday and freezing rain. The tingling in the trees are so beautiful. Also please feed the birds and squirrels and other habitats in you are if it freezes over. Goodnight. 

[Andypvfc]

24 minutes ago, Kentspur said:

Seeing as I'm on a very quiet night shift I thought I'd take the time to write a longer post than usual as I have a spare 4hours! 

 

I would argue it depends on your location on a micro/regional scale with the exact wind vectors for instance for places that haven't seen snow such as my area in NW Kent and the same for S Essex parts of South and East London and East/North Surrey and parts of inland Sussex aswell, an ENE is by far the best wind flow creating the Thames streamers for us, a ESE is great for areas such as Devon and other channel counties plus parts of East Anglia/NE, a NNEly great for the far East of Kent/Norfolk as is a straight NEly.

A straight Easterly depending on strength of the flow is in my opinion the best general flow for most regions but especially Eastern areas from Aberdeen through the NE, the humber down to Essex and Kent. For Western regions a straight Easterly crosses less land before reaching those Western parts of the country including Wales and the West Midlands as the Beast from the east showed us.with a very strong easterly flow at times enabling not just Eastern areas to get in on the act. I'm pretty sure Wales and parts of the West Midlands had a lot more snow than I saw in NW Kent- we had far less in 2018 than in November- Dec 2010 Which was def more ENE than E for much of the time.

Its a real catch 22 on one hand you could have for instance a long fetch  NEly originating from further north from say Murmansk but on the other hand its also got to combat the warming effects of the SSTs over the North Sea whereas a "drier" ESEly flow may bring colder continental air but less precip for Southeastern areas for instance with a shorter sea track. Both wind directions for my part of the country aren't normally great for producing snowfalls but are better for other regions that have seen very little so far as I mentioned. However I remember 21st January 2013 an area of snow moved up from France/Belgium on a ESE flow giving us 5inches of snow by the Thames more elsewhere, that's the one exception I remember.

As you say the models are playing about with different wind vectors and it will be interesting to see what the consensus is in the coming days, it would be nice to have total UK snow cover as I said 2010 for me was amazing in that 95% of the country was under a blanket of white and its this id like to see challenged again so everyone's a winner in "Great" Britain

Shhhh! Don't tell Sturgeon I said that, or Mary Queen of Scots as I like to call her

Tbh even in 2010 and more so in 2018, we on the North Staffs / South Cheshire Border (Far North of Stoke on Trent had very little Snow mate. 

With the big Snow events as with Storm Emma with the last Beast from the East, we were just too far North. Whereas when it comes from the North, we are just too far South as it stops at Manchester . 

Yeah in fairness we did OK just after this Christmas, but even then nothing more than around 4inches. 

Oh for a good event like Feb 1996 lol 

[Kentspur]

26 minutes ago, Andypvfc said:

Tbh even in 2010 and more so in 2018, we on the North Staffs / South Cheshire Border (Far North of Stoke on Trent had very little Snow mate. 

With the big Snow events as with Storm Emma with the last Beast from the East, we were just too far North. Whereas when it comes from the North, we are just too far South as it stops at Manchester . 

Yeah in fairness we did OK just after this Christmas, but even then nothing more than around 4inches. 

Oh for a good event like Feb 1996 lol 

Only 4 inches? That's more than we get most winters id happily take that once every winter! Feb 1996 don't remember all that way apart from it was cold not sure there was much snow down here but I remember March 96 going sledging funny enough which sticks out more in my mind something tells me it was around 8th March

[Stu_London]

1996 was jackall for the south east - lots more action north and west

[Mr snowman 2018]

BBC weather for the week ahead  update is very poor just saying hill snow only now I think that will be the outcome 

[Stu_London]

Just now, Stu_London said:

1996 was jackall for the south east - lots more action north and west

5th Feb 1996 the famous half metre of snow event at Eskdalemuir - think the front stalled and it just keep snowing and snowing

[Andypvfc]

2 minutes ago, Kentspur said:

Only 4 inches? That's more than we get most winters id happily take that once every winter! Feb 1996 don't remember all that way apart from it was cold not sure there was much snow down here but I remember March 96 going sledging funny enough which sticks out more in my mind something tells me it was around 8th March

Lol. Yes Matt from Stoke very often makes me smile how he gets excited over a few cm, but then he orginates from down South and very often says up here is like Narnia compared to what he's used to. Lol.

Perhaps as a kid growing up in 70s and remembering massive Snowdrifts through the 80s spoilt us up here. Unless being only 5ft 4, they just seemed deeper than they actually were .

As Matt says nowadays Stoke tends to have more small falls, but more often. Whereas North or South prob gets the bigger events off incoming fronts, that just don't make it this far lol

[Stu_London]

7 minutes ago, Mr snowman 2018 said:

BBC weather for the week ahead  update is very poor just saying hill snow only now I think that will be the outcome 

I think Meteo Group are still working on yesterdays ECM. Both runs poor (compared to the other output).

Not saying it couldn't be correct but likely to change as lots of flip flopping by the ECM. The 12z was a small step closer to a colder outlook - who knows what the 00z runs will bring, except to say the 18z models did trend a little bit colder.

Besides most of the week will be relatively mild apart from the far north as the cold will be working its way south from Thursday onwards at the earliest

 

 

Edited January 31, 2021 by Stu_London