Model output discussion - deep cold inbound?

[Eskimo]

The ECM in a nutshell...

[KTtom]

6 minutes ago, Djdazzle said:

Pretty confident it will be. Just seems a bit keen with that low.

Certainly a world away from the Met who talk about the 'battle'going on for a further week than both ecm and gfs show!

[Purga]

Now there's a fascinating development!

goes to

This is becoming an intriguing situation and highlights how difficult it is to displace a cold block when in situ...

[sheikhy]

Anyone got the temps from ecm for next week!!pretty certain they will be cold!!!looks for those colder 850s to be further south on the 18z!!!im happy with the ukmo and ecm this evening!!very happy!

[Scott Ingham]

Remember the 13th spoken about to see full affects of +AAM behaviour?

Look at the 240 hour ecm chart on the 14th and the almost sudden rise in northern heights through Iceland.

First signs for me of this second bout of amp.

As it stands north of Birmingham might not warm at all with copious Battleground snow to be followed by renewed amplification and a repeat pattern 16th onwards as shown by the CFSV2 (with the extremity of that certainly in question )

Theres still enough time and enough in the envelope to also keep the south on the right side of the warmth as well so if i was in the North i wouldnt be celebrating being buried after the easterly winds and if in the South too despondent as it was only this morning the 0z ecm showed how we can only stay on the right side of the cold if the pattern trends further south (which it does historically) deep cold isnt easy to push away

[Chesil View]

2 minutes ago, Purga said:

Now there's a fascinating development!

goes to

This is becoming an intriguing situation and highlights how difficult it is to displace a cold block when in situ...

Thats what I thought to Purga, just imagine if this weekend and next week are not really the main course and that was yet to come.

[Drifter]

JMA ends the whole thing by 144hrs!

[Griff]

1 hour ago, Snowman. said:

Quick! someone post the CFS before everyone loses there mind!

 

6 minutes ago, Purga said:

Now there's a fascinating development!

goes to

This is becoming an intriguing situation and highlights how difficult it is to displace a cold block when in situ...

 

3 minutes ago, Scott Ingham said:

Remember the 13th spoken about to see full affects of +AAM behaviour?

Look at the 240 hour ecm chart on the 14th and the almost sudden rise in northern heights through Iceland.

First signs for me of this second bout of amp.

As it stands north of Birmingham might not warm at all with copious Battleground snow to be followed by renewed amplification and a repeat pattern 16th onwards as shown by the CFSV2 (with the extremity of that certainly in question )

Theres still enough time and enough in the envelope to also keep the south on the right side of the warmth as well so if i was in the North i wouldnt be celebrating being buried after the easterly winds and if in the South too despondent as it was only this morning the 0z ecm showed how we can only stay on the right side of the cold if the pattern trends further south (which it does historically) deep cold isnt easy to push away

 

2 minutes ago, Broadmayne blizzard said:

Thats what I thought to Purga, just imagine if this weekend and next week are not really the main course and that was yet to come.

Perhaps I shouldn't have laughed so loudly at the CFS earlier,

[Scott Ingham]

1 minute ago, Griff said:

 

 

 

Perhaps I shouldn't have laughed so loudly at the CFS earlier,

Maybe not for a very crude representation of pattern potentially by then but them 850s

[Mike Poole]

Well, I am taking some time to work out what I think from the 12z suite, having looked at all of them. Maybe the following take aways:

• The start of the cold spell is nailed-on - well we knew that from yesterday.
• NH profile looks great early on in the runs, and crucially there is a wedge extending from the Greenland height rise towards Scandi that allow the earlier low to go under.  T144.  Cold air in place to this point.
• Then, the bigger atlantic low approaches, same time the NH picture starts to get a bit messy.  
• I think this is now well into FI and what should happen is the NH profile doesn’t get messy and the bigger low disrupts and goes under.  I’d be astonished if it didn’t, but we can only wait and see...but if that low does go under, the next one will too.
• This is so tight that I can’t see -8C uppers over the whole country all the time, these lows even if they undercut will pull in warmer air to the SW and maybe further...but this is the high risk high reward spot for snowfall.

