Model Output Discussion 1st January 2014-06z onwards.

[tight isobar]

All this kerfuffle over weather patterns that don't even exist yet.....My advice for some members is to take a breather from this thread for a little while, get some fresh air, and only then come back in and look at the model output objectively. constant analyzing run for run, chart for chart is fraught with danger. As Kriss, Nick Sussex, Steve Murr (just to name a few) advise, look at the bigger picture, look at the hemispherical patterns evolving, look for trends post T96, as at this stage FI lies at this range IMO. Don't get hooked up over the bog standard atlantic T850 charts (as I know many secretly do  )

 

The current trend as I infer it is for colder conditions to affect the British Isles with an increasing chance of an continental influence with HP situated over Scandinavia....Get that influence in place then see what happens

yes, its hard to stress how the models struggle with such evolution as we face let alone once fruition is reached and what indeed may follow, eyes down for the 12z.

[UV-RAY]

The 144hr I posted shows decent ridging into Eastern Greeny at 144hrs, so IF that happens as shown I think there is more than a fair chance of some proper cold synoptics farther down the line.  You know how difficult it is to get an Easterly set up and that difficulty is shared by the models in trying to nail the evolution of one, so expect there to be much more chopping and changing of the detail...as the last 24hrs has seen. However the big picture remains pretty much the same, so until that changes (as well it might) I wouldn't write anything off.

I still feel we need to see this push further westwards in Greenland, this it may do over the coming 10+ days  but also we may just as easy end up on the wrong side of the block with fronts stalling over the North sea leaving us in a cold/wet regime.

[terrier]

Think a lot rides on the 12z tonight hopefully we will see a westward correction but if not I fear we may have to wait for a second bite of the cherry later in the month.

[bluearmy]

westward/eastward/northward/southward ....... snowking's post from early this morning put it into perspective. sometimes, we have a complex scenario approaching and this is one of those occasions. nothing you can do about it. the stakes are high so we are more bothered about this one. when i saw the T96 ecm this morning, my mind immediately flipped back to dec 2012 and the failed easterly. not the same evolution at all but the meeting of the atlantic trough and scandi trough at a latitude north of the uk is 'goodnight vienna' on the initial system and then we have to wait and see if we get another chance if the second trends south. the first fail is likely to dictate a tougher time for the second to undercut successfullly. i'd like to sit here and make an informed post on what to expect and look for but on this one, there really is little point. it doesnt seem that we can get a solution like the clean GEM, given where the other models are so we just have to sit back and 'enjoy' the ride.

[shetland islands]

I believe the current eastward correction of the cold block with continue on the 12z runs, with exception of the GEM, which may just continue its very cold theme. In most cases, getting cold to the UK is difficult, particularly further South. Currently, there is likely to be colder weather to the NE of the UK and slightly cooler weather to the south, but nothing exceptional.

[MPG]

Think a lot rides on the 12z tonight hopefully we will see a westward correction but if not I fear we may have to wait for a second bite of the cherry later in the month.

Theres nothing riding on the 12z output. It has been made clear that next week is normal winter fare for Januray. Possible snow in the north and cold and wet in the south.

[SNOWPLOUGH]

Theres nothing riding on the 12z output. It has been made clear that next week is normal winter fare for Januray. Possible snow in the north and cold and wet in the south.

Unless you have a crystal ball then you cant really say that for certain either. But I agree re the 12z's, this will be far from sorted on todays runs. Plenty more changes to come I feel.Dan

[tight isobar]

I believe the current eastward correction of the cold block with continue on the 12z runs, with exception of the GEM, which may just continue its very cold theme. In most cases, getting cold to the UK is difficult, particularly further South. Currently, there is likely to be colder weather to the NE of the UK and slightly cooler weather to the south, but nothing exceptional.

thats a big call slight tweaks to the west, with energy modeled aligned and correction of a more southerly trajectory...then absorption from the east becomes much easier ie 850hpa floods West we'll see.

[Frosty.]

Lol, . Roll on spring![i

]

Nah..winter is coming, and we will hopefully have another freezing cold march and april :-)

[Dancerwithwings]

Ok the charts are not as good as yesterday, But what the hell! The so called cold don't even hit us untill next week and folk are looking for it to fail and yes that maybe the case,

But until that starts to really show itself, Please stop being so down hearted. I know people mention to the fact and it is a fact that we must be cautious on forecasts regarding Easterlies,

and yes there right most do fail, But most fail in F1 and never reach 144h.We all know they have failed at 72h but thats the exception,

But when people say they won't get excited until it gets near the time frame, Like 48hrs is just going a little over the top.

