Model Output Discussion 12z 04/12/2012

[Jupiters Winter]

Matt Hugo thoughts on Twitter are as many i would say.

@MattHugo81: The 12z ECMWF model looks a distinctly cold run and for now should be dismissed particularly by 216/240hrs. Still a cold E'ly is now 'on'!

[mcweather]

Way back before tonights ECM sent this place into meltdown ( or should that be freeze up mode). I remember Ian Fergusson posting that the UKMO were very interested to see what tonights ECM would deliver. Could this be because despite their normally cautious approach that their longer term ensembles have been picking up on the same outcome as well. Just a thought.

[SnowObsessor90]

Que the models doing a full 360 degree turn and showing Bartlett highs galore tomorrow

[Absolute Zero]

all this talk of "perfection" "as good as it gets" along with "expect downgrades" "we know it won't happen" etc. etc. etc.

what if?...... it upgrades............

We are all doomed, people across the country with their tongues stuck to lamp posts !

Edited December 5, 2012 by Absolute Zero

[karlos1983]

all this talk of "perfection" "as good as it gets" along with "expect downgrades" "we know it won't happen" etc. etc. etc.

what if?...... it upgrades............

We start wishing we had coats as thick as chewbacca

[NorthNorfolkWeather]

Que the models doing a full 360 degree turn and showing Bartlett highs galore tomorrow

You man, what are you trying to do provoke mass suicides?

CAn someone point me at the archives so I can compare 1987 to the current charts?

[Hammer]

Ian F won't be posting soon, he dropped his coffee on his keyboard following ECM.

[Mark Bayley]

I wonder what the pub run will be like, if anythings going to beat that ECM run it will be that!

[Jason M]

Oddly the gradual increase in intensity being shown might be working in our favour. Last feb it seemed to me that the biggest problem was actually the sheer depth of the cold. When 850s of -20 and below are involved that in itself can cause disturbances and cut off lows etc.

The fact that its early Dec and that the 850s are not so extreme might be helpful. That's not to say that the surface temps won't be xtreme given the fact were approaching the shortest day of the year.

Jason

[snowking]

I'm still shaking my head in disbelief to be honest, just when you think you've seen it all...

I think we would be wise to summarise things here as they stand

Yes to some form of easterly: GFS (+ens), JMA, ECMWF

Getting towards the same solution vs 24 hours previous: UKMO, GEM

Incidentally, that is the three best verifying 12z model runs saying yes to an easterly.

The extreme details can be left to dream over beyond +168, but importantly the ECMWF, the best verifying model in the last 10 years throughout, is showing us the setup of an easterly within 5 days. This isnt definitive yet, but we are talking 75%+ probability - though I must stress we must wait for ensembles tonight (75% probability derived from operational ECMWF, GFS and JMA, as well as GFS ENS) - IF the ECMWF ensembles remain as promising or become even more promising than those from 12z/0z, then that probability, for me, shoots up to around 80%

I concur with the thoughts of expect subtle downgrades at the present time. Whilst this doesnt mean we are removing the threat of some large snowfalls and very cold temperatures, the ECMWF is really extreme.

ECM ens awaited with great excitement

SK

Edited December 5, 2012 by snowking

[Froze were the Days]

Matt Hugo thoughts on Twitter are as many i would say.

@MattHugo81: The 12z ECMWF model looks a distinctly cold run and for now should be dismissed particularly by 216/240hrs. Still a cold E'ly is now 'on'!

What does he mean by dismissed? simply as it is in the low-res category?

[Snowy Easterlies]

Que the models doing a full 360 degree turn and showing Bartlett highs galore tomorrow

lol it won't flip to that tomorrow but by the weekend it it could, anyway great ECM

is the UKMO any good? it looks better than previous runs but GFS and ECM are better at T144

[BLAST FROM THE PAST]

As Jan / Feb 2012 has been mentioned and how it can go wrong I will post the difference on the runs ahead compared to then. Its at the point of the trigger LP.

Look at the heights around southern Greenland etc......low

Now look at GFS and within t100

ECM again heights in that area. What does this mean? Whenthe link up occurs there's no SW or LP attack from there and the block is held in place extending beyong UK and Ireland.....solid easterly in place and why I think the chances of Feb 12 repeat are low in comparison.....its all about the level of severity, not the easterly. Cold, V Cold or Bitterly cold.....time will tell.

