Model Output Discussion 26/10 2012 >

[SMU]

Hi Steve

The scandi Ridge on the ECM t 144 is quickly shunted east by the end of the run, can we expect this to not be the case and the block will hold

firm and maybe even migrate to Iceland ?

Shotski

Its way to fast through- so yes the block will slow it all down....

All seasons- its a nice thought- however that amount of energy wont move under the block,- as it moves closer the system will get sheared & eventually extend SE inthe form of smaller shortwaves-

S

[phil nw.]

Some Eastern promise in the 12z runs again with the T144- 168hrs onwards creating interest.

Later frames favour low pressure still close to the UK but those heights to the ne not far away.

http://www.wetterzen...cs/Recm1921.gif

http://www.wetterzen...s/Rtavn1921.png

We may need a bit of time for such an evolution to affect the UK.One way for this would a be cutoff UK trough sinking south allowing those heights to regress to our north.

Such as above- from the 12z GEF`s .

Edited November 4, 2012 by phil n.warks.

[Allseasons-Si]

Its way to fast through- so yes the block will slow it all down....

All seasons- its a nice thought- however that amount of energy wont move under the block,- as it moves closer the system will get sheared & eventually extend SE inthe form of smaller shortwaves-

S

Thanks steve for the reply,i know it's out to 240hrs,but could it become a cut off low,i see a ridge developing up into greenland on this run,could it join with scandi hp,just a thought.

[chionomaniac]

Its way to fast through- so yes the block will slow it all down....

All seasons- its a nice thought- however that amount of energy wont move under the block,- as it moves closer the system will get sheared & eventually extend SE inthe form of smaller shortwaves-

S

Steve, are there any examples of historic November retrogressing Scandi highs?

My suspicions are that there will be too much energy pushing this east, however, the next wave will enter up into Greenland. Here we will see local wave breaking into the stratosphere - possibly just in time to halt the descending increasing zonal winds from the upper levels.

If that does occur then from there we will see enough continued strat disruption to lead us into early winter.

[shotski]

Its way to fast through- so yes the block will slow it all down....

All seasons- its a nice thought- however that amount of energy wont move under the block,- as it moves closer the system will get sheared & eventually extend SE inthe form of smaller shortwaves-

S

Thanks Steve. well spotted on this one, you have been talking about this now for a good few day

[SMU]

I think the ECM is way to far east- & there will be a lot of movement west, where we end up is a guess, as usual this little country is the end of the line, so borderline for us-

I dont really remember many retrogressions in Nov- remember mid Nov you are going against the core of the vortex over Southern greenland to get retrogression out of Scandi-

The GFS does it- the ECm is there at 168 but then loads the dice-

I will have a lookski-

S

Edited November 4, 2012 by Steve Murr

[chionomaniac]

I think the ECM is way to far east- & there will be a lot of movement west, where we end up is a guess, as usual this little country is the end of the line, so borderline for us-

I dont really many retrogressions in Nov- remember mid Nov you are going against the core of the vortex over Southern greenland to get retrogression out of Scandi-

The GFS does it- the ECm is there at 168 but then loads the dice-

I will have a lookski-

S

And that I think could be critical because no matter how far west the initial block starts, I suspect that it will get pushed east from the start. But no worries if the vortex disruption pattern continues, because as that door shuts another will open.

[SMU]

Maybe this Winter

http://modeles.meteociel.fr/modeles/reana/1878/archivesnh-1878-11-20-0-0.png

http://modeles.meteociel.fr/modeles/reana/1878/archivesnh-1878-11-26-0-0.png

http://modeles.meteociel.fr/modeles/reana/1878/archivesnh-1878-11-30-0-0.png

S

[Allseasons-Si]

And that I think could be critical because no matter how far west the initial block starts, I suspect that it will get pushed east from the start. But no worries if the vortex disruption pattern continues, because as that door shuts another will open.

I take it that you are talking about amplification chio,something we didn't see much of last winter.

[chionomaniac]

Maybe this Winter

http://modeles.meteo...8-11-20-0-0.png

http://modeles.meteo...8-11-26-0-0.png

http://modeles.meteo...8-11-30-0-0.png

S

Ha - a good try but I suspect that that is a new wave in the days in between!!! Just another 134 years to go through then......

Edited November 4, 2012 by chionomaniac

[lorenzo]

GEM is worth a look tonight, not sure what it does with the 00z to 12z with meteo showing it cut off at 144 on the 12z, storming jet pattern and to use the best term of the day 'loaded' or if you want it without a ramp 'poised'.

What a change from yesterday, didn't expect the models to dispatch/dilute the NAO / AO peaks so quickly..has been a great day of watching.

[lorenzo]

1878 Steve ?? How on earth did you dig that out - are you Derren Brown?

[Mark Neal.]

1878 Steve ?? How on earth did you dig that out - are you Derren Brown?

How an earth did he know of that time, don't say you have been trawling through every year looking for something like that

Interesting times ahead and once again a good time to be model watching, a whole different complex this time last year. Still very early days but encouraging once again the key word.

[Frosty.]

