Model Output Discussion: 12Z (02/12/12) And On...

[Gustywind]

The GEM isn't a patch on the ECM though Eye, it's a brief end of the line easterly where the high pressure quickly sinks towards the UK, too much energy in the northern arm. It would certainly be cold with the GEM , but not very snowy.

[snowking]

ECM has already been discussed so no need to discuss further

The GFS ensemble mean at day 10 remains decent:

Very similar, Infact, to the ECM ens mean

http://www.meteociel.fr/modeles/ecmwf/runs/2012120400/EDH1-240.GIF

Though a bigger hint if an undercut on the ECM mean it must be said

A few concerns with the GFS 0z, but ensemble means remain as per yesterday's. Unless we see a big switch from these on the 12z's (and I think crucially unless we see the ECM shift things eastwards) then there's still no need for panic

SK

Edit: height comparisons

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/test8.gif

Edited December 4, 2012 by snowking

[nick sussex]

A mixed bag of output this morning with the UKMO the least positive of the big 3.

Theres not much support for its 144hrs in the ECM ensembles, so I think its an outlier solution.

Both the ECM/GFS are decent outputs the latter just shows a different orientation of high which means that you're more likely to get a battle ground scenario near the UK, ie someone ends up with alot of snow!

The ECM has the more favourably orientated high if you're looking for that eventual sunshine and snow showers off the North Sea.

Indeed if you look at the later output the ECM has a strong cell over Scandi with some energy dropping between that and the high over Russia.

Sometimes big isn't always better! if you remember last February the high was far too big and flabby near the UK with its core well to the east , you are better off having that smaller high cell to the ne once you've got the cold uppers to the east ready to be advected west.

The real uncertainty at the moment is the drop down point of the shortwave, you preferably want this dropping into the Low Countries.

With this type of pattern it really is all to do with the curve of the jet back into the UK, so you need at least the pattern sufficiently west. And this curving ne/sw back in towards the UK.

[TEITS]

The GEM isn't a patch on the ECM though Eye, it's a brief end of the line easterly where the high pressure quickly sinks towards the UK, too much energy in the northern arm. It would certainly be cold with the GEM , but not very snowy.

For some reason the Wetter version differs to Meteociel.

http://www.wetterzentrale.de/pics/Rgem2401.gif

Very odd.

[Gibby]

Good morning. Here is the latest report of the 00z output from GFS, UKMO, GEM and ECM for this morning Tuesday December 4th 2012.

All models show a similar pattern now up to and including the weekend and Monday of next week. A rather cold NW flow covers the UK currently. Through tomorrow a trough moves South over England and winds turn Northerly dragging even colder air South behind a weakening band of rain and snow tomorrow. Thursday sees a cold day after a frosty night as a ridge becomes replaced by a strengthening Westerly wind and rain and sleet spreading down from the NW as a deepening depression is shown to move SE across Scotland and down the North Sea by Friday. The rain and snow clears the SE with a cold and strong Northerly flow for a day or so with frequent sleet and snow showers to the North and East. Frosts will then become widespread and hard overnight through the weekend as pressure rises strongly with High pressure close to Southern Britain late in the weekend and start of next week.

GFS then shows a ridge over the UK drift slowly East and become absorbed by a large Northern European High with a cold SSE wind developing over the UK in dry conditions away from the far West. Through FI this morning the trend shows winds backing slowly and surely towards the East with cold continental winds taking hold. There would be a lot of dry and cold weather around with some wintry flurries near the East coast and the threat of more substantial snow to the SW at times as milder air approaches Southern areas turning the snow to rain on this occasion later.

The GFS Ensembles are not quite as good for cold lovers this morning with a huge spread of uppers between +5C & -10C. The colder options still have the upper hand though with the prospect of at least a rather cold or cold spell to come, especially in the South. Precipitation is more prevalent for the North where the operational was a cold outlier. The South looks like seeing a fair amount of dry weather under higher pressure conditions.