Interesting times...

[tight isobar]

6 minutes ago, Scott Ingham said:

Remember the 13th spoken about to see full affects of +AAM behaviour?

Look at the 240 hour ecm chart on the 14th and the almost sudden rise in northern heights through Iceland.

First signs for me of this second bout of amp.

As it stands north of Birmingham might not warm at all with copious Battleground snow to be followed by renewed amplification and a repeat pattern 16th onwards as shown by the CFSV2 (with the extremity of that certainly in question )

Theres still enough time and enough in the envelope to also keep the south on the right side of the warmth as well so if i was in the North i wouldnt be celebrating being buried after the easterly winds and if in the South too despondent as it was only this morning the 0z ecm showed how we can only stay on the right side of the cold if the pattern trends further south (which it does historically) deep cold isnt easy to push away

Good to see ya bk.. and as per good analysis

[Scott Ingham]

Just now, tight isobar said:

Good to see ya bk.. and as per good analysis

Thank you my mate! Good to be back!

[Cold Winter Night]

If you take a step back and you compare yesterday's 12z with today's you will notice exactly what many have already said:

That cold air mass will not move that easily, and heights to the North and East are underestimated.

At 168h yesterday, 144h today, you see better surface heights over Scandinavia, and the Atlantic low, although deeper, is more to the South. The reason it's stalling: cold air mass ahead.

Moving on to 216h yesterday, 192h today, the difference has become very clear. Yesterday a slider was out of the question, today: that's exactly what happens afterwards, building new heights ahead.

Now think about this:
What if EC still underestimates that block?
What could happen?

Then add what @Scott Ingham just mentioned: increased AAM.
What are the possibilities?

I am very positive about the rest of this month. I could be proven wrong, certainly. But what I see happening in the output is very encouraging in my opinion.

Edited February 4, 2021 by Cold Winter Night
Typos corrected

[Scandinavian High.]

All models are wrong  past 144 models can’t even get t96 right..

[Frosty.]

For those of us hoping the very cold air is still in situ at T+240 hours..me..me..me..me...here’s a few GEFS 12z members which oblige!  

[mulzy]

Could be a temporary swing with this eps suite but days 7-9 mean is quite a bit milder than this mornings suite.  Iberian heights the issue.  The op is probably middle of the pack with regards temps.

Edited February 4, 2021 by mulzy

[Anthony Burden]

ECM as per GEM  ICON UKMO keeping at bay Atlantic,also although 240 hrs showing

Scandinavian 1030mb high,GFS seems very isolated we of course will see.

My take as stated in other blogs,A cold / very cold lengthy period coming up 

severe frosts,snow in many places can not ask for anything more.

[sunnijim]

9 minutes ago, Griff said:

 

 

 

Perhaps I shouldn't have laughed so loudly at the CFS earlier,

CFS signposted the upcoming freeze,so not to be sniffed at in any way.

Edited February 4, 2021 by sunnijim

[chris55]

With such a "lump" of cold air entrenched over NW Europe we need to take the raw operational (and ensemble) data with a degree of scepticism, more than we would in a normal Zonal flow.

We are all aware of model bias reverting to type, and how the models also struggle with a cold block vs and Atlantic incursion.

Thats not to discount any outcome be it mild or colder but it is sensible to read the charts rather than take them at first view.

We can see how EC stops the Atlantic making any full incursion between 168 and 240.

168

216

240

 

 

 

[tight isobar]

6 minutes ago, mulzy said:

Could be a temporary swing with this eps suite but days 7-9 mean is quite a bit milder than this mornings suite.  Iberian heights the issue.  The op is probably middle of the pack with regards temps.

