Model Output Discussion 1st January 2014-06z onwards.

[Summer Sun]

Just about as you were for today's NAO update slightly negative for a short time before heading back to neutral

 

 

Today's AO update heads positive for a time later this week and early next week before going negative once more around mid month

 

[shaky]

Just about as you were for today's NAO update slightly negative for a short time before heading back to neutral

 

 

Today's AO update heads positive for a time later this week and early next week before going negative once more around mid month

 

much better update ao wise!!looked like it was gona go positive couple of days ago!!nao not too bad either!!hopefully all of this will start to show up on the models later!!

[draztik]

Looking at the available data this morning, I think the most favourable route is for heights to build to our NE for a time! I am still of the thinking that it will be a battle ground over the UK - with the Atlantic winning! But obviously, it depends on where the HP system sits. Further west, and we could see the treasure the majority in here seek!

Ecm ens t144

Thereafter, looking at gefs suite, heights to our NE lose their influence, and with troughing centered over the UK, and with ridging in the Atlantic, indicates a westerly/northW, which will obviously bring temps below average for the UK, tho staying unsettled. Snow possible further North and on higher ground.

gefs mean t276

After that, the signal is for troughing to take hold to our NW, but with a negative anomaly into Europe even by day 16, and the jet continuing to dig south, temps will remain below average. (that signal is more evident from gefs)

Gefs mean t384 & ecm ext t360

Temp anomaly indicates this, with below average for UK/western Europe, but nothing akin to very below (that's reserved for Scandinavia) tho mild it will not be!

Surface temp anomaly day 11-16

Edited January 7, 2014 by draztik

[Man With Beard]

Looking at the available data this morning, I think the most favourable route is for heights to build to our NE for a time! I am still of the thinking that it will be a battle ground over the UK - with the Atlantic winning! But obviously, it depends on where the HP system sits. Further west, and we could see the treasure the majority in here seek!

Ecm ens t144

Thereafter, looking at gefs suite, heights to our NE lose their influence, and with troughing centered over the UK, and with ridging in the Atlantic, indicates a westerly/northW, which will obviously bring temps below average for the UK, tho staying unsettled. Snow possible further North and on higher ground.

gefs mean t276

After that, the signal is for troughing to take hold to our NW, but with a negative anomaly into Europe even by day 16, and the jet continuing to dig south, temps will remain below average. (that signal is more evident from gefs)

Gefs mean t384 & ecm ext t360

Temp anomaly indicates this, with below average for UK/western Europe, but nothing akin to very below (that's reserved for Scandinavia) tho mild it will not be!

Surface temp anomaly day 11-16

That's a really useful analysis, Draztik. The thing I notice from this (and from Glenn W above) is that heights are forecast to be subdued over central/southern Europe, which is one precursor of a cold spell.

 

I think Bluearmy's post is very relevant to any long-term analysis, though. Trying to pin anything down past 10 days atm is a bit of a lottery. The models will be doing well if they get the first pattern change right, let alone a second change!! Things have got to be really stable to put much confidence in things such as ECM32 right now, I feel. Of course, sometimes they will be right, but if anyone remembers just last year between mid-January and mid-March, over and over again, the 10 day+ forecasts wanted to banish cold from the UK - over and over again, the cold kept coming back. 

[Tamara]

Whilst the medium to longer term has high uncertainties with respect to pattern change timings, there is a definite de-powering of the polar vortex imminent which signifies it has very probably passed its seasonal peak as assisted by wave activity action which looks to permit a modest build of heights to our NE in the short and medium term.

 

This is just the very start of, in model output terms, a gradual and quite likely erratic transitional period from the intensely gradient fuelled westerlies of recent weeks to a slow decleration of the atlantic train that on balance imo probably won't allow enough blocking potential in the 10 to 15 day period to provide the UK with its first significant cold spell of the winter. Always nice to be proved wrong though

 

However, within this time, there is a very much higher chance of cold pooling setting up further east and north into Europe which may well supply the longer term interest late in the month and more especially as we get into February. Changes in seasonal wavelengths allied with further anticipated and stronger wave activity ever weakening the vortex through a much more damaging blow next time around - these being the mechanism for this to occur imo later in January and hopefully make the last third or so of winter a much more enjoyable experience.

