Model Output Discussion: 12Z (02/12/12) And On...

[Summer Sun]

Looking at the charts the next snow event will be coming overnight Wednesday and into Thursday now depending on how long the cold air stays in the north we could be looking at a significant snowfall event with the rain moving in from the west there is the potential for several cm in places.

Certainly needs an eye on it that's for sure

[frosty ground]

Latest from Ops Centre:

" 4. Trend for Days 10-15 : Best estimate is to remain colder than average with frost more widespread than normal and some wintry ppn likely, especially in the N and E. Highest probs of milder, but wetter interludes are towards the W/SW.

5. Discussion : There are major differences between EC and MOGREPS through this period. Initially these differences are not too great, with both ensemble suites having a signal for a brief milder interlude early next week, especially across northern Britain. Thereafter a blocked pattern is expected to develop, but there are large differences between MOGREPS and EC with the detail of the block, with EC ensemble having a strong signal for an E’ly, whilst MOGREPS has a S’ly. NCEP ensemble appears to be roughly split 50/50 E’ly and S’ly. The EC solution has been favoured at the moment, with slightly more support, but with the caveat of occasional frontal incursions into at least in W’ern parts of the UK."

Just need to bump this back up the list.......... Please note this first hand account, I am not sure how this ties up with the post by Ian Brown.

[london-snow]

Im very open to upgrades, infact I will relish them because I adore snow and sharp frosts, but terry made a good point, it currently looks like the uk would end up with the dregs of the western limit of the cold as synoptically things have taken a downturn so far today, hoping for changes just like everyone else but we have seen this phony FI promise in the past, but it still looks like a cold outlook is probable with frost and freezing fog although the milder atlantic will probably end up being too close for comfort, at least for the south and west, the north and east might do better as the gfs 00z showed.

Frosty you are a self made roller coaster one minute down the next up lol.

Let's just be clear there is still major divergence between the output and more so the ensembles so jumping the gun from run to run would be non advisable especially those with a dodgy ticker...

A poster last night mentioned past instances where westward correction in the output is a frequent occurrence and provided charts to back that claim up. In this instance i feel the more westward correction in the pattern the better the outcome and the outlook. Hopefully that battle could commence somewhere in the Atlantic !!

Its a margins game and we are on the edge so the more west the pattern corrects the more the Atlantic will struggle to make inroads east when it comes up against colder air.

To the 12z output and the key time frame for me is in the medium/late 150+ range and look for westward correction with a knife edge situation such as the one we may well see. A difference of 100 miles per day x 6 days ( Where the easterly can set up ) = 600 miles and can make all the difference especially to those into the south and east.

I posted earlier and had a rant re the meto update. However on reflection it was a good update although highlighting the difficulty of the pattern going forward which is far from case solved. People including myself do not realize in the heat of the moment. That they are only commenting on the output in front of them and there forecast is updated daily so is not to be taken as pure gospel.

Anyway we await the 12z with keen and hopeful interest.

Edited December 4, 2012 by london-snow

[Frosty.]

Frosty you are a self made roller coaster one minute down the next up lol.

Actually I have been very positive about the cold outlook for the last month or so, it's only today where i'm wavering and it's no surprise because the gfs 6z shows a fired up atlantic blasting the block away to the northeast, it takes a bit of a pounding as the atlantic revs up, there is just a fleeting moment when we are in a col between the atlantic lows and cold anticyclonic block and then it's game set and match atlantic. The latest meto 6-15 day update has really toned down the wintry potential for northern, western and southern areas with milder intrusions likely but trending colder from midweek with a chance of wintry showers in the far east. The 6z does not show a milder monday as the meto say it's trending, indeed next monday and tuesday are cold with temps close to freezing, then the atlantic makes inroads, then it stalls and then it finally breaks through to the east of britain and beyond. This weekend is looking cold with our very own anticyclone slowly slipping south so a frosty and icy weekend with some freezing fog, the 6z shows this type of pattern persisting early next week with just some rain spreading across the far north with slightly milder air.

Edited December 4, 2012 by Frosty039

[Zenarcher]

Comparing the GFS runs from this morning to the ensembles and cluster maps the operational runs seem to be making many mistakes around 120 hours and beyond mainly with the shortwaves and low pressure systems, most ensembles seem to point out that it is being to progressive with them and this to me is not surprising because that sort of thing happens at that time frame. If the GFS 12z stamps out these mistakes expect a better run if not it might take another day before it starts improving.

[SLEETY]

Just need to bump this back up the list.......... Please note this first hand account, I am not sure how this ties up with the post by Ian Brown.

Ian ferguson is saying the actual pro forecasters at the met office are favouring the ec model output of an easterly flow rather than the mogreps model which prefers a southerly flow but a strong signal of a blocking high is expected to develop anyway.after the weekend

So the negativity in this forum today is puzzling and a little silly; dont people actually read what one of the met forcasters is posting in this forum, unless people think the pro forecasters at the met haven,t a clue what will happen, I think I know who I would believe more TBH

[Lynxus]

Ian ferguson is saying the actual pro forecasters at the met office are favouring the ec model output of an easterly flow rather than the mogreps model which prefers a southerly flow but a strong signal of a blocking high is expected to develop anyway.after the weekend

So the negativity in this forum today is puzzling and a little silly; dont people actually read what one of the met forcasters is posting in this forum, unless people think the pro forecasters at the met haven,t a clue what will happen, I think I know who I would believe more TBH

Just because they work for the METO doesnt mean they are correct. There are many experienced forecasters here who do not work for them. however they probably could do if they wanted to.

