Model output discussion 25th Jan onwards

[Tim Bland]

Snow on Friday is high ground or Scotland only on this run IMO

[IDO]

Sorry off topicBut please when people state blizzards ,heavy snow ,can they state if its referring to sea level or mountains ,think this is causing serious confusion in the forum.

 

 

On this run, that cold front will be mainly rain with snow at elevation:

 

 

Early days though and much can change.

[shedhead]

Battleground scenario at T+126

 

Beautifully aligned negatively tilted Atlantic low meets the cold air - northern areas could see a bonanza

 

 

 

Rtavn1261.png

 

Rtavn1264.png

 

Rtavn12617.png

Block still not strong enough and still slightly to far east to stop the Atlantic getting through though, but it's down down to edging rather than pushing. So some snow for many, but turning to sleet and eventually rain from the west IF the 06 GFS is to be believed.

 

Edited January 26, 2014 by shedhead

[Liam J]

Sorry off topicBut please when people state blizzards ,heavy snow ,can they state if its referring to sea level or mountains ,think this is causing serious confusion in the forum.

 

The chart I posted is showing snow down to sea level for a time, look at the white thatched area - snowfall for the N half of the mainland. 

Edited January 26, 2014 by Liam J

[Stuie]

Battleground scenario at T+126

 

Beautifully aligned negatively tilted Atlantic low meets the cold air - northern areas could see a bonanza

 

 

 

Rtavn1261.png

 

Rtavn1264.png

 

Rtavn12617.png

Can`t grumble at the dewpoints @ T144   T114 either. T120 OK too.

Edited January 26, 2014 by StuieW

[Captain Shortwave]

Block still not strong enough and still slightly to far east to stop the Atlantic getting through though, but it's down down to edging rather than pushing. So some snow for many, but turning to sleet and eventually rain from the west IF the 06 GFS is to be believed.

 

Going to honest, the GFS looks like it's making a real hash of that low, it's still somehow going north east. We have heights east and north of that low and a trough in the Mediterranean. That low should disrupt and move south east, not almost stall over Scotland and wait to phase with the incoming low off the Eastern seaboard.

In other words I think the GFS is a blithering idiot

[TEITS]

.............that looks a classic easterly to me old boy! bring it on!

Are you becoming more convinced that something like this could still come off?

Let me put it this way a slider followed by a true E,ly as the block advances is W is just as likely as a mild W,ly. However at the moment im just concentrating more on +120/+144.

 

The differences between the 0Z/06Z GFS just highlights the uncertainty as did the 0Z GEFS ensembles.

[karyo]

The important thing is to focus on trends and a big positive on the 6z is that pressure is higher to the northeast. We can see a separate cell of high pressure appearing in the Svalvard area past 120 hours which joins the Scandi/Russian high and the Atlantic low does not progress northeastwards like it was in the 0z. Past 144 hours the low to our west will just be joined by the next one from the Atlantic but this detail can change.

 

Imagine if the first low is a bit shallower, it will then slide southeast and the outcome can be much better.

 

Karyo

[Bristawl Si]

 Imagine if the first low is a bit shallower, it will then slide southeast and the outcome can be much better. Karyo

Must be odds slightly in favour of "it" being a fair bit shallower, taking into acoount the GFS 'history' of producing these dartboard lows in early output.

[Catacol]

Its was almost a full house of decent model runs until the ECM turned up.poxy run, similar to the UKMO 12z yesterday-

 

I would say that its overdoing the lows depth & eastward progression-

 

S

 

Not sure which models are being looked at here... but ECM, JMA and GFS all show the atlantic breaking through on Saturday. The UKMO is a little better but we cant see the Saturday image. The GEM is out on its own showing the block holding firm.

 

ECM for Saturday:

 

then GFS also for Saturday:

 

 

Slightly better UKMO - but I dont see a retrogressing high from here:

 

 

And lastly JMA - though it is yesterday's run of course

 

 

 

The only eye candy this morning is GEM which by Tuesday has a clear retrogression of the high:

 

 

 

Sorry people. Next week trop models are now coming into line with the ECM strat profile I posted a few years ago,

 

We move onto 8 days plus now in terms of looking for cold. Fingers crossed we get a better profile to support heights.

Edited January 26, 2014 by Catacol_Highlander

[MR EXTREMES]

certainly not showing ya typical westerly onslaught often slightly below temp wise but notice the artic the heights slowly progressing towards north Greenland also anything from the nw could well be pretty chilly.

 

this week the met office has its work cut out but the azores to is possibly eventually going to recede allowing possible futher shift of systems going southeast although the heights to our east slowly shows a decline its still possible it will be stronger at t144 and perhaps beyond.

 

Edited January 26, 2014 by emotional rollercoaster

[weather eater]

Its inescapable that the GFS despite changes early on just wants to break down the block post 96hrs, but there must remain a massive uncertainty about this projection as synoptic evolutions do not stand still and it would take very little to achieve a completely different evolution as we have seen from other suites this morning, hell its only weather.

[Tim Bland]

I still believe mid - end of February will be our proper cold spell. The warning should send the PV packing ... Stratospheric temp in positive figures to our north?!