 

The pattern thus far, alas, has followed previous realistic expectations of the winter being vortex dominated for December and at least a fair amount of January too, and such a prognosis as suggested above would further underline the seasonal evolutional probablilties of cold incursion potential being loaded towards the last third of the winter.

 

We have to expect further unwanted rainfall to come on the basis of westerly jet stream energy retaining, on balance, probably too much strength for effective trough disruption realistically into the medium term to back NE European cold pooling far enough west for us.

 

However, chances increase as the month progresses for the queue of troughing being ejected from the eastern seaboard of the UK to slow progress across the atlantic and provide further favourable warm air advection poleward to assist sustaining (and increasing the westward influencing effectiveness) of the programmed modest heights towards Scandinavia.

 

In this way the further wave breaking mechanisms are perpetuated towards plotting the eventual demise of a very resistant and seasonally controlling vortex that should increase the UK chances towards a cold spell.

 

Patience. Not a new word to the 2013/14 winter time dictionary..

[Cecil Hogmanay Melchett]

Whilst the medium to longer term has high uncertainties with respect to pattern change timings, there is a definite de-powering of the polar vortex imminent which signifies it has very probably passed its seasonal peak as assisted by wave activity action which looks to permit a modest build of heights to our NE in the short and medium term.

 

This is just the very start of, in model output terms, a gradual and quite likely erratic transitional period from the intensely gradient fuelled westerlies of recent weeks to a slow decleration of the atlantic train that on balance imo probably won't allow enough blocking potential in the 10 to 15 day period to provide the UK with its first significant cold spell of the winter. Always nice to be proved wrong though

 

However, within this time, there is a very much higher chance of cold pooling setting up further east and north into Europe which may well supply the longer term interest late in the month and more especially as we get into February. Changes in seasonal wavelengths allied with further anticipated and stronger wave activity ever weakening the vortex through a much more damaging blow next time around - these being the mechanism for this to occur imo later in January and hopefully make the last third or so of winter a much more enjoyable experience.

 

The pattern thus far, alas, has followed previous realistic expectations of the winter being vortex dominated for December and at least a fair amount of January too, and such a prognosis as suggested above would further underline the seasonal evolutional probablilties of cold incursion potential being loaded towards the last third of the winter.

 

We have to expect further unwanted rainfall to come on the basis of westerly jet stream energy retaining, on balance, probably too much strength for effective trough disruption realistically into the medium term to back NE European cold pooling far enough west for us.

 

However, chances increase as the month progresses for the queue of troughing being ejected from the eastern seaboard of the UK to slow progress across the atlantic and provide further favourable warm air advection poleward to assist sustaining (and increasing the westward influencing effectiveness) of the programmed modest heights towards Scandinavia.

 

In this way the further wave breaking mechanisms are perpetuated towards plotting the eventual demise of a very resistant and seasonally controlling vortex that should increase the UK chances towards a cold spell.

 

Patience. Not a new word to the 2013/14 winter time dictionary..

I can think of one or two others T

Shalom.

[nick sussex]

Well here goes......!!got a bad bad feeling about this one!!love to be proved wrong though!!

The GME at T72hrs is very nice and the NAM shows a bit of interest at T84hrs. I haven't seen anything in terms of the latest data pre GFS 12hrs run to need the Prozac helpline. Of course though the GFS today has pulled out two different scenarios, bad 00hrs run and good 06hrs in terms of trend. So its really the big 3 that count this evening.

Edited January 7, 2014 by nick sussex

[Paul]

For those who prefer to banter about the models rather than discuss them in more detail, don't forget there is the model chat/banter/moans/ramps thread:

 

http://forum.netweather.tv/topic/78680-model-banter-moans-and-ramps-winter-201314/

 

Typical posts suited to that thread may be:

 

 

I don't like this run, no snow for [enter place]

or

 

I have a bad feeling about this, nothing to do with the models just gut instinct

or

 

I know every model is showing [enter weather type], but I don't believe them I have a feeling it'll be [enter opposite weather type]

or

 

I hate these models, when will they show snow?

or

 

Woohoo!!!!! Finally it's going to get cold/hot/wet/dry

[winterof79]

Whilst the medium to longer term has high uncertainties with respect to pattern change timings, there is a definite de-powering of the polar vortex imminent which signifies it has very probably passed its seasonal peak as assisted by wave activity action which looks to permit a modest build of heights to our NE in the short and medium term.

