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Matty H
Sunday, November 10, 2013 9:48:39 PM

Has anyone noticed the unusually large scatter on the GEFS? I don't think I have seen anything quite so large in a while. And indeed the scatter for the 850s is actually greater on the 17th than on the 20th. The real divergence starts only 4 days after intilisation.

Originally Posted by: Quantum 


Looks pretty bog-standard to me? 😕
Quantum
Sunday, November 10, 2013 10:05:33 PM

Has anyone noticed the unusually large scatter on the GEFS? I don't think I have seen anything quite so large in a while. And indeed the scatter for the 850s is actually greater on the 17th than on the 20th. The real divergence starts only 4 days after intilisation.

Originally Posted by: Matty H 

Looks pretty bog-standard to me? 😕

Originally Posted by: Quantum 


 


I have a few ensemble snapshots on my computer still, there does seem to be more scatter. Idk it just seems the divergence starts a little earlier than usual. Perhaps 5 day forecats would have reduced accuracy.  


Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
2023/2024 Snow days (approx 850hpa temp):
29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)

Total: 8 days with snow/sleet falling.

2022/2023 Snow days (approx 850hpa temp):

18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)

Total: 7 days with snow/sleet falling.

2021/2022 Snow days (approx 850hpa temp):

26/11 (-5), 27/11 (-7), 28/11 (-6), 02/12 (-6), 06/01 (-5), 07/01 (-6), 06/02 (-5), 19/02 (-5), 24/02 (-7), 30/03 (-7), 31/03 (-8), 01/04 (-8)
Total: 12 days with snow/sleet falling.
squish
Monday, November 11, 2013 8:12:17 AM
Amazingly quiet on here given the range on interesting charts being thrown out by the models

http://modeles.meteociel.fr/modeles/navgem/runs/2013111100/navgemnh-0-174.png?11-06 
http://modeles.meteociel.fr/modeles/gem/runs/2013111100/gemnh-0-180.png?00 

NAVGEM and GEM are now both going for much more continental blocking, with a trough( and quite a bit of cold air) stagnating over the UK ...



D.E.W on Dartmoor. 300m asl
Quantum
Monday, November 11, 2013 8:39:25 AM
http://modeles.meteociel.fr/modeles/gem/runs/2013111100/gemnh-0-180.png?00  NAVGEM and GEM are now both going for much more continental blocking, with a trough( and quite a bit of cold air) stagnating over the UK ...


 


I suppose its the fact that the charts are signalling really inperfect blocking. The anticyclone in the atlantic is really struggling to establish itself as a dominant feature over the atlantic or retrogress to greenland, so currently we are looking at a transient cold spell rather than anything more inspiring. That said, the pattern is certaintly promising. 


Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
2023/2024 Snow days (approx 850hpa temp):
29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)

Total: 8 days with snow/sleet falling.

2022/2023 Snow days (approx 850hpa temp):

18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)

Total: 7 days with snow/sleet falling.

2021/2022 Snow days (approx 850hpa temp):

26/11 (-5), 27/11 (-7), 28/11 (-6), 02/12 (-6), 06/01 (-5), 07/01 (-6), 06/02 (-5), 19/02 (-5), 24/02 (-7), 30/03 (-7), 31/03 (-8), 01/04 (-8)
Total: 12 days with snow/sleet falling.
GIBBY
Monday, November 11, 2013 8:46:44 AM

Good morning folks. Here is my account of the midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Monday November 11th 2013.


All models show a West to SW flow over the UK with a warm and cold front crossing East and SE as I type with a period of rain and drizzle clearing slowly from the NW to sunshine and scattered showers. Tonight a wave s shown to run East across Southern Britain with an enhancement to the rain for a time. Tomorrow and Wednesday will become dry and bright for many apart from the odd shower across the North as winds swing more towards the NW. A ridge crosses on Wednesday ahead of a new front passing quickly SE over Britain with another spell of rain followed by colder and fresher weather through Thursday with some sunshine. Pressure is shown to build quickly behind this and though Friday and Saturday will be technically dry and relatively fair days with plenty of cloud areas of fog and frost could form under the light winds should skies break overnight.