The Iberian fed pump was always  the kick in the teeth.. however they are miss-modelled atm by was of sequence.. as we have seen  via various suites... one to watch...

Edited February 4, 2021 by tight isobar

[BLAST FROM THE PAST]

Beeb London has 1c for London on Sunday with the snow moving in....that’s cold!

re ECM, and GEM I concur...the blocking imo isn’t going to get just shunted away.  I’m expecting more tweaks and a more visual cross board shift towards that after Sunday.   

1c for Central London...sub zero Home Counties.  Up north will already be sub zero 
 

BFTP

[Mr_Pessimistic]

Hi, does anyone have a link to ecm ppn charts?, can't get them on metecioel, if they exist?    Thanks.

[stodge]

Evening all

A mixed day here in lowland East London with a spell of rain around lunchtime either side of which dry and indeed quite mild. Last evening's models suggested a rapid transition to much colder conditions but those conditions only lasting 3-5 days in the south and a shade longer further north though the "breakdown" was perhaps less convincing then the night before. Some of the models were showing a return of the PV to Greenland/NE Canada but the problem perhaps was the Atlantic energy, if unable to break through initially, finally broke through because rising heights to the south over Iberia prevented the negative alignment option.

Let's see if our upcoming cold spell is perhaps improving in terms of longevity irrespective of that severity may come in the more immediate period.

T+120 tonight is Tuesday Feb 9th, T+240 is Sunday Feb 14th and T+384 is Saturday Feb 20th

12Z GEM: at T+120 an E'ly covers all parts of the British Isles with LP over Biscay and heights to the north west and north east and a deeper LP approaching upstream from the west. Uppers generally below -8 and pockets of -12 uppers in southern and central England. From there, the next Atlantic LP also heads south east towards Biscay and by T+180 is approaching France with an ESE'ly air flow over the British Isles. Heights are now over Scandinavia as the trough has extended north west to a weak secondary LP over Iceland. Upstream, there are hints of further amplification. Milder air has reached the far south west with positive uppers over Cornwall and it's less cold over southern England but uppers remain below -8 over Scotland, Northern Ireland and most of Northern England. Moving on, the LP stays to the south and ends as a weak future over Holland by T+240. Heights ridging into Scandinavia persist ad there's an E'ly air flow over eastern areas. Further west, the Atlantic trough is moving towards the British Isles and a weak S'ly has set up over Ireland - all the signs of a possible battleground. Cold air with uppers below -8 remains over northern parts while uppers are below zero negative with the least cold air in the south east.

1-0 to cold spell longevity tonight - the north has a clear week of cold or very cold conditions while the south sees less cold air but the evolution has moved back to cold tonight with no clear breakdown by T+240.

12Z GFS OP - if you want a definition of a textbook E'ly OP at T+120 has it. LP close to south west England and heights to the north and north west. 850s below -8 from the Midlands north but -4 to -8 in the south so slightly less cold than the GEM down to the trough being closer to southern areas. From there, heights to the north and east persist but the Atlantic trough doesn't slide south east as heights rise into Iberia turning the alignment of the trough positive as a small lobe of energy crosses southern Britain at T+180. Less cold air has already returned to most parts of the British Isles with uppers just negative leaving the coldest air to the far north east of Scotland and the Northern Isles.  From there, the trough remains to the west of the British isles as heights build in from the south west and a mild or very mild SW'ly is in place by T+240. Uppers of +4 cover the whole of the British Isles by this time.

1-1 - OP cuts the cold spell short so it's just 3-4 days in the south and not much more in the north and by Valentine's Day it's almost spring like even though there's no sign of a PV  so could we see heights build to the east in further FI?

