Model Output Discussion 19th January 2014-18z onwards.

[Frosty.]

 

I can see the Met O outlook changing to a more wintry outlook. Have to be honest I haven't agreed with there outlook these past few days as it appears out of kilter with the model output.

well they have mogreps and we don't, they have a lot more data than we get in the public domain, so is it really out of kilter?

[Cecil Hogmanay Melchett]

well they have mogreps and we don't, they have a lot more data than we get in the public domain, so is it really out of kilter?

C;mon Frosty we have lift off now,the gefs 0z are really good,and the ecm is superb.

I hope to see meto outlook upgrade

[IDO]

There is a consensus amongst the models medium term. The Arctic high is dragged SE into Russia and the dominant block on all models at T240 is the Russian High.

 

GFS 0z mean at 168: 

 

GEM op at T210: 

 

ECM mean yesterday 12z at 216:  op today at T216: 

 

Timing and strength issues but the same LW pattern on our side of the NH.

 

As the Canadian vortex is still active, LP systems are sent SE through the UK into the s.euro trough, good confidence as the block is modelled to be very strong. The pattern is likely, with a Russian High to be too far east for snow events for many,  though the usual caveat of elevation and northern situ will help to see transient spells of snow for the lucky ones. Rain again looks the main fear for down south, colder rain no doubt. 

 

After that it depends where the Russian how migrates to. The GEFS mean at T300: 

 

This shows the Russian High again as our main block but its size shows the high spread of its movement amongst the individual members.

 

 

[winterof79]

Nice to see the UKMO and ECM agree at 144z the Arctic high moving accross the pole to reinforce heights to our East

http://www.meteociel.fr/ukmo/runs/2014012100/UN144-21.GIF?21-06

http://www.meteociel.fr/modeles/ecmwf/runs/2014012100/ECH1-144.GIF?21-12

Leading to

http://www.meteociel.fr/modeles/ecmwf/runs/2014012100/ECH1-240.GIF?21-12 That is a beast of a high and still heights to the north.

And it is not even the end of Jan.

Short term i am interested in Fri/Sat developing into a battle over the Spine of the UK

Edited January 21, 2014 by winterof79

[bluearmy]

bit concerned about how quickly the arctic high is cut off from the other side on ecm this morning. i think thats why the low clears slowly without a decent flow behind it. could do with a good build of heights to push the cold west. anyway, better overall and good to see the spreads from last night illustrated on the following op.

[Cecil Hogmanay Melchett]

bit concerned about how quickly the arctic high is cut off from the other side on ecm this morning. i think thats why the low clears slowly without a decent flow behind it. could do with a good build of heights to push the cold west. anyway, better overall and good to see the spreads from last night illustrated on the following op.

First step is the Atlantic retrograde BA-

Once/if that happens all doors to cold open....

[shedhead]

Just as it was unwise yesterday to scream Winters over on the back of one run, it's equally unwise this morning to assume Snowmamadden is imminent, both are off the mark. What we have witnessed across the last 24hrs is typical winter model variation in the T+120hr range and as the coming few days unfold I think we can expect a lot more of the same, but on balance it does look as though some sort of 'colder' spell is more likely than not by this time next week. Exactly how it manifests itself, how deep it is and what longevity it manages to achieve remains very much open to question however, but as ba said the overnight ECM profile is not good for sustained cold. 

[Severe Siberian icy blast]

bit concerned about how quickly the arctic high is cut off from the other side on ecm this morning. i think thats why the low clears slowly without a decent flow behind it. could do with a good build of heights to push the cold west. anyway, better overall and good to see the spreads from last night illustrated on the following op.

Yes I agree , I think ideally we need the massive high to migrate west somewhat , but even as it is if you look at the last chart on the ECMNot that it would look like that come the time , but the low pressure system to south of Greenland the only way for that to head is south east , with cold uppers in place that would be high reward although risky I would say . I'm encouraged by the strength of the high , it's mighty and strong and that really would dictate the pattern , and it's an evolving pattern that starts at t144 so the building blocks are in place for a very different pattern going into February . Not immediate cold and snow but a building block going forward .

