Model output discussion - 7th January onwards

[captaincroc]

6 minutes ago, Tim Bland said:

GFS Para  

I'm guessing this is when the vortex splits and one of the coldest lobes has drifted over Scandinavia and then picked up strength over the North Sea?  I've always wondered if that could happen and what fun it could bring? As the coldest lobes normally drift over to Canada, would be pretty interesting if the coldest lobe came our way instead.

[Matty88]

23 minutes ago, Tim Bland said:

GFS Para  

Very nice but a fantasy chart I'd say! Nice to see it though 

[Tom Quintavalle]

13 minutes ago, abbie123 said:

Hi all if that chart verified what would be the outcome thanks..

Here's the 850 chart, to accompany abbie123's (my fellow Bromleyite) chart. As Ali1977 suggests above, utter carnage is an apt description, I would've thought. Have seen Forecast charts similar to the above but don't think I've seen one come to fruition quite like this one, if it happened. Would be nice to experience a visit from a chunk of the PV, for once.

Regards,

Tom. 

[Man With Beard]

I hadn't seen the ECM ensembles from last night until now, but from a quick glance, I'm thinking it's becoming more and more likely that an onset of something cold will be happen between 21st and 24th January. By 24th, there's less than 10% of members exceeding 6C in London during the daytime (very low), and most clustered between 1C and 4C.

This morning's ensemble details to come later.

Edited January 10, 2019 by Man With Beard

[SMU]

Debilt T2Ms looking colder & colder now

control run must be Easterly-

@bluearmy

[SLEETY]

LOL the chance of gfs parallel nailing the track of the derpression this far out,if it even forms in the first place ,is about the same as Burton getting to the league cup final.Just ignore that run.

Edited January 10, 2019 by SLEETY

[bluearmy]

3 minutes ago, Steve Murr said:

Debilt T2Ms looking colder & colder now

control run must be Easterly-

@bluearmy

Diving lows (well placed for the uk to stay on the cold side ) and a developing scandi high ... quite plausible 

Edited January 10, 2019 by bluearmy

[johnholmes]

37 minutes ago, knocker said:

The ext GEFS and EPS mean anomalies this morning are fundamentally in the same ball park,particularly with the upstream pattern.There we have the Aleutian low/Alaskan ridge into the Arctic complex and the main vortex lobe northern Canada with associate trough down eastern North America, Thus a strong westerly upper flow exiting the eastern seaboard across the Atlantic which is where we hit the discrepancy with the EPS having a much more amplified ridge mid Atlantic against the gfs flatter flow. Although both scenarios would portend unsettled weather with temps below average the detail will very much depend on getting this sorted via the det runs.

Last night's NOAA was between the two but tending towards the EPS

 

Yes the anomaly charts ( I use) are still not totally of the same 'mind' so to speak, two with mid Atlantic ridging into a trough over Europe the third still with a flatter Atlantic flow. So still not able, out to 10 days, to show a definite change of pattern. The chart 8-14 NOAA, shown by k, does suggest this is more likely beyond day 10, the second day/evening it has shown this. So some increasing confidence that a more meridional pattern is going to be getting established by 2 weeks from now.

Edited January 10, 2019 by Blessed Weather
Moved text outside quote box.

[BLAST FROM THE PAST]

27 minutes ago, captaincroc said:

I'm guessing this is when the vortex splits and one of the coldest lobes has drifted over Scandinavia and then picked up strength over the North Sea?  I've always wondered if that could happen and what fun it could bring? As the coldest lobes normally drift over to Canada, would be pretty interesting if the coldest lobe came our way instead.

The coldest lobe stays over Canada (-40c uppers!!!)  but it is further W/NW away from Greenland (what we want) and we get a displaced chunk that heads our way.  Importantly though we see -20c deep cold build over Scandinavia and a HP wedge build over there.  -20c wedge heads into Iceland from the Pole and astonishing cold wedge coming off Maritime Canada in a pincer movement.......heading towards us, with deep cold wedge over Scandi.  Only one route from there.......I think it shows the potential cross polar movement of cold RJS was explaining.

