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

[pyrotech]

I still find watching the models thru this period interesting

take ECM for instance, its 00 runs since friday night have consistantly moved the low Southwards. So much so that in that time frame the winds have moved at least 45 deg from SW to SE on the south coast of uk by 00 FRiday this week, same movement again in same timeframe ie 3 days and we have an Easterly ( albeit not as potently cold as it could have been. So things hang onto more of a knife edge than we give credit to.

Then we have most major models showing a sometimes wet and certainly less cold outlook to run up to Christmas. ECM and GFS both are loaded with potential in fi, but the models just do not show it coming to fruitition. The Ensembles are also not really reflecting a cold run up in fi either. However a weeks ago the Easterly and potential was equally shown by all models and even in the Meto outlook they hinted towards cold, but whilst still in fi it changed dramatically over less than 24 hours by all. Nothing really has changed, the models still show a very complicated outcome for fi and i just do not understand why we believe fi when it shows less cold more than when it shows cold. ECM and GFS only have 50% accuracy in fi. We are looking for triggers to cause changes in the models and to me its loaded with potential and although the models do not show a 50 / 50 scenario, i believe it is equally balanced to go colder around 23rd as it is to remain zonal.

[Troubleatmill]

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.

Indeed, we are are always on the lookout for another 2010, who knows we may yet as the the NH is definately not in default zonal.

Its simply a case of unfortunatly things havnt gone as we had hoped for snow and deep cold, but it all makes model watching interesting as we a learn so much more when we are in these set ups, as they dont happen every year.

Edited December 10, 2012 by Nick JB

[latitude]

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

The problem is people get confused with 'below average' meaning snow. The temperatures can be below average for the whole of December but dosent mean snow for the vast majority. Its amazing how the models have morfed into a total non event this week apart from crisp frosty mornings.

Edited December 10, 2012 by latitude

[EML Network]

Well the 06z has got to be the most awful run yet if you are looking at it for potential cold and snow (which let's face it most of us on here do).

And to end it all off, we end up with the beginnings of a Bartlett High...ohh well...there's always next winter (JOKE)

[MR EXTREMES]

gefs has slightly below average temps all the way through the run.

i do expect northern england and scotland to do very well with some wintry stuff.

so to sum up even in the south temps will be slightly below and windy wet.

to the north hills and moutains doing well with possible lower levels from time to time.

after this im optimistic hope the vortex re locates sooner than later.

and would love to see a nice early canadian warming event to.

[chionomaniac]

Well the 06z has got to be the most awful run yet if you are looking at it for potential cold and snow (which let's face it most of us on here do).

And to end it all off, we end up with the beginnings of a Bartlett High...ohh well...there's always next winter (JOKE)

I disagree entirely EML.

For potential this run has a lot and whilst the Atlantic troughs don't attach themselves to the vortex in the reliable that potential will remain.

[latitude]

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.

Well the 06z has got to be the most awful run yet if you are looking at it for potential cold and snow (which let's face it most of us on here do).

And to end it all off, we end up with the beginnings of a Bartlett High...ohh well...there's always next winter (JOKE)

Now that is confusing for any new member or someone trying to understand the models!!

[chionomaniac]

gefs has slightly below average temps all the way through the run.

i do expect northern england and scotland to do very well with some wintry stuff.

so to sum up even in the south temps will be slightly below and windy wet.

to the north hills and moutains doing well with possible lower levels from time to time.

after this im optimistic hope the vortex re locates sooner than later.

and would love to see a nice early canadian warming event to.

I have given up on a CW badboy. I am now looking at a full blown SSW early January.

[MR EXTREMES]

Well the 06z has got to be the most awful run yet if you are looking at it for potential cold and snow (which let's face it most of us on here do).

And to end it all off, we end up with the beginnings of a Bartlett High...ohh well...there's always next winter (JOKE)

i really cant see a bartlett forming i think tele dont support this with russian heights that strong and no sinker i this bartlett is a no go.

lets get this period of unsettled weather out the way see where the vortex ends up and keep a cold eastern europe then the chances will come.

i think looking north would be a more likely outcome or even a northeasterly in time.

[Shunter]

This is an evolving synoptic situation , one which I am finding extremely intriguing. Every gfs run is moving the trough steadily south. As the PV migrates so the pressures will balance and force the Russian hp cell westwards . We may not get the snow we desire ( yet), but I will gamble the next 24-36 hours will show a more positive cold solution for the UK.

[Froze were the Days]

GFS 06 run trending even further away from a possible easterly in the medium term, just a small ridge makes it in from the continent before sinking south and then possibly some very mild air towards FI. At least it doesn't look like at the moment we are going to be 'strung' along like the last 2 episodes, sad thing is there always seems to be a Russian High or Siberian high present but not doing enough to largely effect our weather in terms of significant cold, but as mentioned the synoptics were far worse this time last year let's just hope we now don't go into a phase of mild mobile Atlantic conditions later in the month.

Just looking at the ECM certainly has potential later in the run - one to keep an eye on, possible undercutting?

Edited December 10, 2012 by Froze were the Days

[stainesbloke]

Well the 06z has got to be the most awful run yet if you are looking at it for potential cold and snow (which let's face it most of us on here do).

And to end it all off, we end up with the beginnings of a Bartlett High...ohh well...there's always next winter (JOKE)

Disagree, still think there is potential. Please stop posting vile charts deep in FI, it's not gonna happen!

[Ian Brown]

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.

That is certainly what I’m looking at, there is great potential for Northern blocking as cut-off Atlantic Lows decline. I know people will point to the previous let down and/or the fact that the GFS fires up the jet later on resulting in pressure rising from the South, but I think from historical synoptics there is a decent chance of something much different from day 9 onwards.

