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Model Output Discussions 06z 04/11/16

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1 minute ago, karlos1983 said:

Quite simply, when we are looking at building blocks for a cold pattern, the last thing we want to throw in is an ex hurricane. IMO. Can change everything. 

Otto looks to be heading to the Pacific... so don't think there will be a direct impact on any Atlantic driven cold spell. Perhaps some second order impacts on jet to West of US?

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Just now, pdiddy said:

Otto looks to be heading to the Pacific... so don't think there will be a direct impact on any Atlantic driven cold spell. Perhaps some second order impacts on jet to West of US?

Unsure, I'm really only talking about Atlantic Basin Hurricanes that head North toward Greenland and or Iceland/UK. It's just a variable I think we could do without!

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1 hour ago, Ed Stone said:

I wonder what Tokyo's 1963 winter was like?

Don't know- but I know what ours was like! :cold:

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Whilst the coldest weather is currently across scotland with freezing fog and sharp frosts, the coldest weather gradually transfers south as the high sinks slowly southwards next week with widespread frosts and some freezing fog under high pressure while the nw / n uk becomes more mobile with spells of wind and rain but cold enough at times for sleet and snow on hills and occasionally to lower ground and then later next week even the south becomes unsettled too..

From around mid December it becomes more settled / blocked with height rises to the n / ne of the uk with predominantly fine conditions across most of the uk with a southerly tracking jet bringing occasional unsettled intervals with a risk of snow on high ground, especially in the north and frequent frosts with some freezing fog...very seasonal, rather a cold period with temps below average more often than not!..bit of a change from last Dec then:D

Edited by Frosty.

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2 minutes ago, Gavin Hannah said:

Expect that outlook to change if the GFS / GEM continue their train of thought and the ECM backs away. :drunk-emoji:

Rather you *want* that to happen...we've been here so many times. @Weathizard typically they are right, only when it goes wrong it unfairly stands out. Dec is not far off, however likely does not stress certainty but nor does it deviate from from what they're expecting, I seriously doubt the 'experts' even trawl through GFS, amongst more high calibre MOGREPS and what else they have.8)

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Just now, Changing Skies said:

Rather you *want* that to happen...we've been here so many times. @Weathizard typically they are right, only when it goes wrong it unfairly stands out. Dec is not far off, however likely does not stress certainty but nor does it deviate from from what they're expecting, I seriously doubt the 'experts' even trawl through GFS, amongst more high calibre MOGREPS and what else they have.8)

You are probably right, but I have a good feeling about this ... :D

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1 hour ago, Tamara said:

 

At the risk of appearing 'boring' - its the same caution watchword from me as per the last couple of weeks.  Its well known that tropical convective modelling is especially unreliable generally across the models beyond about 5 days. On that basis I don't think we can apportion a 'correct' solution here - its very much a watching brief.

That said ( and is the case at all times) intra-seasonal and re-cyclical timeline factors are principle assets in attempting to eschew when/how tropical and extra tropical phenomena might evolve, and in turn influence NWP solutions.  Its on that basis that intuitive guidance, as being applied on these pages, is certainly reasonable and highly valuable in terms of suggesting another return to the tropical signal in the Maritimes - the rinse and repeat forcing that has frame-worked the wider weather patterns since the later part of the summer. It is very much the return to this signal, that would boost atmospheric angular momentum and augment the process for amplification and higher latitude height rises in tandem with an unstable vortex. 

However, the precise timing of this, in my opinion, is actually becoming increasingly important for that those looking for seasonal cold and white stuff (which naturally includes myself) and will want it to occur in very close symmetry with maximum stratospheric destabilisation. A downside risk evolves according to any degree of 'failure' here.

In this respect, there cannot be excess delay to the tropical signal, and there cannot afford to be any further shortfall in stratospheric weakness forecasts..  So whilst the latest ECM suite (s)may currently appear 'wrong' ( after all, it isn't showing what people like) it remains very wise to acknowledge that it is a (provisional) warning of what can happen if the types of shortfall mentioned verify.

