Jump to content

Model Output Discussion 4th Dec.2013-12z onwards.


Recommended Posts

What do we think would follow the ECM 240hr chart? Wouldn't the PV eventually slip east and north to its default position? Might be good for high ground in Scotland but little elsewhere IMO

This is my T264hrs chart based on the movement of the PV and that important shortwave running se into Russia, troughing probably over the UK but heights building nw towards eastern Greenland.

 

post-1206-0-45112200-1386620188_thumb.gi

 

It will probably need a few more days if things went well to completely disrupt the troughing and we'd need the upstream pattern to retain enough amplification to help drive the energy se'wards.

  • Like 3
Link to post
Share on other sites
  • Replies 2.1k
  • Created
  • Last Reply

Top Posters In This Topic

Whilst the ECM @ Day 10 is sending a wedge of cold air in from the NW, we are again looking NE towards Scandi for better shaping of the scandi heights-

 

As said best run thus far of that happening-..

 

S

  • Like 4
Link to post
Share on other sites

Two 12z ECM's in a row have showed a North-Westerly at day 10, if they verify the forum would go into meltdown after finally getting out of this pattern.

 

Posted ImagePosted Image

 

 

That is a very graphic post. The difference is staggering (not withstanding there is the difference of a day between the two charts). IF correct, the ridging over Eastern Siberia would pobably be the main driver to an eventual pattern change.

  • Like 1
Link to post
Share on other sites

Good evening everyone. Here is the report of the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Monday Deceember 9th 2013.

 

All models continue the theme of dry and fine weather for the remainder of this week as High pressure is maintained to the SE and Low over the Atlantic. However, NW Britain will be the exception to this with cloudy skies from troughs just to the West with outbreaks of rain at times along with strong winds. It will be mild here. Further South and East it will be brighter with some pleasant sunshine in between cloudier spells and by night clearer skies could give rise to patchy frost and fog in places, slow to clear by day. By the weekend things may begin to turn somewhat more unsettled for rather more of the UK with the East alone staying dry. However, it's here where the models diverge a little in how this transpires.

 

GFS then sets up a very mobile pattern for the second half of the run with rain at times for all. With winds permanently from a positions between South and NW the temperatures will remain quite respectable for December with little chance of significant frost, fog, sleet or snow.

 

UKMO closes it's run for next Sunday with a very deep Low near Iceland with a stronger and strengthening SW flow with most areas having become more changeable with some rain at times, especially in the North and West. Temperatures would remain near to or a little above average for most.

 

GEM tonight brings a change too next weekend with some rain ahead of a decline into potentially quite stormy conditions as intense depressions cross quickly NE over or just to the NW with very wet and windy conditions developing fr all, especially but not exclusively to the North and West. Temperatures would remain close to average but it would feel chilly in the wind and rain next week.

 

NAVGEM also shows a period of more unsettled weather at least for a time with some rain likely for all as winds freshen markedly from the West in response to low pressure crossing East to the north of Scotland. Temperatures look like being close to average overall.

 

ECM tonight shows a much more Wintry looking set of charts for next week as High pressure influence to the SE is lost in preference to deep Low pressure covering the North Atlantic. Very unstable WSW winds would bring spells of rain and showers, some heavy later with thunder and hail as somewhat colder conditions take hold with temperatures close to average at best. Winds would be starong at times too with gales in the North and West.

 

The GFS Ensembles show a steady decline towards more average December levels from later this week with rain developing at times in all areas with time though amounts in the South will be largely suppressed.

 

The Jet Stream tonight's most notable attribute is the strength of it's flow as it powers NE to the NW of Britain through this week. It then shows a continued trend to bring the axis further SE to run NE over the UK next week hence the incursion of more mobile Atlantic weather type with rain and showers and storm systems to the NW of the UK.

 

In Summary tonight there is definitive trend that things may begin to change from the weekend. While we are unlikely to move towards anything wintry in the way of snow and ice we will probably get out of the rut of dry and mild weather as many of us will see this week into something more interesting with wind and rain becoming much more widespread through next week along with some strong West or SW winds at times. Some models do show the effects to the South as still quite limited while others suggest the South will also share in some heavy rain and gales at times. It will be interesting to see how this growing trend develops or subsides again over the coming model runs.

