Model output discussion 25th Jan onwards

[Captain Shortwave]

Only the ECM can show a south westerly from the Carribean and then on the next run have a bracing easterly straight from Siberia.

Look at that cold heading our way 

 

Strangely the ECM is poorest during the mid-range, failing to develop cut off heights over Iceland and relies on some very dubious amplification which looks much higher risk than a small chunk of heights shown on the UKMO/GEM and to an extent GFS which can link with heights over Svalbard.  

Edited February 12, 2014 by Captain shortwave

[Polar Maritime]

Nice to see ECMWF showing signs of a change, 

 

 

Come on GFS you can do it ! It's trying at least...

 

 

GEM

 

Edited February 12, 2014 by Polar Maritime

[legritter]

Only the ECM can show a south westerly from the Carribean and then on the next run have a bracing easterly straight from Siberia.

Look at that cold heading our way 

Well said Captain ,plenty in the charts to keep us glued ,certainly no let up on the horizon unless later ecm frames verify ,and then another possible hazard  SNOW ,looks like a very interesting model output to come .

[TEITS]

I would love to see the faces of those waking up to the ECM this morning.

 

HP over the UK linking up with HP extending S from Svalbard.

 

http://www.wetterzentrale.de/pics/Recm1681.gif

 

http://www.wetterzentrale.de/pics/Recm1921.gif

 

Link up complete and note the incredible surge of cold spreading S.

 

http://www.wetterzentrale.de/pics/Recm2161.gif

 

Beyond +240 if this run was to verify the orientation of the HP would tilt slightly W-E rather than N-S. This would mean the incredible cold would start backing W. This is the kind of synoptic set up that is rare and where -20C upper temps can reach the SE.

[Man With Beard]

I would love to see the faces of those waking up to the ECM this morning. HP over the UK linking up with HP extending S from Svalbard. http://www.wetterzentrale.de/pics/Recm1681.gif http://www.wetterzentrale.de/pics/Recm1921.gif Link up complete and note the incredible surge of cold spreading S. http://www.wetterzentrale.de/pics/Recm2161.gif Beyond +240 if this run was to verify the orientation of the HP would tilt slightly W-E rather than N-S. This would mean the incredible cold would start backing W. This is the kind of synoptic set up that is rare and where -20C upper temps can reach the SE.

This, you feel, is a critical moment of the winter. If the charts above gather some consistency is the next 2 days, we may yet get a genuine cold spell this month. But still could go either way at this stage.

[Downpour]

Crikey. Had to get up very early this morning to take my four year old son to nursery. Needless to say I won't be mentioning the charts to him. Epic is the only word.

Once, just once, can this be right?

[bluearmy]

well it hasn't come 'out of the blue' but it remains so unsupported by the ens in general that it really shouldn't get too much attention. And yet, it does seem plausible, given recent days op output.

eyes down for the ECM ens (which should offer some support as they ususally do tend to follow the op) and then the gefs through the day. We have seen a general propensity to raise a ridge in the ens but the upstream profile has generally flattened it.

[Severe Siberian icy blast]

Amongst the upgrades this morning , which the models have been hinting at for quite some time , especially as the 0'z this year have tended to be the set to bring us all crashing back to earth with a bump , this I feel has to be a very good sign .

Nobody has mentioned this possible snow event either at a much more reliable time frame .

Given the colder air in place and cold air sucking quickly in behind it there may be a genuine case for a snow event on its northern flank . Gfs has this low further north and a bit too flabby to bring anything , whereas the ECM keeps it clean .

Not too mention this evening and tonight is going to be a very snowy night for the higher ground of northern England , and various streamers further south feeding consistent wintry showers , things are definitely beginning to get interesting . It's the 12 feb today so we have a good 5 weeks left available to receive disruptive snow with the right Synoptics . So all is not lost folks

[Troubleatmill]

ECM has latched on to what a number of GEFS members and operationals were playing with a number of days ago, think Mucka anf TEITS also mentioned it,although it has to be said that at that point the ECM couldnt as they were out beyond t240. great charts although there are a number of different outcomes from where we are today, so still very much tentitive hopes at this point

Edited February 12, 2014 by Nicholas B

[IDO]

Three GEFS at T192 are close enough to the ECM at the same time frame to be a cluster but at the moment the majority stay with the Atlantic flow, mean:

 

 

Bt T240 there are four Scandi Highs and a couple Atlantic Ridges, so more synoptic scatter than of late, and maybe a prelude to a pattern change (taking the other models on board)?

 

Bt D16 the GEFS are showing the PV more organised and depending on what happened in the upcoming lull we are either facing more of the same, MLB or some colder charts:

 

  

 

 

 

So no conclusions yet but certainly slightly lower confidence in the maintenance of the current pattern, though still favourite, as the London ens highlight (cold still seemingly at a premium): 

 

[Severe Siberian icy blast]

Very good GEM this morning also. With almost all models showing similar Synoptics just variations of the same thing really surely this has to be a trend . You can't have every model barking up the wrong tree can we?

