Winter Model Discussion - Cold Hunting -12Z 30/12/12

[mulzy]

18z may be NH synoptically interesting in FI but as far as the UK is concerned it's another diabolical run - the 528 dam line remains well to the north for most of the run. The key to me is the heights to the south of us - somehow pressure needs to fall in continental Europe.

Edited January 2, 2013 by mulzy

[Brass_Monkeys]

There is talk of a 3rd strat warming on twitter from Weather Tweets??!!

I hope it's ok to insert this link in the model thread. Quite an interesting read regarding the SSW and does mention a possible third warming event.

http://theweathercentre.blogspot.co.uk/2013/01/multiple-stratospheric-warmings-confirm.html

[Bobby]

The 18z just follows the consistent trend showing in the ensembles and the NAEFS to send a piece of PV our way from the NW in mid-Jan turning things very unsettled.

12z NAEFS is much the same as the 00z, as it was yesterday

When looking into FI I don't see much point looking at indivudual op runs, much better to use the ensemble means, NAEFS anomaly maps etc as they're more stable.

Upper temp anomalies:

The GEM pressure ensemble mean is in general agreement also with the GEFS/NAEFS, +300

Upper air mean

So there is consistency, the OP runs will always swing widly in FI. Always have always will do.

Just trying to add a bit of balance.

Of course it's a long way out and could change etc.

Edited January 2, 2013 by Bobby

[ITSY]

I hope it's ok to insert this link in the model thread. Quite an interesting read regarding the SSW and does mention a possible third warming event.

http://theweathercen...gs-confirm.html

Very informative and helpful. If that verifies and high pressure does indeed come to dominate the arctic, with the suggested 3.5+ degree anomaly over Greenland (see the end graphics) then we would be unlucky not to see a cold outbreak. He, and given his knowledge I trust his outlook, is talking about post Jan 20th for cold for the US. Don't get hung up about current outputs then and be prepared for colder ones come the weeks end. (that is not to be taken as gospel or as indicating that cold WILL come, merely that it could).

Take a look at recent tweets from Chris Fawkes (BBC weather and cold lover):

Chris Fawkes â€@_chrisfawkes

Incidentally, sudden stratospheric warming spliting the vortex can exert an easterly influence on the troposphere for 2 months. Cold winter?

Chris Fawkes â€@_chrisfawkes

@GavinPartridge we'll see! The ec 12z run puts an omega upper pattern w of Norway. If that happened that would build high over Scandinavia

Edited January 2, 2013 by ITSY

[Jason M]

Ensembles are trending to northern blocking at 180 hours. Really noticeable increase in the number going for this. Some are going quite early as well. Good old GEM might be showing the way.

Jason

By 192 there are several corners and a number of others look like given time...............

Edited January 2, 2013 by Jason M

[Tom Montalbano]

Quote

Chris Fawkes @_chrisfawkes

@GavinPartridge we'll see! The ec 12z run puts an omega upper pattern w of Norway. If that happened that would build high over Scandinavia

Hi sk,

Thats a very interesting comment from Chris Fawkes re. that omega pattern trying to form over Norway.

http://www.wetterzen...cs/Recm2401.gif

At face value looks quite a weak affair but it could well go on to form something much stronger.

Yes, I'm someone else dusting down an archive chart from Dec.1962 but would you have said this high forming over Scandinavia would go on to become such a strong feature a few days later.

http://www.wetterzen...00119621220.gif

http://www.wetterzen...00119621224.gif

I know, cherry-picking archive charts but interesting nonetheless!

Regards,

Tom.

Edited January 2, 2013 by TomSE20

[EML Network]

I think it's a little too early to be writing off the rest of the Winter just yet, if by the time we get to the 20th January and the outlook remains the same as it does currently, then I have to confess, we will be starting to run out of time.

I think there's a lot of frustration due to the models really not wanting to do anything with that pesky High Pressure system that just seems to want to spend a good week visiting the in laws in France.

To be fair the models have been very consistent with keeping that High over France for quite some time now, we always knew before the end of 2012 that we were going to have to endure a quiet spell, with not much going on...but there's a well known saying..."The Clam before the Storm" ...let's hope this is pertinent for us and equates to cold and snow headed toward our shores as we go through the month.

[Bonjangle]

So most peeps are writing of winter in here (Gulp) very foolish indeed i must say , its is only the 2nd of january for goodness sakes , pull yourselves together like a pair of curtains !!!

So why are Meto not really writing this of but getting very exited instead , what can they see what we cant , anyone know ?

Just loving some of the bullish posts that make us newbies trying to learn something , go all down the pan and give up .

Winters ready to sting you all that think its over , Rant done .

[phil nw.]

It`s all about trends and looking at the 12zECM means and ht. anomalies we can see slowly but surely the Atlantic zonality is in it`s current end game as pressure rises across the UK in the next few days.

Compare the mean pattern at T96 and T240

Clearly the low heights across the pole are warming and the troublesome Greenland energy on the retreat towards Canada.

Notice the ridging in the flow to our north starting to exploit the weakness between the 2 main pieces of vortex.

This follows on from the 00z run with this tendency to continue that ridging further north into week 2 .

The Mean Ht anomls.

We are not there yet but this data shows things gradually changing to a more -AO and -NAO setup from around mid-month..

[TEITS]

Just trying to add a bit of balance.

Of course it's a long way out and could change etc.

Very little consistency and using ensemble means is a waste of time at the moment. I haven't looked at the 18Z but when I looked at the 12Z GEFS ensembles they were useless because they were showing a wide variety of outcomes. When this happens the ensemble mean isn't representative of any of the ensemble members so the mean is skewed by this disagreement.