12Z Parallel - The T+120 chart looks better than the OP with a truer E@'ly and the LP further south over Biscay so much more like GEM. However, the next Atlantic feature is already deepening to the west. 850s below -8 over most of the British Isles at T+120 with pockets of -12 air to the south and east. From there, the Atlantic LP doesn't go anywhere quickly but spawns a new vigorous LP which threatens to move towards Ireland and in so doing raises heights to the south and introduces a SSE'ly air flow to most parts. Heights persist over Scandinavia. Milder air is close to the south west by T+180 but uppers below -8 persist over northern and eastern regions. From T+180, the "battle" between the air masses is quickly resolved as the Scandinavian HP declines south and a very mild SSW'ly crosses the British Isles  albeit with the trough much weaker to the west and a hint of renewed amplification upstream as heights cover most of eastern and central Europe. 850s of +8 approaching the south and south west so again a very mild mid month.

2-1 to mild with the Scandinavian heights quickly collapsing south but a better overall evolution than GFS OP in that the cold hangs on for a couple of days longer.

12Z ECM: at T+120, it looks a bit like the GFS OP (which doesn't bode well) with the LP close to Cornwall but a noticeable ESE'ly flow especially over northern areas. Uppers below -8 over most of the British Isles, perhaps a little less cold to the far south west. From there, the E'ly fades as the next LP takes a more northerly track. By T+192, a SE'ly air flow covers the British Isles as a shallow LP approaches Ireland but weak heights persist over Scandinavia. Milder air with positive uppers has moved back over southern and western regions but it remains cold with uppers below -8 over the far north and north east of Scotland. From there, ECM goes its own way with heights persisting over south west Scandinavia and extending back north west and as a result the Atlantic trough elongates and fills in situ not reaching the British Isles by T+240. It's a stand off between milder air to the south and west and colder air to the north and east.

 

For the south and west it ends 3-1 to mild but for the north and especially the north east it's 2-2 with the cold persisting throughout to T+240.

 Looking further ahead, the T+312 and T+384 charts from OP and Control respectively:

Plenty of interest in far FI and more than a hint of an anticyclonic pattern developing which will please those fed up with rain and flooding. Control also ends anticyclonic - whether we can get the HP in a favourable position to advect any colder air remains to be seen.

Conclusion: - there's a real split tonight. GEM and ECM are definitely toying with the idea of extending the colder spell into mid month but GFS isn't interested at all doing its usual thing of blowing up huge Atlantic depressions which crash through blocks with ease. That might happen but it's interesting the European and Canadian models are looking at other options. ECM would certainly be the most interesting longer-term evolution for cold fans but of course we have the early part of next week to enjoy or endure (delete as appropriate). I do think we need to get the LP as far south as possible as T+120 and hope we see stronger heights to the north east.

[Geordiesnow]

6 minutes ago, Scandinavian High. said:

All models are wrong  past 144 models can’t even get t96 right..

It's a bit of a bug bear or mine when people are saying the models can't get it right at 96 hours because it's just not true. DETAILS will change, slight changes could mean a bit of a difference in terms of temperature as we seen in the SE at times in the past few days but All models have been going for this easterly for days now, there is of course variation but the trend has been strong. 

Now the easterly is nailed on, then the medium term is definately all eyes out into the Atlantic, the potential for a battleground set up is definately there but as I say, details will vary from run to run. What seems more certain, there will be a large low out in the Atlantic but what affects it has on our weather remains to be seen. Traditionally the cold air does hang on for a bit longer and because we are looking at upper air temps perhaps as low as - 12 then there's a good chance the cold air will hang on but even if the low is much closer then its going to take quite a bit to wipe out the cold air. Interesting times. 

[Cold Winter Night]

5 minutes ago, mulzy said:

Could be a temporary swing with this eps suite but days 7-9 mean is quite a bit milder than this mornings suite.  Iberian heights the issue.  The op is probably middle of the pack with regards temps.

In line with the Operational run perhaps?

That can be a good thing, Iberian heights dragged up mild Southerlies  January 18-20 1947.

What did EC 240h remind me of? (a little bit) January 19 1947...