SMU

GFS 06 out to 66- already more incremental swings to the UKMO in terms of amplifcation- I will post the 126 00z V the 120 06z for comparison... s

Yes mate it snowed all day sat although bexleyheath ( IMBY) the front fizzled a bit - where as to the SW on the downs they got 3-4 inches ( nearer 1.5/2 here ) This is a similar scenario here although perhaps not as condusive to snow - more prolonging the deep cold as its difficult to really see where the UKMO goes past 144 - the atlantic shortwave is to accute to get into the UK but does stop the sinker - the high could respread Nw & NE so 168 is deffo still very cold but thereafter - unsure.... As no visibilty of shortwave pattern.... S

Cheers HP infact looking at my post without opening any image & just looking down on the actual 19th V the UKMO chart in terms of the global anomalies both high & low heights - the UKMO was spectacularly good - I would go as far as to say thats one of the best modelled V verified charts ive ever seen - If ian reads this its certainly a thumbs up for the UKMET model.... S

So here it is - shock proof the UKMO can pawn all the models at the most critical of times - & importantly when we needed it the most An UKMO 144 chart that varifies very close & the GFS / ECM are miles away- note the scenario - Blocking to the NE & undercutting energy. These are the 2 actual verification charts for 19th & 21st jan 2013 - it demonstrates the EXACT position we are in today- with the models at day 6 UKMO spot on at day 6, GFS miles away & ECM thinking of a different scenario - Then continue to day 8 ( GFS & ECM ) to show how wrong they were so - verified charts sat 19 & mon 21st 13 2 classic undercutting charts - with sub zero maxima across england & a band of snow moving ESE - a great day that one. So rewind to the 12z 's of the 13th 6 days before - at just T144 you would expext the models to be indicating this undercut & possible snow event - UKMO DAY 6 12z as you can see thats a fair crack of the whip - all the energy going in the the right direction (SE) & snow on its way now take the ECM 144 & 192 as you can see a little energy going under but at day 6 nothing - but it does get there at day 8 - with a more pronounced under cut- Now onto out favourite rollercoaster model the GFS Day 6 sees all but a tiny bit of energy moving SE at day 6 with no easterly - which then translates to a mild SW flow developing at day 8 .... So going on from what ive said since 1st Jan is that once a blocking high to the North or NE is in place the UKMO seems to deliver better resolution to the locale of the high & subsequent jet disruption - even the ECM looks weak in its modelling- This was backed up by Ian F yesterday in shorter fashion by saying the same thing. so while we cant 'expect' it - at least we can safely say the UKMO could be the lead here not the GFS.... S thanks Pm

^^^^^ its the GFS falling towards the UKMO more amplified solution though not the other way round look at the above charts then take the 00z 144 GFS from yesterday which is the same time as today's 120s above you can see before the energy is progged over the block now today it's going under not mega swings in the height distribution but subtle swings in the shortwave pattern with big impacts on the UK s

Morning all updating my post from last night ( & reinforcing what I said around 10 days ago when I said the models would flip - when they partially did ) is one of the biggest model failures ( or bias ) - especially the GFS is to move energy NE through a block - then as we approach real time so the final distribution often sees that replaced more & more By SE movement & the potential for prolonging the cold The overnight model suite has seen fairly moderate model changes & fine tuning - but notable very positive moves ( a slight whiff of 96 in the air ) towards the colder solution ... so, UKMO has back peddled the least but ever so slightly reduced the northern extent of the blocking - but crucially gets enough of a trivial persuit size wedge in there that at 144 theres the majority of the atlantic energy is moving SE - delivering a dead cert snow event for the SW - ( if the low ever gets that far ) I would also say the East & SE is covered by the -10c isotherm at day 6 ( slight resemblance to Jan 85 in its most positive light ) & would see a continuation of the cold spell out well past day 6 UKMO ( the new anti global warming model ) - A+ The GFS & ECM blend are less amplified & send a more even distribution of energy NE & SE allowing less undercutting - crucially though both models get enough SE to hold a cold SE flow into the front to see a snowy breakdown over the UK but eventually topple it all away - B- which is a big swing to cold after yesterdays C- In my experience where models are swinging to more energy going SE at day 6 against the block the trend for day 5 ( backing into day 4 ) shows the biggest continued trend of swinging to more energy SE so todays the day where if its going to happen the UKMO becomes the hero.... S

