Model Output Discussion - cold spell to end Autumn

[Frosty.]

3 minutes ago, Johnp said:

I must be looking at another GFS run to everybody else?

Looks cold and potentially snowy to me.

To be fair, I've already mentioned that???☺

[West is Best]

22 minutes ago, SizzlingHeat said:

So another couple of cold days followed by a milder weekend and then a mild week followed by perhaps a stormy beginning to next weekend. Not much cold showing up now anymore.

Someone called 'Sizzling Heat' says he, or she, sees the GFS 12z giving 'a mild week' with 'not much cold showing up now anymore.'

Hmmm. There's always this sort of trolling and you may well prove right. Statistically and historically you probably will be.

But, for the avoidance of doubt, that 12z GFS is not a 'mild' run. In fact, synoptically it's a storming run bringing biting north-west through north-easterly winds which would feel bitterly cold: the wind chill off that would be off the scale.

I mean, seriously, you are having a laugh ... right? Look. No, truly, look:

 

I love the synoptics of this. And I'll take a fired jet if it shifts things too. 90% Sizzler will be right that the reload will go mild. But I'll take these odds because one day, boy, are you mild-spectacled folk going to be in for a rude shock. The 10% roll will happen.

[winterof79]

6 minutes ago, West is Best said:

Someone called 'Sizzling Heat' says he, or she, sees the GFS 12z giving 'a mild week' with 'not much cold showing up now anymore.'

Hmmm. There's always this sort of trolling and you may well prove right. Statistically and historically you probably will be.

But, for the avoidance of doubt, that 12z GFS is not a 'mild' run. In fact, synoptically it's a storming run bringing biting north-west through north-easterly winds which would feel bitterly cold: the wind chill off that would be off the scale.

I mean, seriously, you are having a laugh ... right? Look. No, truly, look:

 

I love the synoptics of this. And I'll take a fired jet if it shifts things too. 90% Sizzler will be right that the reload will go mild. But I'll take these odds because one day, boy, are you mild-spectacled folk going to be in for a rude shock. The 10% roll will happen.

Well put WIB and ties in with this pm's METO update through December.

[nick sussex]

Not bad and not great. Its neither a Little Chef special or a Michelin starred dinner but with some tweeks could be a good night out!

At least we have model agreement which has been lacking so the shortwave energy splits so that's one hurdle the outputs get over.

The GFS in its later output keeps the positive PNA so that's good, if the troughing in the east USA keeps the main PV stuck in Canada then the energy coming off the eastern USA could track more ese and theres still a chance we'll see that track favourably to engage colder air near the UK.

Overall given what could have happened the outputs so far have enough scope to improve without needing a dose of fiction or a Hollywood writing team.

The main thing is the shortwave energy splits and the shortwave low getting east of the UK with the ridge building in from the nw, that's still not a given so I think before looking too far ahead we need that in the T96hrs timeframe.

[markw2680]

8 minutes ago, West is Best said:

Someone called 'Sizzling Heat' says he, or she, sees the GFS 12z giving 'a mild week' with 'not much cold showing up now anymore.'

Hmmm. There's always this sort of trolling and you may well prove right. Statistically and historically you probably will be.

But, for the avoidance of doubt, that 12z GFS is not a 'mild' run. In fact, synoptically it's a storming run bringing biting north-west through north-easterly winds which would feel bitterly cold: the wind chill off that would be off the scale.

I mean, seriously, you are having a laugh ... right? Look. No, truly, look:

 

I love the synoptics of this. And I'll take a fired jet if it shifts things too. 90% Sizzler will be right that the reload will go mild. But I'll take these odds because one day, boy, are you mild-spectacled folk going to be in for a rude shock. The 10% roll will happen.

This deserves hundreds of likes because some on here can’t read the charts and they go by what people on here post. It’s very annoying when people just say knee jerk comments to try and get a reaction. It’s pretty sad too tbh. Anyway imo it screams battleground with strong wind rain and snow all in the mix, definitely nothing too mild there

[chrisbell-nottheweatherman]

57 minutes ago, ajpoolshark said:

I think it's more a case the phrase 'shortwave' gets used an awful lot in the model thread, and often incorrectly IMHO.....I'm no expert but it's a bit like describing a 'light shower' and a 'thunderstorm' as the same thing.......just a pet peev, I'll go back to grumbling to myself under my breath 

I'm going to head deliberately O/T and ask the Moderators nicely to leave this in given that the Model thread has gone O/T frequently of recent and given that it is (somewhat) model-related - as was said, the feature on the eastern flank of the cut-off low to the west of the Azores is a shortwave as it's a bend in the isobars around a low - the other one bear Greenland is a secondary low as it has a closed circulation.

