Model Output Discussion - cold spell to end Autumn

[Frosty.]

The good news is the Gfs 00z gets there in the end!!..BOOM...are you havin a laff Frosty

[Penrith Snow]

 Massive downgrade across the models but all as expected given the universal forecasts of a mild winter from nearly all the worlds seasonal models.

We have been here so many times before so I like many others were not drawn in by Stella charts beyond 144, why do the models do this every winter?

It seems like a period of anticyclonic gloom is on the cards with a slow moving UK high before this eventually fades away east allowing the Atlantic back in.

Familiar story.

Andy

[snowbunting]

Oh dear the ECM follows the GFS to the sin bin made  by snow lovers. Interesting that the GFS follows this evolution. I would imagine there will be changes one if which is the that the Northerly incursion may get to the North of Scotland and gets a good dumping of snow on it leading edge. The other is that the nasty low gets really deep and moves fast across the uk dragging much colder air behind it. 

 

Last thought... the Greenie ridging theory is far from being dead in the water. It has a quick/rapid genesis on the runs I have seen. 

I would be surprised to see a Northerly outbreak next week. Still a long way off. 

[draztik]

5 minutes ago, Penrith Snow said:

I like many others were not drawn in by Stella charts beyond 144

I think we need this type of humour on a morning like this. 

[Frosty.]

We still have this weeks potent northerly beast to look forward to..chin up coldies??..more of a meow than a roar

Edited November 28, 2017 by Frosty.

[Chesil View]

Just now, northwestsnow said:

Feels like there could be 99.9% of clusters showing a northerly and 0.1% showing a euro high +NAO and i know where my money would be !!!!

O well, we wait to see, gfs00z ends well at 384 hrs 

Well this time last year we had 100% ( all 51 ECM ensembles ) assuring us of easterly or northeasterly airflows only to be dropped the very next run.

Conclusion: unless its overwhelmingly conclusive atT48/72 then even the mighty ECM is to be taken with a very large pinch of salt.

just a few days ago we were being assured of low hieghts to our south over europe. mmmm

Things may yet change back again. So the models could I suppose be cut a bit of slack. After all we don't have a raging pv in place which probably throws a few spanners in the works.

Lets face it when we do have a raging pv ovet Greenland. None of us needs a computer model to know whats going to happen.

 

 

 

[Ali1977]

Maybe models should only run to day 6 as beyond that chocolate fireguard springs to mind - that said with this in mind they could swing back by tonight 

[Summer Sun]

ECM London ens shows it turning less cold into next week the 'coldest' day next week could be Thursday when the mean gets down to -1

[Had Worse]

1 minute ago, Ali1977 said:

Maybe models should only run to day 6 as beyond that chocolate fireguard springs to mind - that said with this in mind they could swing back by tonight 

Near enough the entire boards wishes.

I keep saying to myself that the weather will do what it wants and the models will try to best guess what is actually going on in our atmosphre. 

This stops me from reaching for the Prozac. 

[northwestsnow]

1 minute ago, Ali1977 said:

Maybe models should only run to day 6 as beyond that chocolate fireguard springs to mind - that said with this in mind they could swing back by tonight 

Only chocolate fireguard when they are suggesting cold Ali-

I did wonder about a flip back and then just dismissed the idea, it really doesn't work like that i'm afraid.

Undoubtedly the energy in the mid Atlantic now modelled at 120 prevents the link up of the mid Atlantic high into Greenland.

I wouldn't be at all suprised if we are staring down the barrel of a +NAO / Euro high combo pretty soon.

Obviously one hopes for colder episodes at some point but next week looks dead in the water.

 

[Weather Boy]

Right....

So, today we know that the models are definitely right.  Whereas yesterday, when they were showing cold, we may have thought that they were right, but we now know they definitely weren't.

That is illogical.  There is no reason to think that the models are any more likely to be right today than they were yesterday.

You don't need much experience of the models to see that, but it still seems that some are insistent on believing what they want to believe from a particular day's runs.

Nobody knows for sure what the weather will be like much after next weekend, including the models.

[bluearmy]

The failure of euro low heights by day ten now advertised on the eps - to be fair to the whole evolution its the Atlantic non cut off low preventing retrogression and no undercutting to support the ridge responsible (as it was at some point last winter ).  

There remains a spread on uppers supportive of the northerly so it’s not quite dead but the fat lady is on stage and her throat is cleared .......

[knocker]

1 minute ago, northwestsnow said:

Only chocolate fireguard when they are suggesting cold Ali-

I did wonder about a flip back and then just dismissed the idea, it really doesn't work like that i'm afraid.

Undoubtedly the energy in the mid Atlantic now modelled at 120 prevents the link up of the mid Atlantic high into Greenland.

I wouldn't be at all suprised if we are staring down the barrel of a +NAO / Euro high combo pretty soon.

Obviously one hopes for colder episodes at some point but next week looks dead in the water.

