Model Output Discussion - 30th November onwards

[weatherguy]

Another downgrade from the ECM in the short term overnight, with everything pushed further east (still good though, just can't afford things being much further east).  On the plus side, an upgrade in the Scandy potential for a more substantial cold spell  

[snowangel32]

This is torture so the northerly artic blast has gone unless you live in the north, so from say Manchester south cold and dry unless we get upgrades and can push that ridge west a bit. And now we are chasing a potential easterly 10 days away when the models can't even agree on Thursday. Its only December 2nd its going to be a long winter

Edited December 2, 2013 by snowangel32

[SW Saltire]

Beggining to lose a bit of faith in the ECM now. That's twice in a short period that's it's been off the mark, now it's going for a Scandi High, and we are not far off a year since it failed big time on an easterly. I will be waiting for UKMO to join that party before I even begin to get interested.

Agreed, the 'daddy' ECM has shown a possible bias in showing overamplification perhaps at times. This is rather frustrating. It does lend itself to better model watching with the GFS rolling about for run after run after run... And the ECM producing great charts for coldies. Thus, it would seem imperative that the UKMO must be inside in order to be confident in any cold spell or pattern change in general. The GEM I don't believe has been performing as well as when it was touted as one of the 'big three' it seems to be just as poor as the GFS at times. Also, well done BA on 5,000 posts! Edited December 2, 2013 by SW Saltire

[IDO]

Shall we wait to see what uppers we receive at the end of the week, look at the actual charts and then, assuming we aren't too busy chasing an easterly, trawl back through th modelling to see which model made the best fist of it. (And you can't go past T144 or ukmo has to be excluded)Will make a more detailed post looking forward after the naefs/ECM eps are out. safe to say a building scandi block is much more difficult to pin down than a trough/ridge/trough moving w to e from two weeks out.

 

 

Yes wait till its happened. But even from my untrained eye the current output makes the ECM data look poor.

 

Thats twice in a few weeks ECM have overdone the cold. We have to take this into account when looking at anything past T120 with them now, otherwise many casual viewers to this forum will get led up the garden path again.

 

A model split as to the possible next cold spell with GFS saying no to a Scandi and ECM yes. We will see...

Edited December 2, 2013 by i'm dreaming of...

[SLEETY]

loving the ecm today,a quick arctic outbreak at the end of the week,followed by a mega bitter easterly a few days later.

[shedhead]

Don't understand the downbeat mood, we are on the cusp of our first arctic blast of the winter and further into the month we could be looking at a cold blocked pattern, chin up peeps :-)

The downbeat mood is very simple to understand in light of recent model outputs.  When the expectation bar is raised so high, it should be no surprise to see things swing the other way when those high expectations look more and more unlikely to be realised. That's it in a nutshell as far as I'm concerned. 

 

It's been said several times already this Autumn/Winter, but it's still worthy of further reiteration....any N'erly or E'erly progged beyond T+120hrs should be treated with extreme caution, at least as far as detail is concerned.

Edited December 2, 2013 by shedhead

[pdiddy]

loving the ecm today,a quick arctic outbreak at the end of the week,followed by a mega bitter easterly a few days later.

I can see the cold blast Sleety, but not the bitter Easterly.  Do you have a chart for that one?  ECM shows Sussex in uppers of 4c, or am I missing your location?

[swilliam]

Correct me if I'm wrong but not a single GEFS ensemble supports ECM at day 10. Until there is more support I would say its a 5% chance that we get an easterly in 12-15 days time

Try looking at 2, 3, 4 11, 12, and 17 which are all quite similar. and others develop the link at a later date.

[SW Saltire]

Yes wait till its happened. But even from my untrained eye the current output makes the ECM data look poor. Thats twice in a few weeks ECM have overdone the cold. We have to take this into account when looking at anything past T120 with them now, otherwise many casual viewers to this forum will get led up the garden path again. A model split as to the possible next cold spell with GFS saying no to a Scandi and ECM yes. We will see...

