Winter Model Discussion - The Hunt For Cold - 10th Dec

[Paul]

We've made a small change to the format of the model threads this morning, with the main model discussion thread being renamed to the Winter model discussion 'Cold Hunt' thread, which will hopefully reflect the content of the discussion a bit more closely. There's of course nothing wrong with the fact many people are hunting for cold in the output, obviously many are cold weather fans, so why not have a thread dedicated to it, and stop the arguments about balance etc etc!

These are the current main model threads - but we are always open to suggestion in terms of other options:

The winter / cold model output discussion thread (this one) - busy, fast moving, sometimes a bit of a rollercoaster, generally cold orientated, with views from a wide range of people with differing interests, biases and levels of knowledge.

Model summaries and analysis - slower moving, more straight down the line type model assessments, info and discussion:

http://forum.netweather.tv/topic/75105-model-analysis-and-discussion-27th-nov-onward/

Technical discussion - for the more high end technical discussion surrounding the models and the various other factors around the output.

http://forum.netweat...del-discussion/

Model mayhem - all the emotion from looking at the models, rants, ramps etc

http://forum.netweat...n-ramp-go-nuts/

Please do try to make sure your post fits in with the theme of the thread you're using. Double posting is fine if for instance you think a post may be relevant in both this thread and the summary thread please feel free to copy it across

Thanks

Paul

[Matty M]

Reasonable improvement with low angle and stronger pressure at 60hrs. (6z)

Today's ECM EPS pick is run 15.. keeps us in cold locker throughout.

believe !

[snow drift]

1. The hunt for cold. More heights to the NW please with the pressure to the NE moving west.Or rubbish charts, so I can get on with some work instead of organising myself around the next set of output that is due out.
   

[leemondo]

I think we all need to take a step back and look at whats happened over the last week, also look at the date, less than 2 weeks into winter and we have already seen snow in alot of places.

Things can, and will change, last week is perfect example, i know that Atlantic driven weather is easier to model and predict, but thats because our weather is driven by it, to see a potentialy epic cold spell downgraded to almost nothing is gutting, but as i said, we are less than 2 weeks in so all to play for, but due to the location of our little island we are always subject to shortwaves (everytime i see that word i want to scream!) and the Atlantic is ALWAYS keeping a watch over us, thats just the way it is.

I'm a coldie through and through, but lets not get all depressed and think winters over when its only just started, the pattern is a vast improvment on last year which can only be a good thing, just might take a few more attempts to get what we want

[Matty M]

An improvement but no real mccoy.

In future runs we need the Atlantic LP to eject more towards Galicia.

We are short on time but it can happen.

[kate1]

I think we all need to take a step back and look at whats happened over the last week, also look at the date, less than 2 weeks into winter and we have already seen snow in alot of places.

Things can, and will change, last week is perfect example, i know that Atlantic driven weather is easier to model and predict, but thats because our weather is driven by it, to see a potentialy epic cold spell downgraded to almost nothing is gutting, but as i said, we are less than 2 weeks in so all to play for, but due to the location of our little island we are always subject to shortwaves (everytime i see that word i want to scream!) and the Atlantic is ALWAYS keeping a watch over us, thats just the way it is.

I'm a coldie through and through, but lets not get all depressed and think winters over when its only just started, the pattern is a vast improvment on last year which can only be a good thing, just might take a few more attempts to get what we want

Well said - personally I've thought all along that early-mid January gives us a more realistic shot at cold, just because that timeframe fits in better with what the background signals are telling us. The models are nothing like as discouraging as this time last year.

[Severe Siberian icy blast]

Well said - personally I've thought all along that early-mid January gives us a more realistic shot at cold, just because that timeframe fits in better with what the background signals are telling us. The models are nothing like as discouraging as this time last year.

Disagree , this December has very very strong signals pointing toward A cold December. So much so GP had 80% confidence of his forecast which was anything from 1-4c below normal.

[Barry12]

What are the chances of the cold winning out? Seems like the Atlantic is being pushed back Further south on every run.

[Snowly does it]

Out to T120 and no dice for cold. I think we are looking for assistance from an Azores ridge to GL in about 9 days time to move things on from stalemate. The 06z position by 120 is grim, dumbbell LP tilting sw-ne.

On the other hand, jet is south and heights OK in the usual places. Azores is going to be our friend (as long as it doesn't migrate and it and the Siberian HP combine into a euro high or worse a tip of Iberia to Lapland HP

[TEITS]

First sign of undercutting.

[bluearmy]

Disagree , this December has very very strong signals pointing toward A cold December. So much so GP had 80% confidence of his forecast which was anything from 1-4c below normal.

and it will be shaun. dont confuse 'below av temps' with 'guaranteed snow cover'. thats like saying the team with the most corners always wins.

[Snowly does it]

What are the chances of the cold winning out? Seems like the Atlantic is being pushed back Further south on every run.

