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

[Mr Frost]

There seems to be a lot of hunting for cold, claims of patterns changes etc. the reality is more of the same.Eventually , of course , there will be a pattern change but some people might have been calling for a pattern change for weeks by then. What huge change does occur does that mean kudos for people constantly talking of change/ cold.The posters I follow closely are fergieweather and Martin Gibbs; impartial with no bias. Any profile that has any mention of cold in profile title/ name should be treated with caution lol

Kev...it is Winter. Of course people are hunting cold. As in April when 99% of people are hunting for warmth.A pattern change will come - as it always does. Most folk are currently giving reasons and evidence to back up those claims of a pattern change arriving mid/ late January. It looks as though something is about to give as per the current thoughts in the strat thread and the Metoffice update. This thread is no different to Summer with regards to people hunting for weather they wish to see. Frosty (Karl) has been getting stick for posting cold charts everyday from a few who prefer mild weather...he does the same in Summer except posts hot charts - yet I don't see the same people giving him stick then? It is all very bizarre really. Hopefully those who prefer Seasonal weather will get there fix of snow and frost - still plenty of time for that. I can think of nothing worse than a Winter of constant wind, rain and above average temperatures. Same as I can think of nothing worse than a Summer of endless rain, cloud and average/below average temperatures. Don't forget...Wintry weather can always bite in March. :-)

[Cecil Hogmanay Melchett]

Patience is still the buzzword.The GFS06Z is a truly nauseating run with HP across Southern Europe proving just as annoying as the PV over Greenland!

[lassie23]

Any sign of northern blocking on any models today?

[Mucka]

There seems to be a lot of hunting for cold, claims of patterns changes etc. the reality is more of the same.

Eventually , of course , there will be a pattern change but some people might have been calling for a pattern change for weeks by then. What huge change does occur does that mean kudos for people constantly talking of change/ cold.

The posters I follow closely are fergieweather and Martin Gibbs; impartial with no bias. Any profile that has any mention of cold in profile title/ name should be treated with caution lol

 

Depends. A lot of people project their own feelings onto what is actually being said.

Yes, there is always the search for blocking and cold and so there will be many false dawns but that doesn't mean the output is being interpreted incorrectly. If a signal is there it is there,whether it comes to fruition is another thing entirely.

Where you are correct is that most coldies (including me) will concentrate on the more positive aspects for cold in the output while the mild camp or doom-mongers will generally concentrate on the negatives - human nature I'm afraid.

Then there are those who interpret the posts that analyse the charts and project their own positive or negative views onto them.

For example, nobody has said a cold spell is imminent.

What you describe as claims of change are reality, it is just a matter of having wider perspective.

 

I'm getting  a head of steam up now and oh, here's my soap box!

I say this on behalf of all the excellent posters who search for cold patterns and put a lot more skill and information into any speculation than me but I will speak from my personal perspective.

 

When you say people talking pattern change will eventually be correct then that is a little disingenuous of you and belittles the effort many excellent posters put into their analysis and even their speculation as to how things might unfold.

 

On 17th Dec I stated this.

"In the longer term there is a weak signal for height rises to our East as we head toward New Year"

 

On the 18th I posted this;

"I don't make forecasts but I would argue that there is no reason to expect January to continue as December ends as the jet likely sinks South giving the chance of troughing into Europe and increased amplification of the pattern"

 

You might argue that the first half of January is looking the same as the second half of December but I think I could make a pretty convincing argument otherwise.

Given we were in the midst of an Atlantic onslaught with no end in sight at the time that was pretty decent call but I'm also a coldie and I also wrote this;

"I wouldn't be surprised if we are looking at a potential cold spell as early as the second week "

That looks unlikely but note I don't say cold spell in second week, I say looking at a potential cold spell (ie the pattern is setting up in the second week)

 

On Dec 20th I said this when continuing my idea that conditions would be more favourable for blocking come January.

 

"..Now this doesn't mean HLB and a strong cold signal should appear in the same timeframe and I wouldn't expect ECM ensembles to show anything other than Ian F describes (describing EC32 showing zonal westerly flow out toward end of January) because within the 15 day timeframe any blocking is very unlikely to establish itself to the extent of bringing a cold spell and even decent blocking that is forming within those ensembles may well show a Westerly flow and moderate or even mild temperatures. Forget ECM32, or at least take its long range output with a pinch of salt, it is just going with the favourite instead of looking at the form guide.