Meh !

[Troubleatmill]

Very good GEM this morning also. With almost all models showing similar Synoptics just variations of the same thing really surely this has to be a trend . You can't have every model barking up the wrong tree can we?

image.jpg

Meh !

Think you know the answer to that one already bud? Lets hope not though, ensembles from the GEFS are hardly inspiring at this point however

[johnholmes]

Great ukmo & Gem this morning,Superseeded by an even more Epic ECMPlease just for once this winter let an ECM run verify-Note the link up- uk/iceland ridge to the svalbard highHigh risk manoevre though.....S

 

 

yes your chart is there Steve, this time ECMWF being the leader. It would be unfair for me not to say it is not what I would expect to verify using the anomaly charts. That said they are not infallible so an interesting few days from 144h down. Certainly the NOAA outputs did not suggest anything like it last evening so be interesting to see the EC-GFS version for 6-10 days this morning.

I've just downloaded EC-GFS and sure enough they both show some kind of upper ridge where for days they have shown nothing like it. I have also downloaded the 240h EC and will when I get time post a pdf of the conflicting charts from anomaly and synoptic. Highly interesting over the next 2-3 days to see how things turn out whatever the outcome in terms of actual weather.

Edited February 12, 2014 by johnholmes

[Jason M]

well it hasn't come 'out of the blue' but it remains so unsupported by the ens in general that it really shouldn't get too much attention. And yet, it does seem plausible, given recent days op output.eyes down for the ECM ens (which should offer some support as they ususally do tend to follow the op) and then the gefs through the day. We have seen a general propensity to raise a ridge in the ens but the upstream profile has generally flattened it.

Having looked through all the models this morning they seem to largely agree at 120 and 144 so at that range it makes sense to back the opp runs. The ECM opp in the longer term looks like a Feb 91 sort of event and is therefore extremely unlikely simply because it's the sort of thing we see in the models every year, but only verifies every 20 years or so! More likely we would develop a separate high pressure cell over the uk or the sheer depth of cold would lead to the dreaded shortwave development with the whole lot ending up over Greece.As you say, very low confidence at this point in anything major and I won't be telling my kids ;-)

[Frosty.]

Fab-U-Lus 00z output this morning for cold and snow potential and even today there is snow in parts of the uk, upland areas could be buried under a deep blanket of snow with blizzards across higher parts of scotland and the pennines expect blizzards tonight..then the weekend could be cold and wintry with snow in places and frost / ice...and then look at the end of the Ecm 00z  this will give the experts plenty to chew over

[TEITS]

yes your chart is there Steve, this time ECMWF being the leader. It would be unfair for me not to say it is not what I would expect to verify using the anomaly charts. That said they are not infallible so an interesting few days from 144h down. Certainly the NOAA outputs did not suggest anything like it last evening so be interesting to see the EC-GFS version for 6-10 days this morning.

I've just downloaded EC-GFS and sure enough they both show some kind of upper ridge where for days they have shown nothing like it. I have also downloaded the 240h EC and will when I get time post a pdf of the conflicting charts from anomaly and synoptic. Highly interesting over the next 2-3 days to see how things turn out whatever the outcome in terms of actual weather.

No model output is infallible. This is why it is wise to use forecasting instinct alongside computers when looking at the medium/long range.

 

A good example of over reliance of models is what occurred many years ago when I first joined this forum. A band of snow was hitting the N Midlands and a forecaster on this site (won't embarrass them) said the band of snow will move to SE England because the models said so. However the radar said otherwise and suggested SW. The reality was SW England were hit and the SE remained dry.

 

Over dependance on computers is something that occurs all the time not just in weather forecasting!

[MR EXTREMES]

Great ukmo & Gem this morning,Superseeded by an even more Epic ECMPlease just for once this winter let an ECM run verify-Note the link up- uk/iceland ridge to the svalbard highHigh risk manoevre though.....S

as i said yeasterday its coming you just know its coming why the pattern is changing and moving there is noway the vortex is going to go on foreve the strat events and a weakening jet were always going to favour better outputs towards the end of feb.

 

im very bullish in saying that a spring 2013 repeat looks pretty good.

of coarse more runs needed but this has been a few days now they will of coarse toy with ideas but the alantic onslaught looks to be slowing there for allowing some decent ridging to esablish its self remember the last scandi block it stuck around for atleast two weeks or more we were unlucky but this time round its more favourable.

as i said yeasterday its coming you just know its coming why the pattern is changing and moving there is noway the vortex is going to go on foreve the strat events and a weakening jet were always going to favour better outputs towards the end of feb.

