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Model output discussion - heading into 2018


Paul
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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

You can clearly see the big change which NOAA commented on by comparing these charts both to the 4th January 00hrs from the ECM.

So the one from the 26 December 00hrs to T216hrs:

ECH1-216.thumb.gif.3b3bc997c38cb3ddb927bec314dde7d9.gif

 

Then compare that with this mornings 00hrs to T168hrs:

ECH1-168.thumb.gif.26fcd1086168803cdbee3dfe0b829f26.gif

 

At this time given these changes ruling out some colder conditions from the ne would seem a bit premature. I think we need to see whether theres a further slowing and increase in amplitude upstream. So a few more runs needed.

 

 

 

Edited by nick sussex
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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .
12 minutes ago, bluearmy said:

 The gefs 12z have decent continuity with the previous run - jet angled nw/se into Europe with the uk probably under the mean trough - could easily be fairly wintry. in fact, given that we are looking at a strong zonal flow heading down through the strat by day 10, surprising how the AO and NAO manage to be negative in the 11/16 day period and there is plenty of northern blocking evident on the gefs members. maybe day 16 is too soon for the trop to respond to the increased flow higher up. That goes against the theory that we won't see any n blocking evident before day 16. 

The GEFS might show good continuity but that might mean continuously incorrect if they have failed to develop the ne USA coastal low .

If that verifies how many of the current GEFS get shredded ?

Thats a significant feature which means incorrect handling of that results in everything after being incorrect.

Of course the low isn’t within the more reliable timeframe so it’s a case of seeing what happens over the next few runs.

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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
21 minutes ago, knocker said:

Looks like there or thereabouts for mjo phase 2

5a452f2288cee_phase2.thumb.gif.7386ca14d1911d08580a3a24a6ce2143.gifgefs_z500a_5d_nh_61.thumb.png.3d8ebbd7db2f4e4f74aa7aaeecfc020e.png

Well its only my two penneth but i don't think that looks mild zonal at all?

I'd say PM would be on the menu! :)

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Posted
  • Location: Carryduff, County Down 420ft ASL
  • Location: Carryduff, County Down 420ft ASL
7 minutes ago, Paul_1978 said:

I thought the GFS 12z was pretty good - it’s hardly a raging Atlantic is it!

It's pretty unsettled but of the polar maritime variety. Cold rain for most, Northern mountains will do well though.

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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
5 minutes ago, mountain shadow said:

It's pretty unsettled but of the polar maritime variety. Cold rain for most, Northern mountains will do well though.

Hmmmm...i wouldnt say northern mountains only MS.

You could be correct of course..

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Posted
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
  • Location: Leeds/Bradford border, 185 metres above sea level, around 600 feet
8 hours ago, bluearmy said:

As @catcol pointed out yesterday, the SOI running heavily negative is nino rather than nina. Just as last year when we saw the neg QBO fail (unprecedented or very rare ??) we are now seeing things happening in the Pacific which we haven't before. Caveat being since we have been recording this stuff! 

Not sure why you think this is unprecedented. Plenty of Nino/Nina events don't see full ocean-atmosphere sync.

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Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

Coldish Pm air is what we have had the past few days, albeit with a brief Polar m burst. This is quite possible looking at the GFS output if the recent ones are anywhere near the mark.

There is good support from the 500 mb anomaly charts for a broad westerly pattern. This in turn does allow for, relatively brief, outbreaks of colder air.

What is not likely in the next 2 weeks or so is any prolonged deep cold air from any of the cold directions, brief yes, lengthy, say 5 days or more no.

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Posted
  • Location: Eastbourne and Larnaca,Cyprus .
  • Location: Eastbourne and Larnaca,Cyprus .

Pretty good agreement developing now between the outputs . An issue is the PV being pushed south at the time you want that not to happen.

Even with that both ECM and GFS try to develop some weak height rises to the ne and more amplitude upstream could still carve a more nw/se jet track towards the UK.

A battle ground scenario can’t be ruled out given the overall set up.

