Model Output Discussion - 10th Jan Onwards

[BlueHedgehog074]

I'm probably likely to be incorrect on my assessment here, but the 00Z UKMO chart seems to offer a little bit of future Low undercutting potential, where it's blocking to the North-East on that model looks quite prominent and could possibly help that approaching Low out West could disrupt some of its 'energy' South-East or East.

 

The black arrows on the UKMO chart shows a solution that could happen. (If some of that Low Pressure out West does slide underneath the block, that Scandinavian High could then attempt to back a little bit further West - solution shown by the arrows):

 

Two possible problems I can see with this however, is that the Low does look fairly orb shaped (not usually a good sign if you want a Low to cleanly slide underneath a block to the North-East). And some of that ridging to our South (shown by a black circle on the same chart again underneath) could try and link up with the block to the North and North-East creating an obstacle for that Low Pressure to try slide properly underneath the block.

 

Again, admiitedly, I'm probably looking at this in too much of a wishful way hoping that the Low out West will disrupt favourably to somehow try and reinforce that block to our North-East on that chart.

 

Apart from this, it does look like the Atlantic may try coming crashing back in eventually as the tiger of the Polar Vortex tries to break back out of its cage sending a more mobile, Westerly, flow back over us - the block to the North-East probably likely to make less and less influence within the next week or so. Still, the look of that 144 hour 00Z UKMO chart does make me wonder what it would have looked liked at 168 hours. Perhaps if the UKMO 12Z looks similar (and I imagine it's probably starting to come out around now), then it could start becoming more intersting again for cold, blocking solutions. But as I said earlier, I'm probably just putting too much faith into this.

[Alexis]

Yes, the UKMO 12z keeps the undercutting at 144h.

 

Let's see if the ECM follows suit and gives us hints of what could be next.

[Paul]

I could be totally brutal and say perhaps some of you may now begin to see the folly of watching the synoptic models for the weather without checking on other outputs. Hurtful no doubt but true. I could show you every single output from Ec-gfs and noaa 500mb anomaly charts for the last 10 -15 days if you like to prove my point. On only ONE day, 5 January did ec not gfs and noaa did show the 'possibility' of a Sacndinavian block possibility. Nothing before and nothing since. Why do you think Exeter never went for it, I have no idea if they use the anomaly charts but they must have seen how isolated the risk was from whatever their sources thus never went for it. Loud cries on here that they were wrong and they would change because of the synoptic outputs etc.

Like I say it is a harsh comment for you and others but it is true. No major upper air pattern except for that one day ever seriously suggested an easterly.

Yes I got sucked in to the extent I went from sitting on the fence with a prob of no more than 40% to on the one day being totally over ruled by my heart (I am a snow lover) and edging it above 50%, but then brain took over and I dropped the idea.

 

Agree to an extent, but when you say that the meto never went for it, they never went for it publicly because it was low confidence, we know though that they discussed it, saw the possibility and new it was a potential risk for a time, which essentially is what happened in here. Ok it won't have been discussed in the same way obviously, but this being an open discussion forum you'd never expect it to be. 

 

I think there's a fine line between getting carried away with something showing in the models and running with it before it's even close to nailed down, and discussing it with a bit of enthusiasm - yep of course some people jump on bandwagons at times, some people see a cold run at t+240 and start polishing the sledge only to see it disappear next run. And some of those people will then go on to blame bad models, dodgy forecasts and so on when that happens, rather than facing up to reality that is forecasting weather is hard, forecasting models are all going to lead us up the garden path from time to time, so being pragmatic about them and using as much info as possible is the way forward. But hopefully for every person who falls foul of that trap, there are 10 who learn about it!

 

I guess all I'm trying to say is that discussion is good, different ideas and styles are good even when some of those ideas and styles are wide of the mark we can still all learn from it, and enjoy the discussion at the same time.

[nick sussex]

So the trough drama continues with the UKMO now very close to some snow with a possible undercut, the GFS 12hrs  is an improvement on the GFS 06hrs run but as we can see the models are making  a longwinded saga out of this troughing and how it phases with energy to the nw.

