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Model Output Discussion - 10th Jan Onwards


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proper pony run from the 18z there tbh.Ridging to the north east just not robust enough and no support for it to the south ie low pressurePosted Image What happend to the days when we got a few good northerlies in winter?getting very tedious now this winterPosted Image

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Not a bad chart at 180, perhaps this is the run that stops the rot?  Upgrades for the next two days then bingo!

 

Posted Image

 

Computer says no. It does look likely the Atlantic will fire up again around day 10+ onwards, has been the theme for a while on the NWP, however hopefully some surprises still lurk somewhere.

 

Posted Image  Posted Image

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Not a bad chart at 180, perhaps this is the run that stops the rot?  Upgrades for the next two days then bingo!

 

Posted Image

Well, quite. I did make the comment that there is plenty of time for change. It's not like December 2012 when the models suddenly spluttered a T+48; we are talking about the better part of a week away.

Not saying that we'll have a frigid easterly next weekend, but as has been said ad nauseum, the models find this kind of situation v. Difficult at a much closer range than this and so fairly significant changes are likely over the weekend and beyond.

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What we would also like to see is the Scandi trough completely phase with this incoming wave from the Atlantic. This should help heights to the North possibly retrogress. Heres hoping. We also need to see those heights lower more in the med, having them too high for any phasing of the jet in the med will be another chink in the armour. Surely we will see something this winter!!

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Just looking at the ECM charts predictions and we can see where the road to the easterly suddenly hit a landmine, the negative tilt troughing was replaced by a more neutral at the critical timeframe, once again the reluctance of shortwave energy to clear se allowed the tilt to change.

 

Lets bear in mind the ECM prediction was only at T96hrs, a timeframe when you think the models would resolve shortwave issues to the north.

 

The upstream pattern was well modelled by the ECM and the pattern to the east but the area around Iceland again has proven to be full of landmines!

 

Indeed we see across the models this inability to deal with that area when it comes to this type of set up, overall the models are moving to a consensus with the broader pattern but still however some uncertainty in terms of the detail over the UK , because of the continued displacement of the Azores high and troughing near the UK  and the block still in evidence I would be surprised if we don't see more easterlies modelled, the orientation of the PV stretched sw/ne to the nw is closely correlated with high pressure running in that same direction near the UK.

 

 

 

 

 

 

 

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Why do we NEED a stratospheric warming? Other parts of the northern hemisphere do just fine without one. Genuine question. 

Edited by PerfectStorm
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Interesting to see Steve's interpretation of the effect of the Norway shortwave on the shape and subsequent development of the Scandi high. Seems there is a mesoscale almost "mountain torque" element acting on airflow in that area especially when the flow is between south and west (as we have in this setup). Looking at papers such as this http://tellusa.net/index.php/tellusa/article/view/14627 , kind of not surprising that such rotations or shears in the flow would set up in these environs.

Edited by kumquat
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Why do we NEED a stratospheric warming? Other parts of the northern hemisphere do just fine without one. Genuine question.

Read the Strat thread to find out why.We don't always NEED it, but it improves our chances of some snow particularly with a deep cold polar vortex. Edited by mountain shadow
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Why do we NEED a stratospheric warming? Other parts of the northern hemisphere do just fine without one. Genuine question. 

 

We don't, even if we do get one it's rolling a dice as to what positive effects it has on these islands. Would probably help though, need all the help we can get at the moment I think!

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At 174 on the Ens there are seven Perturbations showing Easterly's...

A few -8c 850s coming in, 1 -10... Is this going to be a better set I wonder

Edited by Ali1977
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Just to add to my earlier post heres the ECM prediction for T96hrs:

 

post-1206-0-10388700-1389396479_thumb.gi

 

And this is the now T48hrs prediction:

 

post-1206-0-65930800-1389396507_thumb.gi

 

You can see broadly speaking upstream to the east similar to its prediction but there we have the non clearance of that shortwave energy.

 

As I said a few days ago the easterly had a very good chance if three key things verified, indeed if that ECM had verified I was happy to wager on the arrival of an easterly, again the shortwave rides in and harpoons that in terms of the quick route there.

Edited by nick sussex
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The problem with the pattern is that there is not the amplification and as such shortwaves

appear where there is a weakness. They themselves are not the reason for the failure of

the easterly.

Its just the same as when you watch a run over a number of days and you see troughing

over Iceland say pushing further east on each run and shunting a promising Scandinavian

high away back east. The troughing is not pushing the high back east it is the high slowly

losing strength and retreating back east enabling the low to move further east.

 

looks like a flip by the 18z ens. Tiny, tiny straw to clutch although after the ECM t120-144

charts this evening it may be worth keeping the faith until the morning.

Edited by cooling climate
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The problem with the pattern is that there is not the amplification and as such shortwaves

appear where there is a weakness. They themselves are not the reason for the failure of

the easterly.

Its just the same as when you watch a run over a number of days and you see troughing

over Iceland say pushing further east on each run and shunting a promising Scandinavian

high away back east. The troughing is not pushing the high back east it is the high slowly

losing strength and retreating back east enabling the low to move further east.

 

looks like a flip by the 18z ens. Tiny, tiny straw to clutch although after the ECM t120-144

charts this evening it may be worth keeping the faith until the morning.

Its not just the amplification CC, its other factors aswell but anyway maybe we might get the Azores high ridging north route  type set up in tandem with the block route to an easterly, lets hope if that is the case theres still some deep cold to draw on from the east.

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Well considering how much faffing about the models have done this week,i'm finding it hard to understand why so many people are writing of the chances of a cold spell.

 

Especially when viewing the +120 charts with the bitter air advancing towards us from the North Sea,from  the big 3.

 

This is far from done and dusted yet.Roll on this mornings runs.Posted Image

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Little something from me, regarding the jet stream at only 96rs: (models which can show the jetstream at this timeframe)

Posted ImagePosted ImagePosted ImagePosted ImagePosted ImagePosted Image

Above is the GFS, GEM, NAVGEM, CMA, NCMRWF, CFS (1month), now for the ones which go on to develop an easterly of sorts:

Posted ImagePosted ImagePosted Image

Notice how the jet stream of the models which go on and produce the easterly, is diverted south just before it gets to the UK, whereas the non-easterly models have it diverted over the UK/just east of the UK.

On todays runs we need to see the jet shift west and it diverted to the west of the UK, instead of over if we want to stand a chance of seeing an easterly...

Edited by Panayiotis
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Well I hope we see some dramtic changes in the short term soon, GFS is a really poor run from the end of high res until the end of the run, Azores high ridging over us yellows and red it would right off January.

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ECM144 has potential this morning, similar to UKMO at 144 let's see what happens.....

Well it certainly is more pleasing on the eye than GFS this morning, at 168 there was a little more energy heading south & south east from our limpet low and the heights over eastern scandi look stronger.

192 the energy mentioned above ends up over Spain and the scandi heights have drifted a little eastwards, however it looks much better view than last nights run.

Not going to bother too much with 216 and 240 with those changes earlier on in the run, what I might say though is that if we got similar changes this evening in the same direction we might, just might be back in the game end of next week.

Have a good weekend folks

TSNWK

Edited by TSNWK
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