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Model Output Discussion 1200 hrs 15/11/14


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The GEFS T240 anomaly.

 

Some upstream amplification, trough Pole/Greenland and swathe of HP eastern seaboard through to eastern Europe. The jet basically funneled between the two Atlantic systems Upshot of this on the surface is not much change in the overall picture with LP Iceland area and HP below. Temps a little below average.

 

Moving on into the future the main indication is that the Pole/Greenland trough will move east and south and possibly disrupting the HP to the south and could introduce an easterly. Oh.

Charts weatherbell (for those that can read them)

post-12275-0-59523600-1417374612_thumb.p

post-12275-0-78627600-1417374620_thumb.p

post-12275-0-03341900-1417374630_thumb.p

Edited by knocker
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Hmm, I'm going to dissent and say that I think the charts tonight are very poor really. The ECM 240 is very much in line with the picture being painted on most of the GEFS. I felt yesterday that there was a trend to pull the Azures high further west but this hasn't really been followed through today and the trend over the last 48 hours has been towards a flatter zonal flow.

Of course things are different to last year in many ways but there are no signs of anything notably cold out towards mid month. the strat may change things down the line and it will be interesting to see what happens there, especially with METO suggesting the balance of probabilities lies with a warmer than average winter. I'm guessing they are not really factoring in the strat side of things yet.

Jason

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Quite a nice run from ECM tonight, pretty much sub-zero uppers all the way through. Its lovely to see the UK covered in blue!! Welcome back winter :D

 

was just wondering if the low pressure at the end would bring us snow next Monday/Tuesday? We'd have been in -4 850s for a couple of days and then the fronts and showers would come through in cold air too?

 

Id hope for some wintryness at least on hills quite far south?

 

ECM1-216.GIF?30-0ECM0-216.GIF?30-0

 

Upon closer inspection, the uppers are actualy -5 from Midlands northwards, with pockets of -6 tucked in there:

 

ECU0-216.GIF?30-0

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Guys, i remember Chiono mentioning on the strat thread that he was expecting this to happen the first half of december. Something to do with MJO phases and wave breaking meaning there was going to be a couple weeks of flat zonal before the fun and games around 15-20th Dec. Does anyone else remember hearing something like this? 

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Hmm, I'm going to dissent and say that I think the charts tonight are very poor really. The ECM 240 is very much in line with the picture being painted on most of the GEFS. I felt yesterday that there was a trend to pull the Azures high further west but this hasn't really been followed through today and the trend over the last 48 hours has been towards a flatter zonal flow.

 

If you compare the ECM 12z today from yesterday, you will see that the Azores high has been pushed further west, compare day 7:

 

ECH1-168.GIF?30-0ECH1-168.GIF?12

Edited by Barry95
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Some off topic posts have been removed and one other post moved here

https://forum.netweather.tv/topic/69782-weather-in-the-general-media-newspaper-features-etc/page-199?hl=%2Bmedia+%2Bthread#entry3076022

 

which was about the BBC weather forecast for the week ahead.

 

Please only your views on the model outputs in here -thanks all.

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Hmm, I'm going to dissent and say that I think the charts tonight are very poor really. The ECM 240 is very much in line with the picture being painted on most of the GEFS. I felt yesterday that there was a trend to pull the Azures high further west but this hasn't really been followed through today and the trend over the last 48 hours has been towards a flatter zonal flow.

Of course things are different to last year in many ways but there are no signs of anything notably cold out towards mid month. the strat may change things down the line and it will be interesting to see what happens there, especially with METO suggesting the balance of probabilities lies with a warmer than average winter. I'm guessing they are not really factoring in the strat side of things yet.

Jason

I have to agree with you. Theres no sign of any deep cold being able to head sufficiently south and PM air really doesn't cut it unless you're high up, the models especially the GEFS tend to overplay the southwards extent of cold upper air at longer range.

 

This is especially when this cold advection is not in connection with HLB, the pattern over the USA is expected to be flat zonal for at least the next ten days, in terms of positives from the output at least the Azores high is expected to remain displaced to the west and the PV although reforming to the north is then expected to break up so in that sense it doesn't at this stage look like a repeat of last Decembers mildfest.

 

At this point looking at the overall set up if the high remains displaced to the west and the jet tracks se into the UK then that may eventually develop some interest if the upstream pattern improves.

 

The output's not the worst I've seen but just a bit underwhelming. At least there will be a cool down into the start of December and mainly dry for the next week so its not all bad.

