Model Output Discussion - Tuesday 20:25 -->

[cold snap]

Evening.

UKMO is Brilliant after Dodgy Morning

GFS is Stuning

ECM for people that were worried it looks fine to me as we stand,Evolution is alot LOT slower.than

UKMO and GFS by several Days

[Neilsouth]

There really isn't any point in taking in the detail too much, but FWIW the ECM isn't a good output for the SE in terms of getting into the colder air and snow as the low doesn't away south but gets stuck nearby meaning that this part of the country would stay in the milder sector associated with the low. Elsewhere though it would be a case of digging yourself out of the snow!!

Not just that but the wind direction too , ecm is alot better the further north/east you are... Whereas the ukmo and gfs favour all areas to the north/south/east/southeast

[MR EXTREMES]

cold enough at low levels though, looks like a hills event to me, but still FI

i cant see that being a hill event at all the models are in massive agreement the finer detail still to come a couple more days and if things continue this way then meltdown would indeed happen.

but from that chart snow would fall at lower levels to.

as long as it cools nicely then real cold digs in then we will have snow feast.

[yamkin]

ECM 12Z 240h is great

[cooling climate]

ECM t240 is that the vortex sitting on top of us.

There must be a -18c in there somewhere.

The great thing about that set up is that you would be in

that bitter cold for days with high pressure rock solid to

the north and northwest over Greenland acting as the block.

Edited December 9, 2009 by cooling climate

[Frosty.]

ECM at t216 there must be -16 850's over the country surely.

What an incredible chart, and the snow potential would be huge.

I think S.Murr's fainted.

ECM 12z turned into a beauty after a slow start, potentially it's off the scale compared to recent years..as long as it actually happens turning eyes candy charts into reality is the next big test. If the snow potential is realised then I imagine power cuts will occur so no internet be careful what you wish for.

[Snowaddict]

Again, we see a different evolution on the ECMWF 12Z run but that's extreme cold across the British Isles.

Again, although we don't get real cold uppers beginning to approach until Day 6 onwards, it will already be turning MUCH colder from T+72 and T+96.

If anything like today's ECMWF run was to verify, then there would be extreme cold, with extreme snow & we would be locked into a sustained, prolonged and severe cold spell.

Overall, stunning outputs again this evening but I still think we need to be cautious as there will be more ups and downs yet!

[kold weather]

Tamara, the SE is in thickness that is below 515, there would be a mild sector but its rather like December 62 in that, the warm sector would still be very cold indeed, and still cold enough for snow, that 216hrs chart is a stunner, it is indeed better for the north but even down here I'd be shocked not to get some heavy snow.

[Jan_Bromley]

Funny how the people saying it looks stunning living UP norf , what happened to the strong north east winds?. I've seen low pressure systems in this general area like that in winter and snow showers come down across east anglia and die as they hit the south east. Unless the ECM shows north east winds at all next week i'll not be pleased with this run!

EDIT - Kold i'm still not so sure! , but i'd love to be proved wrong

[Neilsouth]

from retron on two

A superb ECM run, the crowning gem in a vintage day of model watching. oApprove For once all of the major models are on board, we've a genuine Omega block on the cards and the jet will be so far south it'll be off the scale.

ECM picks up on the same theme as MetO and GFS, namely the eastern side of the Omega will see a strong jet and thus lows will form. To anyone worrying about those lows, as I said a few pages back, there's no point in worrying as they're inevitable, to not have them would break the rules of physics in this setup!

The question of whether we'll get a glancing cold blow this weekend (as per GFS) is still up in the air, what follows though seems to be pretty much certain. We'll get an Omega setting up around the Denmark Strait and with each successive low hurtling southwards the core of the cold will get closer to the UK. It's most unlikely to be snow all the way, but the chances increase with each passing low.

Most encouragingly, this isn't a pattern which we'll get out of easily, quickly or cleanly. The usual "sink to the SE" option simply isn't available this time!

