Model output discussion 24/01/21

[Battleground Snow]

ECM extended looks good on these charts but the corresponding 2m temps are only a little below average for Western Europe

 

Edited January 25, 2021 by Battleground Snow

[AFCBSNOW]

17 minutes ago, Tim Bland said:

So you think all of the Uk is in with a shout of snow at the end of this week ? By ‘good’ I assume you mean cold and snow?  And you describe the fax as ‘good for all the Uk’ You don’t have to go into the regionals to refer to areas of the UK when describing what a chart shows, and no chart I have seen today shows snow (other than an hour of sleet) for over half the UK?

In fairness Tim, I don't think that is what he is suggesting.  I think he is stating that the continued pushback of the Atlantic in this scenario is good overall in the long term for the UK.  I haven't seen a single flake yet, but there is always hope until there is none.  

[SilverWolf]

49 minutes ago, Tim Bland said:

I think everyone needs to accept there is an element of IMBYism happening with posts, which is entirely natural. 

Yeah totally agree, everyone is doing it...... 

[icykev]

10 minutes ago, tight isobar said:

And so it shouldn't \wouldn't..especially with the vast impactual

human input ;faxes:....on we watch !✌

✌ Welcome back, hope your cool.

Lets reel this deep cold in . . .

You bring great posts to the table.

Looking good @Mike Poole 

 

[Man With Beard]

*Cherry picking alert!* What's really drawn my eyes on the ECM ensembles are the members that send Sunday's low (not Saturday's) on a slight negative tilt, bringing continental air into the first front. Needs watching. Here's an example:

[sebastiaan1973]

1 hour ago, winterof79 said:

Have a look on the up side for once its great. Stalling front this week ....yes this week

i try to be realistic. That's all. I can deal whatever the weather brings. Emotions are part of a passionate experience of the weather

[stodge]

Evening all

After yesterday's excitement, a much quieter day in lowland East London and pleasant in the winter sunshine after a very cold start. Milder weather is at hand however and the start of a 7-10 day milder interlude in the south but further north the extent and longevity of any milder spell very much up in the air (no pun intended). Moving further into February and hints continue of a new pattern change to something colder and perhaps more settled but we'll see.

12Z GEM: T+120 takes us to Saturday January 30th and with a shallow LP along the Channel and heights extending south east from Iceland, a NE'ly air flow covers the British Isles.  A trough extends from the Channel across northern Europe while a vigorous Atlantic LP churns NE across the ocean far to the west.  Uppers below -4 cover most of the British Isles but with milder air hanging on in the far south west and colder air moving into Scotland. The block to the NE, albeit weak, is enough to cause the Atlantic LP to disrupt with one portion singing NW toward southern Greenland and the other moving east towards the British Isles by T+180. SW'ly winds have moved back into southern and western areas with a SE'ly across northern and eastern parts. Milder air with positive uppers is confined to the far south by T+180 with colder air elsewhere and -8 uppers persisting over Scotland. From there, heights continue to develop to the south of Iceland and ease SE to southern Norway with an E'ly across southern and eastern Britain as LP moves south into Europe by T+240. Cold air with uppers below -8 covers most of the British Isles.

GEM is about as good an evolution as any cold fan would want ending with a frigid E'ly and, you'd imagine, plenty of snow for southern and eastern parts.

The GEM snow chart tells its own story.

12Z GFS OP - GEM is a near impossible act to follow. At T+120, quite different close to the British Isles from GFS OP with a weak HP over eastern parts and the Atlantic LP churning NE to the far west with little signs of further heights from Iceland and a residual LP over the Baltic. 850s just negative over most of the British Isles by T+120 - mildest air to the south west and coldest along the east coast. From there, the heights close to the British Isles soon fade as the Atlantic trough comes in and takes over just to the west of Ireland and by T+180 is pretty much still there with a complex trough in charge - the main centre is to the south west of Ireland and there is a ridge of HP over Scandinavia. Mild SW'ly winds over most southern and south-western parts of the British Isles by this time - positive uppers there and only slightly negative elsewhere. From there, the trough crosses over the British Isles but the LP is held to the east by the block over Scandinavia and by T+240 the trough is filling in situ with heights building upstream in mid-Atlantic. There's a slack cyclonic flow over the British Isles with slightly negative uppers in all areas except the far north where the air mass is colder.

Not surprisingly, GFS OP is not as good for cold fans as GEM but some helpful signs at T+240.

12Z Parallel: at T+120 Parallel is closer to GEM with heights to the north west extending from Iceland and LP to the south over the Channel leaving a NE'ly flow across the British Isles. Upstream, a brief ridge is followed by a vigorous LP moving NE in mid-ocean.  Uppers are below -4 in almost all parts of the British Isles with only the far south west keeping a little milder. From there, the Atlantic trough gradually moves in and disrupts north-west and east forming an elongated and complex trough with one centre to the south west of Iceland and the trough flow extending east across the north of Britain. Further south, a strong W'ly airflow is in place with a secondary LP deepening and moving toward the British Isles from the south-west. Milder air has extended across all parts with uppers either side of zero at T+180. The secondary LP duly moves across the British Isles and heights rising in mid Atlantic start to drag the whole trough east towards and across the British Isles by T+240.  Two shallow LP, one over southern Britain and another to the north west are moving east with heights now rising again to the east of Iceland. The air mass over the British Isles remains average - mildest in the south, coldest in the north but nothing too dramatic.

