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

[Methuselah]

12Z ECM DET a pretty close representation of previous UKMO thoughts on broadscale evolution into trend period. Suspect they'll favour it over NCEP, all things considered (ie MOGREPS & JMA) but will see in briefing later this evening. Either way, fairly standard late Autumn/early winter fare, with an oh-so 'surprising' lack of support (at least into reliable timeframe) for the recent bouts of Express/Maddenology hyperbole about a snowmageddon November hell (etc.).

You obviously read the wrong paper, fergieweather. http://www.thedailymash.co.uk/news/environment/britain-to-be-hit-by-entirely-typical-weather-201110174431 

[ANYWEATHER]

Its early days yet and  NO model has got an answer! Im thinking we are going to need a few days to see where we are going! Cold and dry looks the favourite in short term well later this week, but from past experience the devil will certainly be in the detail!!! I wont buy any synoptic output past T+96hrs at the moment as regards detail, but some interesting viewing,,,,, I just wonder what the menu is for tomorrow

[nick sussex]

I should add re the upstream pattern if you follow the ECM you can see how one low runs into the other near Greenland, this phases, when you get one low running into another further north you get the top one pulling north so it loses  its easterly momentum, if you look at the ECM as this happens some energy by way of a shortwave is being forced se as you can see by the chart I posted earlier.

 

So you get phasing, the top low pulling north and some energy heading se these happen collectively which at 192hrs sees that shortwave under the block in Spain, there are no middle ground solutions here, where the energy goes will determine the location of the high re how far north this is. If the energy runs over the top the high will be forced into a more Euro high position rather than one that can bring in a colder easterly flow.

Edited November 18, 2013 by nick sussex

[Mair Snaw]

You obviously read the wrong paper, fergieweather. http://www.thedailymash.co.uk/news/environment/britain-to-be-hit-by-entirely-typical-weather-201110174431 

Brilliant....always good to have a little light hearted humor when the models are giving us hell..

[Snowman.]

If I was to bank any run I would bank the 12z.

 

Shows more of a short term pain long term gain solution.

 

This is all a bit of harmless fun.

[SMU]

Evening all-

Here would be my update today based on the 12,s

The ECM continues to be at the extreme end of amplification at 96 -144 hours.

However the model has lost the signal for ridging into Greenland and the subsequent greenland high-

However because of its continued amplification sees the high maintain its northerly locale and actually is a very very good run, however not as good as the others.

The rest continue to push the atlantic energy over the top. The ECM has the most negative tilted trough tonight at 96

All models have moved to the ECM neg tilted trough solution over the last 48 hours and the chunk of vorext moving through scandi- lets not forget that but the ECM has backed away from the extreme amplified scenario- so as it stands halfway house which was the UKMO solution

S

[bluearmy]

I should add re the upstream pattern if you follow the ECM you can see how one low runs into the other near Greenland, this phases, when you get one low running into another further north you get the top one pulling north so it loses its easterly momentum, if you look at the ECM as this happens some energy by way of a shortwave is being forced se as you can see by the chart I posted earlier.So you get phasing, the top low pulling north and some energy heading se these happen collectively which at 192hrs sees that shortwave under the block in Spain, there are no middle ground solutions here, where the energy goes will determine the location of the high re how far north this is. If the energy runs over the top the high will be forced into a more Euro high position rather than one that can bring in a colder easterly flow.

The double whammy being no undercut of energy means the Euro trough will gradually fill. I think it will undercut nick. Edited November 18, 2013 by bluearmy

[karlos1983]

I should add re the upstream pattern if you follow the ECM you can see how one low runs into the other near Greenland, this phases, when you get one low running into another further north you get the top one pulling north so it loses its easterly momentum, if you look at the ECM as this happens some energy by way of a shortwave is being forced se as you can see by the chart I posted earlier.So you get phasing, the top low pulling north and some energy heading se these happen collectively which at 192hrs sees that shortwave under the block in Spain, there are no middle ground solutions here, where the energy goes will determine the location of the high re how far north this is. If the energy runs over the top the high will be forced into a more Euro high position rather than one that can bring in a colder easterly flow.

Oh the return of pesky short waves ruining our chances. Great models, but a very sobering and true analysis to keep our feet firmly on the ground. I'm glad you've picked this up early Nick, as a relatively new model watcher and keen learner, it's really important to concentrate in the detail and getting the knowledge of what to look for, be it for a good or bad outcome, from a coldie perspective. Cheers Nick, Karl

[Snowman.]