GFS then ends next weekend with a frontal band sinking South under High pressure with some rain and very murky conditions across Southern areas with the brightest conditions further North. Next week then shows pressure falling steadily over the UK with Low pressure deepening as it sinks South to a position South of the UK by midweek. This sets up a cold and strong Easterly flow across the South with rain or sleet at times in dull conditions. Further North High pressure will build strongly and this will extend South slowly to all areas by the end of the run with light winds allowing widespread frost and fog to form at night and failing to lift for many through the day making it very cold.


UKMO on Sunday shows slack winds and grey and misty conditions most likely across the UK. Pressure will be falling and a weakening trough caught up in the slack flow will deliver some rain at times across the South despite High pressure over the top.


GEM this morning indicates rather cold and unsettled weather developing next week as pressure falls after the weekend with Low pressure close by delivering rain at times for all in cyclonic and fresh winds. High pressure builds strongly over Greenland late in the run which could have implications on the UK after the term of the run.


NAVGEM too shows pressure falling over the UK from next Sunday at the same time as it builds north through the Atlantic towards Greenland. The weather would become unsettled and rather chilly with rain at times once we move into the new week.


ECM shows a trough sinking South over England next Sunday followed by falling pressure as Low pressure migrates South over the UK  early next week. As it deepens a temporary but cold NE flow looks likely with some rain and sleet possible on this Low's northern flank. Drier brighter weather over Scotland early next week would then extend South. It then looks like a return to changeable and milder air would be knocking on the door of the UK soon after the end of the run.


The GFS Ensembles show a very mixed bag this morning though the overall trend does appear to be a downward trend in temperatures. As usual there is a lot of scatter between members later in the run and the operational was a mild outlier in the North late on. Rainfall events would be frequent but not particularly noteworthy.


The Jet Stream shows the flow over Scotland currently, moving further North after this week before it buckles back across SE Britain at the weekend which possibly sets up a new flow running WNW to ESE across the UK or further South at least for a time early next week.


In Summary today the models seem to have picked up on a new trend this morning for about a week's time. The build of High pressure across the UK at the weekend is quickly dissolved as Low pressure near the Meditteranean provides a catalyst for Low pressure to the North to move down to join or absorb it. This brings a quick change to wet weather for a time early next week especially in the South and with cold air entrained on a NE flow it would feel very raw with some snow possible on the highest ground. The pattern thereon become less clear with ECM wanting to bring milder Atlantic air quite quickly back in with a reset of the Azores high. GFS,GEM and NAVGEM are less supportive of this, instead building pressure strongly to the West, NW or over the UK with more sustained cold pressure with widespread and persistent fog and frost problems likely should GFS evolve. In the interim period before all this happens we have a week of rather changeable and benign weather with occasional rain alternating with drier, rather chillier and brighter interludes.


Martin G
Kilmersdon Radstock Bath Somerset



Look up my New Facebook Weather Page  for all the latest up to the minute weather stories as they happen
Osprey
Monday, November 11, 2013 10:38:33 AM

Thank you Martin I need a dry day or two, to do some re-pointing this week


Nobody likes a smartass, especially another smartass...
If it ain't broke, don't fix it!
ARTzeman
Monday, November 11, 2013 12:06:58 PM

Thanks Martin.


Dry period after Tuseday morning will be nice.






Some people walk in the rain.
Others just get wet.
I Just Blow my horn or trumpet
Gusty
Monday, November 11, 2013 12:49:22 PM

Looking very likely to turn cold and potentially a little wintry for many.


http://www.theweatheroutlook.com/charts/gefs/gefsens850London0.png


Steve - Folkestone, Kent
Current conditions from my Davis Vantage Vue
https://www.wunderground.com/dashboard/pws/IFOLKE11 
Join Kent Weather on Facebook.
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Gooner
Monday, November 11, 2013 2:31:32 PM


Looking very likely to turn cold and potentially a little wintry for many.


http://www.theweatheroutlook.com/charts/gefs/gefsens850London0.png


Originally Posted by: Gusty 


Bit of a downward trend after 17th for sure


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


stophe
Monday, November 11, 2013 3:13:31 PM
Looks like this mornings ecm went off on one with the rainfall forecast.
http://www.weathercast.co.uk/meteo/eps/ensemble-rrrcum-london.gif 
Polar Low
Monday, November 11, 2013 3:30:14 PM

I like no 18 Steve very wintry later on -10 in a rush.



