Model output discussion - The Hunt For Cold

[shaky]

And on another positive note just checked the 12z ukmo 144 hour chart from yesterday and compared it to todays and theres an upgrade there aswell!!scandi high further west and no more sagging of the high towards the mediteranean today and cold air coming in from the east right around the perfectly rounded scandi high!!just brilliant!!

[Met4Cast]

Just to ground is back into reality for a moment, the ICON isn't amazing

Far too much energy around Southern Greenland/more of a Scandi/Euro high as opposed to a Scandi High as seen on the GFS.

[Jonathan Rhodri Roberts]

According to the long term CFS, after a colder than average December, Jan & Feb is average followed once again by a very cold March, personally I'd have liked to have seen that in Jan/first half of Feb as the days would still be quite short with a weak sun and cold sea temperatures giving southern & western coasts some snow too and not just the cold old rain/sleet but having said that, March delivered for us this year in South Wales, it was so unusual battling through blizzards during St Davids day celebrations 

Edited November 13, 2018 by Jonathan Rhodri Roberts

[BLAST FROM THE PAST]

1 hour ago, Nick L said:

Folks, I know we're taking a bit more of a laid back stance in this thread but a lot of posts at the moment really add nothing to the thread. I feel like we repeat this every winter, but posts like "eyes down, here comes the 12z" and just posting charts with no comment other than "120h GFS" aren't exactly the kind of posts we want to encourage. Please add some substance to your posts or we're going to have to start being more strict in cleaning up nothing posts.

Explanations are posted of upload failure...Nick

 

 FTP

Edited November 13, 2018 by BLAST FROM THE PAST

[bluearmy]

15 minutes ago, feb1991blizzard said:

Agree but its not impossible with a Greeny block

Still prefer the griceland option 

mind you, the hemispheric end to that run is incredible 

[bluearmy]

9 minutes ago, Daniel Smith said:

Well.. the vortex has gone to sleep for probably a good 2-3 weeks should the 12z come off as is

I think this run even beats "that ECM" from 2012. Very unlikely at this stage to actually come off, of course - But I certainly doubt it's without ensemble support.

It really doesn’t - we have very short memories - go and check the runs at the back end of Feb this year ..........

It is a beautiful sypnotic run re height rises and deep troughs and obliteration of the trop vortex but given the time of year, the uppers etc aren’t quite delivering away from the coasts and northern hills 

Where it takes us to is another matter ...

Edited November 13, 2018 by bluearmy

[ALL ABOARD]

2 minutes ago, Daniel Smith said:

Just to ground is back into reality for a moment, the ICON isn't amazing

Far too much energy around Southern Greenland/more of a Scandi/Euro high as opposed to a Scandi High as seen on the GFS.

Its all to do with the merging of the low around southern Greenland. The GFS doesn't merge it and therefore it allows the high to drift towards Greenland . BOTH UKMO and GEM merge the lows .

See below.

[feb1991blizzard]

3 minutes ago, bluearmy said:

Still prefer the griceland option 

mind you, the hemispheric end to that run is incredible 

Griceland gives less chance of the wishbone effect, but then again your best chance could be with a channel runner, which can happen with either.

[BLAST FROM THE PAST]

Displaced Vortex is a major player this winter....expect some extreme charts ‘throughout’ winter. 12z GFS is unbelievable.....which is why I sit and watch now.....

 

BFTP

[BleakMidwinter]

3 hours ago, terrier said:

Well this model output at the moment should come with a government health warning. As my parents used to say to me. If something is too true to be believed then it probably is. Think I will remain on the fence for a few more days yet. 

Just make sure you've got good warm mittens and hat on, while you sit on that fence - it could end up quite chilly, from all I can see!

[booferking]

4 minutes ago, ALL ABOARD said:

Its all to do with the merging of the low around southern Greenland. The GFS doesn't merge it and therefore it allows the high to drift towards Greenland . BOTH UKMO and GEM merge the lows .

See below.

Yes but I believe all models will get there a couple days after with the Azores high linking up control run shows my thoughts well.

[Derecho]

3 minutes ago, ALL ABOARD said:

Its all to do with the merging of the low around southern Greenland. The GFS doesn't merge it and therefore it allows the high to drift towards Greenland . BOTH UKMO and GEM merge the lows .

See below.

Yup this merging of the low is what we need to avoid. Send it south to the Azores and we are in for retrogression of the high to Greenland. It could still go wrong but the 12z GFS was spectacular. 

From the ens so far those that don't merge the low ~ T120 and those that do (what we want to avoid) are as follows.

No merging: 50%

Merging low: 50% (22 runs)

So its on a knifes edge. I'm keeping cautious because I remember last year in early December we were forecast to have a stonking Greenland high but it didn't materialise...

Lets keep our feet on the ground

[Decemberof2010]

Pretty impressive 192h GFS mean

[Methuselah]

End of the run not so spectacular as yesterday's pub run. That said the cold does come in much earlier, at Day 10! Still, with all that cold air around and a meridional-type flow (and the jet a long way south) the only way seems to be cold? Get the cold in first. Build it, they will come!

