Model Output Discussion - 30th November onwards

[No Balls Like Snow Balls]

1 very cold day on Friday.

 

 

Then it is bye bye very cold and hello average again.

 

Some you win some you Lose.

 

Does look like further on we are gonna see HP to the South East of the UK for a bit.

 

 

 

Would rather a Greenland high  than a scandi high as theses are notorioulsy difficult to get in the right place to bring us deep cold.

Edited December 2, 2013 by No Balls Like Snow Balls

[stodge]

All I would say is the GFS 06Z Operational output follows a theme which has been there consistently for a number of runs.

 

Whatever its problems with short-term detail, GFS has in the past been excellent on calling long-term trends especially if repeated output after output.

 

One abiding memory is that it called the breakdown of the 2010 cold snap early consistently and persistently and was thoroughly vindicated.

 

Obviously we need to see this develop into the high-res area where it isn't for now and if it's there this time next wek we can start getting more interested but it's a consistent evolution and therefore not to be dismissed out of hand.

[carinthian]

Well a massive difference between the American and the Euro model. I feel the UKMO may be going for a short sharp cold spell and return of warmer airflow in their outlook. Will be speaking to our forecasters later this morning with their view on the Scandinavian High development as they tend to use ECM in there longer term progs.

 C

Here goes then, the feeling is that GFS is to progressive in dropping the high into the continent with its feed of warmer air mass into Western Europe.The reason being it is not handling the flow pattern over the Med. Beyond 240 hours the jet streak into the Med will strengthen and assit to develop the higher pressure pattern further north than the GFS. Hence a link up to Scandinavian cold high. Confidence is low for both models 40% and a middle ground is favoured over here. Possibly the latest out put from GFS is showing a later shift to come along the Euro Model. 

 C

Edited December 2, 2013 by carinthian

[mpkio2]

I think its time I put in my food for thought regarding the prospects for this Winter.

 

OK, about the upcoming Northerly - many are disappointed about what the models are showing and how GFS/ECM keep shutting the LP system sprawling down from S.Greenland either too East or too West on varianting runs. Although to me it does look as though the LP will be too far East to affect anywhere south of Manchester (I live in London), temps will still be below average for a day or two and, to me, that's better than Zonal temps! I do thinks Scotland will get some Heavy wintry showers and some strong bitter winds, with some -10c 850hpa upper air hitting Scotland and North England (-5c 850hpa for the rest of us!).

 

The recent GFS runs have also shown the LP system moving more of West to East movement across the PV to the North of us:

 

A day later, the LP system bringing down the "Arctic air" is sitting to NE of the UK over Scandi:

 

From what the models were showing a few days ago, the LP was projected to make a NW to SE movement down the country heading into Europe, but even that has changed. Point being here is the models are constantly changing due to the models trying to get a hold of the always developing upperstream pattern that is occurring in the atmosphere over the NH (Thanks to via Altuein(sp?) High). I don;t think the models can get to grips with the overall pattern and we will some changes as the weekend draws nearer (Finer details are subject to change!).

 

I think the ECM 0z has lessened the cold northerly, but it has been toying with this idea in it's 12z's over the past few days so I'm not all that surprised to be honest. Still, shows a couple of cold days with a high risk of snow in the North.

 

Now we get to the interesting bit! As most have mentioned, the GFS has been hinting in its FL's that some sort of HP may be setting up either over the UK or Europe which then leads to the Russian HIgh linking with ours over Scandi, creating a High-block. Even in the far reaches of 06z FL we have something like this:

 

Even the 240h on today's ECM 0z shows a Scandi high (Admittedly creates it much more faster and, iMO, seems too progressive):

GFS 06z 240h is nothing like ECM.

 

Do I think it will turn out exactly like that? No, I don't think so. But a trend is occurring in both GFS and ECM for height rises around Scandi in FL. I think its a good trend to take forward and hoping it will show its face more and more and pushed forward into the reliable in due time. Again, the models will flip-flop alll, about and will drop and bring back ideas all the time, so just relax and see how things pan out in this very interesting model watching period! I'm feeling optomisitc about what may be in store for us! Oh and remember:

 

The models don't drive the weather.