What is the middle ground scenario between no Scandi high and a high, a ridge? Would we have a drift of the continent? The GFS will not accept the high, it can spot trends at t-300+ but for some reason in nearer FI it will flatten all who halt the Atlantic train. As you say, the ECM may well show a strong high but that must be treated with more scepticism than previously thought. Most likely a middle ground scenario will win out

[Shunter]

FWIW ....in NOAA's preliminary discussion this morning for Thursday -Sunday ( 05-08th Dec ), they are still favouring the Euro solution ( 01 12z EC Ens mean ) over their own models. So ECM may still be the most likely solution for this  !

http://www.hpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdepd

Edited December 2, 2013 by Shunter

[IDO]

Without looking at clusters and splits, on their face value GFS and ECM T240 means are quite similar with MLB to our east and a W-SW-S flow:

 

 

Edited December 2, 2013 by i'm dreaming of...

[Frosty.]

GEM 00z shows a strong Arctic blast for friday, subsiding into saturday but turning very cold and icy with sharp frosts and snow showers to the n & e.....a cold and frosty weekend, it's a short sharp cold snap.

[tight isobar]

What is the middle ground scenario between no Scandi high and a high, a ridge? Would we have a drift of the continent? The GFS will not accept the high, it can spot trends at t-300+ but for some reason in nearer FI it will flatten all who halt the Atlantic train. As you say, the ECM may well show a strong high but that must be treated with more scepticism than previously thought. Most likely a middle ground scenario will win out

..with such split agree GFS/ECM (+ various).one could suspect halfway house scenarios,may not at this time likely outcome.imo it will clearly go one way or other ie ecm/ gfs route. The split agree is v, pronounced,and to my eye as again It's a 50/50 road. I'm sure there will be firming shortly for mid term likelihood.And also alignment of more cross model agree rather than the messy split in front of us presently ....

[johnholmes]

All of the 3 anomaly charts I use have reasonably consistently over the past 4 days shown signs of height rises being moved e/ne of the UK and this continues this morning on both ECMWF-GFS outputs with the 500mb flow becoming south of west into the UK from the now main trough way west of this country; about 30 west.

link below

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

[SW Saltire]

..with such split agree GFS/ECM (+ various).one could suspect halfway house scenarios,may not at this time likely outcome.imo it will clearly go one way or other ie ecm/ gfs route. The split agree is v, pronounced,and to my eye as again It's a 50/50 road. I'm sure there will be firming shortly for mid term likelihood.And also alignment of more cross model agree rather than the messy split in front of us presently ....

I suppose from a broad scale then you are correct the high will happen or it won't but from a UK pov the high could occur but the cold may not be advected far enough westwards to get deep cold, as ever this is just speculation on a trail that is only just beginning...

[Summer Sun]

ECM ensemble shows Friday will have strong northerly winds making it feel bitterly cold

 

 

Saturday remains cold with the winds starting to ease as pressure rises from the west

 

 

From Sunday pressure builds and it stays

 

 

The 850's rise but whether surface temperatures respond remains to be seen

Edited December 2, 2013 by Summer Sun

[Gibby]

Good morning. Here is the latest Model Analysis report taken from www.norton-radstockweather.co.uk for today Monday December 2nd 3013.

 

All models show High pressure positioned over England with flat calm conditions for many under largely cloudy skies. This weather type with only minor local variations continues through until Wednesday. The North will see a band of patchy rain move South through tomorrow and Wednesday as a cold front slips South. This then reaches the South late in the day before another front crosses South over the UK on Thursday bringing a notable drop in temperature, occasional wintry showers of sleet or snow for a time in the far North and East while Southern and Western areas become clear and cold with frost at night but sunshine by day to start off next weekend.

 

GFS then takes High pressure away SE next week with cloudy and milder air being pumped up across all areas from the South and later the SW. Temperatures would exceed normal for all with time but it might take rather longer for this to happen in the SE early next week. Rain at times would develop for a while as fronts moved NE in the flow. Later in the run High pressure then migrates back NW over Europe to the UK bringing yet another spell of quiet and benign, rather cloudy conditions and with warm uppers we rely on an inversion to set up not to transfer very mild conditions down to the surface should it evolve as shown.