[Frosty.]

According to the Ecm 00z op run, the atlantic v scandi cold block will be fighting / slugging it out for the next 7-9 days with each having the upper hand at various stages although i'm pleased the cold eventually wins with an icy / frosty spell to end the month...we get free ring side seats to this potentially epic encounter,

[MR EXTREMES]

morning everyone well well well this time there is potential and there seems to be cross models agreement and the other models even the ecm have followed lastnights jma honestly its now or never for this cold to come.

[lorenzo]

The fun output continues.. some fantastic posts last night, a really good read.

 

All of the 'Big 4' or Big 3 plus it's mate who is due an upgrade, go for a nice separation of that low from the mean Canadian troughing at around 144. Also the NPAC ridge is back in play where it had dwindled for 24 hrs or so, Sunday > Monday.  

 

ECM / GEM / GFS / UKMO

 

 

ECM Mean / Anomaly

Day 10 still showing anomalous heights over the polar field and distinct separation of vortices, also a strong Russian High, a world away from where we were a couple of weeks ago.

 

Whilst, the MJO is a little scrambled, looks like the in situe activity over the maritimes and Kelvin Waves are proving enough to deliver a response in the background state. The latest CPC weekly bulletin explains the mixed MJO and KW signal.

 

Interestingly, the UKMO and ECM are pretty bullish here re: Phase 7 placing MJO into that phase for a week or so, JMA, as noted off,into Phase 8, GFS and GEFS spinning in Phase 6, net average some Phase 7 influence if the UKMO and ECM conitnue to trend this way. More potential for Greenland heights, intriguing if this can pull through with dwindling vortex vorticity in that vicinity! Try saying that without a coffee..

 

Totally understand the frustration as this chase may be one step too far for some folks, battered into submission by the coldest vortex in the last 30 years or so and a raging Atlantic jet, but Winter over, nope. Winter just beginning...

 

[bluearmy]

And the ec32 mean - as you were after the next 10/14 days. Probably even more decemberish than recent runs with the Azores pushing ino Europe.

[chionomaniac]

The fun output continues.. some fantastic posts last night, a really good read.

 

 

Interestingly, the UKMO and ECM are pretty bullish here re: Phase 7 placing MJO into that phase for a week or so, JMA, as noted off,into Phase 8, GFS and GEFS spinning in Phase 6, net average some Phase 7 influence if the UKMO and ECM conitnue to trend this way. More potential for Greenland heights, intriguing if this can pull through with dwindling vortex vorticity in that vicinity! Try saying that without a coffee..

 

Totally understand the frustration as this chase may be one step too far for some folks, battered into submission by the coldest vortex in the last 30 years or so and a raging Atlantic jet, but Winter over, nope. Winter just beginning...

Hi Tony

 

Did you ever get around to completing composites for Feb?.

 

If I remember correctly the phase 7 MJO has a flattened Azores ridge so we would like to push through to phase 8 - otherwise the carrot may be left dangling!

[MR EXTREMES]

The fun output continues.. some fantastic posts last night, a really good read.

 

All of the 'Big 4' or Big 3 plus it's mate who is due an upgrade, go for a nice separation of that low from the mean Canadian troughing at around 144. Also the NPAC ridge is back in play where it had dwindled for 24 hrs or so, Sunday > Monday.  

 

ECM / GEM / GFS / UKMO

ECM 00z.gif GEM 144.pngGFS 144.pngUKMO 144.gif

 

ECM Mean / Anomaly

Day 10 still showing anomalous heights over the polar field and distinct separation of vortices, also a strong Russian High, a world away from where we were a couple of weeks ago.

EDH1-240.gifEDH101-240.gif

 

Whilst, the MJO is a little scrambled, looks like the in situe activity over the maritimes and Kelvin Waves are proving enough to deliver a response in the background state. The latest CPC weekly bulletin explains the mixed MJO and KW signal.