The Jet Stream continues to be shown to flow East or SE over or to the SW of the UK and down towards Southern Europe. Later next week the flow ridges High over the Atlantic and disrupts almost entirely around the UK leaving a weak flow high up in the Arctic and another over Southern Europe. A new stronger arm begins to head East over the Atlantic at 50N latitude at the end of the reliable prediction range.

UKMO for midnight on Monday shows High pressure over NW Europe and a larger one over Northern Russia. Low pressure is held well out in the Atlantic making for a an anticyclonic South or SW flow over Britain giving typical early winter conditions of chilly bright weather by day with frost and fog patches night and mornings, at this point particularly in the South.

GEM this morning shows a similar pattern but with a small Low over Denmark encouraging a pressure rise to the NW which links to the Scandinavian High bringing a cold ENE flow across the UK under a ridge with the end of the run showing High pressure close to NW Scotland to Scandinavia and a slack and cold North to Northeast flow over the UK bringing cold and frosty weather with just the chance of a wintry shower near South-Eastern coasts.

ECM shows a similar pattern to the UKMO model on Monday before a stubborn Low pressure over Denmark and Germany slows the advection West of cold air West to the UK from Europe. Nevertheless, in time it does and by the end of the run high pressure has taken a stranglehold over NW Europe with a cold NE flow bringing the risk of wintry showers of sleet or snow into the SE while all others stay dry, cold and frosty under a ridge of High pressure from the NE.

In Summary it still looks like a colder spell is on the way. How much colder is yet to be decided and is entirely dependent on how the building blocks fall in favour of the British Isles or not. After this weeks taste of snow for some there looks little on offer thereafter as High pressure looks like being in control though if the East or Northeasterly materializes then some wintry interest is likely for Eastern coastal counties. It's a rocky road of model watching which is going to keep rolling until the end of this week before things become clear one way or the other.

[johnholmes]

http://www.maccinfo.com/cat/

shows snow at the Cat and Fiddle and also the village of Flash both around the 1500ft mark

[Polar Maritime]

http://www.maccinfo.com/cat/

shows snow at the Cat and Fiddle and also the village of Flash both around the 1500ft mark

Yes snow showers here to John

[AWD]

EC ensembles continue to put Europe into the freezer next week with the majority going sub zero;

http://www.weerplaza.nl/15daagseverwachting/?type=eps_pluim

Going colder, but just how cold, and whether its cold enough for model output viewers remains to be seen.

[snowking]

For some reason the Wetter version differs to Meteociel.

http://www.wetterzentrale.de/pics/Rgem2401.gif

Very odd.

Unfortunately I think it's WZ that's wrong here

This is the GEM panel from elsewhere:

http://meteocentre.com/models/cmc_geps_eur_00/PNM_panel_240.gif

I'll have 9, 10 or 20 please

SK

Edited December 4, 2012 by snowking

[snowmadchrisuk]

The GFS ensembles actually have a respectable degree of agreement for a milder start to next week now, before the usual FI scatter sets up;

http://www.wetterzen...chester_ens.png

In FI there are roughly an equal amount of cold members (below -5c) as there are milder members (above 0c).

If you look at the avg temp on the GFS Ensembles , then you will see maxes are 3-4 degs , so no mild next week in my eyes , 850's are not representative of the actual temp as a High in Winter delivers surface Cold.

[kold weather]

My only warning with regards to those ECM ensemble temps is the fact that Europe could go into the freezer but if the thing sets-up just too far east we'll end up getting no where as cold as we would if we got the full hog.

I'd be amazed if we didn't get cold, bnut the models are still trying to keep that Candian vortex going for a little longer yet, and its certainly not as weak looking as it was being modelled a couple of days ago.