 

But finally, Theres always going to be a 'wobble' in proceeding, And that's always been the case.. If we have upgrade after upgrade, We would have Icebergs around the uk after 10 days,

And that's never going to be the case...... Nice thought though

If it don't happen, it don't happen.... But until then, Let's be upbeat about the up and coming cold spell

Edited January 9, 2014 by Dancerwithwings

[winterof79]

The METO 144 Does not look too bad to me

 

http://www.meteociel.fr/ukmo/runs/2014010900/UW120-7.GIF?09-09

http://www.meteociel.fr/ukmo/runs/2014010900/UW144-7.GIF?09-09

http://www.meteociel.fr/ukmo/runs/2014010900/UW144-21.GIF?09-09

Shows cold encroaching between 120 and 144 meeting the atlantic air.

 

Just to add it is identical to 06z GFS too

Atlantic air mass  meets siberian air near to us

 

http://modeles.meteociel.fr/modeles/gfs/runs/2014010906/gfs-1-144.png?6

http://modeles.meteociel.fr/modeles/gfs/runs/2014010906/gfs-0-144.png?6

OK not eveyones cup of tea especially the further west and south you are

Edited January 9, 2014 by winterof79

[Jack Wales]

The brief cold spell currently being modelled remains a week away which is still in FI in my opinion. The key elements for the evolution such the cold synoptics are the positioning of the scandi high and the strength of the jet. One factor which models seem to be picking up on is that the progged weakening of the jet into next week may have been a little overplayed. The outcome of a stronger jet would result in the scandi high being displaced to the east and the jet subsequently splitting further east (and the cold diverted into central europe).

At this stage, the ensembles are probably the best gauge for the probability of an easterly occurring next week. However at the moment support in the ensembles is gradually diminishing as we get closer to the reliable timeframe.

At this time of year (and especially so given recent synoptics), I won't dust off my sledge unless we are still seeing these charts after the weekend!!

[ghrud]

Just to cheer all you coldies up, have a look at the latest Met O 6-15 day outlook!

UK Outlook for Tuesday 14 Jan 2014 to Thursday 23 Jan 2014:

On Tuesday there will be some rain over northeast Scotland and showers in the west and southwest. However eastern parts are likely to be fine and dry, with frost and a risk of fog patches at first. Strong winds and further rain, heavy at times, are likely to spread from the southwest during Wednesday. Through the week it may become cold in the northeast, with strong easterly winds and wintry showers. Western and southwestern parts are probably going to be less cold and cloudier with further rain. Later in the month it is likely to become less cold and more changeable, with sunny spells and showers or longer periods of rain, these perhaps more likely in the northwest.

Updated: 1149 on Thu 9 Jan 2014

 

Sorry, but not cheered by this too much. I live in Hampshire. But who knows?

 

[johnholmes]

thats a big call slight tweaks to the west, with energy modeled aligned and correction of a more southerly trajectory...then absorption from the east becomes much easier ie 850hpa floods West we'll see.

 

yes IF

What do you see as the reasons for any slight tweaks as you call them? How likely are they meteorologically?

[Timmytour]

You can talk about your troughs, your energy going above or below or through, what's happening upstream or SSWs.......to me nothing has more impact upon the models going on to downgrade previous eye-candy charts  than a Daily Express headline. it's happened enough times now to be science rather than coincidence!!

Edited January 9, 2014 by Timmytour

[johnholmes]

 

And to answer your earlier Q John, trend being 10-15 days, short lived cold

MO says "All output then does agree later in the period for a return to more mobility in the trend period, biased this time to the NW." 

 

 

thanks for this Jo

[IDO]

Its not hard to see why UKMO are forecasting a return to a westerly flow from somewhere in the 10-15 day range. Both the AO and NAO indices point to a small window of opportunity for the pattern change; both going positive in FI:

 

 AO:     NAO:  

 

The GEFS mean is another way of looking at it:  

 

This sort of makes sense; we have a lull in the Atlantic flow (via the Strat), but the PV remains relatively strong, pent up during the lull, and unless the blocking is favourable, and changes the NH profile, then that latent energy will go its usually route, through the UK. So I would agree  with the Met that a return to unsettled remains the longer term most probable option (safer bet). But again I don't think that the return to a more restrained zonal flow is anything but also transitional.