[Cheshire Freeze]

3 minutes ago, Quicksilver1989 said:

Yup this merging of the low is what we need to avoid. Send it south to the Azores and we are in for retrogression of the high to Greenland. It could still go wrong but the 12z GFS was spectacular. 

From the ens so far those that don't merge the low ~ T120 and those that do (what we want to avoid) are as follows.

No merging: 50%

Merging low: 50% (22 runs)

So its on a knifes edge. I'm keeping cautious because I remember last year in early December we were forecast to have a stonking Greenland high but it didn't materialise...

Lets keep our feet on the ground

Even if the lows don't split, the prognosis still looks highly amplified...which you can't always fall back on in these situations. 

It just feels like the destination is set, regardless of how many hurdles present themselves. Not often you get that impression.

[ITSY]

36 minutes ago, Day 10 said:

First post of the season, and what a time to join the party!

Day 10 is loving Day 10!

What a chart! Is 2010 about to be trumped!

Oh my goodness. That’s an astonishing chart should it come off. Incredible run 

[ALL ABOARD]

6 minutes ago, booferking said:

Yes but I believe all models will get there a couple days after with the Azores high linking up control run shows my thoughts well.

Im not disagreeing but the it tends to mean that to much energy is left for the high to retrogress easier, Id much rather a smooth sailing over the initial hurdle as we all know that one spoiler leads to another and another fingers crossed this time that all roads lead to rome.

As

[Mucka]

I know this is called "the hunt for cold" but has anybody actually seen any?

 

 

 

 

 

 

 

[Snowy L]

I dont think the UKMO would be that great beyond t144. As mentioned already GFS has those lows splitting in the Atlantic which allows another Atlantic high to build, and this acts as a guide for the Scandi High to migrate to Greenland. D6-8 is the one to watch, need to see those lows split.

[Cheshire Freeze]

2 minutes ago, ALL ABOARD said:

Im not disagreeing but the it tends to mean that to much energy is left for the high to retrogress easier, Id much rather a smooth sailing over the initial hurdle as we all know that one spoiler leads to another and another fingers crossed this time that all roads lead to rome.

As

Even if we miss the first bite, at the very least it looks like we'll get a vortex displacement which should aid us into December...best case scenario we have a December SSW to fall back on. The trop has done enough work by this point to almost guarantee us a December response of some kind. How often can we say that?

I think GP is on the same sort of lines.

Edited November 13, 2018 by CreweCold

[carinthian]

7 hours ago, carinthian said:

Morning all. Another mild day here , current temp at 2000m is 10c. However, forecast freezing level down to 1500m by Saturday morning. Just spoke to our experts and they are surprised at the speed of the Westward propagating trough caused  by cold advection as shown by the H Res ECM chart at early as 144t. Sort of also backed up by the UKMO model at the same time that indicates a localised area of low pressure to form near to SW  Britain. Their own model does not have a cluster of results to view but indicates a rather slower advection of the colder air towards the British Isles with continued development of a  strong cell of high pressure between Southern Scandinavia and Iceland. Longer term , ridging towards the Arctic indicate that Britain may have to wait for route to cold from the NE as they also think a more meridional flow to develop . Their model will get an update later today.

C

The route to cold is indeed from the NE ( see above post earlier ) looking at this latest chart from GFS. Rain turning to snow behind the Arctic Front across England and Wales and what looks like possible Polar Low  between Scotland and Norway. Certainly 500mb temps cold enough at -40c or more with plenty of convection over the sea. Will have access to outer perimeter snow forecasting model tomorrow ( 10 days ) so should be interesting to report back with thoughts from over here regarding the UK and the Alps.

C

Edited November 13, 2018 by carinthian

[Derecho]

6 minutes ago, CreweCold said:

Even if the lows don't split, the prognosis still looks highly amplified...which you can't always fall back on in these situations. 

It just feels like the destination is set, regardless of how many hurdles present themselves. Not often you get that impression.

We shall see, for what its worth I agree. If the low doesn't split things can still work out further down the line there would be more chance for things to go wrong

Anyways just pointing out the key player for newbies on here :). P16 is an example of where it all goes Pete Tong. Fingers crossed we succeed where early December last year didn't.

[Summer Sun]

UKMO and GFS getting closer at t144 just that low in the Atlantic they don't quite agree on

 

Edited November 13, 2018 by Summer Sun

[weatherguy]

1 hour ago, weatherguy said:

By 186 we see some lovely WAA heading up to greenland...hopefully this leads to some retrogression of the HP and that siberian PV lobe drops in behind.

Well well well...No hopefully needed there - the 12z GFS goes on to be a thing of immaculate beauty!  Brings back memories of "that ECM" a few years back with an incredible long-fetch north easterly! 

[ITSY]

Just now, Quicksilver1989 said:

We shall see, for what its worth I agree. If the low doesn't split things can still work out further down the line there would be more chance for things to go wrong

Anyways just pointing out the key player for newbies on here :). P16 is an example of where it all goes Pete Tong. Fingers crossed we succeed where early December last year didn't.

Equally th GEFS control is an example of what can happen where the lows don’t fully split but the second and third and fourth bites at the cherry do the job so we wind up in the same place, just a week later. I’d take that.