Whilst a favourable stand-off has existed between weak Nina ocean and atmospheric circulation signal, the trend heading into winter (desirably for those wanting cold) is one where the atmospheric circulation is best one of angular momentum inching higher within the parameters allowed by ENSO, not just to capitalise on early stratospheric weakness, but to bolster longer term amplification feedbacks that encompass Eurasian snow cover albedo.

2012 has already been cited as a good example in a recent post where froth and fervour to greet the winter season turned to fast frustration when seemingly 'little could go wrong' in the model world.  It did come right from Jan 2013, but it was a virtuous +AAM cycle, as driven by amplifying tropical and extra tropical phenomenon alongside stratospheric weakness related to SIA that enabled this. ...It was also a stutter in this cycle that initially scuppered it...

Delays and shortfalls - then the hallowed Pacific Ridge will not sustain as a poleward feature (as part of a cross-polar ridge pattern for sympathetic downstream higher latitude height rises) and will entail a typical Pacific winter Nina like pattern at mid latitudes with early winter reliance on some cold zonality and brief arctic topplers before, potentially, the Atlantic jet increasingly flattens out as maximum stratospheric weakness is not utilised and seasonal wavelengths lengthen further to couple the Annular mode 'unfavourably'.

Its to be emphasised here that this is a low risk scenario at present.

However, if traction increases to consolidate an eastwards signal in the tropics as consensus modelling, there are continued signs to show that the Pacific favours a ENSO neutral with a +AAM tinge (a winter such as 78/79 is a good parallel here) then stratospheric weakness will be utilised with the Pacific ridge very much a friend in terms of being part of a cross polar stratospheric induced ridge - that is the beginning of a period for snow and ice.

The latter constitutes a deliberate ramp, but you get the picture. The former represents something less exciting - but whatever the models, the professional consensus etc may suggest - it cannot (yet) be dismissed.

 

As if the excitement from the model output wasn't enough we get a post from Tamara. Always a pleasure to read. 

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9 minutes ago, Changing Skies said:

Rather you *want* that to happen...we've been here so many times. @Weathizard typically they are right, only when it goes wrong it unfairly stands out. Dec is not far off, however likely does not stress certainty but nor does it deviate from from what they're expecting, I seriously doubt the 'experts' even trawl through GFS, amongst more high calibre MOGREPS and what else they have.8)

If by experts we mean the met office then they are being quite bullish about it getting cool and trending colder. Apologies for off topic mods but I think this should be pointed out. Current outlook for 29 Nov to 8 December says " It will stay generally cold so frost will be fairly widespread. In the first few days of December, wet and windy conditions are likely to spread across the whole country, especially in the north. The rain may turn to sleet or snow over high ground, and possibly even to lower levels at times in the north. Temperatures are expected to be around, or perhaps a little below, normal."

Then 9 Dec to 23 December "After a wet and windy start to this period, high pressure is likely to dominate from mid December, especially in the north and east... It is likely to be rather a cold period, with temperatures below average for the time of year."

Seems pretty bullish to me coming from the understandably cautious meto.

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1 hour ago, terrier said:

Personally I think on tonight's output we will see the gfs12z move towards the ecm evolution. The ecm will then move towards the gfs06z output. And as we get nearer the time we will see a half way house situation between the output.

A genuine question for anyone to answer. If, as has been widely claimed, the difference between the ECM and GFS evolutions is largely down to whether a low phases (ECM) or not (GFS) with the main trough near Greenland, can we really end up with a 'half way house situation'? In such a binary choice like that, with large downstream effects, I'm not sure we can, although weather is inherently 'complicated' so maybe we can.

In any case, I'd think that the last two 6z GFS solutions (don't forget yesterdays run caused some excitement too) are likely to be at the extreme end of the cold spectrum.

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36 minutes ago, bobbydog said:

Don't know- but I know what ours was like! :cold:

I was looking at some old Weather reports and it was cold with blizzards, notably in western Japan, where snowdrifts of 12 ft..    Are the stars aligned this year for us.:)

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21 minutes ago, Nouska said:

Looks like they saw a similar cold anomaly in January - holy grail synoptics.