Looking very likely to turn cold and potentially a little wintry for many.


http://www.theweatheroutlook.com/charts/gefs/gefsens850London0.png


Originally Posted by: Gusty 

doctormog
Monday, November 11, 2013 4:30:35 PM

I like no 18 Steve very wintry later on -10 in a rush.


Looking very likely to turn cold and potentially a little wintry for many. UserPostedImage
http://www.theweatheroutlook.com/charts/gefs/gefsens850London0.png 

Originally Posted by: Polar Low 

Originally Posted by: Gusty 



The -10°C t850 isotherm actually reached the Scottish mainland on the 06z op run (albeit at +204hrs!)

It may just about get there at a similar time point on the GFS 12z op run which is not massively different to the 06z at the time of writing (out to +174hrs)

http://www.wetterzentrale.de/pics/Rtavn2042.png 

http://www.wetterzentrale.de/pics/Rtavn2162.png 
Ally Pally Snowman
Monday, November 11, 2013 4:42:12 PM
Charmhills
Monday, November 11, 2013 5:01:11 PM

Our first cold shot of the season would be nice should it verify.


Loughborough, EM.

Knowledge is power, ignorance is weakness.

Duane.
Polar Low
Monday, November 11, 2013 5:10:07 PM

Nice shape lovely spilt might be some beefy showers in those warm sst


http://www.meteociel.fr/modeles/geme_cartes.php?ech=216&code=0&mode=0&carte=1&archive=0


 


http://www.meteociel.fr/modeles/geme_cartes.php?&ech=222&mode=1&carte=1

LA2B MeridFlowEuro09
Monday, November 11, 2013 5:24:03 PM
Hello everyone, it's been nearly another month since I last posted on this Model Output Discussion.

It is interesting that GFS is sticking to UK possible return of NNW or NW and then NE flow of Arctic Low Pressre, come the period 18th November right through to the 23rd November that today's 12z GFS run is offering some colder arctic winds and some sleet and hill snow showers and mix of rain but also snow showers for Scotland N Ireland North England and bring them all to the South of UK.

At time of writing, I still have to see Sunday t144h UKMO chart 12z run, hopefully it will match GFS- by then still average to slightly above temps across all of auK on the Sunday.

So much Blocking a highs mid North Atlantic and Western Central Europe, Meditteranean SE France W Italy Low Pressure quite helpful, and the Deep Low Pressure over Svalbard and Norwegian Sea plus over Iceland and further Deep Low's moving north in far NW N Atlantic to West and SW Central Greenland by 19-22nd November, the Deep SE diving Low move SE from Iceland to North and NW UK SE wards from Iceland and propelled deep SE arctic Norwegian SEa Liw over Near Svalbard and NW of Norway.

Large WNW N Atlantic High 15th to 18th persist with blocking in place- I just hope that through this week the UKMO and GFS continue with the current week weather of West to ENE bendy areas of North Atlantic E SE Canada NE USA NW through N Atlantic Areas of Low's move through Iceland - bring heavy rain Wednesday 13th p.m.,and Thursday14th a.m. Heavy Rain then cold NW winds, then cold Thursday day and night for Central and East Britain this day 14th Nov. 2013.

High pressure build strongly Friday 15th over Central E Europe and UK W Europe with SE tracking alow through France on Thurs 14th and Fri 15th Nov, that then spins and moves SSE over South Central France to W Italy and Western Med., during that time and through to 17th Nov.

A Number of De Lows affecting Svalbard and West a North Norwegian/ SE Arctic Sea and other Deep Lows moving Through E Canada to SW Grrenland.