[Summer Sun]

GEM shows a mild week next week before turning colder for the weekend

[Smiler1709]

Was looking at the cfs a week or so back when all the excitement started with blocking to our north and continued N/NE/E winds showing up on the gfs etc, but the cfs was having none of it. Always showed the high pressure toppling with strong mild SW winds winning through.

i didn't comment because I know the cfs is normally laughed at but I think it's played a blinder here. Our cold spell/snap has been slowly watered down to a brief northerly then back into zonal Atlantic driven weather. I always get a buzz seeing cold charts pop up but in reality the last few years us coldies have had some proper let downs.

really hope the ecm shows something against the grain otherwise I think we're starring down the barrel. 

[russell k]

7 minutes ago, chrisbell-nottheweatherman said:

I'm going to head deliberately O/T and ask the Moderators nicely to leave this in given that the Model thread has gone O/T frequently of recent and given that it is (somewhat) model-related - as was said, the feature on the eastern flank of the cut-off low to the west of the Azores is a shortwave as it's a bend in the isobars around a low - the other one bear Greenland is a secondary low as it has a closed circulation.

Thanks I now know what to look for ("not bears around Greenland" but "kinks in the isobars")

Great explanation 

[Dean E]

5 minutes ago, Smiler1709 said:

Was looking at the cfs a week or so back when all the excitement started with blocking to our north and continued N/NE/E winds showing up on the gfs etc, but the cfs was having none of it. Always showed the high pressure toppling with strong mild SW winds winning through.

i didn't comment because I know the cfs is normally laughed at but I think it's played a blinder here. Our cold spell/snap has been slowly watered down to a brief northerly then back into zonal Atlantic driven weather. I always get a buzz seeing cold charts pop up but in reality the last few years us coldies have had some proper let downs.

really hope the ecm shows something against the grain otherwise I think we're starring down the barrel. 

Cannot agree with you on a zonal outlook. While we get a slight influence from the Atlantic this weekend, with slightly milder uppers moving around the top of the block, there is really no sign of anything like a Atlantic driven pattern.

The Atlantic is likely to be blocked for sometime, it just depends where. 

[Derecho]

21 minutes ago, Smiler1709 said:

Was looking at the cfs a week or so back when all the excitement started with blocking to our north and continued N/NE/E winds showing up on the gfs etc, but the cfs was having none of it. Always showed the high pressure toppling with strong mild SW winds winning through.

i didn't comment because I know the cfs is normally laughed at but I think it's played a blinder here. Our cold spell/snap has been slowly watered down to a brief northerly then back into zonal Atlantic driven weather. I always get a buzz seeing cold charts pop up but in reality the last few years us coldies have had some proper let downs.

really hope the ecm shows something against the grain otherwise I think we're starring down the barrel. 

The pattern over the GFS really isn't zonal, perhaps its geared up for zonal after T384 but that's it.

Yes the GFS is poor for sustained deep cold up until T240 but we can still get some coldish uppers if the winds develop a northerly component, I don't think it would be exciting but I've seen a lot worse.

It actually gets better later on (with a channel low even!) but I don't care for the output after 10 days out.

Edited November 30, 2017 by Quicksilver1989

[northwestsnow]

14 minutes ago, Dean E said:

Cannot agree with you on a zonal outlook. While we get a slight influence from the Atlantic this weekend, with slightly milder uppers moving around the top of the block, there is really no sign of anything like a Atlantic driven pattern.

The Atlantic is likely to be blocked for sometime, it just depends where. 

Unfortunately the 12z GEFS are exactly that in the mid term- infact they look very very wet even for London.

not ruling out transient PM attacks but the overwhelming signal is for Atlantic re-invigoration ...

They GEFS may look better further north i haven't seen them yet.

On a positive note PM attacks may prove of interest for those in NW Britain in particular

Edited November 30, 2017 by northwestsnow

[chris55]

Background trends look to be on the money IMO. Yes we seem to have lost the initial projected northerly after the current cold spell, but instead of a unilateral barrage from the Atlantic we keep seeing  blocking signals and cold incursions. 

Plenty to keep us coldies interested! As highlighted by the GFS 12z

 

[Smiler1709]

9 minutes ago, Dean E said:

Cannot agree with you on a zonal outlook. While we get a slight influence from the Atlantic this weekend, with slightly milder uppers moving around the top of the block, there is really no sign of anything like a Atlantic driven pattern.

The Atlantic is likely to be blocked for sometime, it just depends where. 