 

im very bullish in saying that a spring 2013 repeat looks pretty good.

of coarse more runs needed but this has been a few days now they will of coarse toy with ideas but the alantic onslaught looks to be slowing there for allowing some decent ridging to esablish its self remember the last scandi block it stuck around for atleast two weeks or more we were unlucky but this time round its more favourable.

ding ding round 3 lol.

[weather eater]

Well it’s a case of stick or twist with the ridge this morning. Any cold lover myself included will love the ECM, but how will change and evolve over the coming days, can it change for the better or is it just another red herring. Personally I doubt the ECM when it comes to easterlies, but if I’m wrong I will still enjoy my humble pie. Best case scenario the ECM is close, Second best, we get some sort of dryer interlude. The worst case, something like the GFS, which although not bad snow wise for some at times, will just heap more misery on the flooded south.

Edited February 12, 2014 by weather eater

[Gibby]

Good morning folks. Here is today's look at the midnight outputs as I see them from the NWP for this morning Wednesday February 12th 2014 and taken from my website at http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

 

All models illustrate a very volatile weather pattern between now and the end of the weekend as all models show two separate storm systems crossing NE over Ireland and the North through this period. As a result winds will become very strong with gales and severe gales likely later today and again later on Friday and overnight. In addition a spell of very heavy rain will sweep NE across the UK today and again on Friday afternoon with clearer, colder and very showery weather at other times when some snow could fall over the hills and at least some moderation of the wind would likely occur.

 

Then next week GFS shows unsettled weather maintained as further Low pressure slip ESE across the South and then all of the UK by midweek with yet more copious rain events for many and some snow likely in the North where it will be colder. The rest of the run settles into a changeable Westerly weather type between Low pressure areas crossing East to the North and High pressure to the South. Troughs would continue to cross East in the strong Westerly flow with the heaviest rain in the North and West with some showery interludes in between. Temperatures would become close to or perhaps a little above average across the South at times.

 

UKMO shows Tuesday being cold with a filling Low across Southern Britain with rain and showers scattered about falling as sleet or snow over the hills. Precipitation would be less widespread than on previous days though under light winds.

 

GEM builds pressure to the North of Scandinavia strongly this morning with cold Continental air moving in on the back end of depressions slipping slowly SE across NW Europe. This would increase the potential for sleet or snow for a time in temperatures much lower than anything we have seen thus far this year though on this run it appears temporary as by Day 10 the Atlantic wind and fronts push the cold back north and East in attendance of rainfall.

 

NAVGEM anchores Low pressure across Northern Europe the UK and the Eastern Atlantic maintaining a windy and unsettled theme with spells of rain and showers on a mostly Westerly flow. Some snow could occur on northern hills at times.

 

ECM today shows an interesting solution which also like GEM leads to a very cold Easterly late in the run as pressure rises over Britain midweek giving a 48hr of dry weather for the SW. Pressure then becomes very high North of Scandinavia with Low pressure slipped down over Europe leading to disrupting troughs near the SW of Britain bring yet more rain late in the week here with snow over the moors while Eastern areas see a cold feed from Europe bringing with it the risk of snow showers and much colder weather.

 

The ECM 7 to 10 Day Mean Charts this morning are resilient to any significant change from the pattern they have shown over recent days in as much that Low pressure lies South of Iceland and High pressure near the Azores with the Jet flow to the South of the UK maintaining a preference to keep the UK under relatively mild Westerly winds with rain at times, heaviest towards the NW. There must be scant support for any High pressure North of Scandinavia within the pack as pressure there is shown to average no higher than 1010-1015mbs.

 

http://www.wetterzentrale.de/pics/Reem1681.gif

 

http://www.wetterzentrale.de/pics/Reem1921.gif

 

http://www.wetterzentrale.de/pics/Reem2161.gif

 

http://www.wetterzentrale.de/pics/Reem2401.gif 

 

The GFS Ensembles are not very supportive of the colder evolutions mentioned above with a trend of fairly average value temperatures looking likely with rain at times though less in amounts than recent times.

 

http://www.null/two/ensembles/

 

The GFS Jet Stream Forecast shows and reflects it's main member outputs this morning in keeping the Jet flow either over or still to the South of the UK maintaining the formation of deep Low pressure centres over or to the North of Britain as it drifts a couple of hundred miles further North than currently later in the run.