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The polar vortex still looks to be oscillating between northern Russia and Canada. The ECM does bring in more unsettled and cooler conditions as high pressure slowly recedes west into the Atlantic. At this moment there isn't enough amplification in the Atlantic to really deliver anything which could bring widespread snowfall to lower levels. Though if the ECM is right then the higher ground even in the south could see something a little wintry as polar maritime air becomes established.

Seems to fit ok to me, I felt a more unsettled middle third of the month could be on the cards before we start to open the gate to much colder conditions potentially.

ECM1-168.GIF?30-0

ECM1-216.GIF?30-0

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subtle differences in the UKMO output at +120, in just FIVE DAYS time giving us a direct Northerly, or at least NNW feed.

 

UKMO + 120

UW120-21.GIF?30-18

ECM + 120 has the High pressure's influence covering the entire country (or thereabouts), and so the feed has more of a  Westerly component to it.....

ECM1-120.GIF?30-0

JMA + 120 even more progressive with the influence of the High encompassing the entire country, the cold air kept well to the north of the UK.....

J120-21.GIF?30-12

GFS Control run is probably close to the money being a half way house in between the other models, with the West of the UK being more under the influence of the High and the East having more of a northerly component .....

 

gens-0-1-120.png?12

 

This all of course just a snapshot in time for the end of the coming week, I'd take the UKMO evolution for being more favorable for a route to cold thereafter, mostly due to the fact that the High pressure to our West is organised in such a way that it could theoretically have it's energy shunted north to Iceland allowing the Low pressure that is NW of Scandi to drop opening the doors to a potent NE feed. 

 

So as others have said, there is STILL potential in the output, just because we are not seeing it programmed doesn't mean it's not there.

 

It's only when there is no plausible evolution to cold that we should start to sigh, were not there yet, but it could just as easily to the way of the pear in the next week, options options options, far better than this time last year for sure. 

 

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I have to agree with you. Theres no sign of any deep cold being able to head sufficiently south and PM air really doesn't cut it unless you're high up, the models especially the GEFS tend to overplay the southwards extent of cold upper air at longer range.

 

This is especially when this cold advection is not in connection with HLB, the pattern over the USA is expected to be flat zonal for at least the next ten days, in terms of positives from the output at least the Azores high is expected to remain displaced to the west and the PV although reforming to the north is then expected to break up so in that sense it doesn't at this stage look like a repeat of last Decembers mildfest.

 

At this point looking at the overall set up if the high remains displaced to the west and the jet tracks se into the UK then that may eventually develop some interest if the upstream pattern improves.

 

The output's not the worst I've seen but just a bit underwhelming. At least there will be a cool down into the start of December and mainly dry for the next week so its not all bad.

Nicely summarised - nothing exciting on the agenda for the next week or so, a bit more a kin to Decembers of the 80's.

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Latest NOAA 8-14 dayer - could support a trough to our north bringing NWlies down from the tip of Greenland = hill snow in the north & west?

 

814day.03.gif

Of course it could happen but I cannot see how the chart you show can be seen to support a trough? Perhaps you are seeing the smallish -ve heights suggested as that means. Bear in mind it is an anomaly in itself and that the normal value of the 500mb height in that region is already lowish?

Please don't misunderstand me but the anomalies, I know that is the title of the output, are best ignored unless they are fairly large and coincident with marked troughing or ridging in the predicted contour lines.

Edited by johnholmes
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Of course it could happen but I cannot see how the chart you show can be seen to support a trough? Perhaps you are seeing the smallish -ve heights suggested as that means. Bear in mind it is an anomaly in itself and that the normal value of the 500mb height in that region is already lowish?

Please don't misunderstand me but the anomalies, I know that is the titale of the output, are best ignored unless they are fairly large and coincident with marked troughing or ridging in the predicted contour lines.

 

Would this evenings ECM be quite a good example of what you are saying John. A weakish trough  translates to this surface anomaly or am I not picking you up correctly? I'll add the global ECM and GEFs and you can see they are handling the Greenland trough quite differently

Charts courtesy weatherbell.

post-12275-0-07098000-1417385737_thumb.p

post-12275-0-57500300-1417385743_thumb.p

post-12275-0-03861600-1417385755_thumb.p

post-12275-0-86927900-1417385767_thumb.p

Edited by knocker
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The slider low modelled over a week ago to enter the Med in now in place. The flow over the SE Uk has backed to the NE. It is still mild at present but upwind over the near continent snow grains are starting to be reported with temperature close to zero. This colder air although likely to be somewhat modified by its passage across the southern N sea and also by turbulent mixing with warmer layers above is still likely to be alot colder than anything experienced so far this autumn.

