Model thread discussion - cold spell looming

[Man With Beard]

At the moment, snow won't be how this spell is remembered (except maybe Cornwall/Devon?!?) but it will be for cold. ECM looks like some spots in SE and central England may not see temperatures above 1C within the whole 10 days of its run.

It is a really close call between a UKMO and ECM ending. Not a lot in it at D5. I doubt the UKMO will be that mild except in the west, though. 

Also, bear in mind always the magic of blocking to the east. Not 72 hours ago the models unanimously pushed snow and rain right up into N Scotland. Now it doesn't get past Bristol, maybe not even that. That's a 500 mile turnaround. The point being, blocks to the east have a way of baffling the models even at short timescales. Is it even inconceivable the deep cold will come back?

[Cloud 10]

Good old day 10 from GEM and ECM.

[Jono E]

As we discussed earlier - Try not to get too disappointed with one model run folks ! - We have to get the attempted mild push out of the way on Friday and then see how the land lies - Twists and turns ahead folks and I would advise you keep the bigger picture in mind. Even ‘the professionals’ are uncertain regarding the weather at the end of the week ! 

[phil nw.]

A few off topic posts have been hidden.Please post any general chat or info regarding BBC/UK met forecasts in the relevant threads.

Ta very much.

[mulzy]

30 minutes ago, Man Without Beard said:

At the moment, snow won't be how this spell is remembered (except maybe Cornwall/Devon?!?) but it will be for cold. ECM looks like some spots in SE and central England may not see temperatures above 1C within the whole 10 days of its run.

It is a really close call between a UKMO and ECM ending. Not a lot in it at D5. I doubt the UKMO will be that mild except in the west, though. 

Also, bear in mind always the magic of blocking to the east. Not 72 hours ago the models unanimously pushed snow and rain right up into N Scotland. Now it doesn't get past Bristol, maybe not even that. That's a 500 mile turnaround. The point being, blocks to the east have a way of baffling the models even at short timescales. Is it even inconceivable the deep cold will come back?

Indeed, Heathrow raw maximums from the ECM run between -1.1C and 2.1C over the next ten days with a -10C minimum chucked in too.  That’s exceptionally cold for London.

Edited February 8, 2021 by mulzy

[bluearmy]

[Tim M]

25 minutes ago, phil nw. said:

A few off topic posts have been hidden.Please post any general chat or info regarding BBC/UK met forecasts in the relevant threads.

Ta very much.

Where is the bbc/Met forecasts thread please? Thanks

 

[TSNWK]

3 minutes ago, bluearmy said:

Interesting that Wednesday is the least cold day this week.   With the next 3 being a couple colder... Drawing in the cold surface air dispite a slight relaxing vin uppers

[Frigid]

9 minutes ago, bluearmy said:

Surely that’s not right. If it were then it well could be the Coldest February since 1991, for London anyways 

Edited February 8, 2021 by Frigid

[Drifter]

11 minutes ago, Tim M said:

Where is the bbc/Met forecasts thread please? Thanks

 

I’ve asked before and never been able to find them. No wonder people post them here instead. 
Mods - where *is* the correct thread?

[phil nw.]

8 minutes ago, Tim M said:

Where is the bbc/Met forecasts thread please? Thanks

 

Hi Tim,

Here is a list of all the sub forums on our Winter discussion page.There's plenty of options there.

https://www.netweather.tv/forum/forum/1-weather-discussion-winter/

More specifically the 2 below might suite.

Met outlook

We have a general winter chat thread where BBC forecasts can be discussed.

I hope that helps.

[Griff]

1 minute ago, Griff said:

A case of the proverbial... 

See you next Tuesday... To the return of the strong SPV... 

Latest ecm zonal winds... Obviously this is the strat and I have no idea where coupling with the trop or if any delay in interaction comes to pass... 

Edited February 8, 2021 by Griff

[phil nw.]

10 minutes ago, Drifter said:

I’ve asked before and never been able to find them. No wonder people post them here instead. 
Mods - where *is* the correct thread?

Hi Drifter,

I saw your post after my reply above to a similar enquiry.

Just to show again the link to the main Winter discussion page where all the sub forums/threads are listed.

https://www.netweather.tv/forum/forum/1-weather-discussion-winter/

[sheikhy]

Any news on the mean charts for ecm?!!

[stodge]

Evening all

Well, a real rarity - an ice day in lowland East London with maximum temperature of -1c. After the overnight snow, not much has been added but apart from some evaporation, very little has gone. A brief foray to sort out the bins confirmed a biting E'ly wind and a significant windchill.

