Winter Model Discussion Thread 12Z onwards 5/1/13

[karlos1983]

The 12z really can't come soon enough, I can feel the anxiety in this Forum, luckily for me I've got an Arsenal match to make the time go quicker, I'm about as confident of that result as a lengthy cold spell at the moment, well and truly on the fence!

[swfc]

Was that on countryfile weather at end?

it was before country file started

[Robbie Garrett]

Thanks mate. That helps, my knowledge of the stratosphere at the moment is basic. I take it the response times to a SSW do vary from time to time and I suspect we've been caught lucky with high pressure over the UK being able to retrogress?

Hi Robbie

The effects from the stratosphere have no set lag time associated with them. It all depends on how quickly we see the effects downwell into the troposphere, and a whole array of factors help to determine this (zonal wind budget in the troposphere, QBO, EP Flux, Wave Activity etc.). An SSW can initiate an instant response in the troposphere, but equally sometimes it takes a few weeks before we see anything. In this instance it seems that we get some sort of instant response with a weakening and split of the Polar Vortex in the next 10 days or so

SK

[Jason M]

Well bbc week ahead, stalling front to the west as we get to WED/Thurs with heaviest precip to SW and further east along s coast on Fri This is because Pressure rises to our NE and holds the front up and some of the trough begins to slide SE. Then he went on to say that SOME computer models 'SOME' show HP building to north bringing cold E'lies....but uncertain this far out. Take from it what you will.......they aren't convinced yet but are quite interested.

BFTP

Seems to me that the evidence of an easterly is now very strong indeed. The issue really is what happens next?

The problem is that the start of the old spell is effectively at day 5, but by its vey definition confidence drops away very quickly after day 5.

Jason

[The PIT]

Chris Fawkes hasn't said anything In particularly but said 'couldn't resist putting this in, some of the computer models saying high pressure to our north east bringing in a colder feed which would cause temperatures to drop well below normal' or something along those lines I couldn't type fast enough on my phone as he was saying it!

I saw that as well. That's him in the office then on Monday. Also Daily Mail headlines of Met Office confirms deep freeze by the 12th. Temps plunging to -15C. If it doesn't happen bad news for the met office as the press will crucify them. Barbie summer anyone? He'll be hoping for the ECM solution -12c uppers over us which is rather more aggressive than the GFS.

Edited January 6, 2013 by The PIT

[ChartViewer]

The 12z really can't come soon enough, I can feel the anxiety in this Forum, luckily for me I've got an Arsenal match to make the time go quicker, I'm about as confident of that result as a lengthy cold spell at the moment, well and truly on the fence!

Knowing our luck Arsenal will lose go out the FA Cup and the ECM/UKMO/BOM will go belly up!!!...On a positive note we could beat Swansea and the GFS comes into line............roll on the 12z's!!!!

Edited January 6, 2013 by ChartViewer

[Dexter29]

Countryfile forecast made a nice change to the recent drab.

Chris confirmed the uncertainty in some models, but the fact he showed what the potential of certain models could have for the UK next weekend was great to hear.

Although the SW and SE Wales on his forecast looked like having some pretty wet weather during the week, especially Thursday. Certainly not good news for the flood areas.

Temps ranging from 6c in the north to 9c in the south come Friday. Hardly what I would call cold, but compared to the recent mild dross it will feel decidedly chilly especially for northern areas.

[IDO]

Well if anybody thought there was any confidence in D4+ output, the Greenland ensembles shows that we can expect a lot of changes in the short term model output going forward:

GFS 06z ens Nuuk:

It does however suggest that the GFS modelling of the PV around W. Greenland may be an outlier.

Edited January 6, 2013 by i'm dreaming of...

[fergieweather]

I saw that as well. That's him in the office then on Monday. Also Daily Mail headlines of Met Office confirms deep freeze by the 12th. Temps plunging to -15C. If it doesn't happen bad news for the met office as the press will crucify them. Barbie summer anyone? He'll be hoping for the ECM solution -12c uppers over us which is rather more aggressive than the GFS.

? Chris expressed the uncertainty. As will UKMO to the press. They've hardly ramped it.

[nick sussex]

Although the ECM operational run sticks to its trend its got no support from the GFS or UKMO at 144hrs.

Regardless of the other models these three really need to be in agreement to have more confidence going forward.

The positive here is that we're not talking of a cold versus mild outcome but simply how cold, snow potential and longevity of a colder pattern.

So its very likely to turn colder but thats all we really can take from the output at the moment.

[Methuselah]

Knowing our luck Arsenal will lose go out the FA Cup and the ECM/UKMO/BOM will go belly up!!!...On a positive note we could beat Swansea and the GFS comes into line............roll on the 12z's!!!!

Is that necessarily a bad thing?

But, still, models are trending better with each run...