 

Until this troughing is sorted out then its impossible to say what will happen next because if the upstream pattern is more amplified the  next incoming low may just disrupt keeping the UK in colder conditions.

 

I'm sure there will be more changes because the models show no sign of coming to agreement anytime soon on this.

[mcweather]

I could be totally brutal and say perhaps some of you may now begin to see the folly of watching the synoptic models for the weather without checking on other outputs. Hurtful no doubt but true. I could show you every single output from Ec-gfs and noaa 500mb anomaly charts for the last 10 -15 days if you like to prove my point. On only ONE day, 5 January did ec suggest this along with noaa, but not gfs, that is  the 'possibility' of a Scandinavian block. Nothing before and nothing since. Why do you think Exeter never went for it, I have no idea if they use the anomaly charts but they must have seen how isolated the risk was from whatever their sources thus never went for it. Loud cries on here that they were wrong and they would change because of the synoptic outputs etc.

Like I say it is a harsh comment for you and others but it is true. No major upper air pattern except for that one day ever seriously suggested an easterly.

Yes I got sucked in to the extent I went from sitting on the fence with a prob of no more than 40% to on the one day being totally over ruled by my heart (I am a snow lover) and edging it above 50%, but then brain took over and I dropped the idea.

 

Hi John

 

Its is a reasonable point that you have raised there.

 

but here's another one that a newbie on here might legitmately raise. 

 

If the 500mb charts only suggested the possibility of Scandinavian blocking on just one day, how come the operational runs from synoptic models created and run by professional meteorologists continued to show such blocking as a  possibilty for a darn sight longer, surely the two can't be that disconnected can they?

Edited January 15, 2014 by mcweather

[That ECM]

I could be totally brutal and say perhaps some of you may now begin to see the folly of watching the synoptic models for the weather without checking on other outputs. Hurtful no doubt but true. I could show you every single output from Ec-gfs and noaa 500mb anomaly charts for the last 10 -15 days if you like to prove my point. On only ONE day, 5 January did ec suggest this along with noaa, but not gfs, that is  the 'possibility' of a Scandinavian block. Nothing before and nothing since. Why do you think Exeter never went for it, I have no idea if they use the anomaly charts but they must have seen how isolated the risk was from whatever their sources thus never went for it. Loud cries on here that they were wrong and they would change because of the synoptic outputs etc.Like I say it is a harsh comment for you and others but it is true. No major upper air pattern except for that one day ever seriously suggested an easterly.Yes I got sucked in to the extent I went from sitting on the fence with a prob of no more than 40% to on the one day being totally over ruled by my heart (I am a snow lover) and edging it above 50%, but then brain took over and I dropped the idea.

Wouldn't want to disagree but this thread would need to close if we did most of what you say. Part of the fun of this thread is look at each run and discuss. A lot can be learnt. With experience you know not to take to much at face value until T 72 at the most.

[johnholmes]

Hi John

 

Its is a reasonable point that you have raised there.

 

but here's another one that a newbie on here might legitmately raise. 

 

If the 500mb charts only suggested the possibility of Scandinavian blocking on just one day, how come the operational runs from synoptic models created and run by professional meteorologists continued to show such blocking as a  possibilty for a darn sight longer, surely the two can't be that disconnected can they?

 

I wish I could give you an answer but I honestly do not know.

Perhaps Jo as a professional forecaster and still forecasting may be able to answer that one?

 

I would love to get to Exeter and chat with the forecast watch there to get a more up to date 'feel' for how things are looked at. When I retired it was still very much the Met O output mostly for 72-96 hours with then an increasing input from the Euro model, no GFS at all. Nothing went beyond 144h in any forecast we issued in those days. That is after the withdawal of the monthly outlook some years previously.

[mcweather]

I wish I could give you an answer but I honestly do not know.

Perhaps Jo as a professional forecaster and still forecasting may be able to answer that one?

 

I would love to get to Exeter and chat with the forecast watch there to get a more up to date 'feel' for how things are looked at. When I retired it was still very much the Met O output mostly for 72-96 hours with then an increasing input from the Euro model, no GFS at all. Nothing went beyond 144h in any forecast we issued in those days. That is after the withdawal of the monthly outlook some years previously.

