Model Output Discussion - 05/01/2016 18z onwards

[i luv snow]

7 minutes ago, Geordiesnow said:

To be fair, I think his analysis could well be spot on regarding it will be brighter and quite dry next week but there will be some showers around however I think the emphasis will be more on that it will be dry, chilly and sunny, the PPN charts do reflect this. Regarding the other part of his view on the outputs, Its too early to say what will happen. 

In terms of this mornings output, if the cold air is slightly more modified then I certainly won't be digging any snow shovels out just yet, the air might be barely cold enough for any showers to fall as snow nevermind settling snow. 

But we have been there before, get the cold in, then worry about precipitation at +24 (or less). PPN charts, as inaccurate as they usually are, often show little (although some are showing copious amounts this morning), only for PPN to crop-up at the last minute. Yes, the opposite happens too. One thing is for sure, it will be getting a lot colder, cold enough for snow across most of the UK, period. And we have to hope the ppn comes with it! Which I think the current models are suggesting it will..

Edited January 7, 2016 by i luv snow

[Geordiesnow]

4 minutes ago, karlos1983 said:

Hi Geordie

I have to agree with you. Im in a state of unease this morning. After being on cloud 9 after the 12z of yesterday, I found the 18z from the GFS worrying. Although I'm confident a cold outbreak is almost certain, I'm still a little underwhelmed this morning RE longevity, more particularly for those further south. I've been watching the Low that has been key for me to keeping the Atlantic ridge joining the Greenland High for days now and I must admit not for 1 minute did I consider that it might spin off another low and attack the south coast as early as it is being modelled this morning.

I do take some relief in the extended ECM Steve M has recently posted, which does suggest that it may have overdone the intensity of the low and what trajectory it takes, I prefer more E than NE.

Certainly very interesting nonetheless.

 

Overall still good synoptics, but I'm keeping my excitement held back for a bit longer yet, especially for my area. No question areas of the Midlands North could get a pasting from the 168 chart.

I'm probably a little more concerned at the watering down and delay(compared what the Euro models were showing, even Peter Gibbs said middle part of next week for the cold to really dig in which certainly what was not said on yesterday's forecasts) of the initial NW'ly flow, that caught me out somewhat because whilst its still there, it does not look as potant and what showers that are there could well be more of a watery type with the more modified air around, still should be cold with some frost around mind. I do hope the models have that trigger low further Eastwards again as quick as they did because then we get the colder air in quicker and its less likely to be modified also. 

Some good news regarding the continuation of Greenland heights though and I'll worry about the details in the medium term closer to the time as they will no doubt vary from run to run. 

[winterof79]

13 minutes ago, Geordiesnow said:

To be fair, I think his analysis could well be spot on regarding it will be brighter and quite dry next week but there will be some showers around however I think the emphasis will be more on that it will be dry, chilly and sunny, the PPN charts do reflect this. Regarding the other part of his view on the outputs, Its too early to say what will happen. 

In terms of this mornings output, if the cold air is slightly more modified then I certainly won't be digging any snow shovels out just yet, the air might be barely cold enough for any showers to fall as snow nevermind settling snow. 

Could you back that up with a couple of charts regarding not cold enough for showers to fall as snow please Geordie

http://www.meteociel.co.uk/modeles/ecmwf.php?ech=192&mode=0&map=3&type=0&archive=0

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=144&mode=1

Edited January 7, 2016 by winterof79

[bluearmy]

19 minutes ago, Shuga ice said:

I understand your point but I see the outputs playing with different scenarios.   The outputs do look stunning but I really can't see the Atlantic playing ball to the extent shown.  Remember, last week there was no sign of anything but mild, wet weather showing with a lot of despondency in here.  I am just taking the middle ground view.  It's pointless having a forum where you are only safe to post snow and cold possibilities and be berated when your view is the opposite.

tonights outputs may show a great outlook for cold but there is also a chance that they may start to get watered down.

I hope for cold snowy weather but it isn't in the bag yet!

