Winter Model Discussion - The Hunt For Cold -18z 17/12/12

[Matty M]

I know inversions etc. But the 12z looks wrong.

Dewpoints versues 850hPa

[-uksnow-]

GFS wants a nice little white christmas for the south...

[Snowstorm1]

Runs the bookies! Aberdeen 7/4 suree....

[Frosty.]

Nope mate its pap!! http://www.meteociel...44-21.GIF?18-17!!!

Yes but it might be wrong

[Cheshire Freeze]

I know inversions etc. But the 12z looks wrong.

Dewpoints versues 850hPa

There's a SE'ly feed off a frigid continent. The continent can be well below 0 temperature wise at this time of year- even with highish 850's. The air is often drier aswell which lowers the dew points.

[Weathizard]

These charts are ridiculous at the moment, look at the difference between them. Serious uncertainty, nothing can be trusted in my eyes

[J10]

Despite the mild uppers, if we were to get a SE flow on Christmas Day, and until other models agree, I'd suggest GFS is off on one again. It would be very cold on the big day.

06Hz GFS ->

12Hz GFS ->

Edited December 18, 2012 by Jackone

[No Balls Like Snow Balls]

If the GFS12Z verifys I will eat more than my hat.

[EML Network]

How on earth can these 2 charts be for the same time on the same run ? this makes no sense

850 Uppers

Temperature

500 Temps

Anyone ???

[Buriedundersnow]

well isnt that what we all wanted to see a blocking high left over from the russian high and hopefully that will be the form horse from now on as that is the best solution from where we are right now and could kick start a colder period before the ssw kicks in and hopefully the gfs has picked up on a trend that others will come round to.

chio do u think this evolution is possible with the way the strat is.

[bluearmy]

similar to yesterdays gfs 12z op which hasnt really garnered support since. odd for it to resurface again 24 hours later..................................................

[Isolated Frost]

SE flow off the continent.. extremely cold temperatures across many areas, especially in the se of England for christmas day-

Don't expect the GFS op to be a mild outlier in comparison with the GEFS, the 850s will be similar but the airflow could well be markedly different.. on the operational however it is clear the Scandinavian/Baltic blocking high has beaten the Atlantic

[Winter Monsoon]

I'll call the GFS 12Z the Cohen climatology run!

Yup

[No Balls Like Snow Balls]

What a lovely cold christmas night it would be :-)

[Pixel]

GFS wants a nice little white christmas for the south...

is this an undercut? heard it mentioned here before but not seen one modelled..

someone?

[Ian Brown]

Well I was hoping to sort my YES/NO white Xmas bets out tonight, but I don't think I will be able to. This run sees the crucial 552 line appear from the Scandi High. Let's see what the ECM does.

[J10]

How on earth can these 2 charts be for the same time on the same run ? this makes no sense

850 Uppers

Temperature

500 Temps

Anyone ???

The feed form the surface would be very cold this time of year, there have been other occasions when uppers have been around +5c, and many parts of the UK have had ice days, if winds are from a very cold continent.

So synoptically this is plausible. (end January 2006 is a decent example. )

Edited December 18, 2012 by Jackone

[Zakos]

Struggling to see the logic in posts claiming to write off janurary, when the models cant even decide the weather 5 days away

Another huge shift to cold. Even with my optimism, I did not forsee such a big change.

If we can just get one more small shift west, we are in business, widespread snow across the entire country.

The UKMO does is not buying it though, illustrating the uncertainty.

A lot of people on here use keep referring to the ensembles. I think there is a common misconception that the ensembles illustrate all possible options, and the more runs that give support for a particular scenario then the more likely it is to occur. Im sorry but this is not the case. Especially in this setup.

Ensembles all follow the operational run, with different starting set-ups. If the GFS has massively underestimated the blocking signal (as it has done so recently), then all of the ensembles will do so aswell. I think the ensembles are useless right now, especially with their lower resolution

more changes to come i think, and I dont think it is hard to see how this could turn in to something special given a few changes.

[Buriedundersnow]

the charts arent that impossible the key part was always going to be the attempted undercut on the 22nd--23rd and this run is just showing how good things could turn out if little upgrades go our way it was always a fine line and anything was possible

[bradymk]

I give up, i want the russian high to run away to the east to help a northerly furher down the line but then runs like this come along. Well lets hope the GFS is a trend setter....if only, i highly doubt it but anything can happen with these models at the moment. If the ECM follows later i will put this down as the weirdest model watching period i have ever seen.

[-uksnow-]

Someones got sunglasses on in the Arctic...

[Craigers]

I know its FI but look what happens when the pressure lowers with that continental feed!

Under cut any one???!!!!

Edited December 18, 2012 by Craigers

[MR EXTREMES]

The set up from the gfs look completely wrong I'd bin the gfs its all over the place its not been consistent of late.

Expect no agreement with ukmo or the ecm grrr this is when I get annoyed with the gfs.

[UV-RAY]

Im sorry Where in my post did i say that??

Realisticly how can you take anything that any model is churning out post 144 and sooner? We have and probably will see changes, some minor and some major which go on in the grand scheme of things to have an impact upto and past +384(January)

And im sorry and i mean no disrespect by this but unless the meto have a crystal ball that allows them to see into the future, i fail to see how they can also reliably and accuratly predict whats going to happen after christmas day. As the models are varying so much.

I was commenting at how many hang onto every word by some who posts in here and I'm not just using the MetO as a reference. All the long range models paint a poor picture for cold, of course they all could be wrong but there must be some strong signal there and that is what I'm commenting on. Your crystall ball analogy could be used against any organisation or individual who makes a LRF, so we could discount anyone who forecasts beyond 10 days then.

[IDO]

If you follow the 1024 isobar of the Russian High it goes across the pole and is part of the HP that covers N.America:

http://cdn.nwstatic....168/npsh500.png

Is that possible? One huge HP covering most of the NH. Of course the knock on effect of this mega-high is amplification over the US so less energy for the Atlantic. Catch 22!

Edited December 18, 2012 by i'm dreaming of...