Edited December 2, 2013 by mpkio2

[Ian Brown]

Here goes then, the feeling is that GFS is to progressive in dropping the high into the continent with its feed of warmer air mass into Western Europe.The reason being it is not handling the flow pattern over the Med. Beyond 240 hours the jet streak into the Med will strengthen and assit to develop the higher pressure pattern further north than the GFS. Hence a link up to Scandinavian cold high. Confidence is low for both models 40% and a middle ground is favoured over here. Possibly the latest out put from GFS is showing a later shift to come along the Euro Model. 

 C

 

Thanks for that C, the other problem in terms of an easterly for the UK from this route is that it wouldn't be a 'beast' just a chilly flow, as the easterly wouldn't have formed on the Northern side of the jet.

[Matty M]

Well the northerly we have chased for near 10 days is almost not going to materialise and now we begin another chase for a FI easterly.

[Frosty.]

The Gfs 06z op run might be up to it's old tricks..eastward bias, and even if it isn't, it still looks wintry across the uk towards the end of the week with a lot of snow across the far north and some wintry showers further south. I think a westward correction on the 12z is probable but that's just my opinion based on the better looking ecm.

[SW Saltire]

All I would say is the GFS 06Z Operational output follows a theme which has been there consistently for a number of runs.Whatever its problems with short-term detail, GFS has in the past been excellent on calling long-term trends especially if repeated output after outputOne abiding memory is that it called the breakdown of the 2010 cold snap early consistently and persistently and was thoroughly vindicated.Obviously we need to see this develop into the high-res area where it isn't for now and if it's there this time next wek we can start getting more interested but it's a consistent evolution and therefore not to be dismissed out of hand.

The GFS did forecast the breakdown of the 2010 spell from afar, however, that was only a result of its tendency to overemphasise te strength of the Atlantic which actually turned out to be correct. I could rebuttel you with a far more recent example of the converse. Late march 2013, a low was due to track (according to GFS) through the north of Scotland bringing milder uppers. Incredibly slowly did the GFS start to 'slide' the low. It ended up only just fringing into Southern Scotland being huge drifts to myself and many others. The centre of the depression was somewhere near Central England, thus I believe is strong evidence of the GFS having a bias towards introducing zonality wherever it can. The GFS seems to be 'correct' according to some, by default. It did not fully come inboard therefore it was correct is their reasoning. However, I am of the opinion that if a model is incorrect upstream and that the broad scale pattern presented previously was completely incorrect then it has not verified very well either. The ECM has failed us on a micro scale but in a wider context has been far more accurate the GFS Edited December 2, 2013 by SW Saltire

[Frosty.]

Those in scotland, north of the central belt and across aberdeenshire are in the firing line for significant snow by the second half of thursday, through thurs night, all day friday, friday night & saturday morning, 10-25 cm for some areas with drifting in the severe gale force nnw'ly winds.

[MR EXTREMES]

It has to be said Scandinavia in the last four years has been a prime location for heights.

And I think it's very plausible as is the long drawn blow torch sw flow so here we go again round two I'd like to add that if heights do setup into Scandinavia then we could get something very memorable as low pressure systems into the Atlantic could under cut.

So be a good idea to keep an eye On the jet stream and developments over in the state's and noaa take on the models.

And what are noaa thoughts Nick?

[bluearmy]

http://www.weathercast.co.uk/services/ensemble-forecast.html

[carinthian]

Thanks for that C, the other problem in terms of an easterly for the UK from this route is that it wouldn't be a 'beast' just a chilly flow, as the easterly wouldn't have formed on the Northern side of the jet.

hi Ian,

 I think the UKMO will be less progressive than GFS to a milder option, but is more likely to favour this outcome rather than the ECM current thinking to a quicker route to cold A/C feed. Maybe their lunchtime medium range up date will throw some light on this .

