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

[Frosty.]

I wouldn't say they've 'written off January', it looks more along the lines of there being no strong signal either way in the 16-30 day range with cyclonic conditions favoured up to the start of January in some form or another.

True but reading it creates a sinking feeling, they are supposed to be experts, anyway, at least some parts of the north could have snow, at least on hills later this week and weekend, still a hint of colder showery weather next week for a few days at least before the pattern flattens out.

[Troubleatmill]

They did very well in the build up to the Dec 2010 freeze but I agree there is still a lot of model uncertainty and I really don't know how they can be so dismissive of cold air affecting more of the uk in the next 10-15 days.

Think its because they are prety clever people, impossible to be sure i agree, and doubt they are 100%, but if the met say we are going to locked into this for a fortnight (its not that long in pattern terms) its prety much a given i reckon

[UV-RAY]

Going off all the models and MetO, I would say the odds of a cold spell in January are about 30% at best.

[Buriedundersnow]

well another interesting couple of runs from the gfs last 00z and 06z still wanting to go for that undercut just before christmas and thats as far as i am going to look just now the 22nd--23rd is where it is for me as to wether we will see that undercut or not and thats where i feel it all hinges and wait to see what upgrades come in the next few days as i feel if we get that undercut we might not have the russian high move west but can it leave something behind as a parting christmas gift around the scandanavian area

[Bobby]

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Edited December 18, 2012 by Bobby

[-uksnow-]

Going off all the models and MetO, I would say the odds of a cold spell in January are about 30% at best.

Why say that, with no evidance to back it up just a completely ridiculous post? Dont post unless there is substance or reasoning to your beleif.

[Bobby]

Looks like flooding may become the big issue this week, I see little sign of any cold for the foreseeable that's for sure

BBC News mentioned up to 3 inches of rain parts of the SW in 36 hours tomorrow and Thursday

NMM rain totals tomorrow/Thursday

then another big mass moves in Friday/Saturday (GFS 06z)

Some places could see 4inches/100mm in a few days

[Tim Bland]

with all due respect guys the met has access to mor data to what we have here at nw. Also don't the met have a new computer that forecasts the status of the strat? From chios and gp's posts in the strat thread it sounds good, how ever it seems that reading u guys posts here the met r not buying into the strat warming. The question is y? If they bought into the strat warming they wouldnt be riting off jan. I would be entrested to heare your thorts chio and gp.

Hi syed, The Stratospheric tempreature has a link to what happens to the state of the polar Vortex. All we have at the moment is a forecast for a warming event to take place. *If* the warming occours then it will take weeks maybe even a month to have an effect on the PV. IT also doesnt guarantee that the PV will distort to our advantage and we could still be under average conditions.

With this in mind I dont blame the Meto for not jumping to a snowmagedon forecast just because there is a warning forecast, they will want to see this materialise and then see its affects on the NH. IMO the Meto.. just like us are a bit clueless as to what the weather will do after new year hence their line "no paticular weather types are favoured"

Models are all over the place at the moment. I am off to Prague in Chezch Republic next week and the conditions there could be anything from +5c to -5c going by recent runs. I just looked at 2 online forecasts for 26th, one had a had a max of +5C and one had a max of -6c lol. so its not just our part of Europe that is unable to plan for the festive week ATM.

[LomondSnowstorm]

I find the idea of writing off an entire month on the basis of one 30 day outlook that only goes up to the 15th pretty daft to be honest. The strat warming will create a lot of volatility in the long range forecast and we're not able to say what the tropospheric implications of it will be yet anyway.

[latitude]

I find the idea of writing off an entire month on the basis of one 30 day outlook that only goes up to the 15th pretty daft to be honest. The strat warming will create a lot of volatility in the long range forecast and we're not able to say what the tropospheric implications of it will be yet anyway.

If it happens, and right now it hasent.

[UV-RAY]

Why say that, with no evidance to back it up just a completely ridiculous post? Dont post unless there is substance or reasoning to your beleif.

