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Brian Gaze
10 January 2016 16:40:35

CMC has it turning milder towards the middle of the next week:



Brian Gaze
Berkhamsted
TWO Buzz - get the latest news and views 
"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
Jayni C
10 January 2016 16:42:44


but it's a reflection of the model uncertainty that Chris stops on Friday.


Originally Posted by: Bertwhistle 


given the current cross model inconsistencies, i'm surprised he has gone beyond tomorrow . . . .

Nordic Snowman
10 January 2016 16:43:58


 


If the GFS has this one right with regard to the weather on Friday - Sunday of next week then it will be an extraordinary performance, as it will have "faced off" UKMO, GEM  and to some extent ECM, amongst others.


If, however, it gets the weather wrong for next weekend, we can draw a different conclusion.


An adjustment 300 miles north of this GEM chart would be fun for many (way into FI, I accept)...



Originally Posted by: Whether Idle 


GFS been doing well and beating UKMO...


http://www.emc.ncep.noaa.gov/gmb/STATS/html/new_acz5.html


Bjorli, Norway

Website 
Gandalf The White
10 January 2016 16:44:41


Compared to the 0z the GFS12z seems to accelerate the end of the cold spell.


 


Originally Posted by: Brian Gaze 


We're still in the same position that we have been for quite a few runs now.


Essentially GFS still wants to spit some energy off the main LP that moves up to Arctic Canada from T+48.  An innocous shallow trough forms south of the tip of Greenland which cuts of any WAA from the next LP system and opens the door for energy to surge east.


UKMO just shows the trough dissipating which both keeps the residual upper ridge in place and allows for the next burst of WAA.


GEM shows the same trough, albeit slightly later, but again like UKMO doesn't develop it.


I guess the good news is that we're only 24-48 hours from having this resolved.


 


Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Whether Idle
10 January 2016 16:46:05


 


GFS been doing well and beating UKMO...


http://www.emc.ncep.noaa.gov/gmb/STATS/html/new_acz5.html


Originally Posted by: Nordic Snowman 


Indeed, thanks for the up to date verification stats.


Dover, 5m asl. Half a mile from the south coast.
David M Porter
10 January 2016 16:51:44


 


GFS been doing well and beating UKMO...


http://www.emc.ncep.noaa.gov/gmb/STATS/html/new_acz5.html


Originally Posted by: Nordic Snowman 


Maybe, but it has already changed it's tune in recent days in one respect. Remember the LP system it showed developing over the Azores late on in the coming week in a few runs a couple or so days ago which it then showed to move over ot close to southern England? That feature didn't last long.


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
Gandalf The White
10 January 2016 16:52:59


 


If the GFS has this one right with regard to the weather on Friday - Sunday of next week then it will be an extraordinary performance, as it will have "faced off" UKMO, GEM  and to some extent ECM, amongst others.


If, however, it gets the weather wrong for next weekend, we can draw a different conclusion.


An adjustment 300 miles north of this GEM chart would be fun for many (way into FI, I accept)...



Originally Posted by: Whether Idle 


That looks superficially very good. If you run the sequence you can see the warm air advection is angled SW to NE, under pressure from the jetstream riding over the top.  For a sustainable block we need WAA due north or west of north (which is what happened in December 2010, and not once but twice within a few days).


But as you say that would be an entertaining last hurrah of this cold spell.


It also goes to show just how many outcomes are still possible; pretty much everything from south-westerlies through north-easterlies, easterlies and high pressure.


Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Retron
10 January 2016 16:53:01


Indeed, thanks for the up to date verification stats.


Originally Posted by: Whether Idle 


It's actually quite amusing this - to be honest, the difference (which is 0.001 on that chart) means sweet fanny adams, diddly squat, zilch.


You see, those stats are tracking the performance at the 500hPa level for the whole hemisphere. We, of course, are really only concerned with a very small chunk of that and alas, no stats are available for just our region (as far as I'm aware). Furthermore, what happens at the surface is of more concern on a day-to-day basis and again no stats are available for that either (again, as far as I'm aware).


Even if the 0.001 related purely to Britain, it still wouldn't actually matter as it's so small as to be statistically irrelevant.


In short: don't sweat it, is my view. Even the gap between ECM and MetO/GFS, an order of magnitude greater, still isn't really going to be noticeable to the casual observer.


Back to more serious matters, the differences between the MetO and GFS as early as 96 are stark. I'm especially interested in the way the upper heights "leak" SE'wards over Greenland on the MetO run (a consistent theme), whereas with GFS they instead ooze away into Canada (again, a consistent theme). ECM also shows the upper heights in Greenland being tapped into by the Atlantic ridge.


