Model Output Discussion 13/11/12 18Z onwards

[chionomaniac]

Right, new model thread.

Please discuss the latest output. Please keep posts relevent, no off topic posts, and back up your posts with links/ attachments where appropriate.

And please, please no trolling.......

[Ice BIast]

I thought I'd throw in todays JMA. Lots of potential for cold on this chart.

http://www.meteociel.fr/modeles/jma/runs/2012111312/JN192-21.GIF?13-12

[Cloud 10]

Interesting post from Lorenzo in the last thread about the gfs super-ensembles,been searching in

vain for those charts for ages!

Climate Prediction Center - Upper Air Tools

Nice to have some new data to lust over.

[ITSY]

whether the ECM or GFS evolutions, the general FI picture (as in post T+168) looks increasingly like something coldish is on the way. whether that be a cold snap, a northern toppler or a prolonged arctic or easterly blast, the picture has grown more encouraging over the last 24hours. Ordinarily I'd lurk way on the side of caution, but the bullish nature of the BBC forecast and the ECM32dayer make me more optimistic. Only time will tell though.

[summer blizzard]

Models certainly trending colder, in particular the GFS and ECWMF doing well on a hemispheric scale.

Also of note is that 201 members are reading this topic.

[Ice BIast]

Big changes in the small low in the atlantic - much weaker and takes much longer to travel east.

http://modeles.meteociel.fr/modeles/gfs/runs/2012111318/gfs-0-114.png?18

Surely this will have an effect down the line.

[weather_it_will]

Vortex at T126 is smashed to pieces compared to 12Z

[Allseasons-Si]

Much more avection/amplitude on the 18z at 138hrs than the 12z,intresting

the 12z

the 18z

Edited November 13, 2012 by allseasons-si

[johnholmes]

Big changes in the small low in the atlantic - much weaker and takes much longer to travel east.

http://modeles.meteo...fs-0-114.png?18

Surely this will have an effect down the line.

IF it is correct it may. Consider this: the 18z for 12z Sunday is different to what GFS showed for the same time at 12z, and also different to what Met and ECMWF showed. It is only into day 4+ so confidence must be fairly low in the 18z at this time range in my view?

[SMU]

Here we go - High up in the gap-

http://modeles.meteociel.fr/modeles/gfs/runs/2012111318/gfsnh-0-174.png?18

S

[johnholmes]

Steve-for a simple soul like me what on earth is that about please?

[bluearmy]

Quite different jet profile to our south on the 18z run. Sypnotically doesn't look so different.

Steve-for a simple soul like me what on earth is that about please?

Look a the pole John

[Allseasons-Si]

shortwave much weaker at 180hrs,now lets see what follows,undercutting springs to mind.

[johnholmes]

ah ta muchly-I think!

[Paul]

For those guests and new members who are reading and wondering where to the view the models, you can access them all freely here:

http://www.netweather.tv/index.cgi?action=nwdc;sess=

[SMU]

Steve-for a simple soul like me what on earth is that about please?

Expecting the block to ridge North towards Svalbard-

the tilt of the low is negative so its not going to cut off the ridging by sending a shortwave east across Scandi-

From here

http://modeles.meteociel.fr/modeles/gfs/runs/2012111318/gfsnh-0-168.png?18

to Here

http://modeles.meteociel.fr/modeles/gfs/runs/2012111318/gfsnh-0-192.png?18

note the ridge moving NW towards Svalbard ( 1020 MB )

S

[joggs]

High in gap where Steve? regards

High in gap where Steve? regards

Ignore, cheers JH

[SMU]

Not to be on the pub run tonight....

hey ho. onto tomorrow.

night-

S

[bluearmy]

Looks very odd hemispherically in fi. Doesn't fit with the general extended ens modelling

[Snowy Easterlies]

the 18z decided to stay sober tonight and churns out mediocrity

i respect Steve's input but i think he should wait until a run is completed before getting carried away

[Allseasons-Si]

blhhh!

the pub run

better luck tomorrow guys and all

still fi and more chopping and changing to be done untill we hit the reliable but the trend is still there,don't loose sleep over it,goodnight all.

[nick sussex]

What a surprise as soon as the GFS hits the lower resolution output it decides to suddenly change the tilt of the trough.

Earlier it took a different route but the end result was still the jet heading towards Africa so this signal does look strong. Certainly the trough near or to the west of the UK looks nailed on, its just what happens after that which is still uncertain.

[damianslaw]

To the here and now first - its a rather benign outlook with a mild southwesterly/westerly airflow dominating through the rest of week, though temps will ease back down closer to normal values for the time of year. The weekend will see a band of heavy rain move across northern and western parts becoming much weaker as it hits eastern and southern parts.

Into next week whilst we maintain the atlantic influence the models are suggesting the longwave trough will languish to our west thanks to the jet taking yet again another dip southwards... this has been the theme more or less since April and there are no signals suggesting the upstream pattern is about to change significantly anytime soon.. if it was going to do it with gusto it would be now - mid Nov is the optimum time for the polar vortex to ramp into fifth gear.. but it doesn't like happening anytime soon and it is the combination of the position of the jet and position and strength of the polar vortex which is giving reason to why the models are a number of long range forecasts are suggesting a strong probability of something much colder to end the month.

I'm away for a number of days now, and it will be interesting to see whether this suggested cold spell is about to surface.. its good sometimes to take a few days off model watching, quite often on return viewing you are welcomed with a surprise.. I am a cold snow lover and if we do see a build of pressure over scandi and then into greenland at the end of the month this would be a very unusual synoptical development for the time of year when westerlies are at their yearly maxim, the way the weather has behaved since April i.e. strong heights over the arctic/greenland for very lengthy periods and the longwave trough anchored over the country, does raise the odds of such a synoptical development happening markedly I feel..

[Geordiesnow]

the 18z decided to stay sober tonight and churns out mediocrity

i respect Steve's input but i think he should wait until a run is completed before getting carried away

What are people expecting exactly? Theres nothing to really write home about in terms of our weather in the short-medium range. I'm kind of relieved the pub run did not deliver a cold shot as its mis-leading seeing random cold charts being posted when we all should know it will disappear in the next run.

People have been hinting at the end of November for something more interesting, and whilst theres hints of some sort of blocking, its hardly convincing and none of it really appears until after over 200 hours.

The outlook looks fairly straight forward until the weekend, the only question mark will be will that low for Sunday actually make it to the UK and if so when and what strength? Compared to previous runs, the GFS has completely downgraded the strength of the low whereas the ECM does not even want the low to enter the UK as its starts to get blocked off by increased pressure in SE parts of Europe again.

I honestly see little sign of any cold weather for the foreseeable future, although there may be a quick PM shot for Friday night into Saturday which may deliver snow showers into the Scottish highlands but apart from that, it all eyes looking west at the moment regarding the development of that low pressure system.

[SnowObsessor90]

Whenever the 18z's in a sober mood it generally doesn't fill me with much confidence about the 00z's to follow and with good reason. Hopefully those fears don't end being realised come the morning.

Edited November 13, 2012 by Anonymous21