Model output discussion - 1st December onwards

[mountain shadow]

4 hours ago, Neiller22 said:

One post says cold and snow.  Another says cold and rain! How will we ever learn on here with such contrasting views! At least it's all heading in right direction. 

At this range it's impossible to say and with Atlantic air mixing with contintenal air, you can have snow in one place where ten miles down the road it's rain. It all depends where the boundary is.

Generally the further North and East the better though.

[The PIT]

7 minutes ago, chris55 said:

We are not far off from something rather good. The charts are full of all the ingredients we crave for a good snowy spell in the UK. Both ECM and UkMO at 144 are a hares breath (in terms of the bigger picture) away from delivering a perfect storm, as the trough disrupts coming up against the high to our north and east. All we need is a slight correction south and west with a slightly more elongated trough and we are in business.

I know as they say " a miss is as good as a mile" but considering December this potential hit or miss is certainly worth keeping a close eye on!

ECM 144 trough approaching, a little to round at this point but does disrupt at 168

UKMO 144 better negative tilt at this stage than ECM id hazard to say UKMO 168 would be worth a look lol

 

 

Yup you're right but the overall model drift is to the wrong side of average. My suggestion to all is not to get carried away until cold is shown at T96 yup the only standard bearer and it still rings true today. We had a lot of ramping the other day and then the old noose job the next morning. Stay calm folks and keep the whiskey handy and barrel if it works out right.

[Tim Brawn]

When these charts are within 96+ might start to believe it , the MET seem very good on predicting the incoming storms of late at about 5 days out so that seems to be the real limit of accurate forecasting .     I'm working 12 hrs on 2nd and 2rd of Jan and on the road at 5.30AM for the next week so will be in a good postion to see any whitestuff that does fall

 

[The Enforcer]

On 27/12/2015 at 7:46 PM, The Enforcer said:

What might the current ECM T+240 look like by the time it reaches T+168?

Now at T+216:

Better or worse? I certainly don't like the appearance of that mild sector approaching the south-west, prompting an early *Mild Sector Alert*.

Edited December 28, 2015 by The Enforcer

[Cheshire Freeze]

4 minutes ago, Cheese Rice said:

I think it could be a case of close but no cigar in the south, further north as the colder air digs in we should see some frontal snowfall from a slider low.

ECM- Midlands northwards and I suspect we're talking widespread 6 inches, probably up to a foot of the stuff by end of play across parts of Scotland. A very snowy day 8&9.

[Bullseye]

With the doubt over whether the UK will join the party and get some cold/snow, wouldn't it be possible to look at previous times we have been in this situation and see how it unfolded? 

[mountsbaysnow]

As a novice and newbie where do we stand in the far southwest or is it a tad obvious:-S

 

[Mark Neal.]

6 minutes ago, Bullseye said:

With the doubt over whether the UK will join the party and get some cold/snow, wouldn't it be possible to look at previous times we have been in this situation and see how it unfolded? 

'North of the M4 myth!'  

@mountsbaysnow- You want the pattern further west, with colder air in place, would bring places further South and West into play for wintry conditions. 

Edited December 28, 2015 by Mark N

[Cheshire Freeze]

6 minutes ago, The Enforcer said:

Now at T+216:

Better or worse? I certainly don't like the appearance of that mild sector approaching the south-west, prompting an early *Mild Sector Alert*.

I would think the mild sector would occlude in that scenario.

[Mucka]

10 minutes ago, Bullseye said:

With the doubt over whether the UK will join the party and get some cold/snow, wouldn't it be possible to look at previous times we have been in this situation and see how it unfolded? 

That is the problem but also the beauty of the unpredictable nature of the weather, no two situations are ever the same.

For example all the models have the almost exact same starting data and positions yet the outcomes vary widely in terms of the weather we get locally so you can imagine that looking at situations that are different, with different starting data and different background signals, would not be helpful for predicting the outcome though it is of course interesting to compare and speculate.

 

Edited December 28, 2015 by Mucka

[The Enforcer]

7 minutes ago, CreweCold said:

I would think the mild sector would occlude in that scenario.

That's what I was told during last winter's cold spell, but there was only one overnight period when mild sectors didn't raise the wet bulb temperatures above the threshold for settling snow.

Edited December 28, 2015 by The Enforcer

[SMU]

Unanamous support for the slider 

scenario on the 192 ECM mean

watch for  significant temp drop off ( finally ) in the ensemble suite....

s

[Mucka]

Just now, THE CHOSEN ONE said:

Unanamous support for the slider 

scenario on the 192 ECM mean

watch for  significant temp drop off ( finally ) in the ensemble suite....

s

I think that is probably the  best chart of the day.

