Model Output Discussion 17th Dec.2013-12z onwards.

[weather eater]

Well the 12z GFS some more building block signs but as I suspected only transient colder interludes and unfortunately a lot more rain. 

[Summer Sun]

Latest NAO update keeps it around neutral during the first couple of weeks of January

 

 

The latest AO update keeps it negative albeit with lots of scatter

 

Edited December 28, 2013 by Summer Sun

[ARNOTT ad]

What an incredibly uninspiring winter this year! Can you just believe it, and at our latitude too.

[ANYWEATHER]

What an incredibly uninspiring winter this year! Can you just believe it, and at our latitude too.

Im afraid this is normal default weather really, although the storms have stepped up a gear this year to give us the stormiest December for a good many years. But if you have in the weather history books ,you will see there is nothing unusual about our weather at the moment. Plenty of time for Winter weather which normally arrives after Christmas rather than before.....

[karyo]

Latest NAO update keeps it around natural during the first couple of weeks of January

 

 

 

 

 

 

I guess you mean neutral.

 

Horrible UKMO by the way!

 

Karyo

[karyo]

Im afraid this is normal default weather really, although the storms have stepped up a gear this year to give us the stormiest December for a good many years. But if you have in the weather history books ,you will see there is nothing unusual about our weather at the moment. Plenty of time for Winter weather which normally arrives after Christmas rather than before.....

Yes, but normally we would get a northerly toppler or two even in the mildest of winters!

 

This winter we have a constant westerly/southwesterly.

[Cecil Hogmanay Melchett]

Yes, but normally we would get a northerly toppler or two even in the mildest of winters!

 

This winter we have a constant westerly/southwesterly.

UKMO is disappointing tonight.

I was hoping for better.

Certainly little sign of that rampant Atlantic slowing down,surely to God there must be no juice left in the tank!!

Edited December 28, 2013 by Cecil Hogmanay Melchett

[Summer Sun]

More of the same from UKMO with wind and rain continuing next week, and with pressure building to our east  these lows will take longer to clear

 

[stratty]

Yes, but normally we would get a northerly toppler or two even in the mildest of winters!

 

This winter we have a constant westerly/southwesterly.

 

...........maybe this is the New even larger teapot, after the Old even larger teapot of the noughties and the Neo even larger teapot of the last few years?

[BLAST FROM THE PAST]

Worth IMO keeping eye on alternative methods, stormy new Year and chance of real cold blast/s in Jan have been the idea for some considerable time irrespective of poor strat reports.......all I say is give it a chance as confidence remains high...and models are only beginning to add to the confidence.  They haven't got it right yet as the pattern ahead is very volatile.

 

 

BFTP

Edited December 28, 2013 by BLAST FROM THE PAST

[Methuselah]

Worth IMO keeping eye on alternative methods, stormy new Year and chance of real cold blast/s in Jan have been the idea for some considerable time irrespective of poor strat reports.......all I say is give it a chance as confidence remains high...and models are only beginning to add to the confidence.  They haven't got it right yet as the pattern ahead is very volatile.

 

 

BFTP

I do prefer the scientific methods, Fred...Much better over the past years, IMO...

[Tamara]

As part of the gradual pattern changing process we have unfolding, its worth keeping an eye on the Pacific ridge and its return to an Aleutian poleward position as we go through the opening 10 to 15 day period of January. For face value purposes the ECM shows it here at day 10 - although the timing is opening to question, even if the evolution of the eventual pattern on background evidence is looking increasingly feasible.

 

We can see clearly how the pattern is buckling and amplifying with the jet energy starting to show signs of splitting upstream with an Aleutian High/ US trough and also westward retrogressing Azores High in the making. As hinted at in some of the far FI ensemble data

 

This is all part and parcel of the change of jet stream axis from SW-NE to NW-SE that Chiono ilustrated as the precursor to the split energy to follow that will then in turn assist the retrogression of any Siberian High later in the month

 

As stated, its questionable of the timing of this sort of chart, but the ridge into the pole provides a further tropospheric wave activity element of attack on the vortex alongside a further (reasonably anticipated) Asian MT event later in January to lead to an increase of our chances of getting a more significantly cold pattern backed towards the UK from the east thereafter.

[weather eater]

I do prefer the scientific methods, Fred...Much better over the past years, IMO...

I prefer to put my finger in my mouth and make a popping noise, it’s like the butterfly effect only with fingers, the pop goes around the world and hey presto an easterly turns up a week later. 