I saw that as well. That's him in the office then on Monday. Also Daily Mail headlines of Met Office confirms deep freeze by the 12th. Temps plunging to -15C. If it doesn't happen bad news for the met office as the press will crucify them. Barbie summer anyone? He'll be hoping for the ECM solution -12c uppers over us which is rather more aggressive than the GFS.

That's blown it!

? Chris expressed the uncertainty. As will UKMO to the press. They've hardly ramped it.

Indeed they haven't, Ian...Not that that's ever going to deter the Mail form its policy of continual misrepresentation?

[The Northern Ramper]

? Chris expressed the uncertainty. As will UKMO to the press. They've hardly ramped it.

They don't need to ramp it, the Express or Mail will take care of that.

[Summer Sun]

The current take on next weekend

It should be noted that Chris expressed the uncertainty in this for the end of the week so anyone who gets there hopes up to much could be sadly disappointed

Here is the forecast its self

Edited January 6, 2013 by Gavin.

[TheBigFreeze]

Hi again and please feel free to delete this mods, but as a newbie, is there a post anywhere which gives a guide to the different models and all the different terminology and the way everything interacts, like heights, uppers, ensembles, anomalies etc would like to try and get my head around things a bit more..thanks in advance

[The PIT]

It should be noted that Chris expressed the uncertainty in this for the end of the week so anyone who gets there hopes up to much could be sadly disappointed

The press will ignore that plus weren't they warned not to make public announcements? I'll expect a slap on a wrist for him Monday when the bosses are back in.

[dancing daisy]

Hi again and please feel free to delete this mods, but as a newbie, is there a post anywhere which gives a guide to the different models and all the different terminology and the way everything interacts, like heights, uppers, ensembles, anomalies etc would like to try and get my head around things a bit more..thanks in advance

http://forum.netweather.tv/forum/24-learning-about-weather-and-meteorology/

[Summer Sun]

The press will ignore that plus weren't they warned not to make public announcements? I'll expect a slap on a wrist for him Monday when the bosses are back in.

John Hammond gave hints of something colder towards the end of last week I see nothing wrong with what Chris has said he expressed the uncertainty in this

[Met4Cast]

The press will ignore that plus weren't they warned not to make public announcements? I'll expect a slap on a wrist for him Monday when the bosses are back in.

Its a bit hard not to mention it when you're doing a week ahead forecast though isn't it?

[johnholmes]

To be fair to Ian this is what happened, whether or not he is on the wind up as well is to be decided.

It would be nice to get an opinion on what he thinks will happen rather than suggesting caution.

There are plenty of posts with my views and why-maybe yesterday page 20 of that model discussion No 396 explains my stance

Re the comment from Ian about 500mb charts. They did predict it but I missed it and gave a reasonably full account of this soon after it happened. No idea where on the forum it is now though.

[Iceni]

All will be ok because our good old friend 'Mr Swan' is back to protect us from any nasty Atlantic mild weather

I think it's a snow goose, not a swan

[Frosty.]

Well it's looking much more like a cold spell ahead which may become a memorable period of cold/snow, in complete contrast to the absolute rubbish we have had in the run up to christmas with all the horrible flooding, and then the mild bland cloudy dross over christmas and thus far into the new year, at long last it looks like a big change is coming with temps on the slide after tuesday, back down to 6-8c after midweek (average), then colder by the weekend with wintry showers spreading in from the northeast and frosty nights.

So we can put the wheely bin away and look forward to charts like that in the not too distant future.

[TheBigFreeze]

http://forum.netweat...nd-meteorology/

Thank you

[johnholmes]

Hi and thanks for your reply,

I'm beginning to get the idea that I should take anything past say 120h with a pinch of salt, and that to compare models and look for trends, and model alignment, however i'm still at a very novice stage, and just trying to get to grips with what the models are actually showing and doing, which is why I was asking is what I stated about that model correct in what I thought it was showing, as opposed to this is what I think will happen....sorry if that wasn't very clear

don't be afraid to ask questions, we all learn from each other. Try the Guides they may well help in explaining some things to you and welcome to Net Wx.

[SnOwFeSt]

Jeez, I thought some sort of big downgrade he occurred looking at the mood on this forum. Checked the outputs and still looking frigid come the end of the week, with meg whiteout type stuff deep in FI.

I for one look forward to the chopping and changing over the coming days. It's probably 50/50 as to whether it will be cold and dry or whether there will be some widespread snow events from this. Either way I'd say that the colder weather is increasingly looking nailed for the end of the week.

[johnholmes]

Hi again and please feel free to delete this mods, but as a newbie, is there a post anywhere which gives a guide to the different models and all the different terminology and the way everything interacts, like heights, uppers, ensembles, anomalies etc would like to try and get my head around things a bit more..thanks in advance

hi

see my other post, go to the Guides section and browse around there. Ask questions by all means.