This week? 1%

After the weekend? Probably 50/50 for a return to cold after Tuesday/Weds next weekl based on ensembles and background indicators (that's on opinion, not a scientific 50/50)

Edited December 10, 2012 by snowmaiden

[bluearmy]

not sure the shortwave off the eastern seaboard will drive the west atlantic ridge on this run

[Snowly does it]

not sure the shortwave off the eastern seaboard will drive the west atlantic ridge on this run

Hmmmm, there goes the saver. Still, at T150 it's all on a knife edge for how things pan out. Siberian HP is more westerly

[stainesbloke]

and it will be shaun. dont confuse 'below av temps' with 'guaranteed snow cover'. thats like saying the team with the most corners always wins.

Yes, unfortunately colder than average doesn't mean snow. So far Dec has not followed normal patterns, some areas have seen significant snowfall which is unusual for this early in winter. Plenty of time to get more favourable synoptics, with blocking patterns remaining in some form. Keep optimistic

[Methuselah]

Not that that LP's all that warm anyway: http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20121210;time=06;ext=171;file=h850t850eu;sess=f0f5b3ef42dfe3e633381d51d1d7395b;

[chionomaniac]

Remember, we are looking at the situation (continually forecast) where the Atlantic troughs are cut off from the main polar vortex. This situation is far more favourable than the one where the troughs are conjoined to the vortex and, whilst this situation remains, there will be the chance for pressure to build in between these troughs and the main body of the vortex.

[TEITS]

Remember, we are looking at the situation (continually forecast) where the Atlantic troughs are cut off from the main polar vortex. This situation is far more favourable than the one where the troughs are conjoined to the vortex and, whilst this situation remains, there will be the chance for pressure to build in between these troughs and the main body of the vortex.

Best way to describe the 06Z & ECM is loaded with potential.

Im also spotting the trend that the LP at +72 is slowly being moved further S.

[chris55]

Two points of interest for me this morning,

Firstly, is the initial attack from the Atlantic at the end of the working week, ECM lessons the influence of the little shortwave moving into the north on Thursday, in turn limiting the phasing of the warmer 850s over the UK and increasing the risk of some initial snowfall as the fronts move in, nothing to exciting at this point, and it's hard to tell exactly where the fronts are within this. We may get some warmer air in ahead of the fronts as shown on the FAX charts, but this could well change as we head nearer the time.

Secondly is the Russian high, although it can sometime be more of a hindrance for us, just sitting there and leaving us in no mans land! This set up looks a little different to, we have a very southerly biased Jet stream and the northern arm is less influential than normal,

Also factor in the fact that telleconnections are pointing to the possibility of height rises around Greenland and it wouldn't take to much of a change to get the Atlantic under the high and allow full on Retrogression!!

All a bit theoretical I know, but you never know eh!

That cold pool on ECM FI would sure be a nice Xmas pressie,

[Snowly does it]

Mid Atlantic ridge is definitely the way out of this. And it's graupelling outside

[LomondSnowstorm]

There's been a continual trend over the last few runs to move at least the 0C uppers further south, and on many of this morning's runs uppers stay below -2C across central and northern Scotland for the majority of the high resolution period. This may not make a huge difference to most but for the skiing industry at least this is very promising and with further slight upgrades and southward movement of the trough the potential for longer lasting cold and snow to even lower ground in Scotland and the far north of England will grow.

[Severe Siberian icy blast]

Best way to describe the 06Z & ECM is loaded with potential.

Im also spotting the trend that the LP at +72 is slowly being moved further S.

Ok yes the 06z looks better than the 00z , you can see high pressure retrogressing to Greenland from scandi, it's doing this well by t180 but I'm sick of the word "potential" we'v been using this word for 6wks and so far although we have been coldish with snow in places, I remeber this last 2wks or so for 2 massive near misses rather than anything else I'm afraid.

[chris55]

Disagree , this December has very very strong signals pointing toward A cold December. So much so GP had 80% confidence of his forecast which was anything from 1-4c below normal.

We are currently running 2.1c below average so spot on so far!!!

[Snowly does it]

Ok, the 06z is not going to pay ball, ridge fails. The ingredients are all there, but it will be days before any certainty can come into play.

Watch the ensembles for Dec 18 onwards, they will show the likelihood of striking gold

Edited December 10, 2012 by snowmaiden

[TEITS]

Ok yes the 06z looks better than the 00z , you can see high pressure retrogressing to Greenland from scandi, it's doing this well by t180 but I'm sick of the word "potential" we'v been using this word for 6wks and so far although we have been coldish with snow in places, I remeber this last 2wks or so for 2 massive near misses rather than anything else I'm afraid.

Time to move on and forget about the recent disappointments and accept this is what happens sometimes in the UK.

The overall pattern is miles better than some of the awful winters I have experienced as Chris explained perfectly.