Model Output Discussion 18th Nov.2013-12z onwards.

[Skeggy Winter Storm]

Absolute stonker of a Northerly in FI.

Thats some Northerly brrrrrrrr straight from the Artic

[radiohead]

A Frosty special.

 

[SMU]

http://www.wetterzentrale.de/pics/Rtavn24017.png

 

Chilly for max temps in Dec- .....

 

S

[Mucka]

If it wasn't for the shortwave spoiler popping up just E£st of Greenland at 240h we may have even got an Easterly out of it in deep FI, all academic I know.

 

 

Edited November 27, 2013 by Mucka

[East_England_Stormchaser91]

Thats some Northerly brrrrrrrr straight from the Artic

That would feel absolutely bitter. Liking how an Easterly then tries to make itself present against the Atlantic, classic battleground scenario setup. This is when the model watching becomes strongly addictive!

[Cloud 10]

The ultimate seal of approval for the 18z. 

 

[karlos1983]

Incredible pub run, I almost don't want to look in the morning, I'll be amazed if it still looks like that on the 0z, but here's to hoping!

Would be dry in my location as is usually the case with Northerly/north westerlies, but it would feel raw with some penetrating frosts I'd imagine

[BLAST FROM THE PAST]

well as most things have been said i,ll go into deep fi. T384 ladies and gents is a set up for the Russian hp to back west and a prolonged freeze. The run smells heavily of a certain winter.

 

on that note and back on terra firma...nice 18z run but is the delay of cold shot a good thing or a build up to 11th hr drama!?

 

 

 

 

bftp

[bluearmy]

Really? Sub 510 dam from a northerly in early december! Seriously? Oh, hang on - its the 18z. if snowballz is right then the 'pub run' is undeserved of its name - yet i dont recall the other runs producing such extreme output in general.

[Cheshire Freeze]

Really? Sub 510 dam from a northerly in early december! Seriously? Oh, hang on - its the 18z. if snowballz is right then the 'pub run' is undeserved of its name - yet i dont recall the other runs producing such extreme output in general.

 

It came into the far N of Scotland on the 12z run

 

[John Cox]

Eight days out. I will take this gladly... Considering 7 days is my normal accuracy max time. I know this is in my FI timescale

 

[kate1]

I really know nothing - but have been here in the run-up to winter for a couple of years now - but I just wanted to say over the last few days there have been some really helpful, well-informed and factual posts which have hugely helped my understanding. Off topic I guess, but thanks - and it's exciting to know winter is (hopefully) on its way, albeit slowly for us in the SE - but much more optimistic than a week ago!

[bluearmy]

It came into the far N of Scotland on the 12z run

 

I dont have a problem with the far north of scotland crewe. Milton keynes is another matter entirely!

The london ecm ens are better than expected with plenty of cold clustering remaining out to two weeks. Suspect they must, like yesterday, reflect a stagnant or gentle continental feed into se england. On the flip side, big spread of average to mild members now showing.

[Mucka]

ECM london ensembles

 

[draztik]

Looking at the 18z GFS at the end of its run, its hard not to note the cool uppers present over the UK. Interestingly, the ecm ensemble for day 15, show cool uppers in the Atlantic pushing east again, after a couple of days of average/slightly above - which is also indicated by the current gfs run.

Edited November 27, 2013 by draztik

[nick sussex]

Interesting GFS 18hrs run which delivers a northerly then throws in a spoiler shortwave to stop this thread from imploding as that scuppers a possible easterly.

 

The ECM and GFS are similar in terms of where they think the PV might go in the latter stages but earlier we see some marked differences upstream over Arctic Canada which IMO could prove important in terms of the cold evolution.

 

So you sort of get two similar outcomes but the ECM is more nerve shredding , the GFS looks the cleaner evolution as it phases that vorticity running west with a shortwave running east across the USA, you can see how they deal differently with high pressure over the eastern USA because of this.

 

I don't like the way the ECM finally gets to some interest, of course its 240hrs has real potential especially if the PV moves west to Canada and meets amplification upstream.

 

These are the respective ECM 168hrs from the 12hrs run and the GFS 18hrs to 162hrs, which do you prefer?

 

ECM

 

 

 

GFS

 

 

 

[Mucka]

18z ensembles a real mixed bag,

 

 

The control run was  poor for cold

Edited November 27, 2013 by Mucka

[Dancerwithwings]

Yes maybe a mixed bag, But the 18z operational was the better out of all the members put together, I'm H a p p y

Edited November 27, 2013 by Dancerwithwings

[Mucka]

18z ensembles central England

 

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=254&y=96

 

Flicking through the charts just the smallest hint of some of the members wanting to try and bring in an Easterly in deep FI but let's get our Northerly nailed before worrying about what happens next too much.

[Captain Shortwave]

ECM london ensembles

 

Huge scatter, could have anything from ice days to double figure maxima in there.

Well aside from outlier solutions I guess we have 3 possible outcomes.

