Model Output Discussion 01/09/17

[nick sussex]

Looks like the models are determined to wring as much drama out of the current set up and its now a race between Atlantic energy and how quickly the low over the UK sinks se .

 

The quicker the low sinks se the greater chance of developing a colder set up because shortwave energy upstream is likely to try and cut towards the UK and phase with that low. You don't want early phasing because that could help blow up the low aswell as trapping the UK on the milder side so phase timing is crucial.

The Arctic high in tandem with increasing heights towards Greenland here plays an important role in forcing the low se. The UKMO which went rogue for a few runs seems to be backtracking towards the GFS/ECM solutions.

 

 

Edited November 11, 2017 by nick sussex

[cyclonic happiness]

funny how only some off topic posts get removed, it's almost as if there is a clique?

[SMU]

Evening All

So the nerves settle a little as the GFS & UKMO find a nice meeting point-

The last 12-24 hours have seen subtle changes from the GFS & the UKMO where  they have arrived at a general middle ground meeting point- The GFS has been more subtle with gradually amplifying the Scandi ridge & bringing the trough further & futher west but at all points it has the trough clearing the east of the UK all be it that clearence point has been edging back towards the east coast -

The UKMO has gone in reverse - it over amplified the original high pressure so much so it negatively tilted the trough - but particularly on the 12z its made it more positive - but it still DOESNT clear the SE at day 6 -

Its also worth noting that with my post the other day there was always going to be a fine line between an initial southerl flow which is what I expected- The UKMO still has a southerly at day 6

So not totally out of the clear with that trough clearing through however ever so slowly its becoming clearer in the models & cold weather is unusually still the form horse....

Eyes down for the ECM

S

Edited November 11, 2017 by Steve Murr

[northwestsnow]

Lets hope for upgrades in the coming days- ukmo is not as good as gfs at 144 but it seems to have got its wires crossed over recent days so heres hoping it follows gfs tomorrow.

EC will be fascinating again- fabulous and intriguing model output at the moment.

[Day 10]

3 minutes ago, nick sussex said:

Looks like the models are determined to wring as much drama out of the current set up and its now a race between Atlantic energy and how quickly the low over the UK sinks se .

 

The quicker the low sinks se the greater chance of developing a colder set up because shortwave energy upstream is likely to try and cut towards the UK and phase with that low. You don't want early phasing because that help blow up the low aswell as trapping the UK on the milder side so phase timing is crucial.

The Arctic high in tandem with increasing heights towards Greenland here plays an important role in forcing the low se. The UKMO which went rogue for a few runs seems to be backtracking towards the GFS/ECM solutions.

 

 

Crayons at the ready then Nick for the updated ECM. The good old day 10 charts do appear to be moving closer for once, let's hope you aren't putting a big red line through them!

[Frosty.]

The ukmo 12z is  being dragged kicking and screaming towards the other main models and it will have to catch up if Exeter continue on their current course. It's looking like a good time to be a coldie during the second half of November and hopefully well into december!!???..hopefully the Ecm 12z will keep up the good work from this morning☺ make it so..I mean snow?

Edited November 11, 2017 by Frosty.

[Methuselah]

36 minutes ago, knocker said:

Pictures speak louder than words

If only we could get that set-up in late December onward, It'd be an absolute blinder...Sad to say it but, as things stand, just now, the warmer-than-average SSTs in the North Sea might well confine any snow to high ground...?

My guess would be for maxes of between, say, 4-8C...Not to worry, it'll never verify anyway!

[knocker]

A quick glance at the GEFS 10-15 anomaly continues the general theme from last evening and this morning. The Canadian vortex lobe weakening drifting over the pole replacing the high pressure which encourages increasing positive anomalies over NE Canada and a general pattern shift east in the Atlantic and north west Europe. Thus retaining the NW upper flow over the UK and continuing unsettled with temps below average.

[knocker]

4 minutes ago, Ed Stone said:

If only we could get that set-up in late December onward, It'd be an absolute blinder...Sad to say it but, as things stand, just now, the warmer-than-average SSTs in the North Sea might well confine any snow to high ground...?

My guess would be for maxes of between, say, 4-8C...Not to worry, it'll never verify anyway!

Actually I was merely attempting to illustrate the difference between the two runs and therefore and one should be wary of reading too much into the detail for next weekend. Silly of me .

