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Model Output Discussion 1200 hrs 15/11/14


phil nw.

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Posted
  • Location: Horsham, West sussex, 52m asl
  • Location: Horsham, West sussex, 52m asl

They aren't actually trop. temp charts but potential temp charts..They don't use the WMO definition of the Tropopause but Isentropic

surfaces making the transition from the troposphere to stratosphere. You can locate various features, such as blocking, by looking at the evolution of potential temperature on the dynamic tropopause. So it should be run in sequence but I couldn't do that so posted two charts instead to indicate the direction of movement from Russia to Greenland..

 

That's my theory anyway

I'd have to look at those in conjunction with corresponding strat and trop charts to get my head around them. I suppose they would show temperatures transitioning up as well as down though?

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Posted
  • Location: Epsom, Surrey, 100 Meters above sea level
  • Weather Preferences: Anything Extreme
  • Location: Epsom, Surrey, 100 Meters above sea level

Although the recent model runs have produced some tantalising possibilities of a northerly blast in the coming days, there has been no consistent trend in that direction. However, the current setup has some intriguing potential which is worth mentioning. Before I do though, I must say that this last week the models over overestimated the eastward progression of Atlantic systems, with the European HP holding its ground quite well.

The upper vortex to our south will, while it lasts, inevitably lead to some form of upper ridge to the W, and the models take this and predict some transient HP for much of the coming week, which is fair enough. However, 2 things: there is currently a significant influx of very cold air heading in N Russia which would, I think, favour strengthening HP NE of Scandinavia. The models appear to brush this feature aside.

Second, over several runs, the GFS has been developing what appears to be some sort of sub-tropical low towards next weekend moving N from N of the Caribbean, which if it were true, would be most unusual this time of year. But crucially, if it happened, a lot of very warm air would be pushed NW towards the US/Canada east coast and there would be, I think, a distinct possibility of a major upper vortex developing which would amplify the flow. As a result downstream, this could allow significant troughing into our area from the NW, perhaps feeding into what's left of the upper low to the S, which would pull in significantly colder air from the N.

Fanciful speculation? Maybe, but as I mentioned on Friday, such troughing as I discuss has certainly come about in the past on a number of occasions. It just needs some decent upstream amplification to occur.

The model output beyond the end of this week looks sillier than usual so I am inclined to ignore it completely. As I see it, even right now, there are still significant features in the upper and surface flow to suggest a much colder trend later in December. Where that cold comes from remains to be seen. I am keeping a close eye on 500mb developments in the coming days for a clearer idea of what's to come.

Great post, written with the maturity and knowledge I could only dream of having !!

 

To my untrained and very much bedroom enthusiast eye,  Looking further ahead (which always going to be about looking for trends ??), IMO that there really doesn't seem to be one and when there's a lack of trend in the models it tells me that a half way house between what is being shown is the most likely outcome. 

 

To that end I wouldn't be surprised if after this week, we see a continuation of the UK being stuck between High pressure to the West, and High pressure to the East with Low pressure squeezing between the gaps. 

 

Something a bit like what peturbation 12 is showing

gens-12-1-288.png?6

 

 

As you say though anything is plausible I just wanted to find some way of saying that your post was awesome other than putting some one liner that would be deleted :-)

Edited by EML Network
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Posted
  • Location: Camborne
  • Location: Camborne

I'd have to look at those in conjunction with corresponding strat and trop charts to get my head around them. I suppose they would show temperatures transitioning up as well as down though?

 

Well yes and cold and warm pools and CAA and WAA.

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Posted
  • Location: Surrey and SW France.
  • Location: Surrey and SW France.

They aren't actually trop. temp charts but potential temp charts..They don't use the WMO definition of the Tropopause but Isentropic

surfaces making the transition from the troposphere to stratosphere. You can locate various features, such as blocking, by looking at the evolution of potential temperature on the dynamic tropopause. So it should be run in sequence so you actually can see the evolution of the air masses and features but I couldn't do that so posted two charts instead to indicate the direction of movement from Russia to Greenland..

 

That's my theory anyway

 

EDIT: an example here/

http://www.knmi.nl/~vries/Research/research_wavebreaking.html

 

I think your charts are from a pay website so cannot be linked as the animation - FIM is free to view and here's the same parameter in animation format.

