Model Output Discussion 17th Dec.2013-12z onwards.

[Cloud 10]

The ECM 144hrs looks like a major snow event for Southern Scotland if it came off.

 

 

 

Quite a test for the ECM with it being quite different from the other models.

[legritter]

Nice to see the vortex being attacked at last ,its early days yet with many days of ups and downs expected in the Models unless we get a smooth ride which i dont think in this weather game .Absolute loads of weather coming up over the coming week or so ,so it should be very interesting going forward .still some uncertainties regards Christmas day and boxing day as troughs at 4/5 day range are hard to predict so some possibilitys as regards the white stuff somewhere and considering where we were 10 days ago it sort of gives you an idea how hard it is trying to predict Jan 1st at this range .catch up later after tonights runs wonder what s out on that horizon which is so UNpredictable ,Cheers all  i,ll have a Half .

[Duane S.]

I have never spent a more intense few days watching every single model chart output as the past few days. Not because I think there is something incredible on the horizon, moreover I have vested interest as am off to the French Alps in 2 weeks, so I have been scrutinising (for trends only obviously) the NH profile, the jet in particular and potential upstream factors.

 

So with my glass firmly half full, there have been subtle hints way before today's 12z and now it is beginning to show its hand. Are we looking at an influential MLB (HLB very early Jan a big ask) block building to our East? If this trend continues it could be a double whammy for me with first of all cold uppers and PPN hitting the slopes with the potential then for retrogression further NE, for me to then arrive back to the UK just as winds veer Easterly for us in the UK?

 

I'm not saying it is going to happen but I have seen enough to believe it is a very viable prospect.

Edited December 21, 2013 by s4lancia

[Summer Sun]

Well once again we have big differences at t144 from the big 3

 

UKMO and GFS both going for another big LP system to hit the UK

 

 

Whilst ECM is going for a 960mb low centred around central Scotland

 

 

Which pulls away quite quickly

 

The ECM 144hrs looks like a major snow event for Southern Scotland if it came off.

 

ECM1-144.gif

 

 

Quite a test for the ECM with it being quite different from the other models.

 

Would it be cold enough at t144 for a snow event in Southern Scotland?

 

[bradymk]

Where are you going?

Edited December 21, 2013 by bradythemole

[Cloud 10]

 

Would it be cold enough at t144 for a snow event in Southern Scotland?

 

 

 

850  temps. only around -3/-4 but with very low thicknesses and heavy precipitation snow 

would be likely even at modest elevations.

[TSNWK]

Where are you going?

Yep I was wondering too.. Not sure what happens at 240, seems to disappear.

[Captain Shortwave]

Well it's looking a little better.

weak surface heights over Greenland squeezing the Polar vortex a little and allowing it to retreat westwards, nothing very cold here yet but would have better chances here, as well as the GEM output.

[The PIT]

Gavin, is that all you can say about that day 10 gem ? 'Another low waiting in the wings'

Well use fifty paragraphs when one short sentence says it all. Only in deep FI is there any slight hint of possible change to this stormy period. Now how deep will that low go? 930 or much less?

[bluearmy]

And just a bit more condescending BA. This is exactly why people refrain from posting. Fear of a reprimand.

 

i was drawing attention to the fact that this is a 'monster' chart for coldies, yet gavin (who lets face it, is not a novice on here) had only seen 'another low'. (or decided to see it like that). if i wasnt making dinner at the time then i could have made a more in depth comment. i merely wanted to put gavin's post into context.

 

the 12z suites, thus far, are the most promising for wintryness in ages.  a general rise in heights this side of the pole as we head through week 2 and a sudden appetite for the jet to head south again at a timeframe when most of the extended ens suites had it drifting back north.  the 12z gefs are quite amazing, when put into the context of what we're expecting to see on the polar profile. the trop vortex well and truly split and finally signs that some HLB might not be as far away as some might think. it is one run from ncep but then the ecm and gem are both heading the same way.  oh sorry, i almost forgot - we're only in the early days of weeks and weeks of mild mush zonality.

 

and mucka, keep the faith but the extended ens really were't showing much to hang your hat on. maybe the full picture of the 12z's later will change that .

[cooling climate]

i was drawing attention to the fact that this is a 'monster' chart for coldies, yet gavin (who lets face it, is not a novice on here) had only seen 'another low'. (or decided to see it like that). if i wasnt making dinner at the time then i could have made a more in depth comment. i merely wanted to put gavin's post into context.

 

the 12z suites, thus far, are the most promising for wintryness in ages.  a general rise in heights this side of the pole as we head through week 2 and a sudden appetite for the jet to head south again at a timeframe when most of the extended ens suites had it drifting back north.  the 12z gefs are quite amazing, when put into the context of what we're expecting to see on the polar profile. the trop vortex well and truly split and finally signs that some HLB might not be as far away as some might think. it is one run from ncep but then the ecm and gem are both heading the same way.  oh sorry, i almost forgot - we're only in the early days of weeks and weeks of mild mush zonality.