The fact is there will be a window of opportunity for blocking to grab a foothold as the jet moves South with low pressure moving into Central Europe out to the mid term and what is considered reasonable reliable timeframe of the output (around 144) at the same time we have pressure rising on the other side of the pole"

 

Nowhere in the posts do I call a cold blocked first half of January, I only talk in general terms of the possibility of a pattern change and what it may mean and TBH a fair bit of effort goes into so it does grate a little when people just post off the cuff remarks undermining it all. Yes I do it for my own pleasure but I also try to help and inform where I can even with my limited knowledge and abilities.

You are welcome to only read posts that give you the information without any speculation or going outside of T120 but why take a swipe at those that try to be informative, elaborate upon the patterns we see and where they might lead and God forbid have a little fun from time to time by speculating on cold.

I get things wrong all the time but I'm still learning from many of the great posters here because they take the time to explain what charts mean and what we want to see to see things develop in a certain way. I'm not afraid to speculate on the output because it is generally accepted that forecasting beyond day 5 is a tricky business and thank fully I don't have each and every wrong call rammed down my throat. That is what makes this forum so popular and addictive reading, the variety of posts and inclusiveness rather than exclusiveness.

 

Ahem, I really am becoming an old crank myself. 

 

Edited December 29, 2013 by Mucka

[Gaz1985]

No real change in the 6z Manchester ens compared to yesterday - looking wet for the foreseeable, a miserable 7-14 days with temperatures near average.

 

[Davey80]

Any sign of northern blocking on any models today?

No

[cooling climate]

Something to remember is that  downwelling  in a +QBO regime is generally quicker than

during a -QBO. Jan 2009 is a good example plus the warming occurred in a similar area.

I think what we are likely to see in the extended range model output over the coming days

is for pressure to rise over eastern north America and the western Atlantic and the

troughing to be turning more nw/se with pressure remaining high over nw Russia.

Then as blocking becomes more prevelent to the north (Jan 17th onwards) we are likely

to see trough disruption and undercutting  as the russian block moves west.

[Cecil Hogmanay Melchett]

No real change in the 6z Manchester ens compared to yesterday - looking wet for the foreseeable, a miserable 7-14 days with temperatures near average.

 

That's a poor set of ensembles.Taking us to pretty much half way through January Without so much as a snowflake round here.

Of course we have seen ensembles flip before now but you would be very surprised to see snow before the 10th of Jan at the EARLIEST based on that set of ensembles.

Crewe colds confidence of January matching Dec 2010 for cold looks a tad, ambitious ....

[Tamara]

There seems to be a lot of hunting for cold, claims of patterns changes etc. the reality is more of the same.

Eventually , of course , there will be a pattern change but some people might have been calling for a pattern change for weeks by then. What huge change does occur does that mean kudos for people constantly talking of change/ cold.

The posters I follow closely are fergieweather and Martin Gibbs; impartial with no bias. Any profile that has any mention of cold in profile title/ name should be treated with caution lol

The process of separating personal weather preference from objective model output discussion is quite straightforward if one's aim is to give as accurate a suggestion as they can/are able to as a worthy contribution to the overall topic.

 

This really brings us to the here and now - and a very interesting situation we have setting up for January with the predicted activity on the polar vortex and suggestions of *some* degree of demise (the greater we hope) later in January. This is a slow burner - but that provides plenty of interest time to see how events unfold while the atlantic rages on for a while longer. Sometimes patience, which isn't always seen at large on this thread, can really produce the rewards.

 

Especially when it is designed to meet both hopes and preferences YET remain objective and realistic at the same time

 

As suggested the other day - this trough disruption pattern will prove slower than some of the modelling might suggest/have suggested at times, and it is really best to try and take a longer view wrt the significant colder pattern prospects. In the meantime, the Canadian vortex is discharging another bundle of pent up energy our way as more Tundra-esque air escapes into the atlantic and meets warm moist air of tropical atlantic origin.  It is the product of another sequence of these lows that will be making the headlines this week once again for all the wrong reasons.