[weather eater]

http://www.maccinfo.com/cat/

shows snow at the Cat and Fiddle and also the village of Flash both around the 1500ft mark

Not far from me only higher up, certainly not snowing here, supposed to be showers but it’s been raining continuously for at least the last two and a half hours. On saying that I’ve just seen some bits of snow mixed in with the rain, I suspect some of the hilltops like Chinley Churn might be a bit white on top, that’s if I could see them through the murk.

In terms of the models, not that I trust its output, but NOGAPS appears to have gone back to the evolution the GFS was touting a couple of days ago.

[SLEETY]

EC ensembles continue to put Europe into the freezer next week with the majority going sub zero;

http://www.weerplaza...?type=eps_pluim

Going colder, but just how cold, and whether its cold enough for model output viewers remains to be seen.

Not impressed yesterday we saw the -25 c line on the temp graph,today we are only seeing the -20c line so a downgrade this morning

At this rate it will only hit the -15c next run,oh well back to the drawing board

[WhiteFox]

My only warning with regards to those ECM ensemble temps is the fact that Europe could go into the freezer but if the thing sets-up just too far east we'll end up getting no where as cold as we would if we got the full hog.

I'd be amazed if we didn't get cold, bnut the models are still trying to keep that Candian vortex going for a little longer yet, and its certainly not as weak looking as it was being modelled a couple of days ago.

Indeed. The Canadian vortext is just strong enough to keep the core of the Siberian high just that bit further East. How many times have we seen this with an Easterly? Having said that, I don't put much value on charts forecasting the PV at such a range, so the high could easily shift further west (or indeed further East). As with most other battle-weary model watchers, it's a case of wait and see as teh block ebbs and flows over the next few runs. In these situations I generally regard t+72 as FI. In this case, there are still adjustments to be made for the path of the LP over Europe; there is just enough energy there to cause the secondary low to deepen slightly and rotate around Friday's low and thus stop the HP moving West; with a few adjustments it would be simpler for the HP to move more directly West.

[phil nw.]

A disappointing step back from a cold easterly on the 00z`s.They are showing again the scenario of a couple of days ago where the link up of the Atlantic and Siberian heights are at least delayed by the stubborn Upper trough just to our east.

There is time for the models to change again yet as this area is a very complex setup as the trough continues to disrupt spawning those little lows that are moving down from the Greenland/Iceland area.

Edited December 4, 2012 by phil n.warks.

[bobbydog]

i know everyone wants a classic easterly but looking through the 00z it shows a relentless attack on the block from the atlantic. what is apparent though, is that it never breaks through the block. in fact (in this FI hypothetical scenario) it gives us a potentially extended battleground situation (it actually models one lasting 4 days). given the tendency to overblow the strength of LP systems, we would more likely be on the cold side of the battleground and we could get massive amounts of snowfall from that!

may the force be with you....

[Rob K]

The ECM is consistent and that for me is the main thing to come out of this mornings runs.

Yes, consistent in that the easterly is still at 240 hours, just as it was 240 hours ago ;-)

[pyrotech]

Yesterdays ECM mean at 168 is pretty much identical to todays Det for the same period, so no big swings from ECM this morning.

To be honest you would be better comparing the same run time than two different runs, one is the 00z and one is the 12z they will always be different and sometimes hugely. compare runs from same time and you will notice either subtle differences showing the adjustment trend or a complete flopping which means either a new trend found or huge uncertainty. In all honesty checking each run against each other in fi is only going to boil your heads. Keep it simple run to run and the prozac may not be requited.

[TEITS]

The LP off the coast of Scandinavia is doing my head in.

Ideally we want this further S and tracking on a more S,ly vector rather than E. The quicker the SE and further W this drops the quicker we get our E,ly.

[SLEETY]

Odd comments in here today gfs ecm both showing easterlies in their long range output, GP confident still

Nice update from Matt hugo and yet people here think its a disappointing step back from a cold easterly on the 00z`s

[danm]

Latest from Ops Centre:

The EC solution has been favoured at the moment, with slightly more support, but with the caveat of occasional frontal incursions into at least in W’ern parts of the UK."