 

BFTP

Edited January 10, 2019 by BLAST FROM THE PAST

[Banbury]

29 minutes ago, Ali1977 said:

Country wide snow (feet in places), blizzards, severe drifting , ice days, and 100% carnage on the roads and rail system. Especially hard hit in the East and South. 

It wouldn’t be melting the day after neither, severe frost (-15c in place ) once it all settled down and the LP moves off 

And Id be perfectly happy with that - I guess that is due to a 'steering' high????

I have to say I'm still a tad concerned I don't see sustained blocking at Greenland 

[tight isobar]

38 minutes ago, Banbury said:

And Id be perfectly happy with that - I guess that is due to a 'steering' high????

I have to say I'm still a tad concerned I don't see sustained blocking at Greenland 

Any sustained block formats @/around greenland...will likely come as sudden pop up modeling...due to lobe responces...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!!!

Edited January 10, 2019 by tight isobar

[Ali1977]

5 minutes ago, Banbury said:

And Id be perfectly happy with that - I guess that is due to a 'steering' high????

I have to say I'm still a tad concerned I don't see sustained blocking at Greenland 

Obviously it’s way in FI but if that Para came off I think it would be a pretty historic event , definitely memorable that’s for sure. Many snow lovers would sacrifice a prolonged cold spell to experience several days of that run I’m sure

[Selliso]

24 minutes ago, BLAST FROM THE PAST said:

The coldest lobe stays over Canada (-40c uppers!!!)  but it is further W/NW away from Greenland (what we want) and we get a displaced chunk that heads our way.  Importantly though we see -20c deep cold build over Scandinavia and a HP wedge build over there.  -20c wedge heads into Iceland from the Pole and astonishing cold wedge coming off Maritime Canada in a pincer movement.......heading towards us, with deep cold wedge over Scandi.  Only one route from there.......I think it shows the potential cross polar movement of cold RJS was explaining.

 

BFTP

Omega?

[Weathizard]

What happened to our arctic high? Weak effort! The ridge over the Pacific side is on becoming prominent though

u

[summer blizzard]

It looks like the 18z last night was indeed an outlier in amplifying straight away. The Euro and both GFS models have returned to yesterday’s pattern of events which is essentially that winter arrives for Scotland on the 17th via a nnw, winter arrives for the bulk of England on the 20th/21st via Wnw which all been well should push showers well inland. Afterwards there are some runs and ensembles trying to bring easterlies albeit at that range the signal is still incoherent.

[Penicuikblizzard]

59 minutes ago, Ali1977 said:

Country wide snow (feet in places), blizzards, severe drifting , ice days, and 100% carnage on the roads and rail system. Especially hard hit in the East and South. 

It wouldn’t be melting the day after neither, severe frost (-15c in place ) once it all settled down and the LP moves off 

You can dream

[Methuselah]

My my, what an optimistic start to the day, for a change! Hopefully, within the next couple of days or so, wintry charts will start to appear more generally before Day 10?

I can't wait!

PS: Being both autistic and a SAD-sufferer, early optimism kinda makes my day!

[Glacier Point]

Extended EPS T2s and T850s dipping at the very end of the run, which would be against model bias to drift back to climatology.

I'm struck at the moment by the Scandinavian trough and daughter vortex over Canada. Perfect mirroring of the stratospheric pattern. This is a clear influence which does not fit troposheric drivers. Between the two features, uncertainty abounds, but you can't escape the model trend for deep cold uppers forecast within the Canadian vortex. That should, against other signals, continue to remove the Greenland High option. I think more +ve height anomalies and a more likely mid Atlantic ridge rebuilding but not necessarily Greenland Highs are of the order, and tonight's EC run will be viewed with interest - there could well be a very slow downwell of the stronger -U wind anomalies from the warming to come which might be the trigger, although I'd like to see some more NAM plots to get a proper handle on this.

The tropical wave signal is moving extremely fast. By week 3, we could well be back to Dateline convection and Eastern Pacific. Again, good signal for sustained cold.

