Model Output Discussion 18th Nov.2013-12z onwards.

[minus 9]

Models only show what might happen. Not what will happen. Probably be different tomorrow.

[OldMetMan]

A warm wellcome back to the forum OMM.

Thank you kindly PM, hope I will be around more from hereon, had a few health issues earlier this year, gradually getting back in circulation!OMM

[Mark Bayley]

The GFS 12z highlights perfectly how volatile the model output can be. I would suggest its probably gone off on one, and some sort of northerly incursion is still quite likely, although will see what the ECM churns out. Current stratospheric conditions (increased zonal winds and lower than average temperature) will inhibit any sort of prolonged high latitude blocking, although will not prevent colder spells from occurring. However, anything other transient northerlies i would suspect is unlikely, at least until we see some sort of notable warming event. Having a quick look at the MJO and there seems general consensus, at least form the ECM and GFS, for progressing it into phase 2/3 as we progress into December. This gives the following composites, the later lending some support for heights being centred more in the Atlantic, allowing for brief northerly incursions. Not really had to time to look at the data in detail, far to many university essays, although hopefully past Christmas i'll be able to post more!

Edited November 28, 2013 by Mark Bayley

[legritter]

ok ,not the sort of GFS run coldies would wont to see ,but at this range the next run could be totally different by miles and anyhow that low to our n/west could dive s/east .Lets wait till the ECM comes out later for a fuller picture ,i would love for a Stella run but would just prefer some constant build up in good synoptics .So keep the faith ,no throwing in the towell  ,take a deep breath its always going to be  a rollercoaster ,and there is some seriouse cold waiting in the wings  ,and theres always tomorrow in this Game ..

[SMU]

Basically in a nut shell-

 

The separation of energy from the 06z GFS, UKMO & ECM allows a SLOW solution from the secondary low-  this will then allow ridging between the atlantic high & the east coast High -

 

Theres 4 key things to look for :

 

Seperation of energy

Shallow lows

Atlantic high ridging in the middle

Canadian high building from the PNA ridge

 

 

A very complicated pattern that seemed resolved earlier- 

 

REMEMBER THE GFS CANNOT SEPERATE ENERGY & AREAS OF PVA VERY WELL - So tends to morph them together into super lows.

 

I agree with the person who posted above- weather is ALL about timing - it always has been & always will be- for us to get that super Northerly there needs to be a shallow low moving across southern Greenland at X time to then phase & sweep the cold air south.

 

1 thing I wont ever do though is take the eastward biasing GFS for gospel over the ECM operational.

 

S

[Methuselah]

^^ I agree, Mark - the models give us great insight into potential developments (and indications of the current state of the atmosphere), but they are not crystal balls...Moreover, they exert no control whatsoever over the weather...

Basically in a nut shell-

 

The separation of energy from the 06z GFS, UKMO & ECM allows a SLOW solution from the secondary low-  this will then allow ridging between the atlantic high & the east coast High -

 

Theres 4 key things to look for :

 

Seperation of energy

Shallow lows

Atlantic high ridging in the middle

Canadian high building from the PNA ridge

 

 

A very complicated pattern that seemed resolved earlier- 

 

REMEMBER THE GFS CANNOT SEPERATE ENERGY & AREAS OF PVA VERY WELL - So tends to morph them together into super lows.

 

I agree with the person who posted above- weather is ALL about timing - it always has been & always will be- for us to get that super Northerly there needs to be a shallow low moving across southern Greenland at X time to then phase & sweep the cold air south.

 

1 thing I wont ever do though is take the eastward biasing GFS for gospel over the ECM operational.

 

S

And, neither can anything (or anyone) else?

[MR EXTREMES]

I think when you got ukmo and gfs side by side it does seem more likely that tomorrows met update would likely read cold in the north and milder in the south.

[The Northern Ramper]

It this going to be another example of the Gfs picking up the correct solution early, only to drop it when others come on board and reclaim it nearer the time?

[Severe Siberian icy blast]

Oh deer . . . .

its something we all should be use to by now . Which is why I never read into things more than t144 away . Not saying this is right of course. But I am quite confident the final jury will be a much more watered down version of events than what the gfs/ecm had this morning. Simply because the models over react to pattern changes when they pick up a signal first. They then completely drop it as we draw closer , to pick it back up again nearer the time with a more realistic look. But we also know many times especially northerlies things move East dramatically nearer the time. So dont be surprised if we dont get anything out of it. My advise if you dont want to be burnt with fire. Do not take model individual runs literally .

[SMU]

http://www.meteociel.fr/ukmo/runs/2013112812/UW144-7.GIF?28-17

 

Whoever posted the UKMO NH 850s @ 144 thanks- that's great to have- always frustrating to only go to 72 before-

So UKMO day 6 sees the -6 line already into Scotland... -4c creeping south.

