The hunt for cold - Model discussion (late November)

[frosty ground]

Amazing what a wedge of high pressure can do, low heading north but maybe to much momentum in the atlantic atm

[Methuselah]

2 minutes ago, AppleUK 123 said:

We haven't vanished at all, there really isn't anything to say no as the outcome is becoming ever clearer. I don't think people can say there is a new 'trend' just by looking at one model run from one particular model. The ICON 12Z could simply revert back to the ICON 0Z. There is currently no consistent trend.

Agreed, Apple...Given this, at T+117, I'd still favour an Atlantic incursion, of some kind. But to what extent and for how long?

[frosty ground]

Unlike the ICON we don't have the jet pointing back towards the UK from the north east.

 

[SMU]

The GFS 06z makes a swing to the ICON by holding the continental air in situ for longer & does indeed allign better than the 00z - however the halfway house just does delay inevitable movement of the altantic-

The 12zs would need to continue to move the atlantic west as well as the jet backing SW through scandi to create any meaningful change...

Edited November 22, 2018 by Steve Murr

[Nick F]

The block to the north of the UK this weekend sinks SE into continental Europe on most model output this morning, allowing the Atlantic low pressure system to gain traction by Wednesday, bringing milder, wet and windy conditions. 00z UKMO below, used to illustrate this:

However, as some have already remarked about, 06z ICON keeps the high held up just to our NE centred over Norway, thanks to deep cold pooling going around the eastern periphery of the high from the arctic and down into continental Europe, lowering heights and pressure and stopping the high from sinking:

However, I don't think we should get our hopes up too much with one model as it shows the 'better' outcome for coldies, even if it did well with the late Feb/early March cold spell, more runs needed with support from other models to back up this idea.

However, by 1st Dec there is growing uncertainty over pressure patterns, as the 00z EC mslp spread chart shows below

 

Edited November 22, 2018 by Nick F

[Methuselah]

Though looking bleak, in the medium-term, who know's the eventual outcome? It's all Shannon's fault!

Edited November 22, 2018 by Ed Stone

[Yarmy]

11 minutes ago, dixonoid said:

Omg!! I do believe the hunt for cold is over, in my freezer there was ice everywhere,on a serious note, this year has been controlled by high pressure one way or another, after the strat warming earlier in the year, the weather hasn't been the same, no constant attacks from low pressure from the Atlantic, so the odds are, if we get the blocking high in the right position I feel this winter is going to be very cold and I looks like mainly coming from the east. With the PV allover the place, not allowing a strong jet, which produces the low pressure conveyer and any future strat warming are just going to play further unpredictable havock with our weather, warmer sst's after the summer will help with the North sea snow Machine when a proper easterly sets up

 

 

 

I've seen a few people saying this, but it makes no sense. An SSW is just a response to a large scale planetary wave propagating upwards from the troposphere. They happen every couple of years or so.

Anyway, the 6Zs continue the theme of deflecting the worst of the Atlantic away to our NW so thankfully not wet (for most), but not very interesting either in terms of a hunt for cold. The FI search for renewed amplification begins in earnest. 

 

[Flash bang flash bang etc]

5 minutes ago, Ed Stone said:

Though looking bleak, in the medium-term, who know's the eventual outcome? It's all Shannon's fault!

I don’t see what Michael Shannon’s acting has to do with any of this?  

[frosty ground]

The GFS 06z like the 0z run gets everything past the Meridia.

[swfc]

The gulf between gfs and ecm this morning at day 10 is quite staggering imo.The mobility theme west to east looks to be on the up but who knows???

[ICE COLD]

Isn’t this quite a significant warming around day 10 on the gfs 6z ? 

[bluearmy]

6 minutes ago, ICE COLD said:

Isn’t this quite a significant warming around day 10 on the gfs 6z ? 

Yes - we are due a wave 1 displacement of the strat vortex towards the eurAsian side of the NH  by the end week 2 ..... what happens thereafter .............

[SMU]

Yes - & the GFS ENS 00z today paint a significant downturn in the upper zonal wind at a speed that is alligned to a reversal in december-

Of note in the 06z ENS there are a few more runs that bring the deep cold further west around 120-144- more than 00z but not a significant number overall-

That said there is a trend there- one that we want which lifts the low further NW & allows energy to trickle underneath-

The run that best fits the Icon 06z is PTB 12 which at 120 looks line this at 144 & produces a snow event 156-168

 

Interesting times...

[frosty ground]

Run 9 for the win, but the reality is these runs are few and far between.

Run 7 is a classic with a front getting into western UK turning to snow then being pushed back, 


 

Edited November 22, 2018 by frosty ground

[Methuselah]

Not sure whether I'd call the GFS's suggestion of a Greenland-Atlantic ridge (on day 15!) a trend... but I guess it's a start? That said, the European cold block's not progged to go 'poof', until around the middle of next week, either. A lot can happen, in six days!

Baby steps, until mid-December?

 

Edited November 22, 2018 by Ed Stone

[Iceaxecrampon]

06z

LP to watch for Tues next week (December!) 

Crosses Alba

Opens the Arctic pipeline

Result?

First real ppn shot for N altitudes.

[Bruegelian]

Somebody here said that the BBC monthly forecast is quite bullish about mild SW winds early-mid Dec which is interesting in a way, although not good news for most of us. However latest JMA monthly for this period seems to have some HLB going on: 

 

Interesting (though somewhat worrying) what Crewe Cold said about the long range models going for cold UK winter being predicated on a SSW in mid-late Dec, and that without it HLB will be difficult to achieve. Fingers crossed it does happen !

[Nick L]

Please keep personal conversations to PM, cheers.

[Nick F]

Looking at the EPS clusters, seems to be decent support (circa 45% of members) for an upper ridge to build over Scandi by day 10, with a greater number still of ens members suggesting the Atlantic troughing making little headway east past the UK, though not necessarily building a high over Scandi. So, for now, think we may need to look east for the chance of deep cold.

[Weegaz]

FI stuff, but as long as charts like this keep showing I will be an avid follower, a very amateurish one, of this forum for the prospects of winter to come

[Methuselah]

8 minutes ago, Weegaz said:

FI stuff, but as long as charts like this keep showing I will be an avid follower, a very amateurish one, of this forum for the prospects of winter to come

It's good to see that we have multiple options open to us: from the east, northeast, north; better by far than in all those years when the only cold there was was stuck over Greenland, with no way out?

Edited November 22, 2018 by Ed Stone

[Summer Sun]

Maybe a very slight recovery in temps for some over the weekend but it looks like we'll see another burst of chiller air early next week before winds eventually swing around to a milder direction

[Weegaz]

30 minutes ago, Ed Stone said:

It's good to see that we have multiple options open to us: from the east, northeast, north; better by far than in all those years when the only cold there was was stuck over Greenland, with no way out?

A dog with no tail has nothing to chase, hopefully we can catch the tail

[John Badrick]

2 hours ago, Iceaxecrampon said:

06z

LP to watch for Tues next week (December!) 

Crosses Alba

Opens the Arctic pipeline

Result?

First real ppn shot for N altitudes.

it's still November next Tuesday. we are very much still autumn watch!!

[Chesil View]

The main thing in the medium range is the rebuilding of a block towards Scandinavia around about day 10. 

8 of the next ten days are in November.

So to me that looks like a good way to start meteorological winter