Model Output Discussion 18th Nov.2013-12z onwards.

[IDO]

This is quite interesting from the ECM:

 

50% of the GFS ensembles were going for a similar setup at the same time period (the ECM is kind of a mid way solution):

Not much support from the other models apart from the NAVGEM and BOM though.

Yes, and as others have said, as the HP cell floats about the UK, the best we can hope for is the toppler, giving us 1-2 days of temporary colder conditions.

The pressure chart highlights this (London):

The Greenland Pressure chart suggests this may be a repeating pattern at best with clearly no prolonged height rises there:

Though this morning's CFS 06z run has three weeks of zonal from early December till a few days before Christmas, when the pattern becomes more blocked again. Early days for December's signal but no sign showing of prolonged cold for the moment.

[nick sussex]

i wouldnt assume anything re temps under a block at the back end of november. could be cold and foggy or warm and sunny. or just cloudy, average and damp.

 

ecm NH plot shows the west siberian vortex fighting to send energy back towards the pole and canada beyond. this is where it begins to get interesting on a macro scale. currently, i would say the vortex will prove to be too strong. however, it wouldnt  take much to flip to those gfs fantasy NH set ups we saw on the ops and ens over the past few runs.

 

and nick, i admire you trying to make a 'silk purse out of a sows ear', but i think you'd be better watching the cricket highlights and playing a longer game than that particular shortwave. even if it behaves, it hardly makes a massive difference this side.

I agree but its a case of scraping a bit of interest whilst waiting for a more favourable NH pattern. The best possible given the overall pattern is a brief northerly toppler.  We can still manage that with an earlier phasing of those shortwaves and a bit more amplification, its of course not going to fundamentally change things over Greenland but at least it gives some interest. The GFS doesn't want to know at all and so just a smallish chance at present, we'll see tomorrow.

[forecaster]

Very mild that 8c uppers but dry thank heavens

 

With that chart I would expect a solid, thick deck of stratocumulus, coupled with relatively mild nights and maxima perhaps about 3C higher than the overnight low. Most places would still struggle to hit double figures.

[shedhead]

Still some differences between GFS and ECM in the longer term (think we are fairly confident now what's going on short/medium term), but whilst ECM continues to chop and change the degree of potential amplification towards the end of the run, GFS remains rock solid in letting Uncle Barty move into the spare room.  Frankly it's hard to get a rizla paper between the last 3 or 4 T+240hr charts from GFS, so whilst this is by no means a guarantee of how things will pan out on Dec1st, it is imo a fairly decent indication of the overall pattern.

 

Edited November 21, 2013 by shedhead

[Thundery wintry showers]

I am expecting most places to be cold and bright from this anticyclonic spell until Sunday, although there will be scattered showers down the eastern side of Britain associated with the weak northerly flow on the eastern flank of the high.

However, I am anticipating a cloudy week next week with milder temperatures, as we pick up some warm, moist air from the Azores region on the northern flank of the high:

http://cdn.nwstatic.co.uk/gfsimages/gfs.20131121/12/108/h500slp.png

Southern parts of both England and Wales may hold onto colder brighter conditions though.

[Summer Sun]

Latest from Gibby on the 12z models

 

All models show High pressure in control of the UK weather for the reliable future which is about 7 days at the moment. The High pressure will generally stay just to the West of the UK and although innitially has well broken cloud on it's UK flank will with time fill in with cloud and milder air rounding the Northern periphery of the High and down over the UK next week. As a result the chilly weekend to come with some frost and fog patches will become less chilly next week but fairly uninspiring as a lot of cloud sets in with even a little drizzly rain possible with probable low light levels at times. Night time frosts will become much less widespread as will fog but this may appear on the hilltops at times.

 

GFS shows little change as we move through the latter stages of the run, firstly pulling the High just to the South of us with a mild Westerly flow before falling pressure brings the chance of something a little more changeable and volatile by the end of the run.

 

UKMO shows High pressure anchored near Southern Ireland with a light and moist Northerly flow over the UK. It is likely to be cloudy for many but with a few holes in places allowing a little sunshine here and there and mist, fog and frost patches overnight but in general conditions will be very average temperature wise.

 

GEM looks like GFS tonight dropping High pressure down into France later next week with mild and windier Westerly winds bringing the threat of rain to the North but precious little in the South.

 

NAVGEM holds High pressure to the SW of the UK with a slight NW flow over the UK with cloud laden skies and generally benign weather conditions with temperatures showing little diurnal variation.

