Model Output Discussion

[kumquat]

December the 13th is the operational's annual leave. He gets to see santa in the ice cave, leaving mum and dad in the local tapas bar.

[nick sussex]

Yeah a step back from an easterly today Nick.

As soon as the shortwaves appeared it was game up for an early shot of cold and those heights over the pole programed for T144hrs on have diminshed.

There`s just too much energy coming off the Canadian vortex to our NW compared to yesterday`s runs.

I think it`s odds on we are now looking at a midlatitude high nearby for a weeks time with some cooler surface temps but any real cold will stay East for now.

Things can change later on though and if the vortex remains fragmented there is always another chance when the jet allows.

Yes Phil its the same old story, although the ensembles aren't quite as bad as i expected, shortwaves seem to always appear as soon as any easterly is progged in the later output. I wonder whats in store tomorrow, maybe they've overreacted to upstream events and we'll see another twist in the latest model drama.

[kold weather]

The shortwave is a big problem in the medium term however if it can cut off from the vortex itself then it could actually become an ally as it could be shuffed southwards forcing the high to take the next step northwards.

I also suspect the GFS is a little too much to the east this run with the intial high BUT that has been a trend these last few weeks to shift everything east so its one that could have real substance as well.

Finally, I actually think the 18z is a fine run, sure it takes 2 bites of the cherry and its not a full blown monster cold run but the building blocks are clearly there.

[Duane S.]

Reference the ensembles. Firstly, wow, never quite seen an outlier like the Athens one posted above and secondly, I am very encouraged by tonight's ensembles for my neck of the woods after looking at the GFS (18z). Nothing spectacular and the operational wasn't what I would class as an outlier but there are more members looking to go cold and VERY cold to boot. I await the next few days with baited breath, but - my gut tells me we are looking at a HP cell sat smack over us with Europe getting the brunt of the cold, however, IMO, our big chance comes a few days later.

[kold weather]

I wouldn't be all that surprised if thats the case s4lancia.

Something that as I said in my previous post that could wind up being very interesting is the fact that the shortwave could wind up being useful, I've seen probably at least 3-4 ensemble members that give us cold conditions through the shortwave closing itself off and getting further east before dropping down into Europe. Its not something I'd pay too much attention to right now but just remember it as it could play a role.

[SMU]

I wouldn't be all that surprised if thats the case s4lancia.

Something that as I said in my previous post that could wind up being very interesting is the fact that the shortwave could wind up being useful, I've seen probably at least 3-4 ensemble members that give us cold conditions through the shortwave closing itself off and getting further east before dropping down into Europe. Its not something I'd pay too much attention to right now but just remember it as it could play a role.

this ^^^

Ive made a couple of attempts at saying this, though in a roundabout way its the combination of the -AO pressure belt & the second wave of atlantic ridging that would send the shortwave south / south east-

I would love to have seen the ECM 12z control run this eve....

Steve

[Eugene]

GFS 00Z looking much better than 18Z so far, nice ridging northwards and a nice shape to the high

http://www.wetterzentrale.de/pics/Rtavn1561.png

[yido]

In the reliable timeframe for me up to T168 a much better run, I think it was Steve who said we could do with things shunted 300 miles east, seems thats what we got

Edited December 6, 2009 by yido

[Eugene]

Yes and FI is much better too, look at that cold plunge into europe

http://www.wetterzentrale.de/pics/Rtavn2762.png

I love those lovely elongated highs

http://www.wetterzentrale.de/pics/Rtavn2761.png

[yido]

I so nearly thought that was going to turn into a very very good run with real heights builing over Greenland for a while. Still a big improvement so I'd say whatever the permitation in the end it should certainly be dry with the possibility still there of something much better.

[SMU]

this ^^^

Ive made a couple of attempts at saying this, though in a roundabout way its the combination of the -AO pressure belt & the second wave of atlantic ridging that would send the shortwave south / south east-

I would love to have seen the ECM 12z control run this eve....

Steve

those with a nervous disposition step away now......(p) adult content-

http://91.121.94.83/modeles/gfsp/run/gfsnh-0-240.png?0

S

[Cecil Hogmanay Melchett]

I stayed up to watch that and this is going to the wire.That energy spinning off the Icelandic low is absolutely

crucial.0Z shows what can happen if the high can get further North.This might not be resolved until Monday IMO.

The Euro's again crucial but gfs has pulled a rabbit out the hat with that run,is the game back on?