All of the LRF models are going for a zonal January, now some may not place too much faith in these but when you have a full house all singing from the same hymn sheet then ignore them at your peril. I think too many place all their faith on teleconnections and strat warming, none of these guarantee the UK cold, they are just indicators of the overall NH pattern. Until we start seeing updates from the MetO about changes in the long wave pattern, then any wishes for cold are hope casting at best. Edited December 18, 2012 by Seven of Nine

[wolvesfan]

with all due respect guys the met has access to mor data to what we have here at nw. Also don't the met have a new computer that forecasts the status of the strat? From chios and gp's posts in the strat thread it sounds good, how ever it seems that reading u guys posts here the met r not buying into the strat warming. The question is y? If they bought into the strat warming they wouldnt be riting off jan. I would be entrested to heare your thorts chio and gp.

Agreed,the met over the past couple of winters have called things pretty accurately IMO in the medium and long range forecasts.i find them an excellent tool to use inconjunction with the various model output,and reading between the lines they give you a good idea of which of the models they are favouring.from a cold lovers perspective though there text forecast like the models dosn't always make for good viewing.

[LomondSnowstorm]

If it happens, and right now it hasent.

True, I should've added 'forecast warming'. Forecasting of it though has been relatively robust though and while the details will change a bit it does look like we are heading towards a significant warming (whether SSW is achieved or whether we have an additional Canadian warming at lower levels are interesting and important issues to be resolved).

[latitude]

True, I should've added 'forecast warming'. Forecasting of it though has been relatively robust though and while the details will change a bit it does look like we are heading towards a significant warming (whether SSW is achieved or whether we have an additional Canadian warming at lower levels are interesting and important issues to be resolved).

Fair enough. But as people have previously said, we can have all the signals, loads of strat warming, brilliant 500mb charts.....but one short wave can mess it up for the whole of the UK. Think people are realising this now, that background signals and are nice, but not that meaningful for our litte island next to the big Atlantic.

Edited December 18, 2012 by latitude

[mountain shadow]

Agree with the comments about a zonal January however this doesnt mean no snow.

If a portion of the PV drops into Scandinavia we will have a heck of a lot of cold air within touching distance which any height rises towards Greenland will assist with.

Grasping for any straws i know.

[LomondSnowstorm]

Fair enough. But as people have previously said, we can have all the signals, loads of strat warming, brilliant 500mb charts.....but one short wave can mess it up for the whole of the UK. Think people are realising this now, that background signals and are nice, but not that meaningful for our litte island next to the big Atlantic.

Well it's always a struggle to get deep cold here, particularly from a Russian high, and there are never any guarantees for any particular location, but we did have a period of significantly below average temperatures, so the forecasts weren't a complete write off.

It is surely better to have positive background signals going forward than to be stuck with a limpet PV sitting over Greenland and a dominant positive AO, because from there we have almost no chance of seeing anything below average.

[phil nw.]

Looking at the latest fax`s we can see that small low development along the approaching Atlantic fronts as they struggle northeast across the UK

This trough disruption has caused the minor differences in short term modelling and different runs have placed these smaller features or wave developments slightly differently but now at a closer timeframe we can see with the aid of human imput these issues are now being resolved.

Main guidance from the models for this weeks eventual Atlantic pattern coming through has always been with the wider picture both from upstream with the jet forecast and the overall 500hPa Northern hemisphere pattern.

These have been pointing the same way for some days.Sometimes it pays to take a step back from studying every changed isobar and look at the overall pattern and see how close that is amongst the models,

Saves a lot of confusions sometimes.

[The watcher]

Agreed,the met over the past couple of winters have called things pretty accurately IMO in the medium and long range forecasts.i find them an excellent tool to use inconjunction with the various model output,and reading between the lines they give you a good idea of which of the models they are favouring.from a cold lovers perspective though there text forecast like the models dosn't always make for good viewing.

I know all this Meto Talk is off topic, so apologies as this will be deleted at some point.

I recall just a few weeks ago when it looked like the BFTE was about to establish itself over the UK, that the Met had said in their 15-30 day outlook for December we were heading for a below average period of temperatures with widespread frost, some snow et all. When the models changed their outlook, so did the Metoffice. So in any case, when the models change, so will they. Right now there is some uncertainty in the model outlook, but the in favor synoptic is for an average to above average setup with mostly unsettled conditions, so no change is needed to their outlook until they deem fit to do so in regards to what Model Output is saying is the most likely outcome.