Cheers

 C

[Frosty.]

Some of the GEFS 06z perturbations show a longer arctic snap, especially for the north but also increases the risk of snow further south too. Even at this relatively short range, there is a lot of uncertainty on how close to the west the atlantic high will be and also the alignment and intensity of the scandi trough, until those are finely tuned, we just don't know how wintry or not it will be across the southern half of the uk, we really want to see the mean adjust westwards but as things currently stand. The far north / ne would have to see significant downgrades to miss the snow showers and disruption as they are in the best position to tap into the coldest T850 hPa on thurs & fri and possibly the first ½ of saturday.

[forecaster]

Chasing easterlies is a very long game from a starting point of HP over France.

 

Maybe a time to sit back and absorb this thread: http://forum.netweather.tv/topic/75166-model-output-discussion-12z-04122012/page-47 (not picking any page in particular, just the latter stages).

(Glad I was not in the UK for that event!)

 

Here is the EC det +192hr prog for that easterly:

 

 

And this is what actually happened:

 

 

A few days of chilly weather follow by a breakdown to westerlies.

Is this going to happen all over again?

 

Just noticed the 15th is a better example:

 

 

Edited December 2, 2013 by forecaster

[SW Saltire]

Maybe a time to sit back and absorb this thread: http://forum.netweather.tv/topic/75166-model-output-discussion-12z-04122012/page-47 (not picking any page in particular, just the latter stages).

(Glad I was not in the UK for that event!)

 

Here is the EC det +192hr prog for that easterly:

 

 

And this is what actually happened:

 

 

A few days of chilly weather follow by a breakdown to westerlies.

Is this going to happen all over again?

 

Just noticed the 15th is a better example:

 

 

 

 

It's still too raw!

This is a timely reminder of how fickle easterlies are. The FI period could become very low i.e. t48 with some easterlies. Let's hope the less experienced viewers heed your advice and DO NOT bank on an easterly coming to fruition until cross model agreement at a timescale that is within 2 or at most 3 days

[The Northern Ramper]

Yes I certainly think that is likely to be the case, will be interesting to see the METO update later today and see if they mention very mild conditions towards the end of the 6-15 dayer. Chasing easterlies is a very long game from a starting point of HP over France.

But not as long as it backing west from Siberia.

[Gavin Hannah]

Maybe a time to sit back and absorb this thread: http://forum.netweather.tv/topic/75166-model-output-discussion-12z-04122012/page-47 (not picking any page in particular, just the latter stages).

(Glad I was not in the UK for that event!)

 

Here is the EC det +192hr prog for that easterly:

 

 

And this is what actually happened:

 

 

A few days of chilly weather follow by a breakdown to westerlies.

Is this going to happen all over again?

 

Just noticed the 15th is a better example:

 

 

 

 

 

Why!?!?!!?!?!?!?!?!!     lol.

[Snowman.]

Maybe a time to sit back and absorb this thread: http://forum.netweather.tv/topic/75166-model-output-discussion-12z-04122012/page-47 (not picking any page in particular, just the latter stages).

(Glad I was not in the UK for that event!)

 

Here is the EC det +192hr prog for that easterly:

 

 

And this is what actually happened:

 

 

A few days of chilly weather follow by a breakdown to westerlies.

Is this going to happen all over again?

 

Just noticed the 15th is a better example:

 

 

Shortwaves...

 

Those god damn shortwaves.

[nick sussex]

It's still too raw!