 

This is just the very start of, in model output terms, a gradual and quite likely erratic transitional period from the intensely gradient fuelled westerlies of recent weeks to a slow decleration of the atlantic train that on balance imo probably won't allow enough blocking potential in the 10 to 15 day period to provide the UK with its first significant cold spell of the winter. Always nice to be proved wrong though

 

However, within this time, there is a very much higher chance of cold pooling setting up further east and north into Europe which may well supply the longer term interest late in the month and more especially as we get into February. Changes in seasonal wavelengths allied with further anticipated and stronger wave activity ever weakening the vortex through a much more damaging blow next time around - these being the mechanism for this to occur imo later in January and hopefully make the last third or so of winter a much more enjoyable experience.

 

The pattern thus far, alas, has followed previous realistic expectations of the winter being vortex dominated for December and at least a fair amount of January too, and such a prognosis as suggested above would further underline the seasonal evolutional probablilties of cold incursion potential being loaded towards the last third of the winter.

 

We have to expect further unwanted rainfall to come on the basis of westerly jet stream energy retaining, on balance, probably too much strength for effective trough disruption realistically into the medium term to back NE European cold pooling far enough west for us.

 

However, chances increase as the month progresses for the queue of troughing being ejected from the eastern seaboard of the UK to slow progress across the atlantic and provide further favourable warm air advection poleward to assist sustaining (and increasing the westward influencing effectiveness) of the programmed modest heights towards Scandinavia.

 

In this way the further wave breaking mechanisms are perpetuated towards plotting the eventual demise of a very resistant and seasonally controlling vortex that should increase the UK chances towards a cold spell.

 

Patience. Not a new word to the 2013/14 winter time dictionary..

Good well reasoned post Tamara.The METO are also hinting of a gradual cool down and colder weather patterns to emerge in to early Feb.

Not to say we will not get a few snow events before then as heights lower to the south of us at times.

http://modeles.meteociel.fr/modeles/gfs/runs/2014010706/gfsnh-0-192.png?6

We must remember that even though we have been spoiled over the past few winters,rarely have we had more than one month of proper cold within those.We still have two left or maybe three if last March is anything to go by.

Edited January 7, 2014 by winterof79

[shaky]

The GME at T72hrs is very nice and the NAM shows a bit of interest at T84hrs. I haven't seen anything in terms of the latest data pre GFS 12hrs run to need the Prozac helpline. Of course though the GFS today has pulled out two different scenarios, bad 00hrs run and good 06hrs in terms of trend. So its really the big 3 that count this evening.

has the NAM improved on its 06z earlier on and carried on from its improved amplification!!

[nick sussex]

has the NAM improved on its 06z earlier on and carried on from its improved amplification!!

Its better in terms of the jet to the west of the UK but anyway who needs the NAM, enjoy the GFS! it looks nice so far.

[Weather Boy]

If someone offered me a negative tilt trough  further to the west and even more amplification over the ne USA I will happily put my last pound on a  cold outcome for the UK. So I think you can see how important that is!

 

We are getting to the point now where we should start to see the models come together to at least decide on the upstream pattern as the key detail is really quite close.

 

We're into the T96hrs range where that amplified wave starts to move across towards the ne USA so really we should hope for agreement on that tonight. Theres still room for more amplification or less, its on a knife edge.

 

Hi Nick

 

Can you please let us know what you mean by negative and positve tilt, something I have pondered for a while now.

 

I imagine that what you are saying is a low shaped/tilted with the northern part towards the west (thus making it more likely to go north overall as it progresses west), whereas a negative tilt is the opposite, with the southern part more advanced than the northern, thus making it more likely to dive towards mainland Europe when it approaches.  Neutral would essentially be a blob with no particular tilt either way.

 

Is that what you mean?

 

Surely the tilt could change as it crosses the Atlantic, in which case, how important is the tilt when it is over the US?

 

Keep up the good work, btw!

Edited January 7, 2014 by Weather Boy

[MR EXTREMES]

nice gfs up to t108 if a little suspect but if correct could well build a lot of confidence on something wintry futher down the line.

 

to be fair its a reasonable evolution from the gfs model.

good to see lower heights bringing cold into Europe.

