Model output discussion 25th Jan - The final third of winter beckons..

[Summer Sun]

34 minutes ago, seaside 60 said:

Why is this being shown, all it does is show half the picture and shows the Atlantic, not even all of the UK and nothing east of us, just because most of our weather comes from the west, most of the weather this autumn and winter it hasnt.
Its pretty pointless and really does nothing to add to the model conversation.

 

Well it's a chart and it can still show a colder set up should we get one even if it doesn't show the east

[seaside 60]

1 minute ago, Summer Sun said:

Well it's a chart and it can still show a colder set up should we get one even if it doesn't show the east

This has I am sure been asked before.
However can you kindly refresh my memory.
Why does the UKMO model show this but doesnt go beyond 144hr over our territory.

[blizzard81]

22 minutes ago, bluearmy said:

Looks OK to me 

the low becomes a disrupted trough over holland and much of the energy in the system disrupts se into the med (which is why it only gets as Far East as holland) 

I will agree to differ with you on this one. The dive south east looks way too rapid to me.

[Summer Sun]

Just now, seaside 60 said:

This has I am sure been asked before.
However can you kindly refresh my memory.
Why does the UKMO model show this but doesnt go beyond 144hr over our territory.

 

I suspect it's something to do with licensing meteociel used to have the 850's for UKMO but they became unavailable a few year back

[bluearmy]

3 minutes ago, seaside 60 said:

This has I am sure been asked before.
However can you kindly refresh my memory.
Why does the UKMO model show this but doesnt go beyond 144hr over our territory.

It's a global model

its just that they don't release the data fro day 7  freely

probably feel it would devalue the product as reliability would tail off 

[Summer Sun]

 

[Allseasons-Si]

1 minute ago, feb1991blizzard said:

TBF though that wont have smelt the coffee yet, that's yesterday's 6z, so that's 5 runs behind where we are with the regular GFS.

You absolutely right there feb,few,TFFT,maybe it's me that should smell the coffee lol

anyway,the latest ensembles,a slight downward trend but nothing too significant yet,they do show the latest dates

http://www.weerplaza.nl/15daagseverwachting/?type=eps_pluim

http://projects.knmi.nl/exp/pluim/vijftiendaagse/index.php?run=12

noaa 8-14 days,i think show the trough digging further SE,look at all the height's in Russia/Scandinavia

18z starting now.....rubbing hands

[Summer Sun]

The ECM monthly issued this morning shows temperatures close to or above average for Feb

Let's see what the EC Monthly comes up with shortly

[chris55]

ECM 12z Deblit

spot the trend setter .......  

[SMU]

Early doors on the 18z & a swift move to the UKMO solution over NE scandi

Before then after ...

[Allseasons-Si]

while the 18z is rolling out i am just toying around with the charts from today at 144 hrs compared to yesterdays 168hrs

gfs

ecm

gem

ukmo

Clearly you can see that today's 12z has better ridging of the hp into the pole and more of a neg tilted trough around the eastern side of the block.

Edited January 30, 2017 by Allseasons-si

[Allseasons-Si]

20 minutes ago, Steve Murr said:

Early doors on the 18z & a swift move to the UKMO solution over NE scandi

Before then after ...

Yep Steve,more of an easterly component at 132 than a SE that should slice/sheer the lp further SE and slightly better height's too over N scandi.

although,not to be on this run,too much energy running NE and the azores is high pushing in,still it's only one run and there will be plenty of up's and down's come this week.

Edit:

Wait,i will take back what i just said there,it is still looking good,just a bit longer than the 12z.

Edited January 30, 2017 by Allseasons-si

[booferking]

This run more in line with ECM in the latter.

[Ali1977]

Eastern Europe getting another big freeze there way, they've had a very cold winter that's for sure. Great to have split the PV but too far East to effect the UK so far.

Day 9 and still a decent looking chart, cold air could start heading west but ideally need to Scandy high slightly more NW 

Edited January 30, 2017 by Ali1977

[Allseasons-Si]

7 minutes ago, booferking said:

This run more in line with ECM in the latter.

Yes a good match there BK

a torpedo has just smashed the mothership into smitherines,that's bigger than what a pistol will do

Edited January 30, 2017 by Allseasons-si

[SMU]

T228 & the SE starts to get that cold surface air feedlong back in...

[Daniel*]

It's coming...

[Nick F]

Good evening

18z GFS struggling to get a decent undercut to advect the deep cold over W Russia west out to T+240 - which is as far as worth looking for surface. Looks like a long drawn out stalemate over UK between Atlantic trough and block to east

EC weekly change of tact again, losing the low height anomaly to our west by week 3, strong height anomaly over Svalbard week 2 and generally +ve heights to our NW/N/NE week 4 and low height anomaly over SW Europe. Seems to be smelling the weakening PV and MJO colder phases later in Feb?

We were lead up the garden path just before the New Year (though not all of us perhaps) by the models, for a time, into believing that a cold easterly would come off in early January. But this was against background signal that was less than favourable for this outcome, namely muted MJO / -AAM / strengthening sPV

But looking ahead, we have probably the best chance that we’ve had all winter, given more encouraging background signals, these are:

-  The sPV shows signs of weakening as we have signs of wave 2 activity increasing in early February (via Scandi/Svalbard ridge) as well as the wave 1 attack that is displacing the PV.