Shuga, assuming you are genuine and not on a wind up, you should look back at the posts being made by the some of the more experienced members of the forum (around the time that Steve was expecting the models to flip easterly which sadly they didn't).  that's the best part of a week ago now.  The main thought process was that we could well see a n Atlantic ridge develop and that we should be looking nw for blocking, not ne.  This evolution, though generally unexpected hasn't just appeared from nowhere. If you looked at the anomolys and evolutions from run to run, it was a potential place to be for mid jan. I'm not a forecaster but I recall posting that the scrussian block wouldn't bring cold as the Atlantic trough was too strong. That we should be looking nw for our next chance of countrywide cold by mid January. 

so yes, be cautious by all means but don't post what the NWP isn't showing. It's currently showing a definitive cold spell of several days followed by

a) Azores low runs sw/ne and brings snow/rain depending on how much it deepens/phases with the trough already in place. Likely to be followed by a resumption of the cold trough and n feed.

b) Atlantic ridge collapses slowly se across the UK and allows a westerly regime to take over. I would expect further upstream amplification to retrogress this back and give a broad repeat of the pattern but that's is open to conjecture at this time

c) sceuro trough maintains a n/ne feed and cold with snowfall in the usual favoured locations. No way of anticipating where we would see troughs in the flow to bring stuff inland

d) Atlantic  ridge extends ne towards n Scandi introducing a general ene flow across the uk

the only option that sits with your assessment is option b.  Granted that this was probably the favoured MOGREPS option based on yesterday's meto outlook but I expect that model to begin to change its view now.

 

 

[coldcomfort]

4 minutes ago, Geordiesnow said:

To be fair, I think his analysis could well be spot on regarding it will be brighter and quite dry next week but there will be some showers around however I think the emphasis will be more on that it will be dry, chilly and sunny, the PPN charts do reflect this. Regarding the other part of his view on the outputs, Its too early to say what will happen. 

In terms of this mornings output, if the cold air is slightly more modified then I certainly won't be digging any snow shovels out just yet, the air might be barely cold enough for any showers to fall as snow nevermind settling snow. 

Reluctantly I have to agree GS, at least for now. From the middle of next week the uppers on both GFS and ECM look low enough to see falling snow, albeit of the wet variety away from hilly areas, but the very wet and lets be honest very warm ground will not be ideal for lying snow beyond any temporary wet covers. ECM of course does offer a different 'potential' senario of deep LP bringing rain and/or sleet to the south and blizzards for central areas which would clearly lay down a significant cover, but it's all speculation at this juncture. Let's get the LP developed first today and see where it starts to drift tomorrow/Saturday. 

[No Balls Like Snow Balls]

From Twitter

 

 

 

[nick sussex]

Typical the GFS backtracks and now looks much safer in terms of margin for error. Both the ECM and UKMO I don't like because of the phasing with the energy ejected of that Azores low. The UKMO in particular throws up a ridge towards Iberia.

If you're going to have the ECM you need a much shallower feature running ne. As I said last night playing poker with the pattern too far west is liable to end in tears.

Hurdle 1 overcome however issues surrounding the Azores low and how far east/west the pattern is remains.

I might be going against the tide in here this morning but after the GFS backtrack the Euros leave me underwhelmed.

[Frosty hollows]

23 minutes ago, Polar Maritime said:

Post are having to be hidden again, Just sensible/friendly 'Model Discussion' please in here otherwise your post will go missing, There are banter/winter threads open. Please back up post's with charts/evidence as 100's come on here for valuable information. .

Thanks. 

OT...but thanks for keeping the discussion flowing. As an amateur. I'd never dare contribute to this thread, but am really interested in learning how forecasts are made (and any chance of white stuff). It's really off putting to have to wade through too much irrelevance , so from my pov, the modding is much appreciated! (Creepy post over. As you were ppl)

[Geordiesnow]

5 minutes ago, i luv snow said:

But we have been there before, get the cold in, then worry about precipitation at +24 (or less). PPN charts, as inaccurate as they usually are, often show little (although some are showing copious amounts this morning), only for PPN to crop-up at the last minute. Yes, the opposite happens too. One thing is for sure, it will be getting a lot colder, cold enough for snow across most of the UK, period. And we have to hope the ppn comes with it! Which I think the current models are suggesting it will..

Indeed that is correct but at this stage you would say looking at the models, you would go more on the emphasis on the drier weather than snowy weather for next week so I don't think the analysis posted by Shuga Ice is totally off the mark in fairness. I would of agreed on the cold enough for snow for most of the UK basing on yesterday's outputs but today's output has modified the cold air somewhat(thanks to the faffing on of the trigger low) so I'm less confident about any PPN being truely of snow unfortunately. 

Obviously any low coming up from the SW which might engage with that cold air could change the dry output to a potential more snowy(and for some wet) outlook but I much rather this does not happen as the air over us is not all that cold for a proper battleground set up. 

[Troubleatmill]

9 minutes ago, karlos1983 said:

Hi Geordie

I have to agree with you. Im in a state of unease this morning. After being on cloud 9 after the 12z of yesterday, I found the 18z from the GFS worrying. Although I'm confident a cold outbreak is almost certain, I'm still a little underwhelmed this morning RE longevity, more particularly for those further south. I've been watching the Low that has been key for me to keeping the Atlantic ridge joining the Greenland High for days now and I must admit not for 1 minute did I consider that it might spin off another low and attack the south coast as early as it is being modelled this morning.