 

Thanks for your answer John.

 

Its is a truly fascinating subject this model watching.

[snowmadchrisuk]

Well looking at the 12z , the encouraging signs are the PV stays mainly West of Greenland, When it does decide to try and come further East , it is South East , High pressure lobe staying around Greenland area , and Low pressure getting further and further South into Europe , Jet stream is also Tilted NW/SE , Would say plenty of Chance of some NW flow based Wintry showers, why we await the good stuff. 

[Timmytour]

I believe things are falling into shape gradually and the models will increasingly show us the way into a cold spell beginning sunday/monday.

T132 holds the key for me in the GFS 12z....there's a little less movement east across the Atlantic and colder air coming down into Siberia

 

I'm optimistic that, as tick becomes tock and T132 becomes T129, T126, and T123 on future runs, it will develop into the prospect of a cold easterly blowing its way towards us at T120

Then it will all go bosoms up!

[Man With Beard]

Why oh why are there not more comments on the UKMO, once again!! IMO it has shown itself this winter as the most reliable chart for the UK, and look at what it is showing! Heights pushing back west towards Greenland and troughing angled in an "I'm thinking about sliding under the high" kind of way, all the way from T72 to T144. It is on the edge of actually being wintry, in fact for the north it probably is! A continuation of yesterday's 12Z.

[johnholmes]

It certainly is and please those who may feel aggrieved at my earlier post that I am anti enjoyment or discussion in the model thread. Not at all. I would just like to get new folk to realise that there is a heck of a lot more to getting a forecast correct that just looking for what you want and switching from model to model to get the pattern you hope for.

There are certain sensible guidelines to follow, same time output down to 144h and only trends beyond about 168h, continuity between models, also try to understand some of the other links, upper air patterns, things like MJO, AO, NAO but read up on them to try and get a real feel/understanding for them. The Stratosphere thread is beyond me but is another fascinating part of meteorology. Never dismiss anything but see how it fits in to the overall outputs.

Above all do enjoy the weather in all its forms in this country, don't be put off by kill joys like me. Ex anyone can be a pain in the neck and ex forecasters are no different. I've said it many times but it is true, I am constantly amazed at the depth of knowledge shown on here from those who have had no professional training.

 

Finally have a look on Extra if you have it and 'play' the 12z through with surface and 500mb data on it. Note how the marked trough so much in the chat on here behaves, or rather how GFS deals with it. Never moving much in terms of longitude but extending south into N Africa. Only moving when an upstream upper ridge with its attendant surface low pressure moves east. Someone asked if the two surface features north of the one that runs into the southern end of the trough might not pull those two down with it. I think that doubtful because they appear, if you look at the upper air, to be out of the main flow thus will simply drift around tending to fill with time. That is until the main upper trough is moved east and tends to warm out as the next upper ridge and surface low move east.

yes, fascinating stuff.

Edited January 15, 2014 by johnholmes

[swfc]

Why oh why are there not more comments on the UKMO, once again!! IMO it has shown itself this winter as the most reliable chart for the UK, and look at what it is showing! Heights pushing back west towards Greenland and troughing angled in an "I'm thinking about sliding under the high" kind of way, all the way from T72 to T144. It is on the edge of actually being wintry, in fact for the north it probably is! A continuation of yesterday's 12Z.

It does look ok but imo the low will push threw due to the ridge behind it.when is the next run due out on the ukmo.thanks

[draztik]

Why oh why are there not more comments on the UKMO, once again!! IMO it has shown itself this winter as the most reliable chart for the UK, and look at what it is showing! Heights pushing back west towards Greenland and troughing angled in an "I'm thinking about sliding under the high" kind of way, all the way from T72 to T144. It is on the edge of actually being wintry, in fact for the north it probably is! A continuation of yesterday's 12Z.

think many have model fatigue atm, with the models teasing only to revert with their next runs. There has been very little consistency at present, which creates hopes only to dash them.

