Winter Model Discussion - The Hunt For Cold -12z 14/12/12

[No Balls Like Snow Balls]

On the GFS 12Z it looks like a East / West split in relation to the surface temps. the far South and SW get the mild double figure temps while further East remain in single figures. Still no clue what is going to happen but IMO we won't see no Easterly from this.

[LomondSnowstorm]

On the GFS 12Z it looks like a East / West split in relation to the surface temps. the far South and SW get the mild double figure temps while further East remain in single figures. Still no clue what is going to happen but IMO we won't see no Easterly from this.

Depends who you mean by 'we':

[Jason T]

I can't take any model output seriously at this moment in time, all of them have been truly woeful over the last few weeks with huge differences starting at +72 on most days of model viewing. In the last thirty years we really have got nowhere in modelling HP to our East.

Could it be the case that there is a bigger pattern change going on behind the scene's that is really causing allround problems with the model's.

[OldMetMan]

Starting to make more sense the way this is going synoptically speaking as we suggested last night.

I never did buy the idea of extremely mild SW,lys via the LP moving N. What we are now seeing is this LP taking a more E,ly track rather than a N,ly. The outlook for xmas could become very different over the next few days.

Yes indeed TEITS, more logical. More so would be for the more northerly placed LP to get absorbed into the developing wave running E, but a much more W-E jet orientation. It seems the GFS at least is now taking more account of the strength of the cold air blocking - well for the moment anyway!

By the look of the remainder of the run, the GFS has again gone bonkers so I will have no hesitation in ignoring it!

Edited December 17, 2012 by OldMetMan

[No Balls Like Snow Balls]

Depends who you mean by 'we':

By we I mean the majority of the UK :-)

[Paul T]

Todays 12z is very similar to yesterdays 12z (see below for MO, which was very similar to GFS) only for the models to 'downgrade' the chances of cold on the 18z, 00z, and 06z.

A similar forecast or even an improvement on the 18z's output would be hugely important.

Edited December 17, 2012 by Paul T

[lorenzo]

Ignition sequence start T+156 Hrs, time for that nuisance block to show it's real worth.

One decent ridge and vortex goes boom.

[LomondSnowstorm]

By we I mean the majority of the UK :-)

Well UKMO has an easterly (well more like ENE) flow as far south as about Suffolk. You're probably right though in the sense that it's unlikely to be all that cold uppers wise away from the northeast

[Mark Bayley]

Ignition sequence start T+156 Hrs, time for that nuisance block to show it's real worth.

One decent ridge and vortex goes boom.

And a stronger warming than some previous runs as well.

Plus we can throw some wave breaking into the mix

Something tells me the PV isn't going to fair well as we enter January..!

Edited December 17, 2012 by Mark Bayley

[BOMBHEADS]

there seems to be a trend on each GFS run for pushing the russian block further and further West, I know this is getting nearer to the reliable time frame, but is there any likely hood it will continue to push further west??? we could end up with a nice little battle ground over the UK, with ok the atlantic winning out.

[TEITS]

GEM is just as mad as the rest of them if you compare the 12Z to the 0Z.

Cold E,lys in N Scotland.

http://modeles.meteo...em-0-138.png?12

SSE,ly on the 0Z!

http://modeles.meteo...em-0-144.png?00

This is like back in the old days when forecasting out to 5 days was impossible.

Edited December 17, 2012 by THE EYE IN THE SKY

[Stationary Front]

The westward movent of the block was something Chiono was talking about in the strat thread

[Summer Sun]

Im sure the members in Scotland are loving this run.

http://www.wetterzen...s/Rtavn1201.png

It wouldn't be bad for northern England either

GP has just posted an updated in the Strat thread as well -

Edited December 17, 2012 by Gavin.

[Isolated Frost]

For me it seems the window the opportunity for snow shrs in N/NE Scotland and parts of the Borders is Thursday onwards, with the UKMO and ECM earlier op signal indicating the highest probability around Friday evening/Saturday- especially across the N Isles and NE Scotland. The modelling of the main shortwave feature- which is attached to the trough due west is interchangeable and it's current position according to the UKMO op would provide snow shrs through much of Scotland, especially the east on Saturday- with the chance of snow shrs on Cheviots and North Pennines above 150m. The likelyhood of rain is also quite strong across many southern and midland areas- along with N Ireland and Wales towards the latter stages of the week.

All in all, the 12z output has strengthened the likelyhood of snow shrs from the E/SE above an elongated shortwave on Friday, Saturday and potentially Sunday for parts of Scotland and northern England. The main source of precip will be convective in more northern parts, this associated with snow, whilst other precip will be more frontal and more likely to be less wintry.