Evening All- I echo the sentiments of many here by enjoying the models struggle with this very diverse change in weather pattern & relating to that its unlikely that any model will escape without some war wounds- I do love the UKMOs modeling of late - hellbent on delivering the cold solutions out of unlikely circumstances - however the UKMO ( & navgem ) are at the extreme end of the ensemble suite - IE maintaining very cold air - & crucially keeping the element of instability available with it- this born out of the slowest jet profile allowing the biggest wave amplitude ( although the indian model shown earlier was even more extreme to say the least ) The ECM is the other end of the spectrum with the jet being pretty fast & overpowering leading to warm & probably wet weather for all the wrong areas... The middle ground is of course the slow return of milder air at day 9/10 - not day 8 like the ECM so if your looking for cold longer then the swing required isnt that much out if the models- just a bit more amplification to start with- however to get to the UKMO & NAVGEM solutions ( cold & possible snow ) is a considerable leap & maybe a bit of a big jump to make... can the UKMO / NAVGEM blend really land over the mighty ECM .... Yes ... Its happened before ( site Jan 13 undercut ) it may happen again... S

On the subject of temps GFS now showing a -15c - somewhere T'up north....

Lol GFS nearly pulls it out the bag

Evening All - As the days modelling comes to a close ( excluding the volatile pub run ) I cant help feel a tinge of disapointment As we head into the week- now the models have settled down we do see a window open for most to see some snow falling this week & again this could translate to some coverage- especially the Further North & west you go, then some very cold nights post that- However against the backdrop of what might have been - It all feels a bit second hand- Its pretty seeing the cold -7s over the Uk but its only really in situ for 2 / 3 days before the instability is capped post that because of the timeframes that high could so easily morph into a better more Northerly locale - & then its a different story - like the ECM control maybe ? however if it lands like the average mean looks tonight then I do agree - day 10 is the 20th so realistically were not far off the end of jan & 2 thirds of winter down without to much excitement... which would leave february .... as I mentioned a few times though despite forecats & otherwise you get the feeling this year isnt going to deliver for the UK- it feels an eastern europe / Greece type winter - i hope that it gets proved wrong.... S

IMBY FOR THE NW KENT MOB

Message me tomorrow good height build as expected TBH after the 168 it was only going 1 way - nice easterly at 216 - then at the very least a very cold high at 240 ! s

Big inflection point in the jet over the atlantic at 168- energy going SSE - azores high having another go like a persistent yorkshire terrier....

Evening All - Well well again, a better day ( so far ) as the models take a turn for the better - more especially the UKMO that seems to have embarked on its own personal agenda of showing great synoptics despite other models being a little more progressive - Indeed the UKMOs slow solution shows perhaps, slightly more blocking available than that of the perceived amount after the collapse of the GH ridging yesterday- So as we have moved through today the threat of the iberian low seems to be receeding - but still poses a threat to the south- This is probably down to ironically the shortwave low that develops over SW greenland at the time where we didnt want it to develop - what we are seeing is the delicate rebalancing of the energy distribution of the jet - with more SE flow & less poleward thrust - The net today is that -6c line becomes ever more tantalising to the south coast- This embedded cold remains in situ as we wait for the models to resolve the next bout of energy moving in what direction??... ENE - booooo ESE - yaaaaa The models with the coldest outcomes will be ESE- We await the much awaited ECM 12z with an air of anticipation & perhaps with renewed optimism.... S

