Model output discussion - 7th January onwards

[stewfox]

2 hours ago, Catacol said:

In Dec 2010 we got a very swift transition to a deep scandy trough supported by a very sharp and strong greeny high - but it wasnt particularly long lived. It started to fade within a week because all the drivers were moving things back to a mobile pattern, and then the rest of the winter was unmemorable.

 

December 2010 was the second coldest in CET  350+ year history and ran past boxing day or are you just talking about the strong greeny high being short lived  ?

[swfc]

1 hour ago, Steve Murr said:

 

Icon looks great at 144 hrs!!! great push from pacific side and atlantic ridging.also I have no idea why sm is on my msg?

[NorthernRab]

12 minutes ago, stewfox said:

December 2010 was the second coldest in CET  350+ year history and ran past boxing day or are you just talking about the strong greeny high being short lived  ?

I think Catacol is referring to the initial (record breaking?) Greenland High in November 2010 which, if my memory serves me right, was actually forecast about 240 hours out or so before materialising. Again, if my memory serves me right, this was actually linked to warming in the Stratosphere at the time by one of the members on here when our understanding of Stratospheric led cold spells was still in its relative infancy. The high was relatively short lived in comparison to what is currently touted for the coming months and the second phase of cold weather came via a Scandinavian High (once again, if my memory serves me right) after a 5/7 day "mild" interlude. 

Anything near to that winter which produced 40cm of level snow here with 7ft icicles wouldn't go amiss! 

 

Back to the here and now, the ensembles continue to show great potential up here in Scotland 

Edited January 10, 2019 by NorthernRab

[karlos1983]

ICON decent at +144, cold air surging south!

Edited January 10, 2019 by karlos1983

[northwestsnow]

ICON quite noticeably colder than the 6z run at 144...

[Weathizard]

Icon has amplified the pattern more at 144, waiting to see how that low out west interacts with the attempted ridge 

[Catacol]

17 minutes ago, stewfox said:

December 2010 was the second coldest in CET  350+ year history and ran past boxing day or are you just talking about the strong greeny high being short lived  ?

Yes - cold month - but the real action kicked off here mid month

and by Xmas the writing was on the wall as the atlantic fired up and everything was pushed east

Very memorable December - but despite the great synoptics of early month it was too early then for heavy snow in many parts, and after a week or so of wintriness mid month it faded. This time around we have something of a similar starting point (scandy trough and "wedgie" heights out west) a month later in the season - and with the potential for the pattern to embed on the back of strat impacts that are still ongoing and a pacific pattern that has been in sympathy with a high lat blocking setup (though thus far it has been overriden)

I dont have time now for anything longer - but this is a very good 12 day GEFS anomaly chart with a bit of a mid Dec 2010 look about it, and with the arctic high set to strengthen further thanks to downwelling strat impacts it can probably only get more severe from here. Met text for extended suggests the same. More detail on that later.

 

Edited January 10, 2019 by Catacol

[Methuselah]

A wee while back, someone asked whether cool/cold zonality, sliders and such, often precede a change to very cold weather...We this one certainly did: it even gave one of the best White Christmases of the 20th Century! Though you'd hardly guess it from this chart?

Edited January 10, 2019 by Ed Stone

[karlos1983]

hmmmm, not sure I like the ICON ending, can see a route to South westerlies there.... 

Started with so much promise..

Edited January 10, 2019 by karlos1983

[winterof79]

11 minutes ago, karlos1983 said:

ICON decent at +144, cold air surging south!

Ahh how lovely those words echo....."cold air surging south"

Yes at 144z not 240 no.

[tight isobar]

6 hours ago, tight isobar said:

Any sustained block formats @/around greenland...will likely come as sudden pop up modeling...due to lobe responce1s...and indeed migration.

But-the amp-and phasing is certainly there..(for that scenario)..

Edit:

By this time nxt week my punt is thats where any split occurs...and could likely be modeled starkly by then...-via link with pac-punching= split -pv 

Re-edit:.

Still think canadian lobe being WELL OVERPLAYED ATM- and a major miss match on influencing factors!!!

ICON-further up'ing that pac/MLB(Atlantic) anti.

Reiteration-' likely split sector!!.

With again the mass canadian lobe being vastly overhyped via raws. .

See where all 12z drop and drive the scenario!!!