 

Anyway I thought the ECM mean was very good after T168, and that is where I look for a trend timewise. Right out into FI as well, eg at T348:   ...colder than last night's 12z! No downgrade there, but of course only one run.

 

If that is maintained, I would be very surprised if we didn't see a better op this evening.

 

 

[Mucka]

Plenty of posts talking over-reaction to single runs and natural variation but I think they are overlooking that when all the models (bar GEM) go the same way (in this case the wrong way) then it is unlikely to be run to run variation.

 

Not sure why the MetO 15 day forecast would be considered good, it completely discounts the possibility of GEM being correct.

"It may become cold in the NE, W/SW further rain."

That means they are likely going for something close to this mornings ECM. That would be a big disappointment for many with only the minority seeing snowfall and frankly flooded areas in the W and SW would have little respite.

Also they have totally dropped the cold signal for later in the month but that would be fine if we could get a cold spell nailed for mid month though the models definitely moved away from that this morning.

 

Thankfully we are still talking fine margins so let's hope we see more energy heading SE in this evenings runs but my feeling is that GEM will move toward the other models rather than the other way around. That is just a feeling though and things may look very different again after the evening runs so yes we shouldn't jump overboard but we shouldn't bury our heads in the sand either. This mornings output was what it was, a little disappointing.

Edited January 9, 2014 by Mucka

[TSNWK]

It might be drifting away way folks - 15 years of experience watching these events come and go and the rule of thumb is.

 

1) Cold spell shows up on a couple of runs - Last Weekend Runs.

2) Cold spell shows up on remaining runs -  This Monday Runs.

3) It slowly improves or stays stable - This Tuesday Runs.

4) We get a boom set of charts - This Wednesday mornings runs

5) Next set of charts maintain the theme - This Wednesday evening runs

6) Runs back off - still look ok, but not as good.. This mornings runs.

7) Run continue to back off. Tonights runs.

 

I believe we are at step 6, lets see how step 7 pans out, if it happens then its off....in my humble view.

 

We never got to steps 6 or 7 when cold spells have delivered AKA 2009 / 2010 / 2013

 

Fingers crossed for the 12Z's - The crowds will soon be rocking up

Edited January 9, 2014 by TSNWK

[Man With Beard]

Fascinating tussle between the ensembles this morning. ECM mean at T144:

Very good definition in the highs and lows suggests the ensembles are in fairly good agreement; 995mb low to west of Ireland and 1025mb high over Scandi. The meeting of the troughs (i.e. the dark blues) east and west is slap bang through the UK. That roughly indicates the border between Arctic conditions and less cold conditions - so basically it would be somewhere across the UK, absolutely no sense in trying to say where at the moment, but the chart says "Snow - somewhere in the UK". Mean charts at T168 and T192 suggest a slow sink south so areas without snow initially may get it later on if the Atlantic fronts don't fizzle out too soon.

 

GFS mean at T144

Quite different in that the lows between W Ireland and N Italy do not link up as well, and no link up of the troughs west to east. Probably not as much clustering as on the ECM as the colours in the Scandi High don't go green and the isobars are a bit more flabby. In fact, a look at the individual ensemble members is a bit like mayhem, no agreement between them at all!! http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=1&ech=144

 

You would be tempted, after looking at the GFS, to think that there is no possible way to make a forecast as far out as T144. And certainly, whilst the GFS ensemble members continue to look chaotic, there is going to be doubt in the forecast, perhaps even a small doubt that cold air is going to reach any part of the UK. But you can see that the ECM ensembles are far more in agreement with each other than the GFS's, since by T192 the difference in definition of highs and lows between the two ensemble means is even more marked:

That suggests the ECM has far more confidence in its own evolution than the GFS has. The ECM is fairly confidently of some sort of block to our north still in place by T192 and even more confident that a decent low pressure system will be centred over Biscay (note - this is a fairly good set-up for cold and snow over the UK, as long as there isn't too much of a southerly flow). However, the GFS suggests there might be some blocking to our north-east and some sort of low pressure over France but goodness knows exactly where.

 

So although the GFS 06Z has raised the blood-pressure and caused some on here to cry "Game Over", my current thinking is that the easterly is probably still on, though depth of cold is still well up for debate. Looking at the ensemble mean for T850s, I'm guessing there will be members in the showing anything from 0C in the South West to -10C on the east coast - so too early to be certain of that one.

