Model Output Discussion - 23rd Jan - 12z onwards

[Captain Shortwave]

It does look like the we will keep the cold weather until the middle of next week (even on the more progressive operationals). 

Though I have to admit, if we do see the pattern breakdown then it would sum our winter up perfectly in a way. The Siberian high has been absent for the first 2/3 of the winter but then finally builds at the worst possible time and punts the polar vortex back into the worst possible position (slap bang over the Canadian/Greenland sector).

Sometimes you just have to laugh.

 

Hopefully we will trend away from this and the ECM day 9/10 evolution does suggest a way out of the northerly which may not result in the return of westerlies. Strangely enough it's a potential repeat of the last cold spell in a way....

[Mark Parsons]

It does look like the we will keep the cold weather until the middle of next week (even on the more progressive operationals). 

Though I have to admit, if we do see the pattern breakdown then it would sum our winter up perfectly in a way. The Siberian high has been absent for the first 2/3 of the winter but then finally builds at the worst possible time and punts the polar vortex back into the worst possible position (slap bang over the Canadian/Greenland sector).

Sometimes you just have to laugh.

 

Hopefully we will trend away from this and the ECM day 9/10 evolution does suggest a way out of the northerly which may not result in the return of westerlies. Strangely enough it's a potential repeat of the last cold spell in a way....

There is some stratospheric warming over Eurasia isn't there at the moment so this would tie in with a strengthening Russian high wouldn't it? But you are right it's laughable!!

[MPG]

Taking the GFS the -5 reaches the UK shores at 57 hours, then get mixed out at 99 hours. Then returns at 135 hours but mixed out again by 144 hours. Then by 192 the pattern gets pushed east along with all coldish uppers. Not a lot of cold upper air about, lots of mixing, probably due to it being PM and not something easterly or proper northerly I guess.

 

There is no -10 Uppers in sight. This pattern is cold due to wind, but just looks like a mix of wintry showers in a strong wind, with anything settling way up at elevation. 

Edited January 26, 2015 by MPG

[Nick F]

Unfortunately the ECM is also looking flatter in FI as well with a lot of energy coming out of the eastern states, but not before some bitter weather and a few snow chances

 

ecm105.gifecm106.gifecm107.gif

 

Yep, same old problem with an intense cold trough over eastern N America and Greenland driving a strong flow downstream which eventually flattens the convoluted flow that develops by the weekend. So we get a short-lived northerly toppler as per operationals.

 

A quick glance at the 00z GEFS shows show most the members flattening out the Atlantic ridge by day 10 - which is contrast to last nights 18z GEFS which had 6-7 members either having the Atlantic high extending north to Iceland/S Greenland or the Azores high building NE across the UK/NW Europe at day 10 ... so a signal this morning that the amplified flow will not last in the first week of Feb.

 

But there is plenty of wintry potential between Weds and early next week to look foward too. Again, given the wind direction being west of north for most of the time, Scotland, N. Ireland and N England look favoured most to see snow falling and settling.

[SMU]

Yep pretty poor overnights its got to be said ( away from the mid term excitement from the UKMO et al)

 

So some potential within the week with varying degrees of intensity, & still of course the chance of upgrades down the line 192-216 although the jet allignment doesnt look ideal.

 

Chances of a greenland high almost zero.- as has been from the start, the only chance of anything sustainable is from the North East.

 

S

[Ali1977]

Slightly watered down cold spell now (as usual) although it will still feel cold Wed to Mon with potential lying snow, mainly in the North though. Not sure how cold it will be yet and if the snow that does lie will melt straight away!!

[Frosty.]

There are many more GEFS 0z perturbations prolonging the cold through next week and keeping the Azores high at bay compared to the 12z last night which only had 2 or 3 colder solutions, so..The gfs 0z op is lacking support this morning.

[nick sussex]

Morning all

 

Well the disagreement re the Euro troughing seems to be slowly resolved with the GFS moving towards the Euros, the UKMO again looks the coldest upto T144hrs.

 

As CS mentioned the PV is going to be sent westwards as the Siberian high builds which will invigorate the jet coming out of the eastern USA, the issue is how the PV reforms to the nw, a more stretched elongated sw/ne running PV could still keep the UK on the cold side, however a rounded PV to the north will effectively return the UK to milder conditions.

 

The GEM this morning holds the cold for the longest time although its less cold earlier.

 

The ECM is even more progressive this morning but leaves a snowy tease between T168 and T192hrs, the problem is whether the ECM keeps flattening the pattern out in which case that low will drop south too far east.

 

Overall still some colder weather to come with snow chances but longevity wise it looks shorter than previously suggested.

