Model output discussion - is the beast awakening?

[Mike Poole]

1 minute ago, sheikhy said:

Well if ecm is the worse outcome at 72 hours with that low over the uk just imagine how much on an upgrade it would be if it was to go further south in future runs!!

Be careful.  The best outcomes are always from high risk high reward situations, the safe scenarios don’t generally deliver anything spectacular. We are in one of those high risk high reward scenarios right now. 

[bobbydog]

Just now, ICE COLD said:

Speaking of the 1991 feb blizzard where is @feb1991blizzard thought he would be booming the runs tonight . 
 

ECM T144 to T240 in unbelievable great

He's just checking how to change his username to 'feb2021blizzard'.... 

[Phil Blake]

5 minutes ago, WINTRY WALES said:

What I don’t understand is why don’t fronts push from east to west at all?? Always reach midlands at best in an easterly...well mostly 

Same with fronts coming in from West usually. Not just with snow. The Pennines take alot of the precipitation and turns more patchy for the north east. 

[sheikhy]

The ecm mean is on a different planet!!!cant believe what im viewing this evening!!

[ICE COLD]

Wow the mean is a snorter

144 and 168 

[sheikhy]

1 minute ago, ICE COLD said:

Wow the mean is a snorter

144 and 168 

I see the beast has begun ice cold as you have started using these lovely 850 charts already!!

[JoeShmoe]

The problem with that ECM run is it’s like being shown a ribeye steak and getting a  burger. Would be nice but it will never evolve to being that good (if we’re honest we all know that right !). Having said that even downgrades from there would still be very good .. 

[Mike Poole]

ECM mean T144, and this has got to be good:

Uncertainty distorts the picture later on so will wait to see the clusters before making comment on the later evolution.

[Singularity]

Main thing of note to me of the 12z runs is the coming together on sending some cold air down west of Iberia which then initiates a typical sequence of development and northeast movement of the trough there.

Due to starting so far south it has a good chance of being east of us by the time it’s far enough north for the warm sector to reach the latitude of the south coast.

BUT it’s essential that the low over the UK beforehand is in the dissipation stage by the time that low to the south makes its move. Then it unravels into the circulation and the very cold air cuts in behind.

The GFS 06z failed to do that. On the other hand, the GEM 12z didn’t, despite having the strongest low on the preceding Friday, which really strains the logic...!

Edited February 1, 2021 by Singularity

[john mac1]

10 minutes ago, sheikhy said:

Well if ecm is the worse outcome at 72 hours with that low over the uk just imagine how much on an upgrade it would be if it was to go further south in future runs!!

That’s the thing, still room for upgrades at close range. 

[stodge]

Evening all

Apologies for yesterday evening - my usual time to consider the evening model output was cut short. Unfortunately tonight you'll have to wind through my nonsense to the next burst of "winter is over" or "there's no point sugar coating it, it's a massive downgrade" or "it's only -12 uppers, we only got snow in my area if it's -14 uppers so it's cold rain for me" or the other troll-infested nonsense.

Those who are still with me after that little rant - the worry again last night was ECM which kept too much energy in the north and north west to allow a smooth trough disruption south  and allow the orthern heights to introduce the easterly. Still, as a wise man once said "that was then but this is now".

T+120 takes us to Saturday February 6th

12Z GEM: quite a change to the evolution this evening suggesting we still haven't nailed this down even at T+120. The trough currently to the west and north west has filled and moved east to be over the North Sea. Heights to the north have developed over Greenland and have halted the LP coming out of North America forcing it back east or east south east while the Mediterranean is covered by abroad but shallow trough emanating from North Africa. Colder air has returned with 850s between -4 and -8 across the British Isles. From there, the strong push of heights from the north has pushed the trough south and by T+180 ot sits over southern and eastern England as an elongated shallow feature with an E'ly persisting to the north. Heights persist upstream at this time. 850s below -8 over much of northern Britain by this time but less cold air very close to the Channel coast so pick your snow line. From there, the cold spell quickly breaks down - the trough moves east but a shortwave forms and become vital in preventing a new build of heights from the Azores to Scandinavia. Instead, the Azores HP ridges into Iberia and pulls up a much milder SW'ly air flow by T+240. By then, positive uppers are back over western and northern parts and 850s are slightly negative further east with milder air encroaching.

So it's a 5-7 day cold spell only on GEM before the Atlantic comes back. The PV looks to be making a come back as well so all in all a disappointing run for cold fans.