1. Low pressure of the East coast of the states deepens and tracks north east flattening the Atlantic ridge - Game over solution as the polar vortex moves across the pole and pretty much a default pattern establishes (unsettled/drier areas up for grabs but the pattern is average to mild)

2. We get some form of northerly toppler which lasts a couple of days, perhaps longer before heights build across the UK, given the polar profile for week 2 onwards, we would probably return to a westerly pattern but it's too far out to even consider the specifics.

3. We get a deep trough over the states which in turn amplifies the downstream pattern, the low bringing the northerly gets cut off over Europe with the Atlantic and rapidly developing Russian/Siberian high link up sending us into a potential long period of Easterly winds with low pressure feeding off the Eastern seaboard down into Iberia, classic frigid set up.

So nice range of solutions but the 3 main solutions to look out for (could see some in-between solutions not mentioned but the picture is there I think)

As Mucka above says, lets get the Northerly nailed first because if we don't get that then any cold further down the line is sunk quicker than the Titanic.

Edited November 27, 2013 by Captain shortwave

[Mucka]

GFS 00z analysis.

 

Well if the GFS 00z is to be believed we are relying on the timing and rapid cyclogenesis of a shortwave to save the day since the Azores high wants to ridge in strongly to the SW as the initial trough doesn't get far enough South (chicken and egg there)

 

144h we see high pressure still in control over the UK and the shortwave just appearing on its Western flank. Things don't look great at this point.

 

 

By 168 we can see the high has ridged East but is being sunk by the low that has developed from our shortwave at 144h

 

 

By 192h we can see we have displaced the high enough to start bringing in the colder air at last

 

 

Thereafter we have a nice jet profile and the LP on the Western flank of our ridge moves South rather than NE which is a nice new development and the trough to our East continues to sink. which is what we want.

 

 

However we can see there is still remaining vortex energy West of  Greenland spawning new areas of LP that put pressure on the ridge but we also have the Russian high coming into play to the East. I described this scenario in some detail yesterday and many others have talked about a possible link up with our ridge as a way to prolong any cold - worth keeping an eye on but our Northerly and especially such a pronounced and strong ridge is in no way secure yet thus, as has been mentioned by CS that analysis will be totally redundant if we don't get that.

 

 

Overall a very encouraging run but I am not ramping it (I'm sure others will, the SE never gets out of the cold uppers and a prolonged cold pattern is set up) as most of the eye candy is developed in FI and having to rely on that shortwave completely won't be good for the nerves, there are so many ways for it to go wrong without worrying about sods law.

I would stiil like to see more amplification earlier and that damn high to our SW clear off, the AH ridging back in across the SW has ruined many a potential cold spell.

Edited November 28, 2013 by Mucka

[Mucka]

UKMO 00z

 

Straight to the 144h chart here and a quick comparison with GFS.

 

 

We see reasonable cross model agreement here and in some ways the UKMO looks better in that it is a little more amplified and displacing the high better so potentially would bring the cold in quicker. It has the same trigger shortwave as GFS with only small differences but of course we can't know the track and development of that shortwave as we don't get to see charts past 144h on the UKMO - very frustrating in this instance!

Let's assume it is similar to GFS and we go on to revel in a Winter wonderland - let's say a deep Northerly lasting 4 days followed by a brief Northeasterly as the ridge slowly arches across to Scandi and links up with heights there bringing in a 3 day Easterly before the high retrogresses to Greenland giving a week of subzero Northeasterly and snow drifts. Sound good? I'm sure some would still be complaining though 

 

Tonight's UKMO will definitely be interesting viewing

 

GEM 00z  shows us how things can go wrong if the shortwave isn't on our side, here it is at 144h

 

 

168h and 192h

 

 

As you can see the cold air never gets across the UK.

 

GFS ensembles

 

Not particularly encouraging and I'm being kind. The control gives us a 2 day toppler and that is better than many while the Op was a massive cold outlier in FI. Enjoy those charts it may be some time before we see them again, unless, unless the Op has it nailed against the odds. 

 

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=254&y=89

Edited November 28, 2013 by Mucka

[Great Plum]

Full of optimism this morning after reading Mucka's excellent summary of the GFS this morning, I had a look at the ensembles...

http://www.wetterzentrale.de/pics/MT8_London_ens.png

Oh dear... A clear outlier if ever I saw one! James Madden has obviously taken reigns of the computer... However, my 10 years (when did that happen?) of me being on here has told me that if the op run goes off on one, see the next few GFS runs to see if there's any support before completely dismissing it!

I'll be clear, it is a rank outsider at the moment, especially with the 'vortex that's all vortexy' (thank you Lorenzo - it's the phrase that keeps giving...) nevertheless, let's enjoy the charts!

[Mucka]

ECM 168 looks fine regarding the initial trough displacing the high, will we get a good ridge behind and decent cold or a quick toppler?

 

 

Well, half and half, still a toppler but real Arctic blast and improved on last nights output.- potential there.

 

 

If you just took the Operational output of the big three then this mornings output would be very encouraging.

Edited November 28, 2013 by Mucka

[Ali1977]

Looking at this mornings charts, country wide snow next Fri/Sat still looks a possibility, with possible blizzards in strong Northerly winds. I think anyway!!!!