[Severe Siberian icy blast]

Why oh why are there not more comments on the UKMO, once again!! IMO it has shown itself this winter as the most reliable chart for the UK, and look at what it is showing! Heights pushing back west towards Greenland and troughing angled in an "I'm thinking about sliding under the high" kind of way, all the way from T72 to T144. It is on the edge of actually being wintry, in fact for the north it probably is! A continuation of yesterday's 12Z.

Well I'm having trouble viewing the 12 on meteociel for some reason , it's playing up as it flippin always does, but from what Iv seen yes it looks actually quite good , The scandi high starts retrogressing west somewhat as soon as t96 , and everything does look as if it wants to go under , the scandi high certainly is causing a few issues as usual , by t144 it looks like at least some of the energy is about to go under , but the same old issue hear is the fact that Europe is still mild , so not sure how low due points will be , our uppers of -3 or so would be fine , if we have cold due points to draw from France . Let's wait an see Edited January 15, 2014 by Severe Siberian icy blast

[Man With Beard]

think many have model fatigue atm, with the models teasing only to revert with their next runs. There has been very little consistency at present, which creates hopes only to dash them.

If it had been the GFS or ECM, sure. The thing is, if we'd only had the UKMO this winter, we would have had very few "cry wolf" events from the models, so when the UKMO shows something interesting I sit up! I accept all the UKMO charts from T72 to T144 are not "stella" due to lack of cold on the continent, and yes where would it go from T144, a little extra height building to the north maybe needed, but as they are they aren't a long way from drawing enough cold into northern areas for snow, and it wouldn't be dry either. Oh well, the weather will do what it will! Just thought the charts needed flagging up, why does the GFS get all the attention!

[Cecil Hogmanay Melchett]

Cant see much to be excited about on any of the 12z output hand on heart.

UKMO just looks cold and wet to me with pressure starting to build across Southern Europe.

Its better than gfs but isn't going anywhere particularly winter imo.

[WhiteFox]

 

that Low of north western Spain is a new feature..... 

 

It's been on there for a few days. Up until recently it has been shown as a shallower feature, but it has been there:

 

 

 

 

Not sure that it will make much difference though!

[nick sussex]

Just reading some comments from NCEP, they expect troughing to remain over the eastern USA and for shortwaves to drop south and then east into the Atlantic.

 

The engagement point of those shortwaves with the upstream troughing is important, take a look at the UKMO from T96hrs in NH mode to see the effect this has on the PV chunk, of course if the pattern is more amplified these will pull the PV that bit further to the nw and may help to sharpen troughing near the UK.

[supernova]

If it had been the GFS or ECM, sure. The thing is, if we'd only had the UKMO this winter, we would have had very few "cry wolf" events from the models, so when the UKMO shows something interesting I sit up!

I accept all the UKMO charts from T72 to T144 are not "stella" due to lack of cold on the continent, and yes where would it go from T144, a little extra height building to the north maybe needed, but as they are they aren't a long way from drawing enough cold into northern areas for snow, and it wouldn't be dry either. Oh well, the weather will do what it will! Just thought the charts needed flagging up, why does the GFS get all the attention!

Fair point, this is no phantom ECM Easterly at 192hrs+ this is an oh so close undercut on the near edge of reliable from this winter's top performing model, in the face of a complex trough scenario which could go either way as Nick Sussex and others have so succinctly pointed out . I think the biggest problem is not so much what the models are showing but the fact that we're all a bit model fatigued and Frosty isn't posting UKMO charts next to tins of Carlsberg to keep us all positive! So Frosty, this is for you, let's hope the UKMO….

can pull a rabbit out of the hat...

[OldMetMan]

No doubt many would disagree, but I am finding current model output fascinating, as it continues to tease with hints of a colder continental flow. Yes, it is also frustrating, looking for some development that might clinch the deal, so to speak, but so far, nothing is there that qualifies, I think.

 

However, there are still some promising signs, if not within the current model timeframe, but for later this winter. But for now, I am still intrigued by the changes occurring at 500mb, especially upstream:

 

:

 

First that mid-Pacific troughing is still amplifying - a little - whilst the E Pacific ridge looks a lot stronger than it did. Downstream, the trough over the E US/Canada has certainly amplified a good bit.