[Timmytour]

The story of the GFS 12z is rain rain rain and unrelenting rain for much of England at least and New  Years Day looks horrific!There's no obvious route to cold from it, but if it materialises, many will be too washed out to wish for anything other than a dry southerly/southwesterly flow for a few weeks after!. 

[karyo]

UKMO is disappointing tonight.

I was hoping for better.

Certainly little sign of that rampant Atlantic slowing down,surely to God there must be no juice left in the tank!!

Well, the tank is the cold stratosphere and it appears to be full! 

[Frosty.]

I think we are on track for a gradually colder outlook with a higher risk of wintry ppn than we have seen so far this winter..which is not saying much I know, even this mediocre gfs 12z op run has cold weather with wintry ppn at times, very little in the way of mild weather. I think we are going to see the jet gradually digging further south with the jet axis tilting northwest / southeast with increasing trough disruption and colder incursions becoming more pronounced as time goes on, the week ahead again looks disturbed with gales and heavy rain with a risk of further flooding, next saturday looks cold, very cold in the north before the next vigorous low arrives, barely any breathing space between each atlantic low..no sign of anything settled whatsoever apart from brief flat ridging.

Edited December 28, 2013 by Frosty.

[Ali1977]

Is it me or are the Ens showing much more cold potential this run, at 276 anyway???

Actually think it's me.....I'm seeing things I think

Edited December 28, 2013 by Ali1977

[Summer Sun]

Wednesday has the potential for further flooding in places

 

[IDO]

The GEM is OK if you acknowledge that D1-10 will remain cyclonic:  

 

A potential good profile for a colder flow. The GFS op was an outlier and by T240 much better NH profiles for the ensembles:

 

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=6&ech=240

 

Again the control is sort of in the ball-park as to the most recent output, T240:

 

 T300:  T360: 

 

Getting cooler then colder. It had less defined Polar heights than some of the ens, but was not sending the thrust of them to W.Canada, like the op.

Edited December 28, 2013 by i'm dreaming of...

[Ali1977]

GFS control run.....awesome cold/snow FI

[johnholmes]

As part of the gradual pattern changing process we have unfolding, its worth keeping an eye on the Pacific ridge and its return to an Aleutian poleward position as we go through the opening 10 to 15 day period of January. For face value purposes the ECM shows it here at day 10 - although the timing is opening to question, even if the evolution of the eventual pattern on background evidence is looking increasingly feasible.

 

We can see clearly how the pattern is buckling and amplifying with the jet energy starting to show signs of splitting upstream with an Aleutian High/ US trough and also westward retrogressing Azores High in the making. As hinted at in some of the far FI ensemble data

 

This is all part and parcel of the change of jet stream axis from SW-NE to NW-SE that Chiono ilustrated as the precursor to the split energy to follow that will then in turn assist the retrogression of any Siberian High later in the month

 

As stated, its questionable of the timing of this sort of chart, but the ridge into the pole provides a further tropospheric wave activity element of attack on the vortex alongside a further (reasonably anticipated) Asian MT event later in January to lead to an increase of our chances of getting a more significantly cold pattern backed towards the UK from the east thereafter.

 

 

I am not convinced that the upper ridge has to be in the area you suggest Tamara. In none of the 500mb charts I have looked at in the past 20-30 minutes for December 2009, January 2010 or December 2010 was that the case. There was an upper trough in the eastern Pacific and an upper ridge over the western coast of North America.

hopefully see one example below=sorry will not allow it, I'll try again

~$0mb chart 1 jan 2010.doc

not sure if anyone will be able to see this?

As to how much effect this pattern then had downstream with another marked ridge showing in the Greenland/Iceland area I cannot remember without looking in detail at the huge data files I keep of anomaly charts. This in turn gave a cold flow north of west over the Uk and the subsequent continuation of wintry weather?

it looks as if it will not open up, sorry about that

Edited December 28, 2013 by johnholmes

[SMU]

Afternoon All-

 

Weather is all about timing & speed of movement.

 

Have you often wondered why one solution presents itself in the models for maybe 4/5 days on the trot - maybe a Northerly or a deep depression heading for the UK, then suddenly its gone-

Almost every single example of change or disparity between the models is due to SPEED & OR Timing & phasing of systems.

 

Take tonight-

 

The 12z GFS is MILD in the outlook - but its all to do with timing & interaction. Critically the 12z is very fast with the low coming out of the states @ 144 - its over cooking the depth-

 

Heres 144-

http://modeles.meteociel.fr/modeles/gfs/runs/2013122812/gfsnh-0-144.png?12 -  Because of the speed & angle it phases together with the energy over southern Greenland-

http://modeles.meteociel.fr/modeles/gfs/runs/2013122812/gfsnh-0-192.png?12 -  Note how we now have another super system powering east-- with a flat jet..