 

But that link could, repeat could, be reestablished with upstream amplification in the medium term.

[lassie23]

12 minutes ago, Frosty. said:

We still have this weeks potent northerly beast to look forward to..chin up coldies??..more of a meow than a roar

What northerly beast?

[northwestsnow]

1 minute ago, knocker said:

But that link could, repeat could, be reestablished with upstream amplification in the medium term.

It could i agree, but i think its fair to say its extremely unlikely.:)

[bluearmy]

Just now, knocker said:

But that link could, repeat could, be reestablished with upstream amplification in the medium term.

True enough knocks and this accelerated amplification was a surprise when it appeared - however, the assumption will be that any attempt at retrogression will be scuppered with small depressions in the Atlantic nearer the time

note to Crewe that the greeny/mid Atlantic upper ridge is there by day 10 but we look unlikely to be benefiting from it at that timescale 

[Kentish Snowman in Yorks]

So to sum up this mornings model runs then.....all the blocking all the promising outlook negative NAO AO QBO potential strat warming all dead in the water and winter is over?

Well if that's the case I am off to B&Q to beat the rush on barbeques!!  

[northwestsnow]

EC mean looks hideous.

Here comes the euro high/+NAO i was referencing...

[knocker]

2 minutes ago, bluearmy said:

True enough knocks and this accelerated amplification was a surprise when it appeared - however, the assumption will be that any attempt at retrogression will be scuppered with small depressions in the Atlantic nearer the time

note to Crewe that the greeny/mid Atlantic upper ridge is there by day 10 but we look unlikely to be benefiting from it at that timescale 

Indeed ba, always a balance between the energy from the eastern seaboard and the strength of the ridging.

[Day 10]

1 minute ago, Weather Boy said:

Right....

So, today we know that the models are definitely right.  Whereas yesterday, when they were showing cold, we may have thought that they were right, but we now know they definitely weren't.

That is illogical.  There is no reason to think that the models are any more likely to be right today than they were yesterday.

You don't need much experience of the models to see that, but it still seems that some are insistent on believing what they want to believe from a particular day's runs.

Nobody knows for sure what the weather will be like much after next weekend, including the models.

Good post.

Here are the 'big 3' at 144, they don't all agree (shock horror). I wouldn't bother looking past 144.

The other day I said put the champagne on ice until the UKMO fell into line with the other 2, well right now similar applies. The UKMO isn't in line with the other 2 and is now showing the better solution for coldies, so why should the other 2 be automatically correct now they aren't looking as good?

Let's hang fire on waving the white flag, plus Winter hasn't even started yet.

[bluearmy]

6 minutes ago, northwestsnow said:

EC mean looks hideous.

Here comes the euro high/+NAO i was referencing...

Hideous?  Really ? Three wave standing pattern hemispherically is never hideous at the beginning December 

fwiw, the model develops low euro heights straight afterwards though quite a flat jet  feeding into w Europe - if I were you with your latitude and height I would be getting interested ! 

[northwestsnow]

2 minutes ago, bluearmy said:

Hideous?  Really ? Three wave standing pattern hemispherically is never hideous at the beginning December 

fwiw, the model develops low euro heights straight afterwards though quite a flat jet  feeding into w Europe - if I were you with your latitude and height I would be getting interested ! 

 

Looks bad to me blue?

drat, keeps showing yesterdays, which as massively better than today!(at day 8 )

Edited November 28, 2017 by northwestsnow

[Nick F]

As I mentioned last night, the split flow over the N Atlantic isn’t doing any favours wrt to maintaining the N Atlantic block far enough north, increased energy going into the southern extension of the jet over the Atlantic comes with increased troughing between New Foundland and the Azores - which pushes the Mid-Atlantic ridge toward western Europe.

The reason for the split flow is the block currently over the Atlantic and a zonal flow upstream over N America which stretches back all the way to E Asia.

The flow over N America does amplify in the medium range, as the strong jet over E Asia relaxes to allow the flow to buckle downstream with NA west coast ridge and deepening east coast trough ... the hope for coldies is that this amplification translates downstream to build the N Atlantic block towards Greenland again, allowing another Nly reload. But there are no guarantees on this evolution, particularly if the trop PV over N Canada migrates low heights  further east over Greenland -which would mean the jet flattening out over the Atlantic rather than amplify. 

 

Edited November 28, 2017 by Nick F

[jvenge]

ECM EPS hint that it might be a little (i stress a little) premature to slash ones wrists this morning. Both the control and mean keep the UK below average temperatures for the next few weeks. The control in particular is quite cold after T240 for a few days. Although it has to be said that the signal from the mean looks a little weak after day 10 or so and one suspects there must be more than a few milder options in order for the mean to be so weak.

EPS 46 from yesterday is getting the UK toasty (and much of Europe) after day 15 or so. Not that I have much faith in that.

 

 

[Paul]

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