 

But these situations (Atlantic vs Easterly battle), considering it is January, usually involve a precipitation bearing front dividing the cold and the less cold, with the cold side having snow, the milder side having rain, but if it stays in situ for a while more and more of the front gets undercut by the cold and eventually more and more places have snow. Leaving out the extreme runs of the GFS, the front surely will be somewhere over the UK, perhaps North England/Southern Scotland being favoured on the latest charts. But that's a really crude prediction - best for now to say, at T144, the snowline somewhere between the Shetlands and the M4, edging south and west with time.

 

So uncertainly, yes, but not as much uncertainty as some are making out today. Final note - if the block to the north doesn't happen, the ECM mean is going to look pretty ridiculous even at T120 - it's happened but very, very, very rare that the ECM mean is that wrong at that short a range. I think it won't be far off.  

[tight isobar]

It might be drifting away way folks - 15 years of experience watching these events come and go and the rule of thumb is.

 

1) Cold spell shows up on a couple of runs - Last Weekend Runs.

2) Cold spell shows up on remaining runs -  This Monday Runs.

3) It slowly improves or stays stable - This Tuesday Runs.

4) We get a boom set of charts - This Wednesday mornings runs

5) Next set of charts maintain the theme - This Wednesday evening runs

6) Runs back off - still look ok, but not as good.. This mornings runs.

7) Run continue to back off. Tonights runs.

 

I believe we are at step 6, lets see how step 7 pans out, if it happens then its off....in my humble view.

 

We never got to steps 6 or 7 when cold spells have delivered AKA 2009 / 2010 / 2013

 

Fingers crossed for the 12Z's - The crowds will soon be rocking up

this post only serves to highlight 12z importance of today any further backtracking cross or big 3 ECM, GFS, UKMO.then a watered down cold blip maybe our climax. Get an upgrade or then mid/longerterm pprognosis needs serious consideration. Stall to around where the 6z cross model (example) its no mans land atm IMO

[lassie23]

GEM has bitterly cold easterly, GFS easterly being pushed further back, ECM brings eventual easterly, who will be right?

[Frosty.]

Holy Cow..this is snow joke guys, the Ecm 00z ensemble mean is FAB-U-LUS. absolute snow fest with ice days galore from this, heck I need a lie down now If this carries on, I might have to ramp this up

I would like to see the Ecm step up to the plate and deliver for once when the majority of us most need it, it's been a rubbish winter so far but the Ecm 00z ensemble mean screams potential with a blocking high forming to the northeast and low pressure undercut, I keep reading how much better the ecm is and how rubbish the gfs is, well come on ecm, deliver the goods for once!! Bring us the undercut we need for a much colder and frosty outlook with snow events during the coming weeks. I posted the charts earlier..take a look if you like

Edited January 9, 2014 by Frosty.

[The Eagle]

It might be drifting away way folks - 15 years of experience watching these events come and go and the rule of thumb is.

 

1) Cold spell shows up on a couple of runs - Last Weekend Runs.

2) Cold spell shows up on remaining runs -  This Monday Runs.

3) It slowly improves or stays stable - This Tuesday Runs.

4) We get a boom set of charts - This Wednesday mornings runs

5) Next set of charts maintain the theme - This Wednesday evening runs

6) Runs back off - still look ok, but not as good.. This mornings runs.

7) Run continue to back off. Tonights runs.

 

I believe we are at step 6, lets see how step 7 pans out, if it happens then its off....in my humble view.

 

We never got to steps 6 or 7 when cold spells have delivered AKA 2009 / 2010 / 2013

 

Fingers crossed for the 12Z's - The crowds will soon be rocking up

 

 

 

The monthly 6 stage loop the loop rollercoaster for model watchers:

 

1. Calm

2. Cautious                               *Upgrades before 240 hrs

3. Estatic

 

4. Denial

5. Anger                                    *Downgrades before 144 hrs

6. Acceptance

 

In stage 4 I reckon.

 

Still plenty of time for upgrades.

Edited January 9, 2014 by The Eagle

[legritter]

The middle of next week is realy a hard call lets say late wed early thursday .there is every possibility of disruptive rains over a good portion of the uk ,and with most probably with colder uppers trying to push in from the  n /east a forecasters nightmare could present it self .so i find todays Met update about right for looking at that range ,tomorrow and this weekend could present the forecasters with a totally different set of model options ,its all about being patient as every day will see a change .the met office are in control of themselves where as Express will get it right from time to time .Great posts today on a very interesting forum .cheers .