Well well well - it wouldnt be the UK without a bit of model 'Eastenders' So the unthinkable has happened - the glorious super -AO & -NAO has gone the way of the pair ( latin -Titicus verticus ) to be replaced by something more ordinary ... credit to the GFS for its consistency WRT the way its resolved the conflict of energy over western greenland - with the euros off the mark - it doesnt happen often but when it does its always when forecasting uk cold - typical !! What we are left with is a messy evolution with no clean entry of cold - just bitty features supporting the colds journey into the UK & towards the elusive south coast - Without the big chunky Greenland high the drive south will be tempered - a bit like the enthusiam on here tonight - but its not all lost - the fat lady is just dishing up her spotty dick - & theres time before she clears here throat - We do still have a push south of the cold air of varying degrees & we do still see a push north of the mild air - Wherever they meet promises to be a snow event - However as ever the detail is very elusive - looking at the combined outlook just for the cold air only - in terms of its defined progression south - the midlands - up to the penines would be a good place for an early call to the bookies ..... Thats all that can be gleaned from the models at the moment- anyone forecasting any definites shouldnt be taken to seriously... cheers S PS I would still take EcM day 10 over the last weeks of projections from an IMBY POV

Last one from me before the 12s whilst we seemingly have 3 areas of activity to worry about in the 120 arena we must remember they are all linked to each other within a system - the movement of one impacts the others Therefor the jet profile I highlighted earlier & whether it lifts out of western greenland quicky or produces a cut off low then snowballs on the angle of the jet in the atlantic at 144- If we get what the UKMO says with no residual energy & it all lifting out the high pressure can rapidly fill in situ - the net forcing then is energy from the pole moving south towards the UK bringing the very cold air, but also the higher pressure in the atlantic will steer any icelandic shortwave SSE & the subtropical low ENE - missing the UK to the south if there is more residual energy driven SSE into SW greenland at 120 producing a closed low then the atlantic ridging is weak with the net energy unable to drive the icelandic shortwave south- also giving little or no resistence North to the subtropical low - so all eyes on the 12s should be in that area - treat it like a sliding scale - more energy out & up NE like UKMO then cold uk more energy SSE & an area of low pressure = short cold for UK mild SW winds to ensue as subtropical low heads towards scotland- Middle ground is cold for slightly longer but same result as the above point - mild from the SW soon after - around day 10 - taking us mild from 17th Jan ish... we must have NO energy then which is why the UKMO worries me slightly as its grid may be missing that energy in situ that the GfS has spotted .... s

Unlikely TBH starting conditions probably relate to subtropical low or the current atlantic low the system Im talking about ( or process ) of energy going SSE over greenland is at 120 S

No SE the more energy that drops SSE the more of an issue it is... s

Guys - your focussing to much in the wrong area - The subtropical low isnt the problem... ( we seem to have weathered that mostly ) The problem is how much energy is digging SE towards SW greenland at around 120 The simple explanation is the less that digs ( & lifts out ) the better the high pressure in the atlantic is There is a 50/50 balance between all the models & indeed the ensembles - so noone can tell... middle ground is the NAVGEM 00z as you see the enrgy lifts out NE & high pressure builds - also UkMo lifts it out as well thats the area to watch tonight - if we get a close off low digging SE to iceland its game over for the most part if it all lifts out like the Euro etc then were fine... CIAO

Dont hate the azores low - love it ( dont hate it ) - as long as it doesnt get to far north ... its a snow bringer .... These 2 charts never get a mention in the archives but the second one had the most fierce easterly ever.. its what happens when you spike the subtropical jet north out of spain against high pressure over greenland - s

Can we have the maxima 216/240

It wont matter - low heights / still air / -6c air = deep frost & ice days !!! once were at ECM 240 the uppers are irrelevent .... wheres the 240 snow chart & t2Ms!! S

Well boom town charts from the JMA & ECM - identical to Nov 2010 3 key ingredients * greenland high * shortwave Energy crossing norway into scotland amoung deep cold * subtropical energy sliding ENE across spain & france forcing all the cold to the UK ECM JMA 2010 S

One to watch * At 168 the ECM has energy in the subtropical jet around portugal - This will push east / North east - at worst in drives the european cold west at best it slides up the uk delivering Snow - S

Lol I wrote that 10 years ago !