12Z GFS OP - the best of the bunch last evening. At T+120 this evening everything looks on track with the LP now over northern Spain and an E'ly across the British Isles. 850s of -8 or below from the Midlands north and from -4 to -8 further south.  From there, the trough starts to come back NE towards southern Britain hovering close to the south east as a potential snow maker (you'd think). At T+180 the trough is now an elongated feature covering much of the continent with an ENE'ly flow across the British Isles on its northern and western flank. Uppers below -8 over the whole British Isles and below -12 over eastern Scotland so a tad brisk for many. With heights from Greenland pressure falls from T+180 to the north and north east of the British Isles with a series of secondary LP forming and moving south or south east. By T+240 the trough extends from one centre to the east of the Faeroes south and east into Europe while a new Atlantic LP is approaching with energy looking to phase with the existing trough and head south east into Europe. Uppers remain below -8 over most of the British Isles with some slightly less cold air to the south west. 

A superb run for cold and snow fans with lying snow over many parts if this verifies.

12Z Parallel - more progressive than the OP in recent days but still decent in the end though not food for the nerves. If I'm being honest, the T+120 looks a compromise between OP and GEM. The trough has been slower to sink south and it has phased with the trough coming north out of Africa. The E'ly is in across the north but has only just reached the south by this time. Uppers of zero to -4 over much f southern and south western Britain and Ireland with 850s below -8 over northern Scotland. From there, the trough moves back NE as it does on the OP to be over or close to south-east England by T+180 with an ENE'ly flow over most of the British Isles. A second GEM has moved SE towards Iberia with heights persisting to the north west. Uppers below -8 cover the whole of the British Isles by this time. Moving on, the trough eases SE towards Northern Italy and weak heights build over southern Scandinavia south west as a new Atlantic storm extends energy east but with a hint of negative alignment as it moves toward the block and cold pool by T+240. Calm conditions over most of the British Isles by this time. Less cold air has reached Ireland with a SW'ly flow picking up but uppers remain below -8 over most of the British Isles and below -12 over East Anglia.

Not quite as good as GFS OP (that would have been difficult) and we'll see where it goes after T+240 but certainly plenty for cold and snow fans.

12Z ECM: - leaving the worst to the last I would guess - ECM has refused to play ball with the cold spell thus far. Will it fall into line or stand tall and proud? At T+120 it's all happening a bit more slowly than with GFS with the trough still over Britain though phased with the new LP over Iberia. Heights are trying to push south but the E'ly is only over Scotland by this time. Uppers of -4 to -8 over the British Isles by this time. Now the crucial bit - the trough does sink south and heights develop over Scandinavia leaving an E'ly over the British Isles with the LP just off Cap Finisterre by T+192. Uppers below -8 everywhere and below -12 over East Anglia and eastern Scotland. From there, the trough fills  but remains close to south east England as heights continue to build over Scandinavia but not well oriented at T+240. An Atlantic trough is approaching slowly but still well to the west. Uppers still below -8 by T+240 with a push of -12 uppers over south east England by T+240.

A significant turn round from ECM tonight moving in the medium term to the GFS leaving the GEM looking isolated at T+240. 

Moving on, the T+312 (Feb 14th) and T+384 (Feb 17th) charts from OP and Parallel respectively:

Both break down the cold spell in far FI - OP tries to build heights into Scandinavia while Parallel ends almost spring-like with +8 uppers and a large HP over Europe. Control also ends milder and more anticyclonic. UKMO looks fine but JMA doesn't and along with GEM fail to develop the cold spell.

Conclusion: we're almost there but we're not. It's good to see the main models all looking very similar at T+120 but GEM and JMA aren't on-side yet and that's a worry even at this distance. GEM is disappointing while both ECM and the GFS models look excellent at T+240. The indications are it will be a 7-10 day cold spell and quite severe for many - prolonging it further seems to rely on height rises over Scandinavia and to be fair we don't always see the strength of the Scandinavian block in early modelling where the bias is to being back the Atlantic but that relies on a powerful PV and an active zonal jet. It remains to be seen if the PV has enough strength this year to break down any Scandinavian block or whether it may be an opportunity to build far enough west to keep the British Isles either cold and dry or in the battleground.

 

[johnholmes]

No pc mid day fri 29 jan-mid day mon 1 February 2021

ec-gfs for mon 1 feb and noaa 31 jan eve

ec-gfs both shows simila flow from e Russia into e’ern n America but differences in how they treat the trough in that area and also into atlantic they differ, ec shows no sign ridging which gfs does into Iceland/Greenland, nor does ec have any troughing into Europe which gfs has

noaa far w lost its marked ridge west of w coast, main n anerica trough is now well e of position e days ago, higher value +ve heights e’ern Canada, some kind of troughing e from this area with ridging over top of it w’wards(!), still v little flow over uk, what there is showing n of w minor troughing into Europe and now little signal for +ve heights s’ern Europe or ridging from azores, both showed on fri chart; 8-14  is again developing the far w ridge with the troughpushing it west of this also reasonably marked; both too far w, in my opinion at the moment, to cause any marked trough/ridge development downwind, there is some contour signal for diging not totally different to gfs with a then fairly flat rather slack w’ly into the uk on this chart.