-  The GFS this morning has shown the first proper split of the PV this season too.

-  The combination of the weakened PV via increase wave2 as we head through early February    and the models recently trending the MJO propagation more amplified into phase 8 around the second week of February, which with weakened PV, will IMO increase the likelihood of a –NAO as well as –AO.

But we may not see the transition to a colder pattern until 2nd week of February at earliest and more likely mid-month given the lag of the wave2 effects on the strat and MJO propagation. Both GEFS and EPS take MJO coherently through 5/6/7/8 which is better signal than all winter and suggests less interference with the propagation this time.

Before this potential, Atlantic still in control, and ramping up a gear later this week – worth keeping an eye on the low arriving across the south Friday evening into early Saturday shown on both 18z GFS and 12z EC, doesn’t look to pose too much of a problem wind-wise other than gales through E Channel, but may be deeper if it phases better with shortwave trough and left exit of jet streak. Some heavy rain too.

Another deepening low follows on its heels, though for now heads into France Sunday. A potentially stormy period into the weekend though.

EDIT - the 18z GFS gets there in the end with the undercut - FI, but as it keeps churning this promising evolution out, we can call it a TREND

Edited January 30, 2017 by Nick F

[The Weather Dragon]

There is a danger of previously mentioned loco zonal conditions persisting if we don't get an undercut - not good !

[The Weather Dragon]

13 minutes ago, Daniel* said:

It's coming...

nowhere near !

[Nick F]

2 minutes ago, The Weather Dragon said:

There is a danger of previously mentioned loco zonal conditions persisting if we don't get an undercut - not good !

Gets there in the end, that's 12z and 18z with undercut by mid Feb, yes I know FI, but a TREND if 00z carries on with it too

12z v 18z for day 15

[chionomaniac]

4 minutes ago, Nick F said:

Gets there in the end, that's 12z and 18z with undercut by mid Feb, yes I know FI, but a TREND if 00z carries on with it too

12z v 18z for day 15

Yes, it certainly wouldn't take too many tweaks from what is modelled here to achieve another 1991. I'll take the trend- displaced weakened vortex with a split in a favourable position to allow a westward moving Scandi block. The zonality we see this week and into next is inevitable because of the vortex displacement, but it could be a small price to pay for the long term rewards. All positive today for me, we don't need to see -10°C 850's rushing in from the east just yet....

[Man With Beard]

Wont repost ECM monthlies as Nick has already done so, but just thought I'd mention how quickly it ditched its idea from last week to keep the Atlantic in the ascendency. Dreadful winter for the ECM monthly goes on, particularly past D15. Anyone differing risks me posting a ton of charts in reply proving it!

Also interesting how the 850hpa temp anomalies stay above average despite the Scandi High anomalies. D11-D15 could well see a return to the surface cold, then, rather than deep cold - but with a sinking jet, hopefully, and therefore snow becoming more possible.

[Duane S.]

The trend to an undercut scenario remains favourable, true it doesn't look like taking place any time soon and we may well have to endure a tedious stalemate situation. With a growing block to our east and a longwave trough to our west, effectively cancelling each other out, whilst we sit in the middle, tearing our hair out watching the cold plummet down towards Turkey and Greece! All part of the likely process in getting the cold air to us in the first place, that Greenland arm isn't going to relent overnight.

Yep it would have been better a few weeks back but there are reasons, seasonal ones, why/how this setup is occurring now and not at the tail end of December. So I think that whilst there is a case to say that we have indeed been unlucky not to have had a proper cold spell so far this winter, maybe in hindsight (that wonderful thing) many (including me) probably did let our hearts rules our heads on occasions when the background signals were clearly saying "no, it's not for you UK, not yet". Moving onwards and into Feb, the effect of the ongoing Strat warmings, the eastward movement of the MJO, a more troubled vortex, increased wave 2 activity is for sure going to give us another shot at the big time.

Much water yet to pass under many bridges. A firm undercut trend is without a doubt emerging. I'm not in the least bit concerned at this stage about charts showing us just missing out (we'd better get used to it, I suspect there will be plenty more to come). Often, in these situations, the pattern does back west.

For me, the very fact we have a half decent chance like this is plenty good enough to draw me back into the chase. I'm expecting a stonking ECM to show up in the next day or 2!

Edited January 30, 2017 by s4lancia

[snowray]

Just a couple of words from me for newcomers in particular, I like to keep things relatively simple so here are three charts that continue the theme from my last post. GFS 12z you can see LP over Northern Italy and a nice clean undercut there producing an easterly and almost perfect set up as we start to pull in the deep cold from our east (On the ensemble suite 12z was a big cold outlier though of course). GFS 18z on the other hand there is no Low centred over Italy and since there is nothing to prop up the High it sinks, story of this winter, the air that comes up to the UK from the continent is cold and dry but has been modified on its travels further south so not as cold, its the difference between snow and cold rain. This is just one run and it will be no doubt all change again tomorrow.