Model output discussions pm 31/12/15

[mountain shadow]

GFS 12z showing the more likely pattern, with a failure of the Easterly. It is now I believe picking up the MJO phase 7/8 signal with the cut off Greenland high, where we can look North for the cold not East.

I believe the extended runs have been picking up on this for a while. 

This could give a more widespread colder spell to favoured areas ahead of any SSW occurring in February.

[Day 10]

Purely for fun but nice end to the run. Off to get drunk now Happy New Year to all, ENJOY!!!

[IDO]

26 minutes ago, mountain shadow said:

GFS 12z showing the more likely pattern, with a failure of the Easterly. It is now I believe picking up the MJO phase 7/8 signal with the cut off Greenland high, where we can look North for the cold not East.

I believe the extended runs have been picking up on this for a while. 

This could give a more widespread colder spell to favoured areas ahead of any SSW occurring in February.

You still think we will get an SSW in Feb? No signs out till D16 yet and take 30 days on from there and we are mid Feb. I remember last year when an SSW was suggested and delay after delay and we didn't get one in the end. 

I think we need to look for trop led changes for the next month at least and there is a signal for possible heights building end Jan in Greenland so although the GFS seems a bit presumptuous,  we would take it:

   

Early days yet on that. The GFS op run is more seasonal with respect to uppers so no repeat of a CET of +5c in Jan. Support from the GEFS for a brief incursion of lower uppers into the NE around D5-6:

Then into a cool westerly flow.

 

Edited December 31, 2015 by IDO

[Allseasons-Si]

Well! well! well!

gfs control going the same way as ukmo/navgem did on there past runs

navgem coming out now,off now for the festive bash

HAPPY NEW YEAR TO EVERYONE

 

 

[Captain Shortwave]

The control run gets the cold air a little further south and west compared to the operational.

A real hodge-podge of solutions even at day 6, some good ones in there.

I think this would be Mr Murr's landing point (Warning cherry-picked ensemble member)

-8C isotherm across the whole of the UK with snow showers for eastern areas.

Edited December 31, 2015 by Captain Shortwave

[Liam J]

GFS, UKMO & GEM @ T144,  reasonably similar with the trough placement over the Atlantic, GEM would keep any milder air south of the UK. 

[nick sussex]

Well you couldn't make it up! The GFS 12hrs run heads towards the UKMO 00hrs run and the UKMO 12hrs heads in the other direction.

The issue is the half baked scenario where the models can't decide whether to clear the low se'wards or keep the elongated shortwave energy running nw/se.

Still the ECM to come and wouldn't be surprising to see that come out with a different solution.

[SMU]

17 minutes ago, nick sussex said:

Well you couldn't make it up! The GFS 12hrs run heads towards the UKMO 00hrs run and the UKMO 12hrs heads in the other direction.

The issue is the half baked scenario where the models can't decide whether to clear the low se'wards or keep the elongated shortwave energy running nw/se.

Still the ECM to come and wouldn't be surprising to see that come out with a different solution.

I bet my xmas prezzies the ECM is much different tonight

again the updated 12z JMA to 84 has the ridge & the arpege to 114 does as well

eyes down for NAVGEM & ECM

[Mair Snaw]

6 minutes ago, nick sussex said:

Well you couldn't make it up! The GFS 12hrs run heads towards the UKMO 00hrs run and the UKMO 12hrs heads in the other direction.

The issue is the half baked scenario where the models can't decide whether to clear the low se'wards or keep the elongated shortwave energy running nw/se.

Still the ECM to come and wouldn't be surprising to see that come out with a different solution.

Its like i said earlier.... Jan 2013 one model going one way the rest the other... then as soon as the rest join the party the first model drops it and goes another way then they all go back again with none of them being correct until about t48....

[Liam J]

NAVGEM coming out sporadicly.

6z 144hrs  12z 150hrs 

[damianslaw]

Reliable timeframe is very short at present - about 96 hours tops. It will probably take another day until they agree on the movement and position of the low pressure early next week - with this in mind, expect more conflicting signals in the next few model runs. Might be best taking a break from model watching until things become much clearer come Saturday - have the new year off!.

[nick sussex]

8 minutes ago, THE CHOSEN ONE said:

I bet my xmas prezzies the ECM is much different tonight

again the updated 12z JMA to 84 has the ridge & the arpege to 114 does as well

eyes down for NAVGEM & ECM

It wouldn't surprise me, in the space of 12hrs the shortwave which was expected to deepen and run east close to me here has disappeared, which I'm very relieved about ! So it doesn't really give much confidence to what the outputs are doing from within the normally " very reliable timeframe"!