 

ECM shows High pressure out to the West and SW with a slack airflow over the UK biasing Northerly in direction. Some more interesting conditions do threaten the NE, East and SE periphery of the UK at times but become quickly thwarted by returning tropical maritime air rounding the High to the SW.

 

The GFS Ensembles show a mixed bunch tonight in general favouring fairly average conditions with rather more unsettled conditions likely eventually. There are a few cold options shown tonight after a universally milder interlude around a week from now.

 

The Jet Stream continues to show a Northerly aspect to it's latitude for the reliable future tonight.

 

In Summary there is little notable difference to the overall pattern tonight. High pressure remains in control to the West or SW with brief flirtations with rather more unsettled and interesting weather at times to the north and East. However, until this mid latitude block is removed (and they can notoriously stick around for a long time) then the weather will continue to be all about chasing breaks in the cloud in an otherwise benign and quiet period of weather with patchy frost and fog should those breaks develop overnight.

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

[Weathizard]

Bartlett has come to town... Oh the joys! Only just managed to take a look at the models today and I don't like what I see! Good thing is we are not even in winter yet, bad thing is that Mr Bartlett has a stinking habit of lingering around much longer than the models show.

[Methuselah]

Going by the last two posts, hibernation might be the best option...You can't see the models from deep inside a cave!

[Frosty.]

The GEFS 12z mean shows an anticyclonic spell next week but in terms of sunshine and frost, it looks like the high will pull further southwest in response to the vigorous low heading towards northern scandinavia and allowing slightly milder and cloudier atlantic air to flow over the top of the high and down across the uk but I still think we could be in for a cold snap during early december. We should probably make the most of any clear and frosty weather in the coming days because it looks like turning into a dirty high next week, wish we could just fast forward to T+192 hours on the Ecm 12z and have a blast of colder cleaner air from the north and perhaps the ecm will build on the idea of a cold blast and flesh it out into a bigger beast. I really hope we lose those heights to the south and allow a more free flowing pattern instead of high pressure continually building north and slowing things down....I want a proper cold spell in december and we shouldn't rule it out, remember how in late october how mild and boring november was expected to be and then we got the nice cold surprise, same can happen next month but on a bigger scale.

[MPG]

Could someone who actually knows what they are talking about explain what a real Bartlett is and whether the current output is showing that setup? This has been mentioned in previous winters here, and every time the person forecasting it has got it wrong. Thanks.

[Thundery wintry showers]

Many members over-use the term "Bartlett" to refer to any anticyclone that is placed in a favourable position to bring above-average temperatures to the British Isles.

 

However, a real "Bartlett" high is a strong anticyclone that settles over central parts of Europe and leaves Britain under a warm, moist west to south-westerly flow on its northern/north-western flank, and which refuses to shift for long periods.  Here's one example:

http://www.wetterzentrale.de/pics/archive/ra/1989/Rrea00119890116.gif

[Catacol]

Current SSTs:

 

 

 

Mid atlantic high still aided by this profile. A steep temperature gradient due north of the UK. Not a region that usually spawns LP, but presumably good news should we have a trough drop over us or the holy grail of a polar low form. Overall a good match for mid atlantic height rises on and off with trough dropping down over the UK. Northerly outbreaks still our best shot for the forseeable. W to NW more likely once the current high pressure sinks.

[MPG]

Many members over-use the term "Bartlett" to refer to any anticyclone that is placed in a favourable position to bring above-average temperatures to the British Isles.

 

However, a real "Bartlett" high is a strong anticyclone that settles over central parts of Europe and leaves Britain under a warm, moist west to south-westerly flow on its northern/north-western flank, and which refuses to shift for long periods.  Here's one example:

http://www.wetterzentrale.de/pics/archive/ra/1989/Rrea00119890116.gif

Thanks. Well been through the GFS anyway, cant see any Bartlett in low resolution.

[tcc]

Could someone who actually knows what they are talking about explain what a real Bartlett is and whether the current output is showing that setup? This has been mentioned in previous winters here, and every time the person forecasting it has got it wrong. Thanks.

This expression gets used way too much these days, it's explained here: http://weatherfaqs.org.uk/node/117

 

It's basically a belt of High pressure centred in the wrong place for us to get any meaningful cold, as a pulse of HP from the Azores to Europe and then that pulse dies and then another pulse takes it place and so on and so on and so on. I think it was Feb 88 where there is a classic example!