[Methuselah]

5 minutes ago, knocker said:

Actually I was merely attempting to illustrate the difference between the two runs and therefore and one should be wary of reading too much into the detail for next weekend. Silly of me .

No, it was my fault. With posts flying in at the rate of knots, I got the wrong end of the stick!

[Sperrin]

Great runs coming out these past few days and, as always, it's great to have such knowledgeable posters to analyse them. 

The GFS 12z ens for my location in NW Ireland (although i'm 100+ m higher than the nearest town) highlights the increased chance of seeing some of the white stuff. Hopefully the upgrades keep on coming!

[Iceaxecrampon]

12z - Mid November silliness at +228 - yes a cold trend developing but come on?

Surely not.

Cue forum meltdown.

[I remember Atlantic 252]

22 minutes ago, Iceaxecrampon said:

12z - Mid November silliness at +228 - yes a cold trend developing but come on?

Surely not.

Cue forum meltdown.

Looks a bit like 21 years ago, legendary 2 days earlier

[Mucka]

Rather progressive ECM this evening, thought it would be closer to GFS personally.

It is quite consistent with previous runs other than that, though I wonder if it will be well represented within its ensembles from around day 7?

Edited November 11, 2017 by Mucka

[Ross Andrew Hemphill]

4 hours ago, damianslaw said:

Just focusing on the near time - there could be a surprise fairly low level albeit shortlived snowfall event on Monday in central parts of Scotland at least - as we see a frontal feature moving into cold level air.. with the aid of evaporative cooling, I won't be surprised if a few places with modest height - say about 250-300m sees a bit of a wet cover during Monday, before the snow turns quickly to rain. Nothing unusual, but will be interesting to see. Chances will increase if the front slows down, and there are signs it may be about to do this.

Into next week proper, it looks mostly changeable, trending cold again in the second half as polar/arctic maritime air once again embeds itself, which could mean it is the fourth weekend in a row with a northerly feed.

Longer term - as I said the other day, expect a few more twists and turns in the models, before they settle down on a consistent theme early next week. 

This is what I thought when I saw the 850s for Monday when that front moves in, let's hope so! 

[karyo]

The ECM has a complete luck of cold upper air despite following the same pattern as the GFS. 

[The PIT]

Interesting about face by UKMO so a basic agreement at t144 with slight variations on the theme but what has to expected at T144.

[bluearmy]

When the ecm is struggling to amplify then you begin to wonder if things can swing back ........

[Tim Bland]

51 minutes ago, Iceaxecrampon said:

12z - Mid November silliness at +228 - yes a cold trend developing but come on?

Surely not.

Cue forum meltdown.

Whilst the Synoptics look good the conditions on the ground are nothing special. Unless you live above 400m you will not see anything wintry from the ECM. We need to see lower temps modelled but I’m struggling to see how this could be achieved or where they will come from. As we haven’t had the PV bottling up the cold yet there is nothing to release ?

[Frosty.]

Watching these individual op runs churning out is an emotional rollercoaster but I'm keeping faith with Exeter regarding the bigger picture..I believe we will get an early taste of winter in the next few weeks!?

[Singularity]

https://www.theweatheroutlook.com/twodata/chart.aspx?chart=///www.theweatheroutlook.com/charts/gem/192_mslp500_arc.png?cb=755

GEM takes GFS and ups the ante.

Too many deep troughs in the mix to get a clear angle on things; slight day 5-6 variations in timing and path have very large impacts by day 8+. As in - larger than usual.

[blizzard81]

10 minutes ago, bluearmy said:

When the ecm is struggling to amplify then you begin to wonder if things can swing back ........

The main theme I see from that ecm run is the ever decreasing heights over central and southern Europe. Always good to see as we approach December. 

[Methuselah]

I am getting rather worried, chaps; I'm off to babysit my grandchildren and I am afraid that, when I return, there'll be no toys left for me to play with!

[Polar Maritime]

Can we please use the model banter thread for general chit/chat, Ta.

[bluearmy]

9 minutes ago, blizzard81 said:

The main theme I see from that ecm run is the ever decreasing heights over central and southern Europe. Always good to see as we approach December. 

But that Atlantic profile won't allow for any reinforcements which means it will just fill in situ. Result is slowly sinking MLB as the jet runs across the top - only positive I take from that ecm op by day 10 is the continued absence of Canadian vortex.