I do take some relief in the extended ECM Steve M has recently posted, which does suggest that it may have overdone the intensity of the low and what trajectory it takes, I prefer more E than NE.

Certainly very interesting nonetheless.

 

Overall still good synoptics, but I'm keeping my excitement held back for a bit longer yet, especially for my area. No question areas of the Midlands North could get a pasting from the 168 chart.

Indeed ref the t168 chart mate, I would of thought that would not be decided until well nearer the time. Rule of thumb would be the deeper the low the higher the latitude of its track, but not sure if that is still the case when its originating from so far south?? not worth being despondent or excited regarding this feature yet do you reckon?     

[Alexis]

It's simply incorrect to label this 'dry and chilly' when Scotland is anything but and troughs are not visible at this stage. Don't see how a trough of evening sleet and snow showers pushing in off the Irish Sea could be discounted, for example, either. The kinks indicated a cold front to the north west as well.

 

Edited January 7, 2016 by Alexis

[nick sussex]

8 minutes ago, Geordiesnow said:

Indeed that is correct but at this stage you would say looking at the models, you would go more on the emphasis on the drier weather than snowy weather for next week so I don't think the analysis posted by Shuga Ice is totally off the mark in fairness. I would of agreed on the cold enough for snow for most of the UK basing on yesterday's outputs but today's output has modified the cold air somewhat(thanks to the faffing on of the trigger low) so I'm less confident about any PPN being truely of snow unfortunately.

Obviously any low coming up from the SW which might engage with that cold air could change the dry output to a potential more snowy(and for some wet) outlook but I much rather this does not happen as the air over us is not all that cold for a proper battleground set up.

You make a good point. The ECM low is too deep and the angle isn't great, this will mix out too much of the cold. You need to see a more oval low running further south and exiting over northern France not the North Sea.

 

 

Edited January 7, 2016 by nick sussex

[Geordiesnow]

12 minutes ago, winterof79 said:

Could you back that up with a couple of charts regarding not cold enough for showers to fall as snow please Geordie

http://www.meteociel.co.uk/modeles/ecmwf.php?ech=192&mode=0&map=3&type=0&archive=0

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=144&mode=1

I can tell you from experience those uppers are more than likely not cold enough, especially closer to the coast you are and the showers at this stage are not forecast to fall too far inland(as of yet). You need a off shore wind for any PPN with those uppers to fall as snow from my experiences in the North East. 

If today runs are more right regarding the slower pace of the trigger low then it really is going to be a bit of a waiting game to get that colder air too flood down, as Peter Gibbs alluded too, it could actually be in the middle part of next week for it too happen which is a shift from Sunday/Monday that the Euro models did forecast.

[karlos1983]

5 minutes ago, Nicholas B said:

Indeed ref the t168 chart mate, I would of thought that would not be decided until well nearer the time. Rule of thumb would be the deeper the low the higher the latitude of its track, but not sure if that is still the case when its originating from so far south?? not worth being despondent or excited regarding this feature yet do you reckon?     

Well perhaps not, but It's is ultimately going to decide the fate of the south of the UK imo. But like you say much time to nail down detail on that. I would prefer it didn't spin another low off and phase with the Trough over the UK to be honest, but I'm not sure if that's an option to be fair.

Edited January 7, 2016 by karlos1983

[bradymk]

7 minutes ago, nick sussex said:

Typical the GFS backtracks and now looks much safer in terms of margin for error. Both the ECM and UKMO I don't like because of the phasing with the energy ejected of that Azores low. The UKMO in particular throws up a ridge towards Iberia.

If you're going to have the ECM you need a much shallower feature running ne. As I said last night playing poker with the pattern too far west is liable to end in tears.

Hurdle 1 overcome however issues surrounding the Azores low and how far east/west the pattern is remains.

I might be going against the tide in here this morning but after the GFS backtrack the Euros leave me underwhelmed.

Yes but thankfully the EPS much less keen on that system getting as far north and as deep as how the op showed. We'll see what it shows tonight but luckily for us, we know a system like that at day 7/8 coming up from the Azores is not going to be modelled very well. 

[winterof79]

OK So everyone is getting wound up/in with the "possible" azores low at day 7 and how it will track.

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=144&mode=1

We know the track will change but wherever it does it will hit very cold air and then drag more cold air in.

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=144&mode=1

Stop fretting too much some will get dumped on others wont thats life.If you are anywhere midlands North it is far from underwhelming output just variances.