  • Like 4
Link to post
Share on other sites

I wonder if ECM are over amplifying the pattern again on another of their T240 charts. Certainly the 0z run was not as promising. As others have alluded to, the amplification by the Siberian High in the 12z sharpens up the PV. However the high is >1050mb and bearing in mind the UK's record high is only 1053mb I am not sure that this is not another of ECM's over egging the amplification.

 

post-14819-0-07344100-1386620363_thumb.p

 

Neither GFS or GEM make as much of this high, both at 1030mb. The anomaly 500 shows how extreme this is: 

 

post-14819-0-08320800-1386620771_thumb.g Compared to GFSpost-14819-0-85066500-1386620863_thumb.p

 

The ECM mean also makes less of that high and the pattern is a lot flatter:

 

 post-14819-0-88163200-1386620972_thumb.g post-14819-0-93599500-1386621084_thumb.g  .,..mean closer to GFS height anomaly.

 

One to keep an eye on but not convinced.

Edited by i'm dreaming of...
Link to post
Share on other sites

 

At this point in time CC, I'd be happy with a bit of PM air just to replenish the ski resorts here, there was lots of snow towards the last week of November and then its been sunny since, still great conditions now but some of the recent outputs looked hideous with zero sign of precip and higher freezing levels. I agree normally I wouldn't discuss too much  synoptics shown that far ahead but its last chance saloon to save Xmas, theres nothing worse IMO than crappy mild sw'erlies over the festive period, even sunshine and frosts is okay but certainly not zonal mild mush!

I love the run up to Christmas but when it does not even feel like winter letalong Christmas its a big let down. I think the odds on the ECM being on themoney is probably 90/10 against but you just never know.
  • Like 1
Link to post
Share on other sites

http://www.meteociel.fr/modeles/ecmwf/runs/2013120912/ECH1-240.GIF?09-0

 

The best ECM @ day 10 for some while - although day 10 a long way away!!

 

At least something promising though..

 

S

 

Yes Steve, also some signs of some Vortex Pertubation, along with the building HP at NP.

Link to post
Share on other sites

Looking at the ECM ensemble mean and spreads, theres decent support for low pressure to dig further south. Also a cluster of solutions supporting that high in Siberia.

The digging trough is the key imo. We've seen it fail on this week modelling but with some help from the displaced azores ridge pulling back rather than pushing the jet back ne, we would be onto something seasonal at least.
  • Like 5
Link to post
Share on other sites

The digging trough is the key imo. We've seen it fail on this week modelling but with some help from the displaced azores ridge pulling back rather than pushing the jet back ne, we would be onto something seasonal at least.

Yes BA that's really good news, hopefully this trend continues. That's a pretty decent mean chart at T240hrs given what recent days has shown.

  • Like 1
Link to post
Share on other sites

What do we think would follow the ECM 240hr chart? Wouldn't the PV eventually slip east and north to its default position? Might be good for high ground in Scotland but little elsewhere IMO

 

Just in time for Christmas? We'll take it! Posted Image

 

The favourable aspect of such charts isn't so much the exact position, but rather that a large body of high pressure which could be instrumental to delivering cold conditions is hinted at being nearby, let's wait until nearer the time to find out the exact trajectory of any low pressure systems when and most importantly if pressure does indeed build near to Scandinavia / western Russia.

 

It might be more than just a Highland fling (ho-ho) 

  • Like 1
Link to post
Share on other sites

Seems a brighter mood on here. Will have a look through the thread. Need some cheering up after Christmas shopping - a pursuit that is enjoyed only by women!

 

Yes, lets hope we may be seeing a glimpse of light at the end of the dark tunnel!

Link to post
Share on other sites

Seems a brighter mood on here. Will have a look through the thread. Need some cheering up after Christmas shopping - a pursuit that is enjoyed only by women!

 

You couldn't be more right... http://www.dailymail.co.uk/news/article-2520753/Chinese-boyfriend-jumped-death-girlfriend-insisted-going-clothes-shop.html#ixzz2mzqmN3wq

 

Onto the models and we really need to see the PV distrupted in a big way... No distruption = no real cold.

  • Like 1
Link to post
Share on other sites

To keep up with the positive flow the last few posts, I'll give a short analysis of the GFS stratosphere analysis:

 

Below is given the GFS stratosphere heights forecast for the 100 hPa level.

T+168:

Posted Image

 

At T+168, a clear ridge pattern can be seen over central and eastern Europe, giving credit to the blockade curently present over that area. This means that for the next 7 days, the blockade is forecast to persist.

