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Model Output Discussion - 31/10/2014 and Beyond


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Oh dear another ECM tease, interesting T240hrs chart with a set up that we've seen before, I'm not sure this thread could take another major shortwave drama. For newbies its that small feature near Denmark .

 

The set up goes like this, troughing digs south in the mid Atlantic, nose of high pressure ridges north ahead of this, the shortwave you see near Denmark heads se and high pressure to the ne ridges west over the top.

 

It's one way to an easterly and comes with a Red Warning for fraught nerves and serious drama in this thread!

 

Earlier we saw the ECM separate that troughing which stops the low to the west phasing and heading ne with the PV in tow. This departs from the GFS/GFS P and UKMO view.

Edited by nick sussex
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"Mr Faulty, Mr Faulty! ECM, he go crazy!"

 

ECH1-240.GIF?13-0

 

All a bit of a farce with ECM FI output recently i'm afraid but as Bluearmy stated the Atlantic will hit a wall somewhere to our East, I just think it will be further East than Scandi which would mean Atlantic driven weather for us. If something like the ECM were to come off that could be very good but I fear the pattern would be further East and we would be stuck under stalling lows again.

Rather the Atlantic push through (unless something like ECM verified) with low pressure into Scandi and take a shot at Atlantic ridging behind once the PV has been shunted far enough East. 

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Why is there so much volatility in the models at present?

 

I've heard it said before quite often that model 'Shannon entrophy' or whatever one wants to call it, means an incoming pattern change which the various NWP suites struggle to get a grip on. :shok:  

 

Well at least in the UK over the weekend the winds are largely going to back around into a reverse flow from the East. Feet firmly on the ground with this, but in the overall scheme of things I'm pleased to see a temporary halt of the troughing at its nuisance fronts.

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what is becoming evident is that when the atlantic does come racing in, it is likely to strike a brick wall whcih will drive WAA north into the arctic. that has positive feedback implications re wave breaking into the lower strat but more importantly, we have no idea where this 'wall' is going to be. i doubt it can get too far to our west, but a building scandi high may well be on the agenda if its anywhere in the vicintiy of the meridian. given the strongly modelled polar profile just the other side of the pole, a building scandi ridge could get interesting going forward.

You keep saying the meridian but do you mean 20 degrees west (on gfs) or Greenwich? I think if you mean Greenwich then it really won't impact us. 

Edited by Winter Frost
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The Models as expected have backtracked a LONG way today, even the ECM- however the GFS has been hopeless.........

 

 

http://www.meteociel.fr/modeles/ecmwf/runs/2014111312/ECH1-216.GIF?13-0

 

Phantom Easterly coming.

 

S

I would suggest Steve that the Gfs has been a better player than Ecm recently..... :cc_confused:

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If I just showed the first chart and said an easterly was on its way you'd be thinking what!

 

post-1206-0-13893400-1415906410_thumb.gi

 

Many easterlies have been preceded by warm southerlies and you can see the transition here:

 

post-1206-0-23940100-1415906515_thumb.gi

 

post-1206-0-20036900-1415906531_thumb.gi

 

post-1206-0-33194500-1415906552_thumb.gi

 

post-1206-0-07841700-1415906572_thumb.gi

 

 

The key really is to get that dig south of the jet in the mid Atlantic as this helps to force the high to ridge north ahead of it, the ECM T240hrs isn't quite there but something to watch out for however the earlier timeframe is important because we want the pattern to back west, so we want the ECM to be correct by not phasing that shortwave and running it ne.

 

And of course another key area is to the ne in terms of high pressure, its a big longshot at present but something to look out for in the coming days. The last time the ECM departed from the consensus within the T144hrs was the spoiler shortwave nearer southern Greenland which proved correct. Lets hope its on the right track here at that point.

 

 

 

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Aren't you predictable :good:

 

 

Yes I just want that PV lobe to flush into the Atlantic so the pattern can reset. That will allow a pressure rise somewhere in the Atlantic; a default pattern of late in GEFS FI, so when we get the trop warming from the strat then maybe the setup will favor the UK. If we maintain this current ScEuro block with the Atlantic train sloshing NE to our west, or troughing to our SE, or both, there remains no quick route to cold, and when the reshuffle happens in early December it may be the US that gets the cold again.