Edited January 10, 2019 by tight isobar

[Weathizard]

Interesting chart from the ICON, Cold air flooding in and attack coming in from the west, I highly doubt that low will be as strong as is on this chart, once again would have been nice to see past 180 on this one but it’s pretty much a guessing game. The 144 chart was pretty good.

 

[mountain shadow]

4 minutes ago, karlos1983 said:

hmmmm, not sure I like the ICON ending, can see a route to South westerlies there.... 

Started with so much promise..

It would a very difficult route to South Westerlies from there with pressure low over Spain. The lows South of Greenland would head South East I would think.

[weirpig]

1 minute ago, tight isobar said:

ICON-further up'ing that pac/MLB(Atlantic) anti.

Reiteration-' likely split sector!!.

With again the mass canadian lobe being vastly overhyped via raws. .

See where all 12z drop and drive the scenario!!!

You are right  the Vortex on the 12z icon is not as strong as the 0z run  quite a diffeence in regard to the greenland area.  Something to watch

[bluearmy]

There is a ridge ahead of the push from the Canadian vortex days 9/11

the bigger that ridge the more chance that this push can be disrupted a little west to bring some of the uk into slider territory 

[winterof79]

40 minutes ago, stewfox said:

December 2010 was the second coldest in CET  350+ year history and ran past boxing day or are you just talking about the strong greeny high being short lived  ?

I believe the cold spell was around 4 weeks to it's demise.I think Cactol was refering to that.

This on the horizon has the hall marks of eclipsing that longevity imho with all the background pieces falling into line .

Edit.

I think it will be the frequency of cold shots into N/W Europe during Feb and March that will test the metal and resources of our services as J Bastardi alluded to.

Sounds sensationalist but I'm here to be shot at 

Edited January 10, 2019 by winterof79

[Jonathan Rhodri Roberts]

3 hours ago, andymusic said:

cold and snow starting to show up circa 6 days and counting in Wales on the gfsp - coming ever closer

Looks decent for many but I'm in Porthcawl and it seems as though the Swansea Bay/ Vale of Glamorgan snow shield is still going strong mate, hope you're away from there if you like snow  

Edited January 10, 2019 by Jonathan Rhodri Roberts

[WhiteFox]

7 minutes ago, Catacol said:

Very memorable December - but despite the great synoptics of early month it was too early then for heavy snow in many parts, and after a week or so of wintriness mid month it faded.

I can't disagree with your analysis leading up to the mid-December 2010 outbreak and why it ended, but I don't agree that it was too early for heavy snow.

By December 21st cold enough airmasses are available to tap into and the lack of solar energy means that a lower temperature can be achieved at the surface under specific 850 values than could be achieved in early February when the solar energy input is greater.

The reason this does not generally happen is due to lag effects and is itself partly a result of atmospheric dynamics making it less likely that the cold air reaches us in mid-December than early February; in late November there is still residual heat being redistributed from earlier in autumn which has the effect of increasing low pressure activity. As the residual heat fades and the colder air from the northern hemisphere takes over the storm activity decreases and makes a leakage of cold more likely(expressed in terms I can understand!)

December 2010 was a rare occasion when we both tapped in to the perfect spot for a cold source and had very low solar energy due to the low sun. Mid December is perfectly capable of having temperatures every bit as low as late January.

 

Of course this is all very simplified and I could be talking utter tripe so I apologise in advance!

 

[Ali1977]

UKMO at 120 looks good to me, poss similar to icon at 144 with Northerly 

Mighty fine this from UKMO

Edited January 10, 2019 by Ali1977

[weirpig]

 UKMO 144  hello  cold northerly in a few days (if right )

 

 

 

Edited January 10, 2019 by weirpig

[swfc]

4 minutes ago, Ali1977 said:

UKMO at 120 looks good to me, poss similar to icon at 144 with Northerly 

Indeed great ukmo also!!!!

[warrenb]

I think we are seeing a shift in the short term here. ICON and Meto very similar at 144.

Edited January 10, 2019 by warrenb

[Weathizard]

UKMO and ICON look similar at 144, UKM is actually better and cleaner, someone tell them they need to let us see the charts after day 6!  

[warrenb]

Troughing in Europe ever so slightly further east allowing a gap between Euro and Canadian lobes.

[mountain shadow]

3 minutes ago, weirpig said:

 UKMO 144  hello  cold northerly in a few days (if right )

 

 

 

Finally!!