 

Ironically its the current strat warming which does the damage! effectively its done this a few times with a warming in the wrong location this winter. Unless these punches to the PV finish it off all it ends up doing is moving the PV into an unfavourable location. That's my take perhaps the more learned in terms of the strat could confirm my thoughts or tell me I'm talking tripe! lol

Edited January 26, 2015 by nick sussex

[Liam J]

Yep, same old problem with an intense cold trough over eastern N America and Greenland driving a strong flow downstream which eventually flattens the convoluted flow that develops by the weekend. So we get a short-lived northerly toppler as per operationals.

 

A quick glance at the 00z GEFS shows show most the members flattening out the Atlantic ridge by day 10 - which is contrast to last nights 18z GEFS which had 6-7 members either having the Atlantic high extending north to Iceland/S Greenland or the Azores high building NE across the UK/NW Europe at day 10 ... so a signal this morning that the amplified flow will not last in the first week of Feb.

 

But there is plenty of wintry potential between Weds and early next week to look foward too. Again, given the wind direction being west of north for most of the time, Scotland, N. Ireland and N England look favoured most to see snow falling and settling.

Such a shame Nick!! Was hoping to wake up to some upgrades this morning, you couldn't make it up! I'm off up to the Highlands next Monday for a few days and I was hopeful that the cold & snow will still be in place until at least the 5th, it was looking great yesterday! Maybe models being too progressive - wishful thinking?! 

[TEITS]

Rather than being a miserable so and so as I have been these past few days I thought I would start with a positive.

 

Latest fax for Thurs shows a series of troughs sweeping SE and I continue to believe this is the best chance for many to see snowfall.

http://www.meteociel.fr/ukmo/fax/fax84s.gif?2

 

Little to add with regards to beyond because I have made my feelings clear about this tame N,ly. The only positive is those 18Z ensembles continue to bug me and although a return to milder W,lys is the favourite I wouldn't completely rule out a massive switch to an E/NE,ly as shown by some GEFS ensembles. The GEM this morning trends towards some of those GEFS ensembles from last night before going t**s up.

[EML Network]

Yup after all the excitement and ''what if's '', the ensembles once again hold true, a cold snap of 5 days, we've even lost the attempt at a SSW event late in the run that was teasing us for a while back. 

 

If the ensembles hold true as they tend to do and if the Met Office update and some other ramblings I have heard also hold true, spring might arrive early and this winter will have been a short lived, but fairly typical one, I suspect many are going to have a snowless winter once more. 

 

I have not seen snow falling this winter, but I did wake up to a very very very slight dusting, somehow unless you see it falling it just doesn't have the same effect. 

 

Ensembles for Derby (Mid England)

Only 2 members hold out any hope of prolonged cold, I make that 10% chance of the cold remaining in place after 4th Feb. 

 

Rule of thumb , if a cold and snowy chart gets to within + 72 hours then you can start to get excited, any further out than that and you're setting yourself up for disappointment, sure you can look at the charts, discuss it, and like what you see (if it looks nice) , but always take it with a massive pinch of salt. 

I would say there's time for it to change, but I don't think there is. 



 

Edited January 26, 2015 by Paul
Removed un-needed comments

[Nick F]

Such a shame Nick!! Was hoping to wake up to some upgrades this morning, you couldn't make it up! I'm off up to the Highlands next Monday for a few days and I was hopeful that the cold & snow will still be in place until at least the 5th, it was looking great yesterday! Maybe models being too progressive - wishful thinking?! 

 

Yes, I think we can factor in an element of progressiveness from the models which could probably extend the cold for a few more days.

 

If the trop vortex didn't keep sliding in across NE Canda and Greenland and intensifying, then I think this upcoming cold spell would last that bit longer given the favourable background MJO signal which would lend to blocking to form to our NW in the Greenland and Iceland areas.

[Severe Siberian icy blast]

Yep pretty poor overnights its got to be said ( away from the mid term excitement from the UKMO et al)

So some potential within the week with varying degrees of intensity, & still of course the chance of upgrades down the line 192-216 although the jet allignment doesnt look ideal.

Chances of a greenland high almost zero.- as has been from the start, the only chance of anything sustainable is from the North East.

S

The thing that got me is we'r meant to see a dominance from the siberian vortex with the vortex heading east , as its been pointed out the strat backs this up with the strat vortex running the show but once again as near t0 the models leave more and more energy over Canada and now there's not really a split now at all , so we can't really say the strat vortex is having too much of an effect , yes we have a siberian segment which drops energy South into Europe , but plenty of energy left in the wrong place as usual and with no high lat blocking I find it very difficult to see it been more than a toppler with the cold spilling South into USA .

All these signs , that ones go on about time and time again , including from myself counts for nothing to be honest .

Edited January 26, 2015 by Severe Siberian icy blast

[bluearmy]

It does look like the second amplification is struggling which will mean next weeks reload is more marginal and we see a simpler breakdown. the second amplification was dictated by the upstream trough and also the movement of the Siberian segment vortex. all very complex. The detail between Thursday and next Tuesday looks difficult enough!

at least we can watch the GEM op to see what the cut off greeny ridge would look like though it can't sustain with the vortex headed west.

bit of a messy set of charts this morning so perhaps best to wait for the 12z's and hope for better guidance

[Frosty.]

