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

[blizzard81]

The biggest trend today has been the introduction of a possible Scandi High at the end of the coming week. ECM has been toying

with this over the last couple of days and I believe the GFS is now entertaining the idea of this. I believe the possibilty of a Scandi

High is coming about as a result of some very cold uppers in Scandinavia over the next few days and the models will not get to grips with

this until much nearer the time. Put it this way, I would not be suprised to see the 00z models showing a rebust Scandi High by the

end of this coming week thus advecting some very cold air our way. This also ties in with Chio's posts with regards to Cohen re Strat warming.

Edited December 16, 2012 by blizzard81

[OldMetMan]

Major shift in the surface pattern between 12Z and 18Z with the GFS, and that is before T180. That in itself suggests a high degree of uncertainty. Plus a NE moving LP as depicted earlier in this run is not something you would expect to deepen and rush E as shown. As I have said before, not a logical development!

[Kentish Snowman in Yorks]

Just look at that WARM plume advect north and smashing into the cold northeasterly, just a few hundred miles away from Snowmageddon

Yep. There cannot be more than 500/600 miles between the +10 and -10 uppers on that chart. It's gonna be a tough one to call although the way this winter has panned out so far you would have to favour a milder outcome at present. As ever more runs needed....

[bluearmy]

the block does a superb job of hanging on with help from the iberian ridge but once the low heights begin to sink south to our north, the game seems to be up for it. i just wonder if there is any chance if the atlantic becomes any weaker that the iberian ridge could get much further north ?

the solution before the block retreats east is going to be troublesome to say the least for forecasters.

[Zakos]

I think we can all agree that the setup is very complicated and uncertainty is very high.

all GFS runs today, for the same timeframe (currently 120 hours)

Every run sees:

>Atlantic further west

>Russian high stronger and further west

> Heights to our south lower

> stronger heights over Greenland

The positive trends continue, still not good enough yet though. I would strongly advise against looking too much into anything beyond 96 hours.

[Matty M]

The longer term outlook though isn't looking great and in the last few runs the Strat warming has been watered down a touch.

[blizzard81]

120 hr fax chart is great, no sign of azores high.

[Weathizard]

Whats going on here then? Thats one messy fax.

[TEITS]

Whilst Xmas is still looking uncertain im becoming more confident of the period between the 19th - 23rd.

A band of rain moving E during Wed will turn to snow across parts of Scotland especially the E/NE. This risk may even extend into NE England. During Saturday 22nd a band of rain will move E but this will turn to snow across E areas especially N England/Scotland and maybe even further S. However this will only be transitional snowfall before turning to rain as milder air moves in from the SW.

This forecast is very different to the Met O and is still subject to change. However based on all of todays output this in my opinion is the most likely outlook at the moment.

[chris55]

If the Low out in the Atlantic was angled with the WAA more south to north then we wouldn't be far away from some major building of the Scandi ridge! And with the Barents sea Low ready to move down the eastern side, it could be all in!!

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

A little far fetched I know and no support for such a scenario, but not entirely out of the question given the uncertainties at this time frame!

Edited December 16, 2012 by chris55

[blizzard81]

Whats going on here then? Thats one messy fax.

Going to save that as the 120hr faxes can be completely way off the mark. I hope this one is correct as it looks good from a coldies perspective.

[snowblues]

How long has it been with this high to the east.It must be a week now,time after time, the low is going to push through and surprise, surprise it is held back.looks like its here for awhile yet.It seems like some of the p/v is always being pushed over N Russia holding in place, just a basic look at the N/H.

Edited December 16, 2012 by snowblues

[bluearmy]

The longer term outlook though isn't looking great and in the last few runs the Strat warming has been watered down a touch.

not a problem, given some of the temp levels that were being touted. Reassuring to see that strat forecasts also become a little tempered as they tick down towards verification.