 

In theory as the Canadian lobe discharges itself more fully and low pressure systems become cut off features from the main vortex then this *should* limit the extremes of cyclogenesis as the gradient weakens. Rain thus increasingly becoming the main hazard rather than wind - but that on its own is more than enough as so many areas of the country are already reeling from the effects of the recent severe storms

Edited December 29, 2013 by Tamara תָּמָר

[bobbydog]

Patience is still the buzzword.The GFS06Z is a truly nauseating run with HP across Southern Europe proving just as annoying as the PV over Greenland!

 

a little misleading maybe, those factors alone do not dictate the weather to come, nor are they necessarily negative factors.

the azores high is another "annoying" example of a 'negative factor'

 

take a look at these examples-

 

 

azores high with a strong PV over greenland.

 

or this-

 

 

big euro high with again, a strong PV over greenland.

 

firstly note the dates of those charts

 

 

in both examples, within 2 weeks, winter hit the UK with a vengeance.

 

also note the fact that the PV is split into 2 main parts- as we are experiencing now.

we also have a strat warming forecast.

 

we may not see anything materialize until the end of january but if it does, and (let's say) lasts for the whole of february, then the memory of the previous 2 months will be lost in a flurry of snow......

[pdiddy]

We can all see ens showing a "rinse and repeat" pattern of low/ridge/low for the next week at least, and probably slightly longer. 

Tightly grouped and a few degrees milder than the norm for Aberdeen at least.

 

http://www.wetterzentrale.de/pics/MT8_Aberdeen_ens.png

 

For those arguing that there are no signs of change, the MetO seem to differ:

"Some signs are also emerging suggesting temperatures being less mild in general terms than the last couple of weeks, and perhaps even significantly colder late in the month."

 

This is an interesting call given the safe option is to predict more of the same... 

Edited December 29, 2013 by pdiddy

[Isabellesnanny]

Gardeners Question Time on radio today was in association with Met Office and Met Office stance seemed to be that the signs and data for this winter pointed to less severe than the last couple of years - assume they have a lot more stats and information than is available to general public but wonder if their thoughts will be realised.

[Captain Shortwave]

Nice old GFS consistency

Previous run

A lot of difference over the pole, especially at just 3 days away 

Will it effect the mid-range of this run though,

[Snowman.]

Much stronger polar heights here.

 

 

Compared to here.

 

Edited December 29, 2013 by SN0WM4N

[Mucka]

The process of separating personal weather preference from objective model output discussion is quite straightforward if one's aim is to give as accurate a suggestion as they can/are able to as a worthy contribution to the overall topic.

 

This really brings us to the here and now - and a very interesting situation we have setting up for January with the predicted activity on the polar vortex and suggestions of *some* degree of demise (the greater we hope) later in January. This is a slow burner - but that provides plenty of interest time to see how events unfold while the atlantic rages on for a while longer. Sometimes patience, which isn't always seen at large on this thread, can really produce the rewards.

 

Especially when it is designed to meet both hopes and preferences YET remain objective and realistic at the same time

 

As suggested the other day - this trough disruption pattern will prove slower than some of the modelling might suggest/have suggested at times, and it is really best to try and take a longer view wrt the significant colder pattern prospects. In the meantime, the Canadian vortex is discharging another bundle of pent up energy our way as more Tundra-esque air escapes into the atlantic and meets warm moist air of tropical atlantic origin.  It is the product of another sequence of these lows that will be making the headlines this week once again for all the wrong reasons.

 

In theory as the Canadian lobe discharges itself more fully and low pressure systems become cut off features from the main vortex then this *should* limit the extremes of cyclogenesis as the gradient weakens. Rain thus increasingly becoming the main hazard rather than wind - but that on its own is more than enough as so many areas of the country are already reeling from the effects of the recent severe storms

 

I pretty much agree with this other than the assertion that trough disruption will prove slower than being modelled. As far I am concerned this sis till up for grabs and there is plenty of chopping changing within the models as to how much trough disruption there will be when those next "bundles" of vortex energy are pealed off around days 5 but more especially day 7/8.