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=336&code=0&mode=10&carte=1

Edited January 26, 2014 by Tim Bland

[karyo]

Must be odds slightly in favour of "it" being a fair bit shallower, taking into acoount the GFS 'history' of producing these dartboard lows in early output.

I think so too.

[Snow Grain]

Must be odds slightly in favour of "it" being a fair bit shallower, taking into acoount the GFS 'history' of producing these dartboard lows in early output.

I wouldn't worry about that low as it will be modelled differently closer to the time.Today's wind and rain was modelled to be far more severe 5 days ago.

[bluearmy]

Not been able to post much about whats going on but beyond the 'will it, wont it' , the demise of the azores high ridging mid atlantic is just as likely to promote a euro rise in heights as a flat southerly jet. It depends what happens to the scandi ridge. We may be sitting here in 10 days wishing we still had the azores ridge - at least it would help with meridionality. Remains interesting to say the least.

[IDO]

Going to honest, the GFS looks like it's making a real hash of that low, it's still somehow going north east. We have heights east and north of that low and a trough in the Mediterranean. That low should disrupt and move south east, not almost stall over Scotland and wait to phase with the incoming low off the Eastern seaboard.

In other words I think the GFS is a blithering idiot

 

I see it different, logic says that the second possible slider should go SE, however there is no room for it to undercut. Look at the chart:

 

 

We have a Russian high, if it was a Scandi high the lows could slide under, with a Russian High the lows can only dig the upper trough deeper till it fills. This means further energy from the PV will be sucked east/NE as there is no room at the Inn. Some still leaks into the s.euro upper trough and this can only have one result, combined with the energy going east, is to push the Russian high east:

 

 

By then the surface flow has reacted to the main upper flow pushing east and we end up back in a zonal flow. The GEFS for the last few days have clustered this solution. Not an outlier solution to me.

 

GEM solves this by having the Arctic High link with the Russian High dragging the block further north and the upper trough then has room to undercut that block:

 

T180:  T240: 

 

We know if the Russian block is pushed aside FI on the GFS has been consistent with a return to zonal for the first week of Feb.

 

T384:

 

So knife edge stuff.

[karlos1983]

London

 

[Radiating Dendrite]

I still believe mid - end of February will be our proper cold spell. The warning should send the PV packing ... Stratospheric temp in positive figures to our north?! http://www.meteociel.fr/modeles/gfse_cartes.php?ech=336&code=0&mode=10&carte=1

Yes - but it does not guarantee cold for the UK.It is a little annoying this assumption that a warm start = cold bonanza. If it was that easy we would only look at strat temps and nothing else.

[swfc]

Big changes on ukmo and gfs after yesterdays dramas ete.The swiftness in change via the models leaves the door open for both big upgrade and downgrade so i guess its suck em and see atm.

[stratty]

I see it different, logic says that the second possible slider should go SE, however there is no room for it to undercut. Look at the chart:

 

 

 

.....could our LP not phase with the med one though if enough energy was heading that way?

[Paul]

Latest homepage update from Nick:

Wet & Windy Today, The A Cold And Wintry Week Ahead

[Stuie]

London

 

That looks excellent. Pleasing to see serious scatter after the 1st. That to me doesn`t look like the Atlantic piles in easily to spoil the party.

[Earth Wind and Snow]

GEFS ensembles up to + 168 and the vast majority of members are sliders in the 120-144 hour range including the control run - likely to be some stella runs in there when fully updated

 

A lot of the runs look similar to UKMO at 120 also

 

EWS

[Newberryone]

As ha already been pointed out the way things currently stand there looks to be a range of options on the table post + 96 , but there a very few options that paint a picture that includes an extension of an Easterly feed. 

 

Here IS our Easterly. 

 

 

GFS really is not interested in dropping the 2nd low some time around Friday, instead it wants it to take the same route every other Low pressure this Winter has taken and knock our block out of the way....

 

this chart is + 138 so isn't inside the reliable zone, but here's the end of the block from the GFS perspective. 

 

 

 

ECM at + 144 looks very similar

 

You can see both models want to bring in a North Westerly feed afterward with some cold air entrenched and then both models are now in agreement about flattening everything out and back to stormy conditions. 

 

It's been the trend to flatten the pattern out and put us right back where we started in December for the past 4 or 5 days now. 

 

Not welcome news for those who are looking for an end to the wet weather IMO.

 

IF THIS COMES TO PASS, then I really can't see where another shot at cold would come from.

 

Due to the ECM evolution over the past few days IMO the 2nd nail in the coffin has been firmly nailed down for Winter 2013 / 2014. 

 

let's enjoy what next week brings and hope things change over the next few days / runs. 

 

But when both the ECM and GFS fall very much in line with the Met Office's outlook for Feb, you have to admit it's not looking good after this week. 

Great post and one in which I'm inclined to agree. The main players ie Ecm and Gfs have most definitely been trending towards less ridging and overall flatter pattern being reestablished and hence a more volatile Atlantic showing its cards following next weekend.

Undoubtedly could all change in coldies favour but the way this season has played out so far leaves little room for optimism I'm afraid.

Charts that are unquestionably very reminiscent of last Dec beginning to emerge.