As an example, and i've only looked at the first few members but look at these below.

Now suppose 50% of the ensembles were like Member No 2 and the other 50% like member No 3. Do you think the ensemble mean would be any use? No is the answer and wouldn't look anything like those above.

[reef]

A quick reminder that there are several other threads where previous winters can be discussed, as well as the Model Mayhem thread where you can discuss whether you think winter is over or not to your heart's content. This thread on the other hand is to discuss the models.

Please try to keep this thread on topic.

Thanks.

[Weathizard]

One thing I think we can be sure of is that if we do get something cold, there will be copious amounts of snow with that lobe dropping into Europe.

PTB 2 or 3 is pretty special, ens are still pretty good actually. Think the general split in the ENS shows how much difficulty the models are having with the SSW reperecussions

Edited January 2, 2013 by Weathizard

[BLAST FROM THE PAST]

Well the difference between the 18Z and 12Z is laughable especially from +240 onwards. This is why at the moment its pointless to be disappointed or elated with the model output because they are simply clueless what is going to happen from mid month. We often see disagreement from the models beyond +240 but this level of uncertainty is increased in my opinion due to what is occurring in the Stratosphere.

The ECM tonight is very poor but based on recent output im not worried due to its poor consistency.

Dave

I think we should start taking notice. I think ECM and GFS are now showing signs of what i think will be stark change. dats of interest 8-10 [cold block to start showing to north?] and 16-22 [block in place atlantic push?] cold to win and a notable winter event

BFTP

Edited January 3, 2013 by BLAST FROM THE PAST

[LomondSnowstorm]

Very little consistency and using ensemble means is a waste of time at the moment. I haven't looked at the 18Z but when I looked at the 12Z GEFS ensembles they were useless because they were showing a wide variety of outcomes. When this happens the ensemble mean isn't representative of any of the ensemble members so the mean is skewed by this disagreement.

As an example, and i've only looked at the first few members but look at these below.

http://modeles.meteo...-3-1-276.png?18

http://modeles.meteo...-2-1-276.png?18

Now suppose 50% of the ensembles were like Member No 2 and the other 50% like member No 3. Do you think the ensemble mean would be any use? No is the answer and wouldn't look anything like those above.

Only thing I could discern from the ensemble means is that they're gradually, run by run, becoming that bit more amplified with slightly higher heights from the UK northwards and lower ones to the southeast, indicating an increase in more blocked runs. Any specifics past day 6 aren't really worth taking too literally at present.

The South Greenland anomaly is especially useless given that some runs clearly have a chunk of the PV with very intense cyclogenesis occuring while others have height rises building in.

Edited January 2, 2013 by LomondSnowstorm

[TEITS]

Last post from me for tonight.

The number of ensembles dropping below -10C is increasing.

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=306&ext=1&y=141&run=18&ville=Londres&runpara=0

[Cloud 10]

Yes indeed,plenty of eye candy to be found in the 18z ensembles.

Always nice to see the H!

[-uksnow-]

http://modeles.meteociel.fr/modeles/gens/graphe_ens3.php?x=299&ext=1&y=124&run=18&runpara=0

Large majority go sub 0 from 12th onwards, also i count around 5 sub -10 runs?

All very good building blocks if you ask me. Which many of you dont... ahah.

[LomondSnowstorm]

Yes indeed,plenty of eye candy to be found in the 18z ensembles.

Always nice to see the H!

I think Steve would agree that that most certainly is a ridge!

[bradymk]

Last post from me for tonight.

The number of ensembles dropping below -10C is increasing.

http://modeles.meteo...ndres&runpara=0

Yes was just about to post this, although there are still a variety of outcomes within the GEFS ensembles and still a few mobile runs, there has definitely been an increase in "very" cold members in the 18z suite and I am also sure that the cold is showing at an earlier timeframe than it was yesterday and the mean is now a couple of degrees below 0c at 850 from day 7 to 15. Eagerly awaiting the news from Ian.

[keithlucky]

Subtly hints that a change taking place of met outlook showed Atlantic charts with cold front pushing through Sunday with colder air behind latest fax charts hints at HP building from the North West.

[Panayiotis]

Ensembles trending in the right direction, which is obviously down! (not for all though)

Things I have noticed throughout today's ensembles is that members going for -8C to -10C uppers has increased on every run, with the 18z showing the most going for this cold.

Also seen by the ensembles is the Gfs maybe an outlier, just look at the precipitation predicted, with the GFS at times showing more rain than all of the other members, look at the 12th for example.

Oopsy just seen the above posts

Edited January 3, 2013 by Panayiotis

[ITSY]

very encouraging ens IMO, with 9 or 10 creating some very nice scenarios blocking wise. another step in the right direction IMO, albeit without the op and control in tonight's group.

[Iceaxecrampon]

Grim

Dark Dank and Drizzly in Durham?

Ian

[Weathizard]

One of those rare occasions where the ENS for my location are actually better than Aberdeen! Still a long way from being nailed though, lots and lots of scatter but trending a lot colder and a lot better to my eyes. Hope to see more improvements in the morning.

[Mark Neal.]

Interesting to see more cold weather solutions in the models. Over the coming weeks it is going to be fascinating watching how they show the changes and keeping a close eye on the Stratospheric Warming, it is going to be far from boring for any avid weather watcher. I got to feeling it is going to be a slow progress to any cold over the coming weeks, but then it will pick up and before we know it shall arrive on our shores, that is a hunch btw. A very special winter event is beginning to brew :-) Enjoy the ride!