Also, This is a "Discussion" for the models. Just because someone from the METO say something is wrong, doesn't mean we shouldn't discuss it.

This is why we have so many models. They are there to get a "bigger" picture from multiple sources. Looking at trends and how "All" models behave is the only way to get an accurate idea.

I do agree that people can indeed be a bit negative however you need to ride the roller-coaster that is N-W in the winter.

Edited December 4, 2012 by Lynxus

[IDO]

Ian ferguson is saying the actual pro forecasters at the met office are favouring the ec model output of an easterly flow rather than the mogreps model which prefers a southerly flow but a strong signal of a blocking high is expected to develop anyway.after the weekend

So the negativity in this forum today is puzzling and a little silly; dont people actually read what one of the met forcasters is posting in this forum, unless people think the pro forecasters at the met haven,t a clue what will happen, I think I know who I would believe more TBH

Read what was said: "The EC solution has been favoured at the moment, with slightly more support, but with the caveat of occasional frontal incursions into at least in W’ern parts of the UK."

Not a ringing endorsement. I have never seen so many get out clauses (underlined). That's not Mr. Fergusson or the MO fault; there is high uncertainty. Yesterday 70% (approx) support for an Easterly of some sort, now nearer 50%. The trend isn't proved yet, but if that continues I suspect tomorrow they may change their views.

My opinion is that if the pros are unsure, then we just have to wait and see. 48 hours and we should know if the second bite of the cherry is missed. I am sure another chance will fall after mid month.

Edited December 4, 2012 by i'm dreaming of...

[Catacol]

There are many experienced forecasters here who do not work for them. however they probably could do if they wanted to.

Eh? I'm not so sure about that... at least in a senior forecasting capacity. I cant vouch for the qualifications of everyone who posts on here, but I doubt that "many" would make it onto the MetO team. I consistently find myself a little frustrated at the conservative language of the Met, but having scrutinised them for many years as my weather interest grew I must admit they do a very good job in the range up to 15 days. The fact that IanF has posted on here recently that they almost dont bother beyond 15 days is a little surprising, but probably about as good a piece of evidence as you'll ever get that microclimate forecasting is a fools game beyond that range and so why bother? We all love to see our favourite weather scenarios in the fantasy island tea leaves, but often they come to nought.

I think IanF's post earlier about the embryonic state of science, and in this case of long range forecasting, is a very good one. I'll bet there are plenty down at Exeter who have a secret passion for the long range stuff, even if the terms of their job description anchor them to the more near term realities of working for UK plc. For now the long range stuff can only be about trends and teleconnections - maybe it will never become more than that because the variables are so complex - but in my scanning of the internet GP is about as good as I have found and so I am maintaining my faith that this winter will be cold. Dabbling in the 7 - 10 day range is about all I can manage personally.

As to the current outllook as we wait for the 12z I was just musing as to how many of the really great historical cold spells had much to do with the first half of December. The odd cold snap - yes. 2010 got cold early but down here in the SW it didnt really kick in until near the end of the school term... very much the second half. I think the pattern and background signals look very good, at least to my amateur eye... and historically cold does not entrench itself in this part of the world until we hit the second half of December and sometimes later. I honestly think this is the best setup I can remember in my 9 years of weather addiction in terms of cold, and that would include 2010 because the strat signals began quite early to point to the vortex firing up in January so that spell rather flattered the rest of winter. This time around I can see 6 - 8 weeks of wonderful potential with the second half of Feb still up in the air.

I remain excited. I am not ashamed to admit that I love to see snow fall, rather rare on the Somerset/Devon border and I am really quite confident that I will see it this season. In 2010 most of the damned stuff fell overnight while I was asleep - sod's law that - so this year I hope for daylight snow!

And just to make sure I appease the mods and keep this on tack, here is yet another wonderful FI ensemble chart showing easterlies and battleground potential. This kind of chart is as good as it gets in the UK most of the time!

Edited December 4, 2012 by Catacol_Highlander

[Frosty.]

It just shows how the gfs can go from hero to zero in less than 24 hours, what will the 12z do?

GFS 00z still looked good for the north to have a cold blast next week but less cold uppers for the south, at least the ecm is still on track but things are looking a lot dodgier today than they have in the recent days, would be nice if we could get cross model agreement instead of 1 saying yes and 2 saying no etc.

[phil nw.]

I think it`s time for a new thread for the 12s so locking this shortly folks.

[kumquat]

I'm pretty sure Ian works for the BBC and not the MO.

[southbank]

Be interesting to see how the Euro models & GFS develop between T+ 96 to T+144 and what variations we see.

I cant help feeling that we may develop a Feb 2012 type easterly where the UK was just a tad to far on the fringes to get anything meaningful with milder inclusions into the SW

But got to admit despite that looking at the NH profile currently is great viewing and if it doesnt end in a 91/87 blast at least it will be festive !!

Edited December 4, 2012 by southbank

[phil nw.]

Locking this now-new thread here.