This post is simply a holding/information set of data from various 6-10 day charts for me having had no access for 3 days.

Differences in the various outputs suggest there is not final decision in the later stages of the 6-14 day weather yet, other than it does look to be a cold rather than a mild outlook.

Ecmwf charts

a)     for period 7-11 feb initial marked troughing from ne almost flattened out in period:still fairly complex surface low wnw-ese atlantic into nw Europe; -5 c 850 mb over whole uk retreats away back to borders in period

for 1-11 feb inc shows 850 mb values start >0 C far sw England and wales, by about 8/9 th it has -5 and below from thames up to  n Ireland, the -10 almost into e Scotland, by the 10th the coldest air is back around the Scottish border.

 

Being out of the loop for 3 days it is not easy to see where the probable thrust is coming beyond day 10 to me. So I will have to see another couple of days before I feel confident in what seems most likely.

These are ECMWF 500 and surface charts on this link

http://www2.wetter3.de/Fax/00_ECMWF_ENS_p0_500hPa+144_240.gif

and another link into ECMWF charts

http://meteocentre.com/numerical-weather-prediction/

 

ECMWF/GFS DAY 8-10 MEAN 500MB HEIGHT COMPARISON

WWW.METEO.PSU.EDU

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

[MATTWOLVES 3]

First sign of a downgrade perhaps...get out of here...the op is higher resolution so its onto something.. That mean is still solid though and I'm expecting it to drop down.

Rock solid like Mike Poole so rightly says out through next week with good agreement from both the op and mean of it being very much colder..even beyond the cold theme looks to extend.. Im very happy with the output....forget about downgrades,I'm expecting another boom moment from the 18s.

Edited February 1, 2021 by MATTWOLVES

[phil nw.]

Well the path to bitter cold continues.I think we will all feel more comfortable once that slow moving low eases into the continent.

Nationwide snow and cold again modeled from the weekend and into next week but just that little fly in the ointment to clear up.

Back to the neartime and i thought a look to closer developments and this evening's t72 fax and raw 850's from the met

WE can see the depth of cold over Scandinavia and areas to our north which has been lurking and building for what seems like weeks now.The far north never really clear of it and all that cold waiting for the trigger low showing across the centre of the UK to move aside to open the flood gates.

If things go as medium term modeling shows then we should all be in for a notable cold and snowy spell nationwide with the battleground headed south of the channel.

Chart watching at it's best.

Edited February 1, 2021 by phil nw.

[Mike Poole]

Just now, MATTWOLVES said:

First sign of a downgrade perhaps...get out of here...the op is higher resolution so its onto something.. That mean is still solid though and I'm expecting it to drop down.

Yes, Matt, but the op was such a ridiculously cold run that it had to be an outlier on the mean. I think the middle part of that plot is more telling - consistency towards cold.  Reliable on ensembles is generally a couple of days longer than the ops so is good to see.

[That ECM]

7 minutes ago, johnholmes said:

No pc mid day fri 29 jan-mid day mon 1 February 2021

ec-gfs for mon 1 feb and noaa 31 jan eve

ec-gfs both shows simila flow from e Russia into e’ern n America but differences in how they treat the trough in that area and also into atlantic they differ, ec shows no sign ridging which gfs does into Iceland/Greenland, nor does ec have any troughing into Europe which gfs has

noaa far w lost its marked ridge west of w coast, main n anerica trough is now well e of position e days ago, higher value +ve heights e’ern Canada, some kind of troughing e from this area with ridging over top of it w’wards(!), still v little flow over uk, what there is showing n of w minor troughing into Europe and now little signal for +ve heights s’ern Europe or ridging from azores, both showed on fri chart; 8-14  is again developing the far w ridge with the troughpushing it west of this also reasonably marked; both too far w, in my opinion at the moment, to cause any marked trough/ridge development downwind, there is some contour signal for diging not totally different to gfs with a then fairly flat rather slack w’ly into the uk on this chart.

This post is simply a holding/information set of data from various 6-10 day charts for me having had no access for 3 days.

Differences in the various outputs suggest there is not final decision in the later stages of the 6-14 day weather yet, other than it does look to be a cold rather than a mild outlook.