 

But I am still watching that persistent upper high off NW Scandinavia, plus the ridge way off to the SW of it. As it looks now, it would seem to take very little to join up these two features, to form a really solid SW/NE block across the W Atlantic, whilst our own upper vortex to the W sinks away SE. This, in my view, would certainly allow the cold air floodgates to open, as troughing extends SW out of N Europe.

 

Yet again, we have that fearsome jet to take into account, plus the overall hemispheric flow which remains pretty potent. Just a bit more troughing off the N American E coast and a slow down in the flow, that to my mind would be a clincher.

 

After the preceding weeks, it seems as if any chance of that happening is remote, in the model timeframe at least. But not impossible I would say. The model output has continued to be vague as to what will happen to our 500mb vortex, and what will follow. Inevitably, the GFS launches straight back into zonality, as it likes to, but both the GEM, the ECM and even the UKMet have toyed with at least a temporary disruption of the zonal flow in recent days.

 

Nevertheless, I find it encouraging to note the changes we already have in terms of how the upper flow is amplifying. Whether that will translate into the scenario I described above is highly debatable, but, like I said, not impossible.

 

I would suggest anyone interested to go and look at the buildup to the famous cold spell in November/December 2010, to see a classic example of how a real block develops - and I think that occasion IS classic.

 

Whatever happens this time around, I believe that the mere presence of a Scandinavian HP in January, with that persistent upper high accompanying it, is an excellent sign for its recurrence either later this month or early next. Meanwhile, I shall continue to watch how the models grapple with this scenario, with great interest. So much potential here- let's see what happens!

 

 

[BlueHedgehog074]

Sorry to be a nuisance, but does anyone know where I can view the full Northern Hemipshere version of the UKMO charts? It's also to look out for those aspects Nick Sussex mentioned. On Meteociel, there doesn't seem to be an option to view the whole Northern Hemisphere version of the chart (even though I've seem other people post them on here in the past), whereas with the other models, I've had no problem finding the link on Meteociel to view their full Northern Hemisphere versions (unless the link for the UKMO version is just hidden or something). Thanks.

Edited January 15, 2014 by DiagonalRedLine

[nick sussex]

Sorry to be a nuisance, but does anyone know where I can view the full Northern Hemipshere version of the UKMO charts? It's also to look out for those aspects Nick Sussex mentioned. On Meteociel, there doesn't seem to be an option to view the whole Northern Hemisphere version of the chart (even though I've seem other people post them on here in the past), whereas with the other models, I've had no problem finding the link on Meteociel to view their full Northern Hemisphere versions (unless the link for the UKMO version is just hidden or something). Thanks.

It should be there at the top under cartes n-hemi on the UKMO page.

[karlos1983]

Sorry to be a nuisance, but does anyone know where I can view the full Northern Hemipshere version of the UKMO charts? It's also to look out for those aspects Nick Sussex mentioned. On Meteociel, there doesn't seem to be an option to view the whole Northern Hemisphere version of the chart (even though I've seem other people post them on here in the past), whereas with the other models, I've had no problem finding the link on Meteociel to view their full Northern Hemisphere versions (unless the link for the UKMO version is just hidden or something). Thanks.

You can view them on Meteociel, but not 850's for all the run for NH Edited January 15, 2014 by karlos1983

[SMU]

http://www.meteociel.fr/ukmo/runs/2014011512/UW144-21.GIF?15-18

 

Evening - not much to cheer about recently-

 

perhaps the UKMO day 6 lures us into some prospects of snow- especially the further North & East you go-

A South East Wind vector & uppers of -2 / -3 c

http://www.meteociel.fr/ukmo/runs/2014011512/UW144-7.GIF?15-18

 

At a stab thicknesses @ 850 around 1300 DAM looks borderline to sea level but certainly above 200 M look good-

 

ECM 120-

http://www.meteociel.fr/modeles/ecmwf/runs/2014011512/ECM1-120.GIF?15-0

 

Not as good around 5 degrees flatter & the shallow feature over the UK is modelled further North.

 

regards

Steve