Model Output Discussion 19th January 2014-18z onwards.

[IDO]

I noticed a few conversations on Twitter over the States where there is a similar model discrepancy. Suggestions that the EC op US trough is too deep for too long, so not keen on them.

 

This ties in with the amplification of the Atlantic ridge for our west that stopped the slider scenario. It already looked an outlier compared to the mean so maybe a better ecm tonight? 

 

Current squall line with thunder and lightning:   source

[Mucka]

What to make of today's output before this evenings runs?

Some very mixed signals with the opposite extremes being UKMO and GFS and  the other models falling somewhere between but JMA and GEM leaning more toward something wintry than ECM.

If we look at the ECM London ensembles we can see the ECM Op was yet another progressive run within its suit and it is actually above the  mean almost from the get go and gets slowly wilder from there so put no faith in that unless we get some run to run consistency.

 

 

Speaking of consistency the UKMO has been outstanding in this regard which is why, although it is a little out on its own re strength of block and Easterly flow, it still commands respect.

If it is wrong then there is really very little time for it to begin its backtrack and one would imagine that would start this evening, tomorrow morning at the latest so this evenings and tomorrows runs should shed some light on the situation.

 

Knife edge situation for the UK as to whether we see some widespread snowfall to low levels from around middle of next week but it will feel more like winter at least with at least some wintriness for some but equally there will almost certainly a fair bit of disappointment depending on location and altitude.

 

 

Eyes down, fingers crossed. 

[picog]

hello, first post in here, sorry if wrong thread.....but while its quite, can someone explain what the triangles mean...thanks

If they are blue, sleet. If they are green, it might be hail?

[winterof79]

Not ruliing out anything and if you read my post I did say up north there is a chance of snow, also ENS for the north follow pretty much a similar pattern

If you are not ruling out anything,then why not balance your post up with a chart from the colder output.Again your only reference is the GFS which has churned out two totally different runs on the 00z and 06z as Steve Murr referenced.

http://www.meteociel.fr/ukmo/runs/2014012500/UW144-21.GIF?25-06 Maybe not the correct outcome but has consistantly progged it.

[Barking_Mad]

Looks like potential for more snow at low levels in the early hours of Monday morning down through the NW and Midlands and perhaps further south.

 

Edited January 25, 2014 by Barking_Mad

[Purga]

Hi Purga, I must admit that I find your post slightly odd in certain aspects, first of all as already reported, your post is quoting the London ensembles which given it's geographical location is hardly indicative of your rather sweeping initial sentence, secondly the ensembles show a broad scatter early on in the piste with a large disparity at T120 (A 14 degree scatter in T850's illustrate this IMHO) and thirdly, this scatter sums up the model outputs quite well to date in as much as nothing is nailed down with a huge amount of 'model speculation' for want of a better phrase. In summary, whilst everyone is entitled to air their views on the model output, your sweeping statements based on one location ensemble does rather leave you rather wide open to be shot down....

Hi AJ thanks and I take your comments on board. I should have posted ENS for the other areas eg Manchester, Aberdeen, which I have now done in answer to another post. I did mention that I think the north / north east had the best chance of seeing some snow next week but I'm not confident on the longevity of it nor what might happen further south. Much of my viewpoint is coloured by the stance of the METO and their mid - longer term outlooks which suggest no prolonged or significant cold spell. I appreciate your courtesy and tolerance of my views which are not 'popular' but sincerley reflect what i see in the model outputs, 'flawed' as I am sure they are but this is a great fun forum after all for weather enthusiasts. Cheers

[winterof79]

I feel that situations like this will show why the ECM is King, expecting the UKMO to back off on the 12z, although prepared to be wrong... it could hang on for a little longer before backing down or end up being right which will be a real trophy in the cabinet for the model. But I don't think so, anyway here we go.

So in a nutshell ECM is right .UKMO will back off this pm but it may not.You feel you are correct but you may not be.......

Welcome to the thread newbies.Incidently,which of ECMs differing outcomes do you prefer over the last few days?

[shaky]

Looks like potential for more snow at low levels in the early hours of Monday morning down through the NW and Midlands and perhaps further south.

 

well well euro4 model did not show that!!surprising really!!

[Blake]

GFS 12z updating, seems marginally west!