As with more zonal outbreaks, the upcoming 7 days look like being cool, colder than average for much of Scotland and at times northern England, whilst being more average elsewhere. The best chance of any milder weather will be across the south and west- and with the Iberian +ve heights after D4 (in line with Cohen ssw composites but shhh), and a weak mean trough stable to the west and south-west, it looks distinctly average for the time being, the signs of change are nearby and they don't favour rampant zonality and widespread mild weather...

Appreciate the upcoming synoptics, it's all weather!

[peterf]

It wouldn't be bad for northern England either

GP has just posted an updated in the Strat thread as well - http://forum.netweat...20#entry2450032

well happy with that.

[Panayiotis]

In this run we can see the Arctic high (the one ive been talking about for a couple of days now) has increased in size and is stronger than in the 12z, this makes the difference as it migrates to the center of the pole, which helps weaken the PV. It nearly splits the PV, but its location and strength is one to watch as it could help us in the longer term. Keeping my eye on it to see what it does in the 12z.

Edited December 17, 2012 by panayiotis

[snow1975]

Look at the 12z Gem at 144h

[Tom Jarvis]

well happy with that.

Not good for us southerners I could bet you when the dust settles the m4 corridor will be the difference to rain and snow lol

[Severe Siberian icy blast]

Quite a significant shif in the models tonight, seems to have really strengthened the high to our east aswell as developing high pressure toward Greenland , another shift south And we will be looking at country wide cold spell again, and to be honest I wouldn't be at all supprised given the snow cover and deep cold over Europe , with big things taking place in the strat , the vortex is out on a limb and its days are numbered it seems, there's been a lot of despondency on hear recently , but with things as they are the future really is bright over the winter months with a favourable strat that leaves the wide open to northern blocking.

So although the models churn muck out sometimes it doesn't mean it will turn out like that as , I feel we're about to find out , the models took that last cold spell away from us from under our noses, but we may get it back as the warm spell is already goin up our noses !!! Interesting times, we may see upgrades now as the models begin to deal with the reall the reall force. . . The Russian/scandi high!!

Edited December 17, 2012 by Severe Siberian icy blast

[peterf]

Not good for us southerners I could bet you when the dust settles the m4 corridor will be the difference to rain and snow lol

plenty time for more change yet.

[Weathizard]

Not good for us southerners I could bet you when the dust settles the m4 corridor will be the difference to rain and snow lol

A safe bet, that's normally the way to be fair! Not looking good for some down here, aside from the cold discussions the rain totals projected for the next week are not good at all. I'm more worried about that than the possibility of snow because I think we can write that off in the far south really. (From an IMBY pov)

Edited December 17, 2012 by Weathizard

[Buriedundersnow]

just got in and seen the 12z and its good to see we are still seeing small upgrades.

my ideal way i would like to see things is to keep seeing upgrades and get the undercut then to be left with some sort of scandanavian high then for that to retrogress to greenland just when the strat warming is kicking into full gear and staying there throughout january and into february.

very much doubt it will work like that but we can all have dreams lol.

[Panayiotis]

just got in and seen the 12z and its good to see we are still seeing small upgrades.

my ideal way i would like to see things is to keep seeing upgrades and get the undercut then to be left with some sort of scandanavian high then for that to retrogress to greenland just when the strat warming is kicking into full gear and staying there throughout january and into february.

very much doubt it will work like that but we can all have dreams lol.

Probably not as this is what we are all hoping will happen, but as you know we never get what we want However upgrades might be a possibility, hopefully ecm and 18z show this! Edited December 17, 2012 by panayiotis

[Frosty.]

The latest models are teasing that areas away from the main risk zone (n/ne scotland) will join in with a risk of snow, we need more runs to firm up on this before it means anything but at least it strengthens the risk of an undercut for the main risk area later this week and through the weekend with cold 850's pushing west, looking forward to the ecm 12z to see if it matches or improves on the 00z which was already pretty cold for the far north of the uk. It's a shame that most of the uk still looks like missing out on the undercut, it's finely balanced even for the far north and northeast but we should know for sure in the next day or so.

Edited December 17, 2012 by Frosty039

[BLAST FROM THE PAST]

Not good for us southerners I could bet you when the dust settles the m4 corridor will be the difference to rain and snow lol

But at the moment, is that right? We are seeing as model swing going on today. Is it a red herring? Or are we seeing the beginnings of a new shift. It is very possible as the models are proving that they cannot be trusted at present.

BFTP

Edited December 17, 2012 by BLAST FROM THE PAST