UKMO is also moving in right direction too

BFTP

Edited December 5, 2012 by BLAST FROM THE PAST

[Geordiesnow]

I do think we need to urge some caution here and see how the shortwaves will behave first, the low sliding through the UK during the weekend is getting firmed up now and I don't see too many nasty surprises regarding that, its the area around Svalbard and perhaps the east Greenland sea I will be looking at. What we don't really want too see is the models firing up any lows around Svalbard which may try and push down on the high as that may collapse it quicker, this can often happen and we have seen in the past how easterlies try to turn into Northerlies and alot of a time don't actually turn out like that.

Its a massive high, but don't be fooled by that, because with the way the weather works, its can still topple into an unfavorable position but I do think some sort of high pressure will be over Scandi, question is, how far West it will head and shortwaves will play a part in that.

Some good runs, and even I'm at the stage where I am tense for the next run, whereas previously I thought its still a little too far out to really dwell on the charts. I think we are going have to accept a lack of a distinctive cold pool to start off with but upper air temps should be cold enough for bright convective weather, not sure at first they will be cold enough for snow, espcially for those members who live close to the east coast.

[ICETAB]

Question, would the ECM bring snow in the form of convective showers only or would there be fronts embedded in the flow? It is clear that the east is going to do well but what about the rest of the country? I know it's too early to know exactly where snow will fall; the question is based on tonight’s 12z

[Downburst]

the ECM is a very cold run, an idea of what "might" or "could" happen if the reality runs as predicted the week before, but it never does exactly that. Now there is a lot of support for it for sure and the signals point to a Scandi high so I do expect an easterly but that's all. Please please do not post downhearted posts is the next run shows a "downgrade" and remember FI is always 72 to 96 hours and what is written here will be forgotten about in 1 hour, so by tomorrow who knows what to expect.

[P-M]

All I will say is hats off to the peeps who said this period would be the change to colder conditions if this is the case. Some really knowledgeable people on her (GP, Chino, Steve M - the resident snowman and John Homes etc)

Like people have said stunning charts from this run - bring on the freezer I say - I am still learning re snowfall etc but temp wise looks like taking a nosedive in the right direction.... ;-))

[BLAST FROM THE PAST]

Why would it be better, if it were to come off, than Jan '87 if the uppers were around 5C colder back then?

The sheer scale and the westward extent of the easterlies and HP into Greenland, it would go on longer and be more sustained. Feb 86 longevity springs to mind. Combine the both and ....there we have it. But caution re severity/longevity must be heeded here folks.

BFTP

Edited December 5, 2012 by BLAST FROM THE PAST

[Dean E]

Nearly fell off my chair when I saw the ECM...

In my years of study and model watching, I've never seen such a beast of an outlook from the ECM. I remember looking at such historic models from the 60's and late 80s in my studies and this just goes right up there at the top. Something like this happening in today's modern world would be a massive challenge!

Obviously I'm ignoring everything +96hrs, but its something that the ECM never really dishes out.

A good evening overall

SM

[Timmytour]

Can I be another one to sound a note of caution? Despite some fantastic looking charts it can still all end up in a damp squib

Of course, it would feel like a referee's given a penalty against your team's goalkeeper for handball in the box, but who's to say that we don't end up with such a ref?

[CanadaAl]

To think, James Madden will certainly be filling his boots with these charts! haha

[chionomaniac]

The thing about the ECM tonight is that the evolution fits in perfectly with the teleconnective thoughts and stratospheric vortex positioning. Even though we know that nothing is nailed until it occurs weatherwise, there is a high chance of the type of easterly developing. From the moment that the forecasts showed the displacement of the strat PV to the Canadian sector and that these looked reliable, the height rises to the NE in some form or another looked a safe bet ( unlike the easterlies called earlier in the autumn).

However, we are now seeing in FI, the next chapter being modelled. That is the transfer of energy from the canadian sector to Siberia.

And of course if this occurs this is likely to prevent any Scandi block drifting east, whilst opening up the possibilities height rises to the NW that the Scand block will retrogress into whilst an undercut is still present.

And that is where I think the models will progress to - another natural progression of the existing pattern.

[ISAAC]

poor run from the ECM

.... if your no fan of becoming an eskimo (if thats how you spell it ? )

[P-M]

Can I be another one to sound a note of caution? Despite some fantastic looking charts it can still all end up in a damp squib

Of course, it would feel like a referee's given a penalty against your team's goalkeeper for handball in the box, but who's to say that we don't end up with such a ref?

With the background signals in place and blocking I would be surprised if this was a damp squib, saying that even a watered down version of tonight's ECM would suit me and a lot of other people just fine .....

[Jimmyh]

Firstly 922 users shows this is fairly epic proportions. The question is what at the moment showing as FI and what do we take as a reliable time frame. I myself have never seen charts like this