 

Remember timing is everything.

 

Now take the control - same time.

Heres 144-

http://modeles.meteociel.fr/modeles/gens/run/gensnh-0-1-144.png?12  - Note - the system is shallow & sliding off the coast earlier-

& 192

http://modeles.meteociel.fr/modeles/gens/run/gensnh-0-1-192.png?12 - The system is NOT phasing with the main low & swinging underneath - the jet is kinked now SE ahead of it but NE behind it- creating that wedge of high pressure allowing a slower evolution & blocking to the NE to take control.

 

NET:http://modeles.meteociel.fr/modeles/gens/run/gensnh-0-1-336.png?12

 

Now look at the GEM & UKMO

 

GEM

http://modeles.meteociel.fr/modeles/gem/runs/2013122812/gemnh-0-144.png?12 Shows the system almost as far north as the GFS but slower with a wedge of high pressure ahead of it stopping the phasing of these 2 lows

 

NET:http://modeles.meteociel.fr/modeles/gem/runs/2013122812/gemnh-0-240.png?12

Note the UKMO is more or less the same as the GEM at 144.

 

So people if your looking for COLD- we want to slow that pacific jet down or better still get that low pressure from not phasing with that Icelandic low.

 

 

Finally the ensemble means continue to grow the influence the Kumchatka high has across the pole

http://modeles.meteociel.fr/modeles/gens/run/gensnh-21-1-276.png?12

 

 

Cheers

 

S 

[Gael_Force]

I am not convinced that the upper ridge has to be in the area you suggest Tamara. In none of the 500mb charts I have looked at in the past 20-30 minutes for December 2009, January 2010 or December 2010 was that the case. There was an upper trough in the eastern Pacific and an upper ridge over the western coast of North America.

hopefully see one example below=sorry will not allow it, I'll try again

~$0mb chart 1 jan 2010.doc

not sure if anyone will be able to see this?

As to how much effect this pattern then had downstream with another marked ridge showing in the Greenland/Iceland area I cannot remember without looking in detail at the huge data files I keep of anomaly charts. This in turn gave a cold flow north of west over the Uk and the subsequent continuation of wintry weather?

it looks as if it will not open up, sorry about that

 

Is this what you are trying to show?

 

[Duane S.]

The models are driving me insane, easterly, no easterly. Now you see it, now you don't, northern blocking. Mild, then cold, wait it's mild again. Give it five days and then one model might start agreeing with another, instead of them having a constant, mass brawl. I need a lie down.

 

I assume you are new to all this then? Trust me, the past few weeks are really nothing in terms of inconsistent model output. There has been no real strong signal yet to a direct route to cold. Yet. There are plenty of positives that simply weren't there 3 weeks ago however and it will be from this that the building blocks to a proper (not transient) cold spell will be built upon. Only once we get the first credible signal to real cold show up on the charts and start to edge closer will you see the forum rollercoaster in full on action. Not a place for the faint hearted!

[cooling climate]

As part of the gradual pattern changing process we have unfolding, its worth keeping an eye on the Pacific ridge and its return to an Aleutian poleward position as we go through the opening 10 to 15 day period of January. For face value purposes the ECM shows it here at day 10 - although the timing is opening to question, even if the evolution of the eventual pattern on background evidence is looking increasingly feasible.

 

We can see clearly how the pattern is buckling and amplifying with the jet energy starting to show signs of splitting upstream with an Aleutian High/ US trough and also westward retrogressing Azores High in the making. As hinted at in some of the far FI ensemble data

 

This is all part and parcel of the change of jet stream axis from SW-NE to NW-SE that Chiono ilustrated as the precursor to the split energy to follow that will then in turn assist the retrogression of any Siberian High later in the month

 

As stated, its questionable of the timing of this sort of chart, but the ridge into the pole provides a further tropospheric wave activity element of attack on the vortex alongside a further (reasonably anticipated) Asian MT event later in January to lead to an increase of our chances of getting a more significantly cold pattern backed towards the UK from the east thereafter.

Unless you have the amplification with an Aleutian ridge to push heights into the Arctic which would

probably have happened with a weaker vortex all it does is send Arctic outbreaks south across the

midwest and northeast America.

I would favor something more akin to what the 12z GFS control is showing following on from a

fairly strong Asian MT within the next week or two. The MT is predicted on the back of recent

tropical forcing although this could manifest itself in a stronger West coast American ridge or

Aleutian ridge.