 

Hope that helps

[Methuselah]

Come on peeps...don't post one-worders?? 

[MPG]

This expression gets used way too much these days, it's explained here: http://weatherfaqs.org.uk/node/117

 

It's basically a belt of High pressure centred in the wrong place for us to get any meaningful cold, as a pulse of HP from the Azores to Europe and then that pulse dies and then another pulse takes it place and so on and so on and so on. I think it was Feb 88 where there is a classic example!

 

Hope that helps

Thank you. So could someone post a chart from the current output showing this Bartlett high some people keep talking about? Please don't post anything in FI because if cold was showing in FI that would be considered as not a chance of verifying. Thanks.

[Matty M]

ECMWF ensembles show operational was a mild outlier for both Dublin & London.  

[Cloud 10]

Come on peeps...don't post one-worders?? 

 

Bartlett  should be covered by the swear filter.

 

I suggest "cheeseburger and fries" to replace it,so an example of a post could be:

 

 

"some mild weather showing up on GFS FI this evening as a large cheeseburger and fries sets up over Europe"   

[Summer Sun]

ECM ensemble shows high pressure lasting to at least day 10

 

 

Frost and fog could develop but other than that a quite 7 to 10 days coming up giving everywhere chance to dry out

Edited November 21, 2013 by Summer Sun

[Tom Quintavalle]

I've got to say on a pretty quiet day in the model thread, with some pretty despondent posts, (dont know about anybody else but my calendar reads 21st November), its been refreshing to read posts by Nick Sussex, Tamara and a few other posters, sorry if I havnt mentioned you by name.

Members in both camps, whether it be the mild or cold ramping brigade, should learn from their example of how to construct a well balanced, reasoned post, without bias. Many members like myself, although having a reasonable amount of knowledge, look to posters like the ones mentioned above, to further their understanding of synoptic meteorology and how teleconnecting elements, impact on weather patterns. Also how important developing weather patterns upstream are to influencing the synoptic profile in our tiny part of NW Europe.

I found the MOD thread a very informative place this summer with some very interesting posts, giving well reasoned arguments as to how future synoptics were likely to pan out but unfortunately silly season is upon us again, with the resultant rollercoaster of emotions and outbreaks of tribal mud-slinging. What on earth new members must think of it, I really dont know and for those of us who want to further their knowledge of this fascinating science, its a thread at times to avoid, as some of the really interesting posts get lost against the background white noise of bickering and squabbling!

 

That could well be an off topic post mods but I think it needs to be said, for the well-being of the thread in general.

 

Tom.

Edited November 21, 2013 by Kentish CZ

[Matty M]

ECMWF notably at very top end of ENS for Dublin, Ireland.

 

 

[Newberryone]

The dreaded Bartlett High.  Pity this system can't be blown out of the water and cease to exist forever.

A tad extreme I would have thought considering it was such a high that overall gave us the great summer we had. Not that I'm pleased with today's models and the prospect of one taking up residence in a weeks time or so but surely in summer/early autumn one would have thought Uncle Bart would receive the red carpet treatment.

I'm pretty sure even Frosty would back me up on this one 

[bluearmy]

The 12z gefs looked less split in week 2 wrt the vortex so its no surprise to see the naefs flat to our west. Tbh, the spreads and the twitching of the flow indicate possible transient northerlies possible but generally in line with Exeter's update. MLB affecting the southern half of the UK the most with depressions running across to the north of scotland from time to time. The only route to cold would appear to be a slow one via developments over the polar regions. I am currently of the opinion that the vortex looks too strong and my earlier post re transferring energy between siberia and canada on our side of the pole continues to be relevant.

[East_England_Stormchaser91]

Bartlett  should be covered by the swear filter.

 

I suggest "cheeseburger and fries" to replace it,so an example of a post could be:

 

 

"some mild weather showing up on GFS FI this evening as a large cheeseburger and fries sets up over Europe"   

In the winter time, I couldn't agree more. However, in summer, I tend to love them. They should only be allowed to form in the summer, whilst Northeasterlies should be banned completely from May to September. 

Looking like it could be getting extensively foggy into next week. At least it will feel peaceful, quiet, calm and still. Just the weather having a weeks rest I guess!

[stainesbloke]

Am quite happy with high pressure taking up residence on or near the UK for a while. Fog and frost are some of my favourite Winter weather types and if the day times are sunny, then perfect. Will allow things to dry off a bit too, the ground is pretty sodden here.