 

So yes I am keen on the GFS way forward. We have to move on; we have missed this shot at cold, there will probably be one more this year, lets shuffle the metaphorical pack and see how lucky we are next time :p

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Surely we have to benefit from the state of the PV......................................don't we??????

 

 

Chino (Ed) in the Stratosphere and on Twitter has been concerned that the Wave 2 which seems to be coming through on the models is not favorable for Cold in the UK.  Not too sure about that, but he is a very knowledgeable person when it comes to those matters.

 

From my perspective when the Northern Hemisphere looks like it does this year many things are possible which should be tottaly different from last year.  The westward shift in the models this afternoon actually goes against the grain of what a lot of much more experinced individuals thought was going to be shown today.  And I think it has given them a little surprise.  How long this continues remains to be seen.  I also seem to remeber that we need the PV to either be split or displaced for us to get a good chance at cold weather in the UK, but then again it is a chance and other things also have to fall into place for us to get the cold shot we want or that many of us want.

 

More runs needed.As usual.

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Yes I just want that PV lobe to flush into the Atlantic so the pattern can reset. That will allow a pressure rise somewhere in the Atlantic; a default pattern of late in GEFS FI, so when we get the trop warming from the strat then maybe the setup will favor the UK. If we maintain this current ScEuro block with the Atlantic train sloshing NE to our west, or troughing to our SE, or both, there remains no quick route to cold, and when the reshuffle happens in early December it may be the US that gets the cold again.

 

So yes I am keen on the GFS way forward. We have to move on; we have missed this shot at cold, there will probably be one more this year, lets shuffle the metaphorical pack and see how lucky we are next time :p

 

To digress slightly did you notice the tropopause. was below the 500mb level over Dakota yesterday which apparently upset the GOES Sounder total column ozone values. I don't know how this works now but back in the day it was not reported as a trop if below 500mb. Technically speaking if the lapse rates falls below a certain value it is.

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Another year gone and here were are!!Mo for me has started early with its unusual nh synoptics.The fact is this autumn has and does look nothing like last year regarding the pv and the current ups and downs on the models ete.If i was a betting man and with the ao going slightly positive then id say an unsettled spell of weather is on the cards but not our usual zonal type

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Lets not kid ourselves the Atlantic is in full control, brief ridges yes, out to the silly time of day ten gfs and ecm differ. Surprise, surprise gfs still keeps the Atlantic awake ,Ecm  throws a nice ridge over the Uk .I wish Ecm was on the money....Normal British Weather.... :good:

post-6830-0-58187100-1415908738_thumb.pn

post-6830-0-26433700-1415908841_thumb.pn

Edited by ANYWEATHER
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So my view from the models.

GFS - too mobile and progressive with the Atlantic

ECM - Too slow and amplified, that wedge of heights over the UK is way to far west.

In the end once the dust settles (say Saturday) we will see a similar pattern over Europe as we see now. Low heights and troughing near the UK, a ridge to our east and a generally southerly flow.

The GFS ens never really get low pressure west of the UK even into week 2 onwards. Probably suggest that we will keep a similar pattern to now

gensnh-21-1-240.png?12

gensnh-21-1-384.png?12

I suspect we will continue to see rather wet conditions for the foreseeable, along with near average temperatures. Personally I don't see this changing for quite a while.

That said, anyone looking for cold, I would say it's more likely to come from the east than the north.

Edited by Captain shortwave
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And of course another key area is to the ne in terms of high pressure, its a big longshot at present but something to look out for in the coming days. The last time the ECM departed from the consensus within the T144hrs was the spoiler shortwave nearer southern Greenland which proved correct. Lets hope its on the right track here at that point.

Actually Nick I think GFS (p) picked up on the shortwave before ECM and I posted about it on the 9th. Here are the charts from that day. (Can't get the parallel but I think my post will still show it from the 9th)

 

GFS/ECM 9th 168 forecast 00z against GFS current

 

gfsnh-2014110900-0-168.png?0ECH1-168.GIF?00gfsnh-0-60.png?12

 

 

ECM has not been performing well of late although usually it is better than GFS. Here are the FI predictions against ECM current predictions from the 9th. Again we see GFS appears to of handled this much better.

 

GFS/ECM 12z 192 forecast against ECM current

 

 

gfsnh-2014110912-0-192.png?12ECH1-192.GIF?12ECH1-96.GIF?13-0

 

None of that means it is wrong tonight but given the difference between its evening and morning run and other than GEM it has little support for how it pushes the low SW of Ireland I would definitely want to see some consistency before getting remotely caught up in another ECM FI Easterly Goose chase.