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Posted
  • Location: Camborne
  • Location: Camborne

The ecm has an intense little low that ‘bombs’ and tracks around the southern quadrant of the main low and moves  quickly north east to be over western Scotland 966mb by 0600 on Sunday so briefly some heavy rain and gales in that area.

From this point we have a dumbbell affect with the main low drifting SE to be north west of Ireland and another low that has formed in the southern circulation running quickly across Wales and southern England through Monday 

These quite quickly clear resulting in some very brief ridging but meanwhile another low has formed off the eastern seaboard around the base of the upper trough and by 1200 Tuesday has also undergone explosive cyclogenesis and is 960mb in mid Atlantic, with the associated front west of Ireland.

These sweep through overnight accompanied by heavy rain and westerly gales, perhaps severe in the north  and once cleared by 12 Wednesday the strong wind will veer north westerly.

These also move away very quickly (everything is moving at pace) and by 12 Thursday the nest deep low is west of Scotland with the UK in the associated warm sector, Thus more rain and strong winds.

In a nutshell very unsettled with some very strong winds and some quite large rainfall totals particularly in western Scotland but down all of west Britain.

ecm_mslp_uv850_natl_6.thumb.png.cf48e1a5c0b58d759068315f9eaae7e7.pngecm_mslp_uv850_natl_7.thumb.png.fceefff3fa89ffef7df500993734168a.pngecm_mslp_uv850_natl_8.thumb.png.113c3527ff7a78394be4a9eeadfa4c02.png

ecm_z500a_5d_nh_11.thumb.png.2f1e9229c1fa1d27370b3d765670b6d0.pngecm_t850a_5d_nh_11.thumb.png.d2e78718b7a5ed464a2da8a2ee02b0ac.png

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Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
1 hour ago, knocker said:

Looks like there or thereabouts for mjo phase 2

5a452f2288cee_phase2.thumb.gif.7386ca14d1911d08580a3a24a6ce2143.gifgefs_z500a_5d_nh_61.thumb.png.3d8ebbd7db2f4e4f74aa7aaeecfc020e.png

Yes - Atlantic in control for the foreseeable under +NAO conditions. No change to this until, or unless, we see the MJO progress further east... and even then, if Nina tightens it’s grip, there is no guarantee of modifying the +NAO profile. No sign at the moment of major vortex distress either.

Pleased for all those seeing snow from polar north westerlies in a mobile pattern. For such places a Nina winter can be a very good winter. 

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Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
38 minutes ago, summer blizzard said:

Not sure why you think this is unprecedented. Plenty of Nino/Nina events don't see full ocean-atmosphere sync.

True - but the global atmospheric state is well coupled to the Nina base state now, and the SOI is a region specific measurement of the strength of Nino/Nina. It is a little strange to see it sitting so consistently negative for so long... though I doubt it has any significance for global synoptics (unless someone can tell me different...)

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

As has been said before, it all looks rather like the 'zonal' spells of 50 years' back: very unsettled with temps oscillating, by maybe 3Cish either side of normal...So, plenty cold enough for snow to fall at times - even darn sarf - on occasions; Highland Scotland could be in for a bit of a pasting?:santa-emoji:

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Posted
  • Location: North West Leeds 124m
  • Location: North West Leeds 124m
3 minutes ago, Catacol said:

Yes - Atlantic in control for the foreseeable under +NAO conditions. No change to this until, or unless, we see the MJO progress further east... and even then, if Nina tightens it’s grip, there is no guarantee of modifying the +NAO profile. No sign at the moment of major vortex distress either.

Pleased for all those seeing snow from polar north westerlies in a mobile pattern. For such places a Nina winter can be a very good winter. 

I realise it's not great for lowland snow but I much prefer this set up to the one that dominated last winter when high pressure to our south wouldn't budge. If I recall correctly down south you had a fair amount of frosts but up here it was mostly grey mildish dross. I actually like this atlantic cool/cold zonality!