Once again, you'd think the evolution from T+240 would be towards something colder but we'll see in a moment.

But first, 12Z ECM - by T+120 there's a weak HP to the north west of Scotland with an LP over northern France and that pulls a NE'ly air flow across the British Isles. Uppers of -4 to -8 over all parts of the British Isles by this time. From there, the Atlantic trough takes over and by T+192 there's a SW'ly air flow over all parts with one LP to the north of Scotland and the controlling LP to the south west of Iceland. By that time, milder air is into south-western parts but 850s are still slightly negative elsewhere. By T+240 ECM isn't very far from Parallel with the trough filling as it moves east over the British Isles and upstream amplification. Negative 850s over all parts by T+240 with colder air moving into the far north west.

ECM ends similar to Parallel this evening with upstream amplification and the trough filling as it moves east across Britain.

Time to look further ahead with the T+312 (Feb 7th) and T+384 (Feb 10th) charts from both OP and Parallel.

You pays your money, you takes your choice - OP goes Scandinavian initially and then Greenland with some very cold air (-12 uppers) for south eastern parts in far FI while Parallel is possibly the one for snow fans (lots of cold troughs in -8 uppers anyone?). Either way, decent for cold/snow fans. Control reprises the sliding trough from earlier in the winter further into FI with much better 850s, you;d think that would be a snow maker as well.

Parallel is the most dramatic on the 10 HPA charts with another vortex split in FI but all the charts show the PV much smaller and weaker than you would expect.

Conclusion: will we get there? Well, yes, I think so. GEM gets us to a cold evolution very quickly and if this comes off, kudos to the Canadians. GFS OP, Parallel and ECM all take a slower route but at T+240 the signs are there with upstream amplification. It looks as though we will have another cold snap at the weekend before another return to milder air this time next week which again looks as though it will be an interlude before another colder evolution at the end of the first week of next month. So a 3-4 day mild interlude followed by a 2-3 cold snap followed by another 4-5 days mild before the pattern change to a hopefully prolonged colder spell. That's how I see it looking at the models - others may see it differently.  I'd love GEM to be right but I don't see it.

[Allseasons-Si]

The ext EPS clusters are out...

cluster 3 has 46 members going for a block to our N/NE by 360

[sebastiaan1973]

Latest plume. big differences from Thursday.

[lawrenk]

18 minutes ago, tight isobar said:

Classic layer *want of align*   @10hp a worth watching=as dysfunction...reverse then ....??@dissaray..and it's nw Euro time to roll in jam !...we'll have a look at the layers and 500 pots later...so I can hopefully...make my point!!!✌

I love these posts. As a Fall fan they remind me of Mark E Smith lyrics.

[Man With Beard]

1 minute ago, Allseasons-si said:

The ext EPS clusters are out...

cluster 3 has 46 members going for a block to our N/NE by 360

It's 11 members out of 51 (member 46 chosen to represent it)

great to see 2 of the 4 clusters with the foundations for a Scandi High

[MATTWOLVES 3]

You think the latest drama with the models is a pain in the ar@e,just wait till the new warming...its looking possible in the next 7 days..and wouldn't it be nice if it went hand in hand with the earlier GFS tease...im gerrin excited again..granted it doesn't make much,but its coming folks.

Thanks to Marco P for putting these up.

[Allseasons-Si]

10 minutes ago, Man Without Beard said:

It's 11 members out of 51 (member 46 chosen to represent it)

great to see 2 of the 4 clusters with the foundations for a Scandi High

Oh yes my bad,i blame the dry eye syndrome

should of looked at the population

i am still trying to get to grips with these clusters TBH. 

Edited January 25, 2021 by Allseasons-si

[sebastiaan1973]

EC46 MJO, seems to heading 6,7.

Edited January 25, 2021 by sebastiaan1973

[Penrith Snow]

2 hours ago, northwestsnow said:

12z looks grim at 144 but still enough energy going SE to make things interesting,I hope....

Trouble is the main vortex over Greenland is closer to us than the Arctic High!

Difficult to see sustained blocking from that chart anytime soon.

Plenty of rain with snow  chances yes so I suppose it could be worse.

Andy 

[Mike Poole]

ECM clusters T192-T240 are interesting.  No big high lat heights on the first two, but both suggest a wedge - and we know at this time of year wedges mean sledges (I know that’s copyright @northwestsnow!) highlighted.  The third cluster has more substantial blocking:

All are green border -NAO!!

[feb1991blizzard]

20 minutes ago, Man Without Beard said:

*Cherry picking alert!* What's really drawn my eyes on the ECM ensembles are the members that send Sunday's low (not Saturday's) on a slight negative tilt, bringing continental air into the first front. Needs watching. Here's an example:

Yes, i thought that when i saw the 168 chart on the eps mean, doesn't have the out and out slider look but the pointy nature of the nose does suggest a decent cluster that slides

[northwestsnow]

1 minute ago, Mike Poole said:

ECM clusters T192-T240 are interesting.  No big high lat heights on the first two, but both suggest a wedge - and we know at this time of year wedges mean sledges (I know that’s copyright @northwestsnow!) highlighted.  The third cluster has more substantial blocking:

All are green border -NAO!!