Lately the trend has been to weaken the Scandinavian ridge and push more energy NE (thus less disruption) but I don't believe this is a done deal. No matter we will see more wet and windy weather, if not the very severe gales we have seen through the second half of December, and flooding will of course be an issue but the relevance of how this period is modelled will only become apparent later in the charts, specifically how much trough disruption we get in the second week of January as the Atlantic quietens and how strong and close the Siberian high is come mid Jan will be largely dependant on this.

The long term implications aren't too dramatic, the way I see it, it is not a choice between zonal or blocked, just a choice between colder zonal toward mid Jan with a more favourable pattern setting up to take quicker advantage of the longer term stratospheric forecasts and hemispheric pattern predictions.

 

I'm not saying this mornings ECM is closer to reality than the flatter, faster GFS but I think it has a little more running time before conclusions can be made about blocking only having a chance to take hold very late January or early February. The possibility of an earlier progression exists and let's not forget back in mid  December most of the talk based on strat projections were of a flat zonal  first half to January at least if not longer while the ensembles were suggesting the possibility of weak blocking forming and Southerly jet which has turned out to be the reality.

 

GFS12z out to 120h is flatter still to the East but the Arctic high is much more prominent than the last run so still a fair bit to be decided even if the current GFS trend is for a weaker ridge and  less trough disruption in the mid term

 

 

UKMO also still showing less disruption and more storminess.

 

Edited December 29, 2013 by Mucka

[Captain Shortwave]

Well a much better profile over Canada with some amplification compared to the flat as a pancake 06z. I wonder if after ditching the Russian ridge, it will decide to build a decent ridge in the West Atlantic.

With the Siberian vortex lobe stretching into Svalbard then there is a decent shot at a Scandi/Euro trough too developing in the latter stages. 

This shows promise

Atlantic trough moves east with Atlantic ridge pushing north, if it meets with the Pacific ridge then you have your 5 day plus cold spell. Epic FI coming up???

Edit - FI.....WTF GFS 

Edited December 29, 2013 by Captain shortwave

[Jonan92]

Quite interesting, big improvement

 

[Panayiotis]

Hmm whats happening in the Atlantic!?

[If Wishes made Weather]

Well this is interesting - note the large area of high pressure off the Canadian coast.  With luck this will stop the relentless west-east movement of systems.

 

[That ECM]

http://images.meteociel.fr/im/7180/gfsnh-5-180_okh7.png

The heights on this run showing out west have effect of slowing the jet which in turn could slow the procession of lows towards us. Would like to see more runs show this.

^^^^^^^ I agree.

Edited December 29, 2013 by That ECM

[Mucka]

Well a much better profile over Canada with some amplification compared to the flat as a pancake 06z. I wonder if after ditching the Russian ridge, it will decide to build a decent ridge in the West Atlantic.

With the Siberian vortex lobe stretching into Svalbard then there is a decent shot at a Scandi/Euro trough too developing in the latter stages. 

This shows promise

 

 

I'm sure Steve M will have noted the Kumchatka  ridge (convention) joining up with Arctic high at least.

 

 

If the Scandi ridge was stronger and the trough further West we would have had more amplification behind as the Azores high wouldn't of been able to ridge back in so quickly. IFS and BUTS.

[Bobby]

Well this is interesting - note the large area of high pressure off the Canadian coast.  With luck this will stop the relentless west-east movement of systems.

 

 

Computer says no, more zonal than the 06z

 

 

A very wet week or so coming up especially in the West, 4-5+ inches of rain in places, more flooding concerns

 

Edited December 29, 2013 by Bobby

[Panayiotis]

Well the GFS temporary Atlantic ridge scenario is interesting because the 00z ECM, GEM, CMA, CFS 1 Month (to an extent) and the CFS 9 Month (to an extent) all show a similar scenario at 240hrs...

Will be interesting to see if they continue this new trend...

 

PS I am aware that the ECM picked this up yesterday, showed by its ensemble mean >> http://forum.netweather.tv/topic/78787-model-output-discussion-17th-dec2013-12z-onwards/?view=findpost&p=2878019

Edited December 29, 2013 by Panayiotis

[ITSY]

on the plus side, look at the stratospheric profile come the end of low res:

[Cloud 10]

Computer says no, more zonal than the 06z

 

 

 

Stratosphere says yes,still showing the Greenland (ish) warming.

 

 

 

Very much agree regarding the flooding though.