T 850bbabc7dc11624220e3aa26d1a690cf8c.gif    Z500  psnh_mon_hist_z500_196301.gif

Strong wave 2, pre SSW split, in evidence there.

Page 8 of interest ...similar pattern to this year for December ?

Cold frosty start to December ,milder middle part of December......

 

https://www.rmets.org/sites/default/files/abstracts/Mar/16032013-burt.pdf

Edited by FetchCB

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Fascinating stuff again.Heart says Gfs, head says Ecm.As someone who has been a weather enthusiast for a long time i have learned some painful lessons- personally im expecting Gfs12z to look pretty much nothing like 6z, what i dont want to see on the 12zs is anything rrsembling the 0z Ecm because that was everything i do not want to see as a landing point for December.As a fully paid member of the cold brigade im obviously hoping for a u-turn from Ecm, or at least a move away from that 0Z run this evening but if i were a betting man id be putting money down on the ecm being nearer the mark...

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1 hour ago, Seasonality said:

If by experts we mean the met office then they are being quite bullish about it getting cool and trending colder. Apologies for off topic mods but I think this should be pointed out. Current outlook for 29 Nov to 8 December says " It will stay generally cold so frost will be fairly widespread. In the first few days of December, wet and windy conditions are likely to spread across the whole country, especially in the north. The rain may turn to sleet or snow over high ground, and possibly even to lower levels at times in the north. Temperatures are expected to be around, or perhaps a little below, normal."

Then 9 Dec to 23 December "After a wet and windy start to this period, high pressure is likely to dominate from mid December, especially in the north and east... It is likely to be rather a cold period, with temperatures below average for the time of year."

Seems pretty bullish to me coming from the understandably cautious meto.

However, it is worth bearing in mind that these are based on model outputs and analysis to provide an indication of possible outcomes against normal climatology. Being the chaotic beast that meteorology is, if a new unexpected signal is picked up, or development occurs, this can potentially change surface conditions for the UK quite substantially. I think this is why people often criticise these longer range text forecasts for being "wrong", when in-fact it is just as liable to change. I do have confidence in their forecasts, but it is easy to over-analyse these.

This page is useful for defining and interpreting their various forecasts, whether it is 1-2 days ahead or 3 months... http://www.metoffice.gov.uk/services/public-sector/contingency-planners 

 

Edited by Chris K

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6 minutes ago, northwestsnow said:

Fascinating stuff again.Heart says Gfs, head says Ecm.As someone who has been a weather enthusiast for a long time i have learned some painful lessons- personally im expecting Gfs12z to look pretty much nothing like 6z, what i dont want to see on the 12zs is anything rrsembling the 0z Ecm because that was everything i do not want to see as a landing point for December.As a fully paid member of the cold brigade im obviously hoping for a u-turn from Ecm, or at least a move away from that 0Z run this evening but if i were a betting man id be putting money down on the ecm being nearer the mark...

Head say's a middle ground between the two.

Meto says wet & windy start to December, that leaves the door open (in my mind) to a stormy first have which could be cold or mild????

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Just a reminder,  this is the first time the new upgraded GFS is being tested for this winter, it became available 14th January of this year. So comparisons between the current GFS and other models might not be valid if youre basing it on the fact that the old GFS has certain faults.... 

Edited by Panayiotis

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Just now, Ed Stone said:

Here it comes, the 12Z we've all been waiting for...Is Snowmageddon incoming or not?:yahoo:

Of course it is.... faith you must have.... :drunk-emoji:

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So buckle in guys and girls here comes the gfs12z. Will we see a shift towards the ecm.? If I had to place a bet my money would be a shift towards the ecm from this morning. But if it does head towards the ecm let's remember we still have a long way to go this winter. 

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Just now, abbie123 said:

So here we go gfs and later ecm I'm going for gfs behind sofa time...

Funny you should say that...isn't today the 53rd anniversary of the first ever :yahoo:episode of Dr Who?

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11 minutes ago, Seasonality said:

Holding steady out to 18h!!!

 

 

 

gfs-0-18.png

Forgive me as I am a novice but isn't that chart bad for cold?

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