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

[Buriedundersnow]

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.

we can still get a northerly from here if we are left with a scandi high there every possibility that it will then retrogress to greenland

[Severe Siberian icy blast]

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

Agree it fits in perfectly with the climatology analysis you gave the other day, if it corrects south anymore Ed we would be looking at a nationwide cold spell , agreed??

[Buriedundersnow]

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.

the gfs has been consistant up till the 22nd thats where the key was and reall FI started its the attempted undercut that decided where we went wether the undercut comes off or not past then theres a few ways we can go

[The Eagle]

UKMO 96hrs

GFS 96hrs

[Matty M]

Of course i'd expect to see an inversion from a cold continent but an inversion to that extent seems a tad crazy.

Love to see a tephigram for say Brugges!

[MrSunshine]

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.

Why are you getting annoyed, possibly because its showing a cold scenario maybe?

[Mark Bayley]

And a much better run stratospherically as well! Certainly the vortex is going to come under great attack as we enter January

Edited December 18, 2012 by Mark Bayley

[Cheese Rice]

The GFS isn't a big shift by any means it merely extends the influence of the Siberian high towards the UK. This should be expected and is a precursor of future outputs where the high will meander west or east. The output is unlikely to verify in its current projection although the general theme is correct.

Potential for short sharp easterly outbreaks and undercutting lows along with heavy frontal snowfall. North east looks the most favourable currently where colder weather is most likely, further south is a lot less clear cut.

Edited December 18, 2012 by Cheese Rice

[karlos1983]

Good old GFS, 597 users online.

My hopes are not going to get up to much on one run, but I will eat my hat, gloves, scarf and sledge if this verifies.

[Winter Monsoon]

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.

At this present moment in time yes.

And again another change on the GFS putting it at odds with UKMO so which one is right??

[davacr123]

Good old GFS, 597 users online.

My hopes are not going to get up to much on one run, but I will eat my hat, gloves, scarf and sledge if this verifies.

Do you want sauce with that sir lol

[Dampdorset82]

Exactly, the pattern change over the Xmas period has changed alot. The upgrades for the reliable are good the AH is moving south as you say to allow the low pressure to move east. I wouldnt be suprised by the time the 18z roles out there will be a few suprises for Xmas day!

the GFS 12Z has done exactly what I thought expect the 18z to be along the lines of ecmwf.

[Buriedundersnow]

the UKMO isnt that different from the GFS there both similar at 96h and is that not where UKMO FI starts

[Chess01]

The gfs has had this trend for the past week with 1 or 2 runs dropping it i have no evidence but i just think this cold spell will happen because this will be our 3 pop of the cherry and just think it will happen and it will be all in time for xmas

[chionomaniac]

Agree it fits in perfectly with the climatology analysis you gave the other day, if it corrects south anymore Ed we would be looking at a nationwide cold spell , agreed??

One of the reasons that I said watch and wait on the strat thread is because I didn't expect to see an evolution like this so soon.

And I still find it too soon, because of the wavering of the strat warming forecasts - one would have reasonably expected to see a SSW at the end of FI in the strat. But we haven't yet (haven't looked at the GFS 12Z though). So I set a date of a possible SSW of around 10th Jan - but this date is a moveable feast or possibly none existant at all. So strat warming, yes, SSW perhaps.

Oh and to TEITS I thought that you meant a cold spell before Christmas over the whole UK but realise that you are talking more before Boxing day. I think before New Year is a possibility but wouldn't go anywhere as high as 50% before Boxing day ( even after the 12Z GFS run)

I will guess that two of the GFS ensembles will follow the 12Z GFS operational. Any more than five and I may just prick my ears up!

[Panayiotis]

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

What was that we are going to have a mild Christmas (not directed to you No balls like snow balls)? lol However as a coldie, this is what you would expect me to say, still seven days for all to change, for better or for worse! Edited December 18, 2012 by Panayiotis

[Zenarcher]

While the UKMO isn't as great as the GFS it does move in the Russian high more West than what it did yesterday,

Quickly made the above image it shows yesterday and today's 12z runs of the GFS and UKMO side by side notice how the GFS remains fairly consistent where it places the Russian high and how far West it goes. The UKMO underdone the Russian high yesterday and today as shown it's had a big upgrade and similar to what the GFS showed yesterday and even today.

Edited December 18, 2012 by weathermaster

[Matty M]

There are solutions in there on the 12z GFS EPS of potential easterly.

Definitely a different slant to the EPS this evening, than a few nights ago.

The whole modelling of the Azores High and Russian HP incursion has changed dramatically.

Edited December 18, 2012 by Matty M

[Coast]

I can see colder happing in parts from Boxing Day onwards, if GFS free-atmosphere is on the right track. But the 500-1000 hgt line doesn't quite get there currently in the South, but interesting in the North:

[Nick F]

I think differences which develop between 12z UKMO and GFS post T+96 lie down to the greater WAA aloft on 12z GFS ahead of the deeper low out in the Atlantic - which reinforces the block over Scandinavia - which in turn prevent the low getting as far east. So we have a cold SE flow on GFS op rather than the mild southwesterlies of the UKMO.

Jury's out for me until I see the ECM, as it's been GFS vs Euros so far with regards to how much the Atlantic makes inroads.

[The Eagle]

Some ensemble support for building a scandinavian high by 144hrs. Most have it orientated awkwardly though.

[Snowmad79]

How the hell does the GFS work out the PPN charts? A couple of days ago the upcoming weekend looked like a quick blast of wintery ppn amongst a deluge of rain for my area (West Pennine) and the NW in general. This latest GFS run gives me an absolute pasting of white stuff from Saturday through Monday but when you look at the uppers, thicknesses and dewpoints etc it looks way off.

I mean seriously, this run moves the run-up-to-xmas snow (not including Scotland) from eastern fringes to the WEST and NORTHWEST. Not that I'm buying into it mind!

I'd be over the moon if this came off despite all the crap the models have thrown at us lately and it would make Atlantic weather all the more bearable too

[Paul White.]

UKMO is poor http://www.meteociel.fr/ukmo/runs/2012121812/UN120-21.GIF?18-17!! I believe we should be done with this pattern and move onto the next one folks

What do you mean about move on from this pattern. It's not like we have a choice and control what the NWP produce. If that was the case then I would put a scandi Greenland block in place for the next three months

Paul

[124alex]

How the hell does the GFS work out the PPN charts? A couple of days ago the upcoming weekend looked like a quick blast of wintery ppn amongst a deluge of rain for my area (West Pennine) and the NW in general. This latest GFS run gives me an absolute pasting of white stuff from Saturday through Monday but when you look at the uppers, thicknesses and dewpoints etc it looks way off.

I mean seriously, this run moves the run-up-to-xmas snow (not including Scotland) from eastern fringes to the WEST and NORTHWEST. Not that I'm buying into it mind!

I'd be over the moon if this came off despite all the crap the models have thrown at us lately and it would make Atlantic weather all the more bearable too

what is the link to this chart please?

[Snowmad79]

what is the link to this chart please?

It's on the Meteociel model options here: http://www.meteociel...6&code=0&mode=2

Xmas day

Edited December 18, 2012 by Snowmad79