Model output discussion - The Hunt For Cold

[Summer Sun]

12z 7-day trend even colder than the 00z especially so in NE Scotland could be 7c to 10c below average in places

Edited October 22, 2018 by Summer Sun

[Brucie]

I share other people's fear on here that these amazing synoptics for cold have maybe come a bit too early...but you never know.  It has been a strange year for weather & something has definitely impacted upon the coupling up of the stratospheric and tropospheric vortex in recent years.

Looking at the charts, I can see there's a lot of Alaskan / Aleutian high pressure reaching right into the Arctic. Is this what we should be watching for in the next few weeks if we want a continued disruption of the polar vortex & a possibility of a canadian warming?

TIA

David, Northallerton

[nick sussex]

This mornings ECM op developed low pressure towards northern Italy , that’s what we want to see tonight . We don’t want the UKMO solution of the low towards Iberia , that solution won’t anchor the Scandi high in a favourable position and will allow milder air to work nw into Central Europe .

 

[Mike Poole]

Well that PV looks well mangled!

ECM at T168.

And here at T192:

Edited October 22, 2018 by Mike Poole

[northwestsnow]

That EC 168 would produce a snow fest for many if the 850s were a few notches lower!!

[Met4Cast]

Scandi High. Massive trough disruption. No Vortex in sight. Basically zero model drama or shortwave drama.

Bloody hell why is it only October.

[MR EXTREMES]

Absolutely interesting all models are interesting tonight.

ECM is nice looking them blobs of residual heights can be very stubborn.

I'm sure something brewing.

 

[MR EXTREMES]

I reckon the ECM 240 lining up for another northerly 

[nick sussex]

After the northerly a lot of uncertainty because of the interaction of low pressure to the west and low pressure to the south .

The ECM pulls a lot of milder air into Central Europe , there’s some quite decent cold pooling  over Scandi so the question is whether than can get pulled west and engage fronts .

What were not seeing is good trough disruption at the key timeframe and the models disagree with where low pressure sets up to the south . However that might change given the timeframes .

So could be a range of outcomes post the northerly , some more interesting than what’s currently on show.

 

[karlos1983]

Great chart at 168 by the ECM,

a tweak here and there and it’s a beauty! 

Some brutal cold for the time of year in Scandinavia 

 

[BlueHedgehog074]

15 minutes ago, Mike Poole said:

Well that PV looks well mangled!

ECM at T168.

And here at T192:

It’s almost like something out of a horror movie! But one with a happy ending where the good guy - the High Pressure and its ridges - defeats the bad guy - The Vortex!

[East_England_Stormchaser91]

1 hour ago, Summer Sun said:

12z 7-day trend even colder than the 00z especially so in NE Scotland could be 7c to 10c below average in places

A lot of similarities to 2010. More so to note the SE Europe warmth, I remember early November 2010, Cyprus and parts of Greece were still recording 27-28c maxes. This type of pattern will favour low pressure development in the Med and Central Europe, which is certainly better than a Eurotrash high, like October 2006 and 2011. 

[carinthian]

Unbelievable ? One of the longest draws out of deepest Africa ever ! Turn off the heating again ?

C

[nick sussex]

1 minute ago, carinthian said:

Unbelievable ? One of the longest draws out of deepest Africa ever ! Turn off the heating again ?

C

Yes just goes to show you can have a weak PV and still end up with everything in the wrong place ! Still a long way out so it might change nearer the time . 

[Kirkcaldy Weather]

P1 with a near split in the pv (what there is of a pv) 

P3 

P7 gets close to a boom chart with the blocking to the west of greenland/ canada forcing the cold to our side 

P18 the best of the bunch  

 

[Chesil View]

2 minutes ago, nick sussex said:

Yes just goes to show you can have a weak PV and still end up with everything in the wrong place ! Still a long way out so it might change nearer the time . 

Quite so Nick. Without that Genoa low in place nearly all potential Scandi highs just get flabby and sink away southeast. I,m not too bothered if the progged scandi high does go that way for now. I really don,t see the point of wonderful winter synoptics in the first half of November. If we get a repeat showing for something scandi like from say 20th Nov then that really would be interesting. For the moment however the phrase "flattering to deceive" comes to mind.

[carinthian]

16 minutes ago, nick sussex said:

Yes just goes to show you can have a weak PV and still end up with everything in the wrong place ! Still a long way out so it might change nearer the time . 

Hope so Nick. A big difference between GFS and ECM at 240t. Think at 144t , a cyclonic development is sure to form over NW Med along the strong baroclinic zone. UKMO movesit to Iberia, GFS moves it over the British Isles and ECM all over the place. So as you say a long way out and probably not determined post 144t how things will evolve but one things for sure a cold weekend for the UK.

C

Edited October 22, 2018 by carinthian

[Man With Beard]

33 minutes ago, MR EXTREMES said:

I reckon the ECM 240 lining up for another northerly 

I could swear it looks like a southerly to me and a possible return to the high teens in temperatures 

But pure la-la-land at the moment, the kind of synoptics coming up are the ones most likely to throw up unexpected model runs as early as D5. 