 

http://www.meteociel.fr/modeles/gfse_cartes.php

[Purga]

If you are not ruling out anything,then why not balance your post up with a chart from the colder output.Again your only reference is the GFS which has churned out two totally different runs on the 00z and 06z as Steve Murr referenced.

http://www.meteociel.fr/ukmo/runs/2014012500/UW144-21.GIF?25-06 Maybe not the correct outcome but has consistantly progged it.

Look back I posted the ECM ENS for Reading earlier and commented on the colder trend showing but a lot of scatter. I also posted the UKMO chart for +144hrs and said what a great chart it looked - I don't want to keep repeating the same post!

Edited January 25, 2014 by Purga

[Mucka]

GFS with tiny correction of the jet south to SW of Greenland (more in line with UKMO) at 48h but the differences are still obvious at 60h, quite surprising really for such a short range. (See how GFS has the streak heading on a less souterly track SW of Greenland)

 

Edited January 25, 2014 by Mucka

[bryan629]

so just before this evenings op begin to run .... a lot of people are looking at t=96 as being roughly FI , hence anything after that is leading to an awful lot of uncertainty here...there are currently out  of five models two in agreement with each other and three that think otherwise..ie ukmo, jma versus ecm,gfs and gem.

 

no one knows which to follow as being the best to follow...hence the confusion/uncertainty.... which is being brought about by the handling of the low which is currently fast approaching and making its prescence felt.

 

lets just for now compare two models....the ukmo and the gfs @72 hrs

 

the differences are very obvious ... take a look..

 

firstly gfs at the 00z  had the scandi high a little further south than the 006z...it is slowly being shoved n/nw

the ukmo has the scandi quite a bit further north ....which later in the run allows for caa to run much further west than the gfs.

 

now lets have a look at the pv...gfs has it much more forbidding than ukmo but with the azores ridge cutting of the low ,albeit temporarily.but its stopping our low to move south or shal we say delating its progress south

the ukmo does not have ridging and a better jet profile, also the pv looking a little bit more lame ,but energy still pulsing with a clear run out into the atlantic and forcing our low under a block which is much better postitioned more favourably north which allows for caa to cross over th uk..

 

have a look.

 

so my punt is to watch the gfs slowly pull heights to our east a little bit further north...because if it does then it adds credence to the ukmo being more accurate in later frames

 

[SMU]

http://modeles.meteociel.fr/modeles/gfs/runs/2014012512/gfsnh-0-90.png?12

 

I smell snow for the SE.

 

GFS a good 300 miles west @ the same timeframe & a bigger sweep west of the cold air.....

 

S

[TSNWK]

GFS has shifted a little west around 84 hours.. Hold tight folks, and you know what it's nice to be in this position whereby we are micro managing a run through from its early stages...

[Tim Bland]

Latest GFS looks good for an easterly flow starting midweek. Afternoon Meto update for south east says "easterly winds and wintry showers" so far so good....please don't back down ukmo!!

[bryan629]

 

there you go point prove, with a little bonus as well... heights a little further n/nw and a bit stronger too.. gfs is work in progress at the moment ... im inclined to think ukmo and jma are more on the ball than the other 3.

[weather eater]

Usually we get a blow by blow, frame by frame commentary, why do I feel there's a pile of people out there biting their nails and talking in hushed voices, not bad in my book at 90hrs, better at 102hrs.

Edited January 25, 2014 by weather eater

[The Eagle]

Slightly better so far from the GFS at 72 hrs. Middle of UKMO and GFS seems to be where we are heading in the end.

[Summer Sun]

Improvements on the 12z from GFS

 

 

06z

 

 

12z

 

 

06z

 

Edited January 25, 2014 by Summer Sun

[Eskimo]

GFS 12z has things about 200 miles further West, certainly better!

Edited January 25, 2014 by PerfectStorm

[chionomaniac]

Hmm is that more than a hint of the UKMO output in the 12Z GFS?

 

Looks like it.

[shaky]

Brilliant improvement on the gfs!!ukmo same so far!!low pressure maybe slightly further north at 60 hourw but thats about it!!

[Joe Levy]

Whilst the specifics of such an event are so finely balanced, betting on small changes is risky. However, the GFS 12z is considerably further west than the 6z and is exactly the sort of correction we need to see, as well as greater consensus between the models. My three 'c's: correction, consensus, cold

[cooling climate]

Looks to me like a substantial swing towards the UKMO

from the 12zGFS this afternoon.

[chionomaniac]

I don't think that we need look too much further than T+120 - already a big jump westwards in this timeframe and that is good enough for me! Waiting for the FI strat output now.