[Winter Monsoon]

All of the LRF models are going for a zonal January, now some may not place too much faith in these but when you have a full house all singing from the same hymn sheet then ignore them at your peril. I think too many place all their faith on teleconnections and strat warming, none of these guarantee the UK cold, they are just indicators of the overall NH pattern. Until we start seeing updates from the MetO about changes in the long wave pattern, then any wishes for cold are hope casting at best.

Eh?

Let me get this right, your writing off jan on the here say of the Meto (thats basically what it is) and because all 'LRF' models say no to cold?? The same Meto and models that recently all predicted an easterly at the same time so all singing from the same hymm sheet that NEVER materialised. On the same models that currently cant decide whats going to happen after +144 Let alone next month??

You choose to ingore the fact that we currently have a displaced PV and will currently continue to see a displced PV right upto the 'Forcast Warmng' I think that thats a prettty rare event, so considering this dont you think that the Meto (who are always right yes?) and ALL models are going to strugle.

[nick sussex]

I think a good analogy to sum up the last few weeks in the models is to equate it to a football match where one side dominates has loads of chances to score plays lovely football but can't score and the other team bundles in a messy goal right at the end.

Alternatively its like having some five star ingredients and making a crap dinner!

Southerly tracking jet

Arctic high

Russian high

Displaced PV

And the sum total really hasn't added up to much for the majority of the UK, so we can see even though you might have an overall NH pattern that gives chances for cold into the UK, the finer detail is always the decider.

Edited December 18, 2012 by nick sussex

[BLAST FROM THE PAST]

Never mind deep cold or heavy snow, there may be another Xmas menace for travel. The potential flood threat this week and then again on weekend, and also the potential gale force wind threat. A very disturbed pattern looking likely and also tracking across the UK so some very strong winds inland to boot.

I actually am liking the look of the pattern that could develop ahead. New Year could produce some early 2013 cold but an active pattern with LPs on a track that hits UK full on brings very interesting weather.

Personally, the only weather set up I dislike is mild, damp 1000 mile draw SW'lies.

BFTP

[UV-RAY]

Eh?

Let me get this right, your writing off jan on the here say of the Meto (thats basically what it is) and because all 'LRF' models say no to cold?? The same Meto and models that recently all predicted an easterly at the same time so all singing from the same hymm sheet that NEVER materialised. On the same models that currently cant decide whats going to happen after +144 Let alone next month??

You choose to ingore the fact that we currently have a displaced PV and will currently continue to see a displced PV right upto the 'Forcast Warmng' I think that thats a prettty rare event, so considering this dont you think that the Meto (who are always right yes?) and ALL models are going to strugle.

we've had a displaced Vortex for the last few weeks and I'm not writing off anything, a 30% chance of a cold spell in January is realistic not hopecasting. You refer to all the teleconnections being favourable as if this guarantees us cold, it doesn't but it does increase our chances. Some need to take a more realistic approach to viewing the output and not let their cold prejudices cloud their judgement. Edited December 18, 2012 by Seven of Nine

[Methuselah]

Certainly going to be interesting to see who is right, my instinct Vs ECM/ensembles.

Well, after 10 years' trolling through charts, models, avian proclivities and the instincts of myself and others, I think I'll opt for the ensembles...I could of course be wrong, however!

We will see...

[The Eagle]

What we have is a delicate evolution and one that could bring more widespread snow within as early as 96hrs or at least a cold/mild collision over us so I wouldn't be too hung up on this mornings runs. 12z GME gives some hope. We need the lp to the west to become squeezed and elongated west east between hp to the north and the south. This is still a scenario on the models worth watching

Edited December 18, 2012 by The Eagle

[Frosty.]

Why say that, with no evidance to back it up just a completely ridiculous post? Dont post unless there is substance or reasoning to your beleif.

He's entitled to his opinion like anyone else, if he thinks there is a 30% chance next month he's probably not far wrong! there is no strong signal either way at the moment although the effects of stratospheric warming should create more chances of cold blocking next month, probably after mid month so the % should increase then.

Edited December 18, 2012 by Frosty039