Maybe this Winter

http://modeles.meteo...8-11-20-0-0.png

http://modeles.meteo...8-11-26-0-0.png

http://modeles.meteo...8-11-30-0-0.png

S

Maybe we can bring snowatch back

I like the way the models are shaping up beyond the next 5 days, I wish we could fast forward to mid/late november and see a stonking easterly from siberia about to sweep into the uk, it will be very interesting to see how the models handle this unique situation for so early in the season.

[bluearmy]

GEM is worth a look tonight, not sure what it does with the 00z to 12z with meteo showing it cut off at 144 on the 12z, storming jet pattern and to use the best term of the day 'loaded' or if you want it without a ramp 'poised'.

What a change from yesterday, didn't expect the models to dispatch/dilute the NAO / AO peaks so quickly..has been a great day of watching.

gem 12z only runs to T144 Lorenzo.

[A.J]

How an earth did he know of that time, don't say you have been trawling through every year looking for something like that

Interesting times ahead and once again a good time to be model watching, a whole different complex this time last year. Still very early days but encouraging once again the key word.

A solid post Mark, and to be frank members need to take heed of the highlighted quote before getting to carried away and jumping on the ramp express for synoptics that may or may not happen. Trends, as the more learned have posted on, are becoming cryptically apparent, but that is all they are currently

[Methuselah]

If you follow the daily sequence starting 19 November 1985, the Scandi High re-locates towards Greenland.

http://www.wetterzentrale.de/archive/ra/1985/Rrea00119851119.gif

[shotski]

Are we saying that a retrogressing scandi high in November are as rare as Tits on a chicken.

Edited November 4, 2012 by shotski

[Pixel]

_{http://www.meteociel...H1-144.GIF?04-0}

_{This again proves if you know what the model bias is in EVERY scenario you can forecast the model output before it even comes along....}

_S

Hi Steve.. I've been a lurker on here many years but I never thought you were a ramper.. maybe you have seen something all the abreviatives have missed? I'm liking your thoughts as I envisage winter to kick off in the last week of November just based on some of the graphical interpretations of the jet and it's wobble these last few weeks. But I really know nothing !

Please indulge a mere mortal such as myself as to what bias you have seen... cos mine is just a hunch.

[chionomaniac]

If you follow the daily sequence starting 19 November 1985, the Scandi High re-locates towards Greenland.

http://www.wetterzen...00119851119.gif

Probably one of the few examples. Give the man a gold star!

Are we saying that a retrogressing scandi high in November are as rare as Tits on a chicken.

Something along those lines, yes!

[Fozfoster]

Are we saying that a retrogressing scandi high in November are as rare as Tits on a chicken.

Or even hens teeth!!

[SMU]

One for the newer PPL viewing... ( & FOR PIXEL )

So why a Scandi block at 144 on the Euros & not the I'm not happy, in fact I'm quite sad model-

Its all about small changes in the way the model is interpreting the speed & Vector of the jet-

Remember the jet stream will be moving West East at X speed M/S- once you start slowing it down it will start recurving to the North or to the south-

If you take away say 2 or 3 M/S out the jet speed then the recurve is gentle like a boomerang shape-, if you take another 3M/s out the same jet then it would have been a sharper recurve to the North or South-

The ECM & UKMO at T84/96- 120 take the energy distribution & weaken the easterly vector by probably a few M/S more than the GFS ( remember the GFS doesnt resolve Scandi blocks well)- so the GFS in essence has a bias of to much energy going east in the flow, as it gets a better grip on the block so you erode the easterly movement & the jet recurves sharper & sharper-

The net is seeing a model move the Scandi High west the Nearer we get to T=0- although what are you are seeing is it getting closer to the truth with each run.

Heres your classic GFS example of to much northern energy-

All we are talking is a few M/S over estimated-

Anyway 12z GFS 96 & 120 chart-

What you are looking for if you want to see a ridge thrown north to Scandi out of the Atlantic area is an area of warm air advection moving North - Alongside an area of Cold air advection moving South-

IYou will only get the ridge if there is essentially no close phasing of the jet- So if you take the 12z GFS the atlantic arm is alligned NE & taking that WAA build towards the area of cold air moving South-

Eventually that tiny window of opportunity highlighted in pink at 96 has shrunk & has been cut off from the atlantic- essentially as soon as that happens you will have energy 'over the top' & the scandi high cannot build in situ.

now look at the UKMO-

It would first appear they are the same & broadly they are at 96, however UKMO is slower & more amplified, with the WAA pulse going directly North thus allowing that ridge from the atlantic what it needs to build & remain in situ-

At 120 we have a solid gap between WAA & CAA to hold the ridge long enough to build- circa 1030 Mb-

Its all about speed - the slower the better.

For Future outputs look at this timeline & the advection- you want it to tilt like this NOT the North eastward tilt on the GFS

PS the GFS bias of loading up the northern arm is why it doesnt look like the UKMO....

Its fast by maybe 5 M/S in its estimations...

S

Edited November 4, 2012 by Steve Murr

[Grimsby Snow Lover]

Or even hens teeth!!

Sorry mods, couldn't resist

Edited November 4, 2012 by Grimsby Snow Lover

[Rocheydub]

Terrific post SteveM. Just terrific. I have learned so much from that, thank you!

[ribster]

One for the newer PPL viewing... ( & FOR PIXEL )

S

Yep, excellent post thanks Steve, explaining why and how you think things will evolve. Should be clear to both seasoned and newer members to the forum.