 

UKMO shows next Sunday as a milder and breezy day across the North as winds back WSW with a front carrying cloud and a little rain East through the day. In the South quieter conditions remain and with High pressure close to or over the area then dry and potentially bright weather continues with some overnight frost and fog possibilities look more likely.

 

GEM today shows High pressure receding South early next week into Southern Europe allowing milder SW winds to become established over all areas. With a bank of deep Low pressure stretching West to East to the NW of the UK rain at times would be inevitable, heaviest in the NW with strong winds reaching gale foce too at times. Temperatures would be close to average at worst and the SE may become rather mild at times.

NAVGEM too shows High pressure receding SE early next week with milder SW then Southerly air affecting the UK, probably rather cloudy and benign again with any frost and fog risk at first in the SE gradually becoming less evident with time.

 

ECM today holds a spark of interest as it bucks the trend from the other operationals in as much as it rises pressure over NE Europe next week which absorbs the High near to SE Britain into a ridge which would result in a much increased risk of the weather staying cold, certainly over the South with lower temperatures extending North through the week. With a continental feed of air across the South sunny skies by day seem more possible but with the usual caveats of widespread night frosts and freezing fog patches which could become very stubborn and slow to clear over England and Wales with time. It should remain dry though.

 

The GFS Ensembles are dreadful if it's cold your looking for with an almost blanket approach to milder conditions for all next week with High pressure to the SE. There are varying degrees to what influence that High pressure may have on conditions across the South and SE as some members show rain at times for all but if the High stays closer to the SE then things could stay rather dry with just occasional rain here with the majority of rainfall and strong winds likely in the North and West.

 

The Jet Stream shows the flow moving SE down the North Sea later this week moving East before the trend this morning is for a new arm to move NE across the Atlantic and over the UK in the second half of the run then moving on NE towards Scandinavia over the top of High pressure over Europe.

 

In Summary today it looks more likely than not that the end of the week's cold snap will be a blink and miss it affair with little significance away from the far North and NE where some snowfall in the form of showers may occur for a time. High pressure then builds back for a time next weekend before most output wants to shift it SE into mainland Europe bringing mild and changeable conditions across the UK with strong winds and rain at times, heaviest and most frequent towards the North and West. Then we have the 'ECM' model which throws a spanner in the works by building High pressure strongly over NE Europe next week which if evolved would totally change the complexion of conditions over the UK next week with frost and freezing fog patches along with brighter dry days much more likely next week with below average temperatures. However, it looks a little isolated and needs support from it's ensemble members and future runs to ascertain this as a trend to watch through the coming days.

[TwisterGirl81]

Well this GFS this morning shows high pressure pretty much over us right until the end of the run  I know we get the cold shot the later part of this week but that's all if you take the GFS at face value.

 

I just hope it's not a cloudy high although given the time of year and the sun isn't as strong....

 

Well thankfully at least southern area's had a pretty decent summer with high pressure over us good amounts of time and the pressure is back it seems for a little bit...

[BLAST FROM THE PAST]

Well, we had UKMO join ECM for one run, GFS moved away from spoiler shortwave/LP coming off Newfoundland yesterday 00z but has moved it back in.  Currently in my book, ECM over did it and is backing away a touch.  Its settling into a 2 day cold shot with it subsiding back end of day two as the main thrust has been shunted eastward.

 

BFTP.

[SLEETY]

I can see the cold blast Sleety, but not the bitter Easterly.  Do you have a chart for that one?  ECM shows Sussex in uppers of 4c, or am I missing

 

your location?

 

BITTER AIR OVER EUROPE MOVING WEST

 

NEXT FRAME

 

 

 

 

Edited December 2, 2013 by SLEETY

[Frosty.]

