Model Output Discussion 23/11/2012 18Z onwards

[itsnowjoke]

Every post of mine is being deleted. I thought this was suppose to be a discussion to learn and discuss.

I'm trying to learn and would like to voice my opinions.

My posts are model related and are not being disrespectful in anyway.

Mods- I won't post again. Clearly unless you speak technical or you are a regular you get deleted.

I know you want to learn as i do, I ask questions from time to time just to be sure of exactly whats going on.

Its a busy time on here at the moment.

Im sure if you ask people on here will be happy to help.

[cooling climate]

Without that shortwave that develops off the coast of Norway you can see how

much quicker the cold air would reach us and how much colder the run would be.

The UKMO quickly dispenses with the shortwave and starts to build a a formidable

looking block to the north which ties in with the updated Mets thoughts and

makes sense when you take into account all other guidence.

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

CPTEC looking good for cold

[SMU]

@ Eagle, Please take a look for the 850hpa temperatures at this picture. You can find the temperature be make a comparison. This picture was made by Alwin Haklander, a meteorologist from the Netherlands. It might be useful!

Seb thats a great chart-

I used 534 DAM line along the 1005 contour- ( im assuming its the 534 DAM line before correction to ACTUAL thickness) so -5c 850 seems around right- maybe a bit colder at -6c.

S

[NickR]

Seb thats a great chart-

I used 534 DAM line along the 1005 contour- ( im assuming its the 534 DAM line before correction to ACTUAL thickness) so -5c 850 seems around right- maybe a bit colder at -6c.

S

At 144 on the UKMO you mean?

So wintry showers a possibility in the East, on higher ground in particular, with snow to lower levels 24-48 hrs later?

[Barry12]

Nice chart

[Troubleatmill]

is it possible that the GFS has programmed in to its computers that shortwaves are so hard to forecast and have so often been spoilers to great synoptics, that it is throwing them in left right and center because they often occur, just whem and where we dont want them. just a thought?

[January Snowstorm]

Again, this is no dig at ANYONE-

People using the GFS to control their posts & feelings really need to evaluate what model they follow- especially in these blocking conditions-

The 12z GFS isnt going to happen.- look at it- where is there anything clean about it.... -- its tainted with shortwaves all over the place & by 140 ish has become pretty unlikely.

The UKMO is clean, seems nice & progressive to a solution that looks plausable.-

Cold from Thursday- steadily getting colder - so pretty much whats been on the cards from day 1.-

S

A lot of the smaller models are backing the UKMO so am happy to say you were right

Tonight was key (and eventhough ECM not out yet) am happy to say we are in a far better place and the gfs looks a load of cannon fodder!

Hasten to add THANKFULLY!!

[chionomaniac]

is it possible that the GFS has programmed in to its computers that shortwaves are so hard to forecast and have so often been spoilers to great synoptics, that it is throwing them in left right and center because they often occur, just whem and where we dont want them. just a thought?

I think that if you have a fair amount of distance between 500 hPa troughs and ridges then it can be quite difficult for models to distinguish the surface based troughs and ridges. And, in particular the GFS seems to have a habit of overdoing this by adding in too many. It is therefore better to look at the overall 500 hPa pattern in these scenarios rather than concentrating too much on the short waves that manifest in mid range.

The 500 hPa pattern up to mid range is still good.

Edited November 24, 2012 by chionomaniac

[Jupiters Winter]

The Usual GFS wobble I have seen over last few years when it comes to East/North Easterlies..... It will start correcting as usual nearing the reliable timeframes. To be honest GFS looks a shambles at the moment, a true shortwave mess.

[weather eater]

Actually the GFS and the UKMO are not poles apart at 144hrs it’s the GFS habit of dropping SWs into the mix that’s making all the difference. Let’s be honest here, this is something the GFS does a lot, adding and often over developing SW features its one of the reasons it always ends up in a mess in FI, the GFS breeds them like rabbits.

[PubliusEnigma]

Heres an interesting one-

UKMO 144

http://www.meteociel...44-21.GIF?24-17

BOM 144 00z

http://modeles.meteo...nh-0-150.png?00

BOM 192 00z

http://modeles.meteo...nh-0-180.png?00

note the vertical advection over greenland.

Its been a good start to the afternoon excluding the volatile GFS

S

Do you think the BOM is more reliable than the GFS ??? I've of the opinion

that its still very much undecided. The trend to colder weather than present is on the way.

Until the ECM starts erring towards the GFS or supporting the UKMO, its unwise to be

overly confident that snow in many places is on the cards. The output from the GFS as you

said, is messy. The ECM, is a bit wobbly, the UKMO solid and 'clean'. Looking back to

winter 2011 did we see the 'clean' synoptics or did we more often than not see annoying

shortwaves cropping up diverting easterly and northerly flows around the UK ? My heart

wishes for the clean UKMO evolution, my mind says that a less clean or unclear evolution

will result probably taking another 7 to 8 days before its established.

[PubliusEnigma]

http://www.wetterzentrale.de/pics/Rtavn19217.png

Sub Zero temps at midday, across Scotland, in a weeks time !! :o

[phil nw.]

At this busy time please try and keep your views based around the model outputs.

We don`t wish to dampen enjoyment by deleting anyone`s posts but sometimes it`s essential to avoid the thread being clogged up with irrelevant comments.

Thanks all

[SMU]

Do you think the BOM is more reliable than the GFS ??? I've of the opinion

that its still very much undecided. The trend to colder weather than present is on the way.