Other features catching my eye: the deeply negative state of the Arctic Oscillation (not unexpected for the second half of the winter); and, related to this, the ridge extending into the Arctic from Alaska modelled to break off and move towards Siberian sector. With the clockwise rotation developing in the Arctic lower tropospheric flow, this shows signs of moving towards Svalbard by month's end. With the European trough embedded, that makes for some interesting permutations for February.

Edited January 10, 2019 by Glacier Point

[Paul_1978]

1 hour ago, nick sussex said:

A very underwhelming GFS  00 hrs run which never delivers much in the day ten period . 

 

 

That's OK, because cold and snow hunters are not anticipating anything within 10 days anyway?

[summer blizzard]

3 minutes ago, Paul_1978 said:

That's OK, because cold and snow hunters are not anticipating anything within 10 days anyway?

The change comes around day 10/11 which is also what the 0z shows on gfs, gfsp and euro who all back a cold cyclonic wnw. From there we should look to the cold embedding as lows sink.

[Lloyds32]

So the more experienced members seem to think that Greenland High blocking features can be forgotten, and just the odd Atlantic ridging may bring NW blasts of cold air. This has been seen quite clearly in GFS FI. February now we should be looking too for a different pattern? The hunt certainly goes on...

[Selliso]

Well, the Para has me under -10-ish uppers from about 23rd Jan!

We'll ignore pet 13, which is clearly wrong....

Starting to allow myself to feel more positive now about a colder phase of the winter...

Don't need Roy Castle or Cheryl Baker on hand just in case it's a record breaker - some decent cold and snowy shots will do for me!

 

Edited January 10, 2019 by Selliso

[Glacier Point]

Blocking features are not necessarily Greenland Highs. Within the context of a deep cold trough across NW Eurpe, you don't need strong blocking features. These are however still potentially on the table for the week 3 period, and would represent the icing on the cake.

We go below average on the 16th, and remain there after.

Edited January 10, 2019 by Glacier Point

[SMU]

4 minutes ago, Lloyds32 said:

So the more experienced members seem to think that Greenland High blocking features can be forgotten, and just the odd Atlantic ridging may bring NW blasts of cold air. This has been seen quite clearly in GFS FI. February now we should be looking too for a different pattern? The hunt certainly goes on...

I think you need to go & reread what these posters are writing...

The protracted next cold spell starts end of days 6 for Scotland.. (16th) Into Day 7 for England.

Then as the cold becomes entrenched we are looking at the jet axis to see where the atlantic will slide across the UK

That may mean a temporary warm up ( for the SW & Ireland ( Maybe even the south ) however essentially day 6 is the start point with more emphasis on deep cold from day 9- That interim period 7-9 could be quite Snowy for some...

Edited January 10, 2019 by Steve Murr

[Nick F]

20 minutes ago, Glacier Point said:

Between the two features, uncertainty abounds, but you can't escape the model trend for deep cold uppers forecast within the Canadian vortex. That should, against other signals, continue to remove the Greenland High option. I think more +ve height anomalies and a more likely mid Atlantic ridge rebuilding but not necessarily Greenland Highs are of the order, and tonight's EC run will be viewed with interest - there could well be a very slow downwell of the stronger -U wind anomalies from the warming to come which might be the trigger, although I'd like to see some more NAM plots to get a proper handle on this.

Yes, have been a little concerned by the gaining strength and depth of the Canadian tropospheric vortex, some pretty deep cold/low thicknesses developing there in the models, and could be a spanner in the works in further delaying high latitude blocking forming to our north because of the predisposition of low heights to our NW.

Mirrored by the stronger daughter stratospheric vortex 9 days away

So I agree, could be more difficult to get the Greenland height rises, so perhaps we may need to look at getting some form of height rises/pressure build to the NE if likely amplification induced by MJO wave working through later in the month allows. 

So, although there is potential still for mid-Atlantic / Greenland height rises, this potential looks less likely or delayed unless the models are over doing the Canadian Vortex. But could still see sufficient temporary high pressure 'wedges' through late January to allow some cold and snowy snaps and I still think that blocking will become more prominent as we start February, given the eventual weakening of the tropospheric vortices and tendency for easterly winds in the lower stratosphere to start to impact the troposphere at high latitudes.

 

Edited January 10, 2019 by Nick F