 

However, at T+240, retrogression of the same high can be seen. Depending on how far that high would be able to migrate northward, this could either result in an Euro high or Atlantic blocking. 

 

T+240:

Posted Image

 

What can also be seen is that the PV is moving slowly toward Siberia, which may slightly improve the prospects for cold. (more possibilities for Greenland blocking etc). However, also the pressure gradient over Scandinavia is very sharp, and that could in turn result in a northern jet occuring.

 

EDIT: The 200 hPa streamlines indicate exactly the opposite of above GFS analysis, and therefore, little weight should be given to above forecast.

 

Posted Image

The GFS +240 wind analysis of Europe. It shows troughing to the west of Europe, exactly the opposite of the 100 hPa plot. 

 

It might be that the stratosphere analysis was from the 00z run, while the 12z run is the one given above.

 

Sources:

http://www.cpc.ncep.noaa.gov/products/stratosphere/strat_a_f/#emcz

http://www.wetterzentrale.de/topkarten/fsavneur.html

Edited by Vorticity0123
  • Like 1
Link to post
Share on other sites

There seems to be a clear split in the NAO forecast towards the middle of the month. I would say there are slightly more negative/neutral ens than positive ones. I have checked this daily for the past week, todays negative ens are slightly more negative than they were a few days ago and the positive ens are less positive if that makes any sense. I know these can be quite unreliable at times but I thought I would add something a little more positive into an already more upbeat thread this evening.

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

  • Like 1
Link to post
Share on other sites

Just in time for Christmas? We'll take it! Posted Image

 

The favourable aspect of such charts isn't so much the exact position, but rather that a large body of high pressure which could be instrumental to delivering cold conditions is hinted at being nearby, let's wait until nearer the time to find out the exact trajectory of any low pressure systems when and most importantly if pressure does indeed build near to Scandinavia / western Russia.

 

It might be more than just a Highland fling (ho-ho) 

 

 

Guys I dont know where are you seen all of that stuff... when I look at the GFS and the ECM I always can see amazing stuff after +96hr and then deeply in FI and it never happens.... 

we seem to be chasing a ghost that will never come :(

 

How reliable are the models passed +72hrs?? it doesnt seen to be working very well (for last week, all models were giving snow in the liverpool - Manchester area and we had nothing at all...)

Link to post
Share on other sites

Guys I dont know where are you seen all of that stuff... when I look at the GFS and the ECM I always can see amazing stuff after +96hr and then deeply in FI and it never happens.... 

we seem to be chasing a ghost that will never come Posted Image

 

How reliable are the models passed +72hrs?? it doesnt seen to be working very well (for last week, all models were giving snow in the liverpool - Manchester area and we had nothing at all...)

 

 

A good part of model watching is trend spotting - without it and with no speculation about what is showing in FI, well what is the point in model watching?  The sensible people know to take anything in FI or that far ahead with a lorry full of salt but comment is needed even if it is in this context surely?

  • Like 3
Link to post
Share on other sites

wrt 1962, a lot can happen in two weeks but it would help if we had a nw/se jet and a euro trough as was the case back then.  as the good lord says to the chap who asks for divine help to win the lottery : 'meet me halfway - at least buy a ticket'  !  we are currently struggling to find anywhere to buy our ticket.

  • Like 8
Link to post
Share on other sites

wrt 1962, a lot can happen in two weeks but it would help if we had a nw/se jet and a euro trough as was the case back then.  as the good lord says to the chap who asks for divine help to win the lottery : 'meet me halfway - at least buy a ticket'  !  we are currently struggling to find anywhere to buy our ticket.

Lol, best analogy of where we are what is required.
  • Like 1
Link to post
Share on other sites

Guys I dont know where are you seen all of that stuff... when I look at the GFS and the ECM I always can see amazing stuff after +96hr and then deeply in FI and it never happens.... 

we seem to be chasing a ghost that will never come Posted Image

 

How reliable are the models passed +72hrs?? it doesnt seen to be working very well (for last week, all models were giving snow in the liverpool - Manchester area and we had nothing at all...)

Exactly, a record breaking cold spell could be around the corner for all we know. But people seem to think they can write months off. The famous Winters didn't get going until after Christmas. Also It's not as simple as saying 'the pv is strong so we can't get cold', what an easy job it would be for forecasters if they thought 'lots of purple on this chart, Winter's going to be mild!'

Edited by Barry95
  • Like 4
Link to post
Share on other sites
Guest
This topic is now closed to further replies.
×
×
  • Create New...