Last evening the models seemed keen to prolong the cold spell past the weekend with GFS OP in particular offering a prolonged colder episode thanks to a retrogressing Scandinavian HP. I'm vaguely aware of some toys being thrown out the pram and some wailing and gnashing of teeth so we can assume that's now off the table (or can we, options get picked up, put down and retrieved all the time?).

T+120 is Saturday 13th, T+240 the 18th, T=312 the 21st and T+384 the 24th February.

Let's see how down the downgrades really are:

12Z GEM: - the least certain of all the models about prolonging the cold spell yesterday in all honesty, At T+120, pressure is high to the east and north east with twin HP cells of 1040 MB over southern Scandinavia and the North Sea. The Atlantic trough has two centres - the main centre sits well to the west having swung up from the south west and another LP has also swung north well to the west of Ireland. A SSE'ly covers the British Isles at this time - positive uppers have returned to Ireland and the far south west of England but remain below -4 over most northern and eastern areas. From there, the HP over Scandinavia quickly collapses south into Europe and by T+180 the Atlantic trough has elongated east to the north of Scotland a WSW'ly airflow covers the British Isles. The colder air has been pushed well to the north and east and 850s are generally either side of zero with the mildest air over the south by this time. From there, one secondary LP develops to the south of the main trough and runs north east close to the British Isles and by T=240 another secondary LP is crossing into the North Sea with a very windy spell over the Pennines. Heights persist to the south and far to the north with the trough elongating into Scandinavia by this time. 850s generally around zero by this time.

A disappointing start from GEM with the Scandinavian block offering very little resistance early next week to the Atlantic.

12Z GFS OP - the T+120 looks different to the GEM with a stronger HP over Scandinavia ridging to the east of Iceland and a SE'ly airflow over the British Isles. Milder air has reached Cornwall and the far south west of Ireland but elsewhere it remains cold with uppers below -8 over most of eastern and northern Britain.  From there, the Atlantic trough launches a sustained assault on the block which begins to weaken in situ or drift slightly north west. The trough aligns negatively and by T+180 one LP is pushing south east as it pushes against the block from the south west. After an initial pushback against the trough, milder air tries to come in again from the southwest but by T+180 has only reached south western areas but it has turned a little less cold elsewhere with the coldest air confined to northern and north eastern Scotland and the northern isles by this time. From there. another vigorous Atlantic LP forms to the south west and this finally breaks down the block with the residual HP declining east and a SSW'ly air flow setting up over the British Isles. Much milder air has now moved across all of western Europe with 850s of +4 over the British Isles.

What a difference a day makes!! A significant change from GFS OP with a powerful Atlantic trough breaking down the block - I'm struggling to see what signal has caused the change in the evolution and I suppose the obvious question is it's T+240, it's changed before and it can change again.

12Z Control: at T+120 it's very close to the OP but from there the Scandinavian HP puts up more of a fight than on the OP and while it starts to drift north west, the Atlantic LP is forced south east towards Iberia with a SE'ly air flow over the British Isles. Uppers remain negative everywhere with the coldest air (850s still below -8) over northern and eastern areas.  The attempt at retrogression, however, fails and the trough declines back east allowing the Atlantic trough to re-orient in mid ocean and send a new lobe of energy east by T+240 leaving the British Isles in a SSE'ly air flow.  Positive uppers by now over southern and western parts and it's less cold albeit with 850s still negative further north.

12Z ECM: I strongly suspect this model will follow the herd towards a milder evolution but let's see. The T+120 chart is more like GEM with a north-south wedge of heights over Germany, the North Sea and south west Scandinavia. The LP centre remains far to the west and a SE'ly air flow over eastern parts of Britain is a SSW'ly air flow further west. As you might expect, positive uppers have reached the west and south west but it remains cold with uppers below -8 over extreme eastern areas. From there and slightly surprisingly, ECM goes down a different route with the HP persisting to the north east and the Atlantic trough first elongating and then disrupting to the south west of the British Isles. This maintains a broad SE'ly air flow over all parts at T+192 with 850s still negative over almost all areas and below -4 generally over northern and eastern regions. From there, heights remain strong to the north through to T+240 with the next Atlantic trough held well back and a light E'ly over the British Isles. Uppers are either side of zero so nothing very exciting.

Oddly enough, it's not unlike last evening's evolution but it's very different to the other models.