Here are those GEFS 0z perturbations prolonging the cold spell for much of next week. When I looked at the Gfs 0z op run I wanted to reach for the sick bag but then I thought, hold on Karl, take a look at the perturbations first, so I did..and there are more than twice as many prolonging the cold compared to yesterday.

[nick sussex]

When the ECM ensembles come out and we get to see the spreads that area circled is one to watch:

 

 

If the ECM was a bit more amplified upstream we would see that low over the Low countries dropping se further west with a bit more ridging to the nw.

 

The overnight NCEP update does at least hold out some hope:

 

WPC PREFERRED GUIDANCE LEANS THROUGH THE FORECAST PERIOD WITH FLOW
EVOLUTION GENERALLY ON THE MORE AMPLIFIED SIDE OF A COMPOSITE OF
THE FULL ENVELOPE OF SOLUTIONS

 

That's upto day 7 so I'd hope that the ECM is a little too flat and might just add a bit more amplification this evening.

Edited January 26, 2015 by nick sussex

[JoeShmoe]

Yep pretty poor overnights its got to be said ( away from the mid term excitement from the UKMO et al)

 

So some potential within the week with varying degrees of intensity, & still of course the chance of upgrades down the line 192-216 although the jet allignment doesnt look ideal.

 

Chances of a greenland high almost zero.- as has been from the start, the only chance of anything sustainable is from the North East.

 

S

 

Agree Steve

 

Looks like dry and cold for most, some wintry showers on coasts and in a few favoured spots but predominantly dry with a return to something more mobile the form horse mid - long term

 

Eyes on the storm in the NE US - could be a doozy for New England ...

[West is Best]

As I mentioned earlier the jet is belting out of the eastern seaboard and it's not particularly amplified so it's bound to cause cyclogenesis like this. In the absence of upstream blocking I can't see at the moment how the northerly is going to be other than transient, and it may also get shunted further east the closer we get for the same reasons. We need a block.

 

Which is what's happening on the 0z GFS. Instead of us focusing on the northerly, look west to the low pressure system. In the absence of any real upstream blocking or amplified jet the mini ridge simply gets toppled across our shores, making the northerly itself transient.

 

 

I fear that unless there are signals for blocking and jet amplification / bifurcation this northerly will continue to become a transient affair.

Edited January 26, 2015 by West is Best

[Polar Maritime]

Ok back to what the Models are showing please, The Models show what they show,  And as ever change with each run..  

 

Thanks PM.

[The Weather Dragon]

A potent PM airmass and temporary mid atlantic ridging will deliver for a few but not for most

 

I've never seen any hint of substained blocking in the past week or so's model output 

 

Take a look at the historical charts section to see what synoptics we need for a UK wide significant cold spell

Edited January 26, 2015 by Jonathan Evans

[Jason M]

No doubting things don't look so good this morning in the mid long term, but I'd wait until this evening at least and probably longer before worrying overly. We know GEFS are often over progressive and we are talking about days 9 and 10.

Already some ugly posts this morning which does at least show some consistency from the weekend. If only the models would be so consistent.

Hopefully most will see at least some snow over the coming week or so. Hard to pin down detail at present and nothing severe but should be a bit better than last week's effort.

[The Weather Dragon]

I think that we could do with a model forum discussing output up to t120z only - would save a lot of disputes

[Hotspur62]

As others have said, this mornings models not so positive as last night and looks like it will be cold Thurs until Monday and the likelihood that it will become less cold from Tues next week onwards(Carol K indicated as much that next week not be as cold as this weekend just 25 mins ago).However,lets see where we are in 48hrs time as the Models are swinging from run to run. The main disappointment for me though is the lack of heights either in Greenland or to our North East and the models still are not showing either of these. The AH has finally moved Westwards a bit which is positive but by early next week it has the opportunity to move back Eastwards again(which it probably will do)

 

Once again it looks like our friends in North America are going to be the winners , starting with a blizzard in the NE today(Boston could be buried in upto 2 feet!!)

[West is Best]

Unfortunately the absence of upstream blocking with a flattened jet without bifurcation makes any northerly on these shores likely to be transient. It's toppler territory, at best. 

Edited January 26, 2015 by Osbourne One-Nil

[Ali1977]

It will be interesting to know if the METO still see signals for blocking Mid Feb, if so then maybe some changes to the current mid term outlook will happen.  Not much sign of this happening at the minute but with a bit of strat warming in the offing maybe the models are not seeing the bigger picture medium - long term. P9 GEFS would be a good start.

Unfortunately the absence of upstream blocking with a flattened jet without bifurcation makes any northerly on these shores likely to be transient. It's toppler territory, at best. 

Toppler territory? Is a 5-6 day cold spell classed as a toppler? 

Edited January 26, 2015 by Ali1977