[SLEETY]

I see the -25c line has appeared on the ECM ensembles again.

Trending colder again with some very cold looking ensembles for London as well

Not that i;m straw-clutching or anything!

Edited December 10, 2012 by SLEETY

[snowmadchrisuk]

Well the 06z has got to be the most awful run yet if you are looking at it for potential cold and snow (which let's face it most of us on here do).

And to end it all off, we end up with the beginnings of a Bartlett High...ohh well...there's always next winter (JOKE)

Do you have your comments on speed dial, you wrote (word for word) that exact same comment early last week .....

[pyrotech]

GFS 06 run trending even further away from a possible easterly in the medium term, just a small ridge makes it in from the continent before sinking south and then possibly some very mild air towards FI. At least it doesn't look like at the moment we are going to be 'strung' along like the last 2 episodes, sad thing is there always seems to be a Russian High or Siberian high present but not doing enough to largely effect our weather in terms of significant cold, but as mentioned the synoptics were far worse this time last year let's just hope we now don't go into a phase of mild mobile Atlantic conditions later in the month.

Just looking at the ECM certainly has potential later in the run - one to keep an eye on, possible undercutting?

I agree, but bare in mind statistcally ECM is more reliable at days 2 - 5 but then later in fi they are much closer in accuracy where both fall off rather dramatically and ECM becomes only very marginally better than GFS if at all. Apparently Meto run with ECM for medium range - 10 day but im not sure why they have such faith, as around the end of Fi both are in huge margins of error. I think we need to use intuition and just look for triggers for patern changes in blocking in the models when looking in Fi, i normally say trends but that does not seem to work in these situations, unless you call the trend as showing potential cold.

[Frosty.]

The Gfs 06z really does keep us in the hunt for cold, just some small adjustments and we would be into a much colder looking outlook but as it is, the outlook shows a very unsettled spell with mostly below average temps, any milder weather looks very brief indeed, mostly it should be feeling cold at least given the strength of the mainly cyclonic winds which will be strong at times. The 6z keeps us interested in the russian high and even in the depths of FI we almost tap into the bitter cold as it clips the far northeast, who is to say we won't find the right combination to unlock a truly cold spell this side of christmas, as long as the block is close, we have a shot but we also need patience. As for this week, cold for most of the week with frosty nights, sunny spells and some freezing fog until midweek, then we develop a SEly which will be raw and unsettled weather will start to spread northeast, some snow in the mix at first and a real chance of disruptive snow for a time on the hills of central and northern britain, even blizzards for the hills/mountains in scotland later in the week, just the far south becoming briefly mild later in the week but the weekend and into next week looks rather cold and cyclonic with spells of rain and a continued risk of snow on northern hills.

[bluearmy]

I see the -25c line has appeared on the ECM ensembles again.

Trending colder again with some very cold looking ensembles for London as well

Not that i;m straw-clutching or anything!

the ecm op run has a chunk of siberian vortex managing to get around the russian block into eastern europe. hence the need for the lower scale. infact the spread on 850's shows an appetite to bring lower uppers into eastern europe day 10.

[chris55]

GEM sets up a Greenland high in FI, although I don't get why the Wetter and Metiocel versions are different to each other????

Edited December 10, 2012 by chris55

[bluearmy]

GEM sets up a Greenland high in FI, although I don't get why the Wetter and Metiocel version are different to each other????

the wz one appears to be generated by steve murr !! i checked meteocentre yesterday and the meteociel one is the correct outptut for the global model. no idea what run wz is showing

[snowking]

GEM sets up a Greenland high in FI, although I don't get why the Wetter and Metiocel versions are different to each other????

As far as I know the WZ one is an older data set - lower resolution. Meteociel (and shortly NW from what Paul was saying yesterday) have the newer hi res GRiB data

SK

[Suburban Streamer]

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.

But its perfectly possible to have potential and near misses. Without potential there is no chance. I'd much rather have potential like this, than have a December like last year. Yes we have been unlucky so far but as long as potential remains, there also remains a decent chance. If u want to be sick of something, then be sick of our bad luck so far!

Still below average December to date.....fingers crossed for the next episode

Edited December 10, 2012 by Suburban Streamer

[Frosty.]

A very interesting gfs 6z run, we do get close at times to a much colder spell so we are really in with a shout if we have a bit more luck, synoptically we are in a much healthier state than early last winter.

[Geordiesnow]

I look at the output and I can't help but feel what a waste that 1050MB high could be, if it was not for that shortwave, the outlook would be totally different - not saying it would be a snowy one but you imagine any blocking would be much further West.

The charts do have potential(yawn) but I say any cold shot at this stage is very low risk indeed, when you got two massive weather systems(the big blocking high and the large Atlantic low) then we are in a situation where we are just in a stalemate and for cold lovers, our hope is that the somehow wins out but at least for the UK, this looks a long way from doing so.

That said, cold set ups are more likely to occur if they pop up at around 120-144 unexpectedly, so its certainly going to be interesting model watching especially seeing we are in a position for nothing to lose I suppose.

Obviously, we need to keep an eye on rainfall amounts, especially in the SW although I don't see much in the way of stalling weather fronts appearing around there on the model output at the moment.

[Severe Siberian icy blast]

I have given up on a CW badboy. I am now looking at a full blown SSW early January.

Morning Ed , it was only two days ago you were talking about a Canadian warming in the near future, But then yesterday you began to see signs of a full in SSW early new year, can I ask why the sudden change of thought apart from what was showin in the models , because you seemed very keen of a CW for a long time , so so my point is , if things can change quite quickly , what's to say this next sign won't be another false dawn?