Sorry but you can clearly see the Atlantic having a influence on the position of the high pressure, if heights were lower in the med then it could slide under and prop the high up but that isn't the case. High pressure remains in the med so the low pressure systems just steam roller over our high. 

Not saying that won't bring snow or cold conditions because it is coming in from a more northwest angle but these type of set ups are fleeting moments of cold followed by longer periods of milder and wet conditions. Only saying what I can see. 

At least we have we have all winter to get something special ?

[nick sussex]

The reason for my surprisingly upbeat post which I know seems strange given some of my mood swings in here is the scope for improvements if we can overcome the first hurdle.

The first hurdle is between T120 and around T150hrs:

 

The split of that energy to the sw with one separate shortwave low ejecting cleanly, then as the troughing in the east USA sets up it forces a lobe of high pressure east.

 

In the medium term the next attack point will come from the nw, you'd want a weaker low than what the GFS shows later and the question is whether we could see positive heights holding on towards  the ne around that purple area.

 

If we get over the first hurdle then its whether the UK can remain in cold air with a shortwave low ejecting se with snow on its eastern flank.

 

 

Edited November 30, 2017 by nick sussex

[Derecho]

2 minutes ago, nick sussex said:

 

The split of that energy to the sw with one separate shortwave low ejecting cleanly, then as the troughing in the east USA sets up it forces a lobe of high pressure east.

 

 

 

I think this part if it come off would really help develop a big Greenland high, would be difficult to pull off but a possibility.

[karlos1983]

Just remember that whilst the AO is negative we can’t rule out cold chances and at short notice perhaps as well. 

So don’t dispair. I don’t see anything particularly wintry away from high ground on the 12z gfs, but by the time the 18z comes along that could change completely, especially if Frosty gets his crystal ball out .

Hopefully the ECM gives us something to cheer about.

[Dean E]

3 minutes ago, Smiler1709 said:

Sorry but you can clearly see the Atlantic having a influence on the position of the high pressure, if heights were lower in the med then it could slide under and prop the high up but that isn't the case. High pressure remains in the med so the low pressure systems just steam roller over our high. 

Not saying that won't bring snow or cold conditions because it is coming in from a more northwest angle but these type of set ups are fleeting moments of cold followed by longer periods of milder and wet conditions. Only saying what I can see. 

At least we have we have all winter to get something special ?

Totally agree with you regarding the High, we 'ideally' need lower heights over the Mediterranean to enable an easier route for sustained Atlantic block. It's not a requirement but really does boost our chances. 

I can see your point also, but you I'm not sure you are using a good collection of runs, rather than just today's. To say Zonal driven pattern is not correct imo

But yes, I think for the sake of all of us we want to see a back track from todays outputs. 

[Gavin Hannah]

Judging my the outputs I've seen, the word 'Zonal' has no place in the mod thread atm.  Certainly nothing like last few years where we had not a sniff until the new year for a fraction of the cold and snow we've had the last weekish. 

Bring on the pub run.

 

[Optimus Prime]

2 minutes ago, karlos1983 said:

Just remember that whilst the AO is negative we can’t rule out cold chances and at short notice perhaps as well. 

So don’t dispair. I don’t see anything particularly wintry away from high ground on the 12z gfs, but by the time the 18z comes along that could change completely, especially if Frosty gets his crystal ball out .

Hopefully the ECM gives us something to cheer about.

So whilst we're all looking for and expecting extreme December weather (2010/2015) what we are actually more than likely going to get is, ordinary early December weather? 

 

[ACCOUNT DELETED]

 Wow, where has this suddenly come from? Early days but GFS 12z shows some atrocious weather is possible next Friday, severe gales or even storm force wind gusts across parts of the north & west. One to keep an eye on. The outdoor Christmas trees certainly won't like that! 

[karlos1983]

3 minutes ago, Optimus Prime said:

So whilst we're all looking for and expecting extreme December weather (2010/2015) what we are actually more than likely going to get is, ordinary early December weather? 

 

Not sure where I said that to be honest.  

[northwestsnow]

EC looks slightly more amplified at 96 this evening- really hoping we can see an injection of life into the southern arm of the jet

[karlos1983]

3 minutes ago, northwestsnow said:

EC looks slightly more amplified at 96 this evening- really hoping we can see an injection of life into the southern arm of the jet

Yup 96 does look better to me. But maybe a bit early to say.

Thats me sitting on the fence lol

Edited November 30, 2017 by karlos1983
Typo

[northwestsnow]

Just now, karlos1983 said:

Yup 96 does look better to me. But maybe a bit early to say.

Looks better than GFSat said time- different Atlantic profile- energy looks to be primed to split...