Looking ahead, GFS OP and Control at T+312 and T+384 respectively:

Both end with Atlantic domination and with Control showing signs of the PV returning the OP - not so the OP.

Conclusion: there's no point denying the obvious - cold fans have taken several steps back this evening. Indeed. we're back to last Tuesday which had the cold spell ending by Thursday or Friday. We've gained a couple more days but by the end of next weekend it looks as though the Atlantic will break through in one form or another. I'm left then with the question - what has changed? The signal for a strong Scandinavian block grew during the week and on last night's output was formidable but tonight it's back to a quick collapse against a powerful Atlantic trough. 

I don't get it - seriously I don't. Let's see where we are tomorrow to see if this is a clear new trend or one of those instances of a signal picked up, discarded and then picked up again. We've seen it before - we'll see it again.

[Allseasons-Si]

The latest Fax chart is of interest,it has a more neg trough out to the SW and further SW compared to this mornings...

12z t72 v's 00z t84.

it also has a little feature in NE Scotland and a higher Scandi pressure at 1038mb,i do hope that these upgrades keep on popping up

hoping for a better run from the pub run as the 12z was dreadful but goes Pete tong in fl so plenty of interest/model output to come me thinks,the ECM was a good run and looks to retrogress the high to the NW into Greenland with a possible reload from the N/NE,it was showing this yesterday,...i think!

A look at the ECM ens trajectories,i have saved the 5th/6th and today's shows blocking to the north of the UK

 

and finally, a good covering of snow here(1cm),i know it's not much but hey! ho!,...better than nothing.

 

[Griff]

1 hour ago, Cloud 10 said:

Good old day 10 from GEM and ECM.

I'd be overjoyed to be incorrect, and even in the light of receiving so many "the ECM verifies better than [INSERT ANY MODEL NAME HERE]", if the GEM has lost the plot and the ECM comes out on top here. 

I've probably stated half a dozen times since December that the ECM was playing catch up with the GEM (and parallel... rip). 

If ever there was a time for the GEM to sit this one out then for me, this would be it. 

[Drifter]

18 minutes ago, phil nw. said:

Hi Drifter,

I saw your post after my reply above to a similar enquiry.

Just to show again the link to the main Winter discussion page where all the sub forums/threads are listed.

https://www.netweather.tv/forum/forum/1-weather-discussion-winter/

Edit: ignore, already answered !

Edited February 8, 2021 by Drifter

[Allseasons-Si]

17 minutes ago, sheikhy said:

Any news on the mean charts for ecm?!!

Here you go Shaky

12z v's 00z.

not as good as this mornings with the curvature backing SW in Scandi but lets see how tomorrow firms up. 

[Snowman.]

Just now, Allseasons-si said:

Here you go Shaky

12z v's 00z.

not as good as this mornings with the curvature backing SW in Scandi but lets see how tomorrow firms up. 

Moving away from big fat scandi high to that Icland high. Again similar to GFS.

This puts more pressure on the low and makes in more elongated. 

[Allseasons-Si]

1 minute ago, Snowman. said:

Moving away from big fat scandi high to that Icland high. Again similar to GFS.

This puts more pressure on the low and makes in more elongated. 

There is that,yes

i hadn't viewed all the models today but thanks for the heads up.

[Skullzrulerz]

8 minutes ago, Snowman. said:

Moving away from big fat scandi high to that Icland high. Again similar to GFS.

This puts more pressure on the low and makes in more elongated. 

Is this a better outcome for a cold outlook?

[Andypvfc]

4 hours ago, Frosty Winter said:

GFS 12z has a fantastic snow event next Monday. It shows what’s possible with this setup even if we don’t manage to develop another easterly.

Looks great providing it covers the whole Country mate, from North to South, West to East then it stays around and freezes for a week or so. What we don't want is a Storm Emma situation where it missed the North.

[TSNWK]

@Griff hello! Really on para? When you say RIP has it simply stopped coming out ? Or has there been a notification it is no more?

[chris55]

52 minutes ago, TSNWK said:

Interesting that Wednesday is the least cold day this week.   With the next 3 being a couple colder... Drawing in the cold surface air dispite a slight relaxing vin uppers

Im assuming the green bars are night time temps? If that's the case then Wednesday and Thursday are close to record breaking I would think.

The day time temps up to 0c vs -2C probably relates to the clear skys, a little solar input in the day and a very clear sky at night. Quite amazing night time temps!