This is a timely reminder of how fickle easterlies are. The FI period could become very low i.e. t48 with some easterlies. Let's hope the less experienced viewers heed your advice and DO NOT bank on an easterly coming to fruition until cross model agreement at a timescale that is within 2 or at most 3 days

I remember it well! This thread was like a scene out of Casualty! I remember writing a post detailing how a combination of factors led to the subsequent implosion of that easterly. If my memory serves me correct the first thing that went wrong was the remodelling of a low moving east across the USA, this was expected to be amplified and as it headed east sharpened the low to the west of the UK to help eject energy se, instead it was flatter and changed track, at the same time shortwave activity north of Norway stopped positive heights from extending west over the top of a low that headed south into the continent. What was really tragic that the UK could have still managed a cold spell of varying forms if just one of those things had gone wrong, as it was both together ended hopes.

[shedhead]

The Gfs, on balance has more chance of being wrong about the outlook than the Ecm...it's not over yet shed...well it's not begun either but that's beside the point, the Ecm 00z ens mean is still showing a strong arctic blast on friday and saturday am further east..the fat lady is not singing yet, hopefully she will be kept backstage and then sent home in a cab

More likely to be on a train Frosty, the Marrakesh to Moscow Express...departing on Sunday....

[TSNWK]

Afternoon. Todays metoffice updates suggest to me low presure to the northwest with a euro high lingering over the South east and near continent. Not one word sugesting any consideration of todays 00:00 ECM.

[Yarmy]

I'd forgotten it was as far out as T192. It was all over on the models 48hrs later (before really):

 

 

…which ended up pretty close to the truth...

 

 

 

Fragile things indeed. I recall the press had picked up on it the next day and people on a football forum I use were starting to talk about it excitedly at the same time as I was watching it all unravel. 

Edited December 2, 2013 by Yarmy

[Frosty.]

The latest fax charts are still indicating a very wintry and windy spell later this week across the far north of the uk, eventually that arctic blast sweeps south to the rest of the uk, especially down the eastern side with snow showers but the heaviest snow and strongest winds looks like being to the north of the central belt, possibly to the north of the great glen and across aberdeenshire, probably the most severe conditions across the n.isles on thurs / fri with blizzard like conditions, some kinks in the tight isobars could indicate enhanced snow showers activity across the far northeast of scotland and isles in the nnw'ly gales but frosts look like becoming widespread by friday and penetrating as the strong winds will exacerbate the cold with a scattering of snow flurries, even for the south but mostly for counties bordering the north sea with the north yorkshire moors and lincolnshire wolds probably getting a light covering. Then turning fine as pressure rises from the west during the weekend with sharp frosts, especially across the snow fields in the north, early next week it's set to become milder across the n and w with sw'ly winds and occasional rain, the south and east probably remaining fine and with low level cold air in situ and widespread frosts, probably with an increasing risk of fog as winds fall light with the anticyclone becoming centred to the southeast of the uk across the near continent. Lower heights to the northwest of the BI.

[Snowman.]

Latest CFS 1 is very blocked.

 

Actually this week is the closes it gets to the Atlantic making in roads.

 

Scandi block becomes more and more dominant and towards then end of the run is sets up the omega block setting.

 

Very interesting times ahead of us for sure patience is always required with an easterly as its the hardest to get here but when it gets here it delivers some of the prospects.

 

Even a channel low is thrown in there.

 

 

One problem is that the CFS is that it's completely different to all other models at 192+ it doesn't develop the SSW flow with heights NE keeps us in a sturn WNW flow.

 

 

However its likely to stay blocked well into December with the likely hood of a cold spell at the start of January to mid Jan, this has been a recurring theme with the Christmas period likely to be the trigger event with the most unsettled weather as blocking extends west and sets up some sort of cold block.

 

Greenland heights are still a possibility but not within the next 15 days, its likely to be a slow process but I reckon we can pull through with something decent, the strat has already had interesting start this year so don't rule out any possibilities on the continuing theme of stress applied to the vortex.

Edited December 2, 2013 by SN0WM4N

[Purga]

Afternoon. Todays metoffice updates suggest to me low presure to the northwest with a euro high lingering over the South east and near continent. Not one word sugesting any consideration of todays 00:00 ECM.

So a pint of mild for Xmas then

Edited December 2, 2013 by Purga