Edited December 31, 2015 by nick sussex

[BlueHedgehog074]

Essentially, the models do show that there is going to be a big wrestling match between the Scandinavian/Russian High Pressure systems and the Atlantic Trough. The High Pressure developing to our North-East has decided it has had enough of the Atlantic Low Pressure systems and that evil Greenland Vortex causing carnage in the UK delivering problematic floods to places. And so, the Scandinavian/Russian block is going to punish the Atlantic Lows by squashing them to death and force them to track South-East into Europe. 

There is also currently a lot of warm air getting pumped Northwards towards the Arctic area (Warm Air Advection) as shown from the example in the 06Z GFS below.

The arrows showing the warm air getting drawn vertically Northwards towards the Arctic thanks to pronounced amplification of high heights extending from mainland Europe towards Northern Russia. Some of this will help to choke the Vortex around Greenland area and weaken it.

...and in some ways will allow some of the ridging from the blocking to our North-East to back further West to our North towards Greenland or Iceland (see next chart below).

The below example from the 00Z ECMWF, using the European view of the model, shows the sort of pattern that could result towards next week. 

Some areas of High Latitude Blocking, with the strongest areas of heights towards the Russia area, putting a spell on the Atlantic Lows and set up possibilities of these disrupting against the North-Eastern UK blocking. While there is some variations of the exact track the Lows from the West will take and how far North or South they could edge themselves through the UK, I think the general pattern is to see a stream of Lows filter in from the West/North-West and extend themselves South-Eastwards into mainland Europe across the UK at times. And as some of the people such as Phil, mentioned, some very cold 850hPa air out to our North-East could get pulled Westwards towards us at times. Though it does seem as though that Eastern/North-Eastern areas of the UK (for now) could see the best chances of some of this cold upper air. North-Eastern areas probably the most likely as well to see the best of any Easterly influences from the Russia/Scandinavian block. But all of this will depend on the exact positioning of the pressure/upper height patterns closer to the time itself.

Additionally, the chart above illustrates how the areas of Vortex to our North-West over Greenland becomes terminated for a while as some fairly modest heights settle above to our North disrupting some of the very low heights in that area. Sorry Greenland Vortex, your mission is aborted.  

Further on towards the end of next week, and it has seemed to be the case that the Atlantic Lows out West could become very frustrated with our block to our North-East - angrier Lows taking the spot light over and to the North-West of the UK. 

Examples from the GEM, GFS and ECMWF below:

And, below, the 12Z GFS's take for that period.

(The Atlantic Low a bit more deeper and rounder compared to the other examples above and generally positioned a little further West).

It's something I think Bluearmy talked about yesterday regarding a more Atlantic influence taking over eventually, with the blocking to our North-East getting stamped-out. It's been a trend on some models as well to see some of the Lows beyond the second half of next week to become accompanied by much lower 500mb heights with the risk of a more Vortex-y influence affecting the UK. (may sadly mean more wind and rain for parts that need no more). But its not infeasible that with enough disruption and undercutting to the Low (especially should heights to our North be underdone at that time-frame) that some frontal snowfall could occur upon approach of this possible deep Low out West. Particularly if the Low runs up against enough cold air over, or to the East of, the UK. Despite some uncertainties in the nearer time-frame (mostly the details really), how much this possible deeper Low behaves could further affect what sort of pattern occurs afterwards. Personally, feel as though that Low will probably just push through the UK/Northern UK or, if it gets really deep, perhaps just get stuck out to our North-West for a while. Would be ideal to see some of those deep Lows later next week losing their ball-shape so it could become more squashed and undercut/disrupt better. 

Won't go to much detail, but some operational models towards deep FI have shown possibilities for some heights to develop around Greenland, which may lead to further possibilities of some cooler or colder weather further down the line. Would kinda relate to the thoughts of those on here such as Glacier Point, who hint at some blocking possibilities to our North-West. But I suppose for those wanting to see a colder spell (in case the possibilities in these next few days or so don't deliver, more so if you're towards the South of the UK), then let's hope any ideas of the North Atlantic Oscillation going negative later on into January doesn't become something that's too Western based. Could mean the coldest air ends up digging South a bit too far West/North-West in the Atlantic with the cold weather fans in the UK being on the wrong side of it (unless perhaps you're over Northern UK). Too far out, however, to worry about at the moment. 