Something to consider.

 

http://www.meteociel.fr/modeles/gefs_cartes.php?code=3&ech=6&carte=1&mode=0

 

Trough disruption out west sends some north and some south.

 

Seems like a possibility.

[BLAST FROM THE PAST]

12Z ECM DET a pretty close representation of previous UKMO thoughts on broadscale evolution into trend period. Suspect they'll favour it over NCEP, all things considered (ie MOGREPS & JMA) but will see in briefing later this evening. Either way, fairly standard late Autumn/early winter fare, with an oh-so 'surprising' lack of support (at least into reliable timeframe) for the recent bouts of Express/Maddenology hyperbole about a snowmageddon November hell (etc.).

And longterm too anyone could suggest with confidence.

 

ECM remains on pretty cold side throughout, yes a lessening and a slight shift away from its great 0z chart as suspected by me and many, but its cold and not bad at all.  I think we are close to seeing what's ahead 

 

BFTP

Edited November 18, 2013 by BLAST FROM THE PAST

[CRACKPOT]

With the low pressure over the pole the ECM is less favorable for prolonged cold?

Lots of fascinating charts around and a great start to Winter - oh I forgot, we are not in Winter yet!

[Summer Sun]

Latest from Gibby on the 12z models

 

A showery NW flow will cover the UK tonight and tomorrow followed by a deepening Low pressure moving South down the North Sea on Wednesday with a spell of rain and strong winds with snow on the highest ground briefly. Following in behind will be a return to colder and brighter weather with wintry showers dying out by the weekend as High pressure builds across the UK with frost and patchy fog overnight.

 

GFS shows High pressure dominant over the UK or just to the West for most of the rest of the run with fine and dry weather with relatively light winds. After a cold start temperatures would gradually rise as warmer uppers come into the mix. However, this is dependent on the amount of fog is around and how quick it clears each day. Late in the run a brief and cold surge affects the East before High pressure returns back over the UK.

 

UKMO starts next week with High pressure anchored over the UK with fine and dry conditions but cold. Frost and fog will be the main problems in the weather over the period and daytime rather cold levels will be amplified by any persistent fog patches which fail to clear by day.

 

GEM too tonight shows High pressure well anchored over the UK through the weekend and through much of next week with cold and clear conditions though fog and frost problems will become widespread transport issues through the period.

 

NAVGEM tonight holds High pressure slightly further North over Scotland with something of an Easterly flow maintained over the South of England and Wales. Northern and Central areas will be dry and fine with frost and fog while Southern areas too are likely to see frost with abit more breeze fog may be more patchy.

 

ECM shows High pressure too across many parts of the UK at the weekend with the trend to drift it towards Scandinavia as we move through next week. This maintains cold weather across the UK with a stronger Easterly flow over the South making it feel very raw. Frosts will remain widespread but any fog is more likely across Northern areas where winds remain lighter.

 

The GFS Ensembles show uppers quite low to begin with before a slow recovery to average levels from the end of this week. However, with High pressure generally in control from many members surface conditions may be a good deal colder with frost and fog at surface level quite widespread at times.

 

The Jet Stream shows the flow moving South across the UK for much of this week before it sets up a clockwise circulation around the UK which would indicate High pressure close to the UK into next week.

 

In Summary the weather looks like becoming quite settled under High pressure as this weeks rather cold and changeable conditions give way to fine but still cold weather with frost and fog the main features to contend with. Some wintriness may accompany the changeable theme through this week, mostly over the hills. ECM and to a lesser degree NAVGEM shows High pressure held a little further North allowing an Easterly flow across the South next week but other than the risk of the odd wintry shower near the SE coast should ECM verify it looks like a prolonged dry spell ahead for many across the UK.

 

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

[Frosty.]

I'm pleasantly surprised by tonight's Ecm 12z op run, it has kept the overall structure from the 00z intact and we are flirting with deeper cold just to the east which makes some inroads, it's becoming cold now and with potential for it to become even colder during the weekend and next week, the cold block to the east/ne is tantalizingly close. Cold with widespread frosts and an ongoing risk of wintry showers is actually pretty good for late autumn...let's hope we get some snow..