Until the ECM starts erring towards the GFS or supporting the UKMO, its unwise to be

overly confident that snow in many places is on the cards. The output from the GFS as you

said, is messy. The ECM, is a bit wobbly, the UKMO solid and 'clean'. Looking back to

winter 2011 did we see the 'clean' synoptics or did we more often than not see annoying

shortwaves cropping up diverting easterly and northerly flows around the UK ? My heart

wishes for the clean UKMO evolution, my mind says that a less clean or unclear evolution

will result probably taking another 7 to 8 days before its established.

Within the cleanness there is usually the odd shortwave- not 5 or 6 though,,- remember we are all looking at the NH now as opposed to 2 years ago- probably just the window of NW europe.-

I doubt the BOM varifies better than the GFS, but even a blind squirral finds his nuts sometimes,....

THere is a distinct difference in the models tonight & again I cast my eyes towards my favourite area of this winter ( & probably future ones) western greenland)

once you get the CORE of a system NW of the southern tip ( as opposed to south & east) then thats a HUGE domino effect for the UK depending on the angle of amplification.

UKMO Greenland 144

http://www.meteociel.fr/ukmo/runs/2012112412/UN144-21.GIF?24-17 PROMOTING BLOCKING

GFS Greenland 144

http://modeles.meteociel.fr/modeles/gfs/runs/2012112412/gfsnh-0-150.png?12 ENERGY JUST GETTING THROUGH-

S

Edited November 24, 2012 by Steve Murr

[bobbydog]

just like to point out, for those craving the view into the 'future' that the GFS gives but for the UKMO, as was mentioned earlier today, the BOM is a slightly lower res version of the UKMO.

as the GFS is apparently inconsistent at the moment, the UKMO is the one to watch up to +144, then the BOM for anything afterwards as it is a (rough) continuation of the UKMO

http://www.meteociel.fr/modeles/ukmo2.php?carte=1021&ech=18&archive=1&nh=0

http://www.meteociel.fr/modeles/bome_cartes.php?ech=6&code=0&carte=0&mode=0&archive=0

if that makes sense.....!

[phil nw.]

Actually the GFS and the UKMO are not poles apart at 144hrs it’s the GFS habit of dropping SWs into the mix that’s making all the difference. Let’s be honest here, this is something the GFS does a lot, adding and often over developing SW features its one of the reasons it always ends up in a mess in FI, the GFS breeds them like rabbits.

Yes i agree WE.

The overall pattern between them at T144 is not dissimilar apart from those blessed shortwaves and along the lines of the earlier height anomaly outputs.

[AWD]

The GEM makes quiet a lot of the trough to the east at T144, with an "arc" of heights going around it.

http://www.meteociel.fr/modeles/geme_cartes.php?&ech=144&mode=0&carte=1

[mulzy]

At first glance, the 12z GEFS are 'better' than the 6z set.

http://modeles.meteo...21-1-192.png?12

Edited November 24, 2012 by mulzy

[chris55]

Solid UKMO, three very consistent runs now,

As others have said it will be interesting to see where the BOM goes this evening as if it follows UKMO it could gives us an idea of what may evolve from 144 if the UKMO was to verify..

GFS seems to be quite volatile between runs, however it can by no means be discounted. ECM will throw some more uncertainties into the mix, but a follow on from UKMO would be nice!

[weather eater]

Just to emphasis the point here they are.

[chris55]

The GEM makes quiet a lot of the trough to the east at T144, with an "arc" of heights going around it.

http://www.meteociel...&mode=0&carte=1

This has been a theme of the ECM in recent runs, to me it looks unlikely, but we'll just have to wait and see.

[Frosty.]

Well the Gfs 12z op run is very messy but at least it brings an early taste of winter with some snow around and widespread frosts by the end of next week, it then rather loses it's way from around T+240 but it still looks cold, temps only 2-4c with a mix of rain and sleet with snow on hills, but i'm not going to say anything else about the gfs run because it appears to lose the plot, compared to what the meto are indicating. The ukmo 12z shows a cleaner and smoother transition to cold from the northeast/east, there are still some problems with shortwaves on gfs but a major pattern change is very much on course with increasing risk of snow showers, sharp frosts and high wind chill as the airflow becomes continental arctic, we would now be very unlucky to miss out on a significant cold spell with a really potent cocktail of wintry weather.

In the meantime, another prolonged spell of torrential rain moving north and east across england and wales, turning to snow or freezing rain on hills as it reaches scotland, a wet and cold day in the more northerneastern parts of the uk tomorrow, a brief window of fine weather further south before the next batch of heavy rain spreads from the southwest later tomorrow, yet more heavy rain on monday and probably on tues/wed further southeast so the flooding set to continue, gradually brighter, colder and more showery weather spreading from the north during next week with the showers increasingly having a wintry flavour by the second half of the week, even colder by next weekend and the following week with snow, freezing fog and sharp frosts if things go fairly according to plan.

Edited November 24, 2012 by Frosty039

[AWD]

Wonder if there is a chance if back edge snow tomorrow over northern areas;

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=gfs&MODELLTYP=1&BASE=-&VAR=weas&HH=24&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

Wonder what the GFS is seeing?

[SMU]

http://www.wetterzen...cs/Rukm1441.gif

last one from me before the ECM

552 DAM over svalbard- in terms of the last 12 years - thats the last hens tooth to fall...

S

Edited November 24, 2012 by Steve Murr