[Matty M]

One or two 18z GFS EPS members may ruffle a few feathers @ just T96hrs

[Matty M]

The upcoming synoptic is extremely messy and quite strange.

Is there any analogue to this in the historic charts?

[Weathizard]

One or two 18z GFS EPS members may ruffle a few feathers @ just T96hrs

Shows you just the uncertainty thats around at the moment that we can have ENS at 96hours that are VERY different to one an other, a very difficult and complex scenario in which I'd imagine the forecasters are going to have a nightmare!

[blizzard81]

I think everyone is mentally exhausted after the last three weeks but the 18z ensembles certainly raise a few eyebrows at very short notice!!

[Backtrack]

Excuse me whilst I go and throw up.

The 12C 850 line approaching our shores in Mid-December? That's just...

Why can't we have that in summer!?!

God damn Azores High.

Edited December 16, 2012 by Backtrack

[damianslaw]

Last post from me this evening on what has been a day of model watching headache, with so many chops and changes in the 96-120hr timeframe, this is a very uncertain time indeed. However, as we end the day the common emerging themes for next week -

a- the russian high is not going to go away anytime fast and if anything is likely to exert greater influence on our weather than first thought.

b - heights to the south are likely to be much weaker and therefore no longfetch southwesterly and consequently temps as a whole much nearer the norm, and slightly below in the south

c- the atlantic is not about to ramp into full normal winter mode, indeed it looks weak and the trough is likely to split with shortwave attacks.

Where does this leave us as we head towards christmas - scratching our heads!!!

[chris55]

GEFS wide open at 120. We have everything from North easterlies to dart board lows to mild southwesterlies.

[bradymk]

Some encouraging 18z ensemble members for coldies. This is going to be one tricky week for forecasters. Personally hoping for more positives tomorrow from a cold pov. The models are so inconsistent at the moment which is just resulting in not having a clue what the actual output will be several days down the line. ECM op was a mild outlier xmas period with the EPS bringing colder weather in after xmas day but cool rather than cold but this is a developing evolution and between Xmas and new year looks more promising for cold. Model watching just isnt quieting down at the moment and we have the promising January to come yet!!

Edited December 16, 2012 by bradythemole

[Eskimo]

d

The only vague similarity I can see is 1962

Edited December 16, 2012 by PerfectStorm

[Panayiotis]

Whats going on here then? Thats one messy fax.

300 miles south=fun and games for all!

One or two 18z GFS EPS members may ruffle a few feathers @ just T96hrs

Spontaneous easterly anyone? People on here say easterlies just come out of nowhere! Edited December 16, 2012 by panayiotis

[Captain Shortwave]

I think we need to wait for the 00z to come out before saying anything more here. The pub run might have gone mad tonight. But if there is a continued westwards trend we might see things being modelled very differently, so whilst the runs still point to an unsettled and average if complicated set up, there is the chance (if only slight) that the models might flip tomorrow with a possible Scandinavian high building as the low to the north of Norway starts having a real effect on the Russian high.

To be honest the northerly over Christmas is out of the window now, i find some of the charts, posted on the previous page amazing, there is literally a few hundred miles between some very high temperatures for this time of year and us being put into the freezer. Absolutely fascinating.

[LomondSnowstorm]

I think we need to wait for the 00z to come out before saying anything more here. The pub run might have gone mad tonight. But if there is a continued westwards trend we might see things being modelled very differently, so whilst the runs still point to an unsettled and average if complicated set up, there is the chance (if only slight) that the models might flip tomorrow with a possible Scandinavian high building as the low to the north of Norway starts having a real effect on the Russian high.

To be honest the northerly over Christmas is out of the window now, i find some of the charts, posted on the previous page amazing, there is literally a few hundred miles between some very high temperatures for this time of year and us being put into the freezer. Absolutely fascinating.

Just to complicate the issue further, it isn't:

I've found the last month to be perhaps the most interesting spell of model watching I've ever experienced, with almost permanent interest but with so much uncertainty too.