 

Interestingly, the UKMO and ECM are pretty bullish here re: Phase 7 placing MJO into that phase for a week or so, JMA, as noted off,into Phase 8, GFS and GEFS spinning in Phase 6, net average some Phase 7 influence if the UKMO and ECM conitnue to trend this way. More potential for Greenland heights, intriguing if this can pull through with dwindling vortex vorticity in that vicinity! Try saying that without a coffee..

 

Totally understand the frustration as this chase may be one step too far for some folks, battered into submission by the coldest vortex in the last 30 years or so and a raging Atlantic jet, but Winter over, nope. Winter just beginning...

good post and its been awful but finally I might be able to pick my toys up and put them back into there pram theres no question there is a pretty good cross model agreement this morning but since my tantrum sunday night all has slowly progressed in a slightly more positive direction.

ecm offers reloads of ne flow and cold gathering pace into Europe thanks to the scandi block.

[nick sussex]

A better start to todays outputs with at least hints that there will be a separation of low heights upstream, the best of the big 3 is the ECM because it develops a shortwave at T144hrs upstream over the USA plains, as this runs se it helps to pull back the PV and ejects some weaker energy se at T168hrs.

 

If you notice on the GFS a shortwave develops much later and near the east coast and you can see how much of the PV moves out into the Atlantic at 168hrs, the UKMO is similar to the GFS, with no developed shortwave in the USA plains at T144hrs.

 

Small things matter here especially in the context of trying to get a decent clearance of low heights which have been attached to low pressure near the UK for what seems like weeks.

 

Just to clarify, both the GFS/UKMO have very weak shortwave energy but the failure to develop this hinders the possibilities of keeping more energy back over the USA, in the ECM this will phase with the PV chunk on its southern flank, this causes a north/nw push of the PV chunk.

Edited January 21, 2014 by nick sussex

[MR EXTREMES]

A better start to todays outputs with at least hints that there will be a separation of low heights upstream, the best of the big 3 is the ECM because it develops a shortwave at T144hrs upstream over the USA plains, as this runs se it helps to pull back the PV and ejects some weaker energy se at T168hrs.

 

If you notice on the GFS a shortwave develops much later and near the east coast and you can see how much of the PV moves out into the Atlantic at 168hrs, the UKMO is similar to the GFS, with no developed shortwave in the USA plains at T144hrs.

 

Small things matter here especially in the context of trying to get a decent clearance of low heights which have been attached to low pressure near the UK for what seems like weeks.

so here we go shortwave on nightmare street part 6 lol.

but I do agree nick and you been right through out this winter so far with your shortwave explanation so lets hope to see what you have questioned in future runs.

 

but over all its certainly gathering pace now coming closer to lets get this all into the t96 area then we might have something to smile at.

[Frosty.]

I hope shortwaves don't scupper our chances of our first cold spell of the winter, just in case I will keep listening to bbc radio 4 longwave for those excellent forecasts.

[nick sussex]

so here we go shortwave on nightmare street part 6 lol.

but I do agree nick and you been right through out this winter so far with your shortwave explanation so lets hope to see what you have questioned in future runs.

 

but over all its certainly gathering pace now coming closer to lets get this all into the t96 area then we might have something to smile at.

Thanks, I'd say this shortwave is important but not like a Scandi one where everything rests on its outcome, without the deeper shortwave you can still end up with some cold but its more difficult to get that clean break with upstream energy.

 

I'd advise everyone to look at the NH perspective and take the 144hrs and 168hrs of the GFS and ECM and see just how the shortwave effects the PV.

 

We wouldn't have to worry so much about the shortwave if the Azores high was more amplified, this would then delay the next energy spilling east out of the USA.

Edited January 21, 2014 by nick sussex

[Troubleatmill]

A better start to todays outputs with at least hints that there will be a separation of low heights upstream, the best of the big 3 is the ECM because it develops a shortwave at T144hrs upstream over the USA plains, as this runs se it helps to pull back the PV and ejects some weaker energy se at T168hrs.