For what it's worth, given that sensititivity to starting data was being mentioned on Friday, you would (IMO) expect the ECM to do the best out of it - simply because it has more observations and more data going into its runs. (That's the main reason it does so well, it's also the reason it takes so long to come out!)


 


 


Leysdown, north Kent
Gandalf The White
10 January 2016 16:54:44


 


GFS been doing well and beating UKMO...


http://www.emc.ncep.noaa.gov/gmb/STATS/html/new_acz5.html


Originally Posted by: Nordic Snowman 


LOL.


by one-tenth of one percent.....


Still lagging behind ECM though.


 


Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Whether Idle
10 January 2016 16:58:19


 


It's actually quite amusing this - to be honest, the difference (which is 0.001 on that chart) means sweet fanny adams, diddly squat, zilch.


You see, those stats are tracking the performance at the 500hPa level for the whole hemisphere. We, of course, are really only concerned with a very small chunk of that and alas, no stats are available (as far as I'm aware).


Even if the 0.01 related purely to Britain, it still wouldn't actually matter as it's so small as to be statistically irrelevant.


In short: don't sweat it, is my view. Even the gap between ECM and MetO/GFS, an order of magnitude greater, still isn't really going to be noticeable to the casual observer.


 


 


Originally Posted by: Retron 


What you say I agree with Darren, but at times like this - where fans of cold weather will be hoping then GFS is wrong versus UKMO - its worth noting these details to help guard against confidence in a particular outcome.


Dover, 5m asl. Half a mile from the south coast.
Brian Gaze
10 January 2016 17:00:30


 


It's actually quite amusing this - to be honest, the difference (which is 0.001 on that chart) means sweet fanny adams, diddly squat, zilch.


You see, those stats are tracking the performance at the 500hPa level for the whole hemisphere. We, of course, are really only concerned with a very small chunk of that and alas, no stats are available for just our region (as far as I'm aware). Furthermore, what happens at the surface is of more concern on a day-to-day basis and again no stats are available for that either (again, as far as I'm aware).


Even if the 0.001 related purely to Britain, it still wouldn't actually matter as it's so small as to be statistically irrelevant.


In short: don't sweat it, is my view. Even the gap between ECM and MetO/GFS, an order of magnitude greater, still isn't really going to be noticeable to the casual observer.


Originally Posted by: Retron 


 That cuts both ways though and applies equally when the UKM is fractionally ahead of GFS. 


Brian Gaze
Berkhamsted
TWO Buzz - get the latest news and views 
"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
Retron
10 January 2016 17:02:26


What you say I agree with Darren, but at times like this - where fans of cold weather will be hoping then GFS is wrong versus UKMO - its worth noting these details to help guard against confidence in a particular outcome.


Originally Posted by: Whether Idle 


At times like this you may as well shake the tea-leaves in the bottom of the teapot - it makes about as much difference!


A 0.1% difference across the whole bloomin' hemisphere is utterly insignificant.


It's a shame there are no stats for just our little part of the world, or even Europe as a whole; especially for SLP, I've a feeling the numbers would be quite different.


 


 


Leysdown, north Kent
Maunder Minimum
10 January 2016 17:06:46


http://www.bbc.co.uk/weather/features/35276469


 


Chris Fawkes and the latest Beeb 'Weather for the week ahead'. In recent times this has taken a tentative look out to 7 days but it's a reflection of the model uncertainty that Chris stops on Friday.


Originally Posted by: Bertwhistle 


Hugely disappointing forecast for English snow lovers, but decent enough for the high ground in the north. The trough just does not dig far enough south to deliver for snow starved southerners.


New world order coming.
Retron
10 January 2016 17:07:42

Incidentally, the ECMWF do provide stats for just Europe. Here's the error chart for 2M temperatures over the course of the last decade or so.


More stats here:


http://www.ecmwf.int/en/forecasts/charts/medium/verification-high-resolution-forecast-surface-parameters?time=2015122300&parameter=2m%20temperature



Leysdown, north Kent
Gandalf The White
10 January 2016 17:08:30


 


At times like this you may as well shake the tea-leaves in the bottom of the teapot - it makes about as much difference!


A 0.1% difference across the whole bloomin' hemisphere is utterly insignificant.


It's a shame there are no stats for just our little part of the world, or even Europe as a whole; especially for SLP, I've a feeling the numbers would be quite different.


 


 


Originally Posted by: Retron 


I suspect that even several points difference wouldn't be noticeable.  I think these stats are more helpful over a period of many years as an indicator of the general lengthening of the period for a given level of accuracy.