[Summer Sun]

ECM 12z is 2 extremes from the cold of the weekend and early next week to the potential for something a lot milder around Halloween

[MR EXTREMES]

4 minutes ago, Man With Beard said:

I could swear it looks like a southerly to me and a possible return to the high teens in temperatures 

But pure la-la-land at the moment, the kind of synoptics coming up are the ones most likely to throw up unexpected model runs as early as D5. 

Yes southerly with Bartlet heights.

Mind you not to bothered early days yet.

These charts in late November or December we would be very excited.

 

[BLAST FROM THE PAST]

27 minutes ago, carinthian said:

Unbelievable ? One of the longest draws out of deepest Africa ever ! Turn off the heating again ?

C

This is The LIA footprint in full glory.  The swing of extremes is incredible

 

BFTP

[Man With Beard]

4 minutes ago, MR EXTREMES said:

Yes southerly with Bartlet heights.

Mind you not to bothered early days yet.

These charts in late November or December we would be very excited.

 

In January, that Atlantic to Scandi High move could have triggered a widespread snow fest. I don't think I've ever seen this kind of move modelled as beautifully as it is being right now. 

[Mike Poole]

18 minutes ago, Broadmayne blizzard said:

Quite so Nick. Without that Genoa low in place nearly all potential Scandi highs just get flabby and sink away southeast. I,m not too bothered if the progged scandi high does go that way for now. I really don,t see the point of wonderful winter synoptics in the first half of November. If we get a repeat showing for something scandi like from say 20th Nov then that really would be interesting. For the moment however the phrase "flattering to deceive" comes to mind.

I agree to an extent.  What is important at this stage for 'jam tomorrow' is that the models continue to show the beaten-up shredded trop PV, a la ECM T168.  Whether that means a cold blast or warm southerlies for the UK at the moment is moot, as far as I'm concerned.  (My location may mean the difference between cold rain and mild sunshine, I know which I prefer - the stakes may be higher further north, I know!)

Total disconnect between the strat and trop vortexes at the moment, and modelled in the reliable. I've got a nervous eye on this as we move forward into November, as it is the thing that can make or scupper this front loaded winter idea...is it simplistic to boil it down to 3 possibilities?

1. Early strat warming aka Canadian warming, increasing likelihood of Dec cold.

2. Marmalised trop vortex holds off down welling from the strat - result possibly even increased likelihood of UK cold in Dec.

3. Strat vortex wins as of Dec 2016, game over.

I would really struggle to put probabilities against these at the moment, but I'll have a go and others can offer opinions: 1. 20%, 2. 55%, 3. 25%.

[Chesil View]

23 minutes ago, Mike Poole said:

I agree to an extent.  What is important at this stage for 'jam tomorrow' is that the models continue to show the beaten-up shredded trop PV, a la ECM T168.  Whether that means a cold blast or warm southerlies for the UK at the moment is moot, as far as I'm concerned.  (My location may mean the difference between cold rain and mild sunshine, I know which I prefer - the stakes may be higher further north, I know!)

Total disconnect between the strat and trop vortexes at the moment, and modelled in the reliable. I've got a nervous eye on this as we move forward into November, as it is the thing that can make or scupper this front loaded winter idea...is it simplistic to boil it down to 3 possibilities?

1. Early strat warming aka Canadian warming, increasing likelihood of Dec cold.

2. Marmalised trop vortex holds off down welling from the strat - result possibly even increased likelihood of UK cold in Dec.

3. Strat vortex wins as of Dec 2016, game over.

I would really struggle to put probabilities against these at the moment, but I'll have a go and others can offer opinions: 1. 20%, 2. 55%, 3. 25%.

Yes Mike I have a problem with the trop/strat disconnect too. Surely it would be a better harbinger for a cold winter if they were connected but in as much disarray as the trop appears to be at the moment. I just get the feeling that while it is only the trop vortex that is then the strat can suddenly decide to downwell and then as you say its 2016 all over again.

[Met4Cast]

23 minutes ago, Broadmayne blizzard said:

Yes Mike I have a problem with the trop/strat disconnect too. Surely it would be a better harbinger for a cold winter if they were connected but in as much disarray as the trop appears to be at the moment. I just get the feeling that while it is only the trop vortex that is then the strat can suddenly decide to downwell and then as you say its 2016 all over again.

I think downwelling is more likely mid-later winter as the +QBO begins to decend, at the moment we’re in a good position for the Strat/Trop to remain in the disconnect we’re currently seeing.

The current predicted patterns will only aid in that, if not put pressure on the Strat from below. I would like to see a Canadian warming just to further boost that but at the same time, SSW have ironically been known to re-juggle the atmosphere for the worse for our little island, so either one is a risk, but, that’s the UK weather for you.