 

If you notice on the GFS a shortwave develops much later and near the east coast and you can see how much of the PV moves out into the Atlantic at 168hrs, the UKMO is similar to the GFS, with no developed shortwave in the USA plains at T144hrs.

 

Small things matter here especially in the context of trying to get a decent clearance of low heights which have been attached to low pressure near the UK for what seems like weeks.

 

Just to clarify, both the GFS/UKMO have very weak shortwave energy but the failure to develop this hinders the possibilities of keeping more energy back over the USA, in the ECM this will phase with the PV chunk on its southern flank, this causes a north/nw push of the PV chunk.

 

Yes Nick, looking at the GEFS postage stamps at t240, we cant seem to get a window! as if its a rinse and repeat, although on the whole its edging in right direction bit by bit i.e west and this is showing on the ensembles

Edited January 21, 2014 by Nicholas B

[Nick F]

00z EC alot keener to break down the NE Pacific ridge than GFS looking at the H500 anomalies, not sure what impact this will downstream over Canada/N Atlantic sector, perhaps help retrograde the PV segment over NE Canada and allow the Azores ridge north as per 00z EC deter?

 

All to play for still with around 50% of the GEFS going for a cut-off low over mainland Europe with an E/NE flow by days 7-8 and support from the 00z EC operational. Still the potential spanner in the works wrt to too much energy spilling down from the NW courtesy of the strong temp gradient over the NW Atlantic sector under our old foe the PV segment over NE Canada, which may move, if the NE Pac ridge breaks down.

[R.P. McMurphy]

Morning all,

 

Some decent charts this morning from the ECM into FI - Looking at the more reliable, some decent looking snow maps too:

 

 

 

Thursday could be the first snow we have seen all Winter & we should be watching these developments with a keen eye !

[nick sussex]

00z EC alot keener to break down the NE Pacific ridge than GFS looking at the H500 anomalies, not sure what impact this will downstream over Canada/N Atlantic sector, perhaps help retrograde the PV segment over NE Canada and allow the Azores ridge north as per 00z EC deter?

 

All to play for still with around 50% of the GEFS going for a cut-off low over mainland Europe with an E/NE flow by days 7-8 and support from the 00z EC operational. Still the potential spanner in the works wrt to too much energy spilling down from the NW courtesy of the strong temp gradient over the NW Atlantic sector under our old foe the PV segment over NE Canada, which may move, if the NE Pac ridge breaks down.

Thats quite ironic considering it was previous GFS runs that wanted to break that down too soon, reading NCEP comments I think this is now a race against time to get the cut off low se of the UK before the ridge breaks down.

[mulzy]

THe ECM ensemble mean more progressive than the operational at days 9 and 10.

 

 

[winterof79]

Thanks, I'd say this shortwave is important but not like a Scandi one where everything rests on its outcome, without the deeper shortwave you can still end up with some cold but its more difficult to get that clean break with upstream energy.

 

I'd advise everyone to look at the NH perspective and take the 144hrs and 168hrs of the GFS and ECM and see just how the shortwave effects the PV.

 

We wouldn't have to worry so much about the shortwave if the Azores high was more amplified, this would then delay the next energy spilling east out of the USA.

Hi Nick,

The GEM develops it to some extent too http://modeles.meteociel.fr/modeles/gem/runs/2014012100/gemnh-0-168.png?00

 with a different outcome albeit still cold

http://modeles.meteociel.fr/modeles/gem/runs/2014012100/gemnh-0-240.png?00

http://modeles.meteociel.fr/modeles/gem/runs/2014012100/gemnh-1-240.png?00

[Nick F]

Thats quite ironic considering it was previous GFS runs that wanted to break that down too soon, reading NCEP comments I think this is now a race against time to get the cut off low se of the UK before the ridge breaks down.

 

So do you reckon the break down of the NE Pac ridge won't work in our favour Nick? I agree that we need that low to cut-off quickly from the Altantic flow over Europe before the next re-surgence of energy from the northwest tries to keep us locked in to the same pattern. Though our fortunes may, for once this winter, work in our favour, with upstream playing ball. Still worried about the flow upstream being too strong though.