[ChartViewer]

Not just that but the wind direction too , ecm is alot better the further north/east you are... Whereas the ukmo and gfs favour all areas to the north/south/east/southeast

Hi,

I understand you are looking at Kent and ECM is slower and possibly borderline for SE but to me its the

general synoptics that are wonderful. Belive me the 0z ecm could well show a bitterly NE Wind

Why worry about snow at this point in time........Beautiful synoptics from all 3 models

Details to become clearer Saturday....But we are in for a serious colder spell to be enjoyed.

Regards

CV

[Guest North Sea Snow Convection]

Not just that but the wind direction too , ecm is alot better the further north/east you are... Whereas the ukmo and gfs favour all areas to the north/south/east/southeast

I wouldn't worry - as I say, it is just one output around a theme that will chop and change quite a few times yet. It is too far away to pin down atm.

The main problem with continual delays to the coldest weather is that it gives more time for other things to get in the way. But lots more twists and turns to come yet I expect

[cold snap]

ECM 12z turned into a beauty after a slow start, potentially it's off the scale compared to recent years..as long as it actually happens turning eyes candy charts into reality is the next big test. If the snow potential is realised then I imagine power cuts will occur so no internet be careful what you wish for.

Nothing to getting worried about with ECM Its a Belter but a slow evolution and i for one would be ready to wait for that ,Better ending imo.

Agreement from the Big three tonight of a Cold snap,ECM not iclined to bring it in as fast as the other two

Unreal runs

Edited December 9, 2009 by cold snap

[Jan_Bromley]

Hi Neilsouth,

surely when potential convections have died on the north sea coast it was due to the Wet bulb not being low enough.

In this current scenario, those WB's will be plenty low enough for snow.

regards

jan

[Nick F]

There really isn't any point in taking in the detail too much, but FWIW the ECM isn't a good output for the SE in terms of getting into the colder air and snow as the low doesn't away south but gets stuck nearby meaning that this part of the country would stay in the milder sector associated with the low. Elsewhere though it would be a case of digging yourself out of the snow!!

I think it's great output for the SE and most other parts of the UK, after t+192, any mild air will be pushed way to the south over Sern Europe as the low and upper cold pool is shown moving down from the NE. There might be a brief area of less cold Pm air moving south down the eastern flank of the ridge ahead of the low moving down from the NE, but once winds turn NE it will likely to turn to snow everywhere. Still, it's all theoretical atm ... and we'll be looking at some other evolution on the next run.

[John Snow]

There will be a state of emergency called in the North East if the ECM is true and comes off with probably 3 to 4 feet of lying snow before even drifts are taken into account

Not so good for us down here but Tyne and Wear and Durham and North Yorkshire will be cut off if this comes off :o

[SMU]

ECM at t216 there must be -16 850's over the country surely.

What an incredible chart, and the snow potential would be huge.

I think S.Murr's fainted.

Im back- off the floor-

My opinion of the ECM is its wrong at 72/96 & 120- but co incidentally picks up the GFS shortwave at 168 & therefor arrives at a similar solution-

What interests me APART from all the stuff going on in the mid term is the backgroun signal for a large low pressure to elongate & head towards Portugal-

IF IF IF this gets anywhere close under the block around the meridian then the UKL will get hit hard from the Easterlies on the northern flank....

S

[DAVID SNOW]

ECM t240 is that the vortex sitting on top of us.

There must be a -18c in there somewhere.

The models look great, but is it just me or do we always seem to be 7 or 8 days away from the proper cold?

Two days ago the models had us in synoptic heaven for a weaks time, concerned we dont seem to be getting closer.

[bluearmy]

The ecm looks great but note that the shortwave doesnt really clear our lattitude. granted that thicknesses are low enough so it'll be fine, but some have worried about this shortwave being carried sw towards the atlantic trough and taking the real cold west with it to our north. i hope this isnt the first sign of ecm trending this way. if it is, tomorrows runs will continue to take this shortwave on a more ne - sw journey. GFS having brought a stronger e flow ahead of the shortwave has cold air over us anyway so doesnt look terrible on the ens that go in this direction. ecm, being slacker would be a 'let down'. its the only real risk i can see from todays output.