 

brick wall as steve murr mentioned a yesterday.

Edited January 7, 2014 by emotional rollercoaster

[nick sussex]

Hi Nick

 

Can you please let us know what you mean by negative and positve tilt, something I have pondered for a while now.

 

I imagine that what you are saying is a low shaped/tilted with the northern part towards the west (thus making it more likely to go north overall as it progresses west), whereas a negative tilt is the opposite, with the southern part more advanced than the northern, thus making it more likely to dive towards mainland Europe when it approaches.  Neutral would essentially be a blob with no particular tilt either way.

 

Is that what you mean?

 

Surely the tilt could change as it crosses the Atlantic, in which case, how important is the tilt when it is over the US?

 

Keep up the good work, btw!

Okay negative running more nw/se, neutral north/south and positive ne/sw the tilt is crucial neutral at worst to stop energy running ne , if its negative the energy shears away to the nw and neutral more north, as you can see here I would have been putting my pounds down on a wager but theres a troublesome shortwave to the north that needs to take a hike.

 

The troughing that's important is the one to the west of the UK that's where the tilt is crucial.

 

More about the shortwave later, in the middle of making my dinner!lol

Edited January 7, 2014 by nick sussex

[warrenb]

One negative tilt to order, coming right up Sir

[MR EXTREMES]

Okay negative running more nw/se, neutral north/south and positive ne/sw the tilt is crucial neutral at worst to stop energy running ne , if its negative the energy shears away to the nw and neutral more north, as you can see here I would have been putting my pounds down on a wager but theres a troublesome shortwave to the north that needs to take a hike.

 

The troughing that's important is the one to the west of the UK that's where the tilt is crucial.

 

More about the shortwave later, in the middle of making my dinner!lol

yes as I posted the t120 comes out and it looks like early on the gfs flattens the pattern although the expected changes are beyond this point.

yes as I posted the t120 comes out and it looks like early on the gfs flattens the pattern although the expected changes are beyond this point.

will the azores high be friend or foe Im thinking the later.

[Sunny Kent]

I hope this is not a daft question, but the GFS 12Z 850mb/sea level run suggests a rapid decline of the cold that has been parked over Canada and the north US for ages. Is this significant?

[Cecil Hogmanay Melchett]

Another GFS,another improvement in the overall pattern.

Atlantic systems  disrupted by High pressure cells across the GIN.

FINALLY winter starts across much of Northern and central Europe at 144.

Edited January 7, 2014 by Cecil Hogmanay Melchett

[warrenb]

Yes but the GFS just can't bring itself to lower heights over Europe, so the lows have nowhere to go

[MR EXTREMES]

thats how things are prog, at present however I think by latter this week things may look a whole lot more chilly? :

id like to add this I noticed them charts by summer sun im a little confused when the models are showing this

but summer charts show this

[mountain shadow]

I hope this is not a daft question, but the GFS 12Z 850mb/sea level run suggests a rapid decline of the cold that has been parked over Canada and the north US for ages. Is this significant?

Any little helps.

 

The Atlantic jet has been driven across the pond by the deep Canadian cold and the relatively warmer waters of the Atlantic. The less cold it is in North America, the lesser the temperature gradient between Eastern Canada and the Western Atlantic, the less strong will be the jet.

[Cecil Hogmanay Melchett]

Yes but the GFS just can't bring itself to lower heights over Europe, so the lows have nowhere to go

Looks an improvement to my eyes Warren and low pressure is getting established into Europe at 150h.

[MR EXTREMES]

yes indeed this is a much better run by the gfs neg tilted and phasing with the second low pressure in the alantic more of a south east movement perhaps of the low pressure.

 

funny the mention of the cold in the usa I was reading a blog on my weather app earlier and there has been talk of things improving over there.

Edited January 7, 2014 by emotional rollercoaster

[Nick L]

id like to add this I noticed them charts by summer sun im a little confused when the models are showing this

but summer charts show this

 

What specifically confuses you? The 2nd chart is the anomaly chart (the difference from normal, not the actual temperature) if that helps?

[R.P. McMurphy]

id like to add this I noticed them charts by summer sun im a little confused when the models are showing this

but summer charts show this

 

One is the 850's and the second is the 2m surface.

Edited January 7, 2014 by Glenn W