While it does look as though unsettled conditions could continue, there is always the chance of some drier spells between the likely West/North-West to South-East tracking Lows next week. For those fed up with the flooding issues, it might be the best that could be achieved for now, otherwise it's just hoping somehow there could be more influence from ridging either from the block to our North-East or the Azores High to our South-West. Seems, however, unlikely for the time being.

Nevertheless, there is still some doubts regarding the developments for next week. A block to our North East looks likely: 

and a chance for Lows to undercut that block from our West with a Southerly tracking Jet Stream. Looks as though that while it's uncertain as to how cold next week may get, it should at least be cooler than it has been recently (except for today where the UK is now under a cool Westerly flow). The chance of colder weather increasing the further North-East in the UK you are. But.. can the Lows out West disrupt enough and reach Europe without filling out too quickly? Can they be pushed far enough South to the South of the UK and bring more areas a chilly Easterly feed? And will this mean wintrier possibilities further South? And even if not, can enough devastation to the Vortex be maintained to bring a bigger smile to the cold fans' faces towards mid-January? And will a UK High Pressure system come to the rescue for flooded areas at some point?

Some question to be answered. But hopefully if this wet weather has tested your patience too much, that the rain train service will eventually come off the track. 

Also like to wish all of you a Happy New Year and may the weather bring lots of surprises for us all to look forward to - especially of the whiter and/or drier kind. 

[Shuga ice]

I wish people would understand that charts beyond 96 are complete guess work, a 5 year old with crayons could scribble more accurate charts.  It is pointless hanging on every output. 

Todays charts are showing anything from cold with a chance of snow to wet and windy.  I look at the charts once every three days.

[mulzy]

4 minutes ago, Shuga ice said:

I wish people would understand that charts beyond 96 are complete guess work, a 5 year old with crayons could scribble more accurate charts.  It is pointless hanging on every output. 

Todays charts are showing anything from cold with a chance of snow to wet and windy.  I look at the charts once every three days.

Simply not true!  Evidence please?

Edited December 31, 2015 by mulzy

[Johnp]

2 minutes ago, Shuga ice said:

I wish people would understand that charts beyond 96 are complete guess work, a 5 year old with crayons could scribble more accurate charts.  It is pointless hanging on every output. 

Todays charts are showing anything from cold with a chance of snow to wet and windy.  I look at the charts once every three days.

Good for you, see you on the 3rd.

[Polar Maritime]

Can we now have sensible discussion around the models please, Thanks.

Happy New Year.

[shaky]

Nothing yet on the ecm steve?!looks similar to gfs at 48 hours!!

[Bullseye]

Wxmidwest on Twitter back in October did a graph showing North Pac SLP for October and showed what this could signal based on past results and the graph should the DJFM NAO running in negative territory and today he uploaded this which to me looks good:

 https://twitter.com/wxmidwest/status/681736611143417856

Edited December 31, 2015 by Bullseye

[johnholmes]

1 minute ago, Tim Brawn said:

That would be great , shame is whilst they differ so much its no wonder people get their knickers in a twist .     Rain bouncing down here again , not forecast and 5C

but where please? 

Can you pop your nearest town in so we all know what the weather is in your locality, it really helps the enjoyment for us all.

Again welcome to Net Wx.

Edited December 31, 2015 by johnholmes

[phil nw.]

3 minutes ago, shaky said:

Nothing yet on the ecm steve?!looks similar to gfs at 48 hours!!

Maybe best wait until the run has progressed a bit shaky and then give a bit more detail.Perhaps a chart or 2 or even a link.?

Ta.

[radiohead]

ECM looks quite similar the the UKMO at T96

 

[chris55]

1 hour ago, Allseasons-si said:

Well! well! well!

gfs control going the same way as ukmo/navgem did on there past runs

navgem coming out now,off now for the festive bash

HAPPY NEW YEAR TO EVERYONE

 

 

GFS control would deliver plenty of snow for most!!!

[gottolovethisweather]

Snow or rain, dry and chilly or moist and mild, come hell and high water (no pun intended) whatever the weather look after yourselves and have a wonderful evening my friends.

See you in 2016 and I for one am looking forward to a most intriguing final two-thirds to Winter. 

[Liam J]

Those strong heights over Scandi just get obliterated from T48 onwards.

48 hrs  120hrs 

UKMO, ECM & GFS  @ 144hrs