 

http://fim.noaa.gov/FIM/jsloopLocalDiskDateDomainZip.cgi?dsKeys=fim_jet:&runTime=2014113000&plotName=ptemp_pv2&fcstInc=360&numFcsts=57&model=fim&ptitle=Experimental%20FIM%20Model%20Fields&maxFcstLen=336&fcstStrLen=-1&resizePlot=1&domain=201

 

Full menu.   http://fim.noaa.gov/FIM/Welcome.cgi?dsKey=fim_jet&domain=201&run_time=30+Nov+2014+-+00Z

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Posted
  • Location: Horsham, West sussex, 52m asl
  • Location: Horsham, West sussex, 52m asl

Well yes and cold and warm pools and CAA and WAA.

I assume those charts are pay-per-view though

Edit- nice one nouska ^^

Edited by bobbydog
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Posted
  • Location: Camborne
  • Location: Camborne

 

Correct Nouska but that animation is not quite as clear cut as the T1534 regarding the vortex.

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Posted
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.
  • Weather Preferences: Winter synoptics.Hot summers.
  • Location: Kirkburton, Huddersfield - 162.5mtrs asl.

I hate to pour cold water on some of the hopes in here. Really apart from the cold 'feel' to this week for most compared to what most areas have had over the last weeks there is currently little sign of any marked change.

The upper pattern shows, see below for the general idea,

http://www.cpc.noaa.gov/products/predictions/814day/500mb.php

that is a flow from about WSW at 500mb for much of the period, and this is a consistent signal with NOAA over the past few days. This does allow for a 48h colder spell if everything falls right at the right time as cold air flows down the western side of a travelling surface feature. Once this has passed then the upper flow is going to revert to a similar pattern as indicated above.

There is no signal even further out really for any marked cold plunge. If/when this does occur I would suggest it will be from N of west not east of north. The MJO does suggest (using the GFS model) that the phase, currently in 3 is going to move through 4-5-6-7-8 with a reasonable amplitude. This would give (looking at the 500mb patterns such phases give-see below

http://www.americanwx.com/raleighwx/MJO/MJO.html

the probability of some kind of northerly oubreak sometime beyond day 14-16 from now. All very tentative and perhaps best look to the views of several well read folk in the Stratosphere thread for information on what help for coldies may come from that area of the atmosphere.

So to sum up, cold starts and coldish 'feelin' to some days but no major outbreak before mid December at the earliest in my view. Watch the 500mb anomaly charts, for sure I will post any probable change they may seem to be offering and read the views of several well respected members in the Stratosphere thread for further background signals.

To be fair John,I among with many others are not seeing a major cold outbreak in the near future.We are just going to enjoy the much cooler days and nights to come.The middle to end of December has always been favourite for a major meteorological change in our vicinity.Lets enjoy the winter unravelling.

Edit

You couldn't be more correct about the Strat thread too.A must read before over analysing the volatile day to day model outputs

Edited by winterof79
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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

Looking at the ECM Control in FI, this is the way I hope the pattern will develop:

 

source: here

 

Looking at Reims just NE of Paris the Control suggests cold temps: post-14819-0-66202700-1417355953_thumb.g

 

Bearing in mind ECM D10 over amplification I am not putting much faith in a D15 chart, but it is around the time the PV should hopefully become less dominant in the Greenland/NE Canada area. Plenty of cold runs on the ECM London temps ensembles:

 

post-14819-0-64119000-1417356133_thumb.g

 

So potential is there...

Edited by Paul
Sorry, had to remove the copyrighted ecm image.
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Posted
  • Location: winscombe north somerset
  • Weather Preferences: action weather
  • Location: winscombe north somerset

Good afternoon on the last day of Autumn , fellow posters .generally all output today points to a fairly quiet spell of weather ,Ok it will be turning Cooler as we go through this week with some frosts Fog perhaps some wintryness over fairly high elevations and a promise of some sunny early winter sunshine .but as we approach the later stages of next weekend and early the following week Alot of uncertainty in my opinion .some Data pointing towards an attack from the north /west others saying pressure will be high from azores to europe .But remember last December ,Mother nature was cooking up some pretty spectacular weather .looking at current Vortex modelling and it seems to have very itchy feet but will probably find a place to Roost but Destination currently [unknown ] .as many experienced posters have pointed out keep an eye on model runs over several days as apposed to just One run ,REmember all data whether surface maps upper air maps including Jet stream vortex etc will change constantly ,this model forum i find a very interesting learning area .For new members and those who want to learn more about Meteorology especially those who want to understand upper air patterns and what is actually taking place a couple of miles above our heads could fin d the study of Aircraft contrails a good Tool for visually studying the upper air along with of course natural clouds .If you type in Science of contrails on  Google ,there are many interesting sites .I,v mentioned this on Model output discussion as i know some posters are new and learning .well 13 weeks of winter about to start ,182 ecm runs 364 GFS runs ,not forgetting the others of course ,Cheers gang  :cold:  :drinks:

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Posted
  • Location: Calgary, Canada. Previously, Saffron Walden (Essex/Herts border), United Kingdom
  • Weather Preferences: Continental:Warm dry summers, cold snowy winters
  • Location: Calgary, Canada. Previously, Saffron Walden (Essex/Herts border), United Kingdom

I don't think we should be so quick to trash a northerly on w/c 8th December. The latest run was one of the mildest of the ensembles. Sorry if this has already been mentioned graphe3_1000_324_112___.gif

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Posted
  • Location: Southampton, Hampshire
  • Location: Southampton, Hampshire

Great post, written with the maturity and knowledge I could only dream of having !!

 

To my untrained and very much bedroom enthusiast eye,  Looking further ahead (which always going to be about looking for trends ??), IMO that there really doesn't seem to be one and when there's a lack of trend in the models it tells me that a half way house between what is being shown is the most likely outcome. 

 

To that end I wouldn't be surprised if after this week, we see a continuation of the UK being stuck between High pressure to the West, and High pressure to the East with Low pressure squeezing between the gaps. 

 

Something a bit like what peturbation 12 is showing

gens-12-1-288.png?6

 

 

As you say though anything is plausible I just wanted to find some way of saying that your post was awesome other than putting some one liner that would be deleted :-)

Thank you kindly EML Network. I could just be talking a load of rubbish (not for the first time!) but I tend to trust my instincts when I spot something unusual or in some way significant in the model runs.

You make some valid comments in your post re the movement of HP over the next week or so with cold fronts in between. I think we tend to forget sometimes that a great part of our day-to-day weather is pretty ordinary, but with, it seems, increasing incidence of more extreme conditions. Half the fun of model watching is being able to detect real signs of such events in advance as well as significant pattern changes, which the models don't often do in the >5 day range. But it's all good fun!

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Posted
  • Location: Catchgate, Durham,705ft asl
  • Location: Catchgate, Durham,705ft asl

The 12z UKMO at 120 hrs still going for the short Northerly at the end of the week with -4 uppers covering most of the country which hasn't happened for quite a while.

 

 

 

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Posted
  • Location: Batley, West Yorkshire
  • Weather Preferences: Heat and Snow
  • Location: Batley, West Yorkshire

GFS 12z is pretty awful for the first 10 days, but from day 10 onwards we get ridging towards Greenland and a cold NW flow...

 

gfsnh-0-240.png?12gfsnh-0-276.png?12

 

-8 uppers for the far East of the UK

 

gfsnh-1-288.png?12

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Posted
  • Location: Camborne
  • Location: Camborne

Hard to say, I find those weatherbell charts pretty but annoying to read... to the point I don't bother to click on them.

I wish you'd put up wz charts instead as sometimes you make good sense. ;)

 

I must admit I don't understand this post, popular though it is. Hard to read? I would have thought they were quite easy to read.

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Posted
  • Location: st albans
  • Location: st albans

Sorry MODS if this is in the wrong place. 

BBC forecast for the week ahead and unusually looking at next weekend and a little beyond... the `s` word is mentioned

 

http://www.bbc.co.uk/weather/features/30268791

I assume that's because we will have some cold surface air in place and then the Atlantic fronts will try and move in. Expect it would be transient away from northern hills.