 

Anyone doing Ensemble watch?

 

S

[Frosty.]

I have seen the future..this evenings ecm 12z will be an emotional rollercoaster :-)

[TwisterGirl81]

I just had a look at GFS 500hpa and SLP....the northerly next weekend appears to be very much a 'northerly event'

Going by the charts it may just be cold In the south every bl**dy time....let's just hope it upgrades again as it would be lovely for something festive leading up to Christmas

Edited November 28, 2013 by TwisterGirl81

[SMU]

http://www.meteociel.fr/modeles/ecmwf/runs/2013112800/ECH1-144.GIF?28-12

 

Its there mucka just a small wave south of that 1015 low over SW Greenland- that's how little the ECM made of its ability to deepen-

but a large separation from the parent low allowing ridging down the line

http://www.meteociel.fr/modeles/ecmwf/runs/2013112800/ECH1-168.GIF?28-12

from the Canadian high & atlantic high

 

S

[Mucka]

http://www.meteociel.fr/modeles/ecmwf/runs/2013112800/ECH1-144.GIF?28-12

 

Its there mucka just a small wave south of that 1015 low over SW Greenland- that's how little the ECM made of its ability to deepen-

but a large separation from the parent low allowing ridging down the line

http://www.meteociel.fr/modeles/ecmwf/runs/2013112800/ECH1-168.GIF?28-12

from the Canadian high & atlantic high

 

S

 

 

I posted exactly the same thing in a detailed reply to Captain Shortwave also mentioning how hard it is to pick up detail on the ECM with its 24h steps but for some reason unbeknown to me it got removed. Mods?

 

 

As for an ensemble watch, they are out to 144h and the best I can say is they are scrambled.

Plenty splitting the energy including the control but amplification of the pattern and position of trough/ridge are all over the place so it would be hard to garner anything from how the low phases with it later.

Edited November 28, 2013 by Mucka

[dallas]

Blimey, not saying the 12z is wrong, but is it normal for there to be that much disparity on the same model fromit's previous run?

[Methuselah]

I posted exactly the same thing in a detailed reply to Captain Shortwave also mentioning how hard it is to pick up detail on the ECM with its 24h steps but for some reason unbeknown to me it got removed. Mods?

Not sure, Mucka...Was that the one that was no more than a re-post of a previous post? 

[Captain Shortwave]

http://www.meteociel.fr/modeles/ecmwf/runs/2013112800/ECH1-144.GIF?28-12

 

Its there mucka just a small wave south of that 1015 low over SW Greenland- that's how little the ECM made of its ability to deepen-

but a large separation from the parent low allowing ridging down the line

http://www.meteociel.fr/modeles/ecmwf/runs/2013112800/ECH1-168.GIF?28-12

from the Canadian high & atlantic high

 

S

Cheers, consider myself corrected 

^I believe some people still can't quote posts properly after the forum upgrade, the response was probably within the post that was quoted.

Edited November 28, 2013 by Captain shortwave

[Methuselah]

Blimey, not saying the 12z is wrong, but is it normal for there to be that much disparity on the same model fromit's previous run?

Quite normal, dallas...What seem massive deviations, in our tiny corner of the world, are often quite trivial when taking the NH as a whole...

[Mucka]

Not sure, Mucka...Was that the one that was no more than a re-post of a previous post? 

 

LOL No!

It was a reply to Captain Shortwave on how it was difficult to pick up split energy on the ECM between 120 and 144 as it had 24h steps and that I believed it had ejected a shortwave into the trough through that period. I then blathered on about a lot of other things to be fair, still

[Frosty.]

Blimey, not saying the 12z is wrong, but is it normal for there to be that much disparity on the same model fromit's previous run?

Yes, you only have to go through the GEFS perturbations to see the enormous differences, the fat lady is not singing yet though.

[dallas]

Quite normal, dallas...What seem massive deviations, in our tiny corner of the world, are often quite trivial when taking the NH as a whole...

 

Thanks,should have thought of that, awaiting the ECM and UKMO with interest

[Joe Levy]

Ensemble mean at 228 hours. There are a variety of options available, some closer to the op, but most not. This could go down to the wire potentially

[radiohead]

Blimey, not saying the 12z is wrong, but is it normal for there to be that much disparity on the same model fromit's previous run?

 

Small changes early on will snowball to bigger and bigger changes the more distant a particular event is, considering the "event" we're all looking at is out in "FI"-land then it's not surprising at all to see intrarun variance like this. The previous GFS and ECM operational runs were also colder than the majority of the ensembles, so a less cold run is not surprising. This could be a move too far in the other direction though, it could be an outlier at the other end of the scale, we'll see shortly.

[BLAST FROM THE PAST]

But OP is run at higher res than mean?  A lot to go through and more ups and downs I think through December

 

BFTP

[radiohead]

 

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Edited November 28, 2013 by radiohead