 

In Summary this morning the output is once more becoming very fascinating viewing as the models jostle around with various solutions to get us out of the current rut of Atlantic depression after Atlantic depressions crossing the UK. On the one hand we have GFS and NAVGEM who both show an unrelenting Atlantic dominated pattern with further Low pressure areas keeping the basic wet and windy theme going while UKMO, GEM and ECM show in my opinion a strong chance that we could have a switch to a more Continental dominated pattern at least for a time. In the case of the charts shown specifics for next week should this verify are unimportant at the moment and would change run to run. It is a dangerous course of synoptics to undergo though as it could swing the pendulum one of two ways for the flood stricken folks in the South. If the Easterly feed is allowed to take hold it could at long last make for some useful dry weather to at least drain some of the flooding away while on the other hand with a cold block to the NE we run the risk of Low pressure ramming into the block over what could be a UK battleground with further heavy rainfall or indeed snowfall in those areas that least need it. We will have to see how this dangerous pattern develops over subsequent runs if at all and to see whether it gains support from other models and indeed their own ensembles.

[winterof79]

Fab-U-Lus 00z output this morning for cold and snow potential and even today there is snow in parts of the uk, upland areas could be buried under a deep blanket of snow with blizzards across higher parts of scotland and the pennines expect blizzards tonight..then the weekend could be cold and wintry with snow in places and frost / ice...and then look at the end of the Ecm 00z  this will give the experts plenty to chew over

Agreed Frosty,

Subtle changes in the METS medium term outlook.

" Towards the end of February the changeable weather looks set to continue, but with longer drier and brighter periods between bouts of rain and wind. As a result it may turn colder with an enhanced frost and ice risk."Nice to see thunder snow here last evening too.

I for one would be happy with a sudden u-turn in their assesment for obvious reasons.

[Mucka]

So here we go again, last call for the Siberian express, all aboard?

 

Before that though the member Severe Siberian icy blast has rightly mentioned a possible snow event in the much earlier time-frame and I have to agree, the 17th/18th looks like a good date for widespread snowfall though hard to say how far North/South any snowline might be. The Euros  have a fairly clean Northerly as Saturday's low  moves away into Scandinavia which pulls enough polar air across the UK for snow when the programmed slider  moves in behind on the 17th - though GFS is not as keen.

The brief Northerly looks a fairly good bet though it is hard to know how much and how far South any cold air will get before the slider moves in. The slider itself now also looks very likely but the timing and depth of this feature and how it interacts with the colder air will mean MBY snow chances will likely ebb and flow down to the last day.

 

After that event there is much uncertainty re the ridge behind. How strong will it be? Can it link up with the Arctic high? Will we get the undercut behind?

Nobody knows which is what makes the model output such fascinating viewing for weather geeks.

All we can do is weigh the balance of probability between outcomes with the limited information we have and in the knowledge that information will change/update through every day - we have all been humbled at one time or another by the vagaries of our weather, usually just when we thought we had this model stuff nailed.

 

From here I will personally have one eye on how clean that brief Northerly is and how the slider develops and another on the potential of the ridge behind.

It has been long old slog this Winter but will finally get a late winter treat? 

Edited February 12, 2014 by Mucka

[weather eater]

No model output is infallible. This is why it is wise to use forecasting instinct alongside computers when looking at the medium/long range.

 

 

Indeed Dave but by the same token forecasters are not infallible either, that’s been shown on this forum many times over the years by people allowing their hearts to rule their heads and it applies to those with lots of knowledge and to those with a much more modest amount, I include myself in that. When it comes to forecasting in the mid to longer range, a wise head is a sceptical head, I’ll start clapping when the fat lady is in the auditorium and about to come on stage.

[MR EXTREMES]

No model output is infallible. This is why it is wise to use forecasting instinct alongside computers when looking at the medium/long range.

 

A good example of over reliance of models is what occurred many years ago when I first joined this forum. A band of snow was hitting the N Midlands and a forecaster on this site (won't embarrass them) said the band of snow will move to SE England because the models said so. However the radar said otherwise and suggested SW. The reality was SW England were hit and the SE remained dry.

 

Over dependance on computers is something that occurs all the time not just in weather forecasting!

this also happens alot every winter mostly 09/10 winter had lots of events that were last minute.

[TEITS]

Indeed Dave but by the same token forecasters are not infallible either, that’s been shown on this forum many times over the years by people allowing their hearts to rule their heads and it applies to those with lots of knowledge and to those with a much more modest amount, I include myself in that. When it comes to forecasting in the mid to longer range, a wise head is a sceptical head, I’ll start clapping when the fat lady is in the auditorium and about to come on stage.

Yes must admit over the years my biased towards cold has always affected my judgement of the model output although in recent times I have moderated this.

 

One concerning aspect if a bitter E,ly should occur is ice especially if the floods do not drain away in time. Shame I cannot play Ice hockey anymore otherwise I could of played a match on the River Nene here.

[MR EXTREMES]

t144 is were the changes are expected to happen so up until this time is were we need to watch for future developements,

the gem jma ukmo and ecm have very much like for like charts thats pretty good cross model agreement up until t144.

 

the gfs is a model id look at up until t96 always.

it rather frustrates me with its redbull evolutions.