http://meteocentre.com/analyses/map.php?lang=en&map=eur_full&area=eur&size=large

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[Where or when have you seen the METO forecast for our UK winter..just asking..because i would love to see it..for my locale,liverpool, the METO are suggesting a cooler start to winter than usual..please post a link with the METO forecast for winter, many thanks quote name=Jason M" post="3078250" timestamp="1417375124]Hmm, I'm going to dissent and say that I think the charts tonight are very poor really. The ECM 240 is very much in line with the picture being painted on most of the GEFS. I felt yesterday that there was a trend to pull the Azures high further west but this hasn't really been followed through today and the trend over the last 48 hours has been towards a flatter zonal flow.

Of course things are different to last year in many ways but there are no signs of anything notably cold out towards mid month. the strat may change things down the line and it will be interesting to see what happens there, especially with METO suggesting the balance of probabilities lies with a warmer than average winter. I'm guessing they are not really factoring in the strat side of things yet.

Jason

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I see the chance of cold from that chart lying with depressions becoming cut off to our se and as the Atlantic high ridges across the top, it could drag in some cold uppers from our east.

 

I think that is pretty unlikely. I will post in more detail tomorrow morning with a couple of charts and my reasons.

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The slider low modelled over a week ago to enter the Med in now in place. The flow over the SE Uk has backed to the NE. It is still mild at present but upwind over the near continent snow grains are starting to be reported with temperature close to zero. This colder air although likely to be somewhat modified by its passage across the southern N sea and also by turbulent mixing with warmer layers above is still likely to be alot colder than anything experienced so far this autumn.

http://meteocentre.com/analyses/map.php?lang=en&map=eur_full&area=eur&size=large

 

Sorry to be pedantic it is not a slider low but a low that developed on the jet stream, if you look at the latest 200mb chart from GFS you can clearly see the sub tropical jey it is associated with

yes knocker the pattern looks about what you would expect to me

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Nothing has changed since my last post, good riddance mild muck, hello and welcome to relatively much lower temperatures, especially overnight with frosts becoming more widespread along with fog patches which may linger in places with temps not much above freezing. A cold Northerly incursion is still likely by the end of the week with showers turning wintry in the north and looking further ahead, more frosts and the best of the fine weather in the south, more generally unsettled further north and west with average temps and persistent rain interspersed with colder,brighter and showery weather with night frosts..at last a seasonal spell during the early stages of winter 2014-15. :-)

 

Frosty, why do you think a Northerly is likely? All I can see on the models is a North Westerly, which would only bring hill snow. I would love to be proved wrong, but I can't see snow for lower levels in at least the next 10 days. I agree it's great to have got rid of the mild, but I want snow! :D

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Frosty, why do you think a Northerly is likely? All I can see on the models is a North Westerly, which would only bring hill snow. I would love to be proved wrong, but I can't see snow for lower levels in at least the next 10 days. I agree it's great to have got rid of the mild, but I want snow! :D

Just my opinion factoring in how the various models are currently looking by the end of the week ahead, perhaps more NWly with high pressure to the south west and low to the northeast..and latest met office update again mentioned a colder and brighter Northerly incursion into next weekend. :-)

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I wouldn't normally wheel out the NAVGEM and CMA but since its the only thing remotely interesting in the output then desperate times call for desperate measures!

 

The UKMO has that colder dig of air southwards at T120hrs, the GFS and GFS P together with the ECM are reluctant to hold back the troughing upstream and flatter, even the UKMO just offers a short window but you can see from the T120hrs fax chart the sub 528 dam behind the cold front, several troughs shown so if by some miracle this verifies then a chance for some wintry showers especially into Scotland, snow to higher ground:

 

post-1206-0-23232900-1417388403_thumb.gi

 

The support for the UKMO really only comes from the NAVGEM 18hrs and CMA 12hrs output, which is why I put the " desperate times" clause in place !

 

The ECM ensembles at T120hrs have limited support:

 

post-1206-0-93416300-1417388625_thumb.gi

 

It's a shame the models are being so miserly, they could have at least held back the flat tide about to engulf the USA to at least deliver some interest for a few days, anyway enough of my griping!

 

In terms of the ECM ensembles longer term the main cluster still looks on the cold side for De Bilt:

 

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

 

As I'm now really desperately digging for some interest past the mini cold snap of the UKMO( if it verifies), the one straw to clutch from my emergency Christmas Collection is if the Azores high remains displaced with jet running se that something might develop to the ne.

 

 

 

 

 

 

 

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