Ecm 00z ensemble mean shows a potent Arctic blast later this week, especially for friday although what you don't see on this is the cold air will be flooding south across the uk on thursday with heavy snow showers further north driven south on nw'ly gales,,but friday looks wintry for all with sunshine and hail, sleet and snow showers, especially for the n & e, the isobars look very tight in the far north where there could be severe nnw'ly gales with frequent heavy snow showers with drifting, the very wintry weather then persists through saturday across the far northeast in particular but it's an improving picture from the west as high pressure builds in but very cold and frosty through the weekend, then as the high drifts southeast early next week, a sw'ly airflow begins to push around the northwest corner of the uk so turning a little milder as time goes on with some rain and drizzle and a rapid thaw of the snow in scotland but the milder intrusion might be brief as the high begins to build later next week with frosty nights and fog patches becoming more widespread, this fine and chilly weather extending to the north / nw later.

Edited December 2, 2013 by Frosty.

[Roger J Smith]

I would also expect reality to be closer to GFS/GEM blend than ECM by day ten, in fact this may be one of those cases where reality follows a majority and overturns the outlier. Last week it was the GFS screwing up the track of the east coast low in the USA, that time the other three majors were in agreement on an inland track while the GFS wanted to go about 20 deg east of them until quite late in the outlook period (I think it finally caught on around 120h or so). 

 

Previous poster's comments about my forecast is probably based more on LRF than CET contest where I noted that I was applying game theory and in the LRF there was no 3.5 C error, more like one deg perhaps for November. Anyway, if one failed forecast was a criterion for ignoring guidance, there would be no model thread at all. We'll have to see what the model error for Bavaria is on 12 December, somebody's going to be 20 degrees out there.

Edited December 2, 2013 by Roger J Smith

[Severe Siberian icy blast]

The unfortunate realisation this morning that this severe cold spell with uppers below -10 has once again been watered down considerately , deep cold for one day , we should learn massive lessons from this , and those chasing deep cold at 240z on the ECM should think realistically if it's actually gonna happen ?

The models still haven't got it right for 4 days time , so the chance of them getting it right for 10 days time is very very slim .

Everyone backing the ECM but in reality it's backed right off the cold weather , it's gone from 4 days cold spell , to one day , the snow will be in Scotland , and maybe through western areas , with a few through the Cheshire gap , but nothing to get excited about .

The gfs has been to progressive as always , but the ECM has been far to amplified .

I think the scandi ridge will set up shop , but if I had to make a shout I would say we will be too far west , and more likely to have extremely mild southerly winds rather than cold easterlies .

I hope I'm wrong I really do , I love snow as much as anyone but I'm not gonna be unrealistic again , and previous years Iv had my snow blinkers on all winter only to be let down time and again so to save disappointment it's best to look realistically at the models .

[IDO]

I have not got access to the ECM postage stamps and probably not allowed to post tweets so i am rehashing what Matt Hugo said re the ECM Members.

 

----

 

"At T240 only 7 out of 51 support a Scandi High/Easterly". (This ties in with the ECM mean at the same time.)

 

"However by D11-D15 27 members now support the Scandi/easterly".

----

 

So ECM seeing a settled period with a SW flow but their long term trends towards heights in the NE/N. See if any of the other models go that way.

Edited December 2, 2013 by i'm dreaming of...

[Yarmy]

I would also expect reality to be closer to GFS/GEM blend than ECM by day ten, in fact this may be one of those cases where reality follows a majority and overturns the outlier. Last week it was the GFS screwing up the track of the east coast low in the USA, that time the other three majors were in agreement on an inland track while the GFS wanted to go about 20 deg east of them until quite late in the outlook period (I think it finally caught on around 120h or so). 

 

Previous poster's comments about my forecast is probably based more on LRF than CET contest where I noted that I was applying game theory and in the LRF there was no 3.5 C error, more like one deg perhaps for November. Anyway, if one failed forecast was a criterion for ignoring guidance, there would be no model thread at all. We'll have to see what the model error for Bavaria is on 12 December, somebody's going to be 20 degrees out there.

 

OT, but how does Game Theory apply to estimating the CET, Roger? I must confess (having studied it a long time ago), I can't see how it could be applied to the weather. Have you got a link?