 

It will be a major coup if it right though. :clapping:

Edited by Mucka
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You keep saying the meridian but do you mean 20 degrees west (on gfs) or Greenwich? I think if you mean Greenwich then it really won't impact us.

I keep saying meridian? Anyway, I mean in the general longitudinal vicinity of the uk. And if it's thw Greenwich meridian and WAA is stuck up to svaalbard, you would be surprised how a building Scandi block might subsequently Impact us

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To digress slightly did you notice the tropopause. was below the 500mb level over Dakota yesterday which apparently upset the GOES Sounder total column ozone values. I don't know how this works now but back in the day it was not reported as a trop if below 500mb. Technically speaking if the lapse rates falls below a certain value it is.

 

 

No i didn't see that but I believe it could be a Tropopause Fold. North Dakota is a known hot spot for that. Not sure of its precise definition but something to do with stratospheric air wrapping under the jet streak and intensifying a LP system.

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Mucka I'm not sure of the relevance of those outputs in terms of the divergence tonight. The ECM departs from the GFS at T120hrs.

 

As for the later ECM output well into FI its a longshot especially because of the recent wild swings of the ECM past T168hrs however for the timebeing I'm more interested in seeing how the NWP resolves the trough disruption before then.

 

If high pressure holds near Svalbard then its pretty important to see how far east those low heights get near Greenland.

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No i didn't see that but I believe it could be a Tropopause Fold. North Dakota is a known hot spot for that. Not sure of its precise definition but something to do with stratospheric air wrapping under the jet streak and intensifying a LP system.

 

info on that below

http://www.atmos.umd.edu/~dkuhl/documents/Kuhl_Tropopause_Folding.ppt#274,2,Overview

or

http://www-das.uwyo.edu/~geerts/cwx/notes/chap01/tropo.html

 

I suspect quite a bit of this may be new to knocker as an ex 'upper air' man, it certainly is to me as an ex ' bench forecaster'. This site is marvellous for extending ones knowledge-thanks folks

Edited by johnholmes
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info on that below

http://www.atmos.umd.edu/~dkuhl/documents/Kuhl_Tropopause_Folding.ppt#274,2,Overview

or

http://www-das.uwyo.edu/~geerts/cwx/notes/chap01/tropo.html

 

I suspect quite a bit of this may be new to knocker as an ex 'upper air' man, it certainly is to me as an ex ' bench forecaster'. This site is marvellous for extending ones knowledge-thanks folks

 

Second link okay John but can't seem able to open the first for some reason.

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^^^ Thanks John.

 

The ECM mean is similar to this morning, with the Atlantic slowly breaking through.

 

D10: post-14819-0-25224800-1415910931_thumb.g

 

Update re Wave 2 from WSI:

 

 

WSI_Energy
While there was a wavenumber-2 forcing signature on the stratosphere polar vortex, likely a failed event. Patience. http://t.co/YlGlCgVydp
11/13/14, 7:51 PM

 


Second link okay John but can't seem able to open the first for some reason.

 

You may need MS Powerpoint.

 

Converted to PDF: Kuhl_Tropopause_Folding.pdf

Edited by i'm dreaming of...
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No i didn't see that but I believe it could be a Tropopause Fold. North Dakota is a known hot spot for that. Not sure of its precise definition but something to do with stratospheric air wrapping under the jet streak and intensifying a LP system.

 

Interesting i'm. It was reported at 12 yesterday and this was the 300mb chart.

post-12275-0-75422400-1415911443_thumb.p

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^^^ Thanks John.

 

The ECM mean is similar to this morning, with the Atlantic slowly breaking through.

 

D10: attachicon.gifEDM1-240-4.GIF

 

Update re Wave 2 from WSI:

 

 

WSI_Energy

While there was a wavenumber-2 forcing signature on the stratosphere polar vortex, likely a failed event. Patience. http://t.co/YlGlCgVydp11/13/14, 7:51 PM

 

 

You may need MS Powerpoint.

 

Converted to PDF: attachicon.gifKuhl_Tropopause_Folding.pdf

but that is 360 hours out! ! Its ridiculous assuming that its more than likely gona be a failed event! ! Unless there on about a current attack that's happening at the moment! !
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