 

and mucka, keep the faith but the extended ens really were't showing much to hang your hat on. maybe the full picture of the 12z's later will change that .

There are indeed some promising signals starting to show up in the NWP charts as

in the strat charts and with the strongest part of the vortex anchored over the Canadian

side it is no coincedence to see pressure rising to the north east.

Or you could look at it that its because pressure is rising to the northeast the strongest part

of the vortex is over Canada.

Edited December 21, 2013 by cooling climate

[SMU]

Evening All-

 

Probably the best ECM run for some considerable time tonight- OK, say the real meat on the bones is @ day 9 + 10- However its been threatening for a while-

 

http://www.meteociel.fr/modeles/ecmwf/runs/2013122112/ECH1-240.GIF?21-0

 

KEY NH profile is

 

* Increased heights over the pole - nothing major but certainly a signal those can develop into something more significant, it also shows a split flow across the pole.

* See that developing patch of higher heights just east of Greenland- A signal that we should watch with interest over the next 3-4 days to see if that develops as well..

 

 

 

 

Nothing major showing thus far- however we are now starting to walk before perhaps a canter- after which Maybe a run!S

[CongletonHeat]

i was drawing attention to the fact that this is a 'monster' chart for coldies, yet gavin (who lets face it, is not a novice on here) had only seen 'another low'. (or decided to see it like that). if i wasnt making dinner at the time then i could have made a more in depth comment. i merely wanted to put gavin's post into context.

There have been "monster charts" for mildies yet many posters only see the cold possibilities in them, do you have a go at all of them?, if they only look for one thing why should he be any different?

[bobbydog]

 

 

strong PV over greenland (with a split) , strong pacific ridge. some vague similarities?.......

 

maybe.... but a big chunk of PV over greenland does not mean we are stuck with zonal.

 

anyway. keep your heads down. there's a few of these blokes lurking in the thread tonight....

 

[Troubleatmill]

Gem day 10 polar profile not without interest as well.As I said on the in depth earlier, ridging well to our ne could well be the realistic route to deep cold, given the arctic high and strong Atlantic jet.

Yes BA, no real sign of the PV weakening in the Canadian quarter, so north east 'murmansk'area looks like the quarter where the change will come from for our northern or eastern blocking to happen, long way off but signs are there, its a trap we make to keep looking west for a magic greenie high to come from WAA in the atlantic, or a european or azorzes high to drift to scandi, both are the quick routes to cold but aint going happen. Like you say models are agreeing for the slow route, but it is a route Edited December 21, 2013 by Arron B

[snow mad]

There have been "monster charts" for mildies yet many posters only see the cold possibilities in them, do you have a go at all of them?, if they only look for one thing why should he be any different?

I don't think BA was having a go! he was merely pointing out that it wasn't "just another low waiting in the wings" ... which is a good thing so people know what to look out for if colder weather is your thing

[Gibby]

Good evening. Here is the report on the 12 noon outputs from the NWP for today Saturday December 21st 2013.

 

All models continue to show a very volatile spell of weather on the road to Christmas with a very showery day tomorrow especially in the West followed by a thoroughly awful day on Monday as a vicious area of Low pressure winds up close to NW Britain with severe gales and storm force gusts affecting some areas through the day along with heavy and locally torrential spells of rain. Following this there will be heavy and squally showers rushing through on the wind with hail, thunder, sleet and snow all possible on Christmas Eve. Through Christmas Day and Boxing Day lighter winds look likely with showers more scattered as a result and confined to coastal areas adjacent to the breeze with some areas ending up dry and bright if rather cold.

 

GFS then exits Christmas with another active storm system sending strong winds and gales across the UK which only relaxes slowly as we move towards the end of the year. By New Years Eve another Low is formed close to Western Britain with more wind and rain for many areas which quickly clears NE in time for New Years day which looks much better and quieter across most areas. Changes then towards the end of the run revolve around rising pressure from the Southeast sending and weakening rain bearing systems towards Northern and Western areas while England and Wales become much quieter and drier if somewhat colder.

 

UKMO tonight shows post Christmas opening with another very powerful storm system to the North of the UK with strong to gale force WSW winds and heavy rain having cleared East to be replaced by showers with once more some wintry showers on hills and in the North.

 

GEM tonight shows unsettled and innitially stormy conditions soon after Christmas with storm force winds, heavy rain then squally and wintry showers with hail and thunder all thrown in at times. Winds do die sown towards the end of the year but the weather looks likely to remain cold and unsettled as we hit the New Year period with another Low pressure down to the SW and with pressure over Europe less in a hurry to rise.

 

NAVGEM shows very stormy weather a week from now with gale SW or West winds showers and longer spells of rain and showers, wintry on hills.

 

ECM tonight shows unsettled and sometimes stormy weather continuing right up to the New Year with nowhere immune from some very unpleasant conditions at times. Heavy rain will be all too frequent with some colder brighter weather with showers, wintry on hills in between the rain bands in temperatures close to or a little above average at times in the South later.