 


Location: South Cambridgeshire
130 metres ASL
52.0N 0.1E


Whether Idle
10 January 2016 17:09:31


 


At times like this you may as well shake the tea-leaves in the bottom of the teapot - it makes about as much difference!


A 0.1% difference across the whole bloomin' hemisphere is utterly insignificant.


It's a shame there are no stats for just our little part of the world, or even Europe as a whole; especially for SLP, I've a feeling the numbers would be quite different.


 


 


Originally Posted by: Retron 


Again, I agree, and that opinion is based model watching in the tiny global vicinity of the UK.


And moving on, its fair to say for the UK at the moment FI is around 96 hours...


Dover, 5m asl. Half a mile from the south coast.
Retron
10 January 2016 17:11:30

One final post on errors by me - here's the stats for November, courtesy of the ECM. Oddly, the 12z ECM run was more accurate in FI than the 0z run!



Leysdown, north Kent
Brian Gaze
10 January 2016 17:14:14


 


We're still in the same position that we have been for quite a few runs now.


Essentially GFS still wants to spit some energy off the main LP that moves up to Arctic Canada from T+48.  An innocous shallow trough forms south of the tip of Greenland which cuts of any WAA from the next LP system and opens the door for energy to surge east.


UKMO just shows the trough dissipating which both keeps the residual upper ridge in place and allows for the next burst of WAA.


GEM shows the same trough, albeit slightly later, but again like UKMO doesn't develop it.


I guess the good news is that we're only 24-48 hours from having this resolved.


 


Originally Posted by: Gandalf The White 


The majority of the GEFS12z follow the op run today but a significant number go gown the UKM route.


Brian Gaze
Berkhamsted
TWO Buzz - get the latest news and views 
"I'm not socialist, I know that. I don't believe in sharing my money." - Gary Numan
Whether Idle
10 January 2016 17:14:18


One final post on errors by me - here's the stats for November, courtesy of the ECM. Oddly, the 12z ECM run was more accurate in FI than the 0z run!



Originally Posted by: Retron 


All eyes on the 12z JMA then


Dover, 5m asl. Half a mile from the south coast.
Retron
10 January 2016 17:16:07

GEFS 120 stamps - click for large view.



A few members there which are along the lines of MetO, but not that many!


Leysdown, north Kent
Retron
10 January 2016 17:17:08


All eyes on the 12z JMA then


Originally Posted by: Whether Idle 


Lower is better on that chart. 


(Note also the interesting swap between GFS and ECM by day 10 - not seen that pop up anywhere else!)


Leysdown, north Kent
Nordic Snowman
10 January 2016 17:23:29


 


LOL.


by one-tenth of one percent.....


Still lagging behind ECM though.


 


Originally Posted by: Gandalf The White 


 Given the output tonight, I actually want the UKMO to be right too.... although that's wishful thinking as the UKMO T144 is so awful


GEM is also chopping and flipping all over the place too. I bet ECM takes a different route tonight too...


Bjorli, Norway

Website 
Whether Idle
10 January 2016 17:26:28


GEFS 120 stamps - click for large view.



A few members there which are along the lines of MetO, but not that many!


Originally Posted by: Retron 


Take ptb 5 here, way into FI at day 7, this is the ideal cold scenario IMBY,   with a Polar Continental, this follows from an UKMOish outcome at day 5, so really once the upstream issue is resolved, it needs to be UKMO/GEMish and then it could result in a real cold blast.  If GFS has it right, which it may well have, then its back to mild dross, daffodils, crocuses and growing grass, oh, and probably more floods up north.


Ptb 5 850s GFS 12z:



Dover, 5m asl. Half a mile from the south coast.
Whether Idle
10 January 2016 17:31:15


 


Lower is better on that chart. 


(Note also the interesting swap between GFS and ECM by day 10 - not seen that pop up anywhere else!)


Originally Posted by: Retron 


Of course I meant all eyes on the ECM 12z for day 5


Dover, 5m asl. Half a mile from the south coast.
Gooner
10 January 2016 17:39:58


 


Hugely disappointing forecast for English snow lovers, but decent enough for the high ground in the north. The trough just does not dig far enough south to deliver for snow starved southerners.


Originally Posted by: Maunder Minimum 


So Thursday is warmer than today IMBY.....................not a cat in hells chance .


As for specifics dont take thse too seriously , Ive seen Sunday forecasts for the week before and when the day arrives later in the week its very different


Remember anything after T120 is really Just For Fun



Marcus
Banbury
North Oxfordshire
378 feet A S L


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