[Nick L]

20 minutes ago, Geordiesnow said:

I can tell you from experience those uppers are more than likely not cold enough, especially closer to the coast you are and the showers at this stage are not forecast to fall too far inland(as of yet). You need a off shore wind for any PPN with those uppers to fall as snow from my experiences in the North East. 

If today runs are more right regarding the slower pace of the trigger low then it really is going to be a bit of a waiting game to get that colder air too flood down, as Peter Gibbs alluded too, it could actually be in the middle part of next week for it too happen which is a shift from Sunday/Monday that the Euro models did forecast.

To be fair, looking at the latest EC, you have a point. Theta-Ws are often just above zero for many areas, when for settling snow you really want them below zero. That beasty "channel low" on Thursday would be one big sleety mess. However, on previous EC runs it was much colder, if drier. It's a bit of a nightmare for my 6-10 day forecasts into next week! But as we've seen on many occasions, precip can often pop up at short notice.

[Harsh Climate]

Checked this mornings runs and we still have the BIG THREE emphatically on board (GFS,ECM/UKMO) with momentum building on a potentially great cold spell! Must admit I was kind of hiding behind my computer seat whilst checking the charts this morning as a downgrade would have been gut wrenching. If anything IMO we have an upgrade, rather than a predominantly dry northerly flow we are now looking at a  more unstable NE flow .

 

My favourite charts of the morning:

ECM 240

This looks very victorian winteresque with the level of cold just gradually creeping up on us with the potential of reloads injecting some serious deep cold over the uk!

 

 

Now I'm sorry but this on the gfs 00z is just sick:

 

one metre of snow in a strengthening easterly gale anyone?? 

Edited January 7, 2016 by Harsh Climate

[BarnetBlizzard]

For those who are less able at reading the charts (such as myself) here is what the latest GFS chart shows. 

For me, the GFS 6z looks better in terms of the threat of the azores low (less of an interference) . Also, the way the high is positioned means a north easterly wind is brought in bringing colder uppers, this has been a bit of a trend overnight and this morning. 

     The next few frames should show cold uppers coming in from the North/ North east. 

Edited January 7, 2016 by BarnetBlizzard

[Polar Maritime]

The 6z continues the theme into next week, With strong ridging into Greenland drawing a cold dry Northerly type flow with overnight frost's and Snow for some.

 

Edited January 7, 2016 by Polar Maritime

[coldcomfort]

06 suggests getting this pattern east is going to be like pulling teeth with rusty pliers, but on the plus side it keeps the Az low at bay and eventually introduces a NE'erly. Interesting times ahead and one that will throw up many more emotional highs and lows before the fat lady eventually bursts into song.

[radiohead]

06Z GFS...Looks fantastic.

 

[PolarWarsaw]

Slightly 'MEH' runs comparatively overnight for me. Now, don't get me wrong. Things still look cold and frosty for a period of next week, but snow chances have been reduced for a good chunk of the country on this mornings runs, they are certainly more marginal anyway. The 18z picked up on a smaller ridge last night, but this morning we have a spoiler low down to the SW and this makes me feel very uneasy. If the low wants to play ball, we need it to be shallower, moving slowly north east and in the shape of an oval - not a small football. 

That's definetely what we need to watch on the 6z and particularly the 12z this evening - if it's going to play ball it's weaker, slower moving and less of an issue...if it doesn't it will blow up and potentially shorten/ruin snow chances for a lot of low level England. 

Let's see if it's a trend or just the models blowing up a low to our west/south west as per usual. 

[North East Blizzard]

Can't really complain about the 6z, maybe takes a liitle longer for the real cold to hit, but I can't imagine anything but snow from Tuesday onwards anywhere Midlands north, especially away from the coast and with a little elevation  

Think I'm safe this high up!

[Geordiesnow]

3 minutes ago, Nick L said:

To be fair, looking at the latest EC, you have a point. Theta-Ws are often just above zero for many areas, when for settling snow you really want them below zero. That beasty "channel low" on Thursday would be one big sleety mess. However, on previous EC runs it was much colder, if drier. It's a bit of a nightmare for my 6-10 day forecasts into next week! But as we've seen on many occasions, precip can often pop up at short notice.

Maybe the ECM has not backtracked as much with the trigger low as I seem to be suggesting when you compare it with the UKMO and especially the GFS now but even so, you still like that trigger low to be further eastwards so we get some colder air in quicker and therefore slightly stronger which may help any battleground situation. 

Its a good GFS run in respect of maintaining the trend of pushing WAA into Greenland and getting a Greenland high, the detail is rather slack and messy though and be subject to change. Shame it still want to drag it heels regarding moving that trigger low but I think this will be the case now, just hope it won't be as slow as the GFS and this morning's UKMO run!