[fergieweather]

7 minutes ago, mountsbaysnow said:

As a novice and newbie where do we stand in the far southwest or is it a tad obvious:-S

 

No: nil obvious, because it's light years away meteorologically. If you took EC snow cover diagnostics literally (and we don't... at that range, most certainly) it's evidently an uplands gig Midlands-northwards with higher probability; mixed fortunes to S. The particular beauty of my region is how frequently I can use M4 as a delineation in weather fortunes of all varieties (see attached...!).

EC-ENS arriving now. That'll give us another pointer in this debacle looking to early Jan.

[helen47]

2 minutes ago, THE CHOSEN ONE said:

Unanamous support for the slider 

scenario on the 192 ECM mean

watch for  significant temp drop off ( finally ) in the ensemble suite....

s

GAME ON

[Daniel*]

There seems to be further unneeded rain in this coming week late Tuesday into Wednesday out of Storm Frank mention of 'localised' 140mm falling on saturated ground on ITV national forecast, for those that do not need it!

Next week there's not much in it between an extremely wet/very snowy picture for northwest England with Atlantic rearing its horns to cold air to the east. All in all v. exciting markedly less so for the flood stricken souls, who'll have to endure more flooding, the best model output since 2013. Even if we do not get much out of it nationwide - with vortex getting a beating more swoops will inevitably come.

Scotland & north of England parts of Midlands, looks likely to see a winter blast at least. South of the M4 I'm not seeing much out of this so far, more runs needed as always. Current 'false dawn' will provide a huge shock to the system. I have felt compelled to tell my friends & family of this 'change' but I've kept my mouth shut. 

. 

Edited December 28, 2015 by Daniel*
Spelling

[SMU]

Updated t2ms

today & yesterday

S

[Lakigigar]

[northwestsnow]

2 minutes ago, Mucka said:

I think that is probably the  best chart of the day.

Yipppppeeeee winter here we come you have been missed 

[Mark Neal.]

2 minutes ago, THE CHOSEN ONE said:

Updated t2ms

today & yesterday

S

Quick Summary- On the fall..

[bluearmy]

The extended ens have been very strong on the renewed push off the Atlantic around the 7th Jan at a latitude which cuts straight through the UK ( as per the 12z ECM op I suppose)

The updated ECM ens continue this and if anything, thanks to a mean ridge drifting be into s Iberia, they are not looking so good for this system to disrupt at all. if you wanted me to make a call I would say that this upcoming period sees a decent opportunity for snow cover, (the higher and further ne the better ) and then the Atlantic comes back through. all the while, polar blocking expands to create better chances for countrywide wintry conditions mid jan onwards. 

[snowking]

What I referred to yesterday regarding the higher resolution runs (i.e. Det & Control) usually being the ones to watch when you have such a delicate balance of energy split is more important than ever now to bear in mind. We should not be ignoring the 50% or so of the ECM ensemble suite which does not go for enough of an undercut to be of benefit to the UK by any means, but when the two highest resolution runs have been in tandem for such a period of time now more emphasis should perhaps be placed on these runs for now vs. the suite as a whole. The moment that changes, it might be time to be concerned (if cold is what you are looking for).

The situation though really is rather knife-edge even at this stage. For example taking a look at the ensemble output for Aberdeen looks rather impressive at the 850mb level..taking a look at it for Reading not only is the spread of solutions far higher but the uppers are averaging around -3c, with the Det and Control providing a fairly good median indication.

With all of this still looking at a scenario over a week away, I'd continue to urge caution for now.

SK

Edited December 28, 2015 by snowking

[MPG]

41 minutes ago, Neiller22 said:

One post says cold and snow.  Another says cold and rain! How will we ever learn on here with such contrasting views! At least it's all heading in right direction. 

And where's knocker? Need those westerly anomolies to keep our feet on the ground!

[radiohead]

2 minutes ago, snowking said:

What I referred to yesterday regarding the higher resolution runs (i.e. Det & Control) usually being the ones to watch when you have such a delicate balance of energy split is more important than ever now to bear in mind. We should not be ignoring the 50% or so of the ECM ensemble suite which does not go for enough of an undercut to be of benefit to the UK by any means, but when the two highest resolution runs have been in tandem for such a period of time now more emphasis should perhaps be placed on these runs for now vs. the suite as a whole. The moment that changes, it might be time to be concerned (if cold is what you are looking for).

The situation really is rather knife-edge even at this stage though. For example taking a look at the ensemble output for Aberdeen looks rather impressive at the 850mb level..taking a look at it for Reading not only is the spread of solutions far higher but the uppers are averaging around -3c, with the Det and Control providing a fairly good median indication.

With all of this still looking at a scenario over a week away, I'd continue to urge caution for now.

SK

Hi SK, just a minor point, but the control isn't a higher resolution run. It takes the same starting conditions as the Det however it is run at the same lower resolution as the ensemble suite.

Edited December 28, 2015 by radiohead

[The Enforcer]

4 minutes ago, MPG said:

And where's knocker? Need those westerly anomolies to keep our feet on the ground!

Exhausted his supply of red ink on those recent outputs.