Model Output Discussion 13/11/13 >

[johnholmes]

I'm sorry but to me  there's only one likely outcome after all this dust settles, is it any coincidence that seasonal models have flipped to mild & Zonal just as the output has started to go downhill? I don't think so.

 

there really is no connection between seasonal models output and trying to compare to either 4x daily synoptic or even some longer term links.

[radiohead]

Quick update. UKMO have elected to run with their GM unmodified at T+84 due to better continuity/consensus. More on the ramifications around this tomorrow when I get a chance.

 

Very interesting... Thanks Fergie.

[johnholmes]

Poor long term from 18z GFS http://images.meteociel.fr/im/4449/gfs-0-300_ige5.pngRe Mogreps Ian F often gives us updates when we are on the cusp of a cold spell. If Not on here then on twitter. I don't put much faith in the fax's 99.9% of the time they are identical to the UKMO raw output and chop and change with every run. Btw A few Meto folks were tweeting earlier that they didn't buy the UKMO as it was more extreme than any other model and too far west with the front on weds

 

That is a bit of an odd remark I feel. The Fax chart is NOT solely based on any one product but on the assessment by the senior man at Exeter on his whole suite of charts from a variety of sources. It is often weighted to the outputs from Exeter fairly obviously but other inputs are used. But as new data comes in so the Fax chart will alter. Be a bit daft if it did not?

 

see the comment I've just noticed from Ian above about accepting this evening their own GM at T+84 over any other. Another assessment by the senior man with everying in front of him that a particular output looks the most feasible.

 

a very good example of a change with later data is the Fax issued for 12z Wed last evening compared to the one issued this evening?

Hard to be much different but highly probable to be nearer the mark, hence the change.

http://www.weathercharts.org/ukmomslp.htm#t120

 

the charts will change as new ones come out using this link so you need to be quick to see what I'm posting about

Edited November 16, 2013 by johnholmes

[LomondSnowstorm]

That is a bit of an odd remark I feel. The Fax chart is NOT solely based on any one product but on the assessment by the senior man at Exeter on his whole suite of charts from a variety of sources. It is often weighted to the outputs from Exeter fairly obviously but other inputs are used. But as new data comes in so the Fax chart will alter. Be a bit daft if it did not?

 

see the comment I've just noticed from Ian above about accepting this evening their own GM at T+84 over any other. Another assessment by the senior man with everying in front of him that a particular output looks the most feasible.

Last night being a prime example when the senior forecaster went against the GM's take on proceedings at +96 instead going with a heavily modified solution (I realise that's the wrong chart now because the faxes have updated but take a look anyway, the long awaited new +96):

 

The reason they mostly look like the GM is, I'd imagine, because model agreement is usually pretty reasonable up to +120 at least to the point where modifications aren't that noticeable. A few times during similar 'high Shannon entropy' events last winter they did modify their faxes pretty heavily from the GM.

Edited November 16, 2013 by LomondSnowstorm

[The Post-modern Winter]

That is a bit of an odd remark I feel. The Fax chart is NOT solely based on any one product but on the assessment by the senior man at Exeter on his whole suite of charts from a variety of sources. It is often weighted to the outputs from Exeter fairly obviously but other inputs are used. But as new data comes in so the Fax chart will alter. Be a bit daft if it did not? see the comment I've just noticed from Ian above about accepting this evening their own GM at T+84 over any other. Another assessment by the senior man with everying in front of him that a particular output looks the most feasible.

That is a bit of an odd remark I feel. The Fax chart is NOT solely based on any one product but on the assessment by the senior man at Exeter on his whole suite of charts from a variety of sources. It is often weighted to the outputs from Exeter fairly obviously but other inputs are used. But as new data comes in so the Fax chart will alter. Be a bit daft if it did not? see the comment I've just noticed from Ian above about accepting this evening their own GM at T+84 over any other. Another assessment by the senior man with everying in front of him that a particular output looks the most feasible.

John, I think you often try to provide rational, educated answers or responses to irrational, emotion-led statements. Admirable but must leave you banging your head against the wall.

[bluearmy]

Well the T 96 is modified from raw ukmo. Its further east and a half way house with ecm op.

[LomondSnowstorm]

Anyway, the new +96 fax is a beauty (as expected given the forewarning by Ian):

With the 528dam line straddling the centre of the country and cold air coming back at us from the north behind the shortwave this creates the risk of perhaps disruptive (if transient) snowfall for inland eastern areas and higher ground in particular. A forecaster's nightmare if ever there was one!

Edited November 16, 2013 by LomondSnowstorm

[The Northern Ramper]

Well the T 96 is modified from raw ukmo. Its further east and a half way house with ecm op.

But not un modified up to t84, suggesting this is FI.