Ecmwf charts

a)     for period 7-11 feb initial marked troughing from ne almost flattened out in period:still fairly complex surface low wnw-ese atlantic into nw Europe; -5 c 850 mb over whole uk retreats away back to borders in period

for 1-11 feb inc shows 850 mb values start >0 C far sw England and wales, by about 8/9 th it has -5 and below from thames up to  n Ireland, the -10 almost into e Scotland, by the 10th the coldest air is back around the Scottish border.

 

Being out of the loop for 3 days it is not easy to see where the probable thrust is coming beyond day 10 to me. So I will have to see another couple of days before I feel confident in what seems most likely.

These are ECMWF 500 and surface charts on this link

http://www2.wetter3.de/Fax/00_ECMWF_ENS_p0_500hPa+144_240.gif

and another link into ECMWF charts

http://meteocentre.com/numerical-weather-prediction/

 

ECMWF/GFS DAY 8-10 MEAN 500MB HEIGHT COMPARISON

WWW.METEO.PSU.EDU

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

Hi John. Why is there a spike in the green line near to us? I’ve not seen this before. TIA

[Cavehill Snow]

1 hour ago, Mike Poole said:

ECM T240, this just the most incredible run I’ve seen, beats last night’s pub run and that is saying something:

You need to re-draw your direction arrow on the 240hrs pressure chart a little further south than shown, then you would score a perfect 10 for artistic merit.

[TSNWK]

6 minutes ago, MATTWOLVES said:

First sign of a downgrade perhaps...get out of here...the op is higher resolution so its onto something.. That mean is still solid though and I'm expecting it to drop down.

That will do.. pretty much on the mean until day 7 which to my mind supports the 1st phases have decent creditabilty.. splits away on its merry way day 8 but that’s fine for now we can work on that..:)

[Battleground Snow]

ECM weekly  Whooosh!

Weeks 1,2 and 3

 

[kold weather]

Strong agreement on the ECM ensembles for the easterly coming in.

Thats not to say all the runs go for a easterly mind you, some struggle to move the LP out of the way quickly enough before its absorbed into the broader flow which prevents much of a cold air push. However even those runs are not without interest as most of them bring a marginal snow event up from the S/SW.

Overall though a solid set of ensembles.

[stodge]

7 minutes ago, Singularity said:

Main thing of note to me of the 12z runs is the coming together on sending some cold air down west of Iberia which then initiates a typical sequence of development and northeast movement of the trough there.

Due to starting so far south it has a good chance of being east of us by the time it’s far enough north for the warm sector to reach the latitude of the south coast.

BUT it’s essential that the low over the UK beforehand is in the dissipation stage by the time that low to the south makes its move. Then it unravels into the circulation and the very cold air cuts in behind.

The GFS 06z failed to do that. On the other hand, the GEM 12z didn’t, despite having the strongest low on the preceding Friday, which really strains the logic...!

I confess the evening models generally look very good but I'm still concerned.

JMA goes wrong here:

The phasing of energy from north and west prevents the trough exiting cleanly to the south and we get stuck with LP close to or over the British Isles.

GEM isn't too bad at T+180 but fails because the trough orients poorly and then stops the Scandinavian heights spreading south west towards the British Isles - that failure allows the Iberian HP to build in, the trough aligns positively and we're stuffed.

These are nitpicks but a concern. Have to say, the ECM Control is a thing of beauty keeping the south cold or very cold right through to T+360.

[WorldExplore]

... Beasterly ...

Gulp Gulp

[TSNWK]

Just now, Battleground Snow said:

ECM weekly  Whooosh!

Weeks 1,2 and 3

 

Omg it’s relentless I forgot that Monday’s and Thursday have the weeklies as a Brucey bonus between ecm mean and the start of the 18z suite......

[Mike Poole]

Clusters!!

T120-t168:

My take:

Cluster 1, troublesome low seeps away SE and allows clean easterly to develop. 21 members.

Cluster 2, troublesome low remains annoying. 18 members.

Cluster 3, troublesome gone south early, undercut of next one,  maybe a bit like GFS, 12 members.

But, and here’s the thing, it is not at all clear to me which would bring the best longer term cold prospects.  

 

[Crackerjack]

1 hour ago, Lampostwatcher said:

Gfs 12z sonic boooom ❄❄

UKmo 12z  sonic boooooom ❄

Ecm 12z sonic boooooom ❄❄

 

You wouldn't think I'm in my mid 40s

Excited

Budge over mate I’m mid 50’s and I’m already checking my Fitbit pulse rate which is increasing by the hour