[nick sussex]

Oh the return of pesky short waves ruining our chances. Great models, but a very sobering and true analysis to keep our feet firmly on the ground. I'm glad you've picked this up early Nick, as a relatively new model watcher and keen learner, it's really important to concentrate in the detail and getting the knowledge of what to look for, be it for a good or bad outcome, from a coldie perspective.Cheers Nick,Karl

As everyone knows I'm obsessed with shortwaves! Generally these pass without much interest outside of the winter months but essentially they often turn into a trigger for cold in the winter, of course they're just reacting to the overall pattern but you'll often see us mention trigger shortwaves, so in this case a cold trigger. We often see these with  Scandi high evolutions, or those SW's that head south and then everyone is glued to their track to see whether they fall on the favoured snowy eastern flank ! And of course theres the Holy Grail for many snow lovers especially further south the SW that develops into a Channel Low.

 

As a rule Karl I normally follow a what can go wrong model view for cold, my confidence in cold is really how complex the route is, how many things needs to go right, from experience and for those members that have been here for a very long time! A shortwave in this type of set up shown by the ECM is nerve shredding!

[legritter]

Yes looking towards the start of next week it would only need a slight shift in current predicted charts for something more meaty to turn up .im very happy with tonights charts as i feel from a coldies view we could be knocking on the door of something more wintry .it will always be frustrating stuff getting to an ideal synoptic situation especially in this day and age with all our technology ,Will it ,Wont it ,will it Backtrack or upgrade ,which modell is performing well ,did someone feed the wrong data in ,Pacific ridge ,solar flares etc etc .all good practice for when winter proper arrives soon .ps sorry off topic but why is there no list of posters at bottom of page or is it because of my new windows 8 ,cheers 

[Purga]

So there's me going to Scotland next week hoping for snow when the best of the cold is likely to be down South - where I live!

 

 

You couldn't make it up!

[NorthernRab]

So there's me going to Scotland next week hoping for snow when the best of the cold is likely to be down South - where I live!

 

 

 

You couldn't make it up!

 

I wouldn't go on upper air alone when determining cold - under high pressure it would be really quite cold under high pressure with the risk of ice days for many parts of Scotland. That chart is 240 hours away either way so the conditions will likely be quite different!

[Matty M]

Longer range ECMWF ensemble mean looking a bit grim at this stage with high falling south and a return to more westerly flow.

 

But im sure it is just the mean of a wide spread of potential outcomes.

[Cloud 10]

Good support for the operational 12z ECM from the ensembles,with a decent cluster

of colder runs as well.

 

[SMU]

Yes a noticeable step on from the 168 mark on the ensembles...

 

The mad season has started early this winter!

 

S

[Summer Sun]

Once the high builds later this week the ECM ensemble so it not leaving in any hurry

 

 

Given the time of year freezing fog could be a hazard at times lasting potentially all day in prone areas, frosts would also become widespread providing the high isn't a cloudy one

[zubzero]

Longer range ECMWF ensemble mean looking a bit grim at this stage with high falling south and a return to more westerly flow.

 

But im sure it is just the mean of a wide spread of potential outcomes.

Westerly flow? I'm sure I am looking at different charts to what most are half the time.

 

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

[nick sussex]

Longer range ECMWF ensemble mean looking a bit grim at this stage with high falling south and a return to more westerly flow.

 

But im sure it is just the mean of a wide spread of potential outcomes.

I think that's likely to be diluted somewhat because of the big differences regarding that shortwave, I'm actually surprised it looks as good as it does and it still keeps low heights near Iberia at 240hrs. The ensemble mean does eject that shortwave so overall not too bad.

[bluearmy]

the 850 spreads on ecm offer plenty of options re colder uppers coming in from the east towards the end of the run. the clustering shows depressions running west to east across the top of the block. that has to keep refreshing low uppers around the back of the ridge. i guess it depends how long the block can hang around. eventually, the upstream and polar pattern either retrogresses it or sinks it.

 

and nick, the spread of heights seems keen to drop that jet into iberia late in the run.

Edited November 18, 2013 by bluearmy

[Matty M]

Westerly flow? I'm sure I am looking at different charts to what most are half the time.

 

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

If you look at the movement from 192hr to 240hrs, you can see the high collapsing south and the more zonal flow returning in the Atlantic. It is just a mean of a wide spread of charts so is not to be dwelled on.