Good to hear that they are currently favouring the EC solution.

[BLAST FROM THE PAST]

(Mods: apols, not off-topic as this underpins all debate on this thread!):

Agreed, wasn't suggesting such. All I'm reflecting is that anyone prepared to offer reasoned, scientifically-based and crucially, openly explicit hypothesis on either near-term forecast (as UKMO staff do daily) or longer-range (as GP does) deserve credit. Anyone who has ever submitted a scientific paper for publication in any discipline can attest to the stress when it enters peer review, but this key process is what delineates between true scientific endeavour versus the charlatans and poseurs. For this very reason, I truly despair when I see ill-informed, vitriolic anti-UKMO rhetoric on forums levelled against people who work hard to advance meteorology in the face of day-by-day public and media scrutiny and critique. Arguably, no other scientific discipline faces such barrage with such daily regularity.

Back to the models (thanks, Mods!)

Ian

Its the quotes from David Viner of CRU et al of snow will be thing of the past, the BBQ summer etc etc that fuel it. He isn't UKMO but it doesn't matter as people and organisations are misquoted and folk think all are linked to UKMO one way or another...and indeed the MetO are pro AGW? This will never change and the reason being back for example in the 90s I was visiting my Mrs in the Elephant and Castle [early days} and her neighbour said its going to snow tonight, the weathermen said. I had seen the forecast and the snow was forecast for Scotland. She just heard snow and assumed it was for UK as a whole. It showed her 'ignorance' and can be seen in any folk with a lack of knowledge of a subject and something probably done my most of us somewhere along the line. Anyway I digress.

I watched the SE forecast today and today we have 6c then 3c then 4c and 4c. Come Saturday we have 20mph winds and 4c temps....that will feel perishing!! What is interesting me and touiches on what Ihave spoke of yesterday is that we have a ridge coming over us at around t144 from the SW yet the temps remain on lower side particularly for east, then cold comes back in. Whether we get sustained cold yet i don't know but the scenario of it being around/holding for the east and close by with Far SW and W getting less cold interludes is IMO now at least on the table....will we get the block back further west and get full cold thrust?

ECM T120, t144, t168.....look how as the less cold tries to encroach from the W / SW as the ridge moves in and a LP to the north, the door gets shut on it from the NE as the block re-affirms control.

This then leads to this on this run.

The cold backs west again affecting all UK and Ireland with it not really leaving the eastern half of the UK. The GFS does a similar sort of thing but we get a SE'ly flow with the milder Atlantic air still affecting the SW/W. This is worth watching, will we get the full blast or will we see a continued battle going on.

BFTP

Edited December 4, 2012 by BLAST FROM THE PAST

[nick sussex]

The shortwave is now taking a sightseeing tour to the ne.

Not the right cut back in the jet towards the UK, if its not going to head se further west then rather than just sit to the ne its better for it to just head away to the ne, this might allow the ridge to the ne to head in but a bit further south.

Here we are again discussing a Norwegian shortwave, some things never change!

[Weathizard]

Perhaps its my untrained eye but I think the GFS at 144 looks rather better, lower heights over Europe, Atlantic low looking to undercut.

[shuggee]

In my mind, the latest outputs, and people's reactions are understandable, but there's been one missing element. We've had great synoptics already this season and in late autumn, but not deep cold making it to the UK. Those charts have always stayed out at T+168 and beyond - Fantasy Island, a name that does what it says on the tin. However, things are about to change that might (an important caveat) bring the missing element to support blocking oooop north - a warmer than average stratosphere. We had this in mid November 2010 and it delivered big time. We've got the synpotic potential but just need that last domino to fall and so far the effect of a record cold stratosphere has perhaps prevented what many members want to see. That willl change in 14-21 days time, and in about 7 days time expect the models to start picking up its effect. And that's Christmas!

Stratosphere thread here http://forum.netweat...watch-20122013/