 

The GFS Ensembles show another disappointing set with average uppers throughout and spells of heavy rain all too frequent with sunshine and showers in between with wintry showers over the hills.

 

The Jet Stream shows the flow slipping South of the UK as we approach and over Christmas itself before it moves back North over and occasionally just to the NW of the British Isles towards the end of the run.

 

In Summary there is still an awful lot of newsworthy weather to get through before any of the models show anything of significant improvement over the coming period and even then there is still plenty of scope for further wind and rain to take us into the New Year. Temperatures in themselves will be close to average overall though this will be sufficiently cold enough for some snow over hills at times. The wind will also be a major feature with another worrying storm likely just after Christmas before things do look like moderating somewhat in terms of wind strength while rainfall build up could continue to be a problem throughout the period. Unfortunately for those looking for something rather traditionally colder and wintry will have to continue to wait as there still remains little signs of any major change to the overall pattern anytime soon while the Jet stream profile remains as it is.

[Biggin]

Back from a couple of days off from model watching and hoping (rather against hope in all honesty) to see at least some changes being signalled in the overall pattern, but alas it's just not to be.  That said the lack of 'wintry' interest is still balanced to some degree by what looks like being a very lively spell of pre Xmas weather...and that's putting it mildly!  OK not a beast from the east, but most certainly a beast from the west, with a potential centre of sub 930mb!!

 

What we're probably (and I sure some are saying hopefully) seeing here is an example of GFS's persensity to over deepen many LP's, but even so this has all the hallmarks of a significantly disruptive feature at any time of the year, let alone on Xmas Eve!!

 

You love boring.

[The Northern Ramper]

i was drawing attention to the fact that this is a 'monster' chart for coldies, yet gavin (who lets face it, is not a novice on here) had only seen 'another low'. (or decided to see it like that). if i wasnt making dinner at the time then i could have made a more in depth comment. i merely wanted to put gavin's post into context .

Gavin isn't a new poster but when it comes to reading charts he is very much the novice.

[bluearmy]

There have been "monster charts" for mildies yet many posters only see the cold possibilities in them, do you have a go at all of them?, if they only look for one thing why should he be any different?

 

yep, i have pointed out stuff like that in the past. cherry picking is ok, as long as you make it clear in your post that you are doing so.  i'd post that some need to 'chill' a bit but i'm afraid it might be viewed as a forecast !

 

can we move on now - i'm bored with this.

Edited December 21, 2013 by bluearmy

[legritter]

 

 

strong PV over greenland (with a split) , strong pacific ridge. some vague similarities?.......

 

maybe.... but a big chunk of PV over greenland does not mean we are stuck with zonal.

 

anyway. keep your heads down. there's a few of these blokes lurking in the thread tonight....

 

you never know who.s lurking in the shadows ,like you dont know synoptic situation two weeks from now ,and it could be creeping up on us in disguise .brilliant photo ,

[Captain Shortwave]

 

 

strong PV over greenland (with a split) , strong pacific ridge. some vague similarities?.......

 

maybe.... but a big chunk of PV over greenland does not mean we are stuck with zonal.

 

anyway. keep your heads down. there's a few of these blokes lurking in the thread tonight....

 

I don't think using a T384 chart to compare to one of the coldest winters of the 20th century is really going to cut the mustard to be honest. I wonder how many winters also had similar charts and turned out to be a Bartlett-fest or anything in-between.

Also worth noting that an Arctic high does not equal cold and snow for everyone either which I said earlier (only to be accused of line 3)

Yes the outlook does look better, but it's at such a distance that thing could change, yet again more irony is those slating people for saying that mild zonal weather would last a long time whilst repeating the very same mistake.

Forecast wise, lets stick with a trough close to the UK for the foreseeable and a potential easing of the Atlantic jet past Boxing day, it might open up other opportunities but it might be milder or colder solutions. Events over the other parts of the Northern hemisphere are crucial to how things will pan out here. We really need a hit on the Greenland/Canadian sector to really give a block some chance to form (where-ever that may be)

I guess I have just shot and killed someone on my team (team cold), and will be booted from the server 

Edited December 21, 2013 by Captain shortwave

[bluearmy]

but captain - the 'mild' zonal ISNT lasting for weeks and weeks. is anyone really forecasting what WILL happen for january in the same way that the 'zonalistas' did  ????  some are seeing promise in charts that dont really show it. some are seeing promise in charts that do. most are , as the season demands, looking for cold. ian is manfully being objective.  and paul will probably move this into the banter thread........................

[DAVID SNOW]

I don't think BA was having a go! he was merely pointing out that it wasn't "just another low waiting in the wings" ... which is a good thing so people know what to look out for if colder weather is your thing

 

A bit of semantics going on here, I don't think Gavin has to extrapolate on the direction of the low waiting in the wings(although the chart would suggest said low would run south east)

[Gibby]

No real light at the end of a very long tunnel from the ECM 240 mean tonight imo.

 

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

Edited December 21, 2013 by Gibby