I'm liking the clusters tonight Mike!

[Tim Bland]

46 minutes ago, winterof79 said:

Oh give it up I'm not arguing. Wwarm air retreating has to be good. I couldn't give a chuff who gets snow. 

I don’t want to argue either, like you I hope that we all see some snow again soon. I just know there are a lot of members who come in here for an update (who can’t interpret those charts) and didn’t want them to think there is a chance that all areas could see snow on Thursday when the reality is most will see rain, whichever model you look at.   That’s why I kept repeating that it is Pennines north as lots of posts have the impression there was chance of the mild air not making it into the Uk at all. Like I posted at 630pm it looks great for the far north. I’m sure you will do well with your altitude in Huddersfield Here’s to a lot more snow charts to come in the next few days

[sebastiaan1973]

 

[BLAST FROM THE PAST]

2 hours ago, northwestsnow said:

12z looks grim at 144 but still enough energy going SE to make things interesting,I hope....

The 00z was grim, 12z is moving in better direction I would say as per my post earlier.  More movement needed but we are in the ball park.

t144 12z

t168 00z

 

better 12z

 

 

BFTP

Edited January 25, 2021 by BLAST FROM THE PAST

[bluearmy]

18 minutes ago, Man Without Beard said:

*Cherry picking alert!* What's really drawn my eyes on the ECM ensembles are the members that send Sunday's low (not Saturday's) on a slight negative tilt, bringing continental air into the first front. Needs watching. Here's an example:

Watching the 12z run coming out and I thought to myself that this was a massive point in the way this winter would be remembered .......if that system disrupts southeast then we probably enter another week to two of wintry conditions countrywide and the ‘mild period’ becomes limited to a couple days across the Midlands and the south. If the low pushes across as per the op then it’s a week of less cold or even mild before the next trough likely drops south. if mid feb onwards does return a cool to cold as seems possible then we could be looking at two cold months.  

let’s see how the 00z handles things .....

les

[Griff]

3 minutes ago, sebastiaan1973 said:

 

Suspiciously like Matt's homework a few posts up, you're not copying each other are you boys? 

[damianslaw]

Lots of interest in the models today, in what is in my view becoming one of the most engaging winters model watching wise for a long time, with that sense all the time the atlantic is not going to have its way...

Short term - atlantic is in charge but struggling still throwing in fronts that come unstuck against weak heights to the north, low pressure forced on a more southerly track through centre of the UK and sliding SE, with colder air quickly returning from the north. Marked temp contrasts between SW and NE.

Longer terms continued signs of a more amplified flow eventually, and therefore every chance we could see a block to the atlantic allowing at last some proper cold uppers to invade the UK. I say could, not will... 

[SqueakheartLW]

I'm liking the trend just for between the 27th and 28th.

Here's the 00z GFS ensemble spread for Scunthorpe

Looks like an odds on milder spell here on the 00z for the end of the month before hints of colder weather into February

Now take a look at the 06z GFS ensemble spread for Scunthorpe

Noticed anything different. The arrow is now showing a small dip appearing early on in the milder spell although the peak of the milder spell is still around +3 at 850hpa but it appears to be taking a little longer to get milder. Is this a part of a new trend where at the last minute the milder spell gets watered down until it no longer exists, just like the one earlier in the month that went from a very mild Thursday 14th January prediction the weekend before to a cold icy rain/snow day by the time the day arrived. Wonder if that will happen again. As for after this the hints of a colder period to come are still there but with slight variations between runs and a lot of scatter later on as usual

Now lets see what the 12z GFS ensemble spread shows for Scunthorpe

Well well well. What do we see here then. An even bigger dip now showing up in the average of the ensembles between the 27th and 28th and the peak of the milder spell appears to be slightly lower at +2 at 850hpa now instead of +3. Another watering down of the milder spell yet again. Starting to question how much milder it is going to get now this week but at least the colder hints for the weekend are still there but I also see a colder trend appearing even more so into February here too.

GEM 00z ensembles for Scunthorpe

How does the GEM shape up compared with GFS. Here we have the 00z first

A definite milder spell coming up if you take the average alone but unlike GFS there is far more scatter even at this short range and that slight dip is also showing up too. What GEM 00z is showing more of though is a more definite colder spell from the up coming weekend. The Op run looks to be quite a decent run too dipping down to close to -10 at 850hpa.

GEM 12z ensembles for Scunthorpe

I'm liking what I see with the GEM even more than the GFS.

1 - The milder spell seems to have almost been completely obliterated on the average of this GEM run but a lot of scatter is still showing up.

2 - The colder spell at the weekend is still there

3 - The best part of all is the 12z operational run which once it gets cold again just gets colder and colder right to the end of the run

Some eye candy cold charts from the 12z GFS and its ensembles

My favourite one of them all to finish on