[Steve Edgefield]

I am a little sceptial about these lows too. A similar thing happened in February this year where south eastern & eastern coastal counties were tied into the mild sector with just disappointing rain and always marginal. I realise the depth of cold here could well be different but with the North Sea still so warm, it would have to be 'proper' cold to deliver on the coast. Will reserve judgement to the nearer timeframe! Any downgrades to the depth of cold will not be a good thing though - IMBY anyhow.

The main problem with continual delays to the coldest weather is that it gives more time for other things to get in the way. But lots more twists and turns to come yet I expect

Edited December 9, 2009 by Steve Edgefield

[cyclonic happiness]

The models look great, but is it just me or do we always seem to be 7 or 8 days away from the proper cold?

Two days ago the models had us in synoptic heaven for a weaks time, concerned we dont seem to be getting closer.

I can understand you concerns but the fact that all the models are more or less in sync about the cold spell happening, the only thing now is to iron out the details.

All runs are looking very cold and snowey, don't worry too much about FI most of the excitment is in the reliable timeframe or just into FI. :o

[sundog]

Again, we see a different evolution on the ECMWF 12Z run but that's extreme cold across the British Isles.

Again, although we don't get real cold uppers beginning to approach until Day 6 onwards, it will already be turning MUCH colder from T+72 and T+96.

If anything like today's ECMWF run was to verify, then there would be extreme cold, with extreme snow & we would be locked into a sustained, prolonged and severe cold spell.

Overall, stunning outputs again this evening but I still think we need to be cautious as there will be more ups and downs yet!

Hi SA,

How do you think things are shaping up for us in Ireland. Great charts again today,im starting to get really excited i must say. Great potential for a great cold spell the like we have not had for many a year.

[pyrotech]

GFS has been pretty accurate even in fi over last 7-8 weeks, including percipitation.

I am quietly impressed with it. However that was with an active Atlantic which GFS does pretty well with.

This is a totally different scenario, i think GFS has been very persistant with the trend for cold weather, but in previous years it has com up with great charts that just dissappear. This year all the models have joined in on this merry-go-round so GFS is not alone predicting it. Will be interesting to see what we finally get compared to the charts.

If this comes off which looks very good right now, then it really is hats off to the GFS for seeing the changes over the USA and changing the pattern over here in Europe almost 7 days ago.

I do hope the parallel GFS is the new one and is even more correct with what will actually happen as that has been awesome for cold too

Anyone got info on the parrallel GFS?

[Guest North Sea Snow Convection]

The ecm looks great but note that the shortwave doesnt really clear our lattitude. granted that thicknesses are low enough so it'll be fine, but some have worried about this shortwave being carried sw towards the atlantic trough and taking the real cold west with it to our north. i hope this isnt the first sign of ecm trending this way. if it is, tomorrows runs will continue to take this shortwave on a more ne - sw journey. GFS having brought a stronger e flow ahead of the shortwave has cold air over us anyway so doesnt look terrible on the ens that go in this direction. ecm, being slacker would be a 'let down'. its the only real risk i can see from todays output.

I think that is maybe what I am getting at. A trough is effectively set up from NE to SW which cuts off the path of the colder air southwards and westwards and larger areas are kept on the 'wrong' side of the polar front.

But that may well not happen anyway. First things first. I said a few days ago I was pleased that the rain is stopping. That is still the case

Edited December 9, 2009 by North Sea Snow Convection

[John Snow]

I am a little sceptial about these lows too. A similar thing happened in February this year where south eastern & eastern coastal counties were tied into the mild sector with just disappointing rain and always marginal. I realise the depth of cold here could well be different but with the North Sea still so warm, it would have to be 'proper' cold to deliver on the coast. Will reserve judgement to the nearer timeframe! Any downgrades to the depth of cold will not be a good thing though - IMBY anyhow.

I am not an expert by any means but is there any chance that the east will get the equivalent of "lake effect" snow ? except with warm North Sea as opposed to lakes obviously but lake effect in America delivers unprecedented amounts of snow