[johnholmes]

John, I think you often try to provide rational, educated answers or responses to irrational, emotion-led statements. Admirable but must leave you banging your head against the wall.

 

sometimes I admit a bit like that but I just post as I see it having tried to assess it objectively. I get it wrong for sure at times, no forecaster never makes mistakes. Just smile, admit it, explain why and move on. Leave any successes for others to notice. From professional experience it is fairly quickly noticed. That is not meant for on Net Wx but in my previous life!

Well the T 96 is modified from raw ukmo. Its further east and a half way house with ecm op.

 

by raw ukmo do you mean their GM model?

[bluearmy]

Yes john - raw ukmo is ukmo gm

[johnholmes]

Anyway, the new +96 fax is a beauty (as expected given the forewarning by Ian):

 

With the 528dam line straddling the centre of the country and cold air coming back at us from the north behind the shortwave this creates the risk of perhaps disruptive (if transient) snowfall for inland eastern areas and higher ground in particular. A forecaster's nightmare if ever there was one!

 

Yes the degree of change from trough to fully fledged low suggests some fairly large changes around that time scale. Being the senior man will be interesting over the next 2-3 days as they try and decide just how this feature will play out.

hopefully it will not create too many tantrums in here as it is bound to change as the models from the various centres try to get the correct handle on it. An interesting spell and well worth watching and learning from it in my view.

[swfc]

sometimes I admit a bit like that but I just post as I see it having tried to assess it objectively. I get it wrong for sure at times, no forecaster never makes mistakes. Just smile, admit it, explain why and move on. Leave any successes for others to notice. From professional experience it is fairly quickly noticed. That is not meant for on Net Wx but in my previous life!

 

by raw ukmo do you mean their GM model?

Quick one here.why is the fax chart skipping the 84 hrs on its update?noticed this a few times.thanks.Also what is gm?

Edited November 16, 2013 by swfc

[radiohead]

Well the T 96 is modified from raw ukmo. Its further east and a half way house with ecm op.

 

The position of the low is slightly further northeast, but overall it looks very similar to the GM to me.

[johnholmes]

Quick one here.why is the fax chart skipping the 84 hrs on its update?noticed this a few times.thanks

 

I am unable to answer that swfc, drop them an  e mail and ask if they can explain why?

[Frosty.]

Well here we are again with cold upgrades and longevity, coldies are finally rewarded for their patience following a generally warmer than average and benign autumn..things are about to change big time with much colder arctic air surging south early next week, tonights Ecm 12z ens mean / ukmo 12z are currently showing us the most likely outlook. :- )

[zubzero]

Quick one here.why is the fax chart skipping the 84 hrs on its update?noticed this a few times.thanks.Also what is gm?

 

There is only a 84z chart in the morning for some reson

[Captain Shortwave]

T120 FAX chart

Atlantic shortwave has cut through the ridge. Good news. Hopefully the other models will move towards the UKMO tomorrow.

[bluearmy]

Gm = global model

There has never been a publically issued fax T84 from the 12z run.

And the modification made from the gm at t96 makes all the difference as far as possible snowfall is concerned. Its almost as if the main man has placed it just far enough east that no snowfall is likely. Tbh, for the sanity of most in here, thats probably a good thing!

[Frosty.]

As expected, the Ecm 12z op is binned and the outlook is better again for those who prefer cold frosty weather with a risk of snow to a 3000 miles long draw sw'ly. We are on the cusp of a dramatic pattern change to wintry weather..hooray.

[Nick L]

Folks, can we get back on topic please? Cheers.

 

Also, one liners making a vague reference to the models doesn't add to the discussion.

Edited November 17, 2013 by Nick L

[Panayiotis]

Ive seen that no one has interest in the 72hr fax....I wonder why? As it does show a trough moving down the BI within the 528dam line which could produce a few surprises!

[swfc]

Having seen the 120hr fax chart where does that leave ecm and gfs?

Edited November 17, 2013 by swfc

[Barry12]

Having seen the 120hr fax chart where does that leave ecm and gfs??given the human input to the fax you woudnt think there would be any change in the other output"ecm ,gfs" or am i reading it wrong?

The FAX is backing the UKMO, not the GFS/ECM.

[swfc]

The FAX is backing the UKMO, not the GFS/ECM.

yes i no.what i mean is where does it leave thegfs and ecm regarding there model output on todays runs!

Edited November 17, 2013 by swfc

[swfc]

oz  better and trending towards the ukmo.Makes a real feature of the low sliding down the east of the uk from 60hrs plus.slightly more amplified at 144 hrs but starts to drop south east at 168 hrs and sits over uk.As you were ie 18z at 180 so in the short term its an upgrade be it slight.Then its a rampant pv over greenland

Edited November 17, 2013 by swfc