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9 hours ago, bluearmy said:

As @catcol pointed out yesterday, the SOI running heavily negative is nino rather than nina. Just as last year when we saw the neg QBO fail (unprecedented or very rare ??) we are now seeing things happening in the Pacific which we haven't before. Caveat being since we have been recording this stuff! 

Unusual but not unprecedented - May, June, August and September 1999 for example saw SOI 30-day averages at or below the current level during a full on Nina with ONI values at -1°C and below compared to the latest -0.7°C value. The Australian BOM predict this will be a short and weak La Nina and consider the SOI volatile at this time of year.

Edited by Interitus
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Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
11 minutes ago, Northern Sky said:

I realise it's not great for lowland snow but I much prefer this set up to the one that dominated last winter when high pressure to our south wouldn't budge. If I recall correctly down south you had a fair amount of frosts but up here it was mostly grey mildish dross. I actually like this atlantic cool/cold zonality!

Yep - agree - though it’s hard to remove all nimbyism from forecasting and comments. Hence, for as long as I stay in lowland Somerset, the holy grail is northern blocking because only then can we get an airmass sufficiently cold to bring snow. Very different up north - and it isn’t an exaggeration to say I am job hunting in Scotland with part of the reason to return to some colder winters rather than the soul destroying misery of rain and mild dross that dominates down here.

Ironically I was in Leeds last week - just when it all turned milder. Sod’s law... but food at the My Thai restaurant was sublime and  more than made up for missing any snow.

Model runs for your part of the world suggest more white stuff on the way. Enjoy!

Edited by Catacol
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Posted
  • Location: st albans
  • Location: st albans
3 minutes ago, Interitus said:

Unusual but not unprecedented - May, June, August and September 1999 for example saw SOI 30-day averages at or below the current level during a full on Nina with ONI values at 1°C and below compared to the latest 0.7°C value. The Australian BOM predict this will be a short and weak La Nina and consider the SOI volatile at this time of year.

Thanks - I knew you would find one! What about unprecedented after November begins ?  Pointed taken re the Aussie view - it's in their backyard! 

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Posted
  • Location: Penrith Cumbria
  • Weather Preferences: Cold, snowy winters and warm sunny summers
  • Location: Penrith Cumbria
6 minutes ago, Catacol said:

Yep - agree - though it’s hard to remove all nimbyism from forecasting and comments. Hence, for as long as I stay in lowland Somerset, the holy grail is northern blocking because only then can we get an airmass sufficiently cold to bring snow. Very different up north - and it isn’t not an exaggeration to say I am job hunting in Scotland with part of the reason to return to some colder winters rather than the soul destroying misery of rain and mild dross that dominates down here.

Ironically I was in Leeds last week - just when it all turned milder. Sod’s law... but food at the My Thai restaurant was sublime and  more than made up for missing any snow.

Model runs for your part of the world suggest more white stuff on the way. Enjoy!

You will see more snow in Scotland that's for sure but be ready for some bloody awful summers, totally different from your current location in Somerset!

Andy

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Posted
  • Location: Lincolnshire - 15m asl
  • Weather Preferences: Frost and snow. A quiet autumn day is also good.
  • Location: Lincolnshire - 15m asl
Just now, Penrith Snow said:

You will see more snow in Scotland that's for sure but be ready for some bloody awful summers, totally different from your current location in Somerset!

Andy

Hehe for sure... but I grew up there and it’s too damned hot for me down here in July/August. Plus the M5 is a horror show in the summer. I’d happily trot back north if the chance opened up.

Hmmm... I need a model comment. Here’s one: at 6 day’s range the Atlantic looks to be in control. I think we might be saying a fair bit of this over the next 10 days or more...

ECH1-144.GIF?28-0

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Posted
  • Location: NW London
  • Location: NW London
1 hour ago, Ed Stone said:

As has been said before, it all looks rather like the 'zonal' spells of 50 years' back: very unsettled with temps oscillating, by maybe 3Cish either side of normal...So, plenty cold enough for snow to fall at times - even darn sarf - on occasions; Highland Scotland could be in for a bit of a pasting?:santa-emoji:

When 

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