[yido]

I'm off to bed now as I'm in San Antonio Texas, but certainly something to keep up interest when people start waking up.

Just as a side point this place sums up why we really do struggle with cold weather. Average temps here in July and August over 100F. It snowed yesterday!

[Optimus Prime]

Yep a better run more of a south easterly flow so very dry with no frost but cold.

I'm off to bed now as I'm in San Antonio Texas, but certainly something to keep up interest when people start waking up.

Just as a side point this place sums up why we really do struggle with cold weather. Average temps here in July and August over 100F. It snowed yesterday!

You lucky laminate floor!

[SMU]

Yep a better run more of a south easterly flow so very dry with no frost but cold.

You lucky laminate floor!

http://www.wetterzentrale.de/pics/Rukm1441.gif

UKMET in....

not bad at all

Steve

[Iceberg]

My initial thoughts are that GFS has improved a bit, the alternative GFS is quite nice, but the ensembles are pretty dire still. GFS seems to be suggesting several cold attempts, as blocking to the north is much stronger.

Meto is following the ECM IMO.

ECM, so far looks rather quite good, the initial easterly has pretty much gone, but the HP is further north, despite the shortwave, now ECM boots the shortwave out of the picture pretty quickly allowing for further heights to build over Scndinavia pushing cold weather our way come the 14/15th.

Not seen the ECM 500 charts yet though.

So more evolutions but not neccesarily abandoning the potential cold.

[phil nw.]

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

UKMET in....

not bad at all

Steve

Following the better 00z runs from GFS and UKMO the ECM wants to join the Cold party

http://charts.netweather.tv/ecmimages/20091205/00/ecm500.168.png

Much better ridging into the Arctic on all 3 o/night.

[Duane S.]

I think all in all the 00z runs are very promising. METO looks to be heading in the right direction, which is a bit of a relief. The GFS is good again and the ECM very decent indeed.

The one downside for me is the GEFS ensembles which are not brilliant but at this stage I am not too concerned about this.

[Methuselah]

'Morning Ian...New day, new evolutions?? Wait and see, methinks?

[MR EXTREMES]

those with a nervous disposition step away now......(p) adult content-

http://91.121.94.83/...snh-0-240.png?0

S

oh please steve my my that is something special.

[nick sussex]

Morning all

A better start to the day with hopes of something colder rising again but a very long way to go, it looks like hopefully the models have started to settle down within the 144hrs timeframe, sometimes when they react to slight upstream changes they tend to over do this and its always best to give them a few runs.

In terms of the ensembles these still look half hearted but one thing i would note when dealing with crucial shortwaves is that the operationals should take centre stage upto 168hrs, the reason being that they will have a better handle on these because of the higher resolution, essentially with many easterlies you're dealing with fine margins between success and failure, often the UK is right at the end of the line and the major stumbling block isn't getting the cold source to tap into but getting this to back far enough westwards.

This still looks difficult this morning but at least we've seen a halt to the downgrades.

[Frosty.]

Nice to see we can still get charts like the one Steve posted in the even larger teapot although it's still very much a fantasy chart. After some hic-ups yesterday I don't think we are really any better or worse positioned than we were compared with the 00z runs yesterday. The atlantic is going to run out of energy later next week and we are going to have an Anticyclonic spell with probable cold but very dry air off an increasingly bitter continent but hoar frost is unlikely and neither is fog with the dryness of the airmass, I fully expect more set backs because everything has to click perfectly into place for the uk to get a cold spell, unlike mainland europe and the usa where it's much easier.

[cooling climate]

Very encouraging output again this morning, is this the start of a backtrack from the models

this morning? I think it is.

I think we will see a trend from the models to build much better heights to the north and

northeast as the Arctic high comes into play. (The Arctic high is the major player here).

The troublesome shortwaves modeled at the moment will become less of a issue or

disappear from the output altogether.

As GP has said because of the easterly momentum from the Arctic high we should see everything

back further west allowing for better heights to the north.

Here's to a very cold outlook.

Edited December 6, 2009 by cooling climate

[Iceberg]

Just a work of caution Below average temperatures for most people are still 6 days away (next Saturday), I fully agree that a cold spell is possible/ very likely, but is far from nailed yet.

[I remember Atlantic 252]

00z's horrid massive pressure outlier, coldish outlier, GEFS control mild all through, no cold ensembles, I wouldnt be surprised if the settled spell only lasted 3 days, and back to unsettled on 14th