There is very cold Arctic pool of air over Greenland with some High pressure during later this week and early in 3rd week November, some Warm air advection with a Polar Vortex placed over West and SW Greenland via E Canada and Far NW Atlantic, similar Vortex of Svalbard and SE arctic Sea Low Pressure during 2nd and third week of this month is to bring the UK cold NW to SE sliding Low from to cross the UK during 19th to 22nd Nov. 2013.

I hope we get agreed UKMO 12z run with GFS model throughout this week.

We live hope in NW Europe, it may occur.
Climate is warming up, Scotland and N Ireland and North England still often gets some Winter frost, ice and snow, November to March, but the SE and South UK including S Central England and Wales, together with the West and North through the year, they sometimes get more rain than London and S SE England, where some longer dry fine spells without much heavy rain is seen every year.

The North Atlantic Sea often gets some much Colder Wintry conditions from November to March Months, and Mild SW and South winds tend to be more frequent over the East and SE of North Atlantic Sea, as the Azores High tends to stay in charge. 

With this warmth and heat, the Central and South UK has become mostly free of snow and frost.
White Meadows
Monday, November 11, 2013 5:28:43 PM
Definitely something of a pattern change showing up now for the past 3 days. The trough is well & truly 'dug in' over Northern Europe by +192
Some runs showing more height rises over Greenland than others… some showing more of a NE'ward displacement but something of a change is afoot.

ECM will be looked at with further interest this evening.
nickl
Monday, November 11, 2013 5:29:00 PM

today's gem 12z op gives us the chance to use one of my phrases from last thursday - 'if only it were january' !


 

Gooner
Monday, November 11, 2013 5:30:59 PM
Ally Pally Snowman
Monday, November 11, 2013 5:34:03 PM

Indeed the UKMO looks very good long term for a decent cold spell.


http://www.wetterzentrale.de/pics/Rukm1441.html


Bishop's Stortford 85m ASL.
Russwirral
Monday, November 11, 2013 5:42:50 PM

I must say - the end to that last run on the GFS had a whiff of Winter 2012/2013 about it.  With HP to the north east and South west and LP over central and southern Europe.


 


will be eyes peeled for any developments of that. :)  Wouldnt normally bring this kinda thing up, but seeing as that weather pattern only finally subsided 5 months ago leaves me with a slightly Roger moore raised Eyebrow o_O


 


 


http://cdn.nwstatic.co.uk/gfsimages/gfs.20131111/12/300/h850t850eu.png 


David M Porter
Monday, November 11, 2013 5:46:45 PM


Indeed the UKMO looks very good long term for a decent cold spell.


http://www.wetterzentrale.de/pics/Rukm1441.html


Originally Posted by: Ally Pally Snowman 


A decent dry spell would do me nicely right now, even if it wasn't especially cold. That would allow the ground to dry up at least a little after the heavy rainfall of recent weeks.


Lenzie, Glasgow

"Let us not take ourselves too seriously. None of us has a monopoly on wisdom, and we must always be ready to listen and respect other points of view."- Queen Elizabeth II 1926-2022
Polar Low
Monday, November 11, 2013 5:47:53 PM

navgm looks a bit less tricky with things in canda than gfs and the amount of A Wave that is required for the block not  to become to flat.      


Nice from navgm


 http://www.meteociel.fr/modeles/navgeme_cartes.php?ech=180&code=0&mode=0&carte=1&archive=0


 


cant explain like Darren or James but see here gfs at that sort of time ive played many times could get tricky


  http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=162&mode=0&carte=1

Russwirral
Monday, November 11, 2013 5:53:37 PM


navgm looks a bit less tricky with things in canda than gfs and the amount of A Wave that is required for the block not  to become to flat.      


Nice from navgm


 http://www.meteociel.fr/modeles/navgeme_cartes.php?ech=180&code=0&mode=0&carte=1&archive=0


 


Originally Posted by: Polar Low 


 


Nice to see some yellows head towards Greenland.


Polar Low
Monday, November 11, 2013 6:17:48 PM

like what i said earlier with risk of gfs


http://www.meteociel.fr/modeles/gefs_cartes.php?code=3&ech=150&mode=0&carte=1


 


 But some cold runs in the mix


http://www.jp2webdesign.co.uk/two/ensembles/

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