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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

GEM wants to obliterate the PV by D10 and literally anything goes from that setup: post-14819-0-29877600-1417366463_thumb.p

GFS op has the two Storms ready to cause mid-latitude disruption at D8: post-14819-0-37110400-1417366530_thumb.p

Similar to GEM with the US West coast ridge, this should give the Canadian vortex enough of a push to clear it from that area. However all sorts of permutations likely as these two LP systems interact with the jet and cause further HLB's. As we know from recent episodes this may not get resolved till around t-120 so next week could throw up a bevy of solutions. Ties in with potential cold for somewhere in the mid-latitudes in FI. GFS P would be a near miss:

post-14819-0-96263500-1417366951_thumb.p

Edited by i'm dreaming of...
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Posted
  • Location: winscombe north somerset
  • Weather Preferences: action weather
  • Location: winscombe north somerset

Well i,v actually watched the GFS unfold today not usually what i do , certainly looks like our vortex Could be migrating east but as we all know a very unpredictable traveller who likes to park itself in comfortable well known locations where it feels at home ,so a possibility that it Could give us a taste of winter if as modeled today .But cant help but notice high pressure to our s west is also well modeled ,All a real pickle past 7/8 days so lets hope tonights ecm and others can shed some light ,but we are sat i think in a good position for possibilitys, enough changing spread in models also, so fasten your seat belts i think a change is very likely after next weekend but details still to be sorted atleast interesting times gang . :cold:

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Posted
  • Location: Batley, West Yorkshire
  • Weather Preferences: Heat and Snow
  • Location: Batley, West Yorkshire

Day 7 on the ECM is looking far better than the 00z, the Azores ridge is kept well west:

 

ECH1-168.GIF?30-0ECH1-168.GIF?00

 

At day 8 the ridge is moving SE:

 

ECH1-192.GIF?30-0

 

Far better run! :D

Edited by Barry95
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Posted
  • Location: Sunderland
  • Weather Preferences: Hot Summer, Snowy winter and thunderstorms all year round!
  • Location: Sunderland

There are a few off topic and one-liner posts creeping into the discussion.........I'm not going to remove them as we're approaching the season of goodwill and all that stuff.......(actually, I'm just very lazy) but if you can bare it in mind, it'll be much appreciated........cheers  :good:

Edited by ajpoolshark
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Posted
  • Location: Batley, West Yorkshire
  • Weather Preferences: Heat and Snow
  • Location: Batley, West Yorkshire

The Azores ridge is sent packing at day 9, and we are left in a cold NW flow. Polar Vortex is also looking pretty desperate.

 

ECH1-216.GIF?30-0

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Posted
  • Location: Newbury, Berkshire. 107m ASL.
  • Weather Preferences: Summer:sunny, some Thunder,Winter:cold & snowy spells,Other:transitional
  • Location: Newbury, Berkshire. 107m ASL.

There are a few off topic and one-liner posts creeping into the discussion.........I'm not going to remove them as we're approaching the season of goodwill and all that stuff.......(actually, I'm just very lazy) but if you can bare it in mind, it'll be much appreciated........cheers  :good:

 

Sorry AJ and coming from a moderator, I wouldn't setting a good example but all I can say is OMG:shok:  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In fact I'll attach a chart for folks for good measure, this will NOT verify as shown but Christmas would have come early if it even went close for those who like a wintry bite to their winter weather.

 

 

post-7183-0-84586100-1417374163_thumb.gi

 

Off to watch the darts now, goodbye all and behave for AJ.  :drunk:

 

*the chart actually looks better than it what would be produced by it in reality, but who cares* December 1st tomorrow, here we come.*  :hi:

Edited by gottolovethisweather
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Posted
  • Location: HILL OF TARA IRELAND
  • Weather Preferences: SNOW ICE
  • Location: HILL OF TARA IRELAND

I think the signs are there on the Ecm12z and come Tuesday this week I expect the azores high to push back further west it won't take much for that to happen and I believe it will, allowing the cold flood gates to open.

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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

Well ECM are finally modeling the Arctic like GFS and GEM in its later stages. D7-8 the energy sent from the Canadian PV East is being sent back towards it's source. On the last few runs it has drained it to Siberia:

 

0z: post-14819-0-89822200-1417373864_thumb.p 12z: post-14819-0-74449700-1417374610_thumb.p No shock there!

 

At D9 ECM has the Atlantic storm interacting with the jet: post-14819-0-90884100-1417374017_thumb.p

 

At D10 it has blown up that storm and has it on course for the UK and we are in a trough, with heights sinking: post-14819-0-35458600-1417374271_thumb.p

 

One of many possible outcomes no doubt.

 

It is not recurving the Pacific Storm like GEM and GFS though to be